JP5491270B2 - Injection machine for molding machine - Google Patents

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.

  Plunger for extruding molding material into cavity of mold, injection cylinder device for driving plunger, accumulator capable of supplying hydraulic fluid to injection cylinder device, and injection piston of injection cylinder device by converting rotation of electric motor into translational motion An injection device having a rack and pinion mechanism that transmits to a rod is known (Patent Document 1).

  The injection device of Patent Document 1 has a clutch in a rotation transmission path from the electric motor to the pinion. In the injection process, hydraulic fluid is supplied from the accumulator to the injection cylinder device, and the plunger advances. At this time, with the clutch disengaged, the electric motor is rotated in a direction to retract the plunger. And just before a plunger stops, a clutch is connected. Thus, the inertial force in the forward direction of the plunger or the like is canceled by the inertial force in the backward direction of the electric motor or the like, and the generation of surge pressure is suppressed. Patent Document 1 also discloses that the plunger is moved backward by an electric motor.

JP 2009-183964 A

  In Patent Document 1, suppression of the generation of surge pressure as described above is the main purpose of providing an electric motor and a rack and pinion mechanism. And the structure of a clutch etc. is suitable in light of the main purpose.

  However, since the electric motor and the rack and pinion mechanism can be used for various applications, various configurations are proposed in light of the various applications, and the technology of the injection device having the electric motor and the rack and pinion mechanism is enriched. It is preferred that

  An object of the present invention is to provide an injection apparatus for a molding machine that has an accumulator and a rack and pinion mechanism, and can achieve a variety of techniques.

  An injection device for a molding machine according to the present invention includes a plunger for extruding a molding material into a cavity of a mold, an injection piston rod connected to the plunger, an injection piston fixed to the injection piston rod, and a slide of the injection piston. An injection cylinder device having an injection cylinder tube that is movably accommodated, and an inside of the injection cylinder tube partitioned into an injection rod side chamber on the injection piston rod side and an injection head side chamber on the opposite side by the injection piston; An accumulator, a valve that controls the flow of hydraulic fluid between the accumulator and the injection head side chamber, a rack that is fixed to the injection piston rod and extends in the advancing and retreating direction of the plunger, and the rack An intermeshing pinion, an electric motor generating a driving force for rotating the pinion, and a front It prohibits transmission to the pinion of the rotation of the direction of advancing the plunger of the motor, having a one-way clutch that allows the transmission to the pinion of the rotation of the direction retracting the plunger of the motor.

  Preferably, in the injection step, the plunger is advanced by supplying hydraulic fluid from the accumulator to the injection head side chamber, and the electric motor is driven at a speed at which the one-way clutch is idled in the direction in which the plunger is advanced. After rotating and solidifying the molding material in the cavity, the electric motor is rotated in a direction for retracting the plunger, and the rotation is transmitted to the pinion via the one-way clutch so that the plunger is retracted. And a control device for controlling the electric motor and the valve.

  Preferably, the injection device is provided in a rotation transmission path from the electric motor to the one-way clutch, and is capable of changing a rotation speed ratio output to the one-way clutch side with respect to the rotation input from the electric motor side. The control device controls the transmission so that the speed ratio when the plunger is retracted is smaller than the speed ratio in high-speed injection, and the injection head is operated by retreating the plunger. The valve is controlled so that the hydraulic fluid discharged from the side chamber is supplied to the accumulator and the accumulator is accumulated.

Preferably, the injection cylinder device further includes a rack rod fixed to the injection piston and extending from the injection cylinder tube to the opposite side of the injection piston rod,
The rack is formed in a portion of the rack rod that is located outside the injection cylinder tube even when the plunger is advanced to a position where the filling of the molding material is completed.

  Preferably, the injection rod side chamber is filled with hydraulic fluid, and a run-around circuit that communicates the injection rod side chamber and the injection head side chamber, and an outflow amount of the hydraulic fluid from the injection rod side chamber can be controlled. At least one of the meter-out circuits is provided.

  Preferably, the rack is provided on the injection piston rod, and a part of the rack on the injection piston side is located at a position where the rack is moved in and out of the injection cylinder tube as the injection piston moves forward and backward. The injection rod side chamber is filled with gas.

  ADVANTAGE OF THE INVENTION According to this invention, it has an accumulator and a rack and pinion mechanism, and can provide the injection apparatus of the molding machine which can aim at diversification of a technique.

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 which shows typically an electrically-driven part including the cross section of the II-II arrow direction of FIG. The enlarged view in the one-way clutch vicinity of FIG. The figure which shows the injection pressure and injection speed of the injection apparatus of FIG. The schematic diagram which shows the structure of the principal part of the injection device which concerns on the 2nd Embodiment of this invention. The schematic diagram which shows the structure of the principal part of the injection device which concerns on the 3rd Embodiment of this invention. The schematic diagram which shows the structure of the principal part of the injection device which concerns on the 4th Embodiment of this invention. FIG. 8A and FIG. 8B are views showing a modification of the injection apparatus of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the second and subsequent embodiments, the same reference numerals as those of the already described embodiments are used for configurations that are the same as or similar to those of the already described embodiments, and illustrations and descriptions may be omitted.

<First Embodiment>
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 an injection sleeve 3 that communicates with the cavity 105, a plunger 5 that pushes molten metal into the cavity 105 within the injection sleeve 3, and an injection cylinder device 7 that drives the plunger 5. The injection device 1 includes a hydraulic unit 9 that drives the injection cylinder device 7 by a hydraulic driving method, an electric unit 11 that drives the injection cylinder device 7 by an electric driving method, a hydraulic unit 9 and an electric motor. And a control device 13 for controlling the unit 11.

