JP7168706B2 - Injection device, molding machine, and control method for molding machine - Google Patents

Description

The present invention relates to an injection device for filling a cavity in a mold with a liquid material, a molding machine, and a control method for the molding machine.

A die-cast machine manufactures a molded product (die-cast product) by using an injection device to fill a cavity in a mold clamped by a mold clamping device with molten metal. The injection device includes, for example, an injection cylinder as an actuator. The injection cylinder includes, for example, a rod connectable to a plunger that slides within a sleeve, an injection piston fixed to the rod, and a cylinder tube that slidably houses the piston therein. The cylinder tube has therein a rod-side chamber in which the rod is arranged and a head-side chamber located on the opposite side of the rod-side chamber with the injection piston interposed therebetween.

The injection piston moves toward the rod side by supplying hydraulic oil to the head-side chamber. As the injection piston moves, the plunger advances through the sleeve toward the mold, filling the cavity in the mold with molten metal.

The speed of the injection piston is controlled, for example, by controlling the flow rate of hydraulic fluid discharged from the rod-side chamber using a flow control valve. This control method is called meter-out control.

When the molten metal is injected by meter-out control, the hydraulic oil in the rod side chamber may be compressed when the hydraulic oil is supplied to the head side chamber, causing the injection piston to suddenly pop out. If the injection piston suddenly protrudes, there is a risk that air will be caught in the molten metal. If air is entrained in the molten metal, the quality of the molded product may deteriorate.

Patent Literature 1 describes an injection device that includes an auxiliary hydraulic supply unit that replenishes hydraulic fluid when the pressure of hydraulic fluid in the rod-side chamber is below a reference value in order to suppress sudden ejection of the injection piston. there is

For example, an injection device is also used when extruding a molded product from a mold. By advancing the injection piston, the part is forced out of the plunger and out of the mold. A pressure shock occurs when the injection piston suddenly ejects when the molded product is pushed out of the mold. The occurrence of pressure shock can lead to failure of the molded product and damage to the structure of the die casting machine.

The injection device is also used, for example, during maintenance of the die casting machine. For example, an injection device is used to move the plunger within the sleeve. When the plunger is moved, if the injection piston suddenly protrudes, the accuracy of position control of the plunger decreases.

JP 2019-72751 A

The problem to be solved by the present invention is to provide an injection device, a molding machine, and a control method for the molding machine that can suppress sudden projection of the piston.

An injection device of one aspect of the present invention includes a rod connectable to a plunger that slides in a sleeve, a piston fixed to the rod, a cylinder tube that slidably houses the piston, and the rod: an injection cylinder including a rod-side chamber and a head-side chamber located on the opposite side of the rod-side chamber with the piston interposed therebetween; a hydraulic pump with a variable discharge rate of hydraulic fluid; a flow control valve that controls the flow rate of the discharged hydraulic fluid and opens independently of the pressure of the hydraulic fluid in the head-side chamber; and the flow control valve opens when the piston is advanced toward the rod side. a control unit for controlling the discharge amount of the hydraulic fluid from the hydraulic pump in the above state, and changing the supply amount of the hydraulic fluid to the head-side chamber so as to increase continuously or stepwise.

In the injection apparatus of the aspect described above, it is preferable that the control unit changes the amount of change in the discharge amount of the hydraulic fluid from the hydraulic pump.

The injection apparatus of the above aspect further includes a pressure sensor that measures the pressure of the working fluid in the head-side chamber, and the control unit, based on the pressure of the working fluid in the head-side chamber measured by the pressure sensor, It is preferable to change the amount of change in the discharge amount of the hydraulic fluid of the hydraulic pump.

In the injection apparatus of the aspect described above, the control unit reduces the discharge amount of the hydraulic fluid from the hydraulic pump when the pressure of the hydraulic fluid in the head-side chamber measured by the pressure sensor reaches a predetermined pressure. It is preferable to reduce the amount of change.

The injection apparatus of the above aspect further comprises a position sensor for measuring the position of the rod or the piston, and the control unit controls the hydraulic pump based on the position of the rod or the piston measured by the position sensor. It is preferable to change the amount of change in the discharge amount of the hydraulic fluid.

In the injection apparatus of the above aspect, the control unit discharges the hydraulic fluid from the hydraulic pump based on the speed of the rod or the piston calculated from the position of the rod or the piston measured by the position sensor. It is preferable to vary the amount of change in quantity.

In the injection device of the aspect described above, an accumulator for increasing the flow rate of the hydraulic fluid supplied to the head-side chamber, a first flow path for supplying the hydraulic fluid to the accumulator using the hydraulic pump, a second flow path that supplies the hydraulic fluid to the head-side chamber using the accumulator; a third flow path that discharges the hydraulic fluid from the rod-side chamber and has the flow control valve; and the hydraulic pump. and a fourth flow path different from the first flow path, wherein the control unit controls the hydraulic pump and the fourth flow path to supply the hydraulic fluid to the head-side chamber using It is preferable that the hydraulic fluid is supplied to the head-side chamber using a head-side chamber.

A molding machine according to one aspect of the present invention includes the injection device, a mold clamping device that clamps a mold, and an extrusion device that extrudes a molded product from the mold, wherein the injection device Inject a liquid material into it.

A molding machine control method according to one aspect of the present invention includes a mold clamping device that clamps a mold, an extrusion device that pushes a molded product out of the mold, and a rod that can be connected to a plunger that slides in a sleeve. a piston fixed to the rod; a cylinder tube slidably housing the piston; a rod-side chamber in which the rod is disposed; and a head located on the opposite side of the rod-side chamber with the piston interposed therebetween a side chamber; a hydraulic pump capable of varying the discharge rate of hydraulic fluid; and an injection device for injecting a liquid material into the mold using the plunger , wherein the piston advances toward the rod. When the flow rate control valve is open, the amount of hydraulic fluid discharged from the hydraulic pump is controlled so that the amount of hydraulic fluid supplied to the head-side chamber increases continuously or stepwise. change to

In the method for controlling a molding machine according to the aspect described above, it is preferable to change the amount of change in the amount of discharge of the hydraulic fluid from the hydraulic pump.

In the method for controlling a molding machine according to the aspect described above, the injection device further includes a pressure sensor that measures the pressure of the hydraulic fluid in the head-side chamber, and the pressure of the hydraulic fluid in the head-side chamber measured by the pressure sensor. It is preferable to change the amount of change in the discharge amount of the hydraulic fluid from the hydraulic pump based on the above.

