WO2022259972A1

WO2022259972A1 - Injection apparatus and molding machine

Info

Publication number: WO2022259972A1
Application number: PCT/JP2022/022600
Authority: WO
Inventors: 眞辻; 俊昭豊島; 敏彰中野; 俊治藤岡; 三郎野田
Original assignee: 芝浦機械株式会社
Priority date: 2021-06-08
Filing date: 2022-06-03
Publication date: 2022-12-15
Also published as: JP2022187608A

Abstract

An injection apparatus 9 comprises an injection cylinder 27, a liquid-pressure device 43, a second electric motor 31B, and a control device 5. The injection cylinder 27 is coupled to a plunger 21 that extrudes a molding material M into a mold 101. The injection cylinder 27 also has a booster piston 41 that can be moved forward and backward. The liquid pressure device 43 supplies a hydraulic liquid to the injection cylinder 27. The second electric motor 31B is coupled to the booster piston 41. The control device 5 performs control on the liquid-pressure device 43 and the second electric motor 31B so as to simultaneously impart, to the booster piston 41, a first force, which is generated by the hydraulic liquid and which acts forward, and a second force, which is generated by the second electric motor 31B and which acts backward, and thereby cause the booster piston 41 to move forward.

Description

Injection device and molding machine

The present disclosure relates to an injection device and a molding machine including the injection device. The molding machine is, for example, a die casting machine for molding metal or an injection molding machine for molding resin.

As an injection device that uses a plunger to push out a molding material into a mold, there is known a so-called hybrid type in which the plunger is driven by a hydraulic (e.g., hydraulic) drive unit and an electric drive unit (e.g., Patent Documents 1 to 3 below). Such an injection device has an injection cylinder connected to a plunger and an electric motor connected to a member (for example, a piston) of the injection cylinder. The driving force generated by supplying the hydraulic fluid to the injection cylinder and the driving force by the electric motor simultaneously act on the plunger in the same direction (for example, the direction in which the plunger faces the mold) during an appropriate period during injection. or either one is selectively used.

JP-A-2008-155280 JP-A-2006-315071 JP 2014-18840 A

Various conventional hybrid injection devices each have their own advantages and disadvantages. On the other hand, user demands are diverse. Therefore, it is not always possible to provide the user with an injection apparatus that can satisfy the user's request. In view of the above, it is desirable that the provision of a hybrid type injection apparatus of a new mode will enrich the technology and, in turn, increase the probability that user's demands will be satisfied.

An example of user requests (problems) is given below. However, the technique according to the present disclosure does not necessarily require that the problems exemplified below can be solved.

In general, using an electric drive can save energy consumption compared to using a hydraulic drive. As a result, carbon dioxide reduction is also expected. Further, the electric drive section can be controlled with higher precision than the hydraulic drive section. Under these circumstances, there is a high need for electrification of injection apparatuses as well.

After the molding material is filled in the mold, the injection device may perform pressure increase to increase the pressure applied to the molding material by the plunger and hold pressure to maintain the increased pressure due to the pressure increase. Increased pressure and hold pressure reduce porosity (voids on or inside the product) that occur, for example, with shrinkage of the molding material as it cools in the mold.

Increasing and holding pressure require a relatively large driving force and its maintenance. Therefore, when the pressure is increased and the pressure is maintained by the electric motor, the size of the electric motor is increased and the power consumption is increased. The result is a mismatch with the user's desire to reduce energy consumption, for example by using electric motors. As a result, it is not possible to meet the user's demand for setting a long pressure holding time.

An injection device according to one aspect of the present disclosure includes an injection cylinder, a hydraulic device, an electric motor, and a control device. The injection cylinder is connected to a plunger that pushes molding material into the mold. The injection cylinder also has a piston movable in a first direction and a second opposite direction. The hydraulic device supplies hydraulic fluid to the injection cylinder. The electric motor is connected to the piston. The control device simultaneously applies a first force in the first direction by hydraulic fluid and a second force in the second direction by the electric motor that is smaller than the first force to the piston. , thereby controlling the hydraulic system and the electric motor to move the piston in the first direction.

A molding machine according to one aspect of the present disclosure includes the above injection device and a mold clamping device that holds the mold.

According to the above configuration, a new mode of injection device and molding machine is provided in which the piston is moved in the direction of the force of the hydraulic fluid while the force of the electric motor is applied in the opposite direction to the force of the hydraulic fluid.

Schematic diagrams for explaining an overview of the operation of the injection device according to the embodiment. FIG. 2 is a schematic diagram for explaining the continuation of FIG. 1; FIG. 3 is a schematic diagram for explaining the continuation of FIG. 2; FIG. 4 is a schematic diagram for explaining the continuation of FIG. 3 ; FIG. 5 is a schematic diagram for explaining the continuation of FIG. 4 ; FIG. 2 is a side view showing the configuration of the main parts of the die casting machine according to the embodiment; FIG. 7 is a top view showing the configuration of the main parts of the die casting machine of FIG. 6; FIG. 7 is a cross-sectional view schematically showing the configuration of the main part of the injection device of the die casting machine of FIG. 6; FIG. 7 is a circuit diagram showing an example of a hydraulic device of the die casting machine of FIG. 6; FIG. 7 is a diagram for explaining the operation of the injection device of the die casting machine of FIG. 6; FIG. 7 is a view for explaining a modification of the operation of the injection device of the die casting machine of FIG. 6; FIGS. 12(a), 12(b), 12(c) and 12(d) are diagrams for explaining an injection device according to a modification; FIG.

<Outline of operation of die casting machine>
1 to 5 are schematic diagrams for explaining an overview of an example of the operation related to injection of the die casting machine 1 according to the embodiment. The operation related to injection progresses in order from FIG. 1 to FIG. In the following description, for convenience, the left side of these figures may be referred to as the front, and the right side of these figures may be referred to as the rear.

The die casting machine 1, for example, injects (fills) the molten molding material M into the mold 101 (cavity 107) to manufacture a product (molded product, die cast product) made of the solidified molding material M. configured as a device.

The procedure for injecting the molding material M into the cavity 107 is as follows. Molding material M is fed into sleeve 19 leading to cavity 107, as shown in FIG. Then, as shown in FIGS. 1 to 3, the molding material M inside the sleeve 19 is pushed out into the cavity 107 by the plunger 21. As shown in FIGS. That is, injection in the narrow sense is performed. Next, the molding material M is pressed by the plunger 21 to increase the pressure (FIG. 4). That is, the pressure is increased. After that, the molding material M is maintained under increased pressure (FIG. 5). That is, holding pressure is performed. While the holding pressure is being performed, the molding material M is solidified by being deprived of heat by the mold 101 .

In order to drive the plunger 21 as described above, the die casting machine 1 performs the following operations.

First, as indicated by arrow a1 in FIG. 2, hydraulic fluid (for example, oil) is supplied from the accumulator 47 to the back of the injection piston 37 (head side chamber 35h). This causes the injection piston 37 to move forward. As a result, the plunger 21 connected to the injection piston 37 advances. As a result, injection (narrowly defined) is performed.

Next, as indicated by an arrow a2 in FIG. 3, the hydraulic fluid in the accumulator 47 is also supplied behind the pressure boosting piston 41 (rear side chamber 35a) before injection (narrowly defined) is completed. That is, the booster piston 41 receives forward force from the hydraulic fluid. On the other hand, the booster piston 41 receives a rearward force from the electric motor 31 as indicated by an arrow a3. The rearward force due to the electric motor 31 is greater than the forward force due to the hydraulic fluid. Therefore, the booster piston 41 does not advance (stops).

Next, as represented in FIG. 4 by drawing arrow a4 smaller than arrow a3 in FIG. less than the forward force exerted on 41 . As a result, the boosting piston 41 starts moving forward. That is, the pressure-increasing piston 41 does not start moving forward by starting supply of hydraulic fluid to the back of the pressure-increasing piston 41 (opening operation of a valve (not shown) from another point of view). Start moving forward by being made small.

At the time when the pressure-increasing piston 41 starts moving forward, or at a time before or after that, discharge of hydraulic fluid from the head-side chamber 35h is prohibited. The pressure-increasing piston 41 transmits the force received from the hydraulic fluid in the rear (rear side chamber 35a) to the hydraulic fluid in the head side chamber 35h. Here, the pressure-increasing piston 41 has an area (pressure-receiving area) that receives pressure from the hydraulic fluid in the rear chamber 35a larger than an area that receives pressure from the hydraulic fluid in the head-side chamber 35h. Therefore, the pressure increasing piston 41 can increase the pressure applied from the accumulator 47 to the rear side chamber 35a and apply it to the head side chamber 35h. As a result, the pressure applied to the molding material M by the plunger 21 is increased, and the pressure is increased.

During pressure increase, the driving force of the electric motor 31 is controlled to gradually decrease. As a result, the pressure applied to the head-side chamber 35h by the pressure-increasing piston 41 is gradually increased. That is, the control of the pressure applied from the plunger 21 to the molding material M by the action of the pressure-increasing piston 41 is not performed by controlling the supply and/or discharge of the hydraulic fluid (for example, flow rate control), but by controlling the electric motor 31. It is realized by controlling the driving force.

After that, the electric motor 31 is brought into a state in which it does not generate driving force (for example, a torque-free state of the rotary electric motor), as indicated by the absence of the arrow a4 (FIG. 4) in FIG. . In other words, substantially only the hydraulic fluid force is applied to the intensifier piston 41 . Holding pressure is performed by maintaining this state.

As described above, in this embodiment, the force for moving the pressure-increasing piston 41 forward is different from the force applied to the pressure-increasing piston 41 forward by the hydraulic fluid, and the force applied to the pressure-increasing piston 41 rearward by the electric motor 31. obtained by the difference. Therefore, for example, while the force for driving the pressure intensifying piston 41 forward can be obtained by the hydraulic drive unit, the force can be controlled by the electric drive unit. The control of an electric drive is generally more responsive and has smaller deviations than the control of a hydraulic drive (eg control of hydraulic fluid flow by a valve). Therefore, for example, the start timing of pressure increase can be controlled with high accuracy, and the pressure of the molding material M during pressure increase can be controlled with high accuracy. Also, the electric motor 31 does not have to be driven during pressure holding. For example, it is sufficient to apply the pressure accumulated in the accumulator 47 to the rear side chamber 35a. Thereby, for example, power consumption can be reduced.

<Specific example of die casting machine>
The configuration and operation of the die casting machine 1 described above are applicable to various die casting machines. In other words, the die casting machine 1 according to the embodiment may be embodied as appropriate. Below, an example of the die-casting machine 1 embodied is shown.

(Overall configuration of die casting machine)
FIG. 6 is a side view (partially including a cross-sectional view) showing the configuration of the main parts of the die casting machine 1. As shown in FIG. FIG. 7 is a top view showing the configuration of the essential parts of the die casting machine 1. As shown in FIG. In each figure, illustration of various members is omitted for the sake of convenience. Thus, for example, the illustration of components that are illustrated in FIG. 6 and should also be visible in FIG. 7 may be omitted from FIG. And vice versa.

The already-described molding material M (not shown here) is, for example, a metal such as aluminum. Metal in a molten state is sometimes called molten metal. A molding material in a solid-liquid coexistence state (semi-solidified or semi-molten state) may be injected into the cavity 107 instead of the molten molding material.

The mold 101 has, for example, a fixed mold 103 and a movable mold 105 facing the fixed mold 103 . A cavity 107 into which the molding material is injected is constructed between the fixed mold 103 and the movable mold 105 . The fixed mold 103 is a mold that does not move. The movable mold 105 is a mold that moves in a direction opposite to the fixed mold 103 (mold opening/closing direction). The mold opening/closing direction is, for example, the horizontal direction.

The die casting machine 1 has a machine body 3 that performs mechanical operations and a control device 5 that controls the machine body 3 . The machine body 3 includes, for example, a mold clamping device 7 for opening/closing and clamping the mold 101, an injection device 9 for injecting molten metal into a cavity 107, and a fixed mold 103 for producing a product formed by solidifying the molten metal. Alternatively, it has an extrusion device (not shown) that extrudes from the moving mold 105 . Note that the control device 5 may be regarded as a component of the injection device 9 .

In the die casting machine 1, except for the configuration and operation of the injection device 9, the configuration and operation of other components (for example, the mold clamping device 7 and the extrusion device) may be various configurations and operations. may be constructed and operated. Therefore, descriptions of the configurations and operations of the other components will be omitted as appropriate. Note that the operation of the injection device 9 is control of the injection device 9 by the control device 5 from another point of view. The configuration and operation of the mold clamping device 7 and the configuration of the control device 5 will be briefly described below. After that, the configuration and operation of the injection device 9 will be described.

The mold clamping device 7 includes, for example, a base 11, a fixed die plate 13 fixed on the base 11, a movable die plate 15 movable on the base 11 in the mold opening/closing direction, and a die plate inserted through these die plates. and a plurality of (for example, four) tie bars 17 . The fixed die plate 13 and the movable die plate 15 face each other in the mold opening/closing direction. The stationary die plate 13 holds the stationary die 103 on the surface facing the movable die plate 15 . The movable die plate 15 holds the movable die 105 on the surface facing the fixed die plate 13 . The mold 101 is opened and closed by moving the movable die plate 15 in the mold opening/closing direction. In addition, when the tie bars 17 are extended while the mold is closed, a mold clamping force corresponding to the amount of extension is applied to the mold 101 .

