JP4782250B1 - Injection machine for molding machine - Google Patents

Abstract

An injection device for a molding machine that can reduce the load on a moving rod is provided.
An injection device includes an injection cylinder device that drives a plunger. The injection cylinder device 7 has an injection piston 23 whose front portion is connected to the plunger 5, and a cylinder tube 21 that slidably accommodates a rear portion of the injection piston 23. The inside of the cylinder tube 21 is a piston portion 23b. Thus, a front rod side chamber 21r and a rear head side chamber 21h are partitioned. The injection device 1 includes a hydraulic device 9 that can supply hydraulic fluid to the injection cylinder device 7, a moving rod 11 that can push the injection piston 23 forward, and a drive device 13 that can drive the moving rod 11. And have. The moving rod 11 is inserted so as to be movable in the axial direction with respect to the injection piston 23, and the distal end portion 11b is isolated from the head side chamber 21h.
[Selection] Figure 1

Description

  The present invention relates to an injection device for a molding machine. The molding machine is, for example, a die casting machine or an injection molding machine.

  A so-called hybrid injection device is known in which a plunger for extruding a molding material is driven by a combination of a hydraulic device and an electric motor (for example, Patent Document 1). Specifically, in Patent Document 1, an injection cylinder device that drives a plunger, a moving rod that is inserted behind a cylinder tube of the injection cylinder device and can push the injection piston of the injection cylinder device forward, and the movement An injection device having an electric motor for driving a rod is disclosed.

  In the low-speed injection, the injection device of Patent Document 1 advances the moving rod with an electric motor and pushes out an injection piston with the moving rod. Further, the injection device supplies hydraulic fluid from the accumulator to the back of the injection piston while continuing to drive the electric motor at high speed injection and pressure increase. That is, the injection piston is advanced by the high-pressure hydraulic fluid from the accumulator, and the hydraulic fluid is pressurized by the moving rod.

JP 2008-73708 A

  In the technique disclosed in Patent Document 1, the high pressure of the hydraulic fluid acts as a force for retracting the moving rod at the tip of the moving rod in high-speed injection and pressure increase. As a result, for example, the electric motor must be enlarged.

  The objective of this invention is providing the injection apparatus of the molding machine which can reduce the load of a moving rod.

  An injection device for a molding machine according to an aspect of the present invention includes a plunger that pushes a molding material into a cavity, an injection piston having a front portion connected to the plunger, and a cylinder that slidably accommodates a rear portion of the injection piston. An injection cylinder device in which the inside of the cylinder tube is partitioned into a front rod side chamber and a rear head side chamber by the rear portion of the injection piston, and a liquid capable of supplying hydraulic fluid to the head side chamber A pressure device, a moving rod that is inserted behind the cylinder tube and can push the injection piston forward, and a drive device that can drive the moving rod in the axial direction with respect to the cylinder tube. The moving rod is inserted so as to be movable in the axial direction with respect to the injection piston, and the tip is isolated from the head side chamber. .

  Preferably, the drive device includes a rotary electric motor and a transmission mechanism that converts the rotation of the electric motor into a translational motion and transmits the translation motion to the moving rod.

  Preferably, in low-speed injection, a driving force is applied from the driving device to the injection piston, and from the hydraulic device, no driving force is applied to the injection piston. In high-speed injection and pressure increase, the driving force is applied. The apparatus further includes a control device for controlling the driving device and the hydraulic pressure device such that the driving force is not applied to the injection piston from the device and the driving force is applied to the injection piston from the hydraulic pressure device.

  Preferably, the moving rod has an engaging portion that engages the injection piston from the front to the rear, and the movable rod engaged with the injection piston is moved backward to retract the plunger after molding. A control device is provided for controlling the driving device so as to move backward.

  Preferably, the hydraulic device has an accumulator capable of supplying hydraulic fluid to the head side chamber during high-speed injection, and the control device discharges hydraulic fluid from the head side chamber as the injection piston moves backward. Is supplied to the accumulator, and the driving device and the hydraulic device are controlled so as to fill the accumulator.

  Preferably, the hydraulic device has a run-around circuit that communicates the rod side chamber and the head side chamber.

  Preferably, the hydraulic device has a flow rate control valve capable of adjusting a flow rate of the hydraulic fluid discharged from the rod side chamber.

  Preferably, the plurality of driving devices are provided in parallel to the moving rod and at rotationally symmetric positions with respect to the moving rod.

  According to the present invention, the load on the moving rod can be reduced.

The schematic diagram which shows the structure of the principal part of the injection device of the die-casting machine which concerns on the 1st Embodiment of this invention. The figure explaining operation | movement of the injection device of FIG. The schematic diagram which shows the structure of the principal part of the injection apparatus of the die-casting machine which concerns on the 2nd Embodiment of this invention. The figure explaining operation | movement of the injection device of FIG. The schematic diagram which shows the structure of the principal part of the injection device of the die-casting machine which concerns on the 3rd Embodiment of this invention. The figure explaining operation | movement of the injection apparatus of FIG. The schematic diagram which shows the structure of the principal part of the injection apparatus of the die-casting machine which concerns on the 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment to be described, the same or similar configuration as the configuration of the already described embodiment may be denoted by the same reference numeral as that of the already described embodiment, and the description may be omitted.

<First Embodiment>
(Configuration of injection device)
FIG. 1 is a diagram illustrating a configuration of a main part of an injection device 1 of a die casting machine DC1 according to a first embodiment of the present invention.

  The injection apparatus 1 is an apparatus that injects and fills molten metal (a molten metal material) into a cavity 105 formed by a stationary mold 101 and a movable mold 103 held by a mold clamping device (not shown).

  The injection device 1 includes a sleeve 3 that communicates with the cavity 105, a plunger 5 that pushes the molten metal into the cavity 105 in the sleeve 3, an injection cylinder device 7 that drives the plunger 5, and an injection cylinder device 7 that is hydraulic fluid (for example, oil). And a hydraulic device 9 for driving by supply.

  Further, the injection device 1 has a moving rod 11 and a driving device 13 for driving the moving rod 11 in order to drive the injection cylinder device 7 by a driving source different from the hydraulic device 9. The drive device 13 includes, for example, a rotary injection motor 15 and a transmission mechanism 17 that converts the rotation of the injection motor 15 into a translational motion and transmits the translation motion to the moving rod 11. Furthermore, the injection device 1 has a control device 19 that controls the hydraulic device 9 and the drive device 13.

  Details will be described below in the order of the above enumerations.

  The sleeve 3 is provided so as to be inserted through the fixed mold 101, for example. The plunger 5 has a plunger tip 5a that slides on the sleeve 3, and a plunger rod 5b fixed to the plunger tip 5a.

  When the molten metal is supplied into the sleeve 3 from the hot water supply port 3 a formed in the sleeve 3, the plunger tip 5 a slides (moves forward) in the sleeve 3 toward the cavity 105, so that the molten metal enters the cavity 105. Injection and filling.

(Configuration of hydraulic drive system: injection cylinder device 7, hydraulic device 9, etc.)
The injection cylinder device 7 is constituted by, for example, a pressure increasing type injection cylinder device, and includes a cylinder tube 21, an injection piston 23 and a pressure increasing piston 25 slidable inside the cylinder tube 21.

  The injection cylinder device 7 is disposed coaxially with the plunger 5, the injection piston 23 is connected to the plunger 5 via a joint 27, and the cylinder tube 21 is fixed to a mold clamping device (not shown) or the like. Is provided. Accordingly, the plunger 5 moves forward or backward in the sleeve 3 by the movement of the injection piston 23 relative to the cylinder tube 21.

  The cylinder tube 21 has an injection cylinder part 21a and a pressure-increasing cylinder part 21b connected to the rear of the injection cylinder part 21a. The injection cylinder part 21a and the pressure increasing cylinder part 21b are, for example, cylindrical bodies having a circular cross section.

  The injection piston 23 has a rod portion 23a connected to the plunger 5 via a joint 27, and a piston portion 23b that slides on the injection cylinder portion 21a. The rod portion 23a includes a small diameter rod portion 23aa connected to the plunger 5 and a large diameter rod portion 23ab having a larger diameter than the small diameter rod portion 23aa.

  The cross-sectional shapes of the small diameter rod portion 23aa, the large diameter rod portion 23ab, and the piston portion 23b are, for example, circular. The large-diameter rod portion 23ab has a diameter smaller than that of the injection cylinder portion 21a and protrudes from the front of the injection cylinder portion 21a to the outside of the injection cylinder portion 21a.

