JP2013075300A - Injection device for molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection device for molding machine, capable of suitably performing injection by a cylinder device and another drive unit.SOLUTION: A control device 15 drives, in low-speed injection, a plunger 5 only by the driving force of the drive unit 11 with an output member 71 being in contact with a joint 27 fixed to a piston rod 25 in a forward direction, and drives, in high-speed injection, the plunger 5 only by the driving force of the cylinder device 7 with the connection by an attachment/detachment portion 13 being released, and also moves the piston rod 25 forward relatively to a driven portion. When the plunger is retreated, the control device retreats the plunger 5 by the driving force of the drive unit 11 with the connection by the attachment/detachment portion 13 being attained.

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 that pushes out a molding material is driven by a combination of a hydraulic device and another driving device (for example, an electric motor) (for example, Patent Document 1). Further, there is known a hybrid drive mechanism in which a cylinder device and a ball screw mechanism driven by an electric motor are arranged in parallel and connected to each other (for example, Patent Document 2). In Patent Document 3, in a hybrid injection device, a driving mechanism in which a cylinder device and a ball screw mechanism are arranged in parallel and connected to each other is used. The injection is performed by the driving force of the ball screw mechanism, and the pressure increase / holding pressure is performed by the cylinder device. In the pressure increase / holding pressure, torque control of the ball screw mechanism is performed so that the control torque of the ball screw mechanism does not become a reaction force of the cylinder device.

JP 2000-84654 A JP 07-137105 A JP 2006-887 A

  The technique disclosed in Patent Document 3 has various disadvantages. For example, the injection speed is limited by the limit speed of the ball screw mechanism.

  The objective of this invention is providing the injection apparatus of the molding machine which can perform injection suitably with a cylinder apparatus and another drive device.

  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, a cylinder device that has a piston rod connected to the plunger, and a driven portion, and the driven portion is A drive device that can be driven in a direction parallel to the piston rod, and a connection that restricts relative advancement of the piston rod and the driven part relative to at least the driven part of the piston rod and the connection can be released. And a control device for controlling the cylinder device and the driving device, and the control device is configured to move the piston rod relative to the driven portion relative to the driven portion during low-speed injection. And at least one of the contact of the driven part with respect to the member fixed to the piston rod in the forward direction In the state, the plunger is driven only by the driving force of the driving device among the driving force of the driving device and the driving force of the cylinder device, and in high-speed injection, the connection by the detachable portion is released, Of the driving force of the driving device and the driving force of the cylinder device, the plunger is driven only by the driving force of the cylinder device, and the piston rod is moved forward relative to the driven portion, and the plunger is retracted. Controls the cylinder device and the drive device so that the plunger is retracted by the drive force of the drive device in a state where the attachment / detachment portion is connected.

  Preferably, the control device causes the cylinder device and the drive so that the plunger is retracted only by the drive force of the drive device out of the drive force of the drive device and the drive force of the cylinder device when the plunger is retracted. Control the device.

  Preferably, the control device is configured to drive the cylinder device among the driving force of the driving device and the driving force of the cylinder device in a state where the connection by the detachable portion is released at least at the start of the pressure increase. The cylinder device and the piston device are driven only by force, so that the driven portion reaches a position connectable to the piston rod by the attaching / detaching portion between the start of pressure increase and the end of pressure holding. The drive device is controlled.

  Preferably, the control device drives the plunger by the driving device in the product extrusion follow-up, and when the load becomes a predetermined set value or more, drives the plunger together with the cylinder device, When it becomes less than the set value, the cylinder device and the driving device are controlled so as to drive the plunger without using the cylinder device together.

  Preferably, the injection device further includes a pump capable of delivering hydraulic fluid, a pump electric motor for driving the pump, and an accumulator capable of supplying hydraulic fluid to the cylinder device. The hydraulic fluid is delivered only to the accumulator of the cylinder device and the accumulator.

  Preferably, the pump is a constant-capacity pump whose discharge amount in one cycle is not variable, and the pump motor is a constant-speed motor that is open-loop controlled.

  Preferably, the injection device further includes an air-cooled cooler that cools the working fluid.

  Preferably, the driving device includes a guide bar extending in parallel with the piston rod in a backward direction from the driven portion, and a guide portion that guides the guide bar so as to be movable in the axial direction thereof.

  Preferably, the drive device includes a rotary injection motor, and a transmission mechanism that converts rotation of the injection motor into translational motion and transmits the translation motion to the driven portion.

  Preferably, the attaching / detaching portion connects and releases the connection between the piston rod and the driven portion by engaging and releasing the hook with the engaging member.

  According to the present invention, injection can be suitably performed by the cylinder device and another driving device.

The schematic diagram which shows the structure of the principal part of the injection device of the die-casting machine which concerns on embodiment of this invention. The figure which shows the detail of the drive device of the injection device of FIG. The figure explaining operation | movement of the injection device of FIG.

  FIG. 1 is a diagram showing a configuration of a main part of an injection apparatus 1 of a die casting machine DC1 according to an 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, a cylinder device 7 that drives the plunger 5, and a supply of hydraulic fluid (for example, oil) to the cylinder device 7. The hydraulic device 9 for driving by the above, the driving device 11 for driving the plunger 5, the detachable part 13 for connecting and releasing the cylinder device 7 and the driving device 11, and the control device 15 for controlling these devices. have.

  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: cylinder device 7, hydraulic device 9, etc.)
The cylinder device 7 is constituted by, for example, a single-acting cylinder device, and is fixed to the cylinder tube 21, a piston 23 slidable inside the cylinder tube 21, the piston 23, and extends from the cylinder tube 21. And a piston rod 25.