For example, the control device 5 may be configured including a computer, although not shown. The computer may include, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and an external storage device (not shown). Various functional units that perform various calculations (including control) are constructed by the CPU executing programs stored in the ROM and/or the external storage device. Also, the control device 5 may include a logic circuit that executes a certain operation, may include a power supply circuit, or may be conceptualized including a driver. The control device 5 may be integrated in one place in terms of hardware, or may be distributed in a plurality of places.

(Injection device)
The injection device 9 is positioned behind the fixed die plate 13 (opposite to the movable die plate 15). The injection device 9 has the previously described sleeve 19 and plunger 21 , and a drive section 23 for driving the plunger 21 . In addition, since the sleeve 19 and the plunger 21 can be regarded as consumables, only the driving part 23 may be regarded as the injection device.

The configurations of the sleeve 19 and the plunger 21 may be various configurations, such as known configurations. In the illustrated example:

The sleeve 19 is provided so as to be inserted through the fixed die plate 13 . The sleeve 19 may not be inserted through the fixed mold 103 (example in FIG. 6), or may be inserted through (see FIG. 1). The sleeve 19 is a generally cylindrical member and is arranged to extend in the horizontal direction (front-rear direction). A supply port 19a through which molten metal is supplied is opened in the upper surface of the sleeve 19 .

The plunger 21 has a plunger tip 21a that slides on the sleeve 19 and a plunger rod 21b fixed to the plunger tip 21a. The plunger rod 21 b extends in the front-rear direction, and its rear end is connected to the driving portion 23 by a coupling 25 .

FIGS. 6 and 7 show the state before the start of injection (see also FIG. 1). At this time, the plunger tip 21a is positioned (at least partially) inside the sleeve 19 behind the supply port 19a. In this state, molten metal is poured into the supply port 19a by a hot water supply device or the like (not shown). Next, the plunger tip 21 a slides (advances) toward the cavity 107 by the driving force of the driving portion 23 . The molten metal is thereby injected into the cavity 107 .

(Drive part)
FIG. 8 is a cross-sectional view schematically showing the configuration of the main parts of the injection device 9. As shown in FIG. This figure is a view of the injection device 9 viewed from above. However, for the sake of convenience, components that are not visible from the top surface (second electric motor 31B, etc., which will be described later) are also shown.

The injection device 9 (drive unit 23) has an injection cylinder 27 that is connected to the rear end of the plunger 21 by a coupling 25. Hydraulic fluid (oil, for example) is supplied to the injection cylinder 27 from a hydraulic device 43 (see FIG. 9, which will be described later). As a result, the injection device 9 can apply a hydraulic driving force to the plunger 21 .

In addition, the injection device 9 has two first driving devices 29A each including a first electric motor 31A. The first driving device 29A has a detachable portion 33 that can connect and disconnect the injection cylinder 27 to a piston rod 39, which will be described later. Thereby, the injection device 9 can apply an electric driving force to the plunger 21 .

Further, the injection device 9 has a second driving device 29B including a second electric motor 31B. The second drive device 29B is connected to the booster piston 41 of the injection cylinder 27 . The second electric motor 31B is an electric motor corresponding to the electric motor 31 described with reference to FIGS. Here, the electric motor 31 is referred to as a second electric motor 31B to distinguish it from the first electric motor 31A.

The outline of the operation of the injection device 9 when injecting the molding material M into the mold 101 is as described with reference to FIGS. 1 to 5. As can be understood from the description of FIGS. 1 to 5, the operation from the start of injection to the completion of holding pressure is realized by supplying hydraulic fluid to the injection cylinder 27 and driving the second electric motor 31B. The first electric motor 31A, for example, contributes to retracting the plunger 21 after the pressure holding is completed.

(Injection cylinder)
The injection cylinder 27 is arranged coaxially with the plunger 21 behind the plunger 21, for example. The injection cylinder 27 includes, for example, a cylinder member 35 , an injection piston 37 slidable inside the cylinder member 35 , a piston rod 39 extending forward (toward the plunger 21 side) from the injection piston 37 , and a and a pressurizing piston 41 capable of pressurizing the hydraulic fluid.

The cylinder member 35 is, for example, a generally cylindrical member. The internal cross-sectional shape of the cylinder member 35 is, for example, circular. The outer shape (outer shape) of the cylinder member 35 may be an appropriate shape such as a rectangular parallelepiped shape. The cylinder member 35 is made immovable with respect to the stationary die plate 13 . The cylinder member 35 has a small-diameter cylinder 35x and a large-diameter cylinder 35y connected in series to the rear end of the small-diameter cylinder 35x. The inner diameter of the large-diameter cylinder 35y is larger than the inner diameter of the small-diameter cylinder 35x.

The injection piston 37 is, for example, a substantially cylindrical member. The diameter of the injection piston 37 is roughly the same as the inner diameter of the small-diameter cylinder 35x. A packing (not shown) may be interposed between the injection piston 37 and the small-diameter cylinder 35x. Even when a packing is interposed, the injection piston 37 is expressed as sliding inside the small-diameter cylinder 35x (cylinder member 35). The same applies to other members (for example, the booster piston 41). The space inside the small-diameter cylinder 35x is divided by the injection piston 37 into a rod-side chamber 35r on the side of the piston rod 39 and a head-side chamber 35h on the opposite side.

The piston rod 39 is, for example, a substantially cylindrical member. The diameter of the piston rod 39 is smaller than the diameter of the injection piston 37 . The difference may be set appropriately. The piston rod 39 extends outside the cylinder member 35 and has its front end connected to the rear end of the plunger 21 by a coupling 25 .

The piston rod 39 moves integrally with the plunger 21. Therefore, the injection cylinder 27 is configured to be able to move the piston rod 39 (injection piston 37 ) with a stroke equal to or greater than the stroke assumed for the plunger 21 .

The pressure-increasing piston 41 is composed of, for example, a piston that can slide on the cylinder member 35 . More specifically, the boosting piston 41 has a small-diameter piston 41a that slides on the small-diameter cylinder 35x and a large-diameter piston 41b that slides on the large-diameter cylinder 35y. The large-diameter piston 41b is connected in series with the rear end of the small-diameter piston 41a. Note that, unlike the illustrated example, a connecting portion having a diameter smaller than that of the small-diameter piston 41a may be formed between the small-diameter piston 41a and the large-diameter piston 41b.

A portion of the interior of the cylinder member 35 (35x and 35y) behind the injection piston 37 is partitioned by the pressure-increasing piston 41 into a head-side chamber 35h on the side of the injection piston 37 and a rear-side chamber 35a on the opposite side. there is The interior of the large-diameter cylinder 35y is partitioned by the large-diameter piston 41b into a front chamber 35f on the side of the small-diameter cylinder 35x and a rear chamber 35a on the opposite side. The pressure-increasing piston 41 has a first surface 41c (tip surface of the small-diameter piston 41a) that receives pressure from the hydraulic fluid in the head-side chamber 35h, and a second surface 41d that receives pressure from the hydraulic fluid in the rear-side chamber 35a (rear surface of the small-diameter piston 41a). end face). The area of the second surface 41d is larger than the area of the first surface 41c.

As can be understood from the operations described with reference to FIGS. 1 to 5, the head-side chamber 35h and the rear-side chamber 35a are filled with hydraulic fluid. On the other hand, the rod side chamber 35r and the front side chamber 35f may or may not be filled with hydraulic fluid. For example, the rod side chamber 35r and the front side chamber 35f may be open to the atmosphere. When the hydraulic fluid is not filled, the rod side chamber 35r and the front side chamber 35f may be provided with a small amount of hydraulic fluid (oil) for lubrication.

In the following description, an embodiment in which the rod-side chamber 35r is filled with hydraulic fluid will be taken as an example. The hydraulic fluid in the rod-side chamber 35r contributes, for example, to reducing the probability of the injection piston 37 moving forward at a rapid speed (jumping) at the start of injection, and/or to absorbing surge pressure at the completion of molten metal filling. .

When the front side chamber 35f is filled with hydraulic fluid, this hydraulic fluid may or may not be used for some purpose. As an example of the former, for example, after the pressure holding is completed, hydraulic fluid is supplied from the hydraulic device 43 to the front side chamber 35f to generate at least part of the driving force for retracting the pressure intensifying piston 41. can be done. Further, for example, at an appropriate time, the hydraulic device 43 may be used to prohibit discharge of the hydraulic fluid from the front side chamber 35f, thereby prohibiting unintended forward movement of the pressure boosting piston 41. Moreover, as an example in which the hydraulic fluid in the front side chamber 35f is not used, there is a mode in which the front side chamber 35f and the tank are only connected.

(flame)
Any suitable method may be used to install the cylinder member 35 so as not to move with respect to the fixed die plate 13 . In the example shown in FIGS. 6 and 7, the cylinder member 35 is connected to the fixed die plate 13 by a frame 45. As shown in FIG. The frame 45 also contributes to supporting the first driving device 29A and the like, as will be described later.

The shape of the frame 45 is arbitrary. For example, as shown in FIG. 6, the frame 45 is connected to a first portion 45a positioned between the fixed die plate 13 and the cylinder member 35 to fix them together, and the first portion 45a. and a second portion 45b that supports the cylinder member 35 from below.

The shapes of the first part 45a and the second part 45b are also arbitrary. For example, the first portion 45 a is adjacent to a portion positioned below the plunger 21 ( FIG. 6 , reference numerals omitted), a portion positioned laterally and/or above the plunger 21 ( FIG. 7 ), and the front end of the cylinder member 35 . may have a plate 45c (FIGS. 6 and 7) for

(hydraulic device)
FIG. 9 is a circuit diagram showing an example of the hydraulic device 43 that supplies hydraulic fluid to the injection cylinder 27 to drive the injection cylinder 27. As shown in FIG.

(accumulators, pumps and tanks)
The hydraulic device 43 has an accumulator 47 and a pump 49 as hydraulic pressure sources. The hydraulic device 43 also has a tank 51 that stores hydraulic fluid. Note that the tanks 51 are shown at a plurality of positions for convenience. In practice, the number of tanks 51 may be less than shown, for example only one.

The division of roles between the accumulator 47 and the pump 49 (and the tank 51) may be set appropriately.

In this embodiment, as described with reference to FIGS. 1 to 5, the hydraulic fluid is supplied from the accumulator 47 to the head-side chamber 35h, whereby the injection piston 37 advances and injection is performed. Further, hydraulic fluid is supplied from the accumulator 47 to the rear side chamber 35a, whereby the pressure increasing piston 41 moves forward to increase the pressure. The filling of the accumulator 47 is realized by retracting the injection piston 37 by the first driving device 29A and pushing out the hydraulic fluid in the head side chamber 35h into the accumulator 47, as will be described in detail later.

A portion of the filling of the accumulator 47 may be performed by retracting the booster piston 41 . For example, the booster piston 41 may be retracted by the second electric motor 31B to push the hydraulic fluid in the rear side chamber 35a to the accumulator 47. And/or, in a part of the interval in which the injection piston 37 is retracted by the first driving device 29A (for example, the initial interval of the retraction), discharge of the hydraulic fluid from the head side chamber 35h is prohibited to retract the pressure intensifying piston 41. , the hydraulic fluid in the rear chamber 35 a may be forced into the accumulator 47 .

However, the filling of the accumulator 47 by the first driving device 29A may be performed only with the hydraulic fluid discharged from the head-side chamber 35h, unlike the description of this embodiment. For example, the hydraulic fluid in the rear side chamber 35a may be discharged to the tank 51 while the pressure intensifying piston 41 is retracted as described above. Further, unlike the description of the present embodiment, the pressure-increasing piston 41 may be retracted by supplying hydraulic fluid to the head-side chamber 35h and/or the front-side chamber 35f by the pump 49.

The pump 49 replenishes the working fluid to the rod side chamber 35r, for example, when the injection piston 37 is retracted by the first driving device 29A. Furthermore, the pump 49 may replenish the hydraulic fluid to the front side chamber 35f when retracting the booster piston 41 . Further, for example, the pump 49 contributes to replenishing the hydraulic fluid in an amount corresponding to the hydraulic fluid leaked in the injection cylinder 27 or the like and/or supplying the hydraulic fluid during maintenance of the injection device 9 .

The injection piston 37 is given a rearward driving force by the first driving device 29A. Therefore, in the mode in which the hydraulic fluid is replenished from the pump 49 to the rod side chamber 35r, the force of the hydraulic fluid in the rod side chamber 35r pushing the injection piston 37 backward is greater than the force pushing the injection piston 37 forward of the hydraulic fluid in the head side chamber 35h. can be small. That is, the product of the pressure in the rod side chamber 35r and the area where the pressure acts on the injection piston 37 is the pressure in the head side chamber 35h (accumulator 47 from another point of view) and the area where the pressure acts on the injection piston 37. may be smaller than the product of

Specifically, for example, the force of the hydraulic fluid in the rod-side chamber 35r pushing the injection piston 37 backward is the force of the hydraulic fluid in the head-side chamber 35h pushing the injection piston 37 forward (the pressure of the accumulator 47 is The pressure when returning to the position before the start of injection may be used as a reference.The same applies in the next paragraph.) may be 2/3 or less, 1/2 or less, 1/5 or less, or 1/10 or less. . Furthermore, the pressure in the rod-side chamber 35r may be equal to the tank pressure (the pressure in the tank 51) and/or the atmospheric pressure, or may be slightly lower than these pressures.

