JP2020124734A - Injection device and die cast machine - Google Patents

Abstract

To provide an injection device which causes a piston to move forward stably in meter-out control, and to provide a die cast machine.SOLUTION: This injection device 7 includes: a compression part 76 which compresses a rod side chamber S1 before injection of molten metal by a plunger 6 starts; and a switch part 79 which switches connection between the rod side chamber S1 and the compression part 76 and interception of the connection. The switch part 79 is disposed between the rod side chamber S1 and the compression part 76.SELECTED DRAWING: Figure 2

Description

The present invention relates to an injection device and a die casting machine, and more particularly to an injection device and a die casting machine including a piston connected to a plunger and a cylinder containing the piston.

BACKGROUND ART Conventionally, an injection device and a die casting machine including a piston connected to a plunger and a cylinder containing the piston are known (see, for example, Patent Document 1).

The above-mentioned Patent Document 1 discloses an injection device for a high-pressure casting machine (for a die casting machine), which includes a piston connected to a plunger and an injection cylinder containing the piston. The injection device of Patent Document 1 includes an accumulator and a meter-out logic valve.

The internal space (cylinder chamber) of the injection cylinder of Patent Document 1 is divided into a head side pressure chamber (head side chamber) and a rod side pressure chamber (rod side chamber) by the head portion of the piston. The area of the end surface on the rod side pressure chamber side of the head portion of the piston of Patent Document 1 is the same as the end surface on the head side pressure chamber side of the piston head portion by the amount of the rod portion of the piston arranged in the rod side pressure chamber. Smaller than the area.

The accumulator of Patent Document 1 is configured to supply hydraulic oil to each of the head-side pressure chamber and the rod-side pressure chamber. The meter-out logic valve of Patent Document 1 is configured to discharge the hydraulic oil in the rod-side pressure chamber supplied by the accumulator.

Here, in the head portion of the piston of Patent Document 1, a forward force for advancing the piston is generated by applying the pressure of the hydraulic oil in the head side pressure chamber to the end surface of the head portion of the piston on the head side pressure chamber side. Occurs. In the head portion of the piston of Patent Document 1 described above, the pressure of the hydraulic oil in the rod-side pressure chamber is applied to the end surface of the piston head portion on the rod-side pressure chamber side, so that a retreating force for retracting the piston is generated.

The injection device of Patent Document 1 is configured to perform meter-out control in which the forward force generated in the hydraulic oil in the head side pressure chamber is controlled by the backward force generated in the hydraulic oil in the rod side pressure chamber. There is.

However, in the injection device of Patent Document 1, when the injection of the molten metal by the plunger is started by supplying the hydraulic oil from the same accumulator, the pressure of the hydraulic oil in the rod side pressure chamber and the head side pressure chamber It is about the same as the hydraulic oil pressure. Further, since the area of the end surface of the piston head portion on the rod side pressure chamber side is smaller than the area of the end surface of the piston head portion on the head side pressure chamber side, the retreating force is smaller than the advancing force. Therefore, in the injection device of Patent Document 1 described above, when the injection of the molten metal by the plunger is started, the forward force generated at the end surface on the head side pressure chamber side in the head portion of the piston is applied to the rod side pressure chamber side in the head portion of the piston. It is difficult to perform meter-out control that is suppressed by the backward force generated on the end face. Therefore, the injection device of Patent Document 1 has a disadvantage that the piston advances in an uncontrollable state up to a position where the forward force and the backward force generated in the head portion of the piston are balanced.

JP, 6-339764, A

Therefore, it is conceivable that the injection device may be provided with a pressurizing unit for pressurizing the rod-side pressure chamber in order to eliminate the above-mentioned inconvenience, although not disclosed in Patent Document 1 described above. Since the pressurizing unit cannot pressurize the rod side pressure chamber when it is arranged between the meter-out logic valve and the tank, it is considered that it is arranged between the rod-side pressure chamber and the meter-out logic valve. To be

In such an injection device, the forward force and the backward force due to the area of the end surface of the piston head portion on the rod side pressure chamber side being smaller than the area of the head side pressure chamber side end surface of the piston head portion The difference can be compensated by pressurizing the rod side pressure chamber with the pressurizing unit.

However, in the above-mentioned injection device, even when the pressure in the rod side pressure chamber is reduced by discharging the hydraulic oil in the rod side pressure chamber through the meter out logic valve by the meter-out control, the rod side pressure chamber will be There is the inconvenience of being pressurized. That is, in the above-mentioned injection device, when the pressurizing unit is arranged between the rod side pressure chamber and the meter-out logic valve, the pressure change in the rod-side pressure chamber becomes unstable when performing the meter-out control. .. Therefore, the injection device has a problem that it is difficult to stably move the piston forward in the meter-out control.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an injection device and a die casting machine capable of stably advancing a piston in meter-out control. It is to be.

In order to achieve the above-mentioned object, an injection device according to a first aspect of the present invention includes a piston connected to a plunger, a cylinder including a piston, and a cylinder chamber that is divided into a rod side chamber and a head side chamber by the piston. Before the injection of the molten metal by the plunger is started, the rod side chamber is provided with a pressurizing unit for pressurizing the rod side chamber and a switching unit for switching connection or disconnection between the rod side chamber and the pressurizing unit. And the pressure part.

As described above, the injection device according to the first aspect of the present invention is provided with the switching unit that switches connection or disconnection between the rod side chamber and the pressurizing unit. Then, the switching unit is arranged between the rod side chamber and the pressurizing unit. As a result, when performing meter-out control, when the hydraulic oil in the rod-side chamber is discharged to reduce the pressure in the rod-side chamber, the connection between the rod-side chamber and the pressurizing unit is cut off by the switching unit. The pressure portion can prevent the rod side chamber from being pressurized. Therefore, when performing the meter-out control, when the pressure of the rod side chamber is reduced by discharging the hydraulic oil supplied to the rod side chamber, it is possible to avoid pressurizing the rod side chamber by the pressurizing unit. .. As a result, when performing the meter-out control, it is possible to prevent the pressure change in the rod-side chamber from becoming unstable, so that the piston can be stably advanced in the meter-out control. In addition, since the piston can be stably advanced in the meter-out control, the plunger can be stably advanced, so that the injection of the molten metal can be stabilized. Even when the pressure of the hydraulic oil in the rod-side chamber becomes higher than that in the pressurizing unit, the switching unit cuts off the connection between the rod-side chamber and the pressurizing unit, so Backflow can be prevented.

The injection device according to the first aspect preferably further includes a control unit that controls the disconnection of the rod side chamber and the pressurizing unit by the switching unit when the injection of the molten metal by the plunger is started. According to this structure, when the molten metal is injected by the plunger by the meter-out control, it is possible to avoid pressurizing the rod side chamber by the pressurizing unit from the start of the injection of the molten metal by the plunger. Accordingly, it is possible to prevent the pressure of the hydraulic oil in the rod-side chamber from becoming unstable due to the pressurizing portion while the molten metal is being injected by the plunger. As a result, while the molten metal is being injected by the plunger, the injection of the molten metal can be stabilized by stably advancing the piston.

In this case, preferably, a tank for discharging hydraulic oil in the rod-side chamber is further provided, the switching unit is configured to switch connection or disconnection between the rod-side chamber and the tank, and the control unit is configured to inject molten metal by the plunger. When the start is started, the switching unit cuts off the connection between the rod side chamber and the pressurizing unit, and the switching unit controls the connection between the rod side chamber and the tank. According to this structure, while the meter-out control for advancing the piston by adjusting the pressure in the rod side chamber by discharging the hydraulic oil in the rod side chamber to the tank is being performed, By disconnecting the connection by the switching portion, it is possible to prevent the rod side chamber from being pressurized by the pressurizing portion. As a result, it is possible to prevent the pressure of the hydraulic oil in the rod-side chamber from becoming unstable due to the pressurizing unit during the meter-out control. Also, unlike meter-in control in which the piston is advanced by controlling only the forward force of the hydraulic oil in the head side chamber, in meter-out control, the forward force generated in the hydraulic oil in the head side chamber is applied to the hydraulic oil in the rod side. It can be suppressed by the receding force generated in the. Therefore, unless the forward force is precisely controlled, unlike the meter-in control in which the piston advances (jumps out) in an uncontrollable state, the meter-out control does not require precise control of the forward force. As a result, it is not necessary to provide a plurality of valves necessary for finely adjusting the advancing force on the upstream side of the head side chamber of the cylinder, so that it is possible to suppress an increase in the number of parts of the injection device.