  The injection 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 injection sleeve 3, and a plunger rod 5b that is fixed to the plunger tip 5a. When the molten metal is supplied into the injection sleeve 3 from the hot water supply port 3a formed in the injection sleeve 3, the plunger tip 5a slides (advances) in the injection sleeve 3 toward the cavity 105, whereby the molten metal is The cavity 105 is injected and filled.

  The injection cylinder device 7 includes an injection cylinder tube 15, an injection piston 17 that can slide inside the injection cylinder tube 15, and an injection piston rod 19 that is fixed to the injection piston 17 and extends from the injection cylinder tube 15. ing. The injection piston 17 and the injection piston rod 19 may be formed separately and fixed to each other, or may be formed integrally and fixed to each other.

  The injection cylinder tube 15 is, for example, a cylindrical body having a circular inner cross-sectional shape. The inside of the injection cylinder tube 15 is partitioned by an injection piston 17 into an injection rod side chamber 15r on the side from which the injection piston rod 19 extends and an injection head side chamber 15h on the opposite side. By selectively supplying hydraulic fluid to the injection rod side chamber 15r and the injection head side chamber 15h, the injection piston 17 slides in the injection cylinder tube 15.

  The injection cylinder device 7 is arranged coaxially with the plunger 5. The injection piston rod 19 is connected to the plunger 5 via a coupling. The injection cylinder tube 15 is fixedly provided to a mold clamping device (not shown). Accordingly, the plunger 5 moves forward or backward in the injection sleeve 3 by the movement of the injection piston 17 relative to the injection cylinder tube 15.

  The hydraulic part 9 includes an accumulator 21 that can supply hydraulic fluid to the injection cylinder device 7 and a servo valve 23 that controls the flow of hydraulic fluid between the accumulator 21 and the injection cylinder device 7.

  The accumulator 21 may be configured by an accumulator of an appropriate type such as a weight type, a spring type, a pneumatic type, a cylinder type, and a prada type. For example, the accumulator 21 is a pneumatic-type, cylinder-type, or prada-type accumulator, and accumulates pressure by compressing air held in the accumulator 21, and supplies hydraulic fluid by the accumulated pressure.

  The accumulator 21 is connected to the ejection head side chamber 15h. Accordingly, by discharging the accumulated hydraulic fluid of the accumulator 21, the hydraulic fluid can be supplied to the injection head side chamber 15h and the injection piston 17 can be advanced. Conversely, the accumulator 21 can be accumulated by retracting the injection piston 17 by the electric part 11 and pushing out the hydraulic fluid in the injection head side chamber 15 h to the accumulator 21.

  The servo valve 23 can adjust the flow rate steplessly by opening with an opening degree corresponding to the input voltage. The servo valve 23 can output a signal S2 corresponding to the degree of opening, and feedback control is performed based on the signal S2. The servo valve 23 is constituted by, for example, a flow rate control valve with pressure compensation. The servo valve 23 is driven by, for example, an electro-hydraulic system in which a solenoid (motor) and a hydraulic circuit are sequentially operated to drive the spool. The hydraulic circuit uses, for example, the pressure of the accumulator 21 as a pilot pressure.

  The servo valve 23 is provided in a flow path connecting the accumulator 21 and the ejection head side chamber 15h. Therefore, the servo valve 23 can control the flow rate of the hydraulic fluid supplied from the accumulator 21 to the injection head side chamber 15h to control the speed of the injection cylinder device 7, and constitutes a so-called meter-in circuit.

  The injection rod side chamber 15r is adapted to supply or discharge the hydraulic fluid as appropriate according to the change in capacity accompanying the movement of the injection piston 17. For example, the tank 22 is connected to the injection rod side chamber 15r.

  The motor unit 11 includes a rack 25 fixed to the injection piston 17 and a pinion 27 that can mesh with the rack 25.

  The rack 25 is provided on a rack rod 29. The rack rod 29 is fixed to the injection piston 17 and extends from the injection cylinder tube 15 to the side opposite to the injection piston rod 19. The injection piston 17 and the rack rod 29 may be formed separately and fixed to each other, or may be formed integrally and fixed to each other.

  The rack rod 29 is formed in, for example, a columnar shape having a smaller diameter than the injection piston 17 and is fixed so that the injection piston 17 and the shaft core coincide with each other. The diameter of the rack rod 29 may be larger or smaller than the diameter of the injection piston rod 19.

  The rack rod 29 is formed relatively long. For example, the rack rod 29 is formed to have a length exceeding twice the movable distance of the injection piston 17 relative to the injection cylinder tube 15. Therefore, even if the injection piston 17 is positioned at the forward limit, the portion of the rack rod 29 opposite to the injection piston 17 is positioned outside the injection cylinder tube 15. The rack 25 is provided in a portion of the rack rod 29 that is located outside the injection cylinder tube 15 even when the injection piston 17 is positioned at the forward limit.

  Although not particularly shown, the rack 25 is provided on the outer peripheral surface of the rack rod 29 and has a plurality of teeth arranged along the axial direction of the rack rod 29 (the advance and retreat direction of the injection piston 17). For example, the plurality of teeth are arranged over a length equivalent to the movable distance of the injection piston 17. The rack 25 may be provided on any of the upper surface, the side surface, and the lower surface of the rack rod 29. In this embodiment, the rack 25 is provided on the lower surface of the rack rod 29.

  The pinion 27 is arranged such that a direction orthogonal to the axial direction of the rack rod 29 (advancing and retreating direction of the injection piston 17) (the paper surface penetration direction in FIG. 1) extends in the rotation axis RA. The pinion 27 is formed in a generally disc shape, and has a plurality of teeth that are arranged along the outer peripheral surface and can mesh with the plurality of teeth of the rack 25, although not particularly illustrated. Therefore, the rack 25 can be moved forward by rotating the pinion 27 in one direction, and the rack 25 can be moved backward by rotating the pinion 27 in the other direction.