The pressure in the rod-side chamber 35r may be higher than the tank pressure and the atmospheric pressure. In this case, the pump 49 assists the retraction of the plunger 21 by the first driving device 29A. At this time, the force with which the hydraulic fluid in the rod side chamber 35r pushes the injection piston 37 rearward may be appropriately set. For example, the force of the hydraulic fluid in the rod-side chamber 35r pushing the injection piston 37 backward is 1/10 or more, 1/5 or more, or 1/1/10 or more, 1/5 or more, or 1/5 of the force of the hydraulic fluid in the head-side chamber 35h pushing the injection piston 37 forward. It may be 2 or more, or 2/3 or more. The lower bounds in the preceding paragraph may be combined with the lower bounds in this paragraph unless there is a conflict.

Also, in the same manner as described above, the pressure in the front chamber 35f does not need to be increased in the mode in which the hydraulic fluid is replenished from the pump 49 to the front chamber 35f. The pressure or force generated by the hydraulic fluid in the rod-side chamber 35r is explained by replacing the rod-side chamber 35r with the front-side chamber 35f, replacing the head-side chamber 35h with the rear-side chamber 35a, and replacing the injection piston 37 with the boosting piston 41. As such, the pressure or force generated by the hydraulic fluid in the front chamber 35f may be assisted.

As described above, in this embodiment, the filling of the accumulator 47 by the pump 49 is basically not performed. Also, the pressure in the rod side chamber 35r (and the front side chamber 35f) to which hydraulic fluid is supplied from the pump 49 when the injection piston 37 (and the boosting piston 41) is retracted may be low. Therefore, for example, the capacity of the pump 49 (the amount of hydraulic fluid delivered in one cycle) may be reduced compared to a typical hydraulic or known hybrid injection device. Moreover, since the hydraulic fluid is directly supplied between the head side chamber 35h (and the rear side chamber 35a) and the accumulator 47, and the tank 51 is not interposed therebetween, the volume of the tank 51 can be reduced.

The accumulator 47 may be composed of an appropriate type of accumulator such as weight type, spring type, pneumatic type (including pneumatic type), cylinder type, Prada type, and the like. For example, the accumulator 47 is a pneumatic, cylinder-type, or Prada-type accumulator, and pressure is accumulated by compressing the gas (for example, air or nitrogen) held in the accumulator 47 .

The pump 49 may be a rotary pump that discharges working fluid by rotating a rotor, or a plunger pump that discharges working fluid by reciprocating a piston. The pump 49 may be configured by a constant displacement pump in which the discharge amount in one cycle of motion of the rotor or piston is fixed, or may be configured by a variable displacement pump in which the discharge amount is variable. Moreover, although it is sufficient for the pump 49 to be able to discharge the hydraulic fluid in one direction, the structure may be the same as that of a bidirectional (two-way) pump.

Although not shown, the pump 49 is driven by, for example, a rotary electric motor. The electric motor may be a DC motor or an AC motor, an induction motor or a synchronous motor. The electric motor may function as a constant speed electric motor provided in an open loop, or may function as a servomotor provided in a closed loop. The electric motor (pump 49) may be driven only when necessary, or may be driven all the time.

The tank 51 is, for example, an open tank. That is, the tank 51 holds hydraulic fluid under atmospheric pressure. Therefore, for example, when the rod-side chamber 35r is connected to the tank 51, the pressure in the rod-side chamber 35r drops to atmospheric pressure or a pressure close to it.

(Hydraulic circuit)
Hydraulic system 43 includes a hydraulic circuit 53 that controls the flow of hydraulic fluid between injection cylinder 27 , accumulator 47 , pump 49 and tank 51 . Various specific configurations of the hydraulic circuit 53 are possible for realizing the division of roles between the accumulator 47 and the pump 49 as described above. The configuration of the hydraulic circuit 53 shown in FIG. 9 is merely an example.

Below, the hydraulic circuit 53 illustrated in FIG. 9 will be described in the following order. First, the flow path between the accumulator 47 and the head-side chamber 35h will be described. Next, a flow path between the accumulator 47 and the rear side chamber 35a will be described. Next, the flow path between the rod side chamber 35r and the tank 51 will be described. Next, a flow path between the pump 49 and the rod side chamber 35r will be described. After that, other configurations of the hydraulic circuit 53 will be described.

(Flow path between accumulator and head-side chamber)
The hydraulic circuit 53 has a flow path 54a that communicates the accumulator 47 and the head-side chamber 35h. The flow path 54a contributes to, for example, causing the hydraulic fluid to flow from the accumulator 47 to the head-side chamber 35h to advance the injection piston 37. As shown in FIG. Further, the flow path 54a contributes to filling the accumulator 47 by causing the hydraulic fluid to flow from the head-side chamber 35h to the accumulator 47 when the injection piston 37 retreats, for example.

The hydraulic circuit 53 has, for example, a flow control valve 55 and a check valve 59A as valves located in the flow path 54a and capable of permitting and prohibiting the flow of the hydraulic fluid in the flow path 54a.

The flow control valve 55 can control the flow rate of the hydraulic fluid in the channel 54a. By controlling the flow rate of the hydraulic fluid supplied from the accumulator 47 to the head-side chamber 35h, for example, the advancing speed of the injection piston 37 is controlled. That is, the flow control valve 55 constitutes a so-called meter-in circuit.

The flow control valve 55 is, for example, a pressure-compensated flow control valve that can keep the flow constant even if the pressure fluctuates. The flow control valve 55 is, for example, a servo valve that is used in a servomechanism and that can steplessly (continuously, to any value) modulate the flow rate according to an input signal.

The configuration of the flow control valve 55 may be various configurations, for example, it may be a known configuration. In the illustrated example, the flow control valve 55 has a main valve 56 that controls the flow of hydraulic fluid in the flow path 54 a and a pilot valve 57 that controls the operation of the main valve 56 .

The main valve 56 is located in the flow path 54a and directly controls the flow rate of the hydraulic fluid in the flow path 54a. The main valve 56 is, for example, a 2-port 2-position switching valve that continuously switches the flow depending on the position of the valve body. The position of the disc is controlled by pilot pressures introduced on either side of the disc's direction of travel. Also, the position of the valve body is detected by a sensor (for example, a differential transformer).

The pilot valve 57 controls the pilot pressure introduced to both sides of the valve body of the main valve 56 . Specifically, the pilot valve 57 has two ports communicating with both sides (two flow paths 54b) of the valve body of the main valve 56, and two ports communicating with the accumulator 47 (flow path 54c) and the tank 51 (flow path 54d). port. The pilot valve 57 is a 4-port 3-position switching valve that continuously switches the connection between the former two ports and the latter two ports depending on the position of the valve body. The position of the valve body is controlled, for example, by an electromagnetic drive (eg, solenoid).

It should be noted that leakage of hydraulic fluid from each of the main valve 56 and the pilot valve 57 is collected in the tank 51 . The valve disc may be spring-biased into position (as are other valve discs).

The check valve 59A is configured by a check valve that is opened and closed by introducing pilot pressure. The check valve 59A allows the flow from the accumulator 47 to the head side chamber 35h and prohibits the flow in the opposite direction when the pilot pressure is not applied. Therefore, for example, when the hydraulic fluid in the head-side chamber 35h is pressurized by the pressure-increasing piston 41 and the pressure in the head-side chamber 35h becomes higher than the pressure in the accumulator 47, the check valve 59A self-closes.

Introduction of the pilot pressure to the check valve 59A may be done by a switching valve 60A located between the check valve 59A and the accumulator 47, for example. The switching valve 60A has two ports, for example, a port that supplies an open pilot pressure to the check valve 59A, a port that supplies a closed pilot pressure to the check valve 59A, and two ports that communicate with the accumulator 47 and the tank 51. have. The switching valve 60A is a 4-port 2-position switching valve that switches connection between the former two ports and the latter two ports depending on the position of the valve body. The position of the valve body is controlled, for example, by an electromagnetic drive (eg, solenoid).

(Flow path between accumulator and rear side chamber)
The hydraulic circuit 53 has a flow path 54m that communicates the accumulator 47 and the rear chamber 35a. The flow path 54m contributes to, for example, causing the hydraulic fluid to flow from the accumulator 47 to the rear side chamber 35a to advance the pressure boosting piston 41. As shown in FIG. Further, the flow path 54m contributes to filling the accumulator 47 with hydraulic fluid flowing from the rear chamber 35a to the accumulator 47 when the boosting piston 41 moves backward, for example.

The flow path 54m shares a part on the accumulator 47 side with the flow path 54a. However, the flow path 54m may be a flow path separate from the flow path 54a over its entirety.

The flow control valve 55 described above may be positioned in the shared portion of the flow path 54m and the flow path 54a. That is, the flow control valve 55 may be capable of controlling the flow rate of hydraulic fluid flowing from the accumulator 47 to the rear chamber 35a. However, the flow control valve 55 may be arranged at a position of the flow path 54a that is not shared with the flow path 54m.

The hydraulic circuit 53 has, for example, a flow control valve 55 and a check valve 59E as valves located in the flow path 54m and capable of permitting and prohibiting the flow of the working fluid in the flow path 54m. The check valve 59E is configured by, for example, a check valve that is opened and closed by introduction of pilot pressure in the same manner as the check valve 59A. The check valve 59E allows the flow from the accumulator 47 to the rear side chamber 35a and prohibits the flow in the opposite direction, for example, when the pilot pressure is not applied. The configuration for introducing the pilot pressure to the check valve 59E may be the same as the configuration of the check valve 59A, and is not shown in FIG.

(Flow path between rod-side chamber and tank)
The hydraulic circuit 53 has a flow path 54e that communicates the rod side chamber 35r and the tank 51 with each other. For example, the flow path 54e contributes to allowing the injection piston 37 to move forward by allowing the hydraulic fluid in the rod side chamber 35r to flow to the tank 51 when the injection piston 37 advances.

The hydraulic circuit 53 has, for example, a check valve 59B as a valve positioned in the flow path 54e and capable of permitting or prohibiting the flow of hydraulic fluid in the flow path 54e. The configuration of the check valve 59B is similar to that of the check valve 59A, for example. The above description regarding the configuration of the check valve 59A may be applied to the configuration of the check valve 59B as long as there is no contradiction. When the pilot pressure is not applied, the check valve 59B allows the flow from the rod side chamber 35r to the tank 51 and prohibits the flow in the opposite direction.

Introduction of the pilot pressure to the check valve 59B may be done by a switching valve 60B located between the check valve 59B and the accumulator 47, for example. The configuration of the switching valve 60B is, for example, similar to the configuration of the switching valve 60A. The above description regarding the configuration of the switching valve 60A may be applied to the configuration of the switching valve 60B as long as there is no contradiction.

An accumulator 61 may be connected between the rod side chamber 35r and the tank 51 (more specifically, between the check valve 59B and the tank 51, for example). This accumulator 61 contributes to, for example, absorbing the surge pressure generated in the rod side chamber 35r when filling of the molten metal is completed. The above description regarding the configuration of the accumulator 47 may be applied to the configuration of the accumulator 61 as long as there is no contradiction. However, since the accumulator 61 is not used as a drive source, it may be smaller than the accumulator 47, and the pressure that can be accumulated may be lower.

(Flow path between pump and rod-side chamber)
The hydraulic circuit 53 has a flow path 54f that communicates the pump 49 and the rod side chamber 35r. For example, when the injection piston 37 is retracted by the first driving device 29A, the flow path 54f contributes to replenishing the rod side chamber 35r with hydraulic fluid by causing the hydraulic fluid to flow from the pump 49 to the rod side chamber 35r.

The hydraulic circuit 53 has, for example, a switching valve 62 and a check valve 63A as valves positioned in the flow path 54f and capable of permitting and prohibiting the flow of hydraulic fluid in the flow path 54f. In addition, as understood from the following description, the combination of these two valves may be regarded as one valve.

The switching valve 62 is located in the flow path 54h that supplies the hydraulic fluid from the pump 49 to the head-side chamber 35h, and also functions as a valve that permits and prohibits the flow of the hydraulic fluid in the flow path 54h. The supply of hydraulic fluid from the pump 49 to the head-side chamber 35h is, for example, compensation for leaked hydraulic fluid and/or maintenance, as described above.

The switching valve 62 has two ports, a port communicating with the rod-side chamber 35 r and a port communicating with the head-side chamber 35 h, and two ports communicating with the pump 49 and the tank 51 . The switching valve 62 is a 4-port 3-position switching valve that switches connection between the former two ports and the latter two ports depending on the position of the valve body. The position of the valve body is controlled, for example, by an electromagnetic drive (eg, solenoid).

More specifically, the three positions of the switching valve 62 are as follows. At the position on the left side of the drawing, the rod side chamber 35r and the pump 49 are connected, and the head side chamber 35h and the tank 51 are connected. At the position on the right side of the drawing, the rod side chamber 35r and the tank 51 are connected, and the head side chamber 35h and the pump 49 are connected. In the middle position of the figure, neither port is connected. Therefore, for example, by setting the switching valve 62 to the left side of the drawing, it is possible to replenish the hydraulic fluid from the pump 49 to the rod side chamber 35r.

