JP7294821B2 - Injection unit and die casting machine - Google Patents

Description

TECHNICAL FIELD 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 having a piston connected to a plunger and a cylinder containing the piston.

2. Description of the Related Art Conventionally, an injection device and a die casting machine are known which include a piston connected to a plunger and a cylinder containing the piston (see Patent Document 1, for example).

Patent Document 1 above 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 face on the rod side pressure chamber side of the piston head portion of Patent Document 1 is the same as the area of the rod portion of the piston arranged in the rod side pressure chamber. smaller than area.

The accumulator of Patent Document 1 is configured to supply hydraulic fluid to each of the head-side pressure chamber and the rod-side pressure chamber. The meter-out logic valve of Patent Literature 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 disclosed in Patent Document 1, the pressure of the hydraulic oil in the head-side pressure chamber is applied to the end surface of the head portion of the piston on the side of the head-side pressure chamber, whereby a forward force for advancing the piston is generated. occur. In the head portion of the piston disclosed in Patent Document 1, the pressure of hydraulic fluid in the rod-side pressure chamber is applied to the end face of the piston head portion on the rod-side pressure chamber side, thereby generating a retreating force that causes the piston to retreat.

The injection apparatus of Patent Document 1 is configured to perform meter-out control in which the forward force generated in the hydraulic fluid in the head-side pressure chamber is suppressed by the backward force generated in the hydraulic fluid 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 pressure in the head-side pressure chamber It is comparable to the hydraulic oil pressure. Further, since the area of the rod-side pressure chamber side end surface of the piston head portion is smaller than the area of the head-side pressure chamber side end surface of the piston head portion, the backward force is smaller than the forward force. Therefore, in the injection device of Patent Document 1, when injection of the molten metal by the plunger is started, the advancing force generated on the end surface of the head portion of the piston on the side of the head-side pressure chamber is applied to the pressure chamber on the rod-side side of the head portion of the piston. It is difficult to perform meter-out control that is suppressed by the retreating force generated on the end face. Therefore, in the injection device of Patent Document 1, there is a problem that the piston advances in an uncontrollable state to a position where the advancing force and the retreating force generated in the head portion of the piston are balanced.

JP-A-6-339764

Therefore, although not disclosed in Patent Document 1, it is conceivable that the injection device is provided with a pressurizing section that pressurizes the inside of the rod-side pressure chamber in order to eliminate the above inconvenience. If the pressurizing part is placed between the meter-out logic valve and the tank, it cannot pressurize the rod-side pressure chamber, so it is considered to be placed between the rod-side pressure chamber and the meter-out logic valve be done.

In such an injection device, the forward force and the backward force are caused by the fact that 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 on the head side pressure chamber side of the piston head portion. The difference can be compensated for by pressurizing the rod-side pressure chamber with the pressurizing part.

However, in the above injection apparatus, even if the hydraulic fluid in the rod side pressure chamber is discharged through the meter-out logic valve by meter-out control to reduce the pressure in the rod side pressure chamber, the pressure in the rod side pressure chamber is reduced by the pressurizing section. There is the inconvenience of being pressurized. In other words, in the above injection device, if the pressurizing section 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 during meter-out control. . For this reason, the above injection device has a problem that it becomes difficult to stably advance the piston during meter-out control.

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

In order to achieve the above object, an injection device according to a first aspect of the present invention comprises a piston connected to a plunger, and a cylinder containing the piston and having a cylinder chamber divided into a rod-side chamber and a head-side chamber by the piston. , an accumulator that flows hydraulic oil into the head-side chamber to advance the piston, a pump line that supplies hydraulic oil to the rod-side chamber when the piston is retracted and returned to the return position, and a plunger before injection of molten metal is started. a pressurizing portion that pressurizes the rod-side chamber ; a first flow passage that connects the pressurizing portion and the rod-side chamber; a switching unit for switching; a second flow path branched from the first flow path and connected to the pump line; and a third flow path provided separately from the first flow path and connected to the accumulator and the head-side chamber. , the switching portion is disposed between the rod-side chamber and the pressurizing portion in the first flow path provided separately from the third flow path .

As described above, the injection device according to the first aspect of the present invention is provided with a switching section for switching connection or disconnection between the rod-side chamber and the pressurizing section. And a switching part is arrange|positioned between a rod side chamber and a pressurization part. As a result, when performing meter-out control and reducing the pressure in the rod side chamber by discharging the hydraulic oil in the rod side chamber, the switching portion cuts off the connection between the rod side chamber and the pressurizing portion, thereby It is possible to prevent the rod-side chamber from being pressurized by the pressure portion. Therefore, when performing meter-out control, when the pressure in the rod-side chamber is reduced by discharging hydraulic oil supplied to the rod-side chamber, it is possible to avoid pressurization of the rod-side chamber by the pressurizing portion. . As a result, when the meter-out control is performed, 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 injection of the molten metal can be stabilized. In addition, even when the pressure of the hydraulic fluid in the rod side chamber becomes higher than that of the pressurizing portion, the connection between the rod side chamber and the pressurizing portion is cut off by the switching portion, so that the hydraulic fluid in the rod side chamber does not flow to the pressurizing portion. Backflow can be prevented.

The injection apparatus according to the first aspect preferably further includes a control section that performs control such that the switching section disconnects the rod side chamber and the pressurizing section when injection of the molten metal by the plunger is started. According to this configuration, when injection of molten metal by the plunger is performed by meter-out control, it is possible to prevent the rod-side chamber from being pressurized by the pressurizing section from the start of injection of molten metal by the plunger. 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 portion while the molten metal is being injected by the plunger. As a result, the injection of the molten metal can be stabilized by stably moving the piston forward while the plunger is injecting the molten metal.

