JP2017113963A - Injection molding machine, brake device and brake circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine capable of reducing the cycle time of an injection molding step or improving the accuracy of a holding position of a movable part; and a brake device and a brake circuit capable of switching between a brake holding state and a brake released state in a short time.SOLUTION: An injection molding machine comprises: a movable mechanism driven in a part of the injection molding step; a motor for driving the movable mechanism; a mover for contacting an object to be braked to brake the movable mechanism; an energizing member and an excitation coil (733) for displacing the mover; circulating sections (742 and 743) including a rectifier element (745), a voltage generation part (747) and a switch (137) and capable of circulating current between the excitation coil and the circulating section. When the electromagnetic force of the excitation coil is released, an AC voltage input is intercepted and the path of the circulating section is changed into a path including the voltage generation part from a path without including the voltage generation part.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an injection molding machine, a brake device, and a brake circuit.

  The injection molding machine includes a mold clamping device that performs mold opening, mold clamping, and mold closing, an injection device that injects a molding material into the mold, an ejector device that ejects a molded product in the mold, and the like. The mold clamping device, the injection device, and the ejector device include a movable mechanism and a motor for moving each part. Moreover, an injection molding machine may be equipped with the plasticizing movement apparatus which conveys components, such as an injection apparatus. The plasticizing movement device includes a movable mechanism and a motor for conveying the object. As such a motor, a motor having a brake device may be employed (see, for example, Patent Document 1). As a typical brake device, an electromagnetic brake that generates a braking force using an electromagnetic force is used.

  The electromagnetic brake includes an exciting coil that generates electromagnetic force and a brake circuit that drives the exciting coil to flow current. The brake circuit is generally provided with a free-wheeling diode connected in parallel with the exciting coil. When the drive of the exciting coil is stopped, it is avoided that a large amount of back electromotive force is generated in the exciting coil due to a current flowing between the refluxing diode and the exciting coil.

  Patent Document 2 discloses a technique of an automatic voltage regulator for a synchronous generator using a field coil. This document shows that when the drive of the field coil is stopped, the current flowing back to the field coil by switching the current path is caused to flow through the resistor, so that the current of the field coil is quickly attenuated. Yes.

JP 2005-199449 A JP 2001-298996 A

  In a brake device mounted on a conventional injection molding machine, it takes a relatively long time for the current flowing through the exciting coil to attenuate when the driving of the exciting coil is stopped. For this reason, a delay has occurred when the state is switched from brake release to brake holding.

  When there is a delay in the switching of the state of the brake device, there is a problem that one cycle time of the injection molding process becomes long when an operation step of the brake device is included in a part of the injection molding process. If the cycle time of one time is slightly increased, a large time loss occurs when a large number of molded articles are continuously manufactured.

  Further, if there is a delay in switching the state of the brake device, there is a problem that the accuracy of the position where the movable portion is held is lowered when the brake device is used to hold the movable portion of the injection molding machine in a stopped state. . Or the subject that the operativity at the time of hold | maintaining a movable part falls arises. For example, in a vertical injection molding machine in which the injection device moves up and down, the injection device may be stopped and held at an upper standby position. In this case, if there is a delay before the brake device is activated, the injection device is slightly lowered from the standby position by its own weight, and cannot be held at a desired position.

  An object of this invention is to provide the injection molding machine which can aim at reduction of the cycle time of an injection molding process, or improvement of the precision of the holding position of a movable part. Another object of the present invention is to provide a brake device and a brake circuit that can perform switching from the brake holding state to the brake release state or vice versa in a short time.

The injection molding machine according to the present invention is
A movable mechanism driven in part of the injection molding process;
A motor for driving the movable mechanism;
A mover that contacts the braking object and brakes the movable mechanism;
A biasing member that generates a biasing force for moving the mover;
An exciting coil that generates electromagnetic force and moves the mover in a direction that opposes the biasing force;
A first switch for switching between AC voltage input and cutoff;
A rectifier that rectifies the input AC voltage and supplies a drive voltage to the excitation coil;
A reflux unit having a rectifying element, a voltage generation unit, and a second switch, and capable of returning a current to and from the excitation coil;
With
When releasing the electromagnetic force of the exciting coil, the first switch cuts off the input of the AC voltage, and the second switch passes the path of the return part from the path not including the voltage generator. It is comprised so that it may change to the path | route containing a generation | occurrence | production part.

The