  The cylinder tube 21 is, for example, a cylindrical body having a circular inner cross-sectional shape. The inside of the cylinder tube 21 is partitioned by the piston 23 into a rod side chamber 21r on the side from which the piston rod 25 extends and a head side chamber 21h on the opposite side. By supplying the hydraulic fluid to the head side chamber 21h, the piston 23 can move forward (move toward the plunger 5).

  The cylinder device 7 is disposed coaxially with the plunger 5, the piston rod 25 is connected to the plunger 5 via a joint 27, and the cylinder tube 21 is fixedly provided to a mold clamping device (not shown) or the like. It has been. Accordingly, the plunger 5 advances in the sleeve 3 by the forward movement of the piston 23 relative to the cylinder tube 21.

  In addition, since the plunger 5 and the piston rod 25 are connected coaxially, “parallel to the plunger 5” and “parallel to the piston rod 25” may be referred to without particular distinction. The term “connection” and “connection to the piston rod 25” may be referred to without any particular distinction.

  The hydraulic device 9 includes a tank 29 that stores hydraulic fluid, a pump 31 that sends hydraulic fluid from the tank 29, a pump motor 33 that drives the pump 31, and an accumulator 35 that supplies hydraulic fluid to the cylinder device 7. And a cooler 39 for cooling the hydraulic fluid.

  The tank 29 is an open tank, for example, and holds the working fluid under atmospheric pressure. The tank 29 receives the working fluid discharged from the cylinder device 7 and supplies the working fluid to the accumulator 35 through the pump 31.

  The pump 31 may be a rotary pump that discharges hydraulic fluid by rotation of a rotor such as a gear pump or a vane pump, or discharges hydraulic fluid by reciprocation of a piston such as an axial plunger pump or a radial plunger pump. A plunger pump may be used.

  The pump 31 is, for example, a constant capacity pump in which the discharge amount in one cycle of movement of the rotor and piston is fixed. However, the pump 31 may be a variable displacement pump whose discharge amount is variable. The pump 31 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 pump motor 33 is provided to function as, for example, a constant speed motor. That is, the pump motor 33 is not provided as a servo motor in the servo mechanism, but is provided in an open loop. The pump motor 33 is preferably a three-phase induction motor, and rotates at a rotational speed corresponding to the frequency of the supplied AC power. However, the pump motor 33 may be provided as a servo motor, or may be configured by a synchronous motor or a DC motor.

  In the description of the operation described later, when the pump motor 33 is stopped, the pump motor 33 may be in a torque-free state, or (in the case of a servo motor), stopped at a fixed position. It may be controlled to include the brake, 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 pump motor 33 is stopped.

  The accumulator 35 may be configured 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, and a prada type. For example, the accumulator 35 is a gas pressure type, cylinder type, or prada type accumulator, and the gas (for example, air or nitrogen) held in the accumulator 35 is compressed to be compressed, and the accumulator 35 is operated by the pressure thus stored. Supply liquid.

  The cooler 39 is constituted by, for example, an air-cooled cooler, and has a pipe line exposed to the atmosphere through which the working fluid circulates. The cooler 39 is exposed to an airflow generated by rotation of the rotor of the pump electric motor 33 or generated by rotation of a fan fixed to the rotor, for example.

  As will be described later, in the present embodiment, the tank 29, the pump 31 and the pump motor 33 are reduced in size and the capacity of the pump 31 and the pump motor 33 is reduced. It can be constituted by a commercially available unitized one. In this case, the cooler 39 may also be included in the unit.

  The hydraulic device 9 has a plurality of flow paths that connect the cylinder device 7, the tank 29, the pump 31, and the accumulator 35 to each other, and a plurality of valves that control the flow of hydraulic fluid in the plurality of flow paths. . 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 connects the first flow path 41 that connects the accumulator 35 and the head side chamber 21h, the second flow path 43 that connects the rod side chamber 21r and the tank 29, and the rod side chamber 21r and the head side chamber 21h. And a third flow path 45. The first flow path 41 and the third flow path 45 are partially shared with each other on the head side chamber 21h side, and the second flow path 43 and the third flow path 45 are shared with each other on the rod side chamber 21r side. Has been. However, these need not be shared.

  The injection device 1 can advance the piston 23 by supplying hydraulic fluid from the accumulator 35 to the head side chamber 21h via the first flow path 41. Further, the injection device 1 can discharge the hydraulic fluid pushed out from the rod side chamber 21r as the piston 23 moves forward to the tank 29 through the second flow path 43. In other words, the injection apparatus 1 can depressurize the rod side chamber 21r. Further, the injection device 1 can return the working fluid pushed out from the rod side chamber 21r as the piston 23 advances to the head side chamber 21h via the third flow path 45. That is, the third flow path 45 constitutes a run-around circuit.

  The hydraulic device 9 has a fourth flow path 47 that connects the discharge port of the pump 31 and the accumulator 35. A part of the fourth channel 47 on the accumulator 35 side is shared with a part of the first channel 41 on the accumulator 35 side. However, these need not be shared. The injection device 1 is capable of accumulating the accumulator 35 by supplying hydraulic fluid from the pump 31 to the accumulator 35 via the fourth flow path 47.

  The hydraulic device 9 has a servo valve 51 provided in a shared portion of the second flow path 43 and the third flow path 45 on the rod side chamber 21r side. The servo valve 51 can adjust the flow rate steplessly by opening with an opening degree corresponding to the input voltage. The servo valve 51 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 51 is constituted by, for example, a flow rate control valve with pressure compensation. The servo valve 51 can control the operation (speed) of the cylinder device 7 by controlling the flow rate of the hydraulic fluid discharged from the rod side chamber 21r, and constitutes a so-called meter-out circuit.