In this case, preferably, a tank for discharging the hydraulic oil in the rod-side chamber is further provided, the switching unit is configured to be capable of switching between connection and disconnection of the rod-side chamber and the tank, and the control unit includes a plunger for injection of molten metal. is started, the switching portion cuts off the connection between the rod side chamber and the pressurizing portion, and the switching portion controls the connection between the rod side chamber and the tank. With this configuration, while the pressure in the rod side chamber is adjusted by discharging hydraulic oil in the rod side chamber to the tank and meter-out control is performed to move the piston forward, the pressure between the rod side chamber and the pressurizing portion is maintained. By interrupting the connection by the switching portion, it is possible to ensure that the pressurizing portion does not pressurize the rod-side chamber. As a result, it is possible to prevent the pressure of the hydraulic fluid in the rod side chamber from becoming unstable due to the pressurizing portion while the meter-out control is being performed. In addition, unlike the meter-in control that advances the piston by controlling only the forward force of the hydraulic oil in the head side chamber, the meter-out control uses the forward force generated in the hydraulic oil in the head side chamber to control the hydraulic oil in the rod side. can be suppressed by the backward force generated in Therefore, unlike the meter-in control in which the piston advances (protrudes out) in an uncontrollable state, the meter-out control does not require precise control of the forward force unless the forward force is precisely controlled. As a result, it is not necessary to provide a plurality of valves necessary for precisely adjusting the advancing force on the upstream side of the head side chamber of the cylinder.

In the injection apparatus including the control unit, preferably, the control unit is configured to perform control to connect the rod-side chamber and the pressurizing unit by the switching unit at a predetermined timing before injection of the molten metal by the plunger is started. It is According to this structure, the pressure of the hydraulic oil in the rod side chamber can be pressurized by the pressurizing portion 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 advancing force generated on the end surface of the piston head portion on the head side chamber side due to the ratio of the area of the end surface on the head side chamber side of the piston head portion to the area of the end surface on the rod side chamber side of the head portion of the piston and the piston The pressurizing portion can compensate for the difference from the retreating force generated on the end face of the rod-side chamber side of the head portion. As a result, when the meter-out control is performed, it is possible to prevent the piston from advancing uncontrollably 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 injection of the molten metal by the plunger is started, and presses the rod-side chamber by the pressurizing unit for a predetermined time. It is configured to perform pressure control. With this configuration, the pressure of the hydraulic fluid in the rod-side chamber can be reliably reached to a desired pressure by the pressurization of the pressurizing portion. The pressurizing portion can reliably compensate for the difference from the retreating force generated on the rod-side chamber side end surface of the head portion of the piston. Further, since the pressurization by the pressurizing portion is stopped after the predetermined time has elapsed, the pressure in the rod-side chamber becomes unstable due to the pressurizing portion even if the connection between the rod-side chamber and the pressurizing portion is not cut off by the switching portion. can be suppressed.

In the injection apparatus including the switching section and the tank, preferably, the switching section includes a connection between the rod side chamber and the pressurizing section, a connection between the rod side chamber and the tank, and a connection between the rod side chamber and the pressurizing section and the tank. It includes a switching valve that switches between shutting off the With this configuration, 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, thereby suppressing an increase in the number of parts of the injection device. In addition, it is possible to prevent the configuration of the injection device from becoming complicated.

In the injection apparatus provided with the switching valve and the tank, preferably, the switching section includes a first switching valve for switching connection and disconnection between the rod side chamber and the pressurizing section, and connection and connection between the rod side chamber and the tank. and a second switching valve for switching shut-off, and the control unit is configured to perform control for synchronously switching the first switching valve and the second switching valve. With this configuration, 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. It is possible to suppress complication of the structure of the valve. As a result, the piston can be stably advanced in the meter-out control, and complication of the structure of the switching valve of the injection device can be suppressed.

The injection apparatus according to the first aspect preferably further comprises a pressure increasing section for increasing 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 part is provided separately from the pressure increasing part, and is configured to pressurize the rod side chamber before injection of the molten metal by the plunger is started. With this configuration, compared to the case where the pressure increasing section and the switching section are connected to pressurize the rod side chamber by the pressure increasing section,
Since the pressurizing section can be arranged near the switching section, the pressurizing section and the switching section can be easily connected.

The injection device according to the first aspect preferably further includes a check valve arranged upstream of the branching of the second flow path to the first flow path and downstream of the pump line.

A die casting machine according to a second aspect of the present invention comprises a cylindrical sleeve having a pouring port into which molten metal is poured by a pouring mechanism, a plunger for injecting 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 and having a cylinder chamber divided by the piston into a rod-side chamber and a head-side chamber, and a head-side chamber . An accumulator that flows hydraulic oil into the piston to advance the piston, a pump line that supplies hydraulic oil to the rod side chamber when the piston is retracted and returned to the return position, and a rod before the injection of molten metal by the plunger is started. A pressurizing part that pressurizes the side chamber, a first flow path that connects the pressurizing part and the rod side chamber, and a switching part that is arranged in the first flow path and switches connection or disconnection of the connection between the rod side chamber and the pressurizing part. and a second flow path branched from the first flow path and connected to the pump line, and a third flow path provided separately from the first flow path and connected to the accumulator and the head-side chamber, and a switching portion is arranged between the rod-side chamber and the pressurizing portion in the first channel provided separately from the third channel .

In the die casting machine according to the second aspect of the present invention, as described above, a switching section is provided for switching connection or disconnection between the rod-side chamber and the pressurizing section. The switching section is arranged between the rod-side chamber and the pressurizing section. As a result, when meter-out control is performed, even if the pressure in the rod side chamber is reduced by discharging the hydraulic oil in the rod side chamber, the connection between the rod side chamber and the pressurizing portion is cut off by the switching portion. It is possible to prevent the rod-side chamber from being pressurized by the pressure portion. Therefore, when performing meter-out control, even if the pressure in the rod side chamber is reduced by discharging the hydraulic fluid supplied to the rod side chamber, it is possible to avoid pressurizing the rod side chamber by the pressurizing portion. . That is, when performing meter-out control, it is possible to avoid unstable pressure changes in the rod-side chamber. As a result, it is possible to obtain a die casting machine capable of stably advancing the piston under meter-out control.