  The inside of the injection cylinder portion 21a is partitioned by a piston portion 23b into a rod side chamber 21r on the side from which the rod portion 23a extends and a head side chamber 21h on the opposite side. By supplying the working fluid to the head side chamber 21h, the injection piston 23 can be moved forward (moved toward the plunger 5).

  Although not particularly illustrated, the seal between the rod portion 23a and the opening in front of the injection cylinder portion 21a and the seal between the piston portion 23b and the injection cylinder portion 21a are made using appropriate members such as V packing. May be done.

  The pressure-increasing cylinder part 21b is connected to the head side chamber 21h side of the injection cylinder part 21a and has a larger diameter than the injection cylinder part 21a.

  The pressure increasing piston 25 includes a small diameter piston portion 25a that can slide inside the injection cylinder portion 21a (head side chamber 21h), a large diameter piston portion 25b that can slide inside the pressure increasing cylinder portion 21b, and a pressure increasing cylinder. And a rear portion 25c extending rearward from the portion 21b.

  The inside of the pressure increasing cylinder portion 21b is partitioned by a large-diameter piston portion 25b into a front chamber 21f on the injection cylinder portion 21a side and a rear chamber 21g on the opposite side. The pressure receiving area in the rear chamber 21g of the large diameter piston portion 25b is larger than the pressure receiving area in the front chamber 21f of the small diameter piston portion 25a.

  Therefore, when the front chamber 21f is depressurized, the pressure increasing piston 25 is caused by the difference between the pressure receiving area in the head side chamber 21h of the small diameter piston portion 25a and the pressure receiving area in the rear chamber 21g of the large diameter piston portion 25b. A pressure higher than the pressure received from the hydraulic fluid in the rear chamber 21g can be applied to the hydraulic fluid in the head chamber 21h. That is, the injection cylinder device 7 has a pressure increasing function.

  Although not particularly illustrated, a seal between the small-diameter piston portion 25a and the injection cylinder portion 21a, a seal between the large-diameter piston portion 25b and the booster cylinder portion 21b, and the rear portion of the rear portion 25c and the booster cylinder portion 21b. Sealing between the two openings may be performed using an appropriate member such as a V packing.

  The hydraulic device 9 includes a tank 29 for storing hydraulic fluid, an accumulator 31 for supplying hydraulic fluid to the injection cylinder device 7, a pump 33 for filling the accumulator 31, and a filling electric motor for driving the pump 33. 35.

  The tank 29 is an open tank, for example, and holds the working fluid under atmospheric pressure. The tank 29 receives the hydraulic fluid discharged from the injection cylinder device 7 and supplies the hydraulic fluid to the accumulator 31 via the pump 33.

  The accumulator 31 may be constituted by an accumulator of an appropriate type such as a weight type, a spring type, a gas pressure type (including a pneumatic type), a cylinder type, or a prada type. For example, the accumulator 31 is a gas pressure type, cylinder type, or prada type accumulator, and the gas (for example, air or nitrogen) held in the accumulator 31 is compressed to be compressed, and the accumulator 31 is operated by the accumulated pressure. Supply liquid.

  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. Further, the pump 33 may be a fixed capacity pump or a variable capacity pump in which the discharge amount in one cycle of movement of the rotor or piston may be variable. The pump 33 is sufficient if it can discharge the hydraulic fluid in one direction, but the structure may be the same as that of the bidirectional (two-way) pump.

  The charging motor 35 may be a DC motor or an AC motor. Further, the filling motor 35 may be constituted by an appropriate motor such as an induction motor or a synchronous motor. The filling motor 35 is configured as a servo motor, for example, and constitutes a servo mechanism together with an encoder 37 that detects the rotation of the filling motor 35 and a servo driver (servo amplifier) 39 that supplies power to the filling motor 35. is doing.

  In the description of the operation to be described later, when the charging motor 35 is stopped, the charging motor 35 may be in a torque-free state or may be controlled to stop at a certain position. The brake may be used, and the brake may be used. An appropriate stopping method may be selected according to the specific configuration of the injection device and the situation in which the charging motor 35 is stopped.

  The hydraulic device 9 includes a plurality of flow paths that connect the injection cylinder device 7, the tank 29, the accumulator 31, and the pump 33, and a plurality of valves that control the flow of hydraulic fluid in the plurality of flow paths. Yes. The plurality of flow paths are constituted by, for example, a steel pipe, a flexible hose, or a metal block. Specifically, the hydraulic device 9 has, for example, a flow path and a valve described below.

  The hydraulic device 9 includes a first flow path 41 that connects the accumulator 31 and the head side chamber 21h, and a second flow path 43 that connects the rod side chamber 21r and the tank 29.

  Therefore, the injection apparatus 1 can advance the injection piston 23 by supplying the hydraulic fluid from the accumulator 31 to the head side chamber 21h via the first flow path 41. At this time, the hydraulic fluid pushed out from the rod side chamber 21r as the injection piston 23 moves forward is discharged to the tank 29 via the second flow path 43.

  The hydraulic device 9 has a third flow path 45 that connects the accumulator 31 and the rear chamber 21g, and a fourth flow path 47 that connects the front chamber 21f and the rod side chamber 21r. A part of the third flow path 45 on the accumulator 31 side is shared with a part of the first flow path 41 on the accumulator 31 side. However, these need not be shared.

  The front chamber 21f is connected to the tank 29 via the fourth flow path 47, the rod side chamber 21r, and the second flow path 43, and can be depressurized. Instead of the fourth flow path 47, a flow path that directly connects the front chamber 21f and the tank 29 may be provided.

  The injection device 1 supplies the hydraulic fluid from the accumulator 31 to the rear chamber 21g via the third flow path 45, and performs pressure relief of the front chamber 21f using the fourth flow path 47, thereby increasing the above-described increase. A pressure higher than the pressure of the accumulator 31 can be applied to the head side chamber 21h using the pressure increasing action of the pressure piston 25.

  The hydraulic device 9 has a fifth flow path 49 that connects the discharge port of the pump 33 and the accumulator 31. A part of the fifth channel 49 on the accumulator 31 side is shared with a part of the first channel 41 on the accumulator 31 side. However, these need not be shared.

  The injection device 1 can accumulate pressure in the accumulator 31 by supplying hydraulic fluid from the pump 33 to the accumulator 31 via the fifth flow path 49.

  The hydraulic device 9 has a sixth flow path 51 that connects the head side chamber 21 h and the tank 29. A part of the sixth flow path 51 on the head side chamber 21h side is shared with a part of the first flow path 41 on the head side chamber 21h side, and a part of the tank 29 side is on the tank 29 side of the second flow path 43. Shared with some of the. However, these need not be shared.

  The injection device 1 can discharge the hydraulic fluid pushed out from the head side chamber 21 h as the injection piston 23 moves backward to the tank 29 via the sixth flow path 51.

  The hydraulic device 9 has a seventh flow path 53 that connects the rear chamber 21 g and the tank 29. The seventh flow path 53 has a part on the rear chamber 21g side shared with a part on the rear flow path 21g side of the third flow path 45, and a part on the tank 29 side is a part of the second flow path 43 on the tank 29 side. The intermediate part of these shared parts is shared with the intermediate part of the sixth flow path 51. However, these need not be shared.

  The injection device 1 can discharge the hydraulic fluid pushed out from the rear chamber 21 g as the pressure-increasing piston 25 moves backward to the tank 29 through the seventh flow path 53.

  The hydraulic device 9 has an eighth flow path 55 that connects the pump 33 and the rod side chamber 21r. The eighth flow channel 55 has a part on the rod side chamber 21r side shared with a part on the rod side chamber 21r side of the second flow channel 43, and a part on the pump 33 side on the pump 33 side of the fifth flow channel 49. Shared with some of the. However, these need not be shared.

  The injection device 1 can retract the injection piston 23 by supplying hydraulic fluid from the pump 33 to the rod side chamber 21r via the eighth flow path 55. The hydraulic fluid supplied to the rod side chamber 21r is supplied to the front side chamber 21f via the fourth flow path 47 and contributes to the retreat of the pressure increasing piston 25.

  The hydraulic device 9 has a servo valve 57 provided in the first flow path 41. The servo valve 57 can adjust the flow rate steplessly by opening with an opening degree corresponding to the input voltage. The servo valve 57 can output a signal corresponding to the degree of opening, and constitutes a servo mechanism by performing feedback control based on the signal. The servo valve 57 is constituted by, for example, a flow rate control valve with pressure compensation. The servo valve 57 can control the operation (speed) of the injection cylinder device 7 by controlling the flow rate of the hydraulic fluid supplied to the head side chamber 21h, and constitutes a so-called meter-in circuit.

