JP2898676B2 - Mold clamping device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for an injection molding machine or a die casting machine. It relates to improvement of the device.

[Conventional technology]

Generally, in a mold clamping device such as an injection molding machine, in order to speed up the operation of the mold clamping device and to reduce the hydraulic drive source required for the mold clamping device, the opening and closing movement of the mold and the mold clamping are performed. Instead of using a single means (hydraulic cylinder), a method is used in which the movement is performed by dividing the boost cylinder means for movement and the clamping cylinder means.

By the way, such a mold clamping device generally includes a tie bar having a threaded portion and half nut means which can be freely engaged with and disengaged from the threaded portion of the tie bar. One end of the tie bar is provided on a fixed die plate. The half nut means is connected to the piston of the mold clamping cylinder, while the half nut means is engaged at its predetermined position with the screw portion of the tie bar passing therethrough on the outer surface of the moving die plate, thereby being connected to the moving die plate. Have been. However, in such a mold clamping device, when the mold is replaced, the effective length of the tie bar must be changed each time by the changed thickness of the mold. A stroke corresponding to the changed thickness was required, and thus the mold clamping cylinder was necessarily lengthened. That is, the miniaturization of the mold clamping device has not been effectively achieved.

In order to solve such a drawback, the present applicant has previously developed a device capable of shortening the piston stroke of a mold clamping cylinder and applied for a patent (Japanese Patent Publication No. 44-16008). ). That is, as shown in FIGS. 3 and 4, the apparatus basically includes a fixed die plate 12 for holding a fixed mold 10, a movable die plate 16 for holding a movable mold 14, and a fixed die plate 16. A mold opening / closing means 24 comprising a boost cylinder 18 supported by the die plate 12 and a piston rod 22 having one end connected to the piston 20 and the other end connected to the movable die plate 16 (in this embodiment, two sets of the opening / closing means). ), And a mold clamping means 30 composed of a tie bar 26 and a half nut means 28 (four sets in this embodiment). The tie bar
26 is a threaded portion near one end connected to a piston 34 of a mold clamping cylinder 32 provided at one end of the fixed die plate 12.
26A is inserted into the insertion hole 16A of the movable die plate 16 and the support shaft 26B from the screw portion 26A is connected to the key 26C and the bush 3.
It is supported by the support plate 36 via 6A. Reference numeral 49 indicates a support frame. On the other hand, the half nut means 28 includes a drive cylinder 38 fixed to the surface of the movable die plate 16 on the side opposite to the fixed die plate 12, and the cylinder 38 slides through the piston rods 40A, 40B and the rods 42A, 42B. It is composed of a pair of half nuts 44A and 44B that are dynamically opened and closed. Therefore, the half nuts 44A and 44B
The tie bar 26 is fixedly connected to the movable die plate 16 when engaged with the sixth screw portion 26A.

However, in the present apparatus, the mold clamping cylinder 32 is provided with a meshing adjusting device 46 and a meshing detecting device 48 attached thereto. The engagement adjusting device 46 is an extension screw portion 26D of the tie bar 26.
A worm wheel 46B having an inner spline hole that fits into a spline shaft provided outside a screw stopper 46A having an internal thread that meshes with the worm wheel 46B;
Worm 46C that fits and rotates this,
The worms 46C of each of the four sets of mesh detection devices 46 are usually configured to be rotated in conjunction with one motor or manually. One-way engagement detection device
Reference numeral 48 denotes a limit switch 48A attached to the half nut means 28, and a dock 48C provided at a predetermined position of the tie bar screw portion 26A via a pin 48B.
It is composed of