  The hydraulic device 9 has a first check valve VLA to a fourth check valve VLD. At least one of these is controlled by introducing pilot pressure. As the pilot pressure, for example, the pressure of the accumulator 35 is used via a hydraulic circuit (not shown). The arrangement and function of the first check valve VLA to the fourth check valve VLD are specifically as follows.

  The first check valve VLA is provided in the first flow path 41. When the pilot pressure is not introduced, the first check valve VLA prohibits the flow of hydraulic fluid from the accumulator 35 side to the head side chamber 21h side and allows the flow in the opposite direction. Further, the first check valve VLA permits (opens) both flows when the pilot pressure 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 in the opposite direction. 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. The third check valve VLC allows the flow of hydraulic fluid from the rod side chamber 21r side to the head side chamber 21h side and prohibits the flow in the opposite direction when the pilot pressure is not introduced. The third check valve VLC prohibits (closes) both flows when the closed pilot pressure is introduced, and allows both flows when the open pilot pressure is introduced ( be opened).

  The fourth check valve VLD is provided in the fourth flow path 47. The fourth check valve VLD allows the flow of hydraulic fluid from the pump 31 side to the accumulator 35 side and prohibits the flow in the opposite direction.

  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 31 to an appropriate device such as a cylinder device for the core.

(Configuration of electric drive system: drive device 11, detachable portion 13, etc.)
FIG. 2 is a schematic side view partially including a cross-sectional view showing details of the driving device 11 and the detachable portion 13. Note that the left side of FIG. 2 is the forward direction of the plunger.

  The drive device 11 is for optimizing the operation by suppressing the inclination of the injection motor 53, the transmission mechanism 55 that transmits the driving force of the injection motor 53 to the plunger 5 (piston rod 25), the transmission mechanism 55, and the like. The guide mechanism 57 is provided. The drive device 11 includes an output member 71 interposed between the transmission mechanism 55, the guide mechanism 57, the piston rod 25 (strictly, the joint 27), and the attaching / detaching portion 13, and the driving force of the transmission mechanism 55 is output. It is transmitted to the piston rod 25 via the member 71.

  The injection motor 53 is, for example, a rotary electric motor, and although not particularly illustrated, the stator constituting one of the field and the armature and the other of the field and the armature are configured to be rotatable with respect to the stator. Rotor. The injection motor 53 may be a DC motor or an AC motor, or may be an induction motor or a synchronous motor. The injection motor 53 is arranged in parallel with the cylinder device 7. That is, the rotating shaft of the rotor and the output shaft 53 a are parallel to the piston rod 25.

  The injection motor 53 is configured as a servo motor, for example, and forms a servo mechanism together with an encoder 59 that detects the rotation of the injection motor 53 and a servo driver 61 that supplies power to the injection motor 53.

  The injection motor 53 is preferably a motor with a brake. For example, although not particularly illustrated, the injection motor 53 includes a disk that rotates with respect to the stator together with the rotor, a disk that cannot rotate with respect to the stator, and a spring that generates a spring force that abuts these two disks. And an armature capable of separating the two disks against the spring force.

  In the description of the operation to be described later, when the injection motor 53 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 53 is stopped. Is the same as the pump motor 33.

  The servo driver 61 supplies power to the injection motor 53 so that the instructed position control and / or speed control is performed. For example, if the injection motor 53 is an AC motor, the servo driver 61 supplies electric power having a frequency corresponding to the instructed speed to the injection motor 53. Further, the servo driver 61 can detect and output a load of the injection motor 53 (directly, for example, a current flowing through the injection motor 53).

  The transmission mechanism 55 converts the rotation of the injection motor 53 into translational motion and transmits it to the plunger 5. The transmission mechanism 55 is constituted by, for example, a screw mechanism, and includes a screw shaft 63 that is rotationally driven by the injection motor 53, and a nut 65 that is screwed to the screw shaft 63.

  The screw shaft 63 is, for example, arranged in parallel to the piston rod 25 and coaxially with the injection motor 53, and is connected to the output shaft 53a of the injection motor 53 via a coupling. In other words, the transmission mechanism 55 is arranged in parallel with the piston rod 25. Further, the screw shaft 63 is supported so as to be rotatable with respect to the cylinder tube 21 and the like and not movable in the axial direction. As will be described later, the rotation of the nut 65 around the screw shaft 63 is restricted by the guide mechanism 57.

  When the screw shaft 63 is rotationally driven by the injection motor 53, the nut 65 screwed with the screw shaft 63 moves in the axial direction of the screw shaft 63. That is, the nut 65 is driven in parallel with the piston rod 25.

  The guide mechanism 57 includes a guide bar 67 disposed in parallel to the piston rod 25 and a guide portion 69 that guides the guide bar 67 in the axial direction. The guide bar 67 is, for example, an axial member having a circular cross section, and the guide portion 69 is a member having a hole portion into which the guide bar 67 is slidably inserted in the axial direction.

  Although not particularly illustrated, the guide portion 69 is fixed to the cylinder tube 21 by being fixed to a member that supports the cylinder tube 21 of the cylinder device 7. By inserting the guide bar 67 into the guide portion 69, the cylinder tube 21 is restricted from moving in the direction perpendicular to the axis and tilting the axis, and is allowed to move in the axial direction.

  The guide portion 69 has two or more holes spaced apart in the axial direction of the guide bar 67 so that the inclination of the guide bar 67 can be suitably suppressed while reducing the sliding resistance with respect to the guide bar 67. Preferably it is.

  The output member 71 includes, for example, a connecting member 72 that connects the nut 65 and the guide bar 67, and an abutting member 73 that is interposed between the connecting member 72 and the piston rod 25 (strictly, the joint 27). ing.