  The hydraulic device 9 has a first check valve VLA to a sixth check valve VLF. Among these, the first check valve VLA to the fifth check valve VLE are controlled by introducing pilot pressure. As the pilot pressure, for example, the pressure of the accumulator 31 is used via a hydraulic circuit (not shown). The arrangement and function of the first check valve VLA to the sixth check valve VLF are specifically as follows.

  The first check valve VLA is provided in the first flow path 41. The first check valve VLA allows the flow of hydraulic fluid from the accumulator 31 side to the head side chamber 21h side and prohibits the flow in the opposite direction when the pilot pressure is not introduced. The first check valve VLA allows both flows when the pilot pressure for opening is introduced and prohibits both flows when the pilot pressure for closing is introduced.

  The second check valve VLB is provided in the second flow path 43. When the pilot pressure is not introduced, the second check valve VLB allows the flow of the hydraulic fluid from the rod side chamber 21r side to the tank 29 side and prohibits the flow on the opposite side. Further, the second check valve VLB prohibits (closes) both flows when the pilot pressure is introduced.

  The third check valve VLC is provided in the third flow path 45. When the pilot pressure is not introduced, the third check valve VLC allows the hydraulic fluid to flow from the accumulator 31 side to the rear chamber 21g side, and prohibits the flow in the opposite direction. The third check valve VLC allows both flows when the pilot pressure for opening is introduced, and prohibits both flows when the pilot pressure for closing is introduced.

  The fourth check valve VLD is provided in the fifth flow path 49. The fourth check valve VLD allows the flow of hydraulic fluid from the pump 33 side to the accumulator 31 side and prohibits the flow in the opposite direction when the pilot pressure is not introduced. Further, the fourth check valve VLD prohibits (closes) both flows when the pilot pressure is introduced.

  The fifth check valve VLE is provided in the sixth flow path 51 (seventh flow path 53). The fifth check valve VLE allows the flow of hydraulic fluid from the tank 29 side to the head side chamber 21h (rear side chamber 21g) side and prohibits the flow in the opposite direction when the pilot pressure is not introduced. Further, the fifth check valve VLE allows (opens) both flows when the pilot pressure is introduced.

  The sixth check valve VLF is provided in a shared part of the fifth flow path 49 and the eighth flow path 55. The sixth check valve VLF allows the flow of hydraulic fluid from the pump 33 to the accumulator 31 and the rod side chamber 21r side, and prohibits the flow on the opposite side.

  In addition to the above, the hydraulic device 9 may have a flow path and a control valve for sending the hydraulic fluid of the pump 33 to an appropriate device such as a cylinder device for the core.

(Configuration of electric drive system: moving rod 11, transmission mechanism 17, injection motor 15, etc.)
The moving rod 11 is inserted behind the cylinder tube 21 so as to be able to push the injection piston 23 forward. Specifically, it is as follows.

  The moving rod 11 has a rod main body 11a extending with a constant cross-sectional shape, and a tip end portion 11b provided at the tip of the rod main body 11a. The cross-sectional shape of the rod main body 11a and the front-end | tip part 11b is circular, for example. The tip portion 11b is formed to have a larger diameter than the rod main body 11a, and the outer peripheral surface protrudes outward from the outer peripheral surface of the rod main body 11a (a flange is provided). The distal end surface of the distal end portion 11b is, for example, a flat surface.

  The pressure increasing piston 25 is formed with a through hole 25h through which the rod body 11a is slidably inserted. The through hole 25h has an enlarged diameter on the center side in the penetrating direction in order to reduce sliding resistance with respect to the rod body 11a, for example. In addition, this expanded diameter part is filled with lubricating oil (hydraulic fluid), for example.

  The injection piston 23 is formed with a slide hole 23e through which the rod body 11a is slidably inserted and a housing portion 23f capable of housing the distal end portion 11b of the moving rod 11.

  The inner front end face of the accommodating portion 23f is a contacted portion 23g with which the tip end portion 11b can contact. The contacted portion 23g is a flat surface, for example. The accommodating portion 23f is formed to have a larger diameter than the sliding hole 23e, and the inner rear end surface of the accommodating portion 23f is an engaged portion 23k that engages the front end portion 11b from the front to the rear. The engaged portion 23k is, for example, a flat surface.

  The moving rod 11 can advance the injection piston 23 by moving the tip 11b abutting on the contacted portion 23g of the injection piston 23 and moving forward. Further, the moving rod 11 can retract the injection piston 23 by retracting the distal end portion 11b against the engaged portion 23k of the injection piston 23.

  Note that the movable distance L of the distal end portion 11b relative to the housing portion 23f from the position where the distal end portion 11b abuts against the abutted portion 23g to the position where the distal end portion 11b abuts against the engaged portion 23k is a high-speed injection described later. It is set larger than the stroke of the injection piston 23.

  The accommodating portion 23f is formed to have a diameter larger than that of the distal end portion 11b, and a gap is formed between the inner peripheral surface of the accommodating portion 23f and the outer peripheral surface of the distal end portion 11b. Accordingly, the tip end portion 11b moves in the contact portion 23f in a non-contact manner.

  The housing portion 23f is isolated from the head side chamber 21h by sealing the sliding hole 23e and the rod body 11a. Accordingly, the pressure of the hydraulic fluid in the head side chamber 21h does not act on the tip portion 11b.

  The accommodating portion 23f communicates with the rod side chamber 21r via an opening (not shown) formed in the large diameter rod portion 23ab, for example. Therefore, the inside of the accommodating portion 23f is filled with the working fluid, and the pressure is equal to that of the rod side chamber 21r. Further, the hydraulic fluid in the housing portion 23f is discharged into the rod side chamber 21r or replenished from the rod side chamber 21r as the moving rod 11 is inserted into and pulled out from the housing portion 23f. Note that an opening (not shown) that connects the housing portion 23f and the rod side chamber 21r is formed in a portion of the injection piston 23 that is located in the rod side chamber 21r even when the injection piston 23 is positioned at the forward limit.

  The injection motor 15 is a rotary motor, and although not particularly illustrated, 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 is rotatable with respect to the stator And have. The injection motor 15 may be a DC motor or an AC motor, or may be an induction motor or a synchronous motor, like the charging motor 35. The injection motor 15 is configured as a servo motor, for example, and constitutes a servo mechanism together with an encoder 59 that detects the rotation of the injection motor 15 and a servo driver 61 that supplies power to the injection motor 15.

  In the description of the operation to be described later, when the injection motor 15 is stopped, an appropriate stop method may be selected according to the specific configuration of the injection device and the situation in which the injection motor 15 is stopped. Is the same as the electric motor 35 for filling.

  The transmission mechanism 17 includes, for example, a screw mechanism, and includes a screw shaft 63 fixed to the moving rod 11 and a nut 65 that is screwed to the screw shaft 63 and is rotationally driven by the injection motor 15. .

  The screw shaft 63 extends concentrically behind the moving rod 11 from the moving rod 11. The moving rod 11 and the screw shaft 63 may be formed integrally, or may be formed separately and fixed to each other. Although not particularly illustrated, the rotation of the screw shaft 63 is restricted by an appropriate method (for example, formation of a spline).

  The nut 65 is fixed (integrated) to, for example, a rotor (not shown) of the injection motor 15. The injection motor 15 is disposed concentrically with the screw shaft 63 in a state where the nut 65 is screwed onto the screw shaft 63.

  When the nut 65 is rotationally driven by the injection motor 15, a driving force in the axial direction is applied to the screw shaft 63. Thereby, the screw shaft 63 moves in the axial direction, and the moving rod 11 moves forward or backward.

  The driving device 13 may be provided as a part of the injection cylinder device 7. In other words, the injection motor 15 may be provided as a built-in motor.

(Control system)
The control device 19 includes, for example, a CPU 67, a memory 69 such as a ROM or a RAM, an input circuit 71, and an output circuit 73. The CPU 67 executes a program stored in the memory 69, and outputs a control signal for controlling each unit via the output circuit 73 based on an input signal input via the input circuit 71.

  Signals are input to the input circuit 71, for example, the input device 75 that accepts user input operations, encoders 37 and 59, the piston position sensor 79 that detects the position of the injection piston 23, the servo valve 57, and the position of the moving rod 11. A rod position sensor 81 for detecting the pressure, a head pressure sensor 83 for detecting the pressure of the head side chamber 21h, and an accumulator pressure sensor 85 for detecting the pressure of the accumulator 31.

  The output circuit 73 outputs a signal, for example, a display 77 for displaying information to the user, servo drivers 39 and 61, a servo valve 57, and control of introduction of pilot pressure to various valves (not shown). It is a hydraulic circuit.

