JP3923707B2 - Die casting equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a die casting apparatus for obtaining a die cast product by injecting molten metal into a cavity defined by a pair of die casting molds.
[0002]
[Prior art]
A die casting apparatus 10 as shown in FIG. 3 is known as an apparatus for obtaining a die casting product by injecting molten metal into a cavity defined by a pair of die casting molds. The die casting apparatus 10 includes a sleeve 18 for injecting a molten metal 16 into a cavity 14 defined by a pair of die casting molds 12, 12. The sleeve 18 is driven by an injection hydraulic cylinder 22. A plunger 20 is slidably provided.
[0003]
The injection hydraulic cylinder 22 has a piston 26 connected to the plunger 20 via a piston rod 24. The hydraulic oil is injected into the injection hydraulic cylinder 22 on the cylinder head side of the piston 26, that is, on the opposite side of the piston rod 24. 4 is supplied from the hydraulic oil supply line 40 of the hydraulic circuit 28 shown in FIG. 4, the plunger 20 moves forward, whereby the molten metal 16 is injected from the sleeve 18.
[0004]
The hydraulic circuit 28 has a hydraulic pump 30, and the pressure oil discharged from the hydraulic pump 30 is supplied to the accumulator 38 as an operating oil for operating the injection hydraulic cylinder 22, the electromagnetic valve 32, the operating oil supply line 34, and the reverse. It is supplied via a stop valve 36.
[0005]
The accumulator 38 communicates with the head side of the injection hydraulic cylinder 22, that is, the side opposite to the piston rod 24 via the hydraulic oil supply pipe 40. The hydraulic oil supply line 40 is provided with a logic valve 42 that is opened and closed by an electromagnetic pilot valve 44. When the electromagnetic pilot valve 44 is switched to the left position, it communicates with the pilot chamber of the logic valve 42. The A port of the electromagnetic pilot valve 44 communicates with the tank 46, and as a result, the valve body of the logic valve 42 is moved in the opening direction by the pressure of the hydraulic oil stored in the accumulator 38, and is stored in the accumulator 38. The hydraulic oil flows into the head side of the injection hydraulic cylinder 22 through the hydraulic oil supply conduit 40.
[0006]
The hydraulic circuit 28 has a flow rate control unit 48 that controls the flow rate of the hydraulic oil discharged from the injection hydraulic cylinder 22 to the tank 46 when the molten metal is injected. The flow rate control unit 48 has a flow rate control valve 50. When the flow rate control valve 50 is switched from the illustrated position to the right position in the drawing, the hydraulic oil is injected as the plunger 20 moves forward. 22 flows out from the piston rod side, and is discharged to the tank 46 through the flow control valve 50 and the hydraulic oil discharge pipe 52. Further, the flow rate control unit 48 has a pilot servo valve 54 for operating the flow rate control valve 50, and pressure oil from the hydraulic pump 30 is supplied to the pilot servo valve 54 from a pilot pressure supply line 56 as a pilot pressure. Has been.
[0007]
The pilot pressure supply line 56 is branched from a hydraulic oil supply line 34 between the electromagnetic valve 32 and the check valve 36, and the above-described electromagnetic pilot valve 44 is branched to the pilot pressure supply line 56. 58, and a hydraulic oil supply pipe 60 that supplies hydraulic oil to the piston rod side of the injection hydraulic cylinder 22 is connected via a logic valve 62, an electromagnetic switching valve 64, and a branch pipe 66. ing.
[0008]
The electromagnetic pilot valve 44 is configured to operate in response to a control signal from a control device (not shown). When the electromagnetic pilot valve 44 is switched to the illustrated position by a signal from the control device, the accumulator 38 supplies an injection hydraulic cylinder. At the same time as the supply of pressure oil to 22 is shut off, the B port of the electromagnetic pilot valve 44 communicating with the pilot chamber of the logic valve 62 communicates with the tank 46. At this time, when the electromagnetic switching valve 64 is switched to the illustrated position by a signal from the control device, the A port of the electromagnetic switching valve 64 communicates with the tank 46 and at the same time the B port of the electromagnetic switching valve 64 is connected to the branch line 66. Communicate. As a result, the pressure oil from the hydraulic pump 30 passes through the electromagnetic valve 32, the hydraulic oil supply pipe 34, the pilot pressure supply pipe 56, the branch pipe 66, the electromagnetic switching valve 64, the logic valve 62, and the hydraulic oil supply pipe 60. Then, it is supplied to the piston rod side of the injection hydraulic cylinder 22 and the plunger 20 moves backward, and the hydraulic oil on the head side of the injection hydraulic cylinder 22 passes through the hydraulic oil discharge pipe 68 and the electromagnetic switching valve 64 to the tank 46. Discharged.
