JP2009226449A - Molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding machine in which following the die opening of an injection plunger can be suitably performed while making a hydraulic device compact. <P>SOLUTION: A die casting machine 1 comprises: a die clamping cylinder device 11; an injection plunger 21 sliding inside a sleeve 19 and extruding a molding material; an injection cylinder device 23 driving the injection plunger 21; a pump 33; a motor 35 driving the pump 33; and an accumulator 37. The hydraulic circuit 39 and the controller 41 make the accumulator 37 accumulate pressure by the pump 33, after solidification of the molding material in a cavity Ca, a working liquid is supplied from the pump 33 to the die clamping cylinder device 11 so as to perform die opening, synchronously with the die opening, the working liquid is supplied from the accumulator 37 to the injection cylinder device 23, and a biscuit Dt2 is extruded by the injection plunger 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a molding machine such as a die casting machine.

  In a molding machine such as a die casting machine, a movable mold comes into contact with a fixed mold to close the mold, and a cavity is formed between the fixed mold and the movable mold. Then, the injection plunger slides in the sleeve communicating with the cavity from the back side of the fixed mold, whereby the molding material in the sleeve is injected into the cavity. Thereafter, the molding material is solidified to form a molded product. At this time, the molding material on the front surface of the injection plunger in the sleeve is also solidified to form a biscuit. When the molded product is formed, the die casting machine performs mold opening, and the molded product is released from the fixed mold together with the moving mold. At this time, if the biscuit is fixed to the sleeve, the molded product may be damaged.

Therefore, in Patent Document 1, the injection plunger is advanced following the mold opening, and the biscuit is pushed out from the sleeve to prevent the molded product from being damaged. Specifically, the die casting machine of Patent Document 1 includes a mold opening / closing cylinder device that opens and closes a mold by driving a moving die plate that holds a moving mold, an injection cylinder device that drives an injection plunger, and these cylinder devices. A pump for supplying hydraulic fluid to the pump, a valve for controlling the flow rate of hydraulic fluid from the pump to the mold opening / closing cylinder device, and a valve for controlling the flow rate of hydraulic fluid from the pump to the injection cylinder device. By controlling the flow rate of the liquid, the mold opening / closing cylinder device and the injection cylinder device are synchronously controlled so that the injection plunger follows the mold opening.
JP 09-122880 A

  However, the technique of Patent Document 1 causes various problems because the hydraulic fluid is supplied from one pump to the mold opening / closing cylinder device and the injection cylinder device. For example, the flow control to one side may affect the flow control to the other, and the follow-up to the mold opening of the injection plunger may not be appropriately performed. In addition, it is essential to control the flow rate from the pump to each cylinder device by the flow control valve. In other words, the flow rate of the hydraulic fluid sent from the pump is reduced by the flow control valve to control the flow rate. This is essential, and only a necessary amount of hydraulic fluid cannot be delivered, and energy saving cannot be achieved. However, if a pump is provided corresponding to each of the mold opening / closing cylinder device and the injection cylinder device, the hydraulic device must be enlarged.

  An object of the present invention is to provide a molding machine that can suitably follow the mold opening of an injection plunger while reducing the size of a hydraulic device.

  The molding machine of the present invention includes a fixed die plate that holds a fixed die, a movable die plate that holds a movable die and is movable in a mold opening / closing direction with respect to the fixed die plate, and a movable cylinder that drives the movable die plate An apparatus, a sleeve that passes through the fixed die plate and communicates with a cavity formed in the fixed mold and the movable mold, an injection plunger that slides within the sleeve and extrudes molding material, and drives the injection plunger An injection cylinder device, a pump capable of delivering hydraulic fluid, a motor that drives the pump, an accumulator that holds the hydraulic fluid in an accumulated state, the pump and the accumulator are connected, and the pump and the movement The cylinder device is connected, the accumulator and the injection cylinder device are connected, and the moving cylinder device And a hydraulic circuit that controls the supply of hydraulic fluid to the injection cylinder device, and a control device that controls the hydraulic circuit and the motor. The hydraulic circuit and the control device are controlled by the pump. After accumulating the accumulator and solidifying the molding material in the cavity, hydraulic fluid is supplied from the pump to the moving cylinder device to perform mold opening, and in synchronization with the mold opening, from the accumulator to the injection cylinder apparatus. The hydraulic fluid is supplied, and the biscuit formed by the solidification of the molding material is pushed out by the injection plunger.

  Preferably, the hydraulic circuit and the control device perform high-speed injection by supplying hydraulic fluid from the accumulator to the cylinder device, and perform at least one of low-speed injection and pressure increase from the pump to the injection cylinder device. It is comprised so that it may supply by supplying the hydraulic fluid to.

  Preferably, the hydraulic circuit is provided in a pump-accumulator flow path connecting the pump and the accumulator, and in the pump-accumulator flow path, and allows a flow of hydraulic fluid from the pump to the accumulator. On the other hand, a check valve that prohibits the flow of hydraulic fluid from the accumulator to the pump, and a hydraulic fluid from the position on the pump side of the pump-accumulator flow path to the moving cylinder device from the check valve And a supply control valve for allowing or prohibiting the flow of hydraulic fluid from the accumulator to the injection cylinder device. The moving side direction control valve is controlled so as to prohibit the flow of hydraulic fluid to the moving cylinder device, and the injection cylinder is controlled from the accumulator. The supply control valve is controlled to inhibit the flow of hydraulic fluid to the apparatus, the motor is controlled to drive the pump, the accumulator is accumulated by the pump, and the moving cylinder Control the moving side directional control valve to allow the flow of hydraulic fluid to the device, control the motor to drive the pump, perform mold opening, in synchronization with the mold opening, The supply control valve is controlled to allow the flow of hydraulic fluid from the accumulator to the injection cylinder device, and the biscuit is pushed out by the injection plunger.

  Preferably, the hydraulic pressure circuit is an injection-side direction control capable of allowing or prohibiting the flow of hydraulic fluid from the position on the pump side of the pump-accumulator flow path to the injection cylinder device with respect to the check valve. The control device controls the supply control valve to prohibit the flow of hydraulic fluid from the accumulator to the injection cylinder device, and allows the flow of hydraulic fluid from the pump to the injection cylinder device The injection side direction control valve is controlled to perform low-speed injection, the supply control valve is controlled to allow the flow of hydraulic fluid from the accumulator to the injection cylinder device, and from the pump to the injection cylinder The injection side directional control valve is controlled so as to prohibit the flow of hydraulic fluid to the apparatus, and high speed injection is performed.

  According to the present invention, it is possible to suitably follow the opening of the injection plunger while reducing the size of the hydraulic device.

(First embodiment)
FIG. 1 is a diagram showing a main part of a die casting machine 1 according to the first embodiment of the present invention. Note that, in various embodiments described below, the same reference numerals are given to the same configurations, and descriptions thereof are omitted. Moreover, in FIG. 1, the tank 43 is described in two places for convenience of illustration.

  The die casting machine 1 holds a mold 101 including a fixed mold 103 and a moving mold 105, and performs mold opening and closing and mold clamping of the mold 101, and a cavity Ca ( It has an injection device 5 for injecting and filling molten metal (a molten metal material) as a molding material into a space corresponding to a product part. In addition, the die casting machine 1 includes an extruding device for extruding the molded product Dt formed by solidification of the molten metal from the moving mold 105, but the illustration is omitted.

  The mold clamping device 3 includes, for example, a fixed die plate 7 that holds a fixed mold 103, a movable die plate 9 that holds a movable mold 105, and a movable die plate 9 in a mold opening / closing direction (left and right direction in FIG. 1). And a clamping cylinder device 11 that is driven in a direction opposite to the fixed die plate 7 and the movable die plate 9.

  The mold clamping cylinder device 11 includes, for example, a cylinder tube 13, a piston 15 slidably accommodated in the cylinder tube 13, and a piston rod 17 fixed to the piston 15. The cylinder chamber formed inside the cylinder tube 13 is partitioned by the piston 15 into a rod side chamber Cy1 on the piston rod 17 side and a head side chamber Cy2 on the opposite side, and is selected as the rod side chamber Cy1 and the head side chamber Cy2. When the hydraulic fluid (for example, oil) is supplied, the mold clamping cylinder device 11 is driven.

  In the mold clamping cylinder device 11, for example, the cylinder tube 13 is fixedly provided to the fixed die plate 7 via a base (not shown), and the piston rod 17 is fixed to the moving die plate 9. The die plate 9 can be driven in the mold opening / closing direction.