In the injection device including the control unit, preferably, the control unit is configured to perform control for connecting the rod side chamber and the pressurizing unit by the switching unit at a predetermined timing before the injection of the molten metal by the plunger is started. Has been done. According to this structure, the pressure of the hydraulic oil in the rod side chamber can be increased by the pressurizing unit at a predetermined timing. Here, in the direction orthogonal to the extending direction of the piston, the area of the end surface of the piston head portion on the rod side chamber side is smaller than the area of the end surface of the piston head portion on the head side chamber side by the amount of the rod portion of the piston. .. As a result, the forward force generated at the head-side chamber-side end surface of the piston head portion due to the ratio of the area of the head-side chamber-side end surface of the piston head portion to the rod-side chamber-side end surface area of the piston head portion It is possible to compensate for the difference between the retreating force generated on the end surface of the head portion on the rod side chamber side by the pressurizing portion. As a result, when performing the meter-out control, it is possible to prevent the piston from advancing in an uncontrollable state up to a position where the forward force and the backward force are balanced.

In this case, preferably, the control unit connects the rod side chamber and the pressurizing unit by the switching unit at a predetermined timing before the injection of the molten metal by the plunger is started, and the rod side chamber is heated by the pressurizing unit for a predetermined time. It is configured to perform pressure control. According to this structure, since the pressure of the hydraulic oil in the rod-side chamber can be reliably reached to the desired pressure by the pressurization of the pressurizing unit, the forward force generated on the end face of the head portion of the piston on the head-side chamber side is The pressurizing portion can reliably compensate for a difference between the piston head portion and the retracting force generated on the end surface on the rod side chamber side. Further, since the pressurization by the pressurization unit is stopped after the lapse of a predetermined time, even if the connection between the rod-side chamber and the pressurization unit is not interrupted by the switching unit, the pressure in the rod-side chamber becomes unstable due to the pressurization unit. Can be suppressed.

In the injection device including the switching unit and the tank, preferably, the switching unit is a connection between the rod side chamber and the pressurizing unit, a connection between the rod side chamber and the tank, and a connection between the rod side chamber and the pressing unit and the tank. It includes a switching valve for switching between shutting off. According to this structure, the single switching valve can cut off the connection between the rod side chamber and the pressurizing section and connect the rod side chamber and the tank, thus suppressing an increase in the number of parts of the injection device. In addition, it is possible to prevent the structure of the injection device from becoming complicated.

In the injection device including the switching valve and the tank, preferably, the switching unit includes a first switching valve that switches connection and disconnection between the rod side chamber and the pressurizing unit, and connection and connection between the rod side chamber and the tank. The control unit includes a second switching valve that switches the cutoff, and is configured to perform control for switching the first switching valve and the second switching valve in synchronization with each other. According to this structure, when a single switching valve is used, the functions required for the single switching valve can be divided into the first switching valve and the second switching valve, so that the switching of the injection device can be performed. It is possible to prevent the valve structure from becoming complicated. As a result, in the meter-out control, the piston can be stably advanced, and the complication of the structure of the switching valve of the injection device can be suppressed.

In the injection device according to the first aspect, it is preferable that the injection device according to the first aspect further includes a pressure increasing unit that increases the pressure of the head side chamber by supplying hydraulic oil to the head side chamber before the injection of the molten metal by the plunger is completed. The section is provided separately from the pressure boosting section, and is configured to pressurize the rod side chamber before the injection of the molten metal by the plunger is started. According to this structure, as compared with the case where the pressure booster and the switching unit are connected to pressurize the rod side chamber by the pressure booster,
Since the pressurizing unit can be arranged near the switching unit, the pressing unit and the switching unit can be easily connected.

In the injection device according to the first aspect, it is preferable that the injection device according to the first aspect further includes a pressure increasing portion that increases the pressure of the head side chamber by supplying hydraulic oil to the head side chamber before the injection of the molten metal by the plunger is completed. The booster is also provided as a pressurizer, and is configured to pressurize the rod-side chamber when the injection of molten metal by the plunger is started. With this configuration,
Since it is possible to suppress an increase in the number of parts as compared with the case where the pressure boosting unit and the pressure applying unit are separately provided, it is possible to prevent the configuration of the injection device from becoming complicated.

In the injection device according to the first aspect, it is preferable that the pump line that supplies the hydraulic oil to the rod side chamber, the flow path that connects the switching unit and the pump line, and the flow path that is disposed on the upstream side of the pump line. And a check valve. According to this structure, the hydraulic oil pressurized by the pressurizing unit can be prevented from flowing to the pump line through the flow path, so that the hydraulic oil can be reliably supplied from the pressurizing unit to the rod side chamber. be able to.

A die casting machine according to a second aspect of the present invention is a sleeve having a cylindrical shape having a pouring port through which the molten metal is poured by a pouring mechanism, a plunger for injecting the molten metal poured into the sleeve, and a plunger inside the sleeve. The injection device includes a piston connected to the plunger, a cylinder containing the piston, a cylinder including a cylinder chamber in which the internal space is divided into a rod side chamber and a head side chamber by the piston, and a plunger. Before the injection of molten metal is started, it includes a pressurizing unit for pressurizing the rod-side chamber, and a switching unit for switching connection or disconnection between the rod-side chamber and the pressurizing unit, and the switching unit includes the rod-side chamber and the pressurizing unit. It is located between.

In the die casting machine according to the second aspect of the present invention, as described above, the switching unit that switches connection or disconnection between the rod side chamber and the pressurizing unit is provided. The switching unit is arranged between the rod side chamber and the pressure unit. As a result, when performing meter-out control, even if the hydraulic oil in the rod-side chamber is discharged to reduce the pressure in the rod-side chamber, the connection between the rod-side chamber and the pressurizing unit is blocked by the switching unit. The pressure portion can prevent the rod side chamber from being pressurized. Therefore, when performing the meter-out control, even if the pressure of the rod-side chamber is reduced by discharging the hydraulic oil supplied to the rod-side chamber, it is possible to avoid pressurizing the rod-side chamber by the pressurizing unit. .. That is, when the meter-out control is performed, it is possible to prevent the pressure change in the rod-side chamber from becoming unstable. As a result, it is possible to obtain a die casting machine that can stably move the piston forward in the meter-out control.

According to the present invention, as described above, the piston can be stably advanced in the meter-out control.

It is the figure which showed typically the whole structure of the die casting machine by 1st Embodiment. It is the figure which showed the state of the pressurization process typically in the injection device by 1st Embodiment. FIG. 3 is a diagram schematically showing states of a low speed injection process and a high speed injection process in the injection device according to the first embodiment. FIG. 5 is a diagram schematically showing a state of a pressure boosting injection process in the injection device according to the first embodiment. It is the figure which showed typically the state of the return process in the injection device by 1st Embodiment. It is a flow chart showing injection processing of a control device in an injection device by a 1st embodiment. It is the figure which showed the state of the pressurization process typically in the injection device by 2nd Embodiment. It is the figure which showed typically the state of the low-speed injection process in the injection device by 2nd Embodiment. It is the figure which showed typically the state of the pressurization process in the injection device by 3rd Embodiment.

Embodiments embodying the present invention will be described below with reference to the drawings.

[First Embodiment]
The configuration of the die casting machine 1 according to the first embodiment will be described with reference to FIGS. 1 to 5.

(Structure of die casting machine)
As shown in FIG. 1, the die casting machine 1 is a horizontal machine in which a moving die 21 is horizontally moved. Further, the die casting machine 1 is a cold chamber type machine, and a molten metal (liquid metal) is placed in the die 2 (cavity C formed by the moving die 21 and the fixed die 22) attached to the die casting machine 1. It is configured to manufacture a die cast product (molded product) by injecting a material).

The die casting machine 1 includes a mold 2, a sleeve 3, a pouring mechanism 4, a lid mechanism 5, a plunger 6, an injection device 7, and a control device 8. The control device 8 is an example of the "control unit" in the claims.

Here, in the following description, the vertical direction is the Z direction, and of the horizontal directions, the direction in which the plunger 6 extends is the X direction. Further, of the X directions, the moving direction of the plunger 6 when injecting the molten metal is the X1 direction, and the opposite direction of the X1 direction is the X2 direction.

The mold 2 is configured to form a cavity C (hollow portion) for molding a die cast product (molded product).

Specifically, the mold 2 includes a movable mold 21 and a fixed mold 22. The fixed die 22 is fixed to the fixed die plate 23. The movable mold 21 is attached to the movable die plate 24 so as to be movable in a direction (X direction) in which the movable mold 21 comes into contact with or separates from the fixed mold 22. The cavity C is formed by bringing the moving mold 21 into contact with the fixed mold 22.