[0009]
[Problems to be solved by the invention]
In such a die casting apparatus, the hydraulic oil is supplied to the piston rod side of the injection hydraulic cylinder 22 and the hydraulic oil supplied to the head side of the injection hydraulic cylinder 22 is supplied to the hydraulic oil discharge pipe 68 and the electromagnetic switching valve 64. Then, by discharging to the tank 46, the plunger 20 that has advanced to a predetermined position can be retracted to the original position. However, when the plunger 20 is moved backward, the electromagnetic pilot valve 44, the flow rate control valve 50, and the electromagnetic switching valve 64 described above must be switched by a control device (not shown), which complicates the configuration of the control device.
[0010]
Therefore, in order to solve such a problem, the flow control valve 50 described above is constituted by a three-position switching valve 70 as shown in FIG. 5, and this three-position switching valve 70 is controlled by a pilot servo valve 54. A device in which the plunger 20 is retracted has been proposed. According to such a die-casting device, the logic valve 62 and the electromagnetic switching valve 64 are not required unlike the die-casting device shown in FIG. 4, so that the control device for controlling the valves of the hydraulic circuit 28 has a simple configuration. Is possible.
[0011]
However, in the conventional die casting apparatus shown in FIG. 5, the hydraulic oil from the accumulator 38 is prevented from flowing to the three-position switching valve 70 except during the plunger injection operation, and the piston rod 24 of the injection hydraulic cylinder is used. There not must provide a pilot type check valve 72 for introducing hydraulic oil from the head side oil chamber during retraction to the tank to the hydraulic fluid discharge line 68, increase the cost of the hydraulic circuit for driving the injection hydraulic cylinder There was a problem of letting. 4 and 5, the flow rate of the flow rate control valves 50 and 70 is not controlled during the backward movement.
[0012]
The present invention has been made to solve the above-described problems, and its object is to control the valves of a hydraulic circuit that drives an injection hydraulic cylinder with a control device having a relatively simple configuration without causing an increase in cost. Another object of the present invention is to provide a die casting apparatus that can control the forward and backward speeds of the plunger with a simple configuration.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, a die casting apparatus according to the present invention comprises a sleeve for injecting molten metal into a cavity defined by a pair of die casting molds, and a plunger slidably provided in the sleeve. An injection fluid pressure cylinder having a piston coupled to the plunger via a piston rod, an accumulator for accumulating a working fluid for operating the injection fluid pressure cylinder when the molten metal is injected by the advance of the plunger, and the accumulator A hydraulic oil supply line (34) for connecting pressure oil from a fluid pressure pump to a first hydraulic oil supply pipe line portion communicated with a pressure oil supply / discharge port of the hydraulic oil via a check valve (36); An oil chamber on the head side of the injection hydraulic cylinder connected to the pipe (58) branched from the oil supply pipe (34) via an electromagnetic pilot valve (44). A second hydraulic fluid supply line portion and the first hydraulic fluid supply line portion communicating, interrupted by the operation of the solenoid pilot valve (44), the logic valve communicating with (42), the injection of the molten metal A flow rate control unit that controls the flow rate of the working fluid that is sometimes discharged from the injection fluid pressure cylinder to the tank, and the flow rate control unit communicates with an oil chamber on the piston rod side of the injection fluid pressure cylinder. Communicating with a first oil passage port (A), a second oil passage port (B) communicating with the second hydraulic oil supply pipeline portion, and a pipeline (58) branched from the hydraulic oil supply pipeline (34) And a fourth oil passage port (T) communicating with the tank, and the first oil passage port (A) and the fourth oil passage port (T) when the plunger moves forward. ) Only when the plunger is retracted, the first oil passage port ( ) And the third oil supply port (P), and three positions as a flow control valve having a spool (741) for communicating the second oil supply port (B) and the fourth oil supply port (T). The three-position using a switching valve, a position detector (742) for detecting a spool position of the three-position switching valve, and pressure oil from a pipe (56) branched from the hydraulic oil supply pipe (34) A servo valve that generates a pilot pressure for operating the spool position of the switching valve, and a control device that provides a command signal to the servo valve and inputs a detection signal from the position detector (742) as a feedback signal. The injection speed of the plunger is variable.