  The injection device 5 includes a sleeve 19 that communicates with the cavity Ca, an injection plunger 21 that can slide in the sleeve 19, and an injection cylinder device 23 that drives the injection plunger 21.

  The sleeve 19 is formed in, for example, a cylindrical shape, is disposed through the fixed die plate 7, and communicates with the cavity Ca. Molten metal is supplied into the sleeve 19 by a ladle (not shown) and the injection plunger 21 moves forward in the sleeve 19 toward the cavity, whereby the molten metal is injected and filled into the cavity Ca.

  The injection cylinder device 23 is constituted by, for example, a direct-coupled pressure increasing cylinder, and includes a piston rod 25 fixed to the injection plunger 21, an injection piston 27 fixed to the piston rod 25, and an injection piston 27. It has a pressure-increasing piston 29 disposed behind, and a cylinder tube 31 that slidably accommodates the injection piston 27 and the pressure-increasing piston 29.

  The piston rod 25 is connected to the injection plunger 21 coaxially through a coupling, for example. The piston rod 25 may be fixed to the injection plunger 21 by being formed integrally with the injection plunger 21. The injection piston 27 is fixed to the rear end of the piston rod 25. The piston rod 25 and the injection piston 27 may be separately formed and fixed, or may be fixed by being integrally formed.

  The cylinder tube 31 has a tube small-diameter portion 31a on which the injection piston 27 slides, and a tube large-diameter portion 31b that is continuous with the rear end of the tube small-diameter portion 31a and has a larger diameter than the tube small-diameter portion 31a. . The pressure-increasing piston 29 has a piston small-diameter portion 29a that can slide the tube small-diameter portion 31a and a piston large-diameter portion 29b that can slide the tube large-diameter portion 31b.

  The cylinder chamber formed inside the small tube diameter portion 31a is partitioned by the injection piston 27 into a rod side chamber C1 on the piston rod 25 side and a head side chamber C2 on the opposite side. The cylinder chamber formed inside the tube large diameter portion 31b is partitioned into a front chamber C3 on the head side chamber C2 side and a rear chamber C4 on the opposite side by the piston large diameter portion 29b of the pressure increasing piston 29. .

  By supplying the hydraulic fluid to the head side chamber C2, the injection piston 27 advances, and as a result, the injection plunger 21 advances toward the cavity Ca. When the hydraulic fluid is supplied to the rear chamber C4, the pressure of the hydraulic fluid in the rear chamber C4 depends on the ratio of the pressure receiving area of the piston large diameter portion 29b to the pressure receiving area of the piston small diameter portion 29a. The pressure is increased and transmitted to the head side chamber C2, and the molten metal in the cavity Ca is increased by the injection plunger 21.

  The die casting machine 1 includes a pump 33 that can send hydraulic fluid, a motor (electric motor) 35 that drives the pump 33, and hydraulic fluid to which pressure is applied in order to drive the clamping cylinder device 11 and the injection cylinder device 23. An accumulator 37 that holds the fluid, a hydraulic circuit 39 that connects them, and a control device 41 that controls the motor 35 and the hydraulic circuit 39.

  The pump 33 may be a rotary pump that discharges hydraulic fluid by rotation of a rotor such as a gear pump or a vane pump, or the hydraulic fluid is discharged by reciprocation of a piston such as an axial plunger pump or a radial plunger pump. A plunger pump may be used. The pump 33 may be a constant capacity pump in which the discharge amount in one cycle of movement of the rotor or piston is fixed, or may be a variable capacity pump that is variable. The pump 33 only needs to be able to discharge the hydraulic fluid in one direction, but the structure may be the same as that of the bidirectional (two-way) pump. For example, the pump 33 sucks and discharges the hydraulic fluid stored in the tank 43 through the filter 45.

  Although not particularly illustrated, the motor 35 includes a stator that constitutes one of a field and an armature, and a rotor that constitutes the other of the field and the armature and rotates with respect to the stator. The motor 35 may be a direct current motor or an alternating current motor. The motor 35 is constituted by, for example, a servo motor. That is, the motor 35 is provided with a motor sensor 47 such as an encoder that detects the rotation of the motor 35, and feedback control of the motor 35 is performed by a servo driver (servo amplifier) 49 based on the detection value of the motor sensor 47. Made.

  The accumulator 37 is constituted by, for example, a gas pressure type piston accumulator, accumulates the working fluid, and applies the pressure of the compressed gas to the working fluid through the piston. The accumulator 37 may be a gravity type that applies a weight load to the hydraulic fluid, a spring type that applies a restoring force of a spring to the hydraulic fluid, or an operation with gas. It may be of a diaphragm type that separates the liquid from a flexible diaphragm.

  The hydraulic circuit 39 has a first flow path 51 that connects the pump 33 and the accumulator 37, and allows the accumulator 37 to accumulate pressure by the pump 33. In the first flow path 51, for example, a first check valve 53 and a second check valve that allow a flow from the pump 33 side to the accumulator 37 side but prohibit a flow from the accumulator 37 side to the pump 33 side. A valve 55 is provided. The second check valve 55 is provided upstream of the first check valve 53.

  The hydraulic circuit 39 connects the pump 33 and the injection cylinder device 23, and enables the injection cylinder device 23 to be driven by the pump 33. Specifically, the hydraulic circuit 39 includes a second flow path 57 connected to the pump 33, a third flow path 59 connected to the rod side chamber C1 of the injection cylinder device 23, and a head side chamber of the injection cylinder device 23. The fourth flow path 61 connected to C2 and the supply destination of the hydraulic fluid from the second flow path 57 (pump 33) are the third flow path 59 (rod side chamber C1) and the fourth flow path 61 (head side chamber C2). And an injection side direction control valve 63 that can be switched between. In addition, the 2nd flow path 57 is branched from the 1st flow path 51 between the 1st check valve 53 and the 2nd check valve 55, for example.

  The injection side direction control valve 63 is constituted by, for example, a four-port, three-position switching valve, and switches the connection state between the pump 33 and the tank 43 and the rod side chamber C1 and the head side chamber C2. Specifically, it is as follows.

  The injection side direction control valve 63 cuts off the connection between the pump 33 and the tank 43 and the head side chamber C2 and the rod side chamber C1 at the center position (neutral position) among the three positions indicated by the three rectangular symbols. To do. Thereby, the supply of hydraulic fluid from the pump 33 to the head side chamber C2 and the rod side chamber C1 is prohibited.

  The injection side direction control valve 63 connects the pump 33 and the head side chamber C2 and connects the tank 43 and the rod side chamber C1 at the position on the right side of the drawing among the three positions indicated by the three rectangular symbols. When the hydraulic fluid is supplied to the head side chamber C2 by the pump 33, the injection piston 27 and the piston rod 25 move forward to the left side of the drawing. The hydraulic fluid in the rod side chamber C <b> 1 is pushed out by the injection piston 27 and flows into the tank 43.

  The injection-side direction control valve 63 connects the pump 33 and the rod-side chamber C1 and connects the tank 43 and the head-side chamber C2 at a position on the left side of the drawing among three positions indicated by three rectangular symbols. When the hydraulic fluid is supplied to the rod side chamber C1 by the pump 33, the injection piston 27 and the piston rod 25 move backward to the right side of the drawing. The hydraulic fluid in the head side chamber C <b> 2 is pushed out by the injection piston 27 and flows into the tank 43.

  The injection side direction control valve 63 is configured such that the position is switched by sequentially operating an electromagnetic control mechanism and a hydraulic control mechanism, for example, and is switched according to an input electric signal.

  The hydraulic circuit 39 connects the accumulator 37 and the injection cylinder device 23 so that the injection cylinder device 23 can be driven by the accumulator 37. Specifically, it is as follows.

  The hydraulic circuit 39 is provided in the fifth flow path 65 that connects the accumulator 37 and the head side chamber C2 of the injection cylinder device 23, and the fifth flow path 65, and allows or prohibits the flow from the accumulator 37 to the head side chamber C2. Possible supply control valve 67.

  The fifth flow path 65 is connected to the accumulator 37 by being connected to the first flow path 51 on the accumulator 37 side of the second check valve 55, for example. Note that the fifth flow path 65 may be connected to the accumulator 37 separately from the first flow path 51 (part of the first flow path 51 may not be shared).