The sleeve 3 is configured to accommodate the plunger 6 so as to be movable in the X direction and to pour the molten metal.

Specifically, the sleeve 3 includes a pouring port 31 and a molten metal passage 32. The sleeve 3 has a tubular shape. The sleeve 3 extends in the X direction. The pouring port 31 is provided for pouring the molten metal into the molten metal passage 32 by the pouring mechanism 4. The pouring port 31 penetrates the portion of the sleeve 3 on the Z1 direction side in the Z direction. The molten metal passage 32 is a through hole that penetrates the sleeve 3 in the X direction. The molten metal passage 32 communicates with the cavity C in the X1 direction.

The pouring mechanism 4 is configured to draw (melt) a liquid metal material (molten metal) from a holding furnace (not shown) and supply it to the sleeve 3.

Specifically, the pouring mechanism 4 includes a ladle 41 and an arm 42. The ladle 41 is configured to pump liquid metal material from the holding furnace. The arm 42 is configured to move the ladle 41 to the pouring port 31 of the sleeve 3 and tilt the ladle 41 to pour the molten metal into the sleeve 3.

The lid mechanism 5 is configured to close the pouring port 31 after pouring the molten metal into the sleeve 3 by the pouring mechanism 4.

Specifically, the lid mechanism 5 includes a lid portion 51 and an arm 52. The lid portion 51 has a shape that follows the shape of the pouring hole 31 when viewed from the Z1 direction. The lid 51 is arranged at the tip of the arm 52. The arm 52 is configured to move the lid portion 51 to the pouring port 31.

The plunger 6 is configured to inject the molten metal poured into the sleeve 3.

Specifically, the plunger 6 has a plunger tip 61 and a plunger rod 62. The plunger tip 61 is a member that comes into contact with the molten metal. The plunger tip 61 is detachably attached to the end of the plunger rod 62 on the X1 direction side. The plunger rod 62 is a member that transmits the driving force generated in the injection device 7 to the plunger tip 61. The plunger rod 62 has a rod shape extending in the X direction. The plunger rod 62 is connected to the injection device 7 at the end on the X2 direction side.

(Injection device)
The injection device 7 is configured to inject the molten metal into the cavity C by moving the plunger 6. That is, the injection device 7 is configured to reciprocate the plunger 6 in the X direction within the sleeve 3. Specifically, as shown in FIG. 2, the injection device 7 includes an accumulator (ACC) 70, a piston 71, a cylinder 72, a tank 73, a position sensor 74, a pressure booster 75, and a pressurizer. It includes a pressure section 76, a pump line 77, a check valve 78, and a switching valve 79. The switching valve 79 is an example of the "switching unit" in the claims. The pump line 77 is an example of the "hydraulic oil supply source" in the claims.

Further, the injection device 7 has a plurality of flow paths that connect each of a plurality of configurations. The plurality of flow paths include a first flow path 91, a second flow path 92, a third flow path 93, a fourth flow path 94, a fifth flow path 95, a sixth flow path 96 and a seventh flow path 97, respectively. Have The fourth flow path 94 is an example of the "flow path" in the claims.

The first flow passage 91 is a flow passage that connects the accumulator 70 and the cylinder 72. The second flow path 92 is a flow path that branches from the first flow path 91 and connects the accumulator 70 and the pressure booster 75. The third flow path 93 is a flow path that joins the first flow path 91 and connects the pressure booster 75 and the cylinder 72. The fourth flow path 94 is a flow path that connects the pump line 77 and the switching valve 79. The fifth flow path 95 is a flow path that branches from the fourth flow path 94 and connects the pressurizing unit 76 and the switching valve 79. The sixth flow path 96 is a flow path that connects the switching valve 79 and the cylinder 72. The seventh flow passage 97 is a flow passage that connects the switching valve 79 and the tank 73.

The accumulator 70 is configured to supply hydraulic oil for moving the piston 71 in the X1 direction to the cylinder 72. That is, the accumulator 70 is a hydraulic pressure source.

The piston 71 is configured to reciprocate in the cylinder 72 in the X direction. Specifically, the piston 71 has a head portion 71a and a rod portion 71b. The head portion 71a has a columnar shape. In the Z direction, the length of the head portion 71a is larger than that of the rod portion 71b. The end of the head portion 71a on the X1 direction side is connected to the end of the rod portion 71b on the X2 direction side. The rod portion 71b has a columnar shape. An end portion of the rod portion 71b on the X2 direction side is connected to a central portion of the head portion 71a in the Z1 direction.

In the Z direction, the area of the end surface of the head portion 71a on the rod side chamber S1 side is smaller than the area of the end surface of the head portion 71a on the head side chamber S2 side by the amount of the rod portion 71b.

The piston 71 is connected to the plunger 6. Specifically, the end of the rod portion 71b on the X1 direction side is attached to the end of the plunger rod 62 on the X2 direction side. As a result, the plunger 6 is configured to be movable in association with the movement of the piston 71 in the X direction.

The cylinder 72 is configured so that hydraulic oil for moving the piston 71 in the X1 direction and hydraulic oil for moving the piston 71 in the X2 direction can flow in. Specifically, the cylinder 72 has a piston 71 built therein and has a cylinder chamber S divided into a rod side chamber S1 and a head side chamber S2 by the piston 71. The cylinder 72 has a first opening 72a and a second opening 72b.

The cylinder chamber S is a space formed in the cylinder 72. In the cylinder chamber S, a head portion 71a and a rod portion 71b of a piston 71 contained in the cylinder 72 are arranged.

The head side chamber S2 is a space on the X2 direction side of the head portion 71a of the piston 71 in the cylinder chamber S. The hydraulic oil from the accumulator 70 or the hydraulic oil from the pressure booster 75 flows into the head side chamber S2. As a result, a forward force that moves the piston 71 in the X1 direction is generated in the head portion 71a of the piston 71. The advancing force is a force that moves the piston forward (presses in the X1 direction) when the pressure of the hydraulic oil in the head side chamber S2 is applied to the end surface of the head portion 71a of the piston 71 on the head side chamber S2 side.

The volume of the head side chamber S2 increases as the piston 71 moves (forwards) in the X1 direction. The volume of the head side chamber S2 becomes smaller as the piston 71 moves (retracts) in the X2 direction.

The rod side chamber S1 is a space on the X1 direction side of the head portion 71a of the piston 71 in the cylinder chamber S. The hydraulic oil from the switching valve 79 flows into the rod side chamber S1. As a result, a retreating force that moves the piston 71 in the X2 direction is generated in the head portion 71a of the piston 71. The retreat force is a force that causes the piston to retreat (push in the X2 direction) when the pressure of the hydraulic oil in the rod side chamber S1 is applied to the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side.

The volume of the rod side chamber S1 becomes smaller as the piston 71 moves (forwards) in the X1 direction. The volume of the rod side chamber S1 increases as the piston 71 moves (retracts) in the X2 direction.

The first opening 72a connects the accumulator 70 or the pressure booster 75 to the head side chamber S2 of the cylinder 72. At the first opening 72a, the working oil from the accumulator 70 or the working oil from the pressure booster 75 flows into the head side chamber S2. The first opening 72a is formed at the end of the cylinder 72 on the X2 direction side. The first opening 72a is a through hole that penetrates the cylinder 72 in the X direction. The first opening 72a is connected to the downstream end of the first flow passage 91.

The second opening 72b connects the rod side chamber S1 of the cylinder 72 and the switching valve 79. At the second opening 72b, the hydraulic oil in the rod side chamber S1 flows out to the switching valve 79 or the hydraulic oil from the switching valve 79 flows into the rod side chamber S1. The second opening 72b is formed at the end of the cylinder 72 on the Z2 direction side. The second opening 72b is arranged on the X1 direction side. The second opening 72b is a through hole that penetrates the cylinder 72 in the Z direction. The second opening 72b is connected to the downstream end of the sixth flow path 96.

The cylinder 72 is configured to be able to connect the rod portion 71b of the piston 71 arranged inside the cylinder 72 and the plunger 6 arranged outside the cylinder 72. Specifically, the cylinder 72 has an insertion hole 72c. The rod portion 71b of the piston 71 is inserted through the insertion hole 72c. The insertion hole 72c is formed at the end of the cylinder 72 on the X1 direction side. The insertion hole 72c is a through hole that penetrates the cylinder 72 in the X direction. As described above, the rod portion 71b of the piston 71 has a portion protruding from the cylinder 72 in the X1 direction.