In the molding machine control method of the aspect described above, when the pressure of the working fluid in the head-side chamber measured by the pressure sensor reaches a predetermined pressure, the amount of change in the discharge amount of the working fluid from the hydraulic pump is preferably reduced.

In the method for controlling a molding machine according to the aspect described above, it is preferable that the molded product formed in the mold is extruded by advancing the piston toward the rod.

In the molding machine control method of the above aspect, the injection device further includes a position sensor for measuring the position of the rod or the piston, and based on the position of the rod or the piston measured by the position sensor, the It is preferable to change the amount of change in the discharge amount of the working fluid of the hydraulic pump.

In the molding machine control method of the above aspect, the discharge amount of the hydraulic fluid of the hydraulic pump is adjusted based on the speed of the rod or the piston calculated from the position of the rod or the piston measured by the position sensor. It is preferable to change the amount of change.

According to the present invention, it is possible to provide an injection device, a molding machine, and a control method for a molding machine that can suppress sudden projection of a piston.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows the whole structure of the molding machine of 1st Embodiment. 1 is a schematic diagram showing the configuration of an injection device according to a first embodiment; FIG. Explanatory drawing of the control method of the molding machine of 1st Embodiment. Explanatory drawing of the control method of the molding machine of 1st Embodiment. Explanatory drawing of the control method of the molding machine of 1st Embodiment. Explanatory drawing of the control method of the molding machine of 1st Embodiment. Explanatory drawing of the control method of the molding machine of 1st Embodiment. FIG. 5 is an explanatory diagram of a control method of a molding machine in a comparative example of the first embodiment; FIG. 5 is an explanatory diagram of a control method of a molding machine according to a modification of the first embodiment; The schematic diagram which shows the structure of the injection device of 2nd Embodiment. Explanatory drawing of the control method of the molding machine of 2nd Embodiment. Explanatory drawing of the control method of the molding machine of 2nd Embodiment. Explanatory drawing of the control method of the molding machine of 2nd Embodiment. Explanatory drawing of the control method of the molding machine of 2nd Embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In this specification, hydraulic pressure will be used as an example of the hydraulic pressure. For example, description will be made using a hydraulic pump as an example of the hydraulic pump. Instead of hydraulic pressure, it is also possible to use, for example, water pressure. Further, in this specification, description will be made using hydraulic oil as an example of the hydraulic fluid.

(First embodiment)
The injection device of the first embodiment includes a rod connectable to a plunger that slides in a sleeve, a piston fixed to the rod, a cylinder tube that slidably houses the piston, and a rod. an injection cylinder including a rod-side chamber and a head-side chamber located on the opposite side of the rod-side chamber with the piston interposed therebetween; a hydraulic pump; , When the piston is advanced toward the rod side, the flow rate control valve is opened to control the amount of hydraulic fluid discharged from the hydraulic pump, and the amount of hydraulic fluid supplied to the head-side chamber increases continuously or stepwise. and a control unit that changes so as to

The molding machine of the first embodiment includes the injection device, a mold clamping device that clamps the mold, and an extrusion device that extrudes the molded product from the mold. Inject liquid material.

FIG. 1 is a schematic diagram showing the overall configuration of the molding machine of the first embodiment. FIG. 1 is a side view partially including a cross-sectional view. A molding machine of the first embodiment is a die casting machine 100 . The die casting machine 100 is, for example, a cold chamber type die casting machine.

The die casting machine 100 comprises a mold clamping device 10 , an extrusion device 12 , an injection device 14 , a mold 18 and a control unit 20 .

Die casting machine 100 comprises base 22 , fixed die plate 24 , movable die plate 26 , link housing 28 , tie bar 30 , sleeve 31 and plunger 33 . The plunger 33 has a plunger tip 33a and a plunger rod 33b.

The die casting machine 100 injects and fills a liquid metal (molten metal) into the mold 18 (cavity Ca in FIG. 1), and solidifies the liquid metal in the mold 18 to produce a die cast product (molded product ) is a machine that manufactures Metals are, for example, aluminum, aluminum alloys, zinc alloys, or magnesium alloys. Liquid metal (molten) is an example of a liquid material.

The mold 18 includes a fixed mold 18a and a movable mold 18b. A mold 18 is provided between the mold clamping device 10 and the injection device 14 .

A fixed die plate 24 is fixed on the base 22 . The stationary die plate 24 can hold the stationary die 18a.

The movable die plate 26 is provided on the base 22 so as to be movable in the mold opening/closing direction. The mold opening/closing direction means both the mold opening direction and the mold closing direction shown in FIG. The movable die plate 26 can hold the movable mold 18b facing the fixed mold 18a.

A link housing 28 is provided on the base 22 . One end of a link mechanism that constitutes the mold clamping device 10 is fixed to the link housing 28 .

Fixed die plate 24 and link housing 28 are fixed by tie bars 30 . The tie bar 30 supports the mold clamping force while the mold clamping force is applied to the fixed mold 18a and the movable mold 18b.

The mold clamping device 10 has a function of opening and closing the mold 18 and clamping the mold.

The injection device 14 has a function of injecting the molten metal into the cavity Ca of the mold 18 and pressurizing the molten metal. The injection device 14 comprises a rod 80 connectable to a plunger 33 that slides within the sleeve 31 .

The extruding device 12 has a function of extruding the manufactured die cast product from the mold 18 .

The sleeve 31 communicates with the cavity Ca of the mold 18 . The sleeve 31 is, for example, a cylindrical member connected to the stationary mold 18a. The sleeve 31 is, for example, cylindrical.

A plunger 33 slides within the sleeve 31 . Plunger 33 includes a plunger tip 33a and a plunger rod 33b. A plunger tip 33a fixed to the tip of the plunger rod 33b slides in the sleeve 31 in the front-rear direction. The forward sliding of the plunger tip 33 a within the sleeve 31 pushes the molten metal within the sleeve 31 into the die 18 .

Control unit 20 includes a control device 32 , an input device 34 and a display device 36 . The control unit 20 has a function of controlling the molding operation of the die casting machine 100 using the mold clamping device 10 , the extrusion device 12 and the injection device 14 .

The input device 34 accepts an operator's input operation. The operator can use the input device 34 to set molding conditions and the like for the die casting machine 100 . The input device 34 is, for example, a touch panel using a liquid crystal display or an organic EL display.