  FIG. 2 is a diagram schematically showing the electric motor unit 11 including a cross section in the direction of arrows II-II in FIG.

  The electric motor 11 includes a rotary electric motor 31, a transmission 33 to which rotation of the electric motor 31 is input, and a one-way clutch 35 provided between the transmission 33 and the pinion 27.

  The electric motor 31 may be a DC motor or an AC motor. Moreover, the electric motor 31 may be comprised by appropriate motors, such as an induction motor and a synchronous motor. The electric motor 31 is configured as a servo motor, for example, and constitutes a servo mechanism together with an encoder 39 that detects the rotation of the electric motor 31 and a servo driver (servo amplifier) 41 that supplies electric power to the electric motor 31.

  In the description of the operation described later, when the electric motor 31 is stopped, the electric motor 31 may be in a torque-free state, may be controlled to stop at a fixed position, and includes a brake. And a 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 electric motor 31 is stopped.

  The transmission 33 converts the input rotation of the electric motor 31 into rotation at an appropriate speed and outputs the rotation from the output shaft 33a. Further, the transmission 33 can change the speed ratio of the output rotation with respect to the input rotation. The transmission 33 may be a stepped transmission that includes a gear mechanism or the like, or may be a continuously variable transmission that includes a belt or the like. The speed ratio of the transmission 33 includes a speed ratio (reduction ratio) that reduces the rotation of the electric motor 31. The rotation of the electric motor 31 is decelerated and transmitted to the pinion 27, so that a large torque can be applied to the pinion 27.

  FIG. 3 is an enlarged view in the vicinity of the one-way clutch 35 of FIG.

  The one-way clutch 35 includes an inner ring 43 that rotates integrally with the output shaft 33a, a bearing 45 and a plurality of sprags 47 that are interposed between the inner ring 43 and the pinion 27. In the present embodiment, the pinion 27 is also used as the outer ring of the one-way clutch 35.

  The inner ring 43 is a generally annular member. The inner ring 43 is attached to the output shaft 33a by the keyway mechanism 49 so that the inner ring 43 can move in the direction of the rotation axis RA and cannot rotate about the rotation axis RA. However, the inner ring 43 can be completely fixed to the output shaft 33a, or the output shaft 33a can be used as the inner ring.

  The bearing 45 supports the load of the pinion 27 on the inner ring 43 while keeping the distance between the inner ring 43 and the pinion 27 constant, and allows relative rotation of the inner ring 43 and the pinion 27 about the rotation axis RA. The bearings 45 are constituted by ball bearings, for example, and are disposed on both sides in the direction of the rotation axis RA with respect to the inner ring 43 and the pinion 27.

  The plurality of sprags 47 are formed in the same shape as each other, are arranged along the outer periphery of the inner ring 43, and are held on the inner ring 43 by a holding member (not shown) so as to be rotatable around the rotation axis RA together with the inner ring 43. When the inner ring 43 and the pinion 27 are relatively rotated in one direction, the plurality of sprags 47 are engaged with the outer peripheral surface of the inner ring 43 and the inner peripheral surface of the pinion 27, and the rotation between the inner ring 43 and the pinion 27 is performed. Allow transmission. On the other hand, when the inner ring 43 and the pinion 27 rotate relative to each other, the plurality of sprags 47 slide with respect to the inner peripheral surface of the pinion 27 and prohibit transmission of rotation between the inner ring 43 and the pinion 27. To do. That is, the one-way clutch 35 idles.

  A specific structure related to the engagement and idling of the one-way clutch 35, for example, the shape of the plurality of sprags 47, the holding method of the plurality of sprags 47 to the inner ring 43, the biasing method of the plurality of sprags 47 to the inner ring 43, the inner ring 43 As for the shape of the outer peripheral surface, the shape of the inner peripheral surface of the pinion 27, etc., a known one-way clutch structure may be used as appropriate.

  The one-way clutch 35 rotates idly when the electric motor 31 is rotated in the direction for moving the plunger 5 forward, prohibits transmission of the rotation of the electric motor 31 to the pinion 27, and when the electric motor 31 is rotated in the direction for moving the plunger 5 backward. It is arranged so as to allow the transmission of rotation of the electric motor 31 to the pinion 27. Therefore, the electric motor 31 can only move the plunger 5 backward, and cannot move the plunger 5 forward.

  The output shaft 33a is supported by the bearing unit 51 so as to be able to withstand a large load so as to be rotatable around the rotation axis RA.

  Returning to FIG. 1, the control device 13 includes, for example, a CPU 61, a memory 63 such as a ROM or a RAM, an input circuit 65, and an output circuit 67. The CPU 61 executes a program stored in the memory 63, and outputs a control signal for controlling each unit via an output circuit 67 based on an input signal input via the input circuit 65.

  Signals are input to the input circuit 65 by, for example, an input device 69 that receives user input operations, an encoder 39 (FIG. 2), a position sensor 71 that detects the position of the injection piston rod 19, a servo valve 23, and an injection head side chamber. The first pressure sensor 73 detects the pressure of 15 h, and the second pressure sensor 75 detects the pressure of the accumulator 21.

  The output circuit 67 outputs a signal, for example, to the display 77 that displays information to the user, the servo driver 41, and the servo valve 23.

  The position sensor 71 detects the position of the injection piston rod 19 with respect to the injection cylinder tube 15 and indirectly detects the position of the plunger 5. For example, the position sensor 71 is provided on the injection piston rod 19 and constitutes a linear encoder together with a scale portion (not shown) extending in the axial direction of the injection piston rod 19. The position sensor 71 or the control device 13 can detect the speed by differentiating the detected position.