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

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed typically the whole die-casting machine structure by 1st Embodiment. FIG. 4 is a diagram schematically showing a state of a pressurizing process in the injection device according to the first embodiment; FIG. 4 is a diagram schematically showing states of a low-speed injection process and a high-speed injection process in the injection apparatus according to the first embodiment; FIG. 4 is a diagram schematically showing a state of a pressure boosting injection process in the injection apparatus according to the first embodiment; FIG. 4 is a diagram schematically showing the state of the return process in the injection device according to the first embodiment; 4 is a flowchart showing injection processing of the control device in the injection device according to the first embodiment; FIG. 10 is a diagram schematically showing a state of a pressurizing process in the injection device according to the second embodiment; FIG. 10 is a diagram schematically showing the state of the low-speed injection process in the injection device according to the second embodiment; FIG. 10 is a diagram schematically showing a state of a pressurizing process in the injection device according to the third embodiment;

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

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

(Configuration of die casting machine)
As shown in FIG. 1, the die casting machine 1 is a horizontal machine in which a movable die 21 is horizontally moved. Further, the die casting machine 1 is a machine of a cold chamber system, and a molten metal (liquid metal material) to produce a die-cast product (molded product).

A 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 . Note that the control device 8 is an example of a "control unit" in the scope of claims.

Here, in the following description, the up-down direction is the Z direction, and the extending direction of the plunger 6 is the X direction among the horizontal directions. Also, of the X directions, the moving direction of the plunger 6 when injecting the molten metal is defined as the X1 direction, and the opposite direction of the X1 direction is defined as 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 mold 22 is fixed to a fixed die plate 23 . The movable mold 21 is attached to a movable die plate 24 so as to be movable in a direction (X direction) to contact or separate from the fixed mold 22 . The cavity C is formed by bringing the movable mold 21 into contact with the fixed mold 22 .

The sleeve 3 accommodates the plunger 6 so as to be movable in the X direction and is configured to be capable of pouring molten metal.

Specifically, the sleeve 3 includes a pouring port 31 and a molten metal passage 32 . The sleeve 3 has a cylindrical shape. The sleeve 3 extends in the X direction. The pouring port 31 is provided for pouring molten metal into the molten metal passage 32 by the pouring mechanism 4 . The pouring port 31 penetrates the Z1 direction side portion of the sleeve 3 in the Z direction. The molten metal passage 32 is a through hole penetrating 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 a liquid metal material (molten metal) from a holding furnace (not shown) and supply (pouring) it to the sleeve 3 .

Specifically, the pouring mechanism 4 includes a ladle 41 and an arm 42 . The ladle 41 is configured to scoop 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 molten metal into the sleeve 3 .

The lid mechanism 5 is configured to close the pouring port 31 after the molten metal is poured 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 along the shape of the pouring port 31 when viewed from the Z1 direction. The lid portion 51 is arranged at the tip portion 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 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 contacts 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 bar 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 molten metal into the cavity C by moving the plunger 6 . That is, the injection device 7 is configured to reciprocate the plunger 6 within the sleeve 3 in the X direction. Specifically, as shown in FIG. 2, the injection device 7 includes an accumulator 70 (ACC), a piston 71, a cylinder 72, a tank 73, a position sensor 74, a pressure booster 75, an 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 a "switching part" in the claims. The pump line 77 is an example of a "hydraulic oil supply source" in the claims.

In addition, the injection device 7 has a plurality of flow paths connecting each of the plurality of components. The plurality of flow paths are respectively 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. have. In addition, the fourth flow path 94 is an example of a "flow path" in the scope of claims.

The first flow path 91 is a flow path that connects the accumulator 70 and the cylinder 72 . The second flow path 92 is a flow path that branches off from the first flow path 91 and connects the accumulator 70 and the pressure increasing section 75 . The third flow path 93 is a flow path that joins the first flow path 91 and connects the pressure increasing portion 75 and the cylinder 72 . A 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 off from the fourth flow path 94 and connects the pressurizing portion 76 and the switching valve 79 . A sixth flow path 96 is a flow path that connects the switching valve 79 and the cylinder 72 . A seventh flow path 97 is a flow path that connects the switching valve 79 and the tank 73 .

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

The piston 71 is configured to reciprocate within 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 cylindrical shape. In the Z direction, the length of the head portion 71a is longer than that of the rod portion 71b. The X1-direction-side end of the head portion 71a is connected to the X2-direction-side end of the rod portion 71b. The rod portion 71b has a cylindrical shape. The end of the rod portion 71b on the X2 direction side is connected to the central portion of the head portion 71a in the Z1 direction.

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

Piston 71 is connected to 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. Thereby, the plunger 6 is configured to be movable in conjunction with the movement of the piston 71 in the X direction.

The cylinder 72 is configured to allow the flow of hydraulic fluid for moving the piston 71 in the X1 direction and hydraulic fluid for moving the piston 71 in the X2 direction. Specifically, the cylinder 72 incorporates the piston 71 and has a cylinder chamber S divided by the piston 71 into a rod side chamber S1 and a head side chamber S2. The cylinder 72 also has a first opening 72a and a second opening 72b.

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

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

The volume of the head-side chamber S2 increases as the piston 71 moves (advances) in the X1 direction. The volume of the head-side chamber S2 decreases as the piston 71 moves (retracts) in the X2 direction.

The rod-side chamber S1 is a space in the cylinder chamber S on the X1 direction side of the head portion 71a of the piston 71 . Hydraulic oil from the switching valve 79 flows into the rod side chamber S1. As a result, the head portion 71a of the piston 71 generates a retreating force that moves the piston 71 in the X2 direction. The retraction force is a force that causes the piston to retract (pushes in the X2 direction) when the pressure of the hydraulic fluid 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 decreases as the piston 71 moves (advances) 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 72 a connects the accumulator 70 or the pressure increasing portion 75 and the head-side chamber S<b>2 of the cylinder 72 . Hydraulic fluid from the accumulator 70 or hydraulic fluid from the pressure increasing portion 75 flows into the head-side chamber S2 through the first opening 72a. 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 penetrating the cylinder 72 in the X direction. The first opening 72 a is connected to the downstream end of the first flow path 91 .

The second opening 72 b connects the rod side chamber S 1 of the cylinder 72 and the switching valve 79 . Through the second opening 72b, hydraulic fluid in the rod side chamber S1 flows out to the switching valve 79, or hydraulic fluid 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 penetrating the cylinder 72 in the Z direction. The second opening 72 b is connected to the downstream end of the sixth flow path 96 .

The cylinder 72 is configured such that the rod portion 71b of the piston 71 arranged inside the cylinder 72 and the plunger 6 arranged outside the cylinder 72 can be connected. 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. Thus, 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 hydraulic fluid discharged from the rod-side chamber S<b>1 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 amount of protrusion of the rod portion 71 b 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 amount of protrusion of the rod portion 71b. The position sensor 74 is electrically connected to the controller 8 .