The display device 36 displays, for example, the molding conditions and operating conditions of the die casting machine 100 on the screen. The display device 36 is, for example, a liquid crystal display or an organic EL display.

The control device 32 has a function of performing various calculations and outputting control commands to each part of the die casting machine 100 . The control device 32 has, for example, a function of storing molding conditions and the like. The control device 32 controls the operation of the injection device 14, for example.

The control device 32 is configured by, for example, a combination of hardware and software. The control device 32 includes, for example, a CPU (Central Processing Unit), a semiconductor memory, and a control program stored in the semiconductor memory.

FIG. 2 is a schematic diagram showing the configuration of the injection device of the first embodiment.

The injection device 14 has a function of injecting and filling the cavity Ca in the mold 18 with the molten metal in the sleeve 31, for example. The injection device 14 has, for example, a function of pushing out a die cast product from a mold 18 . The injection device 14 has a function of moving the plunger 33 inside the sleeve 31 during maintenance of the die casting machine 100, for example.

The injection device 14 includes an injection cylinder 44, a hydraulic pump 46 (hydraulic pump), an oil tank 48, an accumulator 50, a position sensor 52, a pressure sensor 53, an injection valve 54, a speed control valve 56 (flow control valve), a direction Switching valve 58, first opening/closing valve 60, second opening/closing valve 62, filling/replenishing valve 64, first channel 70a, second channel 70b, third channel 70c, fourth channel 70d, a fifth flow path 70e, a sixth flow path 70f, and a controller 72 (control unit). The hydraulic pump 46 is an example of a hydraulic pump. The speed control valve 56 is an example of a flow control valve. Controller 72 is an example of a control unit.

The injection cylinder 44 includes a rod 80 , an injection piston 82 (piston), a cylinder tube 84 , a rod side chamber 86 and a head side chamber 88 . The injection piston 82 is an example of a piston.

Rod 80 is connectable to plunger 33 which slides within sleeve 31 . Movement of rod 80 moves plunger 33 within sleeve 31 .

An injection piston 82 is fixed to the rod 80 . The injection piston 82 is slidably housed in the cylinder tube 84 . The injection piston 82 is, for example, cylindrical.

The cylinder tube 84 slidably accommodates the injection piston 82 . The cylinder tube 84 is, for example, cylindrical.

A rod-side chamber 86 is provided inside the cylinder tube 84 on the rod 80 side. A rod 80 is arranged in the rod-side chamber 86 .

A head-side chamber 88 is provided inside the cylinder tube 84 on the side opposite to the rod 80 side. The head side chamber 88 is located on the opposite side of the rod side chamber 86 with the injection piston 82 interposed therebetween.

The hydraulic pump 46 is driven by, for example, a pump motor (not shown). The hydraulic pump 46 has a function of drawing up hydraulic oil from an oil tank 48 and discharging it. The hydraulic pump 46 contributes to, for example, supplying hydraulic fluid to the accumulator 50 and supplying hydraulic fluid to the injection cylinder 44 .

The discharge amount or discharge pressure of hydraulic oil discharged by the hydraulic pump 46 is variable. The hydraulic pump 46 is, for example, a variable displacement pump. A variable displacement pump can change the discharge amount and discharge pressure of hydraulic oil.

The oil tank 48 stores hydraulic oil to be supplied to the accumulator 50 and the injection cylinder 44, for example. Also, the oil tank 48 collects hydraulic oil used in the accumulator 50 and the injection cylinder 44, for example.

The accumulator 50 has a function of increasing the flow rate of hydraulic oil supplied to the head-side chamber 88 . The accumulator 50 accumulates energy using the high-pressure sealed gas, and releases the energy momentarily to increase the flow rate of hydraulic oil. By providing the accumulator 50, the injection cylinder 44 can be operated at high speed.

A first flow path 70 a connects the hydraulic pump 46 and the accumulator 50 . Using the first flow path 70a, hydraulic fluid can be supplied from the hydraulic pump 46 to the accumulator 50 to fill the accumulator 50 with hydraulic fluid and accumulate pressure.

Also, the first flow path 70a is connected to the head-side chamber 88 via the second flow path 70b. During the injection operation of the injection cylinder 44, the hydraulic oil can be replenished to the second flow path 70b using the first flow path 70a.

70 f of 6th flow paths connect the hydraulic pump 46 and the head side chamber 88 via 70 d of 4th flow paths. The sixth flow path 70f is a so-called pump line. Hydraulic oil can be supplied from the hydraulic pump 46 to the head-side chamber 88 using the sixth flow path 70f and the fourth flow path 70d. The fourth channel 70d is different from the first channel 70a.

Also, the sixth flow path 70f connects the hydraulic pump 46 and the rod side chamber 86 via the fifth flow path 70e. Hydraulic oil can be supplied from the hydraulic pump 46 to the rod side chamber 86 using the sixth flow path 70f and the fifth flow path 70e.

A third flow path 70 c connects the rod side chamber 86 and the oil tank 48 . It is possible to recover hydraulic fluid discharged from the rod-side chamber 86 to the oil tank 48 using the third flow path 70c.

The first flow path 70a to the sixth flow path 70f are configured by steel pipes or hoses, for example.

The injection valve 54 is provided in the second flow path 70b. The injection valve 54 is provided between the head side chamber 88 and the accumulator 50 . The injection valve 54 allows or blocks the supply of hydraulic oil from the accumulator 50 to the head-side chamber 88 .

The injection valve 54 is composed of, for example, a pilot-type check valve, and when the pilot pressure is not introduced, the hydraulic oil is allowed to flow from the accumulator 50 to the head-side chamber 88 and in the opposite direction. block the flow of When the pilot pressure is introduced to the injection valve 54, both flows are blocked. The injection valve 54 has a function of preventing backflow of hydraulic oil from the head-side chamber 88 to the accumulator 50 .

Hydraulic oil is permitted to flow from the accumulator 50 to the head-side chamber 88 when the injection valve 54 is open. When the injection valve 54 is closed, the flow of hydraulic oil from the accumulator 50 to the head-side chamber 88 is blocked.

A speed control valve 56 is provided in the third flow path 70c. The speed control valve 56 is provided between the rod side chamber 86 and the oil tank 48 . The speed control valve 56 controls the flow rate of hydraulic oil discharged from the rod-side chamber 86 to the oil tank 48 .