In addition, a die casting apparatus according to the present invention for solving the above-mentioned problems is provided with a sleeve for injecting molten metal into a cavity defined by a pair of die casting molds, and slidably provided in the sleeve. A plunger, an injection fluid pressure cylinder having a piston connected to the plunger via a piston rod, and an accumulator for accumulating a working fluid that operates the injection fluid pressure cylinder during a molten metal injection operation by the advance of the plunger; A hydraulic oil supply line (34) for connecting the pressure oil from the fluid pressure pump to the first hydraulic oil supply line portion communicating with the pressure oil supply / discharge port of the accumulator via a check valve (36); A head side of the injection hydraulic cylinder connected to a pipe (56) branched from the hydraulic oil supply pipe (34) via an electromagnetic pilot valve (44). A logic valve (42) that shuts off and communicates the second hydraulic oil supply pipe line portion communicating with the oil chamber and the first hydraulic oil supply pipe line portion by operating the electromagnetic pilot valve (44); A flow rate control unit that controls the flow rate of the working fluid discharged from the injection fluid pressure cylinder to the tank when the molten metal is injected, and the flow rate control unit is an oil chamber on the piston rod side of the injection fluid pressure cylinder. A first oil passage port (A) communicating with the second fluid passage port (B) communicating with the oil chamber on the head side of the injection fluid pressure cylinder, and a pipe branched from the first hydraulic oil supply conduit portion A third oil passage port (P) communicating with the passage (82) and a fourth oil passage port (T) communicating with the tank; and when the plunger is advanced, the first oil passage port (A) and the first oil passage port (T) When only 4 oil ports (T) are in communication, the plunger is retracted Is a spool (741) which communicates the first oil passage port (A) and the third oil passage port (P) and further communicates the second oil passage port (B) and the fourth oil passage port (T). A three-position switching valve as a flow rate control valve, a position detector (742) for detecting the spool position of the three-position switching valve, and a pipe branch (82) branched from the first hydraulic oil supply pipe section A servo valve for generating a pilot pressure for manipulating the spool position of the three-position switching valve using pressure oil from the engine, a command signal to the servo valve, and a detection signal from the position detector (742) are fed back And a control device for inputting as a signal, wherein the injection speed of the plunger is variable.
[0014]
In this case, the single three-position switching valve is preferably a closed center type three-position switching valve.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. Note that the same or corresponding parts as those shown in FIGS. 3 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted for the sake of convenience.
[0016]
FIG. 1 is a diagram showing a schematic configuration of a hydraulic circuit that drives an injection hydraulic cylinder of a die casting apparatus according to a first embodiment of the present invention. In the figure, a die casting apparatus according to an embodiment of the present invention is a closed center type three-position switching as a flow rate control valve for controlling the flow rate of hydraulic oil discharged from the injection hydraulic cylinder 22 to the tank 46 when molten metal is injected. A valve 74 is provided.
[0017]
The three-position switching valve 74 has four oil passage ports A, B, T, and P. The first oil passage port A is on the piston rod 24 side of the injection hydraulic cylinder 22, and the second oil passage port B is The third oil passage port P is connected to the pilot hydraulic pressure supply line 56, the hydraulic oil supply line 34, and the solenoid valve on the side opposite to the piston rod 24 of the injection hydraulic cylinder 22 through the hydraulic oil discharge pipe 68, that is, on the cylinder head side. The hydraulic oil pump 30 is connected to the discharge port of the hydraulic pump 30 through the fourth oil supply port T.