The check valve 63A is located between the rod side chamber 35r and the switching valve 62. The check valve 63A permits flow from the switching valve 62 to the rod side chamber 35r and prohibits flow in the opposite direction. As a result, for example, when the switching valve 62 is positioned on the right side of the drawing in order to supply the working fluid from the pump 49 to the head side chamber 35h, the working fluid in the rod side chamber 35r flows through the switching valve 62 into the tank 51. prohibited from flowing to

Although not particularly illustrated, the switching valve may not be shared between the flow path 54f and the flow path 54h. For example, each flow path may be provided with a 3-port, 3-position switching valve that permits and prohibits the flow of hydraulic fluid, or a pilot-type check valve may be provided.

(Other configurations of the hydraulic circuit)
The hydraulic circuit 53 has a flow path 54h for supplying hydraulic fluid from the pump 49 to the head-side chamber 35h, as described above. The hydraulic circuit 53 has, for example, the switching valve 62 and the check valve 64 as valves positioned in the flow path 54h and capable of permitting and prohibiting the flow of the hydraulic fluid in the flow path 54h.

The check valve 64 is positioned between the head-side chamber 35h and the switching valve 62. The check valve 64 permits flow from the switching valve 62 to the head-side chamber 35h and prohibits flow in the opposite direction. As a result, for example, when the switching valve 62 is set to the left side position in the figure to supply the working fluid from the pump 49 to the rod side chamber 35r, the working fluid in the head side chamber 35h flows into the tank 51 via the switching valve 62. prohibited from flowing to In the illustrated example, the check valve 64 is a pilot type check valve that is closed (prohibits bidirectional flow) by introducing pilot pressure.

Introduction of the pilot pressure of the check valve 64 may be done by the shuttle valve 65, for example. Shuttle valve 65 has two inlets and one outlet. One of the two inlets is connected to the head side chamber 35h side of the check valve 64 of the flow path 54h. The remainder of the two inlets are connected to the accumulator 47 via a switching valve 66 which will be described later. The outlet leads to check valve 64 . The outlet is connected to the high pressure side of the two inlets, and applies the pressure from the connected inlet to the check valve 64 as pilot pressure. This, for example, reduces the likelihood that the check valve 64 will be opened when it is not intended to be opened.

The flow of hydraulic fluid from the accumulator 47 to the shuttle valve 65 may be controlled, for example, by a switching valve 66 located between them. The switching valve 66 has three ports, for example, a port connected to the shuttle valve 65 , a port connected to the accumulator 47 , and a port connected to the tank 51 . The switching valve 66 connects the port leading to the shuttle valve 65 and one of the other two ports depending on the position of the valve body. The position of the valve body is controlled, for example, by an electromagnetic drive (eg, solenoid).

The hydraulic circuit 53 has a channel 54k for supplying hydraulic fluid from the pump 49 to the accumulator 47, for example. As described above, the accumulator 47 is basically filled by retracting the injection piston 37 by the first driving device 29A and pushing out the hydraulic fluid in the head-side chamber 35h to the accumulator 47. The supply of hydraulic fluid from the pump 49 to the accumulator 47 is, for example, in compensating for leaked hydraulic fluid and/or in maintenance.

The hydraulic circuit 53 has, for example, a switching valve 46 as a valve located in the flow path 54k and capable of permitting and prohibiting the flow of the hydraulic fluid in the flow path 54k. The switching valve 46 connects or disconnects the accumulator 47 and the pump 49 or the tank 51 depending on the position of the valve body, for example. The position of the valve body is controlled, for example, by sequentially operating an electromagnetic drive unit and a pilot drive unit (see operation method of flow control valve 55). Pilot pressure may be the pressure from accumulator 47, for example.

In the mode in which the front side chamber 35f is filled with hydraulic fluid, the hydraulic circuit 53 may have a flow path that connects the front side chamber 35f and the tank 51 (pump 49 if necessary), although not shown. The flow path may be provided with a valve that allows and prohibits the flow of hydraulic fluid.

　Hydraulic circuit 53 may have

check valves

63B, 63C and 63D at appropriate positions to allow the flow of hydraulic fluid from pump 49 and prohibit the flow in the opposite direction. Further, the hydraulic circuit 53 may have a check valve (reference numeral omitted) that allows the hydraulic fluid to flow from the switching valve 66 to the tank 51 and prohibits the flow in the opposite direction. Also, the hydraulic circuit may have a cock 58 at an appropriate location. The cock 58 is for maintenance purposes, for example, and is closed when injection is being performed. Various instruments (reference numerals omitted) such as a pressure gauge may be connected to the end of the flow path extending from the cock 58 . The hydraulic circuit 53 may also have a filter 48 and a relief valve 52 at appropriate locations.

(first driving device)
The first driving device 29A shown in FIG. 8 has the first electric motor 31A and the detachable portion 33 that can be connected to and disconnected from the piston rod 39, as described above. 29 A of 1st drive devices are a component for transmitting the driving force of 31 A of 1st electric motors to the piston rod 39, For example, 67 A of 1st transmission mechanisms and 68 A of 1st conversion mechanisms are carried out in order from the 1st electric motor 31A to the attachment or detachment part 33. and a movable member 69 .

The first electric motor 31A is a rotary electric motor. Although not shown, the first electric motor 31A has, as is well known, a stator that constitutes one of the armature and the field system, and a rotor that constitutes the other of the armature and the field system. The rotor rotates about its axis with respect to the stator. A specific configuration of the first electric motor 31A may be appropriately selected. For example, the first electric motor 31A may be a DC motor or an AC motor, an induction motor or a synchronous motor, and may or may not have a brake. The first electric motor 31A is configured as a servo motor, for example, and constitutes a servo mechanism together with a sensor (not shown) that detects the rotation of the first electric motor 31A and a servo driver (not shown) that supplies power to the first electric motor 31A. is doing.

The main body (stator) of the first electric motor 31A is fixed to a stationary portion (for example, the cylinder member 35) of the injection device 9, and various parallel movements and rotational movements are restricted. The arrangement position, orientation, etc. of the first electric motor 31A may be appropriately set. In the illustrated example, the first electric motor 31A is arranged on the side of the injection cylinder 27 and fixed to the rear surface of the plate 45c of the frame 45. As shown in FIG. The first electric motor 31A is arranged such that its output shaft is parallel to the injection cylinder 27 and directed forward.

The first transmission mechanism 67A transmits the rotation of the first electric motor 31A, and contributes, for example, to improving the degree of freedom in the arrangement of the first electric motor 31A and/or speeding up the speed of rotation. The first transmission mechanism 67A is composed of, for example, a pulley and belt mechanism, and includes a first pulley 70A fixed to the output shaft of the first electric motor 31A and a first nut 71A (which is also used by the first conversion mechanism 68A). pulley) and a first belt 72A that is stretched over the first pulley 70A and the first nut 71A. Therefore, when the first electric motor 31A rotates, the rotation is transmitted to the first conversion mechanism 68A via the first transmission mechanism 67A. Either the diameter of the first pulley 70A or the diameter of the first nut 71A may be larger or may be equal. In the illustrated example, the diameter of the first nut 71A is larger than the diameter of the first pulley 70A, and the rotation of the first electric motor 31A is decelerated.

A specific arrangement position of the first transmission mechanism 67A may be set as appropriate. In the illustrated example, the first transmission mechanism 67A is located on the side of the injection cylinder 27 and is arranged inside the plate 45c of the frame 45. As shown in FIG. The first pulley 70A and the first nut 71A are arranged in the lateral direction of the injection cylinder 27 .

The first conversion mechanism 68A contributes to converting the rotary motion of the first electric motor 31A into linear motion (translational motion). 68 A of 1st conversion mechanisms are comprised by the screw mechanism (for example, ball screw mechanism or slide screw mechanism), for example. The first conversion mechanism 68A has a first screw shaft 73A and a first nut 71A screwed onto the first screw shaft 73A via a ball (not shown) or directly. One member of the first screw shaft 73A and the first nut 71A (the first nut 71A in the illustrated example) is, for example, allowed to rotate about its axis and restricted from moving in the axial direction. The other member (the first screw shaft 73A in the illustrated example) is, for example, restricted from rotating about its axis and allowed to move in the axial direction. Therefore, when one member (the first nut 71A) is rotated, the other member (the first screw shaft 73A) is axially driven. A specific configuration of the first conversion mechanism 68A may be set as appropriate. For example, one thread groove may be provided, or two or more thread grooves may be provided. Further, for example, the diameter and lead of the first screw shaft 73A are arbitrary.

The first conversion mechanism 68A is arranged in parallel with the injection cylinder 27. That is, the first screw shaft 73A is parallel to the piston rod 39, and the direction of linear motion of the first conversion mechanism 68A is parallel to the driving direction of the injection cylinder 27 (front-rear direction). The specific arrangement position of the first conversion mechanism 68A, the method of restricting the parallel movement of the first nut 71A, the method of restricting the rotation of the first screw shaft 73A, and the like may be appropriately set. In the illustrated example, the first conversion mechanism 68A is positioned on the side of the injection cylinder 27 and positioned closer to the injection cylinder 27 than the first electric motor 31A. The first nut 71A is arranged inside the plate 45c of the frame 45, and is supported by the plate 45c by a bearing (not shown) so as to allow only rotation. Rotation of the first screw shaft 73A is restricted by being connected to a movable member 69 that is only allowed to move in parallel in the front-rear direction.

The movable member 69 is a member that is driven in the front-rear direction by the driving force of the first electric motor 31A, and contributes to transmitting the driving force of the first electric motor 31A to the plunger 21 and to supporting the detachable portion 33. there is Note that the movable member 69 may be regarded as part of the detachable portion 33 . The shape, size and material of the movable member 69 are arbitrary. In the illustrated example, the movable member 69 is a member shared by the two first driving devices 29A (see also FIG. 7), extends in the horizontal direction of the injection cylinder 27 (vertical direction in FIG. 8), It is shaped to have a hole through which the piston rod 39 is inserted. In addition, the movable member 69 is generally shaped like a plate facing in the front-rear direction.

The first driving device 29A may have a guide mechanism for guiding the movable member 69 in the front-rear direction (from another point of view, restricting movements other than parallel movement in the front-rear direction). In the examples of FIGS. 7 and 8, a pair of guide shafts 74 are illustrated as the guide mechanism. The pair of guide shafts 74 extend in the front-rear direction and are fixed to the frame 45 . A pair of guide shafts 74 are inserted through the movable member 69 so that only forward and backward movement is permitted. 6 also illustrates a linear guide 75 that supports and guides the movable member 69 from below.

The detachable portion 33 shown in FIG. 8 is supported by the movable member 69 and moves in the front-rear direction together with the movable member 69 . The detachable portion 33 connects and disconnects the movable member 69 and a predetermined portion (removable portion 39z) of the piston rod 39 . The detachable portion 39z is positioned outside the cylinder member 35 regardless of the position of the injection piston 37, for example. That is, even when the injection piston 37 is positioned at the retraction limit due to rear contact with a stopper (not shown) inside the cylinder member 35, the detachable portion 39z is positioned outside the cylinder member 35. As shown in FIG.

By connecting the movable member 69 and the detachable part 39z, the plunger 21 can be retracted by the driving force of the first electric motor 31A, for example. Further, by releasing the connection between the movable member 69 and the piston rod 39, for example, when the hydraulic fluid is supplied to the head-side chamber 35h to advance the plunger 21 at high speed, the inertial force of the first driving device 29A causes The speed reduction of the plunger 21 is avoided.

The detachable portion 33 has, for example, an engaging member 76 that can be engaged with the detachable portion 39z of the piston rod 39 and an actuator 77 that drives the engaging member 76 . The engaging member 76 is supported by the movable member 69 so as to be movable between an engaging position where it engages with the detachable portion 39z in the front-rear direction and a release position (position in FIG. 8) where the engagement is released. It is The actuator 77 moves the engaging member 76 between the engaging position and the releasing position.

The specific shapes of the engaging member 76 and the detachable portion 39z may be set as appropriate. In the illustrated example, the detachable portion 39z has a small diameter portion 39a, a first large diameter portion 39b and a second large diameter portion 39c. The first large diameter portion 39b is located behind the small diameter portion 39a and has a larger diameter than the small diameter portion 39a. The second large diameter portion 39c is positioned in front of the small diameter portion 39a and has a larger diameter than the small diameter portion 39a. The engaging member 76 is inserted between the first large-diameter portion 39b and the second large-diameter portion 39c to engage them rearwardly or forwardly. Further, the engaging member 76 is disengaged by retreating from between the first large diameter portion 39b and the second large diameter portion 39c.

In the illustrated example, the diameters of the first large diameter portion 39b and the second large diameter portion 39c are the same as the diameter of most of the piston rod 39. That is, a small-diameter portion 39a is formed by reducing the diameter of a part of the piston rod 39. As shown in FIG. However, for example, the diameter of the small-diameter portion 39 a may be the same as the diameter of most of the piston rod 39 . The first large diameter portion 39b and the second large diameter portion 39c may be formed by flanges. Unlike the illustrated example, the first large diameter portion 39b and the second large diameter portion 39c may have different diameters.

Although not shown, the engagement member 76 may have a recess on the side of the small diameter portion 39a when viewed in the axial direction of the piston rod 39. The recess accommodates, for example, at least part of the small diameter portion 39a when the engaging member 76 is moved to the engaging position. By providing such a concave portion, for example, the amount of mutual engagement between the engaging member 76 and the first large diameter portion 39b (second large diameter portion 39c) can be adjusted with respect to the angular range of the small diameter portion 39a around the axis. You can make it bigger. The specific shape and dimensions of the recess may be set as appropriate. For example, a concave portion formed in one engaging member 76 has a semicircular shape in which the small diameter portion 39a is generally fitted. The two engaging members 76 engage the first large diameter portion 39b over the entire circumference of the small diameter portion 39a.