The forward speed of the injection piston 82 is controlled by controlling the flow rate of hydraulic oil by the speed control valve 56 . A so-called meter-out control is performed by the speed control valve 56 . When the speed control valve 56 is closed, the hydraulic fluid flow between the rod side chamber 86 and the oil tank 48 is blocked.

The type of the speed control valve 56 is not particularly limited as long as the flow rate of hydraulic oil can be controlled. The speed control valve 56 may be, for example, a pressure-compensating valve or a non-pressure-compensating valve. Further, the speed control valve 56 may be, for example, a servo valve for which feedback control is performed, or a proportional valve for which open control is performed.

The direction switching valve 58 is provided between the sixth flow path 70f and the fourth flow path 70d and between the sixth flow path 70f and the fifth flow path 70e. The direction switching valve 58 is provided between the head side chamber 88 and the hydraulic pump 46 and between the rod side chamber 86 and the hydraulic pump 46 .

The direction switching valve 58 has a function of switching the flow path of hydraulic oil supplied from the hydraulic pump 46 through the sixth flow path 70f between the fourth flow path 70d and the fifth flow path 70e. . The direction switching valve 58 has a function of switching the supply destination of hydraulic oil supplied from the hydraulic pump 46 between the head side chamber 88 and the rod side chamber 86 .

For example, by supplying hydraulic oil to the head-side chamber 88, the injection piston 82 advances. Further, for example, by supplying hydraulic oil to the rod-side chamber 86, the injection piston 82 retreats.

The type of the direction switching valve 58 is not particularly limited as long as it can switch the direction of flow of hydraulic oil supplied from the hydraulic pump 46 . The direction switching valve 58 is, for example, an electromagnetic switching valve that uses an electromagnet to move the spool.

The first open/close valve 60 is provided in the fourth flow path 70d. A first opening/closing valve 60 is provided between the head-side chamber 88 and the direction switching valve 58 . The first open/close valve 60 permits or blocks the flow of hydraulic oil between the direction switching valve 58 and the head side chamber 88 .

When the first open/close valve 60 is open, hydraulic fluid is allowed to flow between the direction switching valve 58 and the head-side chamber 88 . When the first open/close valve 60 is closed, the hydraulic fluid flow between the direction switching valve 58 and the head side chamber 88 is blocked.

The type of the first opening/closing valve 60 is not particularly limited as long as it can allow and block the flow of hydraulic oil.

The second open/close valve 62 is provided in the fifth flow path 70e. The second opening/closing valve 62 is provided between the rod side chamber 86 and the direction switching valve 58 . The second open/close valve 62 permits or blocks the flow of hydraulic oil between the direction switching valve 58 and the rod side chamber 86 .

When the second open/close valve 62 is open, hydraulic fluid is allowed to flow between the direction switching valve 58 and the rod side chamber 86 . When the second open/close valve 62 is closed, the hydraulic fluid flow between the direction switching valve 58 and the rod side chamber 86 is blocked.

The type of the second opening/closing valve 62 is not particularly limited as long as it can allow and block the flow of hydraulic oil.

A filling replenishment valve 64 is provided in the first flow path 70a. A filling replenishment valve 64 is provided between the accumulator 50 and the hydraulic pump 46 . A filling replenishment valve 64 is provided between the head-side chamber 88 and the hydraulic pump 46 .

A fill refill valve 64 may, for example, allow or block hydraulic fluid flow between the accumulator 50 and the hydraulic pump 46 . The fill refill valve 64 allows or blocks hydraulic fluid flow between the head side chamber 88 and the hydraulic pump 46, for example.

The type of filling replenishment valve 64 is not particularly limited as long as it can allow and block the flow of hydraulic oil.

Position sensor 52 has a function of detecting the position of rod 80 . The position sensor 52 is, for example, an optical or magnetic linear encoder. By differentiating the position of the rod 80 detected by the position sensor 52, the speed of the rod 80 can be detected.

The pressure sensor 53 has the function of measuring the pressure of hydraulic fluid in the head side chamber 88 .

The controller 72 includes, for example, an injection cylinder 44, a hydraulic pump 46, an oil tank 48, an accumulator 50, an injection valve 54, a speed control valve 56, a direction switching valve 58, a first opening/closing valve 60, and a second opening/closing valve 62. , and the operation of the fill refill valve 64 .

For example, when advancing the injection piston 82 toward the rod 80 side, the controller 72 controls the discharge amount of hydraulic oil from the hydraulic pump 46 with the speed control valve 56 opened to a predetermined degree of opening. It has a function to change the amount of hydraulic oil supplied to 88 so as to increase continuously or stepwise.

The controller 72 has a function of changing the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 . In other words, it has a function of changing the discharge amount per unit time of the hydraulic pump 46 .

The controller 72 has a function of changing the amount of change in the discharge amount of the hydraulic pump 46 based on the pressure of the hydraulic oil in the head side chamber 88 measured by the pressure sensor 53, for example. The controller 72 has a function of reducing the amount of change in the amount of hydraulic fluid discharged from the hydraulic pump 46, for example, when the pressure of hydraulic fluid in the head side chamber 88 measured by the pressure sensor 53 reaches a predetermined pressure.

The controller 72 has, for example, a function of controlling the hydraulic oil to be supplied to the head-side chamber 88 using the hydraulic pump 46 and the fourth flow path 70d.

The controller 72 is configured by, for example, a combination of hardware and software. The controller 72 includes, for example, a CPU, a semiconductor memory, and a control program stored in the semiconductor memory.

Controller 72 is, for example, part of controller 32 .

Next, an example of a control method for the die casting machine 100 will be described. In particular, a method of controlling the injection device 14 of the die casting machine 100 will be described.

Among the methods for controlling the injection device 14 of the die casting machine 100, a case in which the injection device 14 is used to extrude the manufactured die cast product from the mold 18 will be described.

Descriptions of controls other than the control method of the injection device 14 of the die casting machine 100, such as the control of the mold clamping device 10 and the extrusion device 12, are partially omitted.

FIG. 3 is an explanatory diagram of the control method of the molding machine of the first embodiment.

When manufacturing a die cast product with the die casting machine 100 , the mold 18 is clamped using the mold clamping device 10 . The injection device 14 is used to inject and fill the cavity Ca in the clamped mold 18 with molten metal.

After the molten metal has solidified, the die casting 99 is extruded and removed from the mold. At this time, as shown in FIG. 3, the fixed mold 18a and the movable mold 18b are opened. By advancing the injection piston 82, the die cast product 99 is pushed out by the plunger 33 and removed from the fixed mold 18a. Thereafter, the die-cast product 99 is extruded using the extruder 12 and removed from the movable mold 18b.