  For example, the supply control valve 67 is closed when the pilot pressure is introduced, and allows the flow from the accumulator 37 side to the head side chamber C2 side while the pilot pressure is not introduced, while the head side chamber C2. It is constituted by a pilot type check valve that prohibits the flow from the side to the accumulator 37 side. Accordingly, when the introduction of the pilot pressure to the supply control valve 67 is stopped, the working fluid is supplied from the accumulator 37 to the head side chamber C2, and the injection piston 27 and the piston rod 25 move forward to the left side of the drawing.

  The hydraulic circuit 39 has a meter-out circuit for controlling the injection cylinder device 23 when hydraulic fluid is being supplied from the accumulator 37 to the head side chamber C2. Specifically, for example, the hydraulic circuit 39 includes a sixth flow path 69 that connects the rod-side chamber C1 and the tank 43, and an injection-side flow control valve 71 that controls the flow rate of the sixth flow path 69. ing.

  The injection-side flow rate control valve 71 is configured by, for example, a servo valve that is incorporated in a servo mechanism and can modulate the flow rate steplessly in accordance with an input signal. The injection-side flow rate control valve 71 is configured to change the set value of the flow rate by sequentially operating, for example, an electromagnetic control mechanism and a hydraulic control mechanism.

  By controlling the flow rate of the hydraulic fluid discharged from the rod side chamber C1 of the injection cylinder device 23 by the injection side flow rate control valve 71, the speeds of the injection piston 27 and the piston rod 25 of the injection cylinder device 23 are controlled. . The sixth channel 69 is provided with a cooler 72 for cooling the working fluid.

  The hydraulic circuit 39 includes a seventh flow path 75 that connects the accumulator 37 and the rear chamber C4 of the injection cylinder device 23, and a pressure increase side flow control valve 77 provided in the seventh flow path 75.

  For example, the seventh flow path 75 is connected to the accumulator 37 by being connected to the first flow path 51 on the accumulator 37 side of the second check valve 55. In addition, the 7th flow path 75 may be connected to the accumulator 37 separately from the 1st flow path 51 (the 1st flow path 51 and a part may not be made common).

  The pressure-increasing side flow control valve 77 is configured by, for example, a servo valve that is incorporated in a servo mechanism and can modulate the flow rate steplessly according to an input signal. The pressure-increasing side flow rate control valve 77 is configured to change the set value of the flow rate by sequentially operating, for example, an electromagnetic control mechanism and a hydraulic control mechanism.

  By supplying the working fluid from the accumulator 37 to the rear chamber C4 through the seventh flow path 75, the pressure in the head chamber C2 is increased through the pressure-increasing piston 29. At this time, the speed of pressure increase is controlled by the pressure increase side flow control valve 77.

  The hydraulic circuit 39 has an eighth flow path 79 that connects the front chamber C3, the tank 43, and the pump 33. For example, the eighth flow path 79 is connected to the third flow path 59 on the rod side chamber C1 side relative to the injection side direction control valve 63, and to the sixth flow path 69 from the injection side direction control valve 63. Are also connected on the rod side chamber C1 side.

  Therefore, when the hydraulic fluid in the accumulator 37 is supplied to the rear chamber C4 and the pressure-increasing piston 29 moves forward, the hydraulic fluid in the front chamber C3 is discharged to the tank 43 by opening the injection-side flow rate control valve 71. Further, when the injection side direction control valve 63 is switched to the position on the left side in FIG. 1 and hydraulic fluid is supplied from the pump 33 to the rod side chamber C1 and the injection piston 27 moves backward, the pump 33 also returns to the front chamber C3. The hydraulic fluid is supplied and the pressure-increasing piston 29 is also retracted.

  The hydraulic circuit 39 includes a ninth flow path 81 that connects the rear chamber C4 and the tank 43, and a third check valve 82 provided in the ninth flow path 81. For example, the ninth flow path 81 is connected to the fourth flow path 61 on the head side chamber C2 side with respect to the injection side direction control valve 63. The third check valve 82 is provided to allow the flow from the rear side chamber C4 side to the injection side direction control valve 63 side while prohibiting the flow from the injection side direction control valve 63 side to the rear side chamber C4 side. It has been.

  Accordingly, when the injection side direction control valve 63 is switched to the position on the left side of FIG. 2 and hydraulic fluid is supplied from the pump 33 to the front chamber C3 and the pressure increasing piston 29 moves backward, the hydraulic fluid in the rear chamber C4 is It is discharged to the tank 43 through the nine flow paths 81. On the other hand, when the injection side direction control valve 63 is switched to the position on the right side of FIG. 2 and hydraulic fluid is supplied from the pump 33 to the head side chamber C2 and the injection piston 27 moves forward, the third check valve 82 prevents the flow from the pump 33 to the rear chamber C4, and the pressure-increasing piston 29 does not advance.

  The hydraulic circuit 39 connects the pump 33 and the mold clamping cylinder device 11, and enables the pump 33 to drive the mold clamping cylinder device 11. Specifically, the hydraulic circuit 39 includes a tenth flow path 83 connected to the pump 33, an eleventh flow path 84 connected to the tank 43, and these flow paths and the rod side chamber of the mold clamping cylinder device 11. There is a mold clamping side direction control valve 85 for switching the connection state between Cy1 and the head side chamber Cy2. The tenth flow path 83 branches from the first flow path 51, and the eleventh flow path 84 branches from the sixth flow path 69.

  The mold clamping side direction control valve 85 is constituted by a four-port, three-position direction control valve in the same manner as the injection side direction control valve 63, and the center position (neutral position) among the positions indicated by the three rectangles. ), The pump 33 and the tank 43 are disconnected from the rod side chamber Cy1 and the head side chamber Cy2, and the pump 33 and the rod side chamber Cy1 are connected and the tank 43 and the head side chamber Cy2 are connected at the position on the right side of the page. At the position on the left side of the sheet, the pump 33 and the head side chamber Cy2 are connected, and the tank 43 and the rod side chamber Cy1 are connected. In addition, the mold clamping side direction control valve 85 is switched according to the input electric signal, similarly to the injection side direction control valve 63.

  The control device 41 includes, for example, a CPU 86 and a memory 87 such as a ROM or a RAM. The CPU 86 generates a control signal based on various electrical signals input via the input circuit 88 and outputs the generated control signal to various devices via the output circuit 89.

  The electric signal input to the control device 41 includes, for example, a detection signal S1 of the first position sensor 90 that detects the position of the piston rod 25 of the injection cylinder device 23, and a second position sensor 91 that detects the position of the moving die plate 9. Detection signal S2, electric signals P1 to P3 from the first pressure sensor 92, the second pressure sensor 93, and the third pressure sensor 94 for detecting the pressure of the hydraulic fluid, and the user operation from the input device 95 that receives the user operation This is an operation signal according to. The electric signal output from the control device 41 is, for example, a control signal for controlling various valves such as the motor 35 and the injection-side direction control valve 63 and the display device 96 that presents various information to the user.

  The position sensors (first position sensor 90 and second position sensor 91) are, for example, fixedly provided on the measurement object along the advancing and retreating direction of the measurement object (piston rod 17 and moving die plate 9). A magnetic or optical linear encoder is configured together with the scale portion, and a number of pulses corresponding to the amount of movement of the scale portion relative to the position sensor is output. The control device 41 can specify the position and speed (injection speed) of the measurement object by counting the pulses from the position sensor. The position and speed of the piston rod 25 are equivalent to the position and speed of the injection plunger 21.

  The first pressure sensor 92 detects the discharge pressure of the pump 33. Specifically, the pressure of the hydraulic fluid between the first check valve 53, the second check valve 55, and the injection side direction control valve 63 is detected. The second pressure sensor 93 detects the pressure of the working fluid in the accumulator 37. The third pressure sensor 94 detects the pressure of the hydraulic fluid in the head side chamber C2. The pressure in the head side chamber C2 is approximately equal to the pressure (injection pressure) applied by the injection plunger 21 to the molten metal.

  The operation of the die casting machine 1 will be described. First, an outline of the operation of the die casting machine 1 will be described.

  In the die casting machine 1, first, the movable die plate 9 is driven to the fixed die plate 7 side by the mold clamping cylinder device 11, and the mold is closed so that the movable mold 105 is brought into contact with the fixed mold 103. Clamping for increasing the contact pressure between the moving mold 105 and the fixed mold 103 is performed. Thereafter, the injection plunger 21 is driven to the moving mold 105 side by the injection cylinder device 23, and the molten metal is injected and filled into the cavity Ca.

  After filling the molten metal, the molten metal injected into the cavity Ca is continuously given a predetermined pressure by the injection plunger 21. And as time passes, the injected molten metal solidifies and the molded article Dt is formed. The molded product Dt includes a product portion Dt1 formed by solidifying the molten metal in the cavity Ca, and a biscuit Dt2 formed by solidifying the molten metal in the front surface of the injection plunger 21 in the sleeve 19.