[0018]
The three-position switching valve 74 has a spool 741 that selectively communicates the first to fourth oil passages A, B, P, and T. The spool 741 is driven by the pilot pressure from the pilot servo valve 54. It is configured to slide. Further, the three-position switching valve 74 has a position detector 742 for detecting the position of the spool 741, and the signal output from the position detector 742 is subjected to signal processing by a control device (not shown) and then switched to the three-position switching. The signal is fed back to the pilot servo valve 54 as a signal indicating the opening degree of the valve 74 (the amount of movement of the spool 741). The opening of the three-position switching valve 74 includes a pressure detector 76 for detecting the pressure on the cylinder head side of the injection hydraulic cylinder 22, a pressure detector 78 for detecting the pressure on the piston rod side of the injection hydraulic cylinder 22, and a plunger. It is controlled based on a signal from a position detector 80 that detects 20 positions.
[0019]
In such a configuration, when the pilot servo valve 54 is switched from the position shown in FIG. 1 (neutral position) to the right position in the drawing by a signal from a control device (not shown), the pilot servo pressure from the pilot servo valve 54 causes three positions. The spool 741 of the switching valve 74 slides to the right in the figure, and only the first oil passage A and the fourth oil passage T communicate with each other.
[0020]
At this time, when the plunger 20 moves forward by the hydraulic oil supplied from the accumulator 38 to the cylinder head side of the injection hydraulic cylinder 22, the hydraulic oil moves from the piston rod side of the injection hydraulic cylinder 22 as the plunger 20 moves forward. The hydraulic oil discharged and discharged from the piston rod side of the injection hydraulic cylinder 22 is discharged to the tank 46 through the first oil passage A and the fourth oil passage T of the three-position switching valve 74.
[0021]
On the other hand, when the pilot servo valve 54 is switched from the position shown in FIG. 1 to the left position in the figure by a signal from the control device, the spool 741 of the three-position switching valve 74 is left in the figure by the pilot pressure from the pilot servo valve 54. The first oil passage A and the third oil passage P communicate with each other, and the second oil passage B and the fourth oil passage T communicate with each other.
[0022]
At this time, the pressure oil discharged from the hydraulic pump 30 flows into the third oil passage P of the three-position switching valve 74 through the solenoid valve 32, the hydraulic oil supply pipe 34, and the pilot pressure supply pipe 56, and the plunger 20 Is supplied from the first oil passage A to the piston rod side of the injection hydraulic cylinder 22 as hydraulic oil for reversing the engine. Also, this time from the cylinder head side of the injection hydraulic cylinder 22 is actuated oil discharged along with the retracting movement of the plunger 20, the hydraulic oil discharged from the cylinder head side of the injection hydraulic cylinder 22 is 3-position switching valve 74 The oil is discharged to the tank 46 through the second oil passage B and the fourth oil passage T. In FIGS. 1 and 2, a portion of the hydraulic oil supply pipe 40 between the upper end port of the logic valve 42 and the pressure oil supply / discharge port of the accumulator 38 is the first hydraulic oil supply in the present invention. A pipe line part corresponding to the pipe line part and between the logic valve 42 and the oil chamber on the head side of the injection hydraulic cylinder 22 corresponds to the second hydraulic oil supply pipe line part in the present invention.
[0023]
As described above, in the die casting apparatus according to the first embodiment of the present invention, when the plunger 20 is moved forward, only the first oil passage A and the fourth oil passage T of the three-position switching valve 74 communicate with each other, and the reverse When the plunger 20 is moved backward, the first oil passage port A, the third oil passage port P, the second oil passage port B, and the fourth oil passage port T of the three-position switching valve 74 communicate with each other. Therefore, it is not necessary to provide the pilot type check valve 72 in the hydraulic oil discharge pipe 68 as in the conventional example shown in FIG. 5, so that the cost of the valves of the hydraulic circuit that drives the injection hydraulic cylinder 22 increases. And can be controlled by a control device having a relatively simple configuration.
[0024]
In the above-described embodiment, the forward and backward speeds of the plunger 20 can be controlled with a simple configuration by controlling the movement amount of the spool 741 of the three-position switching valve 74 with the pilot pressure from the pilot servo valve 54. .