  The connecting member 72 includes, for example, a portion that surrounds the nut 65 and is fixed to the nut 65, and a portion that extends from the portion in the radial direction of the nut 65 and is fixed to one end of the guide bar 67. Yes. The guide bar 67 extends from the connecting member 72 in the retracting direction of the plunger 5 (on the cylinder device 7 side).

  By connecting the nut 65 and the guide bar 67 by the connecting member 72, the inclination of the nut 65 with respect to the screw shaft 63 is restricted and the rotation around the screw shaft 63 is restricted. Since the guide mechanism 57 and the output member 71 contribute to the restriction of the movement of the nut 65 as described above, the guide mechanism 57 and the output member 71 may be regarded as a part of the transmission mechanism 55.

  The contact member 73 is fixed to the connecting member 72 (nut 65) and can contact the joint 27 in the forward direction of the plunger 5. For example, the abutting member 73 is formed in a shape (preferably annular) surrounding the piston rod 25 and can abut against the end surface of the joint 27 on the piston rod 25 side over the entire circumference. The contact member 73 is made of a material having a coefficient of restitution with the joint 27 lower than that of the connection member 72 so that the adhesion between the output member 71 and the joint 27 is improved as compared with the case where the connection member 72 directly contacts the joint 27. Preferably, it is configured.

  When the output member 71 moves forward by the injection motor 53, the contact member 73 contacts the joint 27. Therefore, the plunger 5 can be advanced by the injection motor 53. Further, the plunger 5 can be moved forward relative to the output member 71 by moving the piston rod 25 at a relatively high speed. Since the contact member 73 is in contact with the joint 27 over the entire circumference, a moment that tilts the joint 27 is suppressed.

  The guide mechanism 57 is preferably located on the side opposite to the cylinder device 7 with respect to the transmission mechanism 55. In this case, compared with the case where the guide mechanism 57 is positioned between the transmission mechanism 55 and the cylinder device 7, the nut 65 is moved closer to the piston rod 25 (the joint 27 and the abutting member 73) and the nut 65 and the piston rod are moved. The moment of tilting the nut 65 generated between the nut 65 and the nut 25 can be reduced, and the distance of the guide bar 67 with respect to the nut 65 can be appropriately set to suppress the tilt of the nut 65 appropriately.

  The attachment / detachment unit 13 includes, for example, a hook 74 and an actuator 75 that drives the hook 74.

  For example, the hook 74 is formed in an approximately L shape, and one end thereof is rotatably supported by the connecting member 72. The hook 74 is engaged with the engaged portion 27a formed in the joint 27 in the retracting direction of the plunger 5 ("ON" position) and the disengaged position ("" It is possible to move between the “OFF” position).

  When the hook 74 is turned off (disengaged), the plunger 5 can be moved forward relative to the output member 71. Further, when the hook 74 is turned on (engaged), the plunger 5 can be moved backward by the electric motor 53 for injection.

  The actuator 75 is constituted by, for example, an actuator that reciprocates (expands and contracts from another viewpoint). The actuator 75 is, for example, a linear motor, a pneumatic cylinder, or a hydraulic cylinder. The actuator 75 has one end side (for example, main body) supported by the connecting member 72 and the other end side (for example, movable portion) connected to the hook 74. The hook 74 is turned on or off by the reciprocating motion of the actuator 75.

(Control system)
Returning to FIG. 1, the control device 15 includes, for example, a CPU 77, a memory 79 such as a ROM or a RAM, an input circuit 81, and an output circuit 83. The CPU 77 executes a program stored in the memory 79, and outputs a control signal for controlling each unit via the output circuit 83 based on an input signal input via the input circuit 81.

  A signal is input to the input circuit 81 by, for example, an input device 85 that accepts a user input operation, an encoder 59 (FIG. 2), a servo driver 61 (FIG. 2), and a first position sensor that detects the position of the piston rod 25. 89, a second position sensor 91 (FIG. 2) for detecting the position of the guide bar 67, a servo valve 51, a head pressure sensor 93 for detecting the pressure of the head side chamber 21h, a rod pressure sensor 95 for detecting the pressure of the rod side chamber 21r, And an accumulator pressure sensor 97 that detects the pressure of the accumulator 35.

  The output circuit 83 outputs a signal, for example, a display 87 that displays information to the user, a servo driver 61, a servo valve 51, and a hydraulic pressure (not shown) that controls the introduction of pilot pressure to various valves. Circuit.

  The first position sensor 89 detects the position of the piston rod 25 with respect to the cylinder tube 21 and indirectly detects the position of the plunger 5. For example, the first position sensor 89 is fixed to or formed on the piston rod 25 and constitutes a linear encoder together with a scale portion (not shown) extending in the axial direction of the piston rod 25. The first position sensor 89 or the control device 15 can detect the speed by differentiating the detected position.

  The second position sensor 91 detects the position of the guide bar 67 with respect to the guide portion 69, and indirectly detects the position of the driven portion (the nut 65 or the output member 71) of the driving device 11. For example, the second position sensor 91 is fixed to or formed on the guide bar 67 and constitutes a linear encoder together with a scale portion (not shown) extending in the axial direction of the guide bar 67. The second position sensor 91 or the control device 15 can detect the speed by differentiating the detected position.

  The head pressure sensor 93 and the rod pressure sensor 95 indirectly detect the pressure applied to the molten metal by the plunger 5 by detecting the pressure in the head side chamber 21h and the rod side chamber 21r. The accumulator pressure sensor 97 is used for determining whether the accumulator 35 is completely filled.

(Operation of injection device)
FIG. 3 is a diagram for explaining the operation of the injection apparatus 1. In FIG. 3, the horizontal axis represents 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, the operations of the piston 23, the injection motor 53, the detachable portion 13, the servo valve 51, the pump motor 33, and the accumulator 35 are shown. In the lower part of FIG. 3, the load of the injection motor 53 is shown.