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

<Pressure part>
The pressurizing part 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 part 76 is provided separately from the pressure increasing part 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 manner, the pressurizing unit 76 pressurizes the hydraulic oil in the rod side chamber S1 in order to prevent the piston 71 from jumping out in the X1 direction in an uncontrollable state when meter-out control is started. is configured to increase the

Specifically, the pressurizing section 76 has a pressurizing piston 76a and a pressurizing cylinder 76b. The pressurizing piston 76a is configured to reciprocate in the X direction within the pressurizing cylinder 76b. 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 pressurized by the pressurizing piston 76a to the rod side chamber S1. The transmission port 173 is a through hole penetrating the pressurizing cylinder 76b in the X direction.

The pressure of the hydraulic fluid in the rod-side chamber S1 increases by moving (advancing) the pressurizing piston 76a in the X1 direction. The pressure of the hydraulic fluid 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 hydraulic oil supplied from a hydraulic source (not shown). The pressurizing piston 76a is moved (retracted) in the X2 direction by hydraulic fluid supplied from a hydraulic source (not shown).

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

<Pump line>
The pump line 77 is configured to supply hydraulic fluid to the cylinder 72 for moving the piston 71 in the X2 direction. That is, the pump line 77 is a pump that pumps up hydraulic oil from the tank 73 . The pump line 77 supplies hydraulic fluid to the rod side chamber S<b>1 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 fluid pressurized by the pressurizing portion 76 from flowing into the pump line 77 when the pressurizing portion 76 pressurizes. Specifically, the check valve 78 is a check valve. The check valve 78 is arranged upstream 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 portion 76 . Further, the switching valve 79 is configured to be able to switch between connection and disconnection between the rod-side chamber S1 and the tank 73 . That is, the switching valve 79 switches connection between the rod side chamber S1 and the pressurizing unit 76, connection between the rod side chamber S1 and the tank 73, and 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 portion 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 S<b>1 and the tank 73 and switches to the second connection state in which the connection between the rod side chamber S<b>1 and the pressurizing section 76 is interrupted. The switching valve 79 cuts off the connection between the rod side chamber S1 and the pressurizing portion 76 and switches to the third connection state in which the connection between the rod side chamber S1 and the tank 73 is cut off. Thus, the rod side chamber S1 and the pressurizing portion 76 are blocked 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 functions as a flow rate 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 functions as an opening/closing valve that disconnects 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 cut off when the pressure of the hydraulic fluid in the rod side chamber S1 is reduced. Specifically, the switching valve 79 is arranged between the rod-side chamber S<b>1 and the pressurizing portion 76 . That is, the switching valve 79 is disposed downstream of the pressurizing portion 76 and upstream of the rod side chamber S1 in the flow of hydraulic oil flowing from the pressurizing portion 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 control device 8 is configured to control 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 storage units such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

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

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

The injection processing section 8a has meter-out control and pressurization control for controlling each section of the injection device 7 . The meter-out control is a control for suppressing the advancing force generated on the end surface of the head portion 71a of the piston 71 on the side of the head side chamber S2 by the backward force generated on the end surface of the head portion 71a of the piston 71 on the side of the rod side chamber S1. Pressurization control pressurizes the rod-side chamber S1 with the pressurizing unit 76 before the meter-out control is started, so that when the meter-out control is started, the forward force generated on the end surface of the head portion 71a of the piston 71 on the side of the head-side chamber S2 is increased. This control compensates for the difference from the retreating force generated on the end face of the head portion 71a of the piston 71 on the side of the rod side chamber S1.

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 addition, for a predetermined time, the pressurization of the rod side chamber S1 by the pressurizing unit 76 causes the backward force generated in the hydraulic oil in the rod side chamber S1 to match the forward force generated in the hydraulic oil in the head side chamber S2. is the time to hold the hydraulic oil pressure. Also, 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 meter-out control and pressurization control using a switching valve 79 to control the movement of the piston 71 and the plunger 6 interlocking with the piston 71. It is

<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 section 76 with the switching valve 79 at a predetermined timing before injection of the molten metal by the plunger 6 is started. It is In other words, the control device 8 is configured to perform control to pressurize the rod-side chamber S1 by the pressurizing section 76 in the pressurizing process started at a predetermined timing.

Specifically, the control device 8 connects the rod-side chamber S1 and the pressure unit 76 with the switching valve 79 at a predetermined timing before the injection of the molten metal by the plunger 6 is started, and causes the pressure unit 76 to It is configured to perform control to pressurize the side chamber S1 for a predetermined time.

Here, the control device 8 is configured to disconnect the rod-side chamber S1 and the tank 73 and connect the rod-side chamber S1 and the pressurizing portion 76 with the switching valve 79 at a predetermined timing. Further, the control device 8 is configured so that the timer section 81 starts pressurization for a predetermined time by the pressurizing section 76 at a predetermined timing. At this time, the pressurizing portion 76 and the rod-side chamber S1 are communicated with each other. As a result, the pressure of the hydraulic fluid in the rod-side chamber S1 is increased by the pressurizing portion 76 . The tank 73 and the rod-side chamber S1 are not communicated with each other. As a result, hydraulic fluid pressurized by the pressurizing portion 76 is not discharged into the tank 73 .

The control device 8 is configured to obtain the predetermined timing by calculating back from the start time of injection of the molten metal by the plunger 6 . Here, the predetermined timing is the time from the end of the return process to the start of the low speed injection process. It should be noted that the predetermined timing is preferably closer to the starting point of the low-speed injection process than to the middle point between the end of the return process and the starting point of the low-speed injection process. Here, the time point at which injection of the molten metal by the plunger 6 is started is the time point at which the low-speed injection process (see FIG. 3) of the injection process is started.

The length of the predetermined time is set according to 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 of injection of the molten metal by the plunger 6, or it may be longer or shorter. It is preferable that the length of the predetermined time is around the time from the predetermined timing to the start point 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 is configured such that the switching valve 79 cuts off the connection between the rod side chamber S1 and the pressurizing portion 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 to avoid pressurization of the rod-side chamber S1 by the pressurizing section 76 during the low-speed injection process in which meter-out control is started.