[0025]
In the first embodiment described above, the pressure oil from the hydraulic pump 30 is supplied to the third oil passage port P of the three-position switching valve 74. However, as in the second embodiment shown in FIG. The pressure oil from the accumulator 38 may be supplied to the third oil passage port P of the three-position switching valve 74 via the branch line 82 branched from the hydraulic oil supply line 40. With such a configuration, when the plunger 20 is moved backward, the pressure oil from the accumulator 38 flows into the piston rod side of the injection hydraulic cylinder 22, so that the plunger 20 can be moved back to the original position in a shorter time than the first embodiment described above. Can be retracted to position.
[0026]
【The invention's effect】
As described above, the die casting apparatus according to the present invention includes a sleeve for injecting molten metal into a cavity defined by a pair of die casting molds, a plunger slidably provided in the sleeve, An injection fluid pressure cylinder having a piston connected to a plunger via a piston rod; an accumulator for accumulating a working fluid for operating the injection fluid pressure cylinder during a molten metal injection operation by the advance of the plunger; and a pressure of the accumulator A hydraulic oil supply line (34) for connecting pressure oil from a fluid pressure pump to a first hydraulic oil supply line portion communicating with the oil supply / discharge port via a check valve (36); An electromagnetic pilot valve (44) is connected to a pipe (58) branched from the pipe (34) and communicates with the oil chamber on the head side of the injection hydraulic cylinder. A second hydraulic fluid supply line portion and the first hydraulic fluid supply line portion that, the blocking by the operation of the solenoid pilot valve (44), the logic valve communicating with (42), at the time of injection of the molten metal A flow rate control unit that controls the flow rate of the working fluid discharged from the injection fluid pressure cylinder to the tank, and the flow rate control unit communicates with an oil chamber on the piston rod side of the injection fluid pressure cylinder. 1 oil passage port (A), a second oil passage port (B) communicating with the second hydraulic oil supply pipeline portion, and a pipeline (58) branched from the hydraulic oil supply pipeline (34). The oil passage has a third oil passage port (P) and a fourth oil passage port (T) communicating with the tank, and the first oil passage port (A) and the fourth oil passage port (T) when the plunger moves forward. Only when the plunger is retracted, the first oil passage port (A) and A three-position switching valve as a flow rate control valve having a spool (741) that communicates the third fluid port (P) and further communicates the second fluid port (B) and the fourth fluid port (T). And a position detector (742) for detecting the spool position of the 3-position switching valve, and the 3-position switching valve using pressure oil from a pipe (56) branched from the hydraulic oil supply pipe (34). A servo valve that generates a pilot pressure for manipulating the spool position, and a control device that provides a command signal to the servo valve and inputs a detection signal from the position detector (742) as a feedback signal, Since the injection speed of the plunger is variable, the valves of the hydraulic circuit that drives the injection hydraulic cylinder can be controlled with a relatively simple control device without causing an increase in cost, and the plunger moves forward. In addition, it is possible to provide a die casting apparatus that can control the reverse speed with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a hydraulic circuit that drives an injection hydraulic cylinder of a die casting apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a schematic configuration of a hydraulic circuit that drives an injection hydraulic cylinder of a die casting apparatus according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a configuration of a molten metal injection portion of a die casting apparatus.
FIG. 4 is a diagram showing a schematic configuration of a hydraulic circuit for driving an injection hydraulic cylinder of a conventional die casting apparatus.
FIG. 5 is a diagram showing a schematic configuration of another hydraulic circuit for driving an injection hydraulic cylinder of a conventional die casting apparatus.