The configuration of the actuator 77 may be made appropriate. In the illustrated example, the actuator 77 is a combination of a spring and a pneumatic cylinder, although no particular reference numeral is attached. Specifically, the actuator 77 includes a cylinder chamber formed within the movable member 69, a piston slidable in the cylinder chamber, and a piston rod extending from the piston and connected to the engaging member 76. have. The spring, for example, biases the piston in a direction in which the engagement member 76 is disengaged. The engagement member 76 is moved from the disengaged position to the engaged position by supplying gas (eg, air) to the side of the piston opposite the piston rod. Other examples of actuators 77 include, for example, linear motors or hydraulic cylinders.

The arrangement position of the first driving device 29A may be set as appropriate. In the illustrated example, the two first driving devices 29A are arranged line-symmetrically with respect to the injection cylinder 27 when viewed from above. Also, the two first driving devices 29A are positioned at the same height as the injection cylinder 27 in the vertical direction, for example. More specifically, for example, the axial centers of the two first screw shafts 73A and the piston rod 39 may be positioned at the same height in the vertical direction.

As described above, the first driving device 29A retracts the plunger 21 after injection is completed. Therefore, the first driving device 29A is configured to be able to move the attaching/detaching portion 33 with a stroke equal to or greater than the intended stroke of the plunger 21 . The stroke of the first driving device 29A and the stroke of the injection cylinder 27 may be equal, or one may be greater than the other.

(Second driving device)
The second drive device 29B includes the second electric motor 31B and drives the pressure boosting piston 41 as described above. As components for transmitting the driving force of the second electric motor 31B to the pressure-increasing piston 41, the second driving device 29B includes, for example, a second transmission mechanism 67B and a second transmission mechanism 67B and a second conversion mechanism 67B in order from the second electric motor 31B to the pressure-increasing piston 41. It has a mechanism 68B.

The second electric motor 31B is a rotary electric motor like the first electric motor 31A. The above description regarding the configuration of the first electric motor 31A may be incorporated into the configuration of the second electric motor 31B as long as there is no contradiction. The second electric motor 31B may be the same or different in type (eg, AC or DC, and/or induction or synchronous) from the first electric motor 31A. Further, the second electric motor 31B may differ from the first electric motor 31A in performance (rated torque, etc.) according to the difference in roles between the first driving device 29A and the second driving device 29B.

The main body (stator) of the second electric motor 31B is fixed to a stationary portion (for example, the cylinder member 35) of the injection device 9, and various parallel movements and rotational movements are restricted. The arrangement position, orientation, etc. of the second electric motor 31B may be appropriately set. In the example of FIG. 6 , the second electric motor 31B is arranged behind and below the injection cylinder 27 . In addition, in the example of FIG. 8, the second electric motor 31B is arranged so that the output shaft is parallel to the injection cylinder 27 and directed rearward.

The second transmission mechanism 67B transmits the rotation of the second electric motor 31B in the same manner as the first transmission mechanism 67A that transmits the rotation of the first electric motor 31A. The above description regarding the configuration of the first transmission mechanism 67A may be incorporated into the configuration of the second transmission mechanism 67B as long as there is no contradiction. When incorporated, the term first pulley 70A is replaced with the term second pulley 70B, the term first nut 71A is replaced with the term second nut 71B, and the term first belt 72A is replaced with the term second belt 72B. word. The second transmission mechanism 67B may differ from the first transmission mechanism 67A in gear ratio and the like according to the difference in role between the first drive device 29A and the second drive device 29B.

A specific arrangement position of the second transmission mechanism 67B may be set as appropriate. In the illustrated example, the second transmission mechanism 67B is positioned behind the injection cylinder 27 . The second nut 71B is arranged coaxially with the injection cylinder 27 . The second pulley 70B is positioned below the second nut 71B (see the position of the second electric motor 31B in FIG. 6).

The second conversion mechanism 68B converts the rotary motion of the second electric motor 31B into linear motion, similar to the first conversion mechanism 68A that converts the rotary motion of the first electric motor 31A into linear motion. The above description of the configuration of the first conversion mechanism 68A may be incorporated into the configuration of the second conversion mechanism 68B as long as there is no contradiction. When using, the term of the first nut 71A is replaced with the term of the second nut 71B, and the term of the first screw shaft 73A is replaced with the term of the second screw shaft 73B. The specific configurations of the first conversion mechanism 68A and the second conversion mechanism 68B may differ according to the difference in role between the first drive device 29A and the second drive device 29B. For example, both may differ in type (for example, whether it is a ball screw mechanism or slide screw mechanism), diameter and/or lead. In the illustrated example, the length of the second screw shaft 73B is shorter than the length of the first screw shaft 73A.

The second conversion mechanism 68B is arranged coaxially with the injection cylinder 27, for example. The second screw shaft 73B is connected to the booster piston 41 and restricted from rotating. The second nut 71B is allowed to rotate around its axis, and other movements are restricted. Therefore, when the second electric motor 31B rotates the second nut 71B, the second screw shaft 73B moves in the axial direction, and thus the pressure boosting piston 41 moves in the front-rear direction.

A method for restricting parallel movement of the second nut 71B and a method for restricting rotation of the second screw shaft 73B may be appropriate. For example, the second nut 71B may be supported via a bearing by an appropriate member connected to the cylinder member 35, thereby allowing rotation while restricting other movements. Further, for example, the second screw shaft 73B may be allowed to move in the axial direction and restricted from rotating around the axis by the spline groove.

(other configuration of die casting machine)
The die casting machine 1 may have various sensors that detect various physical quantities related to the operation of the machine body 3 . Then, the control device 5 may control the hydraulic device 43, the first electric motor 31A, the second electric motor 31B, and the attaching/detaching portion 33 (actuator 77) based on the detection values of various sensors.

An example of the above sensor is given. For example, a position sensor 99 (FIG. 8) that detects the position of the piston rod 39 (plunger 21), a pressure sensor (not shown) that detects the pressure of the accumulator 47, and a pressure sensor 97H (FIG. 9) that detects the pressure of the head side chamber 35h. ), a pressure sensor 97R (FIG. 9) for detecting the pressure in the rod-side chamber 35r, a sensor (not shown) for detecting the position of the movable member 69, and a sensor (not shown) for detecting the number of revolutions (rotational speed) of the first electric motor 31A. ), a sensor (not shown) for detecting the position of the boosting piston 41, a sensor (not shown) for detecting the rotation speed of the second electric motor 31B, a sensor (not shown) for detecting the torque of the first electric motor 31A, and/or Alternatively, a sensor (not shown) that detects the torque of the second electric motor 31B may be provided.

The position sensor can be regarded as a speed sensor because the speed (or number of rotations) can be obtained by differentiating the position (or rotational position). Similarly, a sensor that detects the number of rotations may be regarded as a sensor that detects rotational position. The various sensors may have various configurations, for example, may have known configurations. For example, sensors that detect the positions of the piston rod 39, the movable member 69, and the booster piston 41 may be linear encoders or laser length meters. A sensor that detects rotation may be an encoder or a resolver. A sensor that detects torque may utilize a strain gauge. A current detector that detects the current flowing through the motor may also be regarded as a torque sensor.

(Operation of injection device)
10A and 10B are diagrams for explaining the operation of the injection device 9. FIG.

In FIG. 10, the horizontal axis indicates time t. A solid line Lv indicates changes in the injection speed (the speed of the plunger 21), and a broken line Lp indicates changes in the injection pressure (for example, the pressure applied to the molten metal by the plunger 21). In the graph on which the solid line Lv and the dashed line Lp are drawn, the vertical axis indicates the magnitude of the injection speed V and the injection pressure P.

In the lower part of FIG. 10, operations of the accumulator 47 (abbreviated as "ACC"), the first electric motor 31A, the second electric motor 31B, and the attachment/detachment section 33 are shown.

In "ACC", "release 1" indicates a state in which the working fluid is released (mainly) from the accumulator 47 to the head-side chamber 35h. “Discharge 2” indicates a state in which hydraulic fluid is discharged from the accumulator 47 (mainly) to the rear chamber 35a. "Filling" indicates a state in which the accumulator 47 is filled with the hydraulic fluid in the head side chamber 35h or the rear side chamber 35a. "Stop" indicates a condition in which any of the above hydraulic fluid flows are inhibited.

In the "first electric motor" and the "second electric motor", "forward rotation" indicates a state in which the detachable portion 33 or the boosting piston 41 rotates in the forward direction. "Reverse" indicates a state in which rotation is performed in the direction opposite to the above. "Stop" indicates a state in which rotation is not performed. It should be noted that, unless otherwise specified, the electric motor may be stopped in any one of a torque-free state, a position-controlled state, and a brake-operated state, for example.

In "detachment", "ON" indicates that the detachable portion 33 is connected to the piston rod 39. "OFF" indicates a state in which the connection is released.

In "ACC", "first electric motor", "second electric motor" and "detachment", dashed lines indicate operations of modified examples described later. See the solid line here.

For example, the injection device 9 performs low-speed injection (time points t0 to t1), high-speed injection (time points t1 to t3), pressure increase (time points t4 to t6), and pressure holding (time points t6 to t7) in sequence. That is, in the initial stage of injection, the injection device 9 performs low-speed injection in which the plunger 21 advances at a relatively low speed (velocity V _L ) from the viewpoint of preventing entrainment of air in the molten metal. Next, the injection device 9 performs high-speed injection by moving the plunger 21 forward at a relatively high speed (velocity V _H ) in order to fill the molten metal without delaying the solidification of the molten metal. Next, the injection device 9 increases the pressure of the molten metal in the cavity 107 to the casting pressure P _E (final pressure) by the forward force of the plunger 21 from the viewpoint of eliminating sink marks in the molded product. After that, the injection device 9 performs holding pressure to maintain the casting pressure _PE .

Low-speed ejection and high-speed ejection are performed by supplying hydraulic fluid from the accumulator 47 to the head-side chamber 35h (see "Ejection 1" of ACC in the figure). The pressure increase is initially performed by supplying hydraulic fluid from the accumulator 47 to the head-side chamber 35h. These operations correspond, for example, to FIGS. The rest of the process of increasing pressure and holding pressure are performed by supplying hydraulic fluid (applying pressure) from the accumulator 47 to the rear chamber 35a (see "Release 2" of ACC in the figure). These operations correspond to FIGS. 4 and 5. FIG. Specifically, it is as follows.

(Low speed injection: t0 to t1)
Immediately before the start of low-speed injection, the injection device 9 is in the state shown in FIGS. 1 and 6-9. That is, the injection piston 37 and the boosting piston 41 are positioned at initial positions such as the retraction limit. The connection (engagement) of the detachable portion 33 is released. The various valves in the hydraulic circuit 53 are, for example, controlled to basically prohibit the flow of hydraulic fluid. The first electric motor 31A, the second electric motor 31B and the pump 49 (the electric motor for driving the pump 49) are stopped. As described above, the motor may be stopped in an appropriate state. For example, at least one of these electric motors (for example, the second electric motor 31B) may be in a torque-free state from the viewpoint of reducing power consumption.

The control device 5 determines whether or not a predetermined injection start condition has been met. The injection start condition may be, for example, that the mold clamping of the fixed mold 103 and the movable mold 105 is completed and information indicating that the molten metal has been supplied to the sleeve 19 is obtained. Then, when the control device 5 determines that the injection start condition is satisfied, it starts injection (low-speed injection).

Specifically, the control device 5 opens the flow control valve 55 and the check valve 59A. As a result, the hydraulic fluid is supplied from the accumulator 47 to the head-side chamber 35h. Also, the control device 5 opens the check valve 59B. This allows the hydraulic fluid to be discharged from the rod-side chamber 35r. Then, the injection piston 37 moves forward while discharging the hydraulic fluid in the rod side chamber 35r by the pressure received from the head side chamber 35h. Consequently, the piston rod 39 and plunger 21 move forward.

The speed of the plunger 21 is controlled by adjusting the flow rate of the hydraulic fluid supplied to the head-side chamber 35h by the flow rate control valve 55. Specifically, the control device 5 feedback-controls the opening of the flow control valve 55 so that the speed of the plunger 21 detected by the position sensor 99 converges to the target speed. This feedback control may be, for example, a feedback control of the speed itself, or a substantial speed feedback control that is performed so that the detected position of the plunger 21 becomes the target position every moment. may be feedback control. The speed of the plunger 21 is, for example, low (less than 1 m/s) and constant. However, multistage control of the speed of the plunger 21 may be performed.

The controller 5 disconnects the detachable part 33 from the piston rod 39 when the low-speed injection is being performed. Therefore, the speed of the piston rod 39 is not affected by the driving state of the first electric motor 31A. In the illustrated example, the first electric motor 31A is stopped at the start of injection. Therefore, the piston rod 39 (detachable portion 39z) moves forward while leaving the detachable portion 33 (movable member 69) behind.