4, 5, 6, and 7 are explanatory diagrams of the control method of the molding machine of the first embodiment. FIG. 4 is a timing chart. FIG. 4 shows the discharge amount of the hydraulic pump 46, the command to supply hydraulic fluid to the head side chamber 88, the command to discharge hydraulic fluid from the rod side chamber 86, the pressure of the hydraulic fluid in the sixth flow path 70f which is the pump line, the head The timing of the time change of the hydraulic oil pressure in the side chamber 88 is shown.

5, 6, and 7 are explanatory diagrams of the operation of the injection device 14 of the die casting machine 100. FIG.

FIG. 5 is a diagram showing the state of the injection device 14 at time t0 in FIG. FIG. 5 shows the state of the injection device 14 after the molten metal in the cavity Ca within the mold 18 has solidified.

Hydraulic pump 46 is in a stopped state. The injection valve 54, the speed control valve 56 (flow rate control valve), the direction switching valve 58, the first opening/closing valve 60, the second opening/closing valve 62, and the filling/refilling valve 64 are closed.

FIG. 6 is a diagram showing the state of the injection device 14 at time t1 in FIG.

A command from the controller 72 causes the hydraulic pump 46 to operate. The discharge amount of hydraulic oil discharged from the hydraulic pump 46 changes so as to increase continuously. The discharge amount of hydraulic oil discharged from the hydraulic pump 46 changes so as to gradually increase.

Hydraulic oil is supplied to the head-side chamber 88 according to a command from the controller 72 . Specifically, for example, according to a command from the controller 72 , the direction switching valve 58 operates so that the hydraulic oil supplied from the hydraulic pump 46 is supplied to the head side chamber 88 .

In addition, it becomes possible to discharge hydraulic oil from the rod side chamber 86 by a command from the controller 72 . Specifically, for example, a command from the controller 72 opens the speed control valve 56 to a predetermined degree of opening, making it possible to discharge hydraulic oil from the rod-side chamber 86 .

The first opening/closing valve 60 is opened by a command from the controller 72 . The injection valve 54, the second opening/closing valve 62, and the filling/refilling valve 64 are closed. White arrows indicate the flow of hydraulic oil.

FIG. 7 is a diagram showing the state of the injection device 14 from time t2 to t4 in FIG.

At time t2, the head-side chamber 88 is filled with hydraulic fluid, and the pressure of hydraulic fluid in the sixth flow path 70f, which is the pump line, and the pressure of hydraulic fluid in the head-side chamber 88 begin to increase. The pressure of hydraulic fluid in the head-side chamber 88 is measured by a pressure sensor 53, for example.

After time t2, hydraulic fluid is discharged from the rod-side chamber 86, and the injection piston 82 advances toward the rod 80 side. The rod 80 fixed to the injection piston 82 and the plunger 33 fixed to the rod 80 also move forward. As the plunger 33 moves forward, the die cast product 99 is pushed out by the plunger 33 and removed from the fixed mold 18a.

For example, when the pressure of hydraulic fluid in the head-side chamber 88 measured by the pressure sensor 53 at time t3 reaches a predetermined pressure Px, a command from the controller 72 causes the amount of hydraulic fluid discharged from the hydraulic pump 46 to increase. Reduce the amount of change. In other words, the discharge amount per unit time of the hydraulic pump 46 is reduced.

Feedback control is performed to feed back the pressure of the hydraulic fluid in the head-side chamber 88 measured by the pressure sensor 53 to the amount of change in the amount of hydraulic fluid discharged from the hydraulic pump 46 .

Next, the operation and effects of the injection device 14, the die casting machine 100, and the control method for the die casting machine 100 of the first embodiment will be described.

In a die casting machine, an injection cylinder is also used to push out a die cast product from a mold. By advancing the injection piston, the die cast product is pushed out by the plunger and removed from the mold. When the die casting product is extruded from the mold, a pressure shock occurs when the injection piston suddenly protrudes. The occurrence of pressure shock can lead to damage to the die casting and damage to the structure of the die casting machine.

FIG. 8 is an explanatory diagram of a control method of a molding machine in a comparative example of the first embodiment. FIG. 8 is a timing chart.

A molding machine of a comparative example of the first embodiment has a configuration similar to that of the die casting machine 100 of the first embodiment except for the controller 72 .

FIG. 8 shows the discharge amount of the hydraulic pump 46, the command to supply hydraulic fluid to the head side chamber 88, the command to discharge hydraulic fluid from the rod side chamber 86, the pressure of the hydraulic fluid in the sixth flow path 70f which is the pump line, the head The timing of the time change of the hydraulic oil pressure in the side chamber 88 is shown. FIG. 8 is a diagram corresponding to FIG.

At time t0, the molten metal in the cavity Ca inside the mold 18 has solidified. Hydraulic pump 46 is in a stopped state. The injection valve 54, the speed control valve 56 (flow rate control valve), the direction switching valve 58, the first opening/closing valve 60, the second opening/closing valve 62, and the filling/refilling valve 64 are closed.

At time t1, the hydraulic pump 46 starts operating. The amount of hydraulic oil discharged from the hydraulic pump 46 is constant after time t1. At time t1, the injection valve 54, the speed control valve 56 (flow rate control valve), the direction switching valve 58, the first opening/closing valve 60, the second opening/closing valve 62, and the filling/refilling valve 64 are closed. . Since the direction switching valve 58 and the first opening/closing valve 60 are closed, the pressure of the hydraulic fluid in the sixth flow path 70f, which is the pump line, rises with time.

At time t<b>2 , the direction switching valve 58 is operated by a command from the controller 72 so that the hydraulic oil supplied from the hydraulic pump 46 is supplied to the head side chamber 88 . In addition, the first open/close valve 60 is also opened by a command from the controller 72 . Further, the speed control valve 56 is opened to a predetermined degree of opening by a command from the controller 72, and the hydraulic oil can be discharged from the rod-side chamber 86.

Immediately after time t2, the pressure of the hydraulic fluid in the head-side chamber 88 rises sharply, causing the injection piston 82 to suddenly protrude and generate a pressure shock. The occurrence of pressure shock can lead to damage to the die casting and damage to the structure of the die casting machine.