  “ON / OFF” of the servo valve 51 indicates a state in which the opening degree is controlled / a state in which the opening degree is opened or closed without being controlled. Further, “filling” of the accumulator 35 indicates a state in which the accumulator 35 can be filled (the filling does not have to be performed over the entire range “filled”).

  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 the low speed injection, the injection device 1 is in the state shown in FIGS. That is, the piston 23 and the nut 65 are located at an initial position such as a retreat limit. In this initial position, the contact member 73 of the output member 71 is in contact with the joint 27, and the hook 74 of the detachable portion 13 can be engaged with the joint 27. However, the engagement is not necessarily performed, and the engagement is released (OFF) in this embodiment. Further, the injection motor 53 is stopped. The pump electric motor 33 is stopped if the accumulator 35 is completely filled, and is driven if the filling is not completed. The servo valve 51 and the first check valve VLA to the fourth check valve VLD may be in an appropriate state as long as the discharge of the hydraulic fluid from the accumulator 35 is prohibited. For example, the servo valve 51 is closed. The first check valve VLA is self-closed without introducing pilot pressure, and the second check valve VLB and the third check valve VLC are closed with 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 15 performs screwing in the direction in which the nut 65 is advanced. The injection motor 53 is driven so that the shaft 63 rotates. The driving force of the nut 65 is transmitted to the joint 27 through the connecting member 72 and the contact member 73, and the plunger 5 and the piston rod 25 move forward. That is, low speed injection is performed by the driving force of the driving device 11.

  3 illustrates the case where the low-speed injection is performed in a state where the detachable portion 13 (hook 74) is turned off (disengaged), the detachable portion 13 may be turned on. In this case, for example, when multistage control including deceleration is performed, it is possible to prevent the plunger 5 from moving away from the output member 71 due to inertial force.

  During the low-speed injection, the servo valve 51 is fully opened, for example, and the third check valve VLC is stopped from introducing pilot pressure. Accordingly, the hydraulic fluid discharged from the rod side chamber 21r as the piston 23 moves forward is supplied to the head side chamber 21h whose volume increases as the piston 23 moves forward.

  The shortage of hydraulic fluid in the head side chamber 21h due to the difference in the pressure receiving area of the piston 23 between the rod side chamber 21r and the head side chamber 21h is replenished from the tank 29 via a flow path (not shown), for example. The second check valve VLB may be configured to be opened by introducing pilot pressure, and replenishment may be performed via the second flow path 43.

  The speed of the plunger 5 is controlled by adjusting the rotation speed of the injection motor 53. Specifically, the control device 15 feedback-controls the rotation speed of the injection motor 53 based on the speed of the plunger 5 detected by the second position sensor 91 (or the first position sensor 89).

  The filling of the accumulator 35 is terminated when the pump motor 33 is stopped (OFF) when the pressure of the accumulator pressure sensor 97 reaches a predetermined filling completion pressure. The capacity of the pump 31, the rotational speed of the pump motor 33 and / or the filling completion pressure, etc. are filled in the accumulator 35 at an appropriate time after the filling start of the accumulator 35 described later until the low-speed injection ends. It is set as appropriate.

(High-speed injection: t1 to t2)
When the position of the plunger 5 based on the detection value of the second position sensor 91 (or the first position sensor 89) reaches a predetermined high-speed switching position, the control device 15 introduces a pilot pressure that opens to the first check valve VLA. At the same time, the servo valve 51 is adjusted to an appropriate opening degree. Further, the control device 15 continues to turn off the attachment / detachment unit 13 (disengagement) after the low-speed injection, or turns off the attachment / detachment unit 13 that was ON in the low-speed injection.

  As a result, hydraulic fluid is supplied from the accumulator 35 to the head side chamber 21h via the first check valve VLA, and the piston 23, piston rod 25 and plunger 5 move forward at a relatively high speed. At this time, since the engagement of the detachable portion 13 is released, the plunger 5 or the like moves forward leaving the output member 71 and the nut 65 moving at a relatively low speed. Therefore, the drive device 11 does not become a load that prevents the plunger 5 or the like from moving forward. Then, the molten metal of the sleeve 3 is injected into the cavity 105 at a high speed.

  In addition, when the plunger 5 is driven by the cylinder device 7, the load of the injection motor 53 of the drive device 11 is lower than that during low-speed injection.

  The speed of the plunger 5 is controlled by adjusting the opening degree of the servo valve 51. The control device 15 may feedback control the opening degree of the servo valve 51 based on the speed of the plunger 5 detected by the first position sensor 89.

(Decelerated injection: t2 to t3)
When the molten metal is filled to some extent in the cavity 105, the plunger 5 receives a reaction force from the filled molten metal and decelerates, while the injection pressure increases rapidly. The operation of each part is the same as that during high-speed injection. However, in order to alleviate the impact at the time of filling, appropriate deceleration control such as reducing the opening degree of the servo valve 51 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 15 stops introducing the closing pilot pressure to the second check valve VLB. The pressure increase start condition is, for example, that the detection value of the injection pressure detected by the head pressure sensor 93 and the rod pressure sensor 95 has reached a predetermined value, or the detection of the plunger 5 detected by the first position sensor 89. The position has reached a predetermined position.

  When the introduction of the closing pilot pressure to the second check valve VLB is stopped, the rod side chamber 21r is set to the tank pressure. Then, the pressure in the head side chamber 21h increases until it becomes equal to the pressure in the accumulator 35, and the injection pressure reaches the final pressure. Further, the injection speed becomes 0 when the cavity 105 is completely filled with the molten metal. The third check valve VLC is self-closed by setting the rod side chamber 21r to the tank pressure, but a pilot pressure for closing may be introduced.