  The piston position sensor 79 detects the position of the injection piston 23 with respect to the cylinder tube 21 and indirectly detects the position of the plunger 5. For example, the piston position sensor 79 is fixed to or formed on the injection piston 23 and constitutes a linear encoder together with a scale portion (not shown) extending in the axial direction of the injection piston 23. The piston position sensor 79 or the control device 19 can detect the speed by differentiating the detected position.

  The rod position sensor 81 detects the position of the moving rod 11 with respect to the cylinder tube 21. The rod position sensor 81 is, for example, fixed to or formed on the moving rod 11 and constitutes a linear encoder together with a scale portion (not shown) extending in the axial direction of the moving rod 11. The rod position sensor 81 or the control device 19 can detect the speed by differentiating the detected position.

  The head pressure sensor 83 indirectly detects the pressure applied by the plunger 5 to the molten metal by detecting the pressure in the head side chamber 21h. The accumulator pressure sensor 85 is used for determining whether the accumulator 31 has been filled.

(Operation of injection device)
FIG. 2 is a diagram for explaining the operation of the injection apparatus 1. In FIG. 2, the horizontal axis indicates time. A solid line Lv indicates a change in injection speed, and a solid line Lp indicates a change in injection pressure. In the graph in which the solid lines Lv and Lp are drawn, the vertical axis indicates the magnitude of the injection speed and the injection pressure. In the lower part of the graph, operations of the injection piston 23, the moving rod 11, the injection motor 15, the servo valve 57, and the filling motor 35 are shown.

  In general, the injection device 1 performs low-speed injection, high-speed injection, and pressure increase (pressure increase) in order. That is, in the initial stage of injection, the injection device 1 advances the plunger 5 at a relatively low speed in order to prevent entrainment of the melt air, and then fills the melt without delaying the solidification of the melt. In view of the above, the plunger 5 is advanced at a relatively high speed. Thereafter, the injection device 1 increases the pressure of the molten metal in the cavity by the force in the direction in which the plunger 5 advances in order to eliminate sink marks in the molded product. Specifically, it is as follows.

(Low speed injection: t0 to t1)
Immediately before the start of low-speed injection, the injection device 1 is in the state shown in FIG. That is, the injection piston 23 and the pressure increasing piston 25 are located at the initial position such as the retreat limit. The moving rod 11 is inserted to the front of the housing portion 23 f of the injection piston 23, and the tip end portion 11 b is in contact with the contacted portion 23 g of the injection piston 23. The injection motor 15 and the filling motor 35 are stopped. The accumulator 31 has completed pressure accumulation. The servo valve 57 and the first check valve VLA to the fifth check valve VLE may be in an appropriate state as long as the release of the hydraulic fluid from the accumulator 31 is prohibited. For example, the servo valve 57 is closed. A check valve capable of introducing a closed pilot pressure is introduced with a closed pilot pressure, and a check valve capable of introducing only an open pilot pressure is not introduced with a pilot pressure.

  When a predetermined low-speed injection start condition is satisfied, for example, when the clamping of the fixed mold 101 and the movable mold 103 is completed and the molten metal is supplied to the sleeve 3, the control device 19 drives the injection motor 15. The moving rod 11 is moved forward. Further, the control device 19 stops the introduction of the closing pilot pressure to the second check valve VLB.

  As a result, the injection piston 23 (plunger 5) is pushed forward by the moving rod 11. Further, the hydraulic fluid discharged from the rod side chamber 21r as the injection piston 23 moves forward is discharged to the tank 29 via the second check valve VLB.

  In addition, in the head side chamber 21h whose volume increases with the advance of the injection piston 23, for example, the introduction of the closing pilot pressure to the first check valve VLA is stopped, so that the hydraulic fluid in the tank 29 becomes the fifth. Replenishment is performed via the check valve VLE and the first check valve VLA. Further, a flow path and a valve may be provided so that the working fluid is replenished from the pump 33 driven at a relatively low speed to the head side chamber 21h.

  The speed of the plunger 5 is controlled by adjusting the rotational speed of the injection motor 15. Specifically, the control device 19 feedback-controls the rotation speed of the injection motor 15 based on the speed of the plunger 5 detected by the piston position sensor 79 (or the rod position sensor 81).

(High-speed injection: t1 to t2)
When the position of the plunger 5 based on the detection value of the piston position sensor 79 reaches a predetermined high-speed switching position, the control device 19 stops the injection motor 15. Further, the control device 19 stops the introduction of the closing pilot pressure to the first check valve VLA and opens the servo valve 57 at an appropriate opening degree.

  As a result, hydraulic fluid is supplied from the accumulator 31 to the head side chamber 21h via the servo valve 57 and the first check valve VLA, and the injection piston 23 moves forward at a relatively high speed. As a result, the molten metal in the sleeve 3 is injected into the cavity 105 at a high speed by the plunger 5.

  Since the moving rod 11 is stopped with respect to the cylinder tube 21, the moving rod 11 moves rearward relative to the injection piston 23 that moves forward with respect to the cylinder tube 21.

  In the accommodating part 23f, the volume which can accommodate a hydraulic fluid expands by the movement rod 11 moving. And the accommodating part 23f is replenished with hydraulic fluid from the rod side chamber 21r through the opening not shown formed in the large diameter rod part 23ab.

  The rod side chamber 21r is reduced in volume as the injection piston 23 moves forward. In the present embodiment, the amount of expansion of the storage portion 23f is smaller than the reduction amount of the rod side chamber 21r (the cross-sectional area of the moving rod 11 is smaller than the pressure receiving area in the rod side chamber 21r of the piston portion 23b). The entire volume of the rod side chamber 21r is reduced. Excess hydraulic fluid is discharged from the rod side chamber 21r to the tank 29 via the second check valve VLB.

  The speed of the plunger 5 is controlled by adjusting the opening degree of the servo valve 57. Note that feedback control may be appropriately performed as in the low-speed injection.

(Decelerated injection: t2 to t3)
When the molten metal is filled to some extent in the cavity 105, the plunger 5 receives the reaction force from the filled molten metal and decelerates. The operation of each part is the same as that during high-speed injection. However, in order to mitigate the impact at the time of filling, appropriate deceleration control such as reducing the opening degree of the servo valve 57 when a predetermined deceleration start condition such as the plunger 5 reaches a predetermined deceleration position is satisfied. May be made.

(Pressure increase: t3 to t4)
When a predetermined pressure increase start condition is satisfied, the control device 19 stops introducing the closing pilot pressure to the third check valve VLC. The pressure increase start condition is, for example, that the detection value of the injection pressure detected by the head pressure sensor 83 has reached a predetermined value, or the detection position of the plunger 5 detected by the piston position sensor 79 is at a predetermined position. It has been reached.

  By stopping the introduction of the closing pilot pressure to the third check valve VLC, the hydraulic fluid is supplied from the accumulator 31 to the rear chamber 21g via the third check valve VLC. Further, the hydraulic fluid in the front side chamber 21f can be discharged to the tank 29 via the fourth flow path 47 and the rod side chamber 21r.

  Therefore, as described above, a pressure higher than the pressure of the hydraulic fluid in the rear side chamber 21g is applied to the head side chamber 21h by the pressure increasing function of the pressure increasing piston 25. The injection pressure reaches the final pressure. Further, the injection speed becomes 0 when the cavity 105 is completely filled with the molten metal.

  Note that a pilot pressure for closing the first check valve VLA is introduced. However, since the first check valve VLA is self-closed when the pressure in the head side chamber 21h is increased, the pilot pressure may not be introduced until an appropriate time such as the start of filling of the accumulator 31 described later. .

  Further, the movable distance L of the tip end portion 11b is set to be larger than the moving distance of the injection piston 23 in high speed injection and pressure increase, and the tip end portion 11b of the injection piston 23 is stopped until the injection piston 23 stops. The movement of the injection piston 23 is not hindered by coming into contact with the engaged portion 23k.

(Holding pressure: t4 to t5)
The control device 19 maintains the state where the injection pressure is the final pressure. During this time, the molten metal is cooled and solidified. When the molten metal solidifies, the control device 19 closes the servo valve 57 and introduces a pilot pressure to be closed to the second check valve VLB and the third check valve VLC. As a result, the supply of the hydraulic pressure from the accumulator 31 to the rear chamber 21g and the discharge of the hydraulic fluid from the rod side chamber 21r to the tank 29 are stopped, and the pressure holding ends.

  In addition, the control apparatus 19 determines whether the molten metal solidified suitably. For example, the control device determines whether or not the molten metal has solidified based on whether or not a predetermined time has passed since a predetermined time such as the time when the final pressure is obtained.