In the die casting machine 100 of the first embodiment, under the control of the controller 72, the discharge amount of hydraulic oil discharged from the hydraulic pump 46 changes so as to continuously increase. In other words, the amount of hydraulic oil discharged from the hydraulic pump 46 changes gradually.

Therefore, a rapid increase in the pressure of the hydraulic fluid in the head-side chamber 88 is suppressed. Therefore, the sudden ejection of the injection piston 82 is suppressed, and the generated pressure shock is reduced. Therefore, damage to the die-cast product 99 and damage to the structure of the die-cast machine 100 are suppressed.

From the viewpoint of reducing the pressure shock that occurs, feedback control is performed in which the pressure of the hydraulic fluid in the head side chamber 88 measured by the pressure sensor 53 is fed back to the amount of change in the amount of hydraulic fluid discharged from the hydraulic pump 46. is preferred. For example, it is preferable to reduce the amount of change in the amount of hydraulic fluid discharged from the hydraulic pump 46 when the pressure of hydraulic fluid in the head-side chamber 88 reaches a predetermined pressure Px.

FIG. 9 is an explanatory diagram of a control method for a molding machine according to a modification of the first embodiment. FIG. 9 is a timing chart. FIG. 9 is a diagram corresponding to FIG.

The molding machine of the modification of the first embodiment differs from the die casting machine 100 of the first embodiment in that feedback control is not performed. Since the molding machine of the modified example of the first embodiment does not perform feedback control, the structure of the injection device 14 is simplified.

According to the modified example of the first embodiment, as in the first embodiment, the sudden ejection of the injection piston 82 is suppressed and the generated pressure shock is reduced.

As described above, according to the first embodiment, an injection device, a molding machine, and a control method for a molding machine that can suppress sudden ejection of the piston, thereby suppressing damage to the molded product and damage to the structure of the die casting machine are provided. can.

(Second embodiment)
The injection apparatus of the second embodiment differs from the first embodiment in that the control unit changes the amount of change in the amount of hydraulic fluid discharged from the hydraulic pump based on the position of the rod or cylinder measured by the position sensor. It is different from the injection device of the form. In the following, a part of description may be omitted for contents that overlap with the first embodiment.

The molding machine of the second embodiment differs from the molding machine of the first embodiment in that the injection device is different.

A molding machine of the second embodiment is a die casting machine 200 . The die casting machine 200 is, for example, a cold chamber type die casting machine.

A die casting machine 200 includes a mold clamping device 10 , an extrusion device 12 , an injection device 15 , a mold 18 and a control unit 20 .

FIG. 10 is a schematic diagram showing the configuration of the injection device of the second embodiment.

The injection device 15 includes an injection cylinder 44, a hydraulic pump 46 (hydraulic pump), an oil tank 48, an accumulator 50, a position sensor 52, a pressure sensor 53, an injection valve 54, a speed control valve 56 (flow control valve), a direction Switching valve 58, first opening/closing valve 60, second opening/closing valve 62, filling/replenishing valve 64, first channel 70a, second channel 70b, third channel 70c, fourth channel 70d, a fifth flow path 70e, a sixth flow path 70f, and a controller 72 (control unit). The hydraulic pump 46 is an example of a hydraulic pump. The speed control valve 56 is an example of a flow control valve. Controller 72 is an example of a control unit.

The injection cylinder 44 includes a rod 80 , an injection piston 82 (piston), a cylinder tube 84 , a rod side chamber 86 and a head side chamber 88 . The injection piston 82 is an example of a piston.

The controller 72 includes, for example, an injection cylinder 44, a hydraulic pump 46, an oil tank 48, an accumulator 50, an injection valve 54, a speed control valve 56, a direction switching valve 58, a first opening/closing valve 60, and a second opening/closing valve 62. , and the operation of the fill refill valve 64 .

For example, when advancing the injection piston 82 toward the rod 80 side, the controller 72 controls the discharge amount of hydraulic oil from the hydraulic pump 46 with the speed control valve 56 opened to a predetermined degree of opening. It has a function to change the amount of hydraulic oil supplied to 88 so as to increase continuously or stepwise.

The controller 72 has a function of changing the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 . In other words, it has a function of changing the discharge amount per unit time of the hydraulic pump 46 .

The controller 72 has a function of changing the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 based on the position of the rod 80 or the injection piston 82 measured by the position sensor 52, for example. The controller 72 changes the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 based on the speed of the rod 80 or the injection piston 82 calculated from the position of the rod 80 or the injection piston 82 measured by the position sensor 52, for example. It has a function to let

Next, an example of a control method for the die casting machine 200 will be described. In particular, a method for controlling the injection device 15 of the die casting machine 200 will be described.

Among methods for controlling the injection device 15 of the die casting machine 200, a case of moving the plunger 33 in the sleeve 31 using the injection device 15 during maintenance of the die casting machine 200 will be described.

Descriptions of controls other than the control method of the injection device 15 of the die casting machine 200, such as the control of the mold clamping device 10 and the extrusion device 12, are partially omitted.

FIG. 11 is an explanatory diagram of the control method of the molding machine of the second embodiment.

When performing maintenance on the die casting machine 200, the injection device 15 is used to move the plunger 33 inside the sleeve 31, as shown in FIG. At this time, no molten metal exists in the sleeve 31 . Also, there is no die-cast product in the mold 18 .

FIG. 12 is an explanatory diagram of the control method of the molding machine of the second embodiment. FIG. 12 is a timing chart. FIG. 12 shows the discharge amount of the hydraulic pump 46, the command to supply hydraulic fluid to the head side chamber 88, the command to discharge hydraulic fluid from the rod side chamber 86, the pressure of the hydraulic fluid in the sixth flow path 70f which is the pump line, the rod 80 shows the timing of the speed change over time.

At time t0, injection piston 82 and plunger 33 are stationary. Hydraulic pump 46 is in a stopped state. The injection valve 54, the speed control valve 56 (flow rate control valve), the direction switching valve 58, the first opening/closing valve 60, the second opening/closing valve 62, and the filling/refilling valve 64 are closed.

At time t<b>1 , the hydraulic pump 46 starts operating according to a command from the controller 72 . The discharge amount of hydraulic oil discharged from the hydraulic pump 46 changes so as to increase continuously.

Hydraulic oil is supplied to the head-side chamber 88 according to a command from the controller 72 . Specifically, for example, according to a command from the controller 72 , the direction switching valve 58 operates so that the hydraulic oil supplied from the hydraulic pump 46 is supplied to the head side chamber 88 .