[Explanation of symbols]
12 Die-casting mold 14 Cavity 16 Molten metal 18 Sleeve 20 Plunger 22 Molten oil injection hydraulic cylinder 24 Piston rod 26 Piston 30 Hydraulic pump 38 Accumulator 46 Tank 54 Pilot servo valve 74 Three-position switching valve A First oil passage B Second oil passage Port T 4th fluid port P 3rd fluid port 741 Spool

Claims (2)

A sleeve for injecting molten metal into a cavity defined by a pair of die casting molds, a plunger slidably provided in the sleeve, and a piston connected to the plunger via a piston rod An injection fluid pressure cylinder, an accumulator for accumulating a working fluid for operating the injection fluid pressure cylinder during a molten metal injection operation by advancement of the plunger, and a first hydraulic oil supply in communication with the pressure oil supply / discharge port of the accumulator A hydraulic oil supply line (34) for connecting pressure oil from the fluid pressure pump to the pipe line part via a check valve (36);
Second hydraulic oil supply connected to a pipe (58) branched from the hydraulic oil supply pipe (34) via an electromagnetic pilot valve (44) and communicating with the oil chamber on the head side of the injection hydraulic cylinder. A logic valve (42) that shuts off and communicates a pipe line part and the first hydraulic oil supply pipe line part by operating the electromagnetic pilot valve (44);
A flow rate control unit for controlling the flow rate of the working fluid discharged from the injection fluid pressure cylinder to the tank at the time of injection of the molten metal,
The flow rate controller
A first oil passage port (A) communicating with the oil chamber on the piston rod side of the fluid pressure cylinder for injection, a second oil passage port (B) communicating with the second hydraulic oil supply pipe portion, and the hydraulic oil It has a third oil passage port (P) that communicates with the pipeline (58) branched from the supply conduit (34) and a fourth oil passage port (T) that communicates with the tank. Only one oil passage port (A) and the fourth oil passage port (T) are communicated, and when the plunger is retracted, the first oil passage port (A) and the third oil passage port (P) are further communicated. A three-position switching valve as a flow control valve having a spool (741) for communicating the second oil passage port (B) and the fourth oil passage port (T);
A position detector (742) for detecting the spool position of the three-position switching valve;
A servo valve that generates a pilot pressure for operating the spool position of the three-position switching valve using pressure oil from a pipe (56) branched from the hydraulic oil supply pipe (34);
A control device for providing a command signal to the servo valve and inputting a detection signal from the position detector (742) as a feedback signal;
A die casting apparatus characterized in that an injection speed of the plunger is variable. A sleeve for injecting molten metal into a cavity defined by a pair of die casting molds, a plunger slidably provided in the sleeve, and a piston connected to the plunger via a piston rod An injection fluid pressure cylinder, an accumulator for accumulating a working fluid for operating the injection fluid pressure cylinder during a molten metal injection operation by advancement of the plunger, and a first hydraulic oil supply in communication with the pressure oil supply / discharge port of the accumulator A hydraulic oil supply line (34) for connecting pressure oil from the fluid pressure pump to the pipe line part via a check valve (36);
Second hydraulic oil supply connected to a pipe (56) branched from the hydraulic oil supply pipe (34) via an electromagnetic pilot valve (44) and communicating with the oil chamber on the head side of the injection hydraulic cylinder. A logic valve (42) that shuts off and communicates a pipe line part and the first hydraulic oil supply pipe line part by operating the electromagnetic pilot valve (44);
A flow rate control unit for controlling the flow rate of the working fluid discharged from the injection fluid pressure cylinder to the tank at the time of injection of the molten metal,
The flow rate controller
A first oil communication port (A) communicating with an oil chamber on the piston rod side of the injection fluid pressure cylinder, a second oil communication port (B) communicating with an oil chamber on the head side of the injection fluid pressure cylinder, The plunger has a third oil passage port (P) communicating with the pipe line (82) branched from the first hydraulic oil supply pipe portion and a fourth oil passage port (T) communicated with the tank, and the forward movement of the plunger. Sometimes only the first oil supply port (A) communicates with the fourth oil supply port (T),
When the plunger is retracted, the first oil supply port (A) and the third oil supply port (P) are connected, and the second oil supply port (B) and the fourth oil supply port (T) are connected. A three-position switching valve as a flow control valve having a spool (741);
A position detector (742) for detecting the spool position of the three-position switching valve;
A servo valve that generates a pilot pressure for operating a spool position of the three-position switching valve using pressure oil from a pipe (82) branched from the first hydraulic oil supply pipe section;
A control device for providing a command signal to the servo valve and inputting a detection signal from the position detector (742) as a feedback signal;
A die casting apparatus characterized in that an injection speed of the plunger is variable.

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