  The first pressure sensor 73 indirectly detects a pressure applied by the plunger 5 to the molten metal, such as a pressure (injection pressure) applied by the plunger 5 to the molten metal when the molten metal is injected into the cavity 105.

  The operation of the injection apparatus 1 having the above configuration will be described.

  FIG. 4 is a graph showing changes in injection pressure P and injection speed V in the injection apparatus 1.

  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 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. The plunger is advanced at a relatively high speed from the viewpoint. 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 advances in order to eliminate sink marks in the molded product. Specifically, it is as follows.

(Low speed injection)
Immediately before the start of the low-speed injection, the injection piston 17 is located at an initial position such as a backward limit as shown in FIG. The accumulator 21 has completed pressure accumulation. The servo valve 23 is closed. The electric motor 31 is stopped.

  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 injection sleeve 3, the control device 13 opens the servo valve 23 appropriately. Open in degrees.

  As a result, hydraulic fluid is supplied from the accumulator 21 to the injection head side chamber 15h, and the injection piston 17 moves forward. As a result, the molten metal in the injection sleeve 3 is injected into the cavity 105 by the plunger 5.

The speed of the plunger 5 is controlled by adjusting the opening degree of the servo valve 23, and as shown in FIG. 4, a relatively low speed injection speed _VL is set. Moreover, the injection pressure at this time is a relatively low pressure P _L. The control device 13 controls the speed of the plunger 5 by feedback control based on the detection value of the position sensor 71.

  Since the pinion 27 meshes with the rack 25 fixed to the plunger 5, the pinion 27 rotates when the plunger 5 moves forward. If the electric motor 31 (inner ring 43) is stopped, the one-way clutch 35 is engaged, and the inertial force of the electric motor 31 and the transmission 33 prevents the plunger 5 from moving forward.

  Therefore, the control device 13 rotates the electric motor 31 so that the inner ring 43 rotates faster than the pinion 27 in the direction in which the plunger 5 moves forward. As a result, the one-way clutch 35 is idling. As a result, the plunger 5 moves forward without being affected by the electric motor 31 and the transmission 33.

  Note that if the relative speed between the inner ring 43 and the pinion 27 in the idling state of the one-way clutch 35 is not preferable from the viewpoint of wear or the like, the rotational speed of the inner ring 43 is appropriately set so as not to exceed a predetermined allowable relative speed. Rotational speed.

(High speed injection)
When the position of the plunger 5 based on the detection value of the position sensor 71 reaches a predetermined high speed switching position, the control device 13 sets the opening degree of the servo valve 23 to an appropriate opening degree that is larger than the opening degree at the time of low speed injection.

As a result, the hydraulic fluid supplied from the accumulator 21 to the injection head side chamber 15h is increased, and the speed of the plunger 5 is set to a high speed injection speed _VH that is higher than the low speed injection speed _VL , as shown in FIG. . Moreover, the injection pressure at this time is at a higher pressure P _H from the injection pressure P _L at low speed injection. The control device 13 feedback-controls the speed of the plunger 5 as in the low-speed injection.

  In addition, the control device 13 maintains the rotation of the electric motor 31 so that the idling state of the one-way clutch 35 is maintained. However, since the rotational speed of the pinion 27 is switched to a high speed in accordance with the switching from the low speed injection to the high speed injection, the inner ring 43 and the pinion 27 are controlled so that the relative speed does not exceed a predetermined allowable relative speed. The rotation speed of 43 is switched to high speed. Switching of the rotational speed of the inner ring 43 is performed by at least one of switching of the rotational speed of the electric motor 31 and switching of the speed ratio of the transmission 33.

(Decelerated injection)
Deceleration injection is started by occurrence of an appropriate event. For example, the deceleration injection is started when the molten metal is filled to some extent in the cavity 105 and the plunger 5 receives a reaction force from the filled molten metal and decelerates. Alternatively, the deceleration injection is started by reducing the opening degree of the servo valve 23 when a predetermined deceleration start condition is satisfied, such as when the plunger 5 reaches a predetermined deceleration position. Alternatively, the event is started by the simultaneous occurrence of the events exemplified above.

In the deceleration injection operation, the injection speed is reduced from the high injection speed _VH to the speed Vd. However, the cavity 105, because it is filled to some extent the molten metal, the injection pressure is a pressure Pd rises from the high-speed injection pressure P _H in the high-speed injection.

  In addition, the control device 13 maintains the rotation of the electric motor 31 so that the idling state of the one-way clutch 35 is maintained. However, since the rotation speed of the pinion 27 is reduced as the injection speed is reduced, the rotation speed of the inner ring 43 is also reduced so that the relative speed between the inner ring 43 and the pinion 27 does not exceed a predetermined allowable relative speed. Is done. The inner ring 43 is decelerated by, for example, reducing the rotational speed of the electric motor 31. The speed ratio of the transmission 33 may be switched at an appropriate timing.

(Increase / hold pressure)
When a predetermined pressure increase start condition is satisfied, the control device 13 ends the speed control based on the position sensor 71. The opening degree of the servo valve 23 is set to a predetermined appropriate opening degree. The pressure increase start condition is, for example, that the detection value of the injection pressure detected by the first pressure sensor 73 has reached a predetermined value, or that the detection position of the plunger 5 has reached a predetermined position.

  The injection pressure reaches the final pressure Pmax via the pressure Pt. In addition, the injection speed becomes 0 after the speed Vt when the cavity 105 is completely filled with the molten metal. The control device 13 maintains the state where the injection pressure is the final pressure Pmax. During this time, the molten metal is cooled and solidified.