In addition, it becomes possible to discharge hydraulic oil from the rod side chamber 86 by a command from the controller 72 . Specifically, for example, a command from the controller 72 opens the speed control valve 56 to a predetermined degree of opening, making it possible to discharge hydraulic oil from the rod-side chamber 86 .

The first opening/closing valve 60 is opened by a command from the controller 72 . The injection valve 54, the second opening/closing valve 62, and the filling/refilling valve 64 are closed.

At time t2, the head-side chamber 88 is filled with hydraulic fluid, and the pressure of the hydraulic fluid in the sixth flow path 70f, which is the pump line, begins to increase.

After time t2, hydraulic fluid is discharged from the rod-side chamber 86, and the injection piston 82 advances toward the rod 80 side. The rod 80 fixed to the injection piston 82 and the plunger 33 fixed to the rod 80 also move forward.

For example, at time t3, the amount of change in the amount of hydraulic fluid discharged from the hydraulic pump 46 is changed. The amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 is changed based on the speed of the rod 80 calculated from the position of the rod 80 measured by the position sensor 52 .

For example, when the speed of the rod 80 reaches a predetermined speed Vx, a command from the controller 72 increases the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 . In other words, the discharge amount per unit time of the hydraulic pump 46 is increased.

By increasing the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46, the amount of change in the speed of the rod 80 also increases. The gradient of the change in velocity of rod 80 becomes steeper.

Feedback control is performed to feed back the speed of the rod 80 calculated from the rod 80 measured by the position sensor 52 to the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 .

For example, after time t4, the amount of hydraulic oil discharged from the hydraulic pump 46 is made constant. After time t4, the speed of rod 80 becomes constant.

Next, the operation and effects of the injection device 15, the die casting machine 100, and the control method of the die casting machine 100 of the second embodiment will be described.

In a die casting machine, an injection cylinder is also used, for example, during maintenance of the die casting machine. For example, an injection cylinder is used to move the plunger within the sleeve. When the plunger inside the sleeve is moved, if the injection piston suddenly protrudes, the accuracy of the position control of the plunger is degraded. For example, the inching accuracy of the plunger is degraded.

FIG. 13 is an explanatory diagram of a control method of a molding machine of a comparative example of the second embodiment. FIG. 13 is a timing chart.

A molding machine of a comparative example of the second embodiment has the same configuration as the die casting machine 200 of the second embodiment except for the controller 72 .

FIG. 13 shows the discharge amount of the hydraulic pump 46, the command to supply hydraulic fluid to the head side chamber 88, the command to discharge hydraulic fluid from the rod side chamber 86, the pressure of the hydraulic fluid in the sixth flow path 70f which is the pump line, the rod 80 shows the timing of the speed change over time. FIG. 13 is a diagram corresponding to FIG.

At time t0, injection piston 82 and plunger 33 are stationary. At time t0, the hydraulic pump 46 is stopped. The injection valve 54, the speed control valve 56 (flow rate control valve), the direction switching valve 58, the first opening/closing valve 60, the second opening/closing valve 62, and the filling/refilling valve 64 are closed.

At time t1, the hydraulic pump 46 is activated. The amount of hydraulic oil discharged from the hydraulic pump 46 is constant. At time t1, the injection valve 54, the speed control valve 56 (flow rate control valve), the direction switching valve 58, the first opening/closing valve 60, the second opening/closing valve 62, and the filling/refilling valve 64 are closed. . Since the direction switching valve 58 and the first opening/closing valve 60 are closed, the pressure of the hydraulic fluid in the sixth flow path 70f, which is the pump line, rises with time.

At time t<b>2 , the direction switching valve 58 is operated by a command from the controller 72 so that the hydraulic oil supplied from the hydraulic pump 46 is supplied to the head side chamber 88 . Also, the first open/close valve 60 is opened. Further, the speed control valve 56 is opened to a predetermined degree of opening by a command from the controller 72, and the hydraulic oil can be discharged from the rod-side chamber 86.

Immediately after time t2, the pressure of the hydraulic fluid in the head-side chamber 88 rises sharply, causing the injection piston 82 to suddenly fly out. As a result, the speed of the rod 80 abruptly fluctuates, and the accuracy of position control of the plunger 33 decreases.

In addition, since there is a time lag between the operation of the hydraulic pump 46 (time t1) and the supply of hydraulic oil to the head-side chamber 88 (time t2), the accuracy of position control of the plunger 33 decreases.

In the die casting machine 200 of the second embodiment, under the control of the controller 72, the discharge amount of hydraulic oil discharged from the hydraulic pump 46 changes so as to continuously increase. In other words, the amount of hydraulic oil discharged from the hydraulic pump 46 changes gradually.

Therefore, a rapid increase in the pressure of the hydraulic fluid in the head-side chamber 88 is suppressed. Therefore, the injection piston 82 is restrained from jumping out abruptly, and the speed of the rod 80 gradually changes. Therefore, the accuracy of position control of the plunger 33 is improved.

Further, since the time lag between the operation of the hydraulic pump 46 and the supply of hydraulic oil to the head-side chamber 88 is small, the accuracy of position control of the plunger 33 is improved. For example, the inching accuracy of the plunger 33 is improved.

From the viewpoint of shortening the movement time of the plunger 33 to the desired position, the speed of the rod 80 calculated from the position of the rod 80 measured by the position sensor 52 is used as the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46. It is preferable to perform feedback control that feeds back to changes. For example, when the speed of the rod 80 reaches a predetermined speed Vx, it is preferable to increase the amount of change in the amount of hydraulic oil discharged from the hydraulic pump 46 according to a command from the controller 72 .

FIG. 14 is an explanatory diagram of a control method for a molding machine according to a modification of the second embodiment. FIG. 14 is a timing chart. FIG. 14 is a diagram corresponding to FIG.

The molding machine of the modified example of the second embodiment differs from the die casting machine 200 of the second embodiment in that feedback control is not performed. Since the molding machine of the modified example of the second embodiment does not perform feedback control, the structure of the injection device 15 is simplified.

According to the modified example of the second embodiment, as in the second embodiment, the injection piston 82 is prevented from jumping out abruptly, and the accuracy of position control of the plunger 33 is improved.

As described above, according to the second embodiment, it is possible to provide an injection apparatus, a molding machine, and a control method for the molding machine that can suppress sudden projection of the piston and improve the accuracy of the position control of the plunger.