(Advancement of detachable part)
The control device 5 starts the forward rotation of the first electric motor 31A at an appropriate time to move the detachable portion 33 forward. The start timing of forward rotation and the speed of forward rotation may be set as appropriate. However, in the illustrated example, the forward rotation start timing and forward rotation speed are such that the attachment/detachment portion 33 reaches the plunger 21 by the time point when it becomes necessary to engage the attachment/detachment portion 33 with the plunger 21 (time point t11 in the illustrated example). is set to reach a position (small diameter portion 39a) that can be connected to .

An example of the forward rotation start timing and the forward rotation speed of the first electric motor 31A will be given. The start timing of forward rotation may be before the start of injection (before time t0), at the start of injection (time t0), during low speed injection (example shown), during high speed injection, or after high speed injection. Further, the speed of the attaching/detaching portion 33 driven by the forward rotation of the first electric motor 31A is lower than the high speed injection speed _VH . Also, the speed may be lower than, equal to, or higher than the low speed injection speed _VL .

As can be understood from the various examples of the start timing and speed described above, unlike the above description, the detachable portion 33 may temporarily or always precede the detachable portion 39z of the piston rod 39. I do not care.

(High-speed injection: t1-t3)
When the predetermined high-speed start condition is satisfied, the controller 5 increases the opening of the flow control valve 55 to increase the flow rate of the hydraulic fluid from the accumulator 47 to the head-side chamber 35h, thereby increasing the speed of the plunger 21. The control at this time, for example, may be the same as the control at the time of low-speed injection, except that the target speed is different. A high speed start condition may be, for example, that the position of the plunger 21 has reached a predetermined high speed switching position. For example, the control device 5 may determine whether or not the detected position of the plunger 21 has reached the high speed switching position to switch the target speed, or may switch the target speed from time to time set based on the high speed switching position and the target speed. It may be just to achieve the target position.

(Deceleration injection: t3-t4)
When the molten metal fills the cavity 107 to some extent, the plunger 21 receives reaction force from the filled molten metal and is decelerated, while the injection pressure rises rapidly. Note that the operation of each part is the same as during high-speed injection. However, deceleration control may be performed to reduce the degree of opening of the flow control valve 55 . Such deceleration control reduces, for example, the impact during filling.

(Pressure increase due to supply of hydraulic fluid to head-side chamber: t4 to t5)
The control device 5 controls the hydraulic circuit 53 to start pressure increase when a predetermined pressure increase start condition is satisfied. The pressure increase start condition is, for example, when the injection pressure reaches a predetermined pressure based on the detection value of the pressure sensor 97H that detects the pressure in the head-side chamber 35h (and the pressure sensor 97R that detects the pressure in the rod-side chamber 35r if necessary). or that the detected position of the plunger 21 detected by the position sensor 99 has reached a predetermined position.

The control device 5 performs speed control based on the detection value of the position sensor 99 (the detection value of the injection speed) from low-speed injection to deceleration injection. On the other hand, when the pressure increase starts, the control device 5 performs pressure control based on the detection value (the injection pressure detection value) of the pressure sensor 97H (and the pressure sensor 97R if necessary). In the pressure control, the control device 5 feedback-controls the flow control valve 55 so that the detected value of the injection pressure rises along a predetermined pressure increase curve, for example.

(Preparation for pressure increase by pressure increase piston: before t5)
The control device 5 controls the hydraulic circuit 53 and the second electric motor 31B so as to perform the operations described with reference to FIG. 3 at appropriate times. That is, the control device 5 prepares for pressure increase by the pressure increase piston 41 (FIG. 4).

Specifically, the control device 5 opens the check valve 59E to allow the hydraulic fluid to flow from the accumulator 47 to the rear side chamber 35a. As a result, the pressure-increasing piston 41 receives rearward pressure from the hydraulic fluid in the head-side chamber 35h and forward pressure from the hydraulic fluid in the rear-side chamber 35a. Both pressures are pressures from the accumulator 47 and are theoretically the same. On the other hand, the pressure-increasing piston 41 has a larger pressure-receiving area in the rear-side chamber 35a than in the head-side chamber 35h. Therefore, the force that the pressure intensifying piston 41 receives from the hydraulic fluid is a forward force as a whole.

On the other hand, the control device 5 controls the second electric motor 31B so as to apply a rearward driving force to the pressure-increasing piston 41 . The magnitude of the backward force applied to the pressure intensifying piston 41 by the second electric motor 31B is, relative to the magnitude of the forward force applied to the pressure intensifying piston 41 by the hydraulic fluid in the head-side chamber 35h and the rear-side chamber 35a, equal or higher. As a result, the pressure-increasing piston 41 is kept stopped at the retraction limit.

Electric power is supplied to the second electric motor 31B so as to generate a rotational driving force that moves the pressure boosting piston 41 backward. However, the second electric motor 31B does not rotate (reverse rotation) in the above rotation direction, and either stops (FIG. 3) or rotates forward (FIG. 4). Therefore, in FIG. 10, "reverse rotation" indicating the operation of the second electric motor 31B near time t5 is written in parentheses.

From the viewpoint of reliably stopping the pressure-increasing piston 41, the rearward force of the second electric motor 31B may be made larger than the forward force of the hydraulic fluid in the head-side chamber 35h and the rear-side chamber 35a. The difference may be set appropriately. The larger the difference between the two forces, the more reliably the intensifying piston 41 can be stopped, while the smaller the difference between the two forces, the easier it is to reduce the power consumption of the second electric motor 31B. For example, the backward force by the second electric motor 31B may be 1.5 times or less, 1.2 times or less, or 1.1 times or less than the forward force by the hydraulic fluid.

The timing to start supplying the hydraulic fluid to the rear side chamber 35a and the timing to start driving the second electric motor 31B may be, for example, substantially the same. From the viewpoint of reliably preventing the advance of the pressure intensifying piston 41, the latter may be faster than the former. The difference between the two timings in this case may be set as appropriate. The larger the difference between the two timings, the more reliably the pressure-increasing piston 41 can stop advancing, while the smaller the difference between the two timings, the easier it is to reduce the power consumption of the second electric motor 31B. For example, when the timing to start driving the second electric motor 31B is earlier than the timing to start supplying hydraulic fluid to the rear chamber 35a, the difference between the two may be 50 msec or less, 20 msec or less, or 10 msec or less.

In the description of the present embodiment, the timing of starting the supply of hydraulic fluid to the rear side chamber 35a is determined by outputting a control command to the hydraulic circuit 53 (a valve (not shown) that controls the pilot pressure to the check valve 59E). It may be the timing, or the timing when the hydraulic fluid is actually supplied to the rear side chamber 35a (which has a control delay with respect to the timing of outputting the control command). In the description of the present embodiment, the timing to start driving the second electric motor 31B is either the timing to output a control command to the second electric motor 31B or the timing to actually start driving the second electric motor 31B. good too. However, in general, the difference between the two can be ignored.

The timing of starting preparation for pressure increase by the pressure-increasing piston 41 (the timing of starting the supply of hydraulic fluid to the rear chamber 35a and/or the timing of starting the driving of the second electric motor 31B) may be an appropriate timing. . The closer the preparation start timing is to the pressure increase start timing by the pressure increase piston 41, the easier it is to reduce the power consumption of the second electric motor 31B. For example, the preparation start timing may be after time t2, after time t3, or after time t4. In the illustrated example, the preparation start timing is set within a period from time t3 to time t5. The period is, in other words, the period from the start of deceleration to the completion of pressure increase by supplying the hydraulic fluid to the head-side chamber 35h. Also, the preparation start timing may be set to be before time t5 and set so that the time difference from time t5 is a predetermined length of time (for example, 100 msec). It should be noted that if power consumption is ignored, the timing of starting the preparation may be earlier than the various points of time exemplified above.

The control of the second electric motor 31B when the pressure intensifying piston 41 is stopped as described above may be, for example, torque control. Specifically, the control device 5 may perform torque control of the second electric motor 31B so that a constant torque is maintained. The control may be feedback control based on a sensor that detects the torque of the second electric motor 31B, or may be open control without feedback. The control of the second electric motor 31B while the pressure intensifying piston 41 is stopped may be position control or speed control.

(Pressure increase by booster piston: t5-t6)
The controller 5 closes the flow control valve 55 and the check valve 59A when a predetermined pressure increase switching condition is satisfied. As a result, backflow of the hydraulic fluid from the head-side chamber 35h to the accumulator 47 is prohibited. In addition, as described with reference to FIG. 4, the control device 5 causes the hydraulic fluid to apply the force that the second electric motor 31B applies to the pressure-increasing piston 41 rearward to the pressure-increasing piston 41. less than the forward force As a result, the pressure in the head-side chamber 35h is increased, and the pressure is increased.

The check valve 59A may be self-closed by the pressure of the hydraulic fluid in the head-side chamber 35h. Specifically, when the injection piston 37 is moving forward, the volume of the head-side chamber 35h is increased, the pressure of the head-side chamber 35h is lower than the pressure of the accumulator 47, and the check valve 59A does not self-close. After that, when the cavity 107 is mostly filled with the molding material and the expansion of the volume of the head side chamber 35h is almost stopped, the pressure of the head side chamber 35h becomes higher than the pressure of the accumulator 47 due to the pressure increasing action of the pressure increasing piston 41. As a result, the check valve 59A self-closes.

The pressure increase switching condition is, for example, when the injection pressure reaches a predetermined pressure based on the detection value of the pressure sensor 97H that detects the pressure in the head side chamber 35h (and the pressure sensor 97R that detects the pressure in the rod side chamber 35r if necessary). or that the detected position of the plunger 21 detected by the position sensor 99 has reached a predetermined position. In other words, the condition may be the same as the pressure increase start condition, but the specific pressure or position used as the determination criterion may be different from the pressure increase start condition.

The control when the pressure is increased by the second electric motor 31B is, for example, pressure control based on the detection value (the injection pressure detection value) of the pressure sensor 97H (and the pressure sensor 97R if necessary). The control device 5, for example, feedback-controls the second electric motor 31B so that the detected value of the injection pressure increases along a predetermined pressure increase curve. This causes the injection pressure to reach the casting pressure P _E (final pressure).

The shape of the boost curve is arbitrary. In the illustrated example, the line indicating the injection pressure before time t5 and the line indicating the injection pressure after time t5 are linear with the same slope (rate of change). This is just one example. Unlike the illustrated example, the booster curve may be curved with a gradually decreasing slope before and after time t5. can be different.

When the pressure is controlled by the second electric motor 31B, the pressure applied from the accumulator 47 to the rear side chamber 35a is, for example, constant. In the description here, the pressure drop due to the discharge of the hydraulic fluid from the accumulator 47 to the rear side chamber 35a is ignored. Specifically, for example, the control device 5 applies constant pressure to the rear chamber 35a by maintaining the opening degree of the flow control valve 55 constant. As a result, the pressure control is not a combination of hydraulic control and electric control, but only electric control, thereby improving control accuracy. However, electric control may be combined with hydraulic control.

In pressure control, the force that the second electric motor 31B applies to the pressure boosting piston 41 to the rear is finally made zero. For example, the control device 5 finally places the second electric motor 31B in a torque-free state (a state in which no electric power is supplied and no driving force is generated). Therefore, the casting pressure P _E is determined by two factors, for example, the pressure of the accumulator 47 and the pressure increase ratio of the booster piston 41 (the ratio of the pressure receiving area in the head side chamber 35h and the pressure receiving area in the rear side chamber 35a). Therefore, the desired casting pressure _PE can be achieved by setting the pressure of the accumulator 47 to an arbitrary pressure before starting injection.

Unlike the present embodiment, the second electric motor 31B may apply a rearward force to the booster piston 41 when the casting pressure _PE is reached. Here, unlike the present embodiment, consider a comparative example in which the casting pressure P _E is obtained by applying a forward force to the booster piston 41 by the second electric motor 31B without supplying hydraulic fluid to the rear side chamber 35a. . In this embodiment, the absolute value of the force that the second electric motor 31B _{applies to the booster piston 41 to obtain the casting pressure P E} _in the comparative example is the same as the second electric motor 31B may be smaller than the absolute value of the force applied forward to the pressure boosting piston 41 . From another point of view, when the casting pressure _PE is reached, the force that the second electric motor 31B applies backward to the pressure boosting piston 41 is less than half the force that the accumulator 47 applies forward to the pressure boosting piston 41. may be assumed.

Further, unlike the present embodiment, the force applied to the pressure-increasing piston 41 by the second electric motor 31B may be changed from the rearward force to the forward force during the pressure control process. Finally, both the forward force of the hydraulic fluid and the forward force of the second electric motor 31B may be applied to the boosting piston 41 to obtain the casting pressure _PE . In this case, the force applied forward by the second electric motor 31B to the booster piston 41 in order to obtain the casting pressure P _E is, of course, the second electric motor 31B in order to obtain the casting pressure P _E in the comparative example. 31B is smaller than the forward force applied to the pressure boosting piston 41 .

Further, unlike the present embodiment, discharge of the hydraulic fluid from the rod side chamber 35r may be prohibited at an appropriate time before the pressure increase is completed. In other words, the final pressure in the rod-side chamber 35r may not be the tank pressure. In this case, the pressure of the hydraulic fluid in the rod side chamber 35r (from another point of view, the timing of prohibiting discharge of the hydraulic fluid from the rod side chamber _35r ) is added to the factor that determines the casting pressure PE.