Specifically, when the injection of the molten metal by the plunger 6 is started, the control device 8 uses the switching valve 79 to cut off the connection between the rod side chamber S1 and the pressurizing portion 76, and also causes the switching valve 79 to open the rod side chamber S1. and the tank 73 are connected. That is, the control device 8 is configured to perform control to prevent communication between the rod side chamber S1 and the pressurizing section 76 and to communicate between the rod side chamber S1 and the tank 73 when pressure reduction of the rod side chamber S1 is started. ing. Here, the rod-side chamber S1 is not pressurized by the pressurizing portion 76 because the pressurizing portion 76 and the rod-side chamber S1 are not communicated with each other. The tank 73 and the rod side chamber S1 are in communication. As a result, the hydraulic oil in the rod side chamber S<b>1 is discharged to the tank 73 .

Here, in order to perform meter-out control, the control device 8 controls the amount of hydraulic oil discharged from the rod-side chamber S1 to the tank 73 in a state in which the connection between the pressurizing portion 76 and the rod-side chamber S1 is cut off by the switching valve 79. configured to control. That is, in the low-speed injection process, the control device 8 adjusts the retreating 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 portion 76, thereby causing the piston 71 to move. is configured to control the forward movement of the Here, the retreating force generated on the end surface of the rod side chamber S1 side of the head portion 71a of the piston 71 is adjusted by discharging hydraulic oil from the rod side chamber S1 to the tank 73 to change the pressure in the rod side chamber S1. .

<High-speed injection process>
As shown in FIG. 3, similar to the low-speed injection process, the control device 8 controls the switching valve 79 to cut off the connection between the pressurizing part 76 and the rod-side chamber S1 during the high-speed injection process in which 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 and the pressurizing portion 76. is configured to perform control to move the piston 71 forward.

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

<Pressurization injection process>
As shown in FIG. 4, similarly to the low-speed injection process, the controller 8 shuts off the connection between the pressurizing part 76 and the rod-side chamber S1 by means of the switching valve 79 during the pressure-increasing injection process in which meter-out control is performed. configured to control. That is, the control device 8 increases 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 and the pressurizing portion 76 in the pressure increasing injection process. It is configured to be adjusted and configured to control the advancement of the piston 71 .

Here, the hydraulic fluid supplied to the head-side chamber S2 is the hydraulic fluid supplied from the pressure intensifying section 75 . The pressure of hydraulic fluid supplied from the pressure intensifier 75 is higher than the pressure of hydraulic fluid supplied from the accumulator 70 . The control device 8 is also configured to determine the start of the pressure boost injection process based on the tip position of the plunger 6 indirectly detected by the position sensor 74 .

<Recovery process>
As shown in FIG. 5, the control device 8 is configured to perform control to connect the pump line 77 and the rod side chamber S1 by the switching valve 79 during the return process. That is, in the return process, the control device 8 supplies hydraulic oil in the pump line 77 to the rod-side chamber S1 without allowing the rod-side chamber S1 and the tank 73 to communicate with each other, thereby causing the piston 71 to retreat and return to the return position. 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 indirectly detected by the position sensor 74 .

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

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

In step S1, the controller 8 determines whether or not it is a predetermined timing. That is, it is determined whether or not to start pressurizing the rod side chamber S1. If it is the predetermined timing, the process proceeds to step S2, and if it is not the predetermined timing, the step S1 is repeated. In step S<b>2 , the control device 8 pressurizes the rod side chamber S<b>1 by the pressurizing section 76 . That is, the timer unit 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 side of the head side chamber S2 and the backward force on the end surface of the head portion 71a of the piston 71 on the side of the rod side chamber S1 are balanced.

In step S3, the controller 8 determines whether or not a predetermined time has passed. If the predetermined time has passed, the process proceeds to step S4, and if the predetermined time has not passed, step S3 is repeated.

Steps S4 and S5 are steps for performing a low-speed injection process in which the plunger 6 is moved at a low speed to inject molten metal.

In step S<b>4 , the control device 8 cuts off the pressurization by the pressurizing section 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 without communicating the rod side chamber S1 and the pressurizing portion 76 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 meter-out control.

Steps S6 and S7 are steps for performing a high-speed injection process in which the plunger 6 is moved at high speed to inject molten metal.

In step S6, the controller 8 determines whether or not the high-speed injection start position is reached. 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 meter-out control.

Steps S8 to S10 are steps for performing a pressurization injection process in which the plunger 6 injects the molten metal while the head-side chamber S2 is pressurized by the pressurization unit 75 .

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

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

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

In step S11, the control device 8 causes the piston 71 to retreat. That is, the plunger 6 interlocking with the piston 71 retreats by supplying hydraulic oil from the pump line 77 to the rod-side chamber S1 to cause the piston 71 to retreat. In step S12, the control device 8 determines whether or not it is at the return position. When it is at the return position, the process returns to step S1, and when it is not at the return position, step S12 is repeated. At this time, the pressure of the hydraulic fluid in the rod side chamber S1 becomes the pressure of the hydraulic fluid in the pump line 77 .

(Effect of the first embodiment)
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 for switching connection or disconnection between the rod-side chamber S1 and the pressurizing portion 76 . A switching valve 79 is arranged between the rod-side chamber S1 and the pressurizing portion 76 . As a result, when meter-out control is performed and the hydraulic fluid in the rod side chamber S1 is discharged to reduce the pressure in the rod side chamber S1, the switching valve 79 cuts off the connection between the rod side chamber S1 and the pressurizing portion 76. By doing so, it is possible to prevent the rod-side chamber S1 from being pressurized by the pressurizing part 76 . Therefore, when the meter-out control is performed, if the pressure in the rod side chamber S1 is reduced by discharging the hydraulic oil supplied to the rod side chamber S1, the pressure unit 76 pressurizes the rod side chamber S1. can be avoided. As a result, when the meter-out control is performed, 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. Further, since the plunger 6 can be stably advanced by stably advancing the piston 71 in the meter-out control, injection of the molten metal can be stabilized. Further, even when the pressure of the hydraulic fluid in the rod side chamber S1 becomes higher than that of the pressurizing portion 76, the switching valve 79 cuts off the connection between the rod side chamber S1 and the pressurizing portion 76, thereby reducing the pressure of the hydraulic fluid in the rod side chamber S1. Backflow to the pressurizing portion 76 due to the pressure can be prevented.