Then, in such a configuration, when the molds 10 and 14 are replaced and the mold thickness is changed, in the present apparatus, the half nuts 44A and 44B and the tie bar screw portion 26A respond to this change in the mold thickness. The screw alignment between them is performed. That is, when the molds 10 and 14 are replaced, first, the worm 46C is rotated so that the screw stopper 46A of the meshing adjustment device 46 moves rightward in the drawing with respect to the extension screw portion 26D, and the mold clamping cylinder 32 is rotated. Is supplied to the oil chamber 32A side, and the tie bar 26 moves to the left in the drawing. Next, after the engagement detecting device 48 is set to the state shown in the drawing, the worm 46C is rotated in the reverse direction from the previous time, and the tie bar 26 moves rightward, whereby the dock 48C comes into contact with the limit switch 48A, and at this position the worm The rotation of 46C is stopped. That is, screw alignment is completed.

However, in this case, the amount of the left / right movement of the tie bar 26 required for the screw alignment is determined by the tie bar screw portion 26A.
The maximum stroke of the mold clamping cylinder piston 34 is
The dimension can be set to allow for some margin in the sum of the one pitch screw of 26A and the extension of the effective length of the tie bar 26 generated during mold clamping. That is, the piston stroke corresponding to the mold thickness change thickness required for the mold clamping cylinder in the conventional ordinary mold clamping device of this type is shortened.
Thus, according to the present device, it is possible to reduce the size of the structure of the mold clamping device. Here, the operation of the injection molding machine will be briefly described. First, when the screw alignment is completed, the engagement detection device 48 is removed, and the boost cylinder 18
The pressure oil is supplied to the oil chamber 18A side to open the mold. Next, pressurized oil is supplied to the oil chamber 18B side, and the movable die plate 16 is moved rightward to close the molds 10 and 14, but immediately before the mold closing is completed, the drive cylinder is closed.
38 is actuated, and half nuts 44A and 44B
It is meshed with 6A. Then, pressurized oil is supplied to the oil chamber 32B of the mold clamping cylinder 32, whereby the mold is clamped.

[Problems to be solved by the invention]

As described above, according to the proposed mold clamping device, the structure of the mold clamping device (particularly, the mold clamping cylinder) can be reduced in size. However, it has been found that this mold clamping device still has the following problems.

That is, in the mold clamping device, firstly, at the same time as the engagement adjusting device 46 for adjusting the screw phase is formed in a rotating mechanism including a worm 46C, and thereby, the tie bar 26 is moved in the longitudinal direction. With such a structure, the structure becomes complicated, and in particular, since the screw stopper 46 requires a thrust seating surface, the overall machining accuracy is highly required and the cost is increased. In addition, a detent key 26C for the tie bar 26 is also required. Further, since a relatively large load is applied to the movement of the tie bar 26, the phase between the four tie bar screw portions 26A is shifted, especially when the four sets of meshing adjustment devices 46 are rotated in conjunction with each other. Is often generated. Next, the mold clamping cylinder 32
Is required to have a stroke for moving the tie bar 26, but since this stroke is positively moved even for one pitch of the screw of the threaded portion 26A, it is actually quite considerable. Is formed in the stroke. For this reason, downsizing of the mold clamping cylinder 32 has been substantially hindered.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mold clamping device which can shorten the piston stroke of a mold clamping cylinder to a minimum, and has a simple structure and can be operated accurately.

[Means for solving the problem]

In order to achieve the above object, a mold clamping device according to the present invention has one end coupled to a piston of a mold clamping cylinder provided on a fixed die plate, and a screw portion near the other end inserted into the movable die plate. A tie bar, and half nut means slidably coupled to a surface of the movable die plate opposite to the fixed die plate and removably meshed with the screw portion of the tie bar, wherein the movable die plate is close to the fixed die plate. A moving mold and a fixed mold are closed, and then the half nut means is engaged with the screw portion of the tie bar to exert a mold clamping force. A small-diameter support shaft is extended at the tip of the portion, the support shaft is rotatably supported on a support plate via a bearing, and a rotation means for rotating the tie bar is provided on the support shaft. The rotation means is configured to perform rotation control based on a test value of a test means for detecting and / or calculating a screw pitch phase difference between a half nut and a tie bar screw portion to perform phase matching of the screw pitch. Features.