  When the molded product Dt is formed, the movable die plate 9 is driven to the opposite side of the fixed die plate 7 by the mold clamping cylinder device 11, and the mold opening is performed. At this time, the molded product Dt moves together with the moving mold 105 and is released from the fixed mold 103. Further, in synchronism with the mold opening, the injection plunger 21 is driven by the injection cylinder device 23 toward the moving mold 105, and the injection plunger 21 pushes out the biscuit Dt 2 from the sleeve 19.

  Thereafter, the injection plunger 21 leaves the moving mold 105 by stopping or retreating. Further, the molded product Dt is extruded from the moving mold 105 by an unillustrated extrusion device. Then, the next cycle is started.

  Next, the details of the injection operation of the die casting machine 1 will be described.

  FIG. 2A is a diagram showing a change with time in the injection pressure in the die casting machine 1, and FIG. 2B is a diagram showing a change with time in the injection speed (speed of the injection plunger) in the die casting machine 1. FIG.

In the die-casting machine 1, when the mold 101 is closed and clamped and the molten metal is supplied into the sleeve 19, the injection plunger 21 starts to move forward, and low-speed injection is performed. In the low speed injection, the injection plunger 21 moves forward at a relatively low speed V _L in order to prevent air from being caught by the molten metal. Incidentally, the injection pressure at which the injection plunger 21 is advanced at a speed V _L is a relatively low pressure P _L.

When the injection plunger 21 reaches a predetermined high-speed switching position (point D in FIG. 2B), the speed of the injection plunger 21 is relatively high from a relatively low speed V _L for the purpose of shortening the cycle time. The speed _VH is switched to high speed injection. The injection pressure when the injection plunger 21 moves forward at the speed V _H is a pressure P _H that is higher than the pressure P _L.

Since the molten metal when it is substantially filled in the cavity Ca (L point in FIG. 2 (b)), the molten metal is pressed by an injection plunger 21 loses escape, injection pressure is rapidly increased from the pressure P _H (pressure P _d ). At the same time, the injection speed is rapidly decelerated from the speed V _H (speed V _d ).

When the high-speed injection is completed, the pressure increase is started (after the point M in FIG. 2B), and the injection speed is further decreased (speed V _t ), while the injection pressure is increased (pressure P _t ). Then, the injection plunger 21 is stopped, the injection pressure becomes the casting pressure (final pressure) _Pmax , and the filling of the molten metal is completed. Thereafter, the injection pressure is maintained at the casting pressure _Pmax . The casting pressure _Pmax is applied from the injection plunger 21 to the molten metal that becomes the product portion Dt1 through the molten metal that becomes the biscuit Dt2.

  In order to realize the operation as described above, the control device 41 controls the motor 35 and various valves as follows.

(Opened state)
The motor 35 is stopped. The accumulator 37 is in an accumulated state. The mold clamping side direction control valve 85 and the injection side direction control valve 63 are in a neutral position. The supply control valve 67, the injection side flow rate control valve 71, and the pressure increase side flow rate control valve 77 are closed.

(Closing mold and clamping)
The control device 41 switches the mold clamping side direction control valve 85 from the neutral position to the position on the left side of FIG. 2 and drives the motor 35 at a predetermined rotational speed. As a result, the hydraulic fluid is supplied from the pump 33 to the head side chamber Cy2 of the mold clamping cylinder device 11, the moving die plate 9 moves to the fixed die plate 7 side, and the mold closing and clamping are performed.

  The speed control of the movable die plate 9 at the time of mold closing and the pressure control at the time of mold clamping are performed by controlling the number of rotations of the motor 35. In the case where the pump 33 is constituted by a variable displacement pump, the displacement is controlled by controlling the discharge amount in one cycle of the pump 33 or by combining the control of the discharge amount and the rotation speed of the motor 35. The speed control of the die plate 9 may be performed.

  The speed control of the movable die plate 9 is feedback controlled based on the detection result of the second position sensor 91. For example, the speed of the movable die plate 9 is set to a relatively high speed in the initial stage of mold closing from the viewpoint of shortening the cycle time, and is relatively low in the final stage of mold closing to alleviate the impact at the time of mold contact. Set to

  When the target mold clamping force is obtained, the control device 41 controls the mold clamping side direction control valve 85 and the motor 35 so that the mold clamping force is maintained. For example, the control device 41 continues the control for setting the position of the mold clamping side direction control valve 85 to the position on the left side in FIG. 2 and the control for driving the motor 35, that is, the mold clamping cylinder device 11 by the pump 33. Continue to supply hydraulic fluid to and maintain the clamping force. Further, for example, the control device 41 once returns the mold clamping side direction control valve 85 to the neutral position, and the position of the mold clamping side direction control valve 85 is changed to the position shown in FIG. In other words, the supply of hydraulic fluid to the mold clamping cylinder device 11 by the pump 33 is continued intermittently to maintain the mold clamping force at the target value. The mold clamping force is maintained until the molten metal injected into the cavity Ca is solidified later.

  The mold clamping force is, for example, the amount of movement of the piston rod 17 of the mold clamping cylinder device 11, the pressure in the head side chamber Cy2 of the mold clamping cylinder device 11, or the extension amount of the tie bar in the case of a mold clamping device having a tie bar. It is detected by detecting an appropriate physical quantity. The control device 41 controls the mold clamping side direction control valve 85 and the motor 35 based on the detected mold clamping force.

(Low speed injection)
The control device 41 rotates the motor 35 and switches the injection side direction control valve 63 to the position on the right side of the sheet of FIG. As a result, the hydraulic fluid is supplied from the pump 33 to the head side chamber C2, the injection piston 27 and the piston rod 25 move forward, and the injection plunger 21 moves forward.

For example, the control device 41 controls the speed of the injection plunger 21 to a predetermined low speed (V _L ) based on the detection result of the first position sensor 90 (performs feedback control). The speed of the injection plunger 21 is controlled by controlling the rotational speed of the motor 35, for example. When the pump 33 is constituted by a variable displacement pump, the injection plunger 21 is controlled by controlling the discharge amount in one cycle of the pump 33 or by combining the control of the discharge amount and the rotation speed of the motor 35. The speed may be controlled.

  In controlling the rotational speed of the motor 35, for example, when the motor 35 is a DC motor, the torque and rotational speed of the motor 35 are controlled by controlling the voltage of the power supplied to the motor 35. When is an AC motor, the rotational speed of the motor 35 is controlled by controlling the frequency of the electric power supplied to the motor 35.

  When the motor 35 is an AC motor, the rotational speed of the motor 35 is proportional to the frequency of the electric power supplied to the motor 35 when the load torque is lower than the generated torque. Therefore, if the motor 35 is controlled so that the generated torque always exceeds the load torque, the rotation speed of the motor 35 can be made to follow the frequency of the electric power, and the operation of the injection plunger 21 can be made smooth.

  However, if the generated torque is excessively increased, the electric power supplied to the motor 35 is increased, and the life of the motor 35 is shortened. On the other hand, the load received by the injection plunger 21 varies from one die casting machine 1 to another mold 101 or from one molding cycle to another depending on the size and shape of the sleeve 19 and the cavity Ca.

  Therefore, the control device 41 controls the motor 35 so that the torque generated by the motor 35 is larger than the detected load torque of the motor 35 by a predetermined amount. For example, the control device 41 calculates the load that the injection cylinder device 23 receives from the injection plunger 21 based on the pressure detected by the third pressure sensor 94, and further calculates the load torque of the motor 35. A calculation formula or chart for calculating the load torque may be obtained based on theory or may be obtained by experiment. And the control apparatus 41 controls the electric current of the electric power supplied to the motor 35 from the servo driver 49 (inverter) so that the generated torque of the motor 35 may exceed the calculated load torque.

  Note that the current may be controlled as a result by controlling the voltage. Further, the control for causing the generated torque to exceed the load torque may be to calculate and control the target generated torque in the current molding cycle based on the load torque in the previous molding cycle, During one molding cycle, a new target generated torque may be calculated and controlled based on the current load torque. The generated torque may be set so that the entire torque in the rotation speed range that can be used is larger than the detected load torque, or newly generated based on the current load torque during one molding cycle. When setting the target generated torque, the generated torque at the current target rotational speed may be set to exceed the load torque.