Further, in the first embodiment, as described above, when the plunger 6 starts to inject the molten metal into the injection device 7, the switching valve 79 is controlled to cut off the connection between the rod side chamber S1 and the pressurizing portion 76. A control device 8 is provided for performing As a result, when injection of molten metal is performed by the plunger 6 under meter-out control, it is possible to prevent the rod side chamber S1 from being pressurized by the pressurizing portion 76 from the start of injection of molten metal by the plunger 6 . Therefore, 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 plunger 6 is injecting the molten metal. As a result, the injection of the molten metal can be stabilized by stably moving the piston 71 forward while the plunger 6 is injecting the molten metal.

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 is operated by the switching valve 79 to cut off the connection between the rod side chamber S1 and the pressurizing portion 76, and to switch the rod side chamber S1 and the tank 73 by the switching valve 79. Configure to control the connection. As a result, the connection between the rod side chamber S1 and the pressurizing portion 76 is cut off by the switching valve 79 while the meter-out control is performed, so that the rod side chamber S1 is reliably prevented from being pressurized by the pressurizing portion 76. be able to. As a result, it is possible to prevent the pressure of the hydraulic fluid 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 meter-in control that advances the piston 71 by controlling only the advancing force of the hydraulic oil in the head side chamber S2, in the meter-out control, the advancing force generated in the hydraulic oil in the head side chamber S2 is controlled by the rod side chamber S1. It can be suppressed by the backward force generated in the hydraulic oil inside. Therefore, unlike the meter-in control in which the piston 71 advances (protrudes) in an uncontrollable state, the meter-out control does not require precise control of the advancing force unless the advancing force is precisely controlled. As a result, it is not necessary to provide a plurality of valves necessary for precisely adjusting the advancing force on the upstream side of the head-side chamber S2 of the cylinder 72, so that an increase in the number of parts of the injection device 7 can be suppressed. .

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 injection of the molten metal by the plunger 6 is started. Configure to control. Thereby, the pressure of the hydraulic fluid in the rod side chamber S1 can be pressurized by the pressurizing portion 76 at a predetermined timing. Here, in the Z direction, the area of the end face of the head portion 71a of the piston 71 on the rod side chamber S1 side is larger than the area of the end face of the head portion 71a of the piston 71 on the head side chamber S2 side by the rod portion 71b of the piston 71. is also small. Therefore, it occurs at the end surface of the head portion 71a of the piston 71 on the head side chamber S2 side due to the ratio between the area of the head portion 71a of the piston 71 on the head side chamber S2 side and the area of the head portion 71a of the piston 71 on the rod side chamber S1 side. The pressurizing portion 76 can compensate for the difference between the advancing force and the retreating force generated on the end surface of the head portion 71a of the piston 71 on the rod side chamber S1 side. As a result, when the meter-out control is performed, it is possible to prevent the piston 71 from advancing uncontrollably 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 injection of the molten metal by the plunger 6 is started. In addition, the pressurizing unit 76 is configured to perform control to pressurize the rod side chamber S1 for a predetermined period of time. As a result, the pressure of the hydraulic fluid in the rod-side chamber S1 can be reliably reached to a desired pressure by the pressurization of the pressurizing portion 76, so that the forward force generated on the end surface of the head portion 71a of the piston 71 on the side of the head-side chamber S2. and the retreating force generated on the end face of the head portion 71a of the piston 71 on the rod side chamber S1 side can be reliably compensated for by the pressurizing portion . Further, since the pressurization by the pressurizing portion 76 is stopped after the predetermined time has elapsed, even if the connection between the rod side chamber S1 and the pressurizing portion 76 is not cut off by the switching valve 79, the pressure in the rod side chamber S1 is maintained at the pressurizing portion. Instability due to 76 can be suppressed.

Further, in the first embodiment, as described above, the switching valve 79 is connected between the rod side chamber S1 and the pressurizing portion 76, between the rod side chamber S1 and the tank 73, and between the rod side chamber S1 and the pressurizing portion 76. and disconnection of the connection with the tank 73 are switched. 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 reduced. In addition, it is possible to prevent the configuration of the injection device 7 from becoming complicated.

Further, in the first embodiment, the pressurizing section 76 is provided separately from the pressure increasing section 75 as described above. The pressurizing part 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 portion 76 can be arranged closer to the switching valve 79 than when the pressure increasing portion 75 and the switching valve 79 are connected to pressurize the rod side chamber S1 by the pressure increasing portion 75. Therefore, the pressurizing portion 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 upstream of the pump line 77 in the fourth flow path 94 . As a result, it is possible to prevent the hydraulic fluid pressurized by the pressurizing portion 76 from flowing into the pump line 77 via the fourth flow path 94, so that the hydraulic fluid is reliably supplied from the pressurizing portion 76 to the rod-side chamber S1. can be supplied to

[Second embodiment]
Next, the configuration of an injection device 207 according to a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIG. In the second embodiment, an example using a first switching valve 279a and a second switching valve 279b, which are two-way valves, will be described, unlike the first embodiment using the switching valve 79, which is a three-way valve. In addition, in 2nd Embodiment, the same code|symbol is attached|subjected regarding the structure similar to 1st Embodiment, and description is abbreviate|omitted.

(Injection device)
As shown in FIG. 7, the injection device 207 of the second embodiment includes an accumulator 70 (ACC), a piston 71, a cylinder 72, a tank 73, a position sensor 74, a pressure booster 75, and a pressure booster. 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 each an example of a "switching part" in the claims. The pump line 77 is an example of a "hydraulic oil supply source" in the claims.

Also, the injection device 207 has a plurality of flow paths connecting each of the plurality of configurations. The plurality of flow paths are respectively a first flow path 91, a second flow path 92, a third flow path 93, a fourth flow path 294, a fifth flow path 295, a sixth flow path 296, a seventh flow path 297 and It has an eighth channel 298 . It should be noted that the fourth flow path 294 is an example of a "flow path" in the scope of claims.