In this case, the rotating means may be configured such that the sprockets provided on the support shafts of the plurality of tie bars are connected by interlocking means and driven by one drive source, or the support shafts of the plurality of tie bars may be separately driven. It can be configured to be driven by a source.

In addition, the verification means is configured by calculating means for measuring the thickness of the movable mold and the fixed mold and calculating the screw pitch phase difference between the half nut and the tie bar screw portion, or
It can be constituted by a detecting means for directly detecting the screw pitch phase difference between the half nut and the tie bar screw portion.

[Action]

The mold clamping device of the present invention is provided with a screw pitch phase matching device including a sprocket rotating means for rotating the tie bar and a testing means for testing the phase difference of the screw pitch between the half nut and the tie bar screw portion. Therefore,
The mold-clamping cylinder does not require any piston stroke for the mold thickness change thickness conventionally required for this type of mold-clamping cylinder. This is because the screw pitch phasing is performed by rotating the tie bar, that is, without moving the tie bar in the longitudinal direction.
Therefore, the piston stroke is reduced to a minimum length, usually several mm, with some allowance for the extension of the tie bar effective length generated during mold clamping.

On the other hand, since the screw pitch phase matching device is constituted by the sprocket rotating means, the structure is greatly simplified as compared with the proposed mold clamping device, and the operation is performed smoothly and accurately. Activated.

〔Example〕

Next, an embodiment of a mold clamping device according to the present invention will be described in detail with reference to the accompanying drawings. For convenience of description, the same components as those of the conventional structure shown in FIGS. 3 and 4 are denoted by the same reference numerals, and detailed description thereof will be omitted.

1 and 2, the structure of the mold clamping device according to the present invention is basically the same as that of the conventional mold clamping device shown in FIGS. 3 and 4. That is, the mold clamping device is basically a fixed die plate 12 that holds the fixed mold 10,
A movable die plate 16 that holds the movable die 14, a boost cylinder 18 supported by the fixed die plate 12, and a piston rod 20 having one end coupled to the piston 20 and the other end coupled to the movable die plate 16 from a piston rod 22 Mold opening and closing means
24 (in this embodiment, two sets) and a mold clamping means 52 comprising a tie bar 50 and a half nut means 28
(Consisting of four sets in this embodiment). The tie bar 50 has one end connected to the piston 56 of the mold clamping cylinder 54 provided on the fixed die plate 12, and the screw portion 50A near the other end inserted into the insertion hole 16A of the movable die plate 16. . On the other hand, half nut means 28
A drive cylinder 38 fixed to the surface of the movable die plate 16 on the side opposite to the fixed die plate 12;
38, a pair of half nuts 44A and 44B slidably opened and closed via a piston rod 40 and another rod (not shown). Therefore, when the half nuts 44A, 44B are engaged with the screw portion 50A of the tie bar 50, the tie bar 50 is fixedly connected to the movable die plate 16.

However, in the mold clamping device of the present invention, the tie bar 50
A small-diameter support shaft 50B is extended at the tip of the threaded portion 50A of the support plate 36.
A rotating means 60 for rotating the tie bar 50 is provided on the support shaft 50B so as to be rotatable via a bearing 58, and the rotating means 60 is provided with half nuts 44A, 44B, a tie bar screw portion 50A, The rotation is controlled on the basis of a test means (not shown) for testing the thread pitch phase difference between, so that (as will be understood by the operation detailed later)
Phasing of the thread pitch is achieved.