(Product protrusion)
Although not particularly illustrated, the biscuit may be pushed out by the plunger 5 when the molded product is taken out from the fixed mold 101 after completion of the pressure holding. The operation may be performed, for example, by controlling various valves similarly to high-speed injection or pressure increase and supplying hydraulic fluid from the accumulator 31 to the head side chamber 21h or the rear side chamber 21g. Further, for example, a flow path and a valve may be appropriately provided, and the hydraulic fluid may be supplied from the pump 33 to the head side chamber 21h or the rear side chamber 21g.

(Accumulator filling: t6-t7)
The control device 19 stops the introduction of the closing pilot pressure to the fourth check valve VLD and opens the servo valve 57. Then, the filling electric motor 35 is driven. As a result, the hydraulic fluid discharged from the pump 33 is supplied to the accumulator 31 via the fourth check valve VLD and the servo valve 57, and pressure accumulation in the accumulator 31 is performed.

  When the pressure accumulation completion condition of the accumulator 31 is satisfied, for example, when the pressure detected by the accumulator pressure sensor 85 reaches a predetermined pressure accumulation completion pressure, the control device 19 stops the charging motor 35 and goes to the fourth check valve VLD. Close pilot pressure is introduced and servo valve 57 is closed.

(Plunger retraction: t8 to t11)
The control device 19 rotates the injection motor 15 in the direction opposite to that at the time of injection to retract the moving rod 11. And when the front-end | tip part 11b of the movement rod 11 contact | abuts to the to-be-engaged part 23k of the back of the injection piston 23 (t9), the injection piston 23 will also begin to reverse | retreat.

  Note that the hydraulic fluid pushed out from the head side chamber 21h as the injection piston 23 moves backward is introduced into the first check valve, for example, by introducing pilot pressure to the first check valve VLA and the fifth check valve VLE. It is discharged to the tank 29 via the valve VLA and the fifth check valve VLE.

  Further, the hydraulic fluid is replenished to the rod side chamber 21r whose volume increases as the injection piston 23 moves backward, for example, by a pump 33 that is rotated at a relatively low speed. A check valve that can introduce pilot pressure that opens the second check valve VLB may be used, and the working fluid may be supplied from the tank 29 to the rod side chamber 21r using the negative pressure of the rod side chamber 21r.

  Thereafter, when the control device 19 detects that the moving rod 11 has reached the retreat limit based on the detection value of the rod position sensor 81, the control device 19 stops the injection motor 15 (t10). Here, the retreating limit of the moving rod 11 is a position that contacts the abutted portion 23g in front of the injection piston 23 shown in FIG. Does not reach the retreat limit.

  Therefore, the control device 19 starts to rotate the charging motor 35 at an appropriate rotation number (t10), and supplies the working fluid from the pump 33 to the rod side chamber 21r. Thereby, the injection piston 23 continues to move backward. Although the moving rod 11 is stopped, the moving rod 11 moves forward relative to the retreating injection piston 23.

  Thereafter, when the control device 19 detects that the injection piston 23 has reached the retreat limit based on the detection value of the piston position sensor 79 (t11), the control device 19 stops the rotation of the charging motor 35. At this time, the distal end portion 11 a of the moving rod 11 contacts the contacted portion 23 g of the injection piston 23.

  The pressure increasing piston 25 is retracted simultaneously with the retreat of the injection piston 23. For example, when the injection piston 23 is retracted by the moving rod 11 or the pump 33, the pressure increasing piston 25 is retracted by receiving pressure from the head side chamber 21h by prohibiting the discharge of the hydraulic fluid from the head side chamber 21h. Alternatively, when the injection piston 23 is moved backward by the pump 33, the pressure increasing piston 25 moves backward by supplying the hydraulic fluid supplied to the rod side chamber 21 r to the front side chamber 21 f via the fourth flow path 47.

  Note that the hydraulic fluid pushed out from the rear chamber 21g as the pressure-increasing piston 25 moves backward is, for example, introduced into the third reverse valve by introducing pilot pressure to the third check valve VLC and the fifth check valve VLE. It is discharged to the tank 29 through the stop valve VLC and the fifth check valve VLE.

  Further, the control device 19 can estimate from the detection value of the piston position sensor 79 or the like that the pressure increasing piston 25 has reached the retreat limit. A limit switch that is turned on or off when the pressure-increasing piston 25 reaches the backward limit may be provided.

  According to the above embodiment, the injection device 1 of the die casting machine DC1 includes the plunger 5 that pushes the molten metal into the cavity 105 and the injection cylinder device 7 that drives the plunger 5. The injection cylinder device 7 has an injection piston 23 whose front portion (small-diameter rod portion 23aa) is connected to the plunger 5, and a cylinder tube 21 that slidably accommodates a rear portion (piston portion 23b) of the injection piston 23. The inside of the cylinder tube 21 is divided into a front rod side chamber 21r and a rear head side chamber 21h by a piston portion 23b. The injection device 1 includes a hydraulic device 9 that can supply hydraulic fluid to the injection cylinder device 7, a moving rod 11 that is inserted behind the cylinder tube 21 and can push the injection piston 23 forward, and moves. A driving device 13 capable of driving the rod 11 in the axial direction with respect to the cylinder tube 21 is provided. The moving rod 11 is inserted so as to be movable in the axial direction with respect to the injection piston 23, and the distal end portion 11b is isolated from the head side chamber 21h.

  Therefore, when the high pressure hydraulic fluid is supplied to the head side chamber 21h to drive the injection piston 23, the hydraulic fluid in the head side chamber 21h does not act on the distal end portion 11b of the moving rod 11. As a result, for example, the injection motor 15 can be downsized to reduce the cost.

  The injection device 1 applies a driving force from the driving device 13 to the injection piston 23 in the low-speed injection, does not apply a driving force to the injection piston 23 from the hydraulic device 9, and drives in the high-speed injection and pressure increase. The device 13 further includes a control device 19 for controlling the driving device 13 and the hydraulic device 9 so that the driving force is not applied to the injection piston 23 from the device 13 and the driving force is applied to the injection piston 23 from the hydraulic device 9.

  Therefore, it is not necessary to cooperatively control the driving device 13 and the hydraulic device 9, and the control system is simple. As a result, it is possible to improve the stability of the low speed injection speed, the speed increasing performance in the high speed injection, and the pressure increasing performance in the pressure increase. Moreover, since the drive device 13 is not used in high-speed injection and pressure increase, the screw shaft 63 can be shortened.

  The moving rod 11 has an engaging portion (tip portion 11b) that engages with the injection piston 23 from the front to the rear. The control device 19 controls the drive device 13 to retract the plunger 5 after molding by retracting the moving rod 11 engaged with the injection piston 23. Therefore, effective use of the injection motor 15 is achieved. For example, the burden on the filling electric motor 35 for delivering the hydraulic fluid is reduced, and energy saving is expected.

<Second Embodiment>
(Configuration of injection device)
FIG. 3 is a diagram illustrating a configuration of a main part of the injection apparatus 201 according to the second embodiment. In FIG. 3, for convenience of illustration, the tank 29 is illustrated at a plurality of positions. However, a plurality of tanks may actually be arranged.

  The first point of the injection device 201 is that the injection piston 23 is entirely retracted by the moving rod 11, and the hydraulic fluid discharged from the head side chamber 21h or the like at this time is supplied to the accumulator 31 to fill the accumulator 31. It differs from the injection device 1 of the embodiment. Further, as a result of the above difference, the pump 33 and the like are not required. Specifically, it is as follows.

  In the drive device 213, the screw shaft 263 of the transmission mechanism 217 is formed longer than the screw shaft 63 of the first embodiment. The difference in length is equal to or greater than the movable distance L in the housing portion 23f of the distal end portion 11b. Further, the nut 65 (injection electric motor 15) is arranged behind the first embodiment at a distance corresponding to the extension of the screw shaft 263.

  Therefore, the driving device 213 can further retract the moving rod 11 by the movable distance L from the state of FIG. That is, the drive device 213 can retract the moving rod 11 to a position where the injection piston 23 reaches the retreat limit in a state where the tip end portion 11b is in contact with the engaged portion 23k of the injection piston 23. .

  In the hydraulic device 209, the pump 33 and the configuration related to the pump 33 are omitted. Specifically, the configuration related to the removed pump 33 includes the filling motor 35, the encoder 37, the servo driver 39, the fifth flow path 49, the eighth flow path 55, the fourth check valve VLD, and the second check valve. These are the valve VLB and the sixth check valve VLF.