The tank 73 is configured to store the hydraulic oil discharged from the rod side chamber S1 of the cylinder 72. The tank 73 stores the hydraulic oil discharged from the rod side chamber S1 via the sixth flow path 96, the switching valve 79 and the seventh flow path 97.

The position sensor 74 is configured to detect the protruding amount of the rod portion 71b of the piston 71 protruding from the cylinder 72. The position sensor 74 is configured to indirectly detect the tip position of the plunger 6 based on the detected protrusion amount of the rod portion 71b. The position sensor 74 is electrically connected to the control device 8.

The pressure increasing unit 75 is configured to increase the pressure in the head side chamber S2 by supplying hydraulic oil to the head side chamber S2 before the injection of the molten metal by the plunger 6 is completed. That is, the pressure booster 75, after filling the cavity C with the molten metal, increases the pressure of the working oil in the head side chamber S2 (pressure boost) to generate a forward force that further moves the piston 71 in the X1 direction. .. The pressure booster 75 is connected to the accumulator 70 via a first flow passage 91 and a second flow passage 92 in which an on-off valve is arranged. The pressure booster 75 is connected to the head side chamber S2 via the third flow passage 93 and the first flow passage 91 in which the check valve is arranged. Although not shown, the pressure boosting portion 75 has a pressure boosting cylinder and a pressure boosting piston.

<Pressure part>
The pressurization unit 76 is configured to pressurize the rod side chamber S1 before the injection of the molten metal by the plunger 6 is started. That is, the pressurizing unit 76 is provided separately from the pressurizing unit 75, and is configured to pressurize the rod side chamber S1 before the injection of the molten metal by the plunger 6 is started. In this way, the pressurizing unit 76 pressurizes the hydraulic oil in the rod-side chamber S1 so as to prevent the piston 71 from jumping out in the uncontrollable direction in the X1 direction when starting the meter-out control. Is configured to be large.

Specifically, the pressurizing unit 76 has a pressurizing piston 76a and a pressurizing cylinder 76b. The pressurizing piston 76a is configured to reciprocate in the pressurizing cylinder 76b in the X direction. The pressurizing piston 76 a has a head portion 171 and a rod portion 172. The cylinder 72 contains the entire piston 71. A transmission port 173 is formed at the end of the pressurizing cylinder 76b on the X1 direction side. The transmission port 173 is configured to transmit the pressure applied by the pressurizing piston 76a to the rod side chamber S1. The transmission port 173 is a through hole that penetrates the pressurizing cylinder 76b in the X direction.

The pressure of the hydraulic oil in the rod side chamber S1 is increased by moving (advancing) the pressurizing piston 76a in the X1 direction. The pressure of the hydraulic oil in the rod side chamber S1 returns to the original pressure by moving (retracting) the pressurizing piston 76a in the X2 direction. The pressurizing piston 76a moves (forwards) in the X1 direction by the hydraulic oil supplied from a hydraulic pressure source (not shown). Further, the pressurizing piston 76a moves (reverses) in the X2 direction by the hydraulic oil supplied from a hydraulic pressure source (not shown).

The pressurizing unit 76 is electrically connected to the control device 8. Here, the control device 8 is configured to control the forward movement and the backward movement of the pressurizing piston 76a by the hydraulic oil supplied from a hydraulic pressure source (not shown).

<Pump line>
The pump line 77 is configured to supply hydraulic oil for moving the piston 71 in the X2 direction to the cylinder 72. That is, the pump line 77 is a pump that pumps hydraulic oil from the tank 73. The pump line 77 supplies hydraulic oil to the rod side chamber S1 via the fourth flow path 94, the switching valve 79 and the sixth flow path 96.

<Check valve>
The check valve 78 is configured to prevent the hydraulic oil pressurized by the pressurizing unit 76 from flowing into the pump line 77 when the pressurizing unit 76 pressurizes. Specifically, the check valve 78 is a check valve. The check valve 78 is arranged on the upstream side of the pump line 77 in the fourth flow path 94. Here, the check valve 78 is arranged between the switching valve 79 and the pump line 77.

<Switching valve>
The switching valve 79 is configured to switch connection or disconnection between the rod side chamber S1 and the pressurizing unit 76. Further, the switching valve 79 is configured to switch connection or disconnection between the rod side chamber S1 and the tank 73. That is, the switching valve 79 switches between the connection between the rod side chamber S1 and the pressurizing unit 76, the connection between the rod side chamber S1 and the tank 73, and the disconnection of the connection between the rod side chamber S1 and the pressurizing unit 76 and the tank 73. It is a three-way valve.

Specifically, the switching valve 79 switches to the first connection state in which the rod side chamber S1 and the pressurizing unit 76 are connected and the connection between the rod side chamber S1 and the tank 73 is cut off. The switching valve 79 connects the rod side chamber S1 and the tank 73 and switches to a second connection state in which the connection between the rod side chamber S1 and the pressurizing unit 76 is cut off. The switching valve 79 switches to a third connection state in which the connection between the rod side chamber S1 and the pressurizing unit 76 is blocked and the connection between the rod side chamber S1 and the tank 73 is blocked. In this way, the rod-side chamber S1 and the pressurizing section 76 are shut off while the switching valve 79 connects the rod-side chamber S1 and the tank 73.

The switching valve 79 is a hydraulic servo valve as a three-way valve. Here, the switching valve 79 has a function as a flow control valve that controls the amount of hydraulic oil discharged from the rod side chamber S1 to the tank 73 in the second connected state. Further, the switching valve 79 has a function as an opening/closing valve that disconnects the connection between the rod side chamber S1 and the pressurizing portion 76 in the first and third connection states.

The switching valve 79 of the first embodiment is arranged at a position where the connection between the rod side chamber S1 and the pressurizing portion 76 can be shut off when reducing the pressure of the hydraulic oil in the rod side chamber S1. Specifically, the switching valve 79 is arranged between the rod side chamber S1 and the pressurizing section 76. That is, the switching valve 79 is arranged on the downstream side of the pressurizing section 76 and on the upstream side of the rod side chamber S1 in the flow of the hydraulic oil flowing from the pressurizing section 76 to the rod side chamber S1.

The switching valve 79 is electrically connected to the control device 8.

(Control device)
The injection device 7 includes the control device 8 described above. The controller 8 is configured to control the driving of each part of the die casting machine 1. The control device 8 is electrically connected not only to the injection device 7 but also to each part of the die casting machine 1. The control device 8 includes, for example, a CPU (Central Processing Unit) and a storage unit such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

The storage unit stores a control program for controlling the driving of each unit of the die casting machine 1. The control program has an injection processing unit 8a having a timer unit 81. The control device 8 controls each unit of the injection device 7 by the injection processing unit 8a. The control device 8 drives the pressing unit 76 by the timer unit 81.

The injection processing unit 8a is configured to perform an injection process by controlling each unit of the injection device 7 by the control device 8. The injection process includes a pressurization process (see FIG. 2), a low speed injection process (see FIG. 3), a high speed injection process (see FIG. 3), a pressure boosting injection process (see FIG. 4) and a return process (see FIG. 5). doing. In the injection process, a pressurizing process, a low-speed injection process, a high-speed injection process, a pressure-increasing injection process, and a restoration process are performed in this order, and the injection process is repeated by returning to the compression process after the restoration process.

The injection processing unit 8a has a meter-out control and a pressurization control for controlling each unit of the injection device 7. The meter-out control is a control in which the forward force generated on the end surface of the head portion 71a of the piston 71 on the head side chamber S2 side is suppressed by the backward force generated on the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side. The pressurization control is performed by pressurizing the rod-side chamber S1 by the pressurizing unit 76 before the start of the meter-out control. This control compensates for the difference between the head portion 71a of the piston 71 and the retracting force generated at the end surface on the rod side chamber S1 side.

The timer unit 81 is configured to pressurize the rod side chamber S1 to a constant pressure by the pressurizing unit 76 for a predetermined time. In the rod side chamber S1, the retreating force generated in the hydraulic oil in the rod side chamber S1 due to the pressurization of the rod side chamber S1 by the pressurizing unit 76 is adjusted to the forward force generated in the hydraulic oil in the head side chamber S2 for a predetermined time. It is the time to hold the pressure of the hydraulic oil. Further, the predetermined time is managed by the control device 8.

As shown in FIGS. 2 to 5, the control device 8 is configured to switch between the meter-out control and the pressurization control by the switching valve 79 to control the movement of the piston 71 and the movement of the plunger 6 interlocking with the piston 71. Has been done.