In this embodiment, the pressure increase start condition and the pressure increase switching condition are set so that the initial part of the pressure increase process is performed by supplying the hydraulic fluid from the accumulator 47 to the head side chamber 35h. However, the entire pressure increasing process is performed only by the action of the pressure increasing piston 41 (pressure control based on the pressure sensor is not performed while hydraulic fluid is being supplied from the accumulator 47 to the head side chamber 35h). The start condition and the pressure increase switching condition may be integrated.

Unlike the present embodiment, the timing at which the flow control valve 55 and the check valve 59A are closed and the timing at which the control device 5 starts pressure control by the second electric motor 31B may be earlier or later. In other words, the conditions for closing the flow control valve 55 and the check valve 59A may differ from the conditions for starting the pressure control by the second electric motor 31B.

(Holding pressure: t6-t7)
When the casting pressure _PE is obtained as described above, the control device 5 controls the hydraulic pressure device 43 and the second electric motor _31B so as to maintain the casting pressure PE. That is, holding pressure is performed. Specifically, for example, the second electric motor 31B is maintained in a torque-free state. Also, the application of pressure from the accumulator 47 to the rear side chamber 35a is continued. In addition, in the description of the pressure increase by the pressure increasing piston 41, the modification examples for obtaining the casting pressure P _E without making the second electric motor 31B torque-free were also described _. The state when was obtained may be maintained.

The molten metal in the cavity 107 is cooled and solidified while the holding pressure is being performed. When the control device 5 determines that the molten metal has solidified (time t7), the control device 5 controls the hydraulic device 43 (and the second electric motor 31B) to end pressure holding. For example, the control device 5 closes the flow control valve 55 and the check valve 59E to prohibit the hydraulic fluid from flowing from the accumulator 47 to the rear chamber 35a. The controller 5 may suitably determine whether the molten metal has solidified. For example, the control device 5 determines whether or not the molten metal has solidified based on whether or not a predetermined time has elapsed from a predetermined time such as time t6 when the final pressure was obtained.

(Arrival of detachable part)
The speed of the plunger 21 decreases due to the decelerated injection and the increased pressure, and the pressure holding starts to stop the plunger 21 . Therefore, the detachable portion 33 driven by the first electric motor 31A catches up with the detachable portion 39z of the piston rod 39. As shown in FIG. In other words, the detachable portion 33 can be connected to the detachable portion 39z.

The control device 5 detects that the detachable portion 33 (movable member 69) has reached a predetermined stop position based on the detection value of the sensor that detects the position of the detachable portion 33 (movable member 69) or the sensor that detects the rotation of the first electric motor 31A. When detected, the first electric motor 31A is stopped. The stop position is, for example, the position of the attachment/detachment section 33 (the position where the attachment/detachment section 33 can be connected) when the attachment/detachment section 33 is connected to the attachment/detachment section 39z (time t11 in the illustrated example), or a position in the vicinity thereof. is.

As described above, the detachable portion 33 reaches the stop position in the illustrated example before the point in time when connection becomes necessary (time t11 in the illustrated example). The specific time may be an appropriate time. For example, the timing may be during deceleration injection, during pressure increase, during pressure retention (example shown), or after completion of pressure retention (but before connection).

(Protruding operation: t9-t10)
After the holding pressure is completed, the control device 5 controls the mold clamping device 7 to move the movable mold 105 away from the fixed mold 103 to open the mold. A molded article formed by solidifying the molten metal leaves one of the fixed mold 103 and the movable mold 105 and remains in the other mold. After that (or at the same time as the mold is opened), the control device 5 controls an extrusion device (not shown) so as to extrude the molded product from the other mold.

When the molded product is separated from the fixed mold 103 as the one mold by mold opening by the mold clamping device 7, or when the molded product is pushed out from the fixed mold 103 as the other mold by the extrusion device, the control device 5 may control the injection device 9 so that the plunger 21 performs an operation of pushing out the molded product from the fixed mold 103 (hereinafter sometimes referred to as "projection operation").

Specifically, for example, the control device 5 rotates the second electric motor 31B forward, and pressurizes the working fluid in the head-side chamber 35h by the pressure-increasing piston 41. The control at this time may be speed control or torque control. For example, the control device 5 controls the speed based on the detected speed of the plunger 21 so that the speed of the plunger 21 is the same as the speed of the moving mold 105 or the speed of the extrusion pin of the extrusion device (not shown). you can go

(Plunger retreat: t11~)
As described above, the attachment/detachment portion 33 stops at (or near) a position where it can be connected to the attachment/detachment portion 39z of the piston rod 39 . When the projecting operation is completed, the control device 5 connects the detachable portion 33 to the detachable portion 39z. At this time, the position of either one of the detachable portion 33 and the detachable portion 39z may be finely adjusted so that the detachable portion 33z and the detachable portion 39z are detachable relative to each other. After that, the control device 5 reverses the first electric motor 31A to retract the injection piston 37 .

When the first electric motor 31A is reversed, the control device 5 opens the flow control valve 55 and the check valve 59A. As a result, the accumulator 47 is filled with hydraulic fluid discharged from the head-side chamber 35h as the injection piston 37 moves backward. Further, the control device 5 closes the check valve 59B to prohibit the flow of hydraulic fluid from the rod-side chamber 35r to the tank 51, and moves the switching valve 62 to the position allowing the flow of hydraulic fluid from the pump 49 to the rod-side chamber 35r. and drive the pump 49 . As a result, the hydraulic fluid is replenished from the pump 49 to the rod side chamber 35r.

Before, at least part of, and/or after the period during which the injection piston 37 is retracted by the first electric motor 31A as described above, the boosting piston 41 is also retracted. This retraction may be realized by any of the first electric motor 31A, the second electric motor 31B, and the supply of hydraulic fluid. Also, the hydraulic fluid discharged from the rear chamber 35a may or may not fill the accumulator 47 . Specific examples are given below.

In one example (illustrated example), the control device 5 reverses the second electric motor 31B to retract the pressure boosting piston 41 during at least part of the period in which the first electric motor 31A is reversed to retract the injection piston 37. When retracting the booster piston 41, the controller 5 opens the flow control valve 55 and the check valve 59E. As a result, the accumulator 47 is filled with the hydraulic fluid discharged from the rear chamber 35a. The torque or speed of the second electric motor 31B may be set appropriately. For example, the velocity of the intensifier piston 41 is slower than the velocity of the injection piston 37 . As a result, the hydraulic fluid is discharged from the head-side chamber 35h over the period in which the injection piston 37 retreats. However, the pressure-increasing piston 41 is retracted only during a part of the period in which the injection piston 37 is retracted, and the speed of the pressure-increasing piston 41 is equal to or higher than the speed of the injection piston 37, so that the hydraulic fluid is not discharged from the head-side chamber 35h. A period may exist.

In another example, during a part (for example, the initial stage) of the period in which the first electric motor 31A is reversed to retract the injection piston 37, the control device 5 opens the flow control valve 55 and the check valve 59E, and also closes the check valve 59A. is closed (discharge of the hydraulic fluid from the head-side chamber 35h is prohibited). As a result, the pressure-increasing piston 41 retreats as the injection piston 37 retreats, and the accumulator 47 is filled with hydraulic fluid discharged from the rear side chamber 35a. Note that the check valve 59A may self-close. While the pressure-increasing piston 41 is being retracted, the second electric motor 31B may be in a torque-free state, or may be reversed. When reversed, the second electric motor 31B may simply be controlled so that the second drive device 29B does not impede the retraction of the intensifying piston 41, or exert a rearward force on the intensifying piston 41. may be given. In the latter case, the division of roles between the first electric motor 31A and the second electric motor 31B may be appropriately set (either of which may generate a large torque). Contrary to the above, the retraction of the pressure-increasing piston 41 is realized mainly by the reverse rotation of the second electric motor 31B, and the reverse rotation of the first electric motor 31A retracts the injection piston 37 so as not to increase the volume of the head-side chamber 35h. It may be a single one.

Unlike the illustrated example, the detachable portion 33 may be connected to the detachable portion 39z after the detachable portion 33 catches up with the detachable portion 39z and before the need for connection arises. . For example, the detachable portion 33 may be connected to the detachable portion 39z during pressure holding or after pressure holding is completed (but before the need for connection occurs).

The injection piston 37 and the boosting piston 41 are retracted as described above, and then the injection device 9 returns to its initial state by closing various valves. That is, the preparation for the next molding cycle (injection cycle) is completed.

As described above, the injection device 9 according to the embodiment has the injection cylinder 27, the hydraulic device 43, the electric motor 31 (second electric motor 31B), and the control device 5. The injection cylinder 27 is connected to the plunger 21 for pushing out the molding material M into the mold (the mold 101). The injection cylinder 27 also has a piston (pressure boosting piston 41) that can move in a first direction (forward) and in a second direction (backward) opposite thereto. The hydraulic device 43 supplies hydraulic fluid to the injection cylinder 27 . The second electric motor 31B is (indirectly) connected to the pressure boosting piston 41 . The control device 5 simultaneously applies a first force to the front by the hydraulic fluid and a second force to the rear by the second electric motor 31B, which is smaller than the first force, to the intensifying piston 41, and this , the hydraulic device 43 and the second electric motor 31B are controlled so as to move the pressure increasing piston 41 forward.

Therefore, for example, as described with reference to FIG. can be performed by the second electric motor 31B that produces As a result, for example, power consumption can be reduced while increasing control accuracy.

The injection cylinder 27 is arranged such that the plunger 21 advances toward the mold 101 (moves in the direction of pushing out the molding material into the mold 101) by the movement of the pressure-increasing piston 41 in the first direction. ), may be connected to the plunger 21 . In another aspect, the first direction mentioned above may be forward.

In this case, for example, in the operation of pushing out the molding material toward the mold 101, the above-described hybrid drive mode (the force in the first direction by the hydraulic fluid and the force in the second direction by the second electric motor 31B are increased). Aspects applied to the pressure piston 41) are realized. Normally, the operation of pushing out the molding material toward the mold 101 requires a large force. Therefore, by realizing the driving mode described above in such an operation, for example, the effect of reducing power consumption is improved.

Contrary to the above, the direction in which the piston moves so as to retract the plunger 21 is defined as the first direction, and the opposite direction is defined as the second direction. An action of applying a force in a second direction by the electric motor to the piston that is less than one force may be performed. Also in this case, for example, regarding the retraction of the plunger 21, the effect of improving control accuracy while reducing power consumption is expected. Such a retraction operation may or may not be combined with the operations related to pressure increase and pressure retention in the embodiment.

The injection cylinder 27 may be of a pressure increasing type. That is, the injection cylinder 27 may have an injection piston 37 connected to the rear portion of the plunger 21 and a booster piston 41 behind the injection piston 37 capable of pressurizing the hydraulic fluid. Then, the pressure-increasing piston 41 is applied with the above-described first force by the hydraulic fluid in the first direction and the force in the second direction by the second electric motor 31B, which is smaller than the first force. Actions may be taken. From another point of view, the control device 5 controls the first force in the first direction (forward) by the hydraulic fluid and the second direction (backward) by the second electric motor 31B, which is smaller than the first force. The hydraulic device 43 and the second electric motor 31B may be controlled so that the second force is simultaneously applied to the piston (for example, the pressure boosting piston 41), thereby increasing the pressure. Further, the control device 5 may control the second electric motor 31B such that the second force changes with time while the pressure is being increased.

In this case, in the pressure increase that requires a relatively large force, an operation is performed in which the first force by the hydraulic fluid and the second force by the electric motor are applied to the piston. Therefore, for example, the effect of reducing power consumption is improved. Also, as will be described in detail in the description of a modified example (FIG. 12(a)) to be described later, in comparison with a mode in which a second driving device 29B is provided in a single-barrel injection cylinder that does not have a booster piston 41, , it is easy to miniaturize the configuration of the second driving device 29B.

The control device 5 applies a first force in a first direction (forward) by the hydraulic fluid to the piston (for example, the pressure boosting piston 41), while setting the second electric motor 31B to a state in which it does not generate driving force. The hydraulic device 43 and the second electric motor 31B may be controlled so that the pressure is maintained by

In this case, the effect of reducing power consumption is improved. and/or miniaturization of the second electric motor 31B is facilitated. By downsizing the second electric motor 31B, it becomes easier to use a commercially available electric motor as the second electric motor 31B. Under these circumstances, for example, it is easy to set the holding pressure time to be long (for example, 10 seconds or longer).

The hydraulic device 43 may have an accumulator 47 . The control device 5 may control the hydraulic device 43 so as to apply the hydraulic pressure of the accumulator 47 to the rear of the pressure increasing piston 41 to maintain the pressure.

In this case, for example, just by connecting the accumulator 47 to the rear side chamber 35a, the force necessary for maintaining the pressure can be obtained. Therefore, for example, power consumption is reduced compared to a mode in which the pump 49 applies hydraulic pressure to the rear side chamber 35a to hold the pressure (such a mode is also included in the technology according to the present disclosure). Improves effectiveness. Also in the mode in which the hydraulic pressure from the accumulator 47 is applied to the rear chamber 35a, the hydraulic fluid may be replenished from the pump 49 to the rear chamber 35a in response to leakage of the hydraulic fluid, for example.

The control device 5 applies a first force in a first direction (forward) by the hydraulic fluid and a third force in a second direction (rearward) by the second electric motor 31B, which is larger than the first force, to the piston. (For example, the pressure intensifying piston 41) may be simultaneously applied to the hydraulic pressure device 43 and the second electric motor 31B so that the pressure intensifying piston 41 is stopped at the rear drive limit. Further, the control device 5 reduces the third force to make the rearward force by the second electric motor 31B a second force smaller than the first force, thereby increasing the The hydraulic device 43 and the second electric motor 31B may be controlled to initiate forward movement of the pressure piston 41 .