(Holding pressure: t4 to t6)
The control device 15 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 15 stops the introduction of the pilot pressure to be opened to the first check valve VLA and introduces the pilot pressure to be closed to the second check valve VLB. Thereby, the supply of the hydraulic pressure from the accumulator 35 to the head side chamber 21h 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 15 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.

(Driving of driven part: t5)
The pressure increase is started and the speed of the plunger 5 is decreased, and further, the pressure holding is started and the plunger 5 is stopped, so that the output member 71 continuously driven from the low speed injection by the driving device 11 is applied to the joint 27. catch up. In other words, the detachable portion 13 is in an engageable state. The time when the output member 71 reaches the joint 27 is preferably before the pressure holding is completed.

  When the control device 15 detects the arrival of the output member 71 to the joint 27 based on the detection values of the first position sensor 89 and the second position sensor 91, the control device 15 stops the injection motor 53.

  Note that the speed of the output member 71 from the start of high-speed injection until the output member 71 reaches the joint 27 may be equal to or different from the speed at the time of low-speed injection. Further, deceleration control may be appropriately performed so that the output member 71 does not give an impact to the plunger 5.

(Extrusion follow-up: t7 to t9)
After completion of the pressure holding, the control device 15 causes the mold clamping device (not shown) to open the mold, and pushes out the molded product from the fixed mold 101 by the extrusion device (not shown). At this time, the control device 15 drives the injection motor 53 in the direction in which the output member 71 is advanced, and pushes out the biscuits by the plunger 5.

  At this time, the flow of the hydraulic fluid may be the same as that at the time of low speed injection, for example. That is, the hydraulic fluid discharged from the rod side chamber 21r is returned to the head side chamber 21h via the third flow path 45, and the shortage of hydraulic fluid in the head side chamber 21h may be replenished from the tank 29.

  When the current (load) flowing through the injection motor 53 detected by the servo driver 61 exceeds a predetermined set value, the control device 15 advances the plunger 5 together with the cylinder device 7. Specifically, for example, the pilot pressure is introduced into the first check valve VLA, and the working fluid is supplied from the accumulator 35 to the head side chamber 21h. The hydraulic fluid in the rod side chamber 21r may be returned to the head side chamber 21h as in the high-speed injection, or may be discharged into the tank 29 as in the pressure increase.

  On the other hand, when the load detected by the servo driver 61 is less than the set value, the control device 15 advances the plunger 5 using only the injection motor 53 without using the cylinder device 7 together.

  In addition, it is determined whether or not the set value is equal to or greater than the set value in the trial operation, and it may be determined whether or not to use it uniformly for a plurality of subsequent molding cycles. This determination is performed, and the combination may be performed after the set value or more in each molding cycle or during the set value or more.

  Further, the combined use may be performed over the entire extrusion follow-up, or may be performed only in the initial stage when the load increases. Here, the initial stage of extrusion follow-up includes a range in which the plunger 5 starts moving forward and does not include a point in time when the plunger 5 stops moving forward. For example, the stroke of the plunger 5 in push-following Is a period corresponding to the first range of 1/5 to 1/2.

  FIG. 3 exemplifies the case where the cylinder device 7 is used in combination, and it is determined in advance that the cylinder device 7 is used together, and the discharge of the accumulator 35 is started simultaneously with the start of rotation of the injection motor 53. Moreover, the case where combined use is performed only in the initial stage (t7-t8) of extrusion follow-up is illustrated.

(Plunger retraction: t10 to t11)
The control device 15 is configured at an appropriate time after the output member 71 reaches the joint 27 (after t5), preferably after completion of the pressure holding (after t6), and more preferably at the start of extrusion follow-up (t7). , The detachable portion 13 is turned on (engaged). Then, when the extrusion follow-up is completed, the control device 15 drives the injection motor 53 in the direction in which the output member 71 is retracted. Thereby, the plunger 5 moves backward.

  The hydraulic fluid discharged from the head side chamber 21h as the piston 23 moves backward is recirculated to the rod side chamber 21r by introducing, for example, a pilot pressure that opens to the third check valve VLC and opening the servo valve 51. . Excess hydraulic fluid in the rod side chamber 21r is discharged to the tank 29 by, for example, stopping introduction of pilot pressure to the second check valve VLB. The hydraulic fluid discharged from the head side chamber 21h can be used for filling the accumulator 35.

(Accumulator filling: t9 to t11 to t1)
The filling of the accumulator 35 may be performed at an appropriate time except for high-speed injection in which the accumulator 35 is discharged, pressure increase and holding pressure, and extrusion follow-up in which the accumulator 35 may be discharged.

  For example, when the extrusion follow-up is completed (t9), the control device 15 starts driving the pump motor 33 and starts filling the accumulator 35. The first check valve VLA is self-closed. Further, the filling of the accumulator 35 is completed by the end of the low speed injection as described above.

  As described above, in the present embodiment, the injection device 1 includes the plunger 5, the cylinder device 7, the drive device 11, and the detachable portion 13. The plunger 5 can extrude the molding material into the cavity 105. The cylinder device 7 has a piston rod 25 connected to the plunger 5. The drive device 11 has driven parts (nut 65 and output member 71), and can drive the nut 65 and the like in a direction parallel to the piston rod 25. The detachable portion 13 can connect and release the piston rod 25, the nut 65, and the like for restricting relative advancement of the piston rod 25 with respect to the nut 65 and the connection. The control device 15 controls the cylinder device 7 and the drive device 11.