  The rod side chamber 21r and the front side chamber 21f are connected only to the tank 29. In addition, in connection with the tank 29 of the rod side chamber 21r and the front side chamber 21f, the 2nd flow path 43 and the 4th flow path 47 may be used similarly to 1st Embodiment. As a valve for prohibiting the flow from the accumulator 31 or the like to the tank 29, a seventh check valve in which no pilot pressure is introduced is used instead of the fifth check valve VLE of the first embodiment, as in the sixth check valve VLF. A valve VLG is provided.

(Operation of injection device)
FIG. 4 is a view similar to FIG. 2 for explaining the operation of the injection apparatus 201. However, there is no operation diagram corresponding to the filling motor 35 in FIG.

(Low speed injection to holding pressure: t0 to t5)
The control of the hydraulic device 209 and the drive device 13 by the control device 19 is the same as that of the first embodiment except that the control of the valve deleted from the first embodiment is unnecessary.

(Plunger retraction and accumulator filling: t16 to t18)
At time t16, the control device 19 rotates the injection motor 15 in the direction opposite to that at the time of injection, similarly to the time t8 of the first embodiment, and moves the moving rod 11 backward. And when the front-end | tip part 11b of the movement rod 11 contact | abuts to the to-be-engaged part 23k of the back of the injection piston 23 (t17), the injection piston 23 will also begin to reverse | retreat.

  On the other hand, when the injection piston 23 (moving rod 11) moves backward, the control device 19 first introduces a pilot pressure that opens to the servo valve 57 and the third check valve VLC. Therefore, as the injection piston 23 moves backward, the pressure increasing piston 25 receives pressure from the hydraulic fluid in the head side chamber 21 h and moves backward while pushing the hydraulic fluid in the rear side chamber 21 g to the accumulator 31.

  Thereafter, when the control device 19 detects that the pressure increasing piston 25 has reached the retreat limit by the detection value of the rod position sensor 81 or an appropriate limit switch, the control device 19 introduces a pilot pressure to be closed to the third check valve VLC, An open pilot pressure is introduced into the first check valve VLA. The injection piston 23 continues to retreat while pushing the hydraulic fluid in the head side chamber 21h to the accumulator 31.

  In addition, the capacity | capacitance part 23f (t16-t17) in which the capacity | capacitance which accommodates hydraulic fluid expands as the moving rod 11 is pulled out from the injection piston 23, and the volume increases by the pressure-increasing piston 25 retreating. The working fluid is supplied from the tank 29 by negative pressure to the side chamber 21f and the rod side chamber 21r (t17 to t18) whose volume increases as the injection piston 23 moves backward.

  When the control device 19 detects that the injection piston 23 has reached the retreat limit based on the detection value of the piston position sensor 79 (or the rod position sensor 81), the control device 19 stops the injection motor 15, closes the servo valve 57, 1 Introducing a pilot pressure to close the check valve VLA.

(Next cycle preparation: t18-)
Although not particularly illustrated, the control device 19 drives the injection motor 15 in the same direction as during injection. Therefore, the moving rod 11 having the tip 11b abutted against the engaged portion 23k behind the injection piston 23 moves forward.

  When the control device 19 detects from the detection value of the rod position sensor 81 that the tip portion 11b has reached a position where it comes into contact with the contacted portion 23g in front of the injection piston 23, the control device 19 stops the injection motor 15. .

  Note that the hydraulic fluid pushed out from the housing portion 23f as the moving rod 11 is inserted into the injection piston 23 is discharged to the tank 29 through the rod side chamber 21r.

  According to the second embodiment described above, the moving rod 11 is inserted so as to be movable in the axial direction with respect to the injection piston 23, and the distal end portion 11b is isolated from the head side chamber 21h. Similar to the configuration, the action of the high-pressure hydraulic fluid on the distal end portion 11b of the moving rod 11 is suppressed.

  The control device 19 retracts the plunger 5 after molding by retracting the moving rod 11 engaged with the injection piston 23, and accumulator 31 discharges the hydraulic fluid discharged from the head side chamber 21 h as the injection piston 23 retracts. The hydraulic pressure device 209 and the driving device 213 are controlled so as to be supplied. Therefore, the injection motor 15 can be used more effectively than in the first embodiment. For example, it is possible to omit the filling electric motor 35 related to the filling of the accumulator 31, and energy saving is expected.

<Third Embodiment>
(Configuration of injection device)
FIG. 5 is a diagram illustrating a configuration of a main part of the injection apparatus 301 according to the third embodiment.

  The injection device 301 is configured with a run-around circuit for returning the hydraulic fluid discharged from the rod side chamber 21r to the head side chamber 21h, and the servo valve 57 is used for the hydraulic fluid discharged from the rod side chamber 21r. It differs from the first embodiment in that a so-called meter-out circuit is provided at a position where the flow rate can be controlled. Specifically, it is as follows.

  The hydraulic device 309 has a ninth flow path 352 that connects the rod side chamber 21r and the head side chamber 21h. A part of the ninth channel 352 on the rod side chamber 21r side is shared with a part of the second channel 43 on the rod side chamber 21r side, and a part of the ninth channel 352 on the head side chamber 21h side is This is shared with a part of the head side chamber 21h side of the one flow path 41. However, these need not be shared. The ninth flow path 352 constitutes a run-around circuit.

  The ninth flow path 352 is provided with an eighth check valve VLH for turning on and off the run-around circuit. The eighth check valve VLH allows the flow of hydraulic fluid from the rod side chamber 21r to the head side chamber 21h and prohibits the flow in the opposite direction when the pilot pressure is not introduced. Further, the eighth check valve VLH prohibits (closes) both flows when the pilot pressure is introduced.

  The servo valve 57 is disposed, for example, in a shared portion with the second flow path 43 on the rod side chamber 21r side of the ninth flow path 352.

  The hydraulic device 309 has a tenth flow path 354 for discharging the hydraulic fluid in the rear chamber 21g and a ninth check valve VLI for controlling the flow of the tenth flow path 354. The ninth check valve VLI allows the flow of hydraulic fluid from the rear chamber 21g and prohibits the flow in the opposite direction when the pilot pressure is not introduced. Further, the ninth check valve VLI prohibits (closes) both flows when the pilot pressure is introduced.

  The first check valve VLX and the third check valve VLY may have the same configuration as the first check valve VLA and the third check valve VLC of the first embodiment, but are closed in FIG. Therefore, it is a check valve into which only the pilot pressure is introduced.

  The injection device 301 has a rod pressure sensor 84 that detects the pressure in the rod side chamber 21r. The control device 19 can calculate the pressure that the plunger 5 applies to the molten metal based on the pressures detected by the head pressure sensor 83 and the rod pressure sensor 84.

(Operation of injection device)
FIG. 6 is a view similar to FIG. 2 for explaining the operation of the injection apparatus 301.

  The control by the control device 19 is generally the same as that of the first embodiment except for the control of the servo valve 57, the eighth check valve VLH, and the ninth check valve VLI. In the following, differences from the first embodiment will be mainly described, and description of common control / operation with the first embodiment will be omitted.

(Low speed injection-Deceleration injection: t0 to t3)
Before the start of the low-speed injection, the eighth check valve VLH and the ninth check valve VLI may be in an appropriate state, but are closed by introducing pilot pressure, for example.

  At the start of low-speed injection, the control device 19 opens the servo valve 57 and stops introducing pilot pressure to the eighth check valve VLH. As a result, the run-around circuit is turned on. On the other hand, the introduction of the closed pilot pressure is continued in the second check valve VLB in which the introduction of the closed pilot pressure is stopped in the first embodiment.

  Accordingly, the hydraulic fluid discharged from the rod side chamber 21r does not flow into the tank 29, but is returned to the head side chamber 21h via the eighth check valve VLH. The shortage of hydraulic fluid caused by the pressure receiving area of the rod side chamber 21r being smaller than the pressure receiving area of the head side chamber 21h is replenished via the sixth check valve VLF from the pump 33 driven at a relatively low speed, for example. The A flow path and a valve may be provided so that the hydraulic fluid is replenished from the tank 29 by the negative pressure in the head side chamber 21h. Note that the run-around circuit is kept on even in high-speed injection and deceleration injection.

(Intensification to holding pressure: t3 to t5)
In increasing pressure and holding pressure, the control device 19 introduces a pilot pressure to be closed to the eighth check valve VLH, and turns off the run-around circuit. Further, the introduction of the closing pilot pressure to the second check valve VLB is stopped, and the pressure in the rod side chamber 21r is set to the tank pressure as in the first embodiment. Accordingly, pressure increase and pressure holding are performed as in the first embodiment.