(High speed injection)
When the position detected by the first position sensor 90 reaches a predetermined high-speed switching position (point D in FIG. 2), the control device 41 controls the supply side control valve 67 to switch the injection side direction control valve 63 to the neutral position. Control to open and control to open the injection-side flow rate control valve 71 are performed. As a result, the hydraulic fluid is supplied from the accumulator 37 to the head side chamber C2, and high-speed injection is performed. The control timing of these valves is appropriately set based on a test or the like so that the transition from the low speed injection to the high speed injection is performed smoothly. The speed of the injection plunger 21 is feedback controlled so as to follow a predetermined high speed (V _H ) with a predetermined ascending curve by flow control by the injection side flow control valve 71.

  The control device 41 rotates the motor 35 at the number of rotations necessary for maintaining the mold clamping force during the period from high speed injection to pressure increase. However, since the injection side direction control valve 63 is switched to the neutral position, the pump 33 and the injection cylinder device 23 are not directly linked to each other, and therefore the pump 33 has little influence on the injection speed and the like. .

(Deceleration)
When the injection plunger 21 reaches a predetermined deceleration start position (point L in FIG. 2), the control device 41 controls the injection side flow control valve so that the injection plunger 21 decelerates with a predetermined deceleration curve at a predetermined timing. 71 is controlled.

(Pressure increase)
When the injection plunger 21 reaches a predetermined pressure increase start position (point M in FIG. 2), the control device 41 performs control to fully open the injection side flow control valve 71 and control to open the pressure increase flow control valve 77. Do. As a result, hydraulic fluid is supplied from the accumulator 37 to the rear chamber C4, and the hydraulic fluid in the head chamber C2 is pressurized by the pressure-increasing action of the pressure-increasing piston 29. As a result, the molten metal in the cavity Ca is pressurized by the injection plunger 21. Is done. The control timing of the injection side flow rate control valve 71 and the pressure increase side flow rate control valve 77 is appropriately set based on a test or the like so that the transition to the pressure increase process is performed smoothly. The control device 41 controls the pressure increase side flow control valve 77 based on the detection value of the third pressure sensor 94 so that the injection pressure rises to a predetermined casting pressure _Pmax with a predetermined pressure increase curve.

  The supply control valve 67 is self-closed when the pressure in the head side chamber C2 is increased by the pressure-increasing piston 29 and becomes higher than the pressure in the accumulator 37. However, the pilot pressure may be introduced and closed.

(End of pressure holding)
In other words, after the predetermined time has elapsed from the time when the injection pressure reaches the casting pressure P _max , in other words, after the molten metal filled in the cavity Ca is solidified, the control device 41 controls the injection side flow control valve 71 and the pressure increase side flow control. Control to close the valve 77 is performed, and the pressure holding is finished. As will be described later, the injection-side flow rate control valve 71 is opened when the injection plunger follows the injection plunger.

(Open mold and follow plunger)
After a predetermined time has elapsed since the injection pressure reached the casting pressure P _max , in other words, after the molten metal filled in the cavity Ca has solidified, the control device 41 controls the mold clamping side direction control valve 85 as shown in FIG. Switch from the left position to the right position. Thereby, the pressure release of the head side chamber Cy2 is performed, and further, the hydraulic fluid from the pump 33 is supplied to the rod side chamber Cy1, and the mold opening is performed.

  Before switching the mold clamping side direction control valve 85, the amount of hydraulic fluid supplied to the head side chamber Cy2 is controlled to a predetermined value by controlling the rotation speed of the motor 35 and / or the discharge amount in one cycle of the pump 33. It is preferable to reduce gradually to (including 0). This is to alleviate the impact during depressurization. In particular, it is effective when the mold clamping device has a tie bar or when the force of the mold clamping cylinder is directly applied to the movable die plate.

  When the mold clamping side direction control valve 85 is switched, or when the pump 33 is stopped or decelerated before switching, the control device 41 synchronizes with the rotation start or speed increase of the pump 33. Control to open 71 is performed. Note that when the pilot pressure is introduced into the supply control valve 67 during the pressure increase, the introduction of the pilot pressure is also stopped. As a result, hydraulic fluid is supplied from the accumulator 37 to the head side chamber C2 of the injection cylinder device 23, and the injection plunger 21 moves following the movement of the movable die plate 9. The control device 41 opens the injection-side flow rate control valve 71 at a predetermined opening so that the speed of the injection plunger 21 is equal to or faster than the speed of the moving die plate 9.

(Retraction of injection plunger and end of mold opening)
When the control device 41 detects that the position of the injection plunger 21 based on the detection value of the first position sensor 90 or the second position sensor 91 has reached a predetermined stop position in the middle of mold opening, the injection-side flow rate control is performed. The valve 71 and the supply control valve 67 are closed. As a result, the supply of hydraulic fluid from the accumulator 37 to the injection cylinder device 23 is stopped. The stop position may be the physical advance limit of the injection piston 27.

  And the control apparatus 41 performs control which switches the injection | emission side direction control valve 63 to the position of the paper surface left side of FIG. Thereby, the hydraulic fluid sent out by the pump 33 is supplied to the rod side chamber C1 and the front side chamber C3, and the injection piston 27 (injection plunger 21) and the pressure increase piston 29 are moved backward. When the backward movement of the injection piston 27 and the pressure increasing piston 29 is completed, the control device 41 returns the injection side direction control valve 63 to the neutral position. The retraction of the injection plunger 21 may be started before the mold opening is finished or after the mold opening is finished.

  When the position of the movable die plate 9 detected by the second position sensor 91 reaches a predetermined mold opening position, the control device 41 returns the mold clamping side direction control valve 85 to the neutral position. Thereby, the supply of hydraulic fluid from the pump 33 to the mold clamping cylinder device 11 is stopped. The mold opening position may be a physical retreat limit of the mold clamping cylinder device 11.

(Accumulator pressure accumulation)
When the mold opening and the backward movement of the injection plunger 21 are completed, the control device 41 drives the motor 35 at a predetermined rotational speed. As a result, the hydraulic fluid is supplied from the pump 33 to the accumulator 37 to accumulate pressure in the accumulator 37. The control device 41 controls the motor 35 and the like so that the hydraulic fluid is sent to the accumulator 37 at a predetermined pressure and speed until the detection value of the second pressure sensor 93 reaches a predetermined set pressure.

  According to the first embodiment, the die casting machine 1 holds the fixed die plate 7 that holds the fixed die 103 and the movable die 105, and moves that can move in the mold opening / closing direction with respect to the fixed die plate 7. A die plate 9, a clamping cylinder device 11 that drives the movable die plate 9, a sleeve 19 that passes through the fixed die plate 7 and communicates with a cavity Ca formed in the fixed mold 103 and the movable mold 105; An injection plunger 21 that slides inside to extrude the molding material, an injection cylinder device 23 that drives the injection plunger 21, a pump 33 that can deliver hydraulic fluid, a motor 35 that drives the pump 33, and an accumulating hydraulic fluid The accumulator 37 that holds the pump in the state of being connected, the pump 33 and the accumulator 37 are connected, and the pump 33 and the clamping cylinder device 11 are connected. In addition, the accumulator 37 and the injection cylinder device 23 are connected to each other, and the hydraulic circuit 39 that controls the supply of hydraulic fluid to the mold clamping cylinder device 11 and the injection cylinder device 23, and the hydraulic circuit 39 and the motor 35 are controlled. The hydraulic pressure circuit 39 and the control device 41 accumulate the accumulator 37 by the pump 33 and supply the working fluid from the pump 33 to the mold clamping cylinder device 11 after the molding material in the cavity Ca is solidified. Then, the mold is opened, and in synchronism with the mold opening, the hydraulic fluid is supplied from the accumulator 37 to the injection cylinder device 23 and the biscuit Dt2 formed by the solidification of the molding material is pushed out by the injection plunger 21. Therefore, the power of the pump 33 is stored in the accumulator 37, and the clamping cylinder device 11 and the injection cylinder device are installed. 23 can be driven independently by a pump 33 and an accumulator 37, while the overall size of the hydraulic system is achieved, follow-up to the movable die plate 9 of the injection plunger 21 are properly made.

  The hydraulic circuit 39 and the control device 41 perform high-speed injection by supplying hydraulic fluid from the accumulator 37 to the injection cylinder device 23, and at least one of low-speed injection and pressure increase (low-speed injection in this embodiment) is performed by the pump 33. Therefore, the accumulator 37 is used not in all of the advancement process of the injection plunger 21 but only in a part thereof. As a result, supply of a large amount of hydraulic fluid required for high-speed injection in a short time is realized by the accumulator 37, and the accumulator 37 is downsized.