<Pressure process>
As shown in FIG. 2, the control device 8 is configured to perform control to connect the rod side chamber S1 and the pressurizing portion 76 by the switching valve 79 at a predetermined timing before the injection of the molten metal by the plunger 6 is started. Has been done. That is, the control device 8 is configured to perform the control of pressurizing the rod side chamber S1 by the pressurizing unit 76 in the pressurizing process started at a predetermined timing.

Specifically, the control device 8 connects the rod side chamber S1 and the pressurizing portion 76 by the switching valve 79 at a predetermined timing before the injection of the molten metal by the plunger 6 is started, and the rod by the pressurizing portion 76 is connected. The side chamber S1 is configured to be pressurized for a predetermined time.

Here, the control device 8 is configured to cut off the connection between the rod side chamber S1 and the tank 73 and connect the rod side chamber S1 and the pressurizing portion 76 by the switching valve 79 at a predetermined timing. Further, the control device 8 is configured such that the timer unit 81 starts the pressurization by the pressurizing unit 76 for a predetermined time at a predetermined timing. At this time, the pressurizing unit 76 and the rod-side chamber S1 communicate with each other. As a result, the pressure of the hydraulic oil in the rod side chamber S1 is increased by the pressurizing portion 76. The tank 73 and the rod side chamber S1 are not in communication with each other. As a result, the hydraulic oil pressurized by the pressurization unit 76 is not discharged to the tank 73.

The control device 8 is configured to obtain a predetermined timing by performing back calculation from the start time of injection of the molten metal by the plunger 6. Here, the predetermined timing is a time from the end of the return process to the start of the low-speed injection process. The predetermined timing is preferably closer to the start point of the low-speed injection step than the intermediate point between the end point of the returning step and the start point of the low-speed injection step. Here, the start time of the injection of the molten metal by the plunger 6 is the time when the low-speed injection process (see FIG. 3) of the injection process is started.

The length of the predetermined time is set in accordance with the time from the predetermined timing to the start of injection of the molten metal by the plunger 6. The length of the predetermined time may be the same as the time from the predetermined timing to the start time of the injection of the molten metal by the plunger 6, may be large, or may be small. The length of the predetermined time is preferably around the time from the predetermined timing to the start of injection of the molten metal by the plunger 6.

<Low-speed injection process>
As shown in FIG. 3, the control device 8 of the first embodiment controls the switching valve 79 to cut off the connection between the rod side chamber S1 and the pressurizing unit 76 when the injection of the molten metal by the plunger 6 is started. It is configured. That is, the control device 8 is configured to perform control that avoids pressurization of the rod side chamber S1 by the pressurizing unit 76 during the low-speed injection process in which the meter-out control is started.

Specifically, when the injection of the molten metal by the plunger 6 is started, the control device 8 shuts off the connection between the rod side chamber S1 and the pressurizing section 76 by the switching valve 79 and causes the switching valve 79 to switch the rod side chamber S1. And the tank 73 are connected to each other. That is, the control device 8 is configured to control the rod side chamber S1 and the pressurizing unit 76 not to communicate with each other and the rod side chamber S1 and the tank 73 to communicate with each other when the pressure reduction of the rod side chamber S1 is started. ing. Here, the rod side chamber S1 is not pressurized by the pressure unit 76 because the pressure unit 76 and the rod side chamber S1 are not communicated with each other. The tank 73 and the rod side chamber S1 communicate with each other. As a result, the hydraulic oil in the rod side chamber S1 is discharged to the tank 73.

Here, since the control device 8 performs the meter-out control, the switching valve 79 cuts off the connection between the pressurizing unit 76 and the rod-side chamber S1 and controls the discharge amount of the hydraulic oil from the rod-side chamber S1 to the tank 73. It is configured to control. That is, in the low-speed injection process, the control device 8 adjusts the retracting force generated on the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side without communicating the rod side chamber S1 and the pressurizing section 76, and adjusts the piston 71. Is configured to be controlled to move forward. Here, the retracting force generated on the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side is adjusted by discharging the hydraulic oil from the rod side chamber S1 to the tank 73 and changing the pressure in the rod side chamber S1. ..

<High-speed injection process>
As shown in FIG. 3, similarly to the low speed injection process, the control device 8 controls the switching valve 79 to disconnect the pressurizing unit 76 from the rod side chamber S1 during the high speed injection process in which the meter-out control is performed. Is configured to do. That is, in the high-speed injection process, the control device 8 adjusts the pressure in the rod-side chamber S1 by discharging the hydraulic oil in the rod-side chamber S1 to the tank 73 without communicating the rod-side chamber S1 with the pressurizing unit 76. Then, the piston 71 is controlled to move forward.

Here, the forward speed of the piston 71 in the high-speed injection process is higher than the forward speed of the piston 71 in the low-speed injection process. Further, the control device 8 is configured to determine the start of the high-speed injection process based on the tip position of the plunger 6 that is indirectly detected by the position sensor 74.

<Intensified injection process>
As shown in FIG. 4, similarly to the low speed injection process, the control device 8 cuts off the connection between the pressurizing unit 76 and the rod side chamber S1 by the switching valve 79 during the pressure increase injection process in which the meter-out control is performed. It is configured to control. That is, in the pressure boosting injection process, the control device 8 discharges the hydraulic oil in the rod side chamber S1 to the tank 73 without communicating the rod side chamber S1 and the pressurizing unit 76, thereby reducing the pressure in the rod side chamber S1. It is configured to be adjusted to perform control for advancing the piston 71.

Here, the hydraulic oil supplied to the head side chamber S2 is the hydraulic oil supplied from the pressure booster 75. The pressure of the hydraulic oil supplied from the pressure booster 75 is higher than the pressure of the hydraulic oil supplied from the accumulator 70. Further, the control device 8 is configured to determine the start of the pressure boosting injection process based on the tip position of the plunger 6 that is indirectly detected by the position sensor 74.

<Return process>
As shown in FIG. 5, the control device 8 is configured to control the switching line 79 to connect the pump line 77 and the rod side chamber S1 during the return process. That is, in the return process, the control device 8 controls the piston 71 to retract and return to the return position by supplying the hydraulic oil of the pump line 77 to the rod side chamber S1 without communicating the rod side chamber S1 with the tank 73. Is configured to do.

Here, the control device 8 is configured to determine the return position of the piston 71 based on the tip position of the plunger 6 that is indirectly detected by the position sensor 74.

(Injection process)
The injection process will be described below with reference to FIG. The injection process is a process of injecting the molten metal into the cavity C of the mold 2 by the plunger 6 that is interlocked with the piston 71.

First, steps S1 to S3 are steps for performing a pressurizing step of pressurizing the rod side chamber S1 in advance.

In step S1, the control device 8 determines whether it is a predetermined timing. That is, it is determined whether or not the pressurization of the rod side chamber S1 is started. If it is the predetermined timing, the process proceeds to step S2, and if it is not the predetermined timing, step S1 is repeated. In step S2, the controller 8 causes the pressurizing unit 76 to pressurize the rod-side chamber S1. That is, the timer 81 pressurizes the rod-side chamber S1 for a predetermined time. As a result, the forward force generated on the end surface of the head portion 71a of the piston 71 on the head side chamber S2 side and the backward force on the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side are balanced.

In step S3, the control device 8 determines whether or not a predetermined time has elapsed. When the predetermined time has elapsed, the process proceeds to step S4, and when the predetermined time has not elapsed, step S3 is repeated.

Steps S4 and S5 are steps for performing the low-speed injection step of moving the plunger 6 at a low speed to inject the molten metal.

In step S4, the control device 8 shuts off the pressurization by the pressurization unit 76. That is, by switching the switching valve 79 by the control device 8, the rod side chamber S1 and the tank 73 are communicated with each other without the rod side chamber S1 and the pressurizing section 76 being communicated with each other. In step S5, the control device 8 starts low-speed injection. Here, in the low-speed injection process, the piston 71 is advanced by the meter-out control.

Steps S6 and S7 are steps for performing a high-speed injection step of moving the plunger 6 at high speed to inject the molten metal.

In step S6, the control device 8 determines whether or not it is the high-speed injection start position. If it is the high-speed injection start position, the process proceeds to step S7, and if it is not the high-speed injection start position, step S6 is repeated. In step S7, the control device 8 starts high-speed injection. Here, in the high-speed injection process, the piston 71 is advanced by the meter-out control.

Steps S8 to S10 are steps for performing a boosting injection step of injecting the molten metal by the plunger 6 in a state where the pressure in the head side chamber S2 is boosted by the booster 75.