  Moreover, the control apparatus 13 makes the electric motor 31 a torque free state. However, the control device 13 may maintain the rotation of the inner ring 43 (the electric motor 31) at an extremely low speed as compared with the time of injection so that the idling state of the one-way clutch 35 is maintained. In addition, the control device 13 may temporarily rotate the electric motor 31 in the direction in which the plunger 5 is retracted immediately before the end of the pressure increase so as to suppress the generation of surge pressure.

(Plunger retract / accumulator filling)
The control device 13 rotates the electric motor 31 in the direction in which the plunger 5 is retracted when the molten metal is solidified (when a predetermined pressure holding end condition is satisfied). The holding pressure end condition is, for example, that a predetermined time has elapsed since the final pressure Pmax was obtained.

  When the electric motor 31 is rotated in the direction in which the plunger 5 is moved backward, the one-way clutch 35 is engaged, and the rotation of the electric motor 31 is transmitted to the pinion 27. Then, the plunger 5 to which the rack 25 meshing with the pinion 27 is fixed moves backward. As the plunger 5 moves backward, the injection piston 17 fixed to the plunger 5 also moves backward. The hydraulic fluid discharged from the injection head side chamber 15h as the injection piston 17 moves backward is supplied to the accumulator 21, and the accumulator 21 is accumulated. The servo valve 23 has an appropriate opening degree.

  The speed ratio of the transmission 33 is switched so that the rotation (input rotation) of the electric motor 31 is decelerated and transmitted to the inner ring 43. As a result, a large torque is applied to the plunger 5, and the accumulator 21 is suitably accumulated. The speed ratio of the output rotation to the input rotation at this time is smaller than that in the injection process (low-speed injection, high-speed injection, and deceleration injection).

(Preparation for the next cycle)
When the retraction of the plunger 5 and the filling of the accumulator 21 are completed, the control device 13 sets each part to the state before starting the low-speed injection described above. Specifically, the control device 13 closes the servo valve 23 and stops the electric motor 31.

  According to the above embodiment, the injection device 1 of the die casting machine DC1 includes the plunger 5, the injection cylinder device 7, the accumulator 21, and the servo that controls the flow of hydraulic fluid between the accumulator 21 and the injection head side chamber 15h. A valve 23, a rack 25 that is fixed to the injection piston rod 19, extends in the forward / backward direction of the plunger 5, a pinion 27 that meshes with the rack 25, an electric motor 31 that generates a driving force for rotating the pinion 27, and an electric motor And a one-way clutch 35 that prohibits transmission of rotation of the electric motor 31 in the direction of moving forward the plunger 5 to the pinion 27 and allows transmission of rotation of the electric motor 31 in the direction of moving back the plunger 5 to the pinion 27.

  Accordingly, the plunger 5 can be moved backward by the electric motor 31 and, at the time of advancement of the plunger 5, the electric motor 31 is rotated at a speed at which the one-way clutch 35 idles in the direction in which the plunger 5 moves forward. The influence on the forward movement can be suppressed. When the one-way clutch 35 is not provided, in order to suppress the influence of the electric motor 31 on the forward movement of the plunger 5, the electric motor 31 must be synchronously controlled with the servo valve 23, and the control becomes complicated. In the present embodiment, the speed of the electric motor 31 may be set to an appropriate speed as long as the speed of the inner ring 43 is higher than the speed of the pinion 27, so that the control is simplified.

  In addition, since the injection device of Patent Document 1 requires that the electric motor be rotated in the direction in which the plunger is moved backward while the plunger is moved forward, a one-way clutch is used as a clutch between the electric motor and the plunger. Is not possible.

  The injection device 1 further includes a transmission 33 that is provided in a rotation transmission path from the electric motor 31 to the one-way clutch 35 and that can change a rotation speed ratio output to the one-way clutch 35 side with respect to the rotation input from the electric motor 31 side. Have. The control device 13 controls the transmission 33 so that the speed ratio when the plunger 5 is retracted is smaller than the speed ratio in the high-speed injection, and the hydraulic fluid discharged from the injection head side chamber 15h when the plunger 5 is retracted. The servo valve 23 is controlled so as to be supplied to the accumulator 21 and to accumulate pressure in the accumulator 21.

  Therefore, during high-speed injection, an increase in the rotational speed of the motor 31 for idling the one-way clutch 35 is suppressed, and a large torque is applied to the pinion 27 when accumulator 21 is accumulated by retreating plunger 5. Can do.

  The injection cylinder device 7 further includes a rack rod 29 that is fixed to the injection piston 17 and extends from the injection cylinder tube 15 to the side opposite to the injection piston rod 19. The rack 25 is formed in a portion of the rack rod 29 that is located outside the injection cylinder tube 15 even when the plunger 5 has advanced to a position where the filling of the molding material is completed. Therefore, there is no need to provide a configuration for sealing the ejection head side chamber 15h while allowing the rack 25 to enter and exit the ejection head side chamber 15h, and the configuration is simplified.

  In the above embodiment, the die casting machine DC1 is an example of the molding machine of the present invention, the fixed mold 101 and the moving mold 103 are examples of the mold of the present invention, and the molten metal is the molding material of the present invention. The servo valve 23 is an example of the valve of the present invention.

<Second Embodiment>
FIG. 5 is a diagram illustrating a main part of the injection apparatus 201 according to the second embodiment.

  The structure of the injection device 201 is that a hydraulic circuit between the accumulator 21 and the injection cylinder device 207 corresponds to the point that the injection cylinder device 207 has a pressure increase function and the addition of the pressure increase function. The changed point is different from the configuration of the injection device 1 of the first embodiment. Specifically, it is as follows.