  The hydraulic circuit 39 is provided in the first flow path 51 that connects the pump 33 and the accumulator 37 and the first flow path 51, and allows the flow of hydraulic fluid from the pump 33 to the accumulator 37, while the accumulator 37 The second check valve 55 that prohibits the flow of hydraulic fluid from the pump 33 to the pump 33, and the hydraulic fluid from the position of the first flow path 51 closer to the pump 33 than the second check valve 55 to the clamping cylinder device 11 The mold clamping side direction control valve 85 that allows or prohibits the flow of the fluid and the supply control valve 67 that permits or prohibits the flow of the hydraulic fluid from the accumulator 37 to the injection cylinder device 23. The mold clamping side direction control valve 85 is controlled so as to prohibit the flow of hydraulic fluid from 33 to the mold clamping cylinder device 11, and the flow of hydraulic fluid from the accumulator 37 to the injection cylinder device 23 is prohibited. The control valve 67 is controlled, the motor 35 is controlled so as to drive the pump 33, the accumulator 37 is accumulated by the pump 33, and the flow of hydraulic fluid from the pump 33 to the mold clamping cylinder device 11 is allowed. The mold closing side direction control valve 85 is controlled, the motor 35 is controlled so as to drive the pump 33, the mold is opened, and the hydraulic fluid from the accumulator 37 to the injection cylinder device 23 is synchronized with the mold opening. Since the supply control valve 67 is controlled so as to allow the flow and the biscuit Dt2 is pushed out by the injection plunger 21, the accumulator 37 is pressure-accumulated, the mold is opened, and the biscuit Dt2 is pushed out by the injection plunger 21 with a simple configuration. Realized.

  The hydraulic circuit 39 includes an injection-side directional control valve 63 that can allow or prohibit the flow of hydraulic fluid from the position of the first flow path 51 closer to the pump 33 than the second check valve 55 to the injection cylinder device 23. The control device 41 controls the supply control valve 67 so as to prohibit the flow of hydraulic fluid from the accumulator 37 to the injection cylinder device 23, and allows the flow of hydraulic fluid from the pump 33 to the injection cylinder device 23. In this manner, the injection side direction control valve 63 is controlled to perform low-speed injection, the supply control valve 67 is controlled so as to allow the flow of hydraulic fluid from the accumulator 37 to the injection cylinder device 23, and the injection cylinder device from the pump 33. Since the injection side directional control valve 63 is controlled so as to prohibit the flow of the hydraulic fluid to 23 and high speed injection is performed, low speed injection by the pump 33 and high speed by the accumulator 37 are performed. Out, configuration is realized by a simple configuration.

(Second Embodiment)
FIG. 3 is a diagram showing a die casting machine 201 according to the second embodiment of the present invention.

  The second embodiment is different from the first embodiment in that when the hydraulic fluid is sent from the accumulator 37 to the injection cylinder device 23 and high-speed injection is performed, the injection cylinder device 23 is controlled by a meter-in circuit. Specifically, it is as follows.

  The hydraulic circuit 239 of the die casting machine 201 includes a supply control valve 267 provided in the fifth flow path 65 instead of the supply control valve 67 and the injection side flow control valve 71 of the first embodiment, and a sixth flow path. And a fourth check valve 271 provided at 69.

  The supply control valve 267 is configured by, for example, a flow rate control valve. More specifically, the supply control valve 267 is configured by, for example, a servo valve that is incorporated in a servo mechanism and can modulate the flow rate steplessly in accordance with an input signal. Yes. For example, the supply control valve 267 is configured to change the set value of the flow rate by sequentially operating an electromagnetic control mechanism and a hydraulic control mechanism.

  For example, the fourth check valve 271 is closed when the pilot pressure is introduced, and allows the flow from the injection cylinder device 23 side to the tank 43 side when the pilot pressure is not introduced, It is constituted by a pilot type check valve that prohibits the flow from the tank 43 side to the injection cylinder device 23 side.

  Therefore, by controlling the flow rate of the hydraulic fluid from the accumulator 37 to the head side chamber C2 by the supply control valve 267 in a state where the pilot pressure is not introduced to the fourth check valve 271, the injection piston of the injection cylinder device 23 is controlled. 27 forward speeds can be controlled.

  The operation of the die casting machine 201 is generally the same as that of the first embodiment. However, in place of the opening / closing control of the supply control valve 67 and the injection-side flow rate control valve 71 in the first embodiment, the opening / closing control of the supply control valve 267 and the fourth check valve 271 is performed, and at the time of high-speed injection The speed control of the injection cylinder device 23 is performed by controlling the opening degree of the supply control valve 267 instead of controlling the opening degree of the injection side flow rate control valve 71 in the first embodiment.

  According to the second embodiment described above, the same effect as that of the first embodiment, that is, the follow-up of the injection plunger 21 to the moving die plate 9 is appropriately performed while the entire hydraulic device is reduced in size. Effects such as

(Third embodiment)
FIG. 4 is a diagram showing a die casting machine 301 according to the third embodiment of the present invention.

  In the third embodiment, the pump 333 is constituted by a bidirectional (two-way) pump, and the hydraulic circuit 339 is suitable for driving the injection cylinder device 23 by the bidirectional pump. This is different from the first embodiment. Specifically, it is as follows.

  The pump 333 has two first ports 333a and second ports 333b, and the suction port and the discharge port are switched between the first port 333a and the second port 333b by switching the rotation direction. Similarly to the pump 33, the pump 333 may be a rotary pump, a plunger pump, a constant capacity pump, or a variable capacity pump. In addition, the 1st flow path 51 is connected to the 1st port 333a, for example.

  The hydraulic circuit 339 uses a twelfth channel 357 and a thirteenth channel 358 as a channel for connecting the pump 333 and the injection cylinder device 23, instead of the second channel 57 of the first embodiment. Have. The hydraulic circuit 339 replaces the tenth channel 83 of the first embodiment as a channel for connecting the pump 333 and the clamping cylinder device 11, and the fourteenth channel 383 and the fifteenth channel 384. have. The hydraulic circuit 339 includes an injection side direction control valve 363 and a mold clamping side direction control valve 385 instead of the injection side direction control valve 63 and the mold clamping side direction control valve 85 of the first embodiment. The injection side direction control valve 363 and the mold clamping side direction control valve 385 are not directly connected to the tank 43, and the eleventh flow path 84 of the first embodiment is omitted.

  The twelfth flow path 357 is connected to the first port 333a. The twelfth flow path 357 branches off from the first flow path 51 on the pump 333 side with respect to the second check valve 55 (a part of the first flow path 51 is shared). The thirteenth flow path 358 is connected to the second port 333b.

  The fourteenth flow path 383 is connected to the first port 333a. The fourteenth flow path 383 is branched from the twelfth flow path 357 on the pump 333 side with respect to the second check valve 55 (a part of the twelfth flow path 357 is shared). The fifteenth flow path 384 is connected to the second port 333b. Note that the fifteenth flow path 384 is branched from the thirteenth flow path 358 (part of the thirteenth flow path 358 is shared).

  The injection side direction control valve 363 is constituted by, for example, a four-port two-position switching valve, and switches the connection state between the first port 333a and the second port 333b and the rod-side chamber C1 and the head-side chamber C2. Specifically, it is as follows.

  The injection-side direction control valve 363 cuts off the connection between the pump 333 and the head-side chamber C2 and the rod-side chamber C1 at the right position (neutral position) of the two positions indicated by the two rectangular symbols. Thereby, the supply of the hydraulic fluid from the pump 333 to the head side chamber C2 and the rod side chamber C1 is prohibited.

  The injection side direction control valve 363 connects the first port 333a and the head side chamber C2 at the position on the left side of the drawing among two positions indicated by two rectangular symbols, and the second port 333b and the rod side chamber C1. Connect. At this time, the pump 333 sucks the working fluid in the rod side chamber C1 by rotating in one direction and sends it out to the head side chamber C2, and sucks the working fluid in the head side chamber C2 by rotating in the other direction. It can be delivered to the rod side chamber C1.

  The mold clamping side direction control valve 385 is constituted by, for example, a 4-port 2-position switching valve, and switches the connection state between the first port 333a and the second port 333b, the rod side chamber Cy1, and the head side chamber Cy2. Specifically, it is as follows.

  The mold clamping side direction control valve 385 cuts off the connection between the pump 333 and the head side chamber Cy2 and the rod side chamber Cy1 at the left side (neutral position) of the two positions indicated by two rectangular symbols. . Thereby, the supply of the hydraulic fluid from the pump 333 to the head side chamber Cy2 and the rod side chamber Cy1 is prohibited.