The rotating means 60 includes a sprocket 62 fixed on the support shaft 50B via a key 62A, an interlocking drive chain 66 suspended between the sprocket 62 via a play wheel 64,
A motor 68 drives the drive chain 66. The motor 68 is supported on a support frame 49. The support shaft 50B may be configured to be driven by separate motors. In addition, sprocket 62
Instead, other driving means, for example, a driving means composed of a worm gear or the like can be used. In addition, the verification means is a commonly known calculation means for calculating the screw pitch phase difference between the half nuts 44A, 44B and the screw portion 50A by measuring the mold thickness 1 of the movable mold 14 and the fixed mold 10. (Not shown)
Alternatively, it can be constituted by a generally known verification means (not shown) for directly detecting the screw pitch phase difference between the half nuts 44A, 44B and the screw portion 50A. The piston 56 of the mold clamping cylinder 54 is
The surface on the B side is formed as an abutting surface and regulates the position of the piston 56 on the loose side (this restriction position is shown in the figure).
The stroke .DELTA.L is understood from the description of the operation to be described later, and the minimum length of the tie bar 50, which is generated at the time of mold clamping, with some allowance for the extension of the effective length thereof. Usually, it is set to about several mm.

Then, in such a configuration, when the molds 10 and 14 are replaced and the mold thickness is changed, in the mold clamping device of the present invention, like the proposed mold clamping device, the mold thickness is changed. On the other hand, screw phase matching between the half nuts 44A, 44B and the tie bar screw portion 50A is performed. That is, when the molds 10, 14 are replaced, first, the oil chamber 18B of the boost cylinder 18
The movable die plate 16 approaches the fixed die plate 12 to close the movable mold 14 and the fixed mold 10 with each other. During this mold closing operation, pressure oil is supplied to the oil chamber 54A side of the mold clamping cylinder 54 to block hydraulically,
Therefore, the contact surface 56A of the piston 56 is held at the loosening-side regulating position in contact with the cylinder wall surface. When the closing of the mold is completed, the mold pressure 1 is measured by a separately provided calculating means (not shown), and the half nuts 44A and 44B and the tie bar screw portions corresponding to the mold pressure 1 are thereby measured. The screw pitch phase difference between 50A is calculated. Then, each tie bar 50 is rotated via the motor 68 and the drive chain 66 by the difference in the calculated phase, whereby the screw pitch phase between the half nut and the tie bar screw portion is adjusted. It is apparent that the same operation can be obtained by using the above-described detecting means in place of the calculating means in this phase matching.

However, the phase adjustment in the above operation is performed using a tie bar 50.
, Ie, without moving the tie bar 50 in the longitudinal direction. Therefore, the piston 56 of the mold clamping cylinder 54 does not require any piston stroke for phase matching. In this way,
The piston stroke of the mold clamping cylinder 54 in the present invention can be reduced to a minimum length, usually a few mm, with some allowance for the extension of the effective length of the tie bar 50 generated during mold clamping. it can. On the other hand, the tie bar rotation means 60
Is constructed by a simple structure of the sprocket-chain means, which simplifies the structure and is manufactured at a low cost, and has a relatively small driving load, so that the operation can be performed smoothly and can be operated accurately. You. Therefore, even when the four tie bars 50 are configured to be driven in conjunction with each other, no phase shift occurs between them. As described above, according to the present invention, it is possible to provide a mold clamping device in which the piston stroke of the mold clamping cylinder can be shortened to a minimum, and the structure is simple, reliable, and accurately operated. .

The operation of the entire injection molding machine equipped with the mold clamping device of the present invention will be briefly described. First, pressurized oil is supplied to the oil chamber 18B side of the boost cylinder 18, and the mold is initially driven at a high speed and at the end at a low speed. Close. During the closing of the mold, the oil chamber 54A side of the mold clamping cylinder 54 is hydraulically blocked and the piston 5 is closed.
The contact surface 56A of No. 6 is held at the loosening-side regulating position. Next, the half nuts 44A and 44B are meshed with the tie bar screw 50A in response to the mold closing completion signal. Next, the oil chamber 54B of the mold clamping cylinder 54 is
The pressure oil is supplied to the side, and a predetermined mold clamping force is exerted. After that, when the injection and cooling of the product are completed, the oil chamber 54
The pressure on the B side is released, and the drive cylinder 38 is driven in the reverse direction, so that the half nuts 44A and 44B are released from meshing with the screw portion 50A. Then, the pressure oil is supplied to the oil chamber 18A side of the boost cylinder 18 by the signal of the opening limit of the half nut, and the mold is opened again.