The first flow path 91 is a flow path that connects the accumulator 70 and the cylinder 72 . The second flow path 92 is a flow path that branches off from the first flow path 91 and connects the accumulator 70 and the pressure increasing section 75 . The third flow path 93 is a flow path that joins the first flow path 91 and connects the pressure increasing portion 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 off from the fourth flow path 294 and connects the pressurizing portion 76 and the switching valve 79 . The sixth flow path 296 is a flow path that connects the first switching valve 279 a and the seventh flow path 297 . The seventh flow path 297 is a flow path that connects the second switching valve 279 b and the cylinder 72 . The eighth flow path 298 is a flow path that connects the second switching valve 279 b 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 portion . 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. Each of the first switching valve 279a and the second switching valve 279b is a hydraulic servo valve (electromagnetic hydraulic switching valve).

(Control device)
The control device 8 of the second embodiment is configured to synchronously switch the first switching valve 279a and the second switching valve 279b. That is, the control device 8 is configured to perform control to connect the rod-side chamber S1 and the pressurizing section 76 with the first switching valve 279a and to cut off the connection between the rod-side chamber S1 and the tank 73 with the second switching valve 279b. It is Further, 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 performs control to connect the rod side chamber S1 and the tank 73 by the second switching valve 279b. 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 section 76 at a predetermined timing before the injection of the molten metal by the plunger 6 is started. is configured to

Specifically, at a predetermined timing, the control device 8 disconnects the rod side chamber S1 and the tank 73 by the second switching valve 279b, and disconnects the rod side chamber S1 and the pressurizing section 76 by the first switching valve 279a. configured to connect. Further, the control device 8 is configured to start supplying the hydraulic oil pressurized by the pressurizing section 76 for a predetermined time by the timer section 81 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 control so that the pressurizing section 76 cannot pressurize the rod side chamber S1 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 cuts off the connection between the rod side chamber S1 and the pressurizing portion 76 by the first switching valve 279a, and also closes the second switching valve 279b. is configured to perform control to connect the rod-side chamber S1 and the tank 73 by. That is, the control device 8 is configured to perform control to prevent communication between the rod side chamber S1 and the pressurizing section 76 and to communicate between the rod side chamber S1 and the tank 73 when pressure reduction of the rod side chamber S1 is started. ing. Other configurations of the second embodiment are the same as those of the first embodiment.

In the high-speed injection process and the increased pressure injection process, the connection between the rod side chamber S1 and the pressurizing unit 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 in the first embodiment are performed, so the description is omitted. Also, in the return process, the first switching valve 279a connects the rod-side chamber S1 and 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 in the first embodiment are performed, description thereof is omitted.

(Effect of Second Embodiment)
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 for switching connection or disconnection between the rod-side chamber S1 and the pressurizing section 76 . A switching valve 79 is arranged between the rod-side chamber S<b>1 and the pressurizing portion 76 . Thereby, the piston 71 can be stably advanced in the meter-out control.

In addition, in the second embodiment, as described above, the switching valve 79 includes the first switching valve 279a that switches between connection and disconnection between the rod side chamber S1 and the pressurizing portion 76, and the connection between 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 synchronously switching the first switching valve 279a and the second switching valve 279b. Accordingly, when a single switching valve is used, the functions required for the single switching valve can be divided into the first switching valve 279a and the second switching valve 279b. complication of the structure can be suppressed. As a result, the piston 71 can be stably advanced in the meter-out control, and complication of the structure of the switching valve of the injection device 207 can be suppressed. Other effects of the second embodiment are the same as those of the first embodiment.

[Third Embodiment]
Next, the configuration of an injection device 307 according to a third embodiment of the present invention will be described with reference to FIGS. 1 and 9. FIG. In the third embodiment, unlike the above-described first embodiment in which a pressurizing section 76 separate from the pressure increasing section 75 is used, an example in which the pressure increasing section 375 pressurizes the rod side chamber S1 will be described. In addition, in 3rd Embodiment, the same code|symbol is attached|subjected regarding the structure similar to 1st Embodiment, and description is abbreviate|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, a pump line 77 , a check valve 78 and a switching valve 79 . The switching valve 79 is an example of a "switching part" in the claims. The pump line 77 is an example of a "hydraulic oil supply source" in the claims. The pressure booster 375 is an example of a "pressurizer" in the scope of claims.

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

Further, the injection device 307 has a plurality of flow paths connecting each of the plurality of configurations. The plurality of flow paths are respectively a first flow path 91, a second flow path 92, a third flow path 93, a fourth flow path 94, a fifth flow path 395, a sixth flow path 96 and a seventh flow path 97. have. In addition, the fourth flow path 94 is an example of a "flow path" in the scope of claims.

The first flow path 91 is a flow path that connects the accumulator 70 and the cylinder 72 . The second flow path 92 is a flow path that branches off from the first flow path 91 and connects the accumulator 70 and the pressure increasing section 375 . The third flow path 93 is a flow path that joins the first flow path 91 and connects the pressure increasing portion 375 and the cylinder 72 . A 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 increasing portion 375 and the fourth flow path 94 . A sixth flow path 96 is a flow path that connects the switching valve 79 and the cylinder 72 . A seventh flow path 97 is a flow path that connects the switching valve 79 and the tank 73 .

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

Further, the pressure increasing portion 375 of the third embodiment is provided also as the pressure increasing portion 76 of the first embodiment, and is configured to be able to pressurize the rod side chamber S1 before injection of the molten metal by the plunger 6 is started. It is Specifically, the pressure increasing portion 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 to connect the rod side chamber S1 and the pressurizing section 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 In other words, the control device 8 is configured to perform control to pressurize the rod-side chamber S1 by the pressure intensifying section 375 in the pressurizing process started at a predetermined timing.

The low-speed injection process, the high-speed injection process, the increased pressure injection process, and the return process are the same as those in the first embodiment, so descriptions thereof will be omitted. Other configurations of the third embodiment are the same as those of the first embodiment.

(Effect of the third embodiment)
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 for switching connection or disconnection between the rod-side chamber S1 and the pressure unit 76 . A switching valve 79 is arranged between the rod-side chamber S<b>1 and the pressurizing portion 76 . Thereby, the piston 71 can be stably advanced in the meter-out control.