  The injection cylinder device 207 includes a pressure increasing cylinder tube 216 and a pressure increasing piston 218 slidably accommodated in the pressure increasing cylinder tube 216 in addition to the configuration of the injection cylinder device 7 of the first embodiment. doing.

  The pressure-increasing cylinder tube 216 has a small-diameter cylinder portion 216a communicating with the injection head side chamber 15h, and a large-diameter cylinder portion 216b that is connected to the small-diameter cylinder portion 216a and has a larger diameter than the small-diameter cylinder portion 216a.

  The pressure-increasing piston 218 has a small-diameter piston portion 218a that can slide the small-diameter cylinder portion 216a, and a large-diameter piston portion 218b that is fixed to the small-diameter piston portion 218a and can slide the large-diameter cylinder portion 216b. ing.

  The inside of the large-diameter cylinder part 216b is partitioned by the large-diameter cylinder part 216b into a front chamber 216r on the side from which the small-diameter piston part 218a projects and a rear chamber 216h on the opposite side.

  When the front chamber 216r is depressurized, due to the difference between the area of action of the small diameter piston part 218a in the small diameter cylinder part 216a and the area of action of the large diameter piston part 218b in the rear side chamber 216h, the pressure increasing piston 218 is A pressure higher than the pressure received from the hydraulic fluid in the rear chamber 216h can be applied to the hydraulic fluid in the small diameter cylinder portion 216a (injection head side chamber 15h). That is, the injection cylinder device 207 has a pressure increasing function.

  The front chamber 216r is configured so that the hydraulic fluid is supplied or discharged as appropriate according to the change in the capacity accompanying the movement of the pressure increasing piston 218, similarly to the injection rod side chamber 15r.

  In the hydraulic pressure unit 209, the flow path connecting the accumulator 21 and the injection cylinder device 207 branches on the injection cylinder device 207 side with respect to the servo valve 23 to the small diameter cylinder portion 216a (injection head side chamber 15h) and the rear chamber 216h. It is connected. Each branched flow path is provided with a first check valve VLA and a second check valve VLB (hereinafter simply referred to as “check valve VL”, which may not be distinguished from each other).

  The check valve VL is a pilot check valve (pilot check valve). When the pilot pressure is not introduced, the check valve VL allows the flow of hydraulic fluid from the accumulator 21 to the injection cylinder device 7 and prohibits the flow on the opposite side. The check valve VL prohibits bidirectional flow by introducing a closed pilot pressure, and allows bidirectional flow by introducing an open pilot pressure.

  The pilot pressure is introduced into the check valve VL by controlling a hydraulic circuit (not shown) by the control device 13 (see FIG. 1). Moreover, as a pilot pressure, the pressure of the accumulator 21 is utilized, for example.

  The operation of the injection apparatus 201 is as follows.

(Low speed injection)
Immediately before the start of low-speed injection, the pressure-increasing piston 218 is located at an initial position such as a backward limit. The check valve VL is closed by introducing pilot pressure. About the state of a structure other than that, it is the same as that of 1st Embodiment.

  When a predetermined low-speed injection start condition is satisfied, the control device 13 opens the servo valve 23 with an appropriate opening degree as in the first embodiment. Further, the introduction of the closing pilot pressure to the first check valve VLA is stopped. Thus, similarly to the first embodiment, low speed injection is performed by supplying the working fluid from the accumulator 21 to the injection head side chamber 15h. Note that the one-way clutch 35 is idled as in the first embodiment.

(High-speed injection and deceleration injection)
This is the same as in the first embodiment, and a description thereof will be omitted. Note that the check valve VL maintains a state in low-speed injection.

(Increase / hold pressure)
When a predetermined pressure increase start condition is satisfied, the control device 13 stops introducing the closing pilot pressure to the second check valve VLB. Thereby, the hydraulic fluid is supplied from the accumulator 21 to the rear chamber 216h, and the pressure increasing function by the pressure increasing piston 218 described above is exhibited.

  The first check valve VLA is self-closed when the pressure of the small-diameter cylinder portion 216a becomes higher than the pressure of the accumulator 21 by the pressure increasing function. However, a pilot pressure for closing the first check valve VLA may be introduced. The speed control based on the position sensor 71 is terminated, the opening degree of the servo valve 23 is set to a predetermined appropriate opening degree, the motor 31 is set to be torque free, etc. This is the same as the embodiment.

(Plunger retract / accumulator filling)
After completion of the pressure holding, the control device 13 introduces a pilot pressure that opens to the second check valve VLB. The servo valve 23 has an appropriate opening degree. Then, similarly to the first embodiment, the control device 13 rotates the electric motor 31 in the direction in which the plunger 5 is retracted, and also decelerates the rotation of the electric motor 31 and transmits the transmission 33 to the inner ring 43. Switch.

  Thereby, like the first embodiment, the plunger 5 and the injection piston 17 retreat. Further, the pressure in the small diameter cylinder portion 216a increases, and the pressure increasing piston 218 moves backward. The hydraulic fluid discharged from the rear chamber 216h with the movement of the pressure increasing piston 218 is supplied to the accumulator 21, and the accumulator 21 is accumulated.

  When the pressure-increasing piston 218 reaches the backward limit, the control device 13 introduces a pilot pressure to be closed to the second check valve VLB and introduces a pilot pressure to be opened to the first check valve VLA. In addition, the control device 13 continues to rotate the electric motor 31 to retract the plunger 5 and the injection piston 17.

  As a result, as in the first embodiment, the injection piston 17 moves to the retreat limit, and the hydraulic fluid discharged from the injection head side chamber 15h (small diameter cylinder portion 216a) with the movement of the injection piston 17 is accumulated in the accumulator 21. And the accumulator 21 is pressure-accumulated.