  The mold clamping side direction control valve 385 connects the first port 333a and the head side chamber Cy2 among the two positions indicated by two rectangular symbols, and connects the first port 333b and the rod side chamber Cy1. And connect. At this time, the pump 333 sucks the working fluid in the rod side chamber Cy1 by rotating in one direction and sends it to the head side chamber Cy2, and sucks the working fluid in the head side chamber Cy2 by rotating in the other direction. It can be delivered to the rod side chamber Cy1.

  Note that which of the rod side chamber (C1, Cy1) and the head side chamber (C2, Cy2) b is connected to which of the first port 333a and the second port 333b may be set as appropriate. The tightening cylinder device 11 and the injection cylinder device 23 may be different or the same. However, when the mold clamping cylinder device 11 and the injection cylinder device 23 are driven at the same time, the rod side chamber C1 or the head side chamber C2 and the rod side chamber Cy1 or the head side chamber Cy2 to which hydraulic fluid is supplied simultaneously are the same at the same time. Must be configured to be connectable to other ports. For example, in the present embodiment, as in the first embodiment, the hydraulic fluid is supplied to the head side chamber Cy2 of the mold clamping cylinder device 11 to continue the mold clamping while the hydraulic fluid is supplied to the head side chamber C2 of the injection cylinder device 23. Therefore, the head side chamber Cy2 and the head side chamber C2 are each provided with a flow path and a direction control valve so as to be connectable to the first port 333a.

  The mold clamping side direction control valve 385 and the injection side direction control valve 363 are configured such that their positions are switched by sequentially operating an electromagnetic control mechanism and a hydraulic control mechanism, for example. It is switched according to the signal.

  The hydraulic circuit 321 is preferably configured so that the hydraulic fluid is supplied to the pump 333 without excess or deficiency. For example, the cross-sectional area of the rod-side chamber C1 that can receive the hydraulic fluid is smaller than the cross-sectional area of the head-side chamber C2 that can receive the hydraulic fluid by the cross-sectional area of the piston rod 25. Accordingly, when the pump 333 sucks the hydraulic fluid from the rod side chamber C1 and discharges the hydraulic fluid to the head side chamber C2, the hydraulic fluid is insufficient, and the pump 333 sucks the hydraulic fluid from the head side chamber C2 and discharges the hydraulic fluid to the rod side chamber C1. When doing so, the hydraulic fluid becomes excessive.

  Therefore, the hydraulic circuit 339 has a self-supply valve circuit 340 for compensating for excess or deficiency of the hydraulic fluid in the pump 333. The self-supply valve circuit 340 includes a self-supply connection flow path 397 that connects the twelfth flow path 357 and the thirteenth flow path 358, and a self-supply tank flow path 398 that branches from the self-supply connection flow path 397 and is connected to the tank 43. And a first self-contained check valve 399A and a second self-contained check valve 399B provided in the self-contained connection flow path 397.

  The first self-contained check valve 399A is provided on the twelfth flow path 357 side of the self-sufficient connection flow path 397 from the position where the self-supply tank flow path 398 branches. The first self-contained check valve 399A is opened when the pilot pressure is introduced, and flows from the twelfth flow path 357 side to the self-sufficient tank flow path 398 side when the pilot pressure is not introduced. On the other hand, it is composed of a pilot type check valve that allows the flow from the self-contained tank channel 398 side to the twelfth channel 357 side. The first self-contained check valve 399A is provided such that the pressure of the working fluid in the thirteenth flow path 358 is introduced as a pilot pressure.

  The second self-contained check valve 399B is provided on the thirteenth flow path 358 side of the self-sufficient connection flow path 397 from the position where the self-supply tank flow path 398 branches. The second self-contained check valve 399B is opened when the pilot pressure is introduced, and flows from the thirteenth flow path 358 side to the self-sufficient tank flow path 398 side when the pilot pressure is not introduced. On the other hand, it is constituted by a pilot type check valve that allows the flow from the self-supply tank flow path 398 side to the 13th flow path 358 side. The first self-contained check valve 399A is provided such that the pressure of the working fluid in the twelfth flow path 357 is introduced as a pilot pressure.

  The operation of the self-supply valve circuit 340 is as follows.

  For example, when the pump 333 sucks the hydraulic fluid from the rod side chamber C1 and / or Cy1 and discharges the hydraulic fluid to the head side chamber C2 and / or Cy2, in other words, when the hydraulic fluid is insufficient, The hydraulic fluid in the tank 43 is replenished to the pump 333 via the self-supply tank flow path 398, the second self-supply check valve 397 B, and the 13th flow path 358. At this time, the flow of hydraulic fluid from the twelfth flow path 357 to the tank 43 is prohibited by the first self-contained check valve 399A.

  For example, when the pump 333 sucks the working fluid from the head side chamber C2 and / or Cy2, and discharges the working fluid to the rod side chamber C1 and / or Cy1, in other words, the working fluid becomes excessive. When the pressure of the hydraulic fluid in the thirteenth flow path 358 is introduced as a pilot pressure into the first self-checking check valve 399A, the first self-checking check valve 399A is opened, and excessive operation in the twelfth flow path 357 is performed. The liquid is discharged to the tank 43 via the first self-contained check valve 399A and the self-contained tank flow path 398. Note that the flow of hydraulic fluid from the thirteenth flow path 358 to the tank 43 is prohibited by the second self-contained check valve 399B.

  Further, for example, when the mold clamping side direction control valve 385 and the injection side direction control valve 363 are in the neutral position and the working fluid is supplied from the pump 333 to the accumulator 37 and the like, the working fluid in the tank 43 is self-supplied. The pump 333 is replenished via the tank flow path 398, the second self-contained check valve 397 </ b> B, and the 13th flow path 358. At this time, the flow of hydraulic fluid from the twelfth flow path 357 to the tank 43 is prohibited by the first self-contained check valve 399A.

  As can be understood from the above description, the check valve provided between the tank 43 and the second self-contained check valve 399B, that is, the flow path connected to the rod side chambers C1 and Cy1, is a pilot type. Not a check valve.

  Similar to the first embodiment, the hydraulic circuit 339 includes a first pressure sensor 92 that detects the pressure of the hydraulic fluid in the first flow path 51, in other words, the pressure of the hydraulic fluid in the first port 333a. ing. The hydraulic circuit 339 includes a fourth pressure sensor 492 that detects the pressure of the working fluid in the thirteenth flow path 358, in other words, the pressure of the working fluid in the second port 333b.

  The hydraulic circuit 339 does not have the cooler 72 of the first embodiment. In the third embodiment, since the hydraulic fluid pushed out by the injection piston 27 and the like is sucked into the pump 333, compared with the first embodiment, heat is generated when flowing through the valve and is discharged to the tank 43. This is because less hydraulic fluid is used.

  The operation of the die casting machine 301 is generally the same as the operation of the die casting machine 301 of the first embodiment. However, in the first embodiment, the supply destination of the hydraulic fluid from the pump 33 is switched between the rod side chamber C1 and the head side chamber C2 by switching the injection side direction control valve 63, and the mold clamping side direction control valve. When switching between the rod side chamber Cy1 and the head side chamber Cy2 is performed by switching 85, in the third embodiment, the supply destination of the hydraulic fluid from the pump 33 is switched to the rod side chamber C1 by switching the rotation direction of the motor 35. Between the rod side chamber C1 and the head side chamber C2.

  According to the above embodiment, the same effect as the first embodiment, that is, the follow-up of the injection plunger 21 to the moving die plate 9 is appropriately performed while the entire hydraulic device is downsized. An effect is produced.

(Fourth embodiment)
FIG. 5 is a diagram showing a die casting machine 401 according to the fourth embodiment of the present invention.

  In the fourth embodiment, similarly to the third embodiment, the pump 333 is a bidirectional (two-way) pump. However, when the hydraulic fluid is sent from the accumulator 37 to the injection cylinder device 23 to perform high-speed injection, the point that the injection cylinder device 23 is controlled by the meter-in circuit is the same as that of the third embodiment. Is different.

  That is, the fourth embodiment is a combination of the third embodiment and the second embodiment, and the hydraulic circuit 439 of the die casting machine 401 is controlled by the hydraulic circuit 339 of the third embodiment. Instead of the valve 67 and the injection-side flow rate control valve 71, a supply control valve 267 and a fourth check valve 271 of the second embodiment are provided.