In step S8, the control device 8 determines whether or not the boosted pressure injection start position is reached. If it is the pressure boosting injection start position, the process proceeds to step S9, and if it is not the pressure boosting start position, step S8 is repeated. In step S9, the controller 8 starts the boosted pressure injection. Here, in the boosted pressure injection process, the piston 71 is advanced by the meter-out control.

In step S10, the control device 8 determines whether or not the injection end position is reached. That is, the control device 8 determines whether or not the injection of the plunger 6 is completed. If it is the injection end position, the process proceeds to step S11. If it is not the injection end position, step S10 is repeated.

Steps S11 and S12 are steps for performing a returning step of returning the plunger 6 to the returning position (initial position).

In step S11, the control device 8 causes the piston 71 to retract. That is, the plunger 6 interlocking with the piston 71 moves backward by supplying hydraulic oil from the pump line 77 to the rod side chamber S1 to move the piston 71 backward. In step S12, the control device 8 determines whether or not the position is the return position. If it is the return position, the process returns to step S1, and if it is not the return position, step S12 is repeated. At this time, the pressure of the hydraulic oil in the rod side chamber S1 becomes the pressure of the hydraulic oil in the pump line 77.

(Effects of the first embodiment)
The effects of the first embodiment will be described.

In the first embodiment, as described above, the injection device 7 is provided with the switching valve 79 that switches connection or disconnection between the rod side chamber S1 and the pressurizing portion 76. Then, the switching valve 79 is arranged between the rod side chamber S1 and the pressurizing portion 76. As a result, when performing meter-out control, when the hydraulic oil in the rod-side chamber S1 is discharged to reduce the pressure in the rod-side chamber S1, the connection between the rod-side chamber S1 and the pressurizing portion 76 is shut off by the switching valve 79. By doing so, it is possible to prevent the rod side chamber S1 from being pressurized by the pressure unit 76. Therefore, when the pressure in the rod-side chamber S1 is reduced by discharging the hydraulic oil supplied to the rod-side chamber S1 during the meter-out control, the rod-side chamber S1 is pressurized by the pressurizing unit 76. Can be avoided. As a result, when performing the meter-out control, it is possible to prevent the pressure change in the rod-side chamber S1 from becoming unstable, so that the piston 71 can be stably advanced in the meter-out control. In addition, since the piston 71 can be stably advanced in the meter-out control, the plunger 6 can be stably advanced, and thus the molten metal injection can be stabilized. Further, even when the pressure of the hydraulic oil in the rod side chamber S1 becomes larger than that in the pressurizing portion 76, the switching valve 79 cuts off the connection between the rod side chamber S1 and the pressurizing portion 76, so that the hydraulic oil in the rod side chamber S1 is It is possible to prevent the backflow to the pressurizing section 76 due to.

Further, in the first embodiment, as described above, in the injection device 7, when the injection of the molten metal by the plunger 6 is started, the switching valve 79 disconnects the rod side chamber S1 from the pressurizing portion 76. A control device 8 for performing the above is provided. Thus, when the molten metal is injected by the plunger 6 by the meter-out control, it is possible to prevent the pressurizing portion 76 from pressurizing the rod side chamber S1 from the start of the injection of the molten metal by the plunger 6. Therefore, while the molten metal is being injected by the plunger 6, it is possible to prevent the pressure of the hydraulic oil in the rod side chamber S1 from becoming unstable due to the pressurizing portion 76. As a result, while the molten metal is being injected by the plunger 6, the piston 71 can be stably moved forward to stabilize the molten metal injection.

Further, in the first embodiment, as described above, the injection device 7 is provided with the tank 73 from which the hydraulic oil in the rod side chamber S1 is discharged. When the injection of the molten metal by the plunger 6 is started, the control device 8 shuts off the connection between the rod side chamber S1 and the pressurizing section 76 by the switching valve 79, and switches the rod side chamber S1 and the tank 73 by the switching valve 79. It is configured to control connection. Accordingly, the connection between the rod-side chamber S1 and the pressurizing unit 76 is blocked by the switching valve 79 while the meter-out control is being performed, so that the pressurizing unit 76 does not reliably pressurize the rod-side chamber S1. be able to. As a result, it is possible to prevent the pressure of the hydraulic oil in the rod side chamber S1 from becoming unstable due to the pressurizing portion 76 while the meter-out control is being performed. Further, unlike the case of performing meter-in control in which only the forward force of the hydraulic oil in the head side chamber S2 is controlled to move the piston 71 forward, in the meter-out control, the forward force generated in the hydraulic oil in the head side chamber S2 is applied to the rod side chamber S1. It can be suppressed by the backward force generated in the hydraulic oil inside. Therefore, unless the forward force is precisely controlled, unlike the meter-in control in which the piston 71 advances (jumps out) in an uncontrollable state, the meter-out control does not require precise control of the forward force. As a result, it is not necessary to provide a plurality of valves required for finely adjusting the advancing force on the upstream side of the head side chamber S2 of the cylinder 72, and thus it is possible to suppress an increase in the number of parts of the injection device 7. ..

Further, in the first embodiment, as described above, the control device 8 connects the rod side chamber S1 and the pressurizing portion 76 by the switching valve 79 at a predetermined timing before the injection of the molten metal by the plunger 6 is started. It is configured to control. As a result, the pressure of the hydraulic oil in the rod side chamber S1 can be increased by the pressurizing unit 76 at a predetermined timing. Here, in the Z direction, the area of the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side is larger than the area of the end surface of the head portion 71a of the piston 71 on the head side chamber S2 side by the amount of the rod portion 71b of the piston 71. Is also small. Therefore, it occurs on the end surface of the head portion 71a of the piston 71 on the head side chamber S2 side due to the ratio of the area of the head portion 71a of the piston 71 on the head side chamber S2 side to the area of the head portion 71a of the piston 71 on the rod side chamber S1 side. The difference between the forward force and the backward force generated on the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side can be compensated by the pressurizing portion 76. As a result, when performing the meter-out control, it is possible to prevent the piston 71 from advancing in an uncontrollable state up to a position where the forward force and the backward force are balanced.

Further, in the first embodiment, as described above, the control device 8 connects the rod side chamber S1 and the pressurizing portion 76 by the switching valve 79 at a predetermined timing before the injection of the molten metal by the plunger 6 is started. At the same time, the pressurizing unit 76 is configured to control the pressurization of the rod side chamber S1 for a predetermined time. As a result, the pressure of the hydraulic oil in the rod-side chamber S1 can be reliably reached to the desired pressure by the pressurization of the pressurizing unit 76, and therefore the forward force generated on the end surface of the head portion 71a of the piston 71 on the head-side chamber S2 side. It is possible to reliably compensate for the difference between the retracting force generated on the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side by the pressurizing portion 76. Further, since the pressurization by the pressurization unit 76 is stopped after the lapse of a predetermined time, even if the connection between the rod-side chamber S1 and the pressurization unit 76 is not cut off by the switching valve 79, the pressure in the rod-side chamber S1 remains unchanged. It is possible to suppress instability due to 76.

Further, in the first embodiment, as described above, the switching valve 79 is connected to the rod side chamber S1 and the pressurizing unit 76, the rod side chamber S1 and the tank 73, and the rod side chamber S1 and the pressurizing unit 76. And the connection with the tank 73 is cut off. As a result, the single switching valve 79 can cut off the connection between the rod side chamber S1 and the pressurizing section 76 and connect the rod side chamber S1 and the tank 73, so that the number of parts of the injection device 7 can be increased. In addition to being able to suppress, it can suppress that the structure of the injection device 7 becomes complicated.

In addition, in the first embodiment, as described above, the pressurizing unit 76 is provided separately from the pressurizing unit 75. The pressurizing unit 76 is configured to pressurize the rod side chamber S1 before the injection of the molten metal by the plunger 6 is started. As a result, the pressurizing unit 76 can be arranged near the switching valve 79 as compared with the case where the pressure increasing unit 75 and the switching valve 79 are connected to pressurize the rod side chamber S1 by the pressure increasing unit 75. Therefore, the pressurizing unit 76 and the switching valve 79 can be easily connected.

Further, in the first embodiment, as described above, the injection device 7 is provided with the check valve 78 arranged on the upstream side of the pump line 77 in the fourth flow path 94. This can prevent the hydraulic oil pressurized by the pressurizing unit 76 from flowing to the pump line 77 via the fourth flow path 94, so that the hydraulic oil can be reliably transferred from the pressurizing unit 76 to the rod side chamber S1. Can be supplied to.