Further, in the third embodiment, as described above, the pressure intensifying section 375 is provided also as the pressurizing section 76 of the first embodiment. The pressure increasing portion 375 is configured to be able to pressurize the rod side chamber S1 when the injection of the molten metal by the plunger 6 is started. As a result, an increase in the number of parts can be suppressed compared to the case where the pressure intensifying section and the pressurizing section are provided separately, so that the configuration of the injection device 307 can be suppressed from becoming complicated. Other effects of the third embodiment are the same as those of the first embodiment.

[Modification]
It should be noted that the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the description of the above-described embodiments, and includes all modifications within the meaning and scope equivalent to the scope of the claims.

For example, in the first and third embodiments, the switching valve 79 (switching portion) connects the rod side chamber S1 and the pressurizing portion 76 (pressure increasing portion 375) and connects the rod side chamber S1 and the tank 73. , rod-side chamber S1, pressurizing portion 76 (pressure-increasing portion 375) and tank 73. However, the present invention is not limited to this. In the present invention, the connection between the rod side chamber and the pressurizing section, the connection between the rod side chamber and the pump line, the connection between the rod side chamber and the tank, and the connection between the rod side chamber and the pressurizing section, the tank, and the pump line are disconnected. It may be a four-way valve or the like that switches between four connection states.

In the first and third embodiments, the switching valve 79 is a hydraulic servo valve (electrohydraulic switching valve), 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 electrically operated servovalve.

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

Further, in the above-described first to third embodiments, an example in which the die casting machine 1 (301) is configured horizontally has been shown, but the present invention is not limited to this. In the present invention, the die casting machine may be configured vertically.

In addition, 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 process based on the tip position of the plunger 6 detected by the position sensor 74. Although an example configured to determine the start of the process and the return process has been shown, the present invention is not limited to this. For example, the controller may be configured to determine the start of the low-speed injection process, the high-speed injection process, the boost 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, an example in which the control device 8 (control section) drives the pressure section 76 using the timer section 81 has been described, but the present invention is not limited to this. In the present invention, the control section may cause the injection processing section to drive the pressure section without using the timer section.

Further, in the first embodiment, for convenience of explanation, the processing operation of the control device 8 (control unit) was explained using a flow-driven flowchart in which processing is performed in order according to the processing flow. is not limited to In the present invention, the processing operation of the control unit may be performed by event-driven processing that executes processing on an event-by-event basis. In this case, it may be completely event-driven, or a combination of event-driven and flow-driven.

Reference Signs List 1 die casting machine 6 plunger 7, 207, 307 injection device 8, 308 control device (control section)
71 piston 72 cylinder 73 tank 75, 375 pressure increasing unit 76 pressure increasing unit 77 pump line (hydraulic oil supply source)
78 Check valve 79 Switching valve (switching part)
94 fourth channel (channel)
279a 1st switching valve (switching part)
279b Second switching valve (switching part)
S cylinder chamber S1 rod side chamber S2 head side chamber

Claims (10)

a piston connected to the plunger;
a cylinder containing the piston and including a cylinder chamber divided into a rod-side chamber and a head-side chamber by the piston;
an accumulator that causes hydraulic oil to flow into the head-side chamber to advance the piston;
a pump line for supplying hydraulic oil to the rod-side chamber when the piston is retracted and returned to the return position;
a pressurizing unit that pressurizes the rod-side chamber before injection of the molten metal by the plunger is started;
a first flow path connecting the pressurizing portion and the rod-side chamber;
a switching portion disposed in the first flow path for switching connection or disconnection between the rod-side chamber and the pressurizing portion;
a second flow path branched from the first flow path and connected to the pump line;
A third flow path provided separately from the first flow path and connected to the accumulator and the head-side chamber,
The injection device, wherein the switching section is arranged between the rod-side chamber and the pressurizing section in the first flow path provided separately from the third flow path. 2. The injection device according to claim 1, further comprising a control section that performs control such that the switching section disconnects the rod-side chamber from the pressurizing section when injection of the molten metal by the plunger is started. further comprising a tank from which hydraulic oil in the rod side chamber is discharged,
The switching unit is configured to be capable of switching 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 section disconnects the rod-side chamber and the pressurizing section by the switching section, and disconnects the rod-side chamber and the tank by the switching section. 3. An injection device according to claim 2, configured to control the connection. 2. 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 injection of the molten metal by the plunger is started. 4. 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 injection of the molten metal by the plunger is started, and the rod side chamber is kept open for a predetermined time by the pressurizing unit. 5. The injection device according to claim 4, configured to perform pressurization control. The switching unit is a switching valve that switches connection between the rod-side chamber and the pressurizing unit, connection between the rod-side chamber and the tank, and disconnection of connection between the rod-side chamber and the pressurizing unit and the tank. 4. The injection device of 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. ,
4. The injection device according to claim 3, wherein the control section is configured to perform control of synchronously switching the first switching valve and the second switching valve. a pressure increasing unit for increasing the pressure of the head-side chamber by supplying hydraulic oil to the head-side chamber before injection of the molten metal by the plunger is completed;
8. The pressurizing unit according to claim 1, wherein the pressurizing unit is provided separately from the pressurizing unit, and configured to pressurize the rod side chamber before injection of the molten metal by the plunger is started. 1. The injection device according to claim 1. 9. The check valve according to any one of claims 1 to 8, further comprising a check valve arranged upstream from a branch of said second flow path to said first flow path and downstream of said pump line. injection device. a cylindrical sleeve having a pouring port into which the molten metal is poured by the pouring mechanism;
a plunger for injecting 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 a cylinder chamber containing the piston and having an internal space divided into a rod-side chamber and a head-side chamber by the piston;
an accumulator that causes hydraulic oil to flow into the head-side chamber to advance the piston;
a pump line for supplying hydraulic oil to the rod-side chamber when the piston is retracted and returned to the return position;
a pressurizing unit that pressurizes the rod-side chamber before injection of the molten metal by the plunger is started;
a first flow path connecting the pressurizing portion and the rod-side chamber;
a switching portion disposed in the first flow path for switching connection or disconnection between the rod-side chamber and the pressurizing portion;
a second flow path branched from the first flow path and connected to the pump line;
A third flow path provided separately from the first flow path and connected to the accumulator and the head-side chamber,
The die casting machine, wherein the switching section is arranged between the rod-side chamber and the pressurizing section in the first flow path provided separately from the third flow path.

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