(Accumulator filling: t6-t7)
Except that it is not necessary to open and close the servo valve 57, it is the same as in the first embodiment.

(Plunger retraction: t8 to t10)
As in the first embodiment, the control device 19 performs injection by moving the moving rod 11 backward (t8 to t10) and supplying hydraulic fluid from the pump 33 to the rod side chamber 21r (t10 to t11). The piston 23 is retracted. However, the servo valve 57 is opened when supplying the hydraulic fluid to the rod side chamber 21r (t8 to t11).

  The hydraulic fluid in the head side chamber 21h is not particularly shown, but, for example, as in the first embodiment, the valve provided in the flow path connecting the head side chamber 21h and the tank 29 is opened to open the tank. 29 is discharged. The tenth flow path 354 is connected to the tank 29 via a flow path (not shown) on the head side chamber 21h side of the ninth check valve VLI, and the pilot pressure to close to the ninth check valve VLI is stopped. As a result, the hydraulic fluid in the rear chamber 21g is discharged to the tank 29.

  According to the above third embodiment, the moving rod 11 is inserted so as to be movable in the axial direction with respect to the injection piston 23, and the distal end portion 11b is isolated from the head side chamber 21h. Similar to the configuration, the action of the high-pressure hydraulic fluid on the distal end portion 11b of the moving rod 11 is suppressed.

  In addition, since the run-around circuit is provided, the capacity of the accumulator 31 can be reduced and the amount of hydraulic fluid in the tank 29 can be reduced. Furthermore, the brake performance can be improved by the meter-out circuit.

<Fourth Embodiment>
FIG. 7 is a diagram illustrating a configuration of a main part of an injection device 401 according to the fourth embodiment.

  The injection device 401 includes a single-acting injection cylinder device 407, a point where the accommodating portion 23f is not filled with hydraulic fluid, and two sets of drive devices 13 (two sets of drive devices 13). Is different from that of the third embodiment. Specifically, it is as follows.

  The injection cylinder device 407 is a single-acting type as described above. That is, the cylinder tube 421 of the injection cylinder device 407 has only a portion corresponding to the injection cylinder portion 21a of the other embodiment, and does not have a portion corresponding to the pressure increasing cylinder portion 21b. The injection cylinder device 407 includes only the injection piston 423 and does not include the pressure increasing piston 25.

  In response to the fact that the injection cylinder device 407 is a single-acting type, the hydraulic pressure device 409 is configured to supply and discharge the hydraulic fluid to the pressure-increasing cylinder portion 21b (the third flow path 45, the fourth flow rate). The channel 47, the tenth channel 354, valves provided in these channels, etc.) are not provided.

  The accommodating portion 23f of the injection piston 423 communicates with the outside of the cylinder tube 421 through a gas hole 423h formed in the rod portion 423a (for example, open to the atmosphere). Therefore, in the accommodating portion 23f, when the gas (for example, air) is filled and the volume of the accommodating portion 23f is reduced or enlarged as the moving rod 11 enters or leaves the accommodating portion 23f, the accommodating portion 23f becomes the gas hole. Gas is discharged or supplied via 423h.

  One end of the gas hole 423h opens at an appropriate position of the housing portion 23f, and the other end is located at a position exposed from the cylinder tube 21 even when the injection piston 423 is positioned at the retreat limit in the rod portion 423a. It is open. For example, one end of the gas hole 423h is opened at the center of the contacted portion 23g, and the large-diameter rod portion 423ab and the small-diameter rod portion 423aa are extended from the one end in the axial direction, and then the small-diameter rod portion 423aa is moved in the radial direction. The other end opens at the outer peripheral surface of the small diameter rod portion 423aa.

  In the driving device 413, each screw shaft 63 (each driving device 13) is arranged in parallel (in parallel) with the moving rod 11, and its rear side end portion is connected to the rear side end portion of the moving rod 11 and the connecting member 418. Are connected by Further, the two screw shafts 63 (the two drive devices 13) are disposed at rotationally symmetric positions with respect to the moving rod 11. That is, even if the two driving devices 13 are rotated 180 degrees around the moving rod 11, the positions of the two screw shafts 63 are the same. The two driving devices 413 are synchronously controlled by the control device 19 so that the moving rod 11 does not tilt.

  The operation of the injection device 401 according to the fourth embodiment may be the same as that according to the third embodiment except that the portion related to the driving of the pressure increasing piston 25 is omitted. The pressure increase is performed when the pressure in the head side chamber 21 h approaches the pressure in the accumulator 31 after the molten metal is almost filled in the cavity 105.

  According to the fourth embodiment described above, the moving rod 11 is inserted so as to be movable in the axial direction with respect to the injection piston 423, and the distal end portion 11b is isolated from the head side chamber 21h. Similar to the configuration, the action of the high-pressure hydraulic fluid on the distal end portion 11b of the moving rod 11 is suppressed.

  In addition, since the two drive devices 13 are provided in parallel to the moving rod 11 and at a rotationally symmetric position with respect to the moving rod 11, the drive device 13 is connected in series to the moving rod 11. Compared to the first to third embodiments to be arranged, the space behind the injection cylinder device 407 can be shortened, and the moving rod 11 is tilted similarly to the first to third embodiments. Generation of force is suppressed.

  Since the inside of the accommodating portion 23f is filled with gas and opened to the outside of the cylinder tube, effects such as labor saving by reducing the total amount of hydraulic fluid and weight reduction of the injection piston 423 are obtained.

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

  The above-described embodiments may be appropriately combined. For example, the single-acting injection cylinder device of the fourth embodiment includes the uniaxial drive device of the first to third embodiments and / or the injection device in which the accommodating portion (23f) is filled with the working fluid. Conversely, the pressure-increasing injection cylinder device according to the first to third embodiments may have the biaxial drive device according to the fourth embodiment and / or the hydraulic fluid may be filled in the accommodating portion. It may be applied to an injection device that is not. Further, for example, the uniaxial drive device of the first to third embodiments may be combined with the injection cylinder device in which the hydraulic fluid is not filled in the accommodating portion of the fourth embodiment, or the fourth embodiment. The two-axis drive device according to the embodiment may be combined with the injection cylinder device in which the hydraulic fluid is filled in the housing portion according to the first to third embodiments. The configuration and operation of filling the accumulator 31 by the retraction of the moving rod 11 engaged with the injection piston of the second embodiment is such that the injection piston 23 is retreated halfway by the movement rod 11 of the first embodiment or the like. It may be applied, may be applied to a hydraulic device having the meter-out circuit or run-around circuit of the third embodiment, or may be applied to the drive device of the fourth embodiment. In addition, the configuration and operation in which the injection piston 23 is retracted by the moving rod 11 of the first embodiment and the working fluid in the head side chamber 21h is discharged to the tank 29 is the same as the configuration of the second embodiment. You may apply to the structure and operation | movement which makes it reverse.

  The molding machine is not limited to a die casting machine. For example, the molding machine may be another metal molding machine, a plastic injection molding machine, or a molding machine that molds a material obtained by mixing wood powder with a thermoplastic resin or the like. Good. Further, the injection device is not limited to horizontal mold clamping horizontal injection, and may be vertical mold clamping vertical injection or horizontal mold clamping vertical injection, for example. The hydraulic fluid is not limited to oil and may be water, for example.

  The drive device preferably includes an electric motor. However, the driving device is not necessarily limited to the one including the electric motor, and may be various types that generate the driving force. Further, the drive device may be a hybrid actuator in which an electric motor and a hydraulic cylinder are integrated. The electric motor is not limited to a rotary type, and may be a linear motor. In the case of a linear motor, the driving force of the linear motor may be directly transmitted to the moving rod without using a transmission mechanism.

  When the electric motor is a rotary type, the transmission mechanism (conversion mechanism) that converts the rotation of the electric motor into a translational motion and transmits it to the moving rod is not limited to a screw mechanism. For example, a rack and pinion mechanism may be used.

  When the transmission mechanism is a screw mechanism, the screw mechanism may be one in which a nut is fixed to the moving rod and the moving rod is driven by rotation of the screw shaft. Further, the screw mechanism is not limited to a nut or a screw shaft fixed to the rotor of the electric motor, and may be one in which the rotation of the electric motor is transmitted via a gear mechanism or the like.

  From the viewpoint of suppressing the generation of a force that tilts the moving rod, the one or more driving devices are preferably arranged in parallel at a position that is coaxial or rotationally symmetric with respect to the moving rod as in the embodiment. . However, the driving device may be arranged at an appropriate position with respect to the moving rod, such as one driving device arranged in parallel with the moving rod.