  Note that the fact that the pressure-increasing piston 218 has reached the backward limit may be appropriately detected. For example, it is possible to detect that the detected pressure of the first pressure sensor 73 has reached a predetermined pressure or that the speed detected by the position sensor 71 has been reduced to a predetermined speed.

  First, the first check valve VLA is opened, the accumulator 21 is accumulated by retreating the injection piston 17, and then the first check valve VLA is closed and the second check valve VLB is opened to increase the pressure increasing piston. It is also possible to accumulate pressure in the accumulator 21 by retreating 218.

(Preparation for the next cycle)
When the retraction of the plunger 5 and the filling of the accumulator 21 are completed, the control device 13 sets each part to the state before starting the low-speed injection described above.

  According to the second embodiment described above, the same effect as in the first embodiment can be obtained.

<Third Embodiment>
FIG. 6 is a diagram illustrating a main part of the injection apparatus 301 according to the third embodiment.

  The configuration of the injection device 301 is different from the configuration of the injection device 1 of the first embodiment in the arrangement position of the rack 25 and the pinion 27 and the portion related to the injection rod side chamber 15r of the hydraulic pressure unit 309. Specifically, it is as follows.

  In the injection device 301, the rack rod 29 is not provided, and the rack 25 is provided on the injection piston rod 319. Corresponding to the arrangement of the rack 25, the pinion 27 is arranged on the front side of the injection cylinder tube 15.

  The length of the rack 25 is, for example, the same as the movable distance of the injection piston 17 relative to the injection cylinder tube 15 as in the first embodiment. When the injection piston 17 is located at the retreat limit, the rack 25 has a part on the plunger 5 side located outside the injection cylinder tube 15 and meshes with the pinion 27, and the remaining part (part on the injection piston side). ) Is accommodated in the injection cylinder tube 15. The rack 25 may be provided on any of the upper surface, the side surface, and the lower surface of the injection piston rod 319, but FIG. 6 illustrates the case where the rack 25 is provided on the lower surface.

  In addition, the structure of the electrically-driven part 311 of 3rd Embodiment is the same as the structure shown in FIG.2 and FIG.3. However, in FIGS. 2 and 3, the rack rod 29 is replaced with an injection piston rod 319.

  The hydraulic unit 309 does not have the tank 22. Further, the injection rod side chamber 15r is not filled with hydraulic fluid, and gas (for example, air) is introduced or discharged in accordance with the change in capacity accompanying the movement of the injection piston 17. A relatively small amount of hydraulic fluid may be present in the injection rod side chamber 15r for the purpose of lubricating the injection piston 17 and the injection cylinder tube 15 or the like.

  The operation of the injection device 301 is substantially the same as in the first embodiment. However, as described above, gas is introduced or discharged in the injection rod side chamber 15r as the injection piston 17 moves.

  According to the above third embodiment, the same effect as in the first embodiment can be obtained.

  Further, in the third embodiment, the rack 25 is provided on the injection piston rod 319, and a part of the rack 25 on the injection piston 17 side is in relation to the injection cylinder tube 15 as the injection piston 17 advances and retreats. The injection rod side chamber 15r is provided at a position where it is taken in and out, and is filled with gas.

  Therefore, there is no need to provide the rack rod 29. Further, the injection piston rod 319 can be approximately the same length as the injection piston rod 19 of the first embodiment. Thus, the configuration is reduced in size. Further, it is not necessary to provide a configuration for sealing the injection rod side chamber 15r while allowing the rack 25 to enter and exit the injection rod side chamber 15r, and the configuration is simplified.

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

  The configuration of the injection device 401 is a combination of the configuration of the injection device 301 of the third embodiment with the configuration related to the pressure increasing function of the second embodiment.

  However, the pressure-increasing cylinder tube 416 of the injection cylinder device 407 of the fourth embodiment is directly connected directly behind the injection cylinder tube 15, and the small-diameter cylinder portion 216a in the second embodiment is omitted. The small diameter piston portion 218a is slidably inserted into the injection head side chamber 15h. Note that the inside of the pressure-increasing cylinder tube 416 is partitioned into a front chamber 416r and a rear chamber 416h by a large-diameter piston portion 218b, as in the second embodiment.

  Like the injection rod side chamber 15r of the third and fourth embodiments, the front chamber 416r is appropriately supplied or discharged with a gas (for example, air) according to a change in the capacity accompanying the movement of the pressure increasing piston 218. It has become. However, like the front chamber 216r of the second embodiment, the front chamber 416r may be configured to supply or discharge the hydraulic fluid as appropriate.

  The operation of the injection device 401 is substantially the same as the operation of the injection device 201 of the second embodiment. However, as described above, in the injection rod side chamber 15r and the front side chamber 416r, gas is introduced or discharged as the injection piston 17 and the pressure increasing piston 218 move.

  According to the above fourth embodiment, the same effect as in the first embodiment can be obtained.

  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 hydraulic part is not limited to that of the embodiment, and a flow path and a valve may be provided as appropriate.

  For example, as shown in FIG. 8A, in the first embodiment, a meter-out circuit may be configured by providing a servo valve 23 that can control the flow rate of the hydraulic fluid discharged from the injection rod side chamber 15r. . The meter-out circuit may be provided in place of the meter-in circuit, or may be used in combination with the meter-in circuit.

  Further, for example, as shown in FIG. 8B, in the first embodiment, a communication flow path 514 that connects the injection rod side chamber 15r and the injection head side chamber 15h is provided. A run-around circuit capable of returning the hydraulic fluid discharged from the cylinder chamber to the other cylinder chamber may be configured.