[Second Embodiment]
Next, the configuration of the injection device 207 according to the second embodiment of the present invention will be described with reference to FIGS. 7 and 8. In the second embodiment, an example using a first switching valve 279a and a second switching valve 279b that are two-way valves will be described, unlike the first embodiment that uses the three-way valve switching valve 79. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

(Injection device)
As shown in FIG. 7, the injection device 207 of the second embodiment has an accumulator 70 (ACC), a piston 71, a cylinder 72, a tank 73, a position sensor 74, a pressure booster 75, and a pressurizer. 76, a pump line 77, a check valve 78, a first switching valve 279a and a second switching valve 279b. The first switching valve 279a and the second switching valve 279b are examples of the "switching unit" in the claims. The pump line 77 is an example of the "hydraulic oil supply source" in the claims.

Further, the injection device 207 has a plurality of flow paths that connect each of a plurality of configurations. The plurality of channels are the first channel 91, the second channel 92, the third channel 93, the fourth channel 294, the fifth channel 295, the sixth channel 296, the seventh channel 297, and It has an eighth channel 298. The fourth channel 294 is an example of the "channel" in the claims.

The first flow passage 91 is a flow passage that connects the accumulator 70 and the cylinder 72. The second flow path 92 is a flow path that branches from the first flow path 91 and connects the accumulator 70 and the pressure booster 75. The third flow path 93 is a flow path that joins the first flow path 91 and connects the pressure booster 75 and the cylinder 72. The fourth flow path 294 is a flow path that connects the pump line 77 and the first switching valve 279a. The fifth flow path 295 is a flow path that branches from the fourth flow path 294 and connects the pressurizing unit 76 and the switching valve 79. The sixth flow path 296 is a flow path that connects the first switching valve 279a and the seventh flow path 297. The seventh flow path 297 is a flow path that connects the second switching valve 279b and the cylinder 72. The eighth flow path 298 is a flow path that connects the second switching valve 279b and the tank 73.

<First switching valve and second switching valve>
The first switching valve 279a is configured to switch connection or disconnection between the rod side chamber S1 and the pressurizing unit 76. The second switching valve 279b is configured to switch connection or disconnection between the rod side chamber S1 and the tank 73. That is, each of the first switching valve 279a and the second switching valve 279b is a two-way valve. The first switching valve 279a and the second switching valve 279b are hydraulic servo valves (electromagnetic hydraulic switching valves), respectively.

(Control device)
The control device 8 of the second embodiment is configured to perform control for switching the first switching valve 279a and the second switching valve 279b in synchronization with each other. That is, the control device 8 is configured so that the first switching valve 279a connects the rod side chamber S1 and the pressurizing unit 76, and the second switching valve 279b controls the connection between the rod side chamber S1 and the tank 73. Has been done. Further, the control device 8 controls the first switching valve 279a to cut off the connection between the rod side chamber S1 and the pressurizing section 76 and the second switching valve 279b to connect the rod side chamber S1 and the tank 73. It is configured.

<Pressure process>
As shown in FIG. 7, the control device 8 controls the first switching valve 279a to connect the rod side chamber S1 and the pressurizing unit 76 at a predetermined timing before the injection of the molten metal by the plunger 6 is started. Is configured.

Specifically, the control device 8 cuts off the connection between the rod side chamber S1 and the tank 73 by the second switching valve 279b at a predetermined timing, and disconnects the rod side chamber S1 and the pressurizing unit 76 by the first switching valve 279a. Is configured to connect. Further, the control device 8 is configured to start the supply of the hydraulic oil pressurized by the pressurizing unit 76 by the timer unit 81 for a predetermined time at a predetermined timing.

<Low-speed injection process>
As shown in FIG. 8, the control device 8 is configured to cut off the connection between the rod side chamber S1 and the pressurizing portion 76 by the first switching valve 279a when the injection of the molten metal by the plunger 6 is started. There is. That is, the control device 8 is configured to perform the control that cannot pressurize the rod side chamber S1 by the pressurizing unit 76 during the low-speed injection process in which the meter-out control is started.

Specifically, the control device 8 cuts off the connection between the rod side chamber S1 and the pressurizing portion 76 by the first switching valve 279a and starts the second switching valve 279b when the injection of the molten metal by the plunger 6 is started. Thus, the control for connecting the rod side chamber S1 and the tank 73 is performed. That is, the control device 8 is configured to control the rod side chamber S1 and the pressurizing unit 76 not to communicate with each other and the rod side chamber S1 and the tank 73 to communicate with each other when the pressure reduction of the rod side chamber S1 is started. ing. The rest of the configuration of the second embodiment is the same as that of the first embodiment.

In the high-speed injection process and the pressure-intensified injection process, the connection between the rod side chamber S1 and the pressurizing portion 76 is cut off by the first switching valve 279a, and the rod side chamber S1 and the tank 73 are connected by the second switching valve 279b. In this state, the same steps as those in the first embodiment are performed, and thus the description thereof will be omitted. Also in the return process, the first switching valve 279a connects the rod-side chamber S1 to the pressurizing unit 76, and the second switching valve 279b disconnects the rod-side chamber S1 from the tank 73. Since the same steps as those in the first embodiment are performed, the description thereof will be omitted.

(Effects of Second Embodiment)
The effects of the second embodiment will be described.

In the second embodiment, as described above, the injection device 207 is provided with the switching valve 79 that switches connection or disconnection between the rod side chamber S1 and the pressurizing portion 76. The switching valve 79 is arranged between the rod side chamber S1 and the pressurizing portion 76. Thereby, the piston 71 can be stably advanced in the meter-out control.

Further, in the second embodiment, as described above, the switching valve 79 includes the first switching valve 279a for switching between connection and disconnection between the rod side chamber S1 and the pressurizing unit 76, and the rod side chamber S1 and the tank 73. A second switching valve 279b for switching between connection and disconnection is provided. The control device 8 is configured to perform control for switching the first switching valve 279a and the second switching valve 279b in synchronization with each other. Accordingly, when a single switching valve is used, the function required for the single switching valve can be divided into the first switching valve 279a and the second switching valve 279b, and thus the switching valve of the injection device 207. It is possible to suppress the complication of the structure. As a result, the piston 71 can be stably advanced in the meter-out control, and the complication of the structure of the switching valve of the injection device 207 can be suppressed. The other effects of the second embodiment are similar to those of the first embodiment.

[Third Embodiment]
Next, the configuration of the injection device 307 according to the third embodiment of the present invention will be described with reference to FIGS. 1 and 9. In the third embodiment, an example in which the rod-side chamber S1 is pressurized by the pressure booster 375 will be described, unlike the first embodiment in which the pressure booster 76 that is separate from the pressure booster 75 is used. In addition, in the third embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

(Injection device)
As shown in FIG. 9, the injection device 307 of the third embodiment includes an accumulator 70 (ACC), a piston 71, a cylinder 72, a tank 73, a position sensor 74, a pressure booster 375, and a pump line 77. And a check valve 78 and a switching valve 79. The switching valve 79 is an example of the "switching unit" in the claims. The pump line 77 is an example of the "hydraulic oil supply source" in the claims. The pressure booster 375 is an example of the “pressurizer” in the claims.

The control device 308 includes a storage unit that stores a control program for controlling the drive of each unit of the die casting machine 301 (see FIG. 1). The control program has an injection processing unit 308a. The control device 308 controls each unit of the injection device 307 by the injection processing unit 308a.

Further, the injection device 307 has a plurality of flow paths that connect each of a plurality of configurations. The plurality of flow passages include a first flow passage 91, a second flow passage 92, a third flow passage 93, a fourth flow passage 94, a fifth flow passage 395, a sixth flow passage 96 and a seventh flow passage 97, respectively. Have The fourth flow path 94 is an example of the "flow path" in the claims.

The first flow passage 91 is a flow passage that connects the accumulator 70 and the cylinder 72. The second flow path 92 is a flow path that branches from the first flow path 91 and connects the accumulator 70 and the pressure booster 375. The third flow path 93 is a flow path that joins the first flow path 91 and connects the pressure booster 375 and the cylinder 72. The fourth flow path 94 is a flow path that connects the pump line 77 and the switching valve 79. The fifth flow path 395 is a flow path that connects the pressure booster 375 and the fourth flow path 94. The sixth flow path 96 is a flow path that connects the switching valve 79 and the cylinder 72. The seventh flow passage 97 is a flow passage that connects the switching valve 79 and the tank 73.

The pressure booster 375 is configured to increase the pressure in the head side chamber S2 by supplying hydraulic oil to the head side chamber S2 before the injection of the molten metal by the plunger 6 is completed. The pressure booster 375 is connected to the accumulator 70 via the first flow passage 91 and the second flow passage 92. The pressure booster 375 is connected to the head-side chamber S2 via the third flow path 93 and the first flow path 91.