  In addition, when a plurality of driving devices are arranged in parallel at rotationally symmetric positions with respect to the moving rod, the number of driving devices is not limited to two. For example, three drive devices (starting points of translation) may be arranged around the moving rod at 120 ° intervals, or four drive devices may be arranged around the moving rod at 90 ° intervals. In other words, the rotational symmetry is not limited to 2-fold symmetry, and may be 3-fold symmetry or 4-fold symmetry.

  In the first to third embodiments, the pressure increasing piston 25 is provided with the rear portion 25c extending from the cylinder tube 21, but the rear portion may be omitted. In this case, the moving rod is sealed both between the through hole (25h) of the pressure increasing piston and the opening at the rear end of the pressure increasing cylinder portion 21b. In the single acting cylinder, the injection piston may be provided with a rear portion protruding from the cylinder tube, similarly to the pressure increasing pistons of the first to third embodiments.

  In the embodiment, the tip of the moving rod has an enlarged diameter and can be engaged with the injection piston when retreating. However, there is no need to increase the diameter of the tip. Also in the injection piston, it is not necessary to form the engaged portion (23k) by enlarging the accommodating portion (23f) than the sliding hole (23e).

  The injection piston is connected to the plunger and is slidable in the cylinder tube. In addition, the injection piston is pressed by the tip of the moving rod (contacted portion 23g), and behind the pressed portion. The isolation part (the part including the piston part 23b and the sliding hole 23e) that isolates the tip of the moving rod from the head side chamber and the part that connects the pressed part and the isolation part (the accommodating part 23f of the injection piston 23) are formed. If it has a (cylindrical part), the shape may be changed suitably.

  For example, in the embodiment, the injection piston 23 has a cylindrical portion that forms the accommodating portion 23f, but the cylindrical portion is connected to a plurality of rod-shaped members that connect the contacted portion 23g and the piston portion 23b. It may be replaced.

  Further, for example, the sliding hole 23e has a length in the penetrating direction shorter than the axial length of the piston portion 23b, and the accommodating portion 23f extends to the inside of the piston portion 23b, and the movable distance L becomes as long as possible. It may be made like.

  Further, for example, in the embodiment, the large-diameter rod portion 23ab extends while being sealed with the cylinder tube 21, but the small-diameter rod portion 23aa may be extended while being sealed with the cylinder tube 21.

  Further, for example, the amount of increase in the volume of the accommodating portion 23f in high-speed injection is the same as the amount of reduction in the volume of the rod-side chamber 21r, or the amount of expansion in the capacity of the accommodating portion 23f in high-speed injection is the same as that of the rod-side chamber 21r. The size of the accommodating portion 23f and the like may be set so as to be larger than the volume reduction amount.

  As illustrated in the second embodiment, since the injection piston can be retracted to the retreat limit by the retraction of the moving rod engaged with the injection piston, the rod side chamber (21r) needs to be filled with the hydraulic fluid. There is no. For example, the rod side chamber may be opened to the outside of the cylinder tube through a hole formed in the cylinder tube. In addition, the accommodation part (23f) of the injection piston not filled with the hydraulic fluid as in the fourth embodiment may be opened to the outside by communicating with such a rod side chamber (the gas hole 423h is formed). May be omitted.)

  As illustrated in the fourth embodiment, the accommodation portion (23f) of the injection piston may be connected to the outside via a port formed in a portion exposed from the cylinder tube of the injection piston. In this case, the accommodating part may be supplied and discharged with the hydraulic fluid via the port.

  The distal end of the moving rod may not directly contact the injection piston. For example, another member may be interposed between the tip of the moving rod and the pressed portion (contacted portion 23g) of the injection piston (however, the other member is fixed to the injection piston or the moving rod). If so, it can be regarded as a part of it.) Further, for example, the moving rod is configured such that the tip of the moving rod slides on the housing portion, and the discharge / replenishment of the hydraulic fluid between the pressed portion and the tip of the moving rod can be controlled. A working fluid may be interposed between the tip and the pressed portion of the injection piston.

  The hydraulic device can be appropriately configured, and the connection and sharing of various flow paths and the arrangement of various valves can be appropriately changed. Although a pilot type check valve is frequently used as a valve for controlling the flow of hydraulic fluid, other control valves such as a direction switching valve may be used instead of the check valve.

  As described in the embodiment, it is preferable that the moving rod is not driven in high-speed injection or the like. However, the moving rod may be driven in high-speed injection or the like. At this time, the moving rod may contribute to the advance of the injection piston by abutting the injection piston, or may be slower than the advance speed of the injection piston and may not contribute to the advance of the injection piston. Further, the low speed injection or the high speed injection may be realized by multi-stage shift.

  The moving rod may not contribute to the retraction of the injection piston. For example, the injection piston may be retracted only by supplying hydraulic fluid from the pump to the rod side chamber. In this case, it is preferable that the moving rod is moved backward by the injection motor at an appropriate timing and speed so as not to hinder the backward movement of the injection piston.

  The retraction of the injection piston without accumulator filling may be performed before the accumulator filling, may be performed simultaneously with the accumulator filling, or may be performed after the accumulator filling.

  Each member may be formed integrally or may be composed of a plurality of members. For example, in the injection piston, the small-diameter rod portion, the large-diameter rod portion, and the piston portion may be formed separately and fixed to each other, or the small-diameter rod portion and the large-diameter rod portion, or the large-diameter rod portion and the piston. The part may be formed integrally.

  DESCRIPTION OF SYMBOLS 1 ... Injection device, 5 ... Plunger, 7 ... Injection cylinder device, 9 ... Hydraulic device, 11 ... Moving rod, 13 ... Drive device, 21 ... Cylinder tube, 21h ... Head side chamber, 21r ... Rod side chamber, 23 ... Injection piston 105 ... cavity.

Claims (8)

A plunger that pushes the molding material into the cavity;
An injection piston having a front portion connected to the plunger and a cylinder tube that slidably accommodates a rear portion of the injection piston, and the inside of the cylinder tube is a front rod by the rear portion of the injection piston. An injection cylinder device partitioned into a side chamber and a rear head side chamber;
A hydraulic device capable of supplying hydraulic fluid to the head side chamber;
A moving rod inserted behind the cylinder tube and capable of pushing the injection piston forward;
A driving device capable of driving the moving rod in the axial direction with respect to the cylinder tube;
Have
The injection piston is formed with a sliding hole that opens to the head side chamber,
The moving rod is inserted into the sliding hole so as to be axially movable with respect to the injection piston, and the tip is isolated from the head side chamber so that the pressure of the hydraulic fluid in the head side chamber does not act on the tip. Injection machine for molding machines. The driving device includes:
A rotary electric motor,
A transmission mechanism that converts rotation of the electric motor into translational motion and transmits it to the moving rod;
The injection device for a molding machine according to claim 1, comprising: In low-speed injection, the driving device applies a driving force to the injection piston, and the hydraulic device does not apply a driving force to the injection piston.
In high-speed injection and pressure increase, the driving device does not apply driving force to the injection piston, and the hydraulic device applies driving force to the injection piston.
The injection device for a molding machine according to claim 1, further comprising a control device that controls the driving device and the hydraulic device. The injection piston has an accommodating portion that is larger in diameter than the sliding hole in front of the sliding hole,
The moving rod is provided at a rod main body capable of sliding in the sliding direction in the axial direction, and at the tip of the rod main body, and is movable in the axial direction within the accommodating portion, and has a larger diameter than the rod main body. An engagement portion that is formed and engageable from the front to the rear with respect to the inner rear end surface of the housing portion ,
There is provided a control device for controlling the drive device so that the plunger moves backward after the molding by moving the engagement rod engaged with the inner rear end surface of the housing portion . The injection apparatus of the molding machine of any one of Claims 1-3. The hydraulic device has an accumulator capable of supplying hydraulic fluid to the head side chamber during high-speed injection,
5. The control device supplies the working fluid discharged from the head side chamber as the injection piston moves backward to the accumulator, and controls the driving device and the hydraulic device so as to fill the accumulator. The injection device of the molding machine described in 1. The injection device for a molding machine according to any one of claims 1 to 5, wherein the hydraulic device has a run-around circuit that communicates the rod-side chamber and the head-side chamber. The injection device for a molding machine according to any one of claims 1 to 6, wherein the hydraulic device has a flow rate control valve capable of adjusting a flow rate of the hydraulic fluid discharged from the rod side chamber. The injection of the molding machine according to any one of claims 1 to 7, wherein the plurality of driving devices are provided in parallel with the moving rod and at rotationally symmetric positions with respect to the moving rod. apparatus.

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