In the first and second embodiments, a die-casting machine that fills a mold with molten metal has been described as an example of a molding machine. However, for example, the present invention can also be applied to an injection molding machine that fills a mold with a resin material. It is possible.

It is also possible for the control unit of the injection device to have the functions of both the control units of the first and second embodiments.

The embodiments of the present invention have been described above with reference to specific examples. However, the invention is not limited to these specific examples. In the embodiments, the injection device, the molding machine, and the control method of the molding machine, etc., which are not directly necessary for the explanation of the present invention, are omitted. Elements related to the control method of the molding machine can be appropriately selected and used.

In addition, all injection apparatuses, molding machines, and molding machine control methods that have the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

10 mold clamping device 12 extrusion device 14 injection device 15 injection device 18 mold 31 sleeve 33 plunger 44 injection cylinder 46 hydraulic pump (hydraulic pressure pump)
50 accumulator 52 position sensor 53 pressure sensor 56 speed control valve (flow control valve)
70a First flow path 70b Second flow path 70c Third flow path 70d Fourth flow path 72 Controller (control unit)
80 rod 82 injection piston (piston)
84 Cylinder tube 86 Rod-side chamber 88 Head-side chamber 99 Die-cast product (molded product)
100 die casting machine 200 die casting machine Ca cavity

Claims (15)

a rod connectable to a plunger that slides within the sleeve;
a piston fixed to the rod;
a cylinder tube that slidably accommodates the piston;
a rod-side chamber in which the rod is arranged;
a head-side chamber located on the opposite side of the rod-side chamber with the piston interposed therebetween;
an injection cylinder comprising
a hydraulic pump that can discharge a variable amount of hydraulic fluid;
a flow control valve that controls the flow rate of the hydraulic fluid discharged from the rod side chamber and opens independently of the pressure of the hydraulic fluid in the head side chamber ;
When the piston is advanced toward the rod side, the discharge amount of the hydraulic fluid from the hydraulic pump is controlled while the flow control valve is open, so that the supply amount of the hydraulic fluid to the head-side chamber is continuous. A control unit that changes so as to increase gradually or stepwise,
An injection device comprising: 2. The injection apparatus according to claim 1, wherein the control unit changes the amount of change in the discharge amount of the hydraulic fluid from the hydraulic pump. further comprising a pressure sensor that measures the pressure of the hydraulic fluid in the head-side chamber;
3. The control unit changes the amount of change in the discharge amount of the hydraulic fluid from the hydraulic pump based on the pressure of the hydraulic fluid in the head-side chamber measured by the pressure sensor. injection device. The control unit reduces the amount of change in the discharge amount of the hydraulic fluid from the hydraulic pump when the pressure of the hydraulic fluid in the head-side chamber measured by the pressure sensor reaches a predetermined pressure. 4. An injection device according to claim 3. further comprising a position sensor for measuring the position of the rod or the piston;
3. The injection method according to claim 2, wherein the control unit changes the amount of change in the amount of hydraulic fluid discharged from the hydraulic pump based on the position of the rod or the piston measured by the position sensor. Device. The control unit changes the amount of change in the discharge amount of the hydraulic fluid of the hydraulic pump based on the speed of the rod or the piston calculated from the position of the rod or the piston measured by the position sensor. 6. The injection device according to claim 5, characterized in that: an accumulator for increasing the flow rate of the hydraulic fluid supplied to the head-side chamber;
a first flow path that supplies the hydraulic fluid to the accumulator using the hydraulic pump;
a second flow path that supplies the working fluid to the head-side chamber using the accumulator;
a third channel that discharges the hydraulic fluid from the rod-side chamber and has the flow control valve;
a fourth flow path that supplies the hydraulic fluid to the head-side chamber using the hydraulic pump and is different from the first flow path;
7. The injection molding apparatus according to claim 1, wherein the control unit supplies the working fluid to the head-side chamber using the hydraulic pump and the fourth flow path. Device. an injection device according to any one of claims 1 to 7;
a mold clamping device for clamping the mold;
and an extrusion device for extruding a molded product from the mold,
A molding machine, wherein the injection device injects a liquid material into the mold. a mold clamping device for clamping the mold;
an extrusion device for extruding a molded product from the mold;
a rod connectable to a plunger that slides within the sleeve;
a piston fixed to the rod;
a cylinder tube that slidably accommodates the piston;
a rod-side chamber in which the rod is arranged;
a head-side chamber located on the opposite side of the rod-side chamber with the piston interposed therebetween;
an injection cylinder comprising
a hydraulic pump that can discharge a variable amount of hydraulic fluid;
a flow control valve that controls the flow rate of the hydraulic fluid discharged from the rod side chamber and opens independently of the pressure of the hydraulic fluid in the head side chamber ;
an injection device for injecting a liquid material into the mold using the plunger;
A control method for a molding machine comprising
When the piston is advanced toward the rod side, the discharge amount of the hydraulic fluid from the hydraulic pump is controlled while the flow control valve is open, so that the supply amount of the hydraulic fluid to the head-side chamber is continuous. A method of controlling a molding machine, characterized by changing the value so as to increase it either systematically or stepwise. 10. The method of controlling a molding machine according to claim 9, wherein the amount of change in the amount of discharge of said hydraulic fluid from said hydraulic pump is changed. the injection device further includes a pressure sensor that measures the pressure of the hydraulic fluid in the head-side chamber;
11. The control of the molding machine according to claim 10, wherein the amount of change in the amount of discharge of the hydraulic fluid from the hydraulic pump is changed based on the pressure of the hydraulic fluid in the head-side chamber measured by the pressure sensor. Method. 3. A change amount of the hydraulic fluid discharged from the hydraulic pump is reduced when the pressure of the hydraulic fluid in the head-side chamber measured by the pressure sensor reaches a predetermined pressure. 12. The control method of the molding machine according to 11. 12. The method of controlling a molding machine according to claim 10, wherein the molded product formed in the mold is extruded by advancing the piston toward the rod. the injection device further comprising a position sensor for measuring the position of the rod or the piston;
11. The method of controlling a molding machine according to claim 10, wherein the amount of change in the amount of discharge of the hydraulic fluid from the hydraulic pump is changed based on the position of the rod or the piston measured by the position sensor. The amount of change in the discharge amount of the hydraulic fluid of the hydraulic pump is changed based on the speed of the rod or the piston calculated from the position of the rod or the piston measured by the position sensor. The method of controlling a molding machine according to claim 14.

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