The pressure booster 375 of the third embodiment is also provided as the pressurizer 76 of the first embodiment, and is configured to be able to pressurize the rod side chamber S1 before the injection of molten metal by the plunger 6 is started. Has been done. Specifically, the pressure booster 375 is configured to pressurize the rod side chamber S1 before the injection of the molten metal by the plunger 6 is started.

<Pressure process>
As shown in FIG. 9, the control device 8 is configured to perform control for connecting the rod side chamber S1 and the pressurizing portion 76 by the switching valve 79 at a predetermined timing before the injection of the molten metal by the plunger 6 is started. Has been done. That is, the control device 8 is configured to perform the control of pressurizing the rod side chamber S1 by the pressure booster 375 in the pressurizing process started at a predetermined timing.

The low-speed injection process, the high-speed injection process, the pressure boosting injection process, and the return process are the same as those in the first embodiment, and therefore their explanations are omitted. The rest of the configuration of the third embodiment is similar to that of the first embodiment.

(Effect of the third embodiment)
The effects of the third embodiment will be described.

In the third embodiment, as described above, the injection device 307 is provided with the switching valve 79 that switches connection or disconnection between the rod side chamber S1 and the pressurizing unit 76. The switching valve 79 is arranged between the rod side chamber S1 and the pressurizing portion 76. Thereby, the piston 71 can be stably advanced in the meter-out control.

In addition, in the third embodiment, as described above, the pressure booster 375 is also provided as the pressure booster 76 of the first embodiment. The pressure booster 375 is configured to be able to pressurize the rod side chamber S1 when the injection of molten metal by the plunger 6 is started. As a result, it is possible to suppress an increase in the number of parts as compared with the case where the pressure boosting unit and the pressure applying unit are separately provided, and thus it is possible to suppress the configuration of the injection device 307 from becoming complicated. The other effects of the third embodiment are similar to those of the first embodiment.

[Modification]
It should be understood that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and further includes meanings equivalent to the scope of the claims and all modifications within the scope.

For example, in the above-described first and third embodiments, the switching valve 79 (switching portion) has a connection between the rod side chamber S1 and the pressurizing portion 76 (pressure increasing portion 375) and a connection between the rod side chamber S1 and the tank 73. Although the example of the three-way valve that switches the connection between the rod side chamber S1 and the pressurizing unit 76 (pressure increasing unit 375) and the tank 73 is shown, the present invention is not limited to this. In the present invention, the connection between the rod side chamber and the pressurizing unit, the connection between the rod side chamber and the pump line, the connection between the rod side chamber and the tank, the disconnection between the rod side chamber and the pressurizing unit, the tank and the pump line. It may be a four-way valve or the like that switches the four connection states.

Further, in the first and third embodiments, the example in which the switching valve 79 is the hydraulic servo valve (electromagnetic hydraulic switching valve) is shown, but the present invention is not limited to this. In the present invention, the switching valve may be another type of flow control valve such as an electric servo valve.

Further, in the second embodiment, the example in which the first switching valve 279a is a hydraulic servo valve (electromagnetic hydraulic switching valve) is shown, but the present invention is not limited to this. In the present invention, the first switching valve may be an electromagnetic valve having only the function of opening and closing.

Moreover, in the said 1st-3rd embodiment, although the example which comprised the die-casting machine 1 (301) horizontally was shown, this invention is not restricted to this. In the present invention, the die casting machine may be constructed vertically.

Further, in the first to third embodiments, the control device 8 (308, control unit) controls the low speed injection process, the high speed injection process, and the increased pressure injection based on the tip position of the plunger 6 detected by the position sensor 74. Although the example in which the start of the process and the returning process is determined has been shown, the present invention is not limited to this. For example, the control unit may be configured to determine the start of the low speed injection process, the high speed injection process, the pressure boosting injection process, and the return process based on information detected by a sensor other than the position sensor.

Further, in the above-described first and second embodiments, the control device 8 (control unit) shows an example in which the pressing unit 76 is driven by the timer unit 81, but the present invention is not limited to this. In the present invention, the control unit may drive the pressure unit by the injection processing unit without using the timer unit.

Further, in the above-described first embodiment, for convenience of description, the processing operation of the control device 8 (control unit) has been described using the flow-driven flowchart that sequentially performs processing according to the processing flow. Not limited to In the present invention, the processing operation of the control unit may be performed by an event driven type (event driven type) processing that executes processing on an event-by-event basis. In this case, the event driving may be completely performed, or the event driving and the flow driving may be combined.

1 Die casting machine 6 Plunger 7, 207, 307 Injection device 8, 308 Control device (control unit)
71 Piston 72 Cylinder 73 Tank 75, 375 Pressure-increasing part 76 Pressurizing part 77 Pump line (hydraulic oil supply source)
78 Check valve 79 Switching valve (switching part)
94 4th flow path (flow path)
279a First switching valve (switching unit)
279b Second switching valve (switching section)
S Cylinder chamber S1 Rod side chamber S2 Head side chamber

Claims (11)

A piston connected to the plunger,
A cylinder containing the piston, including a cylinder chamber divided into a rod side chamber and a head side chamber by the piston;
A pressurizing unit for pressurizing the rod side chamber before the injection of the molten metal by the plunger is started,
A switching unit that switches connection or disconnection between the rod-side chamber and the pressure unit,
The switching device is an injection device arranged between the rod side chamber and the pressurizing unit. The injection device according to claim 1, further comprising a control unit that controls the switching unit to disconnect the rod side chamber from the pressurizing unit when the injection of the molten metal by the plunger is started. Further comprising a tank for discharging the hydraulic oil in the rod side chamber,
The switching unit is configured to switch connection or disconnection between the rod side chamber and the tank,
When the injection of the molten metal by the plunger is started, the control unit cuts off the connection between the rod side chamber and the pressurizing unit by the switching unit, and switches the rod side chamber and the tank by the switching unit. The injection device according to claim 2, which is configured to perform a connection control. The control unit is configured to perform control for connecting the rod side chamber and the pressurizing unit by the switching unit at a predetermined timing before the injection of molten metal by the plunger is started. Or the injection device according to 3. The control unit connects the rod-side chamber and the pressurizing unit by the switching unit at a predetermined timing before the injection of the molten metal by the plunger is started, and the rod-side chamber is maintained by the pressurizing unit for a predetermined time. The injection device according to claim 4, wherein the injection device is configured to perform control to apply pressure. The switching unit switches the connection between the rod side chamber and the pressurizing unit, the connection between the rod side chamber and the tank, and the disconnection of the connection between the rod side chamber and the pressurizing unit and the tank. The injection device according to claim 3, comprising: The switching unit includes a first switching valve that switches connection and disconnection between the rod-side chamber and the pressurizing unit, and a second switching valve that switches connection and disconnection between the rod-side chamber and the tank. ,
The injection device according to claim 3, wherein the control unit is configured to perform control for switching the first switching valve and the second switching valve in synchronization with each other. Before the injection of the molten metal by the plunger is completed, a pressure increasing unit for increasing the pressure of the head side chamber by supplying hydraulic oil to the head side chamber is further provided.
The pressurizing unit is provided separately from the pressure increasing unit, and is configured to pressurize the rod side chamber before the injection of molten metal by the plunger is started. The injection device according to item 1. Before the injection of the molten metal by the plunger is completed, a pressure increasing unit for increasing the pressure of the head side chamber by supplying hydraulic oil to the head side chamber is further provided.
The pressure increasing unit is also provided as the pressure applying unit, and is configured to pressurize the rod side chamber before the injection of the molten metal by the plunger is started. The injection device according to item 1. A pump line for supplying hydraulic oil to the rod side chamber,
A flow path connecting the switching unit and the pump line,
The injection device according to claim 1, further comprising a check valve arranged upstream of the pump line in the flow path. A cylindrical sleeve having a pouring port through which molten metal is poured by the pouring mechanism,
A plunger for injecting the molten metal poured into the sleeve,
An injection device for moving the plunger within the sleeve,
The injection device is
A piston connected to the plunger,
A cylinder containing the piston, the cylinder including a cylinder chamber in which the internal space is divided into a rod side chamber and a head side chamber by the piston;
A pressurizing unit for pressurizing the rod side chamber before the injection of the molten metal by the plunger is started,
A switching unit that switches connection or disconnection between the rod side chamber and the pressurizing unit;
The die casting machine, wherein the switching unit is arranged between the rod side chamber and the pressurizing unit.

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