In this case, for example, the start of movement of the pressure-increasing piston 41 is realized by controlling the second electric motor 31B. On the other hand, the control response of the second electric motor 31B is higher than the control response of the hydraulic device 43 . Therefore, the accuracy of control of the pressure increase start timing by the pressure increase piston 41 can be improved. For example, unlike the embodiment, a mode in which the pressure intensifying piston 41 starts advancing by opening the check valve 59E and starting to supply hydraulic fluid from the accumulator 47 to the rear side chamber 35a (this mode is also the technique according to the present disclosure). ). In this aspect, the time from when the control device 5 outputs the control command to the hydraulic device 43 to when the pressure increasing piston 41 starts moving forward is, for example, 20 msec or more. On the other hand, in this embodiment, the time from when the control device 5 outputs the control command to the second electric motor 31B to when the pressure boosting piston 41 starts moving forward can be set to 10 msec or less.

<Modification>
Various modifications will be described below.

(Modified example of protruding motion)
In the embodiment, the projection operation (time points t9 to t10) in which the plunger 21 pushes the molded product away from the fixed mold 103 is performed by the second driving device 29B. The projecting operation may be performed by the first driving device 29A in addition to or instead of the second driving device 29B.

The dashed lines in "first electric motor", "second electric motor", and "attachment/detachment" in FIG. 10 indicate the operation of such a modification. For example, the control device 5 first connects the detachable portion 33 to the detachable portion 39z of the piston rod 39 . Next, the control device 5 rotates the first electric motor 31A forward to move the piston rod 39 forward. As a result, the molded product is pushed by the plunger 21 and released from the mold. At this time, the second electric motor 31B is stopped, for example. The rod side chamber 35r and the head side chamber 35h may be connected to the tank 51, for example. Alternatively, the hydraulic fluid may be supplied from the pump 49 to the head-side chamber 35h. The second electric motor 31B may be rotated forward while the head-side chamber 35h is closed.

Although not particularly shown, in the projecting operation, instead of or in addition to the force of the electric motor, the force of the hydraulic fluid may be used. For example, hydraulic fluid may be supplied from the accumulator 47 or the pump 49 to the head-side chamber 35h, and the pressure in the head-side chamber 35h may contribute to the discharge operation.

If the detachable portion 33 is used only for retracting the plunger 21 as in the embodiment, only rearward relative movement with respect to the detachable portion 39z is prohibited (and allowed) (forward movement is permitted). A configuration in which relative movement is not prohibited) may also be used.

(Modified example related to the start point of pressure increase by the pressure increase piston)
FIG. 11 is a diagram showing a modification relating to the start timing of pressure increase by the pressure increase piston 41, and corresponds to part of FIG.

In FIG. 10, the point of time (time t5) when the pressure increase due to the supply of the hydraulic fluid to the head-side chamber 35h is completed and the point of time (time t5) when the pressure increase by the pressure increase piston 41 is started are the same. On the other hand, in FIG. 11, the pressure increase start time ts by the pressure increase piston 41 is after the pressure increase completion time t5 by supplying the hydraulic fluid to the head side chamber 35h. The time difference between the two may be set appropriately.

The injection device 9 may be configured so that the user can set the time difference between the time t5 and the time ts. In this case, the time difference may be allowed to be zero. In other words, the operating modes of FIGS. 10 and 11 may be selectively realized in the same injection device 9 as each other. For example, the time difference may be settable in the range of 0-100 msec. Of course, the operation mode of FIG. 10 and the operation mode of FIG. 11 may be different operation modes of the injection device 9 .

In the description of the embodiment, the timing of starting the preparation for pressure increase by the pressure boosting piston 41 (the state in which the pressure boosting piston 41 is stopped at the retraction limit by the second electric motor 31B shown in FIG. 3) is time t5 ( The point before the completion of pressure increase by the injection piston 37) is exemplified. In a mode in which it is essential that the time point ts is after the time point t5, the start timing of preparation for pressure increase by the pressure increasing piston 41 can be after the time point t5.

(Modification of injection cylinder)
FIG. 12(a) is a schematic diagram showing a modification of the injection cylinder.

The illustrated injection cylinder 27A is a so-called single-barrel type that does not have a booster piston 41. In a mode having this injection cylinder 27A, for example, injection in a narrow sense (for example, low-speed injection and high-speed injection), pressure increase, and pressure holding are all performed by supplying hydraulic fluid to the rear of the injection piston 37. Also, the electric motor 31 is connected to the injection piston 37 . In this modified example, a rearward force (second force) is applied to the injection piston 37 by the electric motor 31 as indicated by the arrow a4 in the pressure increase. This force is less than the forward force (first force) applied to the injection piston 37 .

In this manner, the force of the hydraulic fluid and the force of the electric motor act on the piston in opposite directions to move the piston in the direction of the force of the hydraulic fluid (first direction). may be applied. Note that the moving distance of the injection piston 37 is longer than the moving distance of the boosting piston 41 . Therefore, the embodiment can shorten the length of the second screw shaft 73B as compared with the modified example of FIG. 12(a).

In place of or in addition to the electric motor 31 shown in the modification of FIG. may be granted to Also, a rearward force that is less than the forward force due to the hydraulic fluid may be applied in addition to or instead of boosting pressure in the narrow definition of injection (eg, low speed injection and high speed injection). In this case, speed control may be performed by an electric drive. These matters also apply to the mode in which the pressure boosting piston 41 is provided.

As shown in FIG. 12(d), the injection cylinder 27D has a first cylinder member 35p that houses the injection piston 37 and a second cylinder member 35q that houses the pressure boosting piston 41, which are separated from each other. The head-side chamber 35h behind the injection piston 37 and the pressurizing chamber 35b in front of the boosting piston 41 may be communicated with each other through 35c. In this case, the position and orientation of the second cylinder member 35q with respect to the first cylinder member 35p are arbitrary. Furthermore, the position and orientation of the electric drive unit that drives the pressure intensifying piston 41 are also arbitrary. For example, the second cylinder member 35q may be arranged in parallel with the first cylinder member 35p (example shown), or may be arranged so as to intersect. As can be understood from the illustrated example, the direction in which the pressure-increasing piston 41 moves during pressure increase (an example of the first direction) is the rearward direction for the plunger 21 and the injection piston 37, contrary to the first embodiment. may be

(Modification of electric driving device)
The mechanism that converts the rotation of the electric motor 31 (the first electric motor 31A and/or the second electric motor 31B) into linear motion is not limited to the screw mechanism. For example, as shown in FIG. 12(b), the conversion mechanism 68C may be a rack and pinion mechanism. Also, although not shown, the conversion mechanism may be a link mechanism. Further, even if the electric driving device (first driving device 29A or second driving device 29B) does not have a transmission mechanism (first transmission mechanism 67A and/or second transmission mechanism 67B) that transmits rotation, or may have other types of transmission mechanisms. Other types of transmission mechanisms may include, for example, gear mechanisms.

The electric motors (first electric motor 31A and/or second electric motor 31B) may be linear motors. In FIG. 12(c), the electric motor 31C that drives the pressure boosting piston 41 is a linear motor. The electric motor 31C is fixed, for example, to the boosting piston 41, is fixed to the mover 31a made up of one of a magnet and a coil, and to a stationary portion (for example, a frame 45) of the injection device 9, and is fixed to the other of the magnet and the coil. It has a stator 31b consisting of.

The present invention is not limited to the above embodiments and modifications, and may be implemented in various aspects.

The molding machine is not limited to a die casting machine. For example, the molding machine may be another metal molding machine, an injection molding machine, or a molding machine that molds a material obtained by mixing wood flour with a thermoplastic resin or the like. . Further, the molding machine is not limited to horizontal clamping and horizontal injection, and may be, for example, vertical clamping and vertical injection, vertical clamping and horizontal injection, or horizontal clamping and vertical injection. The plunger may be in the form of a screw. Die casting machines are not limited to cold chamber machines, and may be hot chamber machines, for example. The hydraulic fluid is not limited to oil, and may be water, for example.

In the embodiment, an injection device is illustrated in which the injection piston (plunger) is retracted and the accumulator is charged by an electric motor. However, retraction of the injection piston (plunger) and/or filling of the accumulator may be effected by a supply of hydraulic fluid from a pump instead of the electric motor. Also, in the embodiment, the advance of the injection piston (injection in a narrow sense from another point of view) was performed only by supplying hydraulic fluid to the rear of the injection piston. However, at least part or all of injection in a narrow sense may be performed by an electric motor.

As described in the embodiment, the hydraulic device (hydraulic circuit) shown in FIG. 9 is merely an example, and may be modified as appropriate.

For example, a meter-out circuit may be provided instead of or in addition to the meter-in circuit. That is, a flow rate control valve may be provided to control the flow rate of the hydraulic fluid discharged from the rod side chamber 35r, and the injection speed and/or the injection pressure may be controlled by the flow rate control valve.

Further, for example, a run-around circuit may be provided to supply the hydraulic fluid discharged from the rod-side chamber 35r to the head-side chamber 35h. A run-around circuit may be combined with a meter-in circuit and/or a meter-out circuit. When the run-around circuit is combined with the meter-out circuit, the position on the rod-side chamber 35r side of the flow control valve of the meter-out circuit may be connected to the head-side chamber 35h. A position on the side of the tank may be connected to the head-side chamber 35h.

In the embodiment, the accumulator that supplies the working fluid to the head-side chamber 35h and the accumulator that supplies the working fluid to the rear-side chamber 35a are the same accumulator. Unlike the embodiment, the accumulator that supplies the working fluid to the head-side chamber 35h and the accumulator that supplies the working fluid to the rear-side chamber 35a may be separate accumulators.

In the description of the embodiment, for convenience, each valve is named by the name of the type of valve (check valve, switching valve) illustrated in the figure. However, each valve may be a valve other than the type used in the designation.

In the embodiment, pilot pressure for various valves was supplied from an accumulator. However, the pilot pressure may be supplied from a pump or from an accumulator separate from the accumulator for driving the plunger.

In the mode in which the rod-side chamber is filled with hydraulic fluid, the rod-side chamber may be replenished with hydraulic fluid when the piston moves back from an accumulator separate from the accumulator for driving the plunger. This replenishment accumulator may be at a lower pressure than the accumulator for driving the plunger.

In the embodiment, while the pressure-increasing piston 41 is provided, the pressure is also increased by supplying hydraulic fluid to the head-side chamber. However, it is not necessary to increase the pressure by supplying hydraulic fluid to the head-side chamber. That is, only speed control may be performed while the hydraulic fluid is being supplied to the head-side chamber.

DESCRIPTION OF SYMBOLS 1... Die casting machine (molding machine), 5... Control device, 9... Injection device, 19... Sleeve, 21... Plunger, 27... Injection cylinder, 31B... Second electric motor (electric motor), 41... Booster piston (piston), 43...Hydraulic device, 101...Mold (mold), 107...Cavity (of the mold).

Claims

an injection cylinder connected to a plunger for pushing molding material into the mold, the injection cylinder having a piston movable in a first direction and in an opposite second direction;
a hydraulic device that supplies hydraulic fluid to the injection cylinder;
an electric motor coupled to the piston;
Simultaneously applying a first force in said first direction by hydraulic fluid and a second force in said second direction by said electric motor, which is less than said first force, to said piston, whereby said piston a control device for controlling the hydraulic device and the electric motor to move in the first direction;
an injection device having a
2. The injection device according to claim 1, wherein the injection cylinder is connected to the plunger such that movement of the piston in the first direction advances the plunger in a direction to push the molding material into the mold.
The injection cylinder is
an injection piston coupled to the rearward portion of the plunger;
3. The injection device according to claim 2, further comprising a booster piston as said piston capable of pressurizing hydraulic fluid behind said injection piston.
The controller simultaneously applies the first force in the first direction by hydraulic fluid and the second force in the second direction by the electric motor, which is less than the first force, to the piston. 4. The injection device according to claim 2 or 3, wherein the hydraulic device and the electric motor are controlled to apply pressure and thereby increase the pressure.
5. The injection apparatus according to claim 4, wherein the control device controls the electric motor such that the second force changes with time while the pressure is being increased.
The control device applies the first force in the first direction by the hydraulic fluid to the piston, while setting the electric motor to a state in which no driving force is generated, thereby performing holding pressure. 6. The injection device according to claim 4 or 5, which controls a hydraulic device and the electric motor.
The hydraulic device has an accumulator,
7. The injection device according to claim 6, wherein the control device controls the hydraulic device to apply the hydraulic pressure of the accumulator to the rear of the piston, thereby performing the holding pressure.
The control device is
simultaneously applying to the piston the first force in the first direction by hydraulic fluid and a third force in the second direction by the electric motor that is greater than the first force, thereby a stop state in which the piston is stopped at the drive limit in the second direction;
By decreasing the third force, the force in the second direction by the electric motor is the second force smaller than the first force, thereby causing the piston to move in the first direction. 8. The injection device according to any one of claims 1 to 7, wherein the hydraulic device and the electric motor are controlled so as to initiate movement of the .
an injection device according to any one of claims 1 to 8;
a mold clamping device that holds the mold;
A molding machine having a