As described above, the present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above embodiments, and many design changes can be made without departing from the spirit thereof.

〔The invention's effect〕

As described above, the mold clamping device according to the present invention includes a tie bar having a screw portion and a half nut in which the screw portion is detachably meshed, and the movable mold and the fixed mold are closed. Later, in the mold clamping device of the type in which the mold clamping force is exerted by the half nut means being meshed with the screw portion, the mold clamping device includes a screw pitch phase difference between the half nut and the tie bar thread portion. And a rotating means for rotating the tie bar based on the test value, the piston stroke for changing the mold thickness conventionally required for the mold clamping cylinder in the mold clamping device is reduced. This is completely unnecessary, so that the mold clamping cylinder can be shortened to a minimum length. That is, the size of the mold clamping device can be significantly reduced.

Further, since the rotating means is formed in a simple structure such as a sprocket-chain means, there is an advantage that the structure of the whole mold clamping device is simplified and the operation thereof is performed smoothly and accurately.

[Brief description of the drawings]

FIG. 1 is a partially sectional plan view showing an embodiment of a mold clamping device according to the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 4 is a sectional view taken along the line IV-IV in FIG. 10: Fixed die 12: Fixed die plate 14: Moving die 16: Moving die plate 18: Boost cylinder 18A, 8B: Oil chamber 20: Piston 22: Piston rod 24: Opening / closing of die Means 28 Half-nut means 36 Support plate 38 Driving cylinder 40 Piston rods 44A, 44B Half nut 49 Support frame 50 Tie bar 50A Screw part 50B Support shaft 52 … Molding means 54… Moulding cylinder 54A, 54B …… Oil chamber 56… Piston 56A …… Contact surface 58 …… Bearing 60… Rotating means 62 …… Sprocket 64 …… Playwheel 66 …… Drive chain 68 …… Motor

Claims (5)

(57) [Claims] 1. A tie bar having one end coupled to a piston of a mold clamping cylinder provided on a fixed die plate and having a screw portion near the other end inserted through the movable die plate, and a side opposite to the fixed die plate of the movable die plate. And a half nut means slidably coupled to the surface of the tie bar and detachably meshed with the screw portion of the tie bar. The movable die plate approaches the fixed die plate, and the movable mold and the fixed mold are closed. Then, in a mold clamping device configured to exert a mold clamping force by the half nut means being engaged with the screw portion of the tie bar, a small-diameter support shaft is extended at a tip end of the screw portion of the tie bar. The support shaft is rotatably supported on a support plate via a bearing, and a rotation means for rotating the tie bar is provided on the support shaft, and the rotation means is provided with a half nut and a tie bar. A mold clamping device characterized in that the screw pitch is phase-matched by controlling the rotation based on a test value of a test means for detecting and / or calculating a screw pitch phase difference between the screw pitch and the screw portion. 2. The mold clamping device according to claim 1, wherein the rotating means is configured to connect sprockets provided on the support shafts of the plurality of tie bars by interlocking means and to be driven by one drive source. 3. The mold clamping device according to claim 1, wherein the rotating means is configured to drive the support shafts of the plurality of tie bars by separate driving sources. 4. The test means according to claim 1, wherein the test means comprises a calculating means for measuring a thickness of the movable die and the fixed die and calculating a screw pitch phase difference between the half nut and the tie bar screw portion. Mold clamping device. 5. The mold clamping device according to claim 1, wherein the verification means comprises detection means for directly detecting a screw pitch phase difference between the half nut and the tie bar screw portion.