  The operation of the die casting machine 401 is generally the same as that of the third embodiment. However, as the second embodiment is like the first embodiment, the supply control instead of the opening / closing control of the supply control valve 67 and the injection-side flow control valve 71 in the third embodiment. The opening / closing control of the valve 267 and the fourth check valve 271 is performed, and the speed control of the injection cylinder device 23 at the time of high speed injection is the control of the opening degree of the injection side flow control valve 71 in the third embodiment. Instead, it is performed by controlling the opening degree of the supply control valve 267.

  In the above embodiment, the fixed mold 103 is an example of the fixed mold of the present invention, the moving mold 105 is an example of the movable mold of the present invention, and the mold clamping cylinder device 11 is the moving cylinder apparatus of the present invention. The first flow path 51 is an example of the pump-accumulator flow path of the present invention, and the mold clamping side direction control valve 85 is an example of the movement side direction control valve of the present invention.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The molding machine is not limited to a die casting machine. In other words, the molding material is not limited to a metal material. For example, the molding machine may be an injection molding machine that injects a resin as a molding material. The mold clamping device is not limited to a direct pressure type, and may be a toggle type, or a composite type in which a drive mechanism for opening and closing the mold and a drive mechanism for performing mold clamping are separately provided. There may be. The hydraulic fluid is not limited to oil and may be water, for example.

  The hydraulic circuit may not be configured to be able to supply hydraulic fluid directly from the pump to the injection cylinder device. For example, the injection cylinder device may be driven only by the accumulator. However, as in the embodiment, when the hydraulic fluid is supplied to the injection cylinder device by the pump in a part of the advancement process of the injection plunger, the accumulator can be reduced in size by effectively using the pump.

  The hydraulic circuit and the control device may be configured to increase pressure by a pump. For example, in FIG. 1, a valve (for example, when pilot pressure is introduced, which is allowed or prohibited from flowing to the accumulator 37 side of the first flow path 51 from the position where the seventh flow path 75 branches, is closed, When the pilot pressure is not introduced, a pilot check valve that allows the flow from the pump 33 to the accumulator 37 but prohibits the flow from the accumulator 37 to the pump 33 is provided. The pressure increase side flow control valve 77 is closed, and the pilot pressure is not introduced into the check valve. When the pressure is increased, the pressure increase side flow control valve 77 is opened, and the pilot pressure is introduced into the check valve and closed. A hydraulic circuit and a control device may be configured to drive the pump 33. In this case, since the pressure at the time of pressure increase can be controlled by controlling the rotation speed of the pump 33 and / or the discharge amount per cycle of the pump, the pressure increase side flow control valve 77 does not have a flow control function. It may be a valve.

  The hydraulic circuit and the control device may be configured to perform low-speed injection and high-speed injection using an accumulator and increase pressure using a pump. Even in this case, it is possible to reduce the burden on the accumulator by using the pump in the advancement process of the injection plunger. However, since the cylinder system requires a relatively large amount of hydraulic fluid for low-speed injection, it is more effective to reduce the burden on the accumulator when low-speed injection is performed with a pump, and the accumulator pressure drops before high-speed injection. Occurrence is also suppressed.

  The specific configuration of the hydraulic circuit and the specific control by the control device are various in addition to the first to fourth embodiments. For example, by providing a directional control valve that switches the supply destination of the hydraulic fluid from the pump between the accumulator and the cylinder device, it is possible to store the accumulator pressure and drive the cylinder device by the pump. is there.

  The injection cylinder device is not limited to the pressure increasing type, and may be a single acting type. Further, the pressure increasing type cylinder device is not limited to a direct connection type in which a large diameter cylinder tube is coaxially directly connected to a small diameter cylinder tube. For example, a small diameter cylinder tube and a cylinder tube for pressure increase May be of a separated type connected by a flow path formed by a hose or the like.

  The pump may not continue supplying the hydraulic fluid to the mold clamping cylinder device after the mold clamping force is obtained. For example, after the mold clamping, the mold clamping force can be maintained by providing a stopper that holds the movable die plate, the tie bar, or the piston of the mold clamping cylinder device at a fixed position.

  The control of the motor at the time of low-speed injection may be feedback control that corrects the speed and / or torque based only on the detected value of the speed of the injection plunger, not on the detected value of the load.

The figure which shows the structure of the die-casting machine of the 1st Embodiment of this invention. The figure which shows the time-dependent change of the injection speed and injection pressure in the die-casting machine of FIG. The figure which shows the structure of the die-casting machine of the 2nd Embodiment of this invention. The figure which shows the structure of the die-casting machine of the 3rd Embodiment of this invention. The figure which shows the structure of the die-casting machine of the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Die casting machine (molding machine), 7 ... Fixed die plate, 9 ... Moving die plate, 11 ... Clamping cylinder apparatus (moving cylinder apparatus), 19 ... Sleeve, 21 ... Injection plunger, 23 ... Injection cylinder apparatus, 33 ... Pump, 35 ... motor, 37 ... accumulator, 39 ... hydraulic circuit, 41 ... control device, 103 ... fixed mold (fixed mold), 105 ... moving mold (movable mold), Ca ... cavity.

Claims (4)

A fixed die plate that holds the fixed mold;
A movable die plate that holds the movable mold and is movable in the mold opening and closing direction with respect to the fixed die plate;
A moving cylinder device for driving the moving die plate;
A sleeve that passes through the fixed die plate and leads to a cavity formed in the fixed mold and the movable mold;
An injection plunger that slides within the sleeve to extrude the molding material;
An injection cylinder device for driving the injection plunger;
A pump capable of delivering hydraulic fluid;
A motor for driving the pump;
An accumulator that holds the hydraulic fluid in an accumulated state;
Connecting the pump and the accumulator, connecting the pump and the moving cylinder device, connecting the accumulator and the injection cylinder device, and supplying hydraulic fluid to the moving cylinder device and the injection cylinder device A hydraulic circuit for controlling
A control device for controlling the hydraulic circuit and the motor;
Have
The hydraulic circuit and the control device accumulate the accumulator by the pump, and after solidifying the molding material of the cavity, supply hydraulic fluid from the pump to the moving cylinder device to perform mold opening, and the mold opening The molding machine is configured to supply hydraulic fluid from the accumulator to the injection cylinder device in synchronism with the above and to push out the biscuits formed by the solidification of the molding material by the injection plunger. The hydraulic circuit and the control device perform high-speed injection by supplying hydraulic fluid from the accumulator to the cylinder device, and perform at least one of low-speed injection and pressure increase from the pump to the injection cylinder device. The molding machine according to claim 1, wherein the molding machine is configured to perform the above-described supply. The hydraulic circuit is
A pump-accumulator flow path connecting the pump and the accumulator;
A check valve provided in the pump-accumulator flow path, which allows the flow of hydraulic fluid from the pump to the accumulator while prohibiting the flow of hydraulic fluid from the accumulator to the pump;
A moving-side direction control valve that allows or prohibits the flow of hydraulic fluid from the position on the pump side of the pump-accumulator flow path to the moving cylinder device with respect to the check valve;
A supply control valve that allows or prohibits the flow of hydraulic fluid from the accumulator to the injection cylinder device;
Have
The controller is
The supply control valve controls the moving side direction control valve to prohibit the flow of hydraulic fluid from the pump to the moving cylinder device, and prohibits the flow of hydraulic fluid from the accumulator to the injection cylinder device And controlling the motor to drive the pump, accumulating the accumulator with the pump,
Control the moving side direction control valve to allow the flow of hydraulic fluid from the pump to the moving cylinder device, control the motor to drive the pump, perform mold opening,
3. The biscuit is pushed out by the injection plunger by controlling the supply control valve so as to allow a flow of hydraulic fluid from the accumulator to the injection cylinder device in synchronization with the mold opening. Molding machine. The hydraulic circuit has an injection-side directional control valve capable of allowing or prohibiting the flow of hydraulic fluid from the position on the pump side of the pump-accumulator flow path to the injection cylinder device with respect to the check valve. ,
The controller is
The supply control valve is controlled to prohibit the flow of hydraulic fluid from the accumulator to the injection cylinder device, and the injection side direction control valve is allowed to allow the flow of hydraulic fluid from the pump to the injection cylinder device. Control, do low speed injection,
The supply control valve is controlled to allow the flow of hydraulic fluid from the accumulator to the injection cylinder device, and the injection side direction control valve is controlled to prohibit the flow of hydraulic fluid from the pump to the injection cylinder device. The molding machine according to claim 3, wherein the injection is performed at a high speed.

Images