  Specifically, in the low-speed injection, the control device 15 is configured so that the driven portion (the output member 71 and the like) is in contact with the joint 27 fixed to the piston rod 25 in the forward direction. The plunger 5 is driven only by the driving force, and in high-speed injection, the driving force of the cylinder device 7 (driving force generated by supplying hydraulic fluid to the cylinder device 7) in a state where the connection by the detachable portion 13 is released. The plunger 5 is driven only by this, and the piston rod 25 is moved forward relative to the driven part. When the plunger is retracted, the plunger is driven by the driving force of the driving device 11 while being connected by the attaching / detaching part 13. Move 5 back.

  Therefore, in the high-speed injection, the forward speed of the plunger 5 is not limited to the speed of the driving device 11, and the high-speed injection is suitably performed. Further, since the low-speed injection and the plunger retreat are performed by the drive device 11, the amount of hydraulic fluid delivered to the cylinder device 7 by the hydraulic pressure source (pump 31 and / or accumulator 35) can be reduced.

  In particular, when the plunger 5 is retracted only by the driving force of the driving device 11 during the plunger retraction, there is no need to send hydraulic fluid to the cylinder device 7 by the hydraulic pressure source. As a result, for example, the burden on the hydraulic pressure source can be further reduced, and the accumulator 35 can be filled simultaneously with the retreat of the plunger to shorten the molding cycle.

  The control device 15 drives the plunger 5 only by the driving force of the cylinder device 7 in a state where the connection by the detachable portion 13 is released at least at the start of the pressure increase (in this embodiment, the whole pressure increase). From the start of pressure to the end of pressure retention (during pressure retention in this embodiment), the driven portion (output member 71 etc.) reaches a position where it can be connected to the piston rod 25 by the detachable portion 13. The cylinder device 7 and the drive device 11 are controlled.

  Therefore, the plunger can be retracted by the driving force of the driving device 11 over the entire stroke immediately after the pressure holding is completed. As a result, for example, the molding cycle can be shortened.

  The control device 15 drives the plunger 5 by the drive device 11 in the product extrusion follow-up, and when the load becomes a predetermined set value or more, drives the plunger 5 together with the cylinder device 7 and sets the value below the set value. In this case, the cylinder device 7 and the drive device 11 are controlled so as to drive the plunger 5 without using the cylinder device 7 together.

  Therefore, a necessary and sufficient pushing force can be obtained while suppressing the delivery of the hydraulic fluid from the hydraulic pressure source (pump 31 and / or accumulator 35).

  The injection device 1 further includes a pump 31 that can deliver hydraulic fluid, a pump electric motor 33 that drives the pump 31, and an accumulator 35 that can supply hydraulic fluid to the cylinder device 7. The pump 31 includes an accumulator. The hydraulic fluid is delivered only to 35.

  As described above, the pump 31 can be used exclusively for filling the accumulator 35, as described above, the plunger is retracted by the drive device 11 to reduce the necessity of sending hydraulic fluid from the hydraulic pressure source to the cylinder device 7. It depends on. Since the pump 31 is dedicated to filling the accumulator 35, the pump 31 and the pump motor 33 can be reduced in capacity, and the tank 29 can also be reduced in capacity.

  Furthermore, since the pump 31 is exclusively used for filling the accumulator 35, the pump 31 is a constant capacity pump in which the discharge amount in one cycle is not variable, and the pump motor 33 is a constant speed motor controlled by open loop. Can. As a result, an inexpensive electric motor and pump can be used.

  Further, since the amount of hydraulic fluid delivered from the hydraulic pressure source is small, the calorific value of the hydraulic device 9 is small, and an inexpensive air-cooled cooler 39 can be employed.

  The drive device 11 has a guide bar 67 extending in parallel with the piston rod 25 in the backward direction from the driven portion (the output member 71 and the like), and a guide portion 69 that guides the guide bar 67 so as to be movable in the axial direction. . Therefore, an unnecessary moment is suppressed from being applied to the nut 65 and the like, and the drive device 11 can operate smoothly. Further, since the guide bar 67 extends rearward and is in parallel with the cylinder device 7, the injection device 1 can be easily downsized.

  The detachable portion 13 connects and releases the connection between the piston rod 25 and the driven portion (such as the output member 71) by engaging and releasing the engagement of the hook 74 with the engaging member (joint 27). Therefore, it is possible to reliably connect and release the connection.

  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. 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 cylinder device is not limited to a single-acting type, and may be a pressure-increasing type. For example, the cylinder device includes a cylinder tube having a small diameter portion and a large diameter portion, an injection piston fixed to the piston rod and sliding on the small diameter portion, and a small diameter portion and a large diameter portion sliding on the rear side thereof. It may have a booster 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. The run-around circuit may not be provided, or the meter-in circuit may be configured instead of or in addition to the meter-out circuit.

  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 electric motor is not limited to the 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 piston rod without using a transmission mechanism. When the electric motor is a rotary type, the transmission mechanism that converts the rotation of the electric motor into translational motion is not limited to a screw mechanism, and may be a rack and pinion mechanism, for example. The drive device may be an electric cylinder (hybrid cylinder) in which an electric motor, a pump, and a cylinder device are unitized. Two or more driving devices may be provided.

  The detachable part is not limited to those exemplified in the embodiment. For example, the attaching / detaching unit may be connected and released by excitation and demagnetization of an electromagnet. The attaching / detaching portion has an engaging member that is urged and engaged by a spring, and the engagement is released by a relatively large force generated by a speed difference between the piston rod and the driven portion by high-speed switching, and the plunger retracts. The engagement may not be released by a relatively small force generated by the plunger speed. In this case, the control of the attaching / detaching unit itself by the control device is not necessary.