  In this case, the tank 22 can be omitted, and the required amount of hydraulic fluid is reduced. When the run-around circuit is provided, the pressure receiving area of the injection piston 17 in the injection head side chamber 15h is set larger than the pressure receiving area of the injection piston 17 in the injection rod side chamber 15r.

  The meter-in circuit and the run-around circuit shown in FIGS. 8A and 8B may be applied not only to the first embodiment but also to other embodiments. A servo valve 23 may be provided in the communication channel 514, and a meter-in circuit and a run-around circuit may be combined.

  Although the present invention makes it possible to omit the tank and the pump from the hydraulic part, a tank and a pump may be provided.

  The rack provided on the rack rod may be taken in and out of the injection cylinder tube, and the rack provided on the injection piston rod may not be accommodated in the injection cylinder tube. When the rack provided on the injection piston rod is taken in and out of the injection rod side chamber, the injection rod side chamber may be filled with the working fluid.

  Since the plunger stops when the filling of the molding material into the cavity is completed, the injection piston does not always move to the forward limit with respect to the injection cylinder tube. Therefore, in order to prevent the rack provided on the rack rod from entering the injection cylinder tube, the rack is not necessarily provided in a portion located outside the injection cylinder tube when the injection piston is positioned at the forward limit. There is no need. The rack may be formed in a portion located outside the injection cylinder tube even when the plunger is advanced to the position where the filling of the molding material is completed. It may be a portion located outside the injection cylinder tube when the plunger stops during idle driving.

  The number of racks and pinions may be provided as appropriate. As shown by a two-dot chain line in FIG. 1, a plurality of racks and pinions may be provided for one rack rod. Further, a rack and a pinion may be provided on both the injection piston rod and the rack rod.

  The inner ring of the one-way clutch may be rotated at a constant speed from the low speed injection to the deceleration injection. In other words, in the injection process, the rotation speed of the motor and the speed ratio of the transmission may be constant.

  The transmission mechanism that transmits the rotation of the electric motor to the pinion may be appropriately configured. For example, the transmission may be omitted, and a reduction gear or the like may be provided as appropriate.

  In the case where a transmission is provided, the speed ratio of the rotation output from the transmission with respect to the rotation input to the transmission only needs to be at least smaller than the speed ratio at the time of high-speed injection. For example, the speed ratio during deceleration injection may be equal to the speed ratio during plunger retraction.

  DESCRIPTION OF SYMBOLS 1 ... Injection device, 5 ... Plunger, 7 ... Injection cylinder device, 15 ... Injection cylinder tube, 15h ... Injection head side chamber, 15r ... Injection rod side chamber, 17 ... Injection piston, 19 ... Injection piston rod, 21 ... Accumulator, 23 ... Servo valve (valve), 25 ... rack, 27 ... pinion, 31 ... electric motor, 35 ... one-way clutch, 101 ... fixed die (die), 103 ... moving die (die), 105 ... cavity.

Claims (6)

A plunger that pushes the molding material into the mold cavity;
An injection piston rod connected to the plunger, an injection piston fixed to the injection piston rod, and an injection cylinder tube that slidably accommodates the injection piston, and the inside of the injection cylinder tube is the injection piston An injection cylinder device partitioned into an injection rod side chamber on the injection piston rod side and an injection head side chamber on the opposite side thereof,
An accumulator,
A valve for controlling the flow of hydraulic fluid between the accumulator and the ejection head side chamber;
A rack that is fixedly provided with respect to the injection piston rod and extends in the advancing and retreating direction of the plunger;
A pinion meshing with the rack;
An electric motor that generates a driving force for rotating the pinion;
A one-way clutch that prohibits transmission of rotation of the electric motor in the direction of moving forward the plunger to the pinion and allows transmission of rotation of the electric motor in the direction of moving backward of the plunger to the pinion;
An injection device for a molding machine. In the injection step, the plunger is advanced by supplying hydraulic fluid from the accumulator to the injection head side chamber, and the electric motor is rotated at a speed at which the one-way clutch runs idle in the direction in which the plunger is advanced, After the molding material in the cavity is solidified, the electric motor is rotated in the direction in which the plunger is retracted, and the rotation is transmitted to the pinion via the one-way clutch so that the plunger is retracted. The injection device for a molding machine according to claim 1, further comprising a control device that controls the valve. A transmission that is provided in a rotation transmission path from the electric motor to the one-way clutch, and capable of changing a rotation speed ratio output to the one-way clutch with respect to the rotation input from the electric motor;
The control device controls the transmission so that the speed ratio when the plunger is retracted is smaller than the speed ratio in high-speed injection, and the operation is discharged from the injection head side chamber when the plunger is retracted. The injection device for a molding machine according to claim 2, wherein the valve is controlled so that liquid is supplied to the accumulator and pressure accumulation in the accumulator is performed. The injection cylinder device further includes a rack rod fixed to the injection piston and extending from the injection cylinder tube to the opposite side of the injection piston rod;
The said rack is formed in the part located outside the said injection cylinder tube, when the said plunger advances to the position which completes filling of a molding material among the rods for racks. An injection device for a molding machine according to claim 1. The injection rod side chamber is filled with hydraulic fluid,
The at least one of the run-around circuit which connects the said injection rod side chamber and the said injection head side chamber, and the meter-out circuit which can control the outflow amount of the hydraulic fluid from the said injection rod side chamber is provided. Molding machine injection equipment. The rack is provided on the injection piston rod, and a portion of the rack on the injection piston side is provided at a position where the injection piston tube moves in and out with respect to the injection piston.
The injection device for a molding machine according to any one of claims 1 to 3, wherein the injection rod side chamber is filled with gas.

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