  As illustrated in the embodiment, the detachable part may be capable of restricting only the forward movement of the piston rod relative to the driven part, or may be relative to the driven part of the piston rod like an electromagnet. It may be possible to regulate both forward movement and backward movement. In addition, when the attachment / detachment portion can regulate both forward and backward movement of the piston rod relative to the driven portion, the drive device is connected with the attachment / detachment portion without providing the contact member. It is also possible to perform low speed injection by driving.

  A guide mechanism (such as a guide bar) for suppressing the inclination of the piston rod may be omitted. Further, the guide mechanism may be configured by another mechanism such as a slide table. The guide mechanism may be disposed closer to the cylinder device than the transmission mechanism such as a screw shaft, or may be disposed closer to the plunger than the cylinder device.

  Each member may be formed integrally or may be composed of a plurality of members. For example, two or more of the nut 65, the output member 71, and the guide bar 67 may be integrally formed. Further, for example, the member fixed to the piston rod with which the driven part comes into contact may be a member separate from the joint.

  As exemplified in the embodiment, the driving force of the cylinder device is exhibited only for high-speed injection, pressure increase and holding pressure (extrusion follow-up as necessary), and the driving force of the driving device is low-speed injection, plunger retraction and extrusion. It is preferable to be used only for following. However, the driving force of the cylinder device and the driving force of the driving device may be appropriately used in various processes.

  For example, after the driven portion catches up with the piston rod after high-speed injection, the driving force of the driving device may also be used for pressure increase and / or pressure holding. Further, for example, the extrusion following may be performed only by the cylinder device. In addition, for example, not only the drive device but also the cylinder device may be used for the plunger backward movement (for example, the cylinder device may be used over the entire stroke, or only part of the stroke may be the cylinder device and the others may be the drive device only). Etc.).

  Further, as exemplified in the embodiment, the pump is preferably dedicated to filling the accumulator. However, the pump is used to generate a driving force in the cylinder device, or a shortage of hydraulic fluid in the cylinder device ( For example, the hydraulic fluid may be used for delivering the hydraulic fluid in an amount that does not generate a driving force to the head side chamber in low-speed injection.

  DESCRIPTION OF SYMBOLS 1 ... Injection device, 5 ... Plunger, 7 ... Cylinder device, 9 ... Hydraulic device, 11 ... Drive device, 13 ... Detachable part, 25 ... Piston rod, 65 ... Nut (driven part), 105 ... Cavity.

Claims (10)

A plunger that pushes the molding material into the cavity;
A cylinder device having a piston rod coupled to the plunger;
A driving device having a driven part and capable of driving the driven part in a direction parallel to the piston rod;
A connection for restricting relative advancement of the piston rod and the driven portion relative to at least the driven portion of the piston rod, and a detachable portion capable of releasing the connection;
A control device for controlling the cylinder device and the driving device;
Have
The controller is
In the low-speed injection, at least one of regulation of the backward movement of the piston rod relative to the driven portion by the attaching / detaching portion and contact of the driven portion with respect to a member fixed to the piston rod in the forward direction. In the state where is made, the plunger is driven only by the driving force of the driving device out of the driving force of the driving device and the driving force of the cylinder device,
In high-speed injection, the plunger is driven only by the driving force of the cylinder device among the driving force of the driving device and the driving force of the cylinder device in a state where the connection by the detachable portion is released, and the piston Advance the rod relative to the driven part;
In the plunger retreat, the plunger is retracted by the driving force of the drive device in a state where the connection by the attaching / detaching portion is made.
An injection device for a molding machine that controls the cylinder device and the driving device. The control device controls the cylinder device and the driving device so that the plunger is retracted only by the driving force of the driving device out of the driving force of the driving device and the driving force of the cylinder device when the plunger is retracted. The injection device of the molding machine according to claim 1. The controller is
At least at the start of pressure increase, the plunger is driven only by the driving force of the cylinder device out of the driving force of the driving device and the driving force of the cylinder device in a state where the connection by the detachable portion is released,
Between the start of pressure increase and the end of pressure holding, so that the driven part reaches a position connectable with the piston rod by the detachable part,
The injection device for a molding machine according to claim 1, wherein the cylinder device and the driving device are controlled. The control device drives the plunger by the drive device in the product extrusion follow-up, and when the load becomes a predetermined set value or more, drives the plunger using the cylinder device together, and is less than the set value. The injection device for a molding machine according to any one of claims 1 to 3, wherein the cylinder device and the driving device are controlled so as to drive the plunger without using the cylinder device together. A pump capable of delivering hydraulic fluid;
A pump electric motor for driving the pump;
An accumulator capable of supplying hydraulic fluid to the cylinder device;
Further comprising
The injection device for a molding machine according to any one of claims 1 to 4, wherein the pump delivers hydraulic fluid only to the accumulator of the cylinder device and the accumulator. The pump is a constant capacity pump in which the discharge amount in one cycle is not variable,
The injection apparatus for a molding machine according to claim 5, wherein the pump motor is a constant-speed motor that is controlled in an open loop. The injection device for a molding machine according to claim 5 or 6, further comprising an air-cooled cooler for cooling the hydraulic fluid. The driving device includes:
A guide bar extending in parallel with the piston rod in a backward direction from the driven portion;
The injection device for a molding machine according to any one of claims 1 to 7, further comprising a guide portion that guides the guide bar so as to be movable in an axial direction thereof. The driving device includes:
A rotary injection motor;
The injection device for a molding machine according to any one of claims 1 to 8, further comprising: a transmission mechanism that converts rotation of the injection motor into translational motion and transmits the translation motion to the driven portion. The said detachable part performs the connection of the said piston rod and the said driven part, and the cancellation | release of the said connection by engagement with the engagement member of a hook, and engagement cancellation | release. Injection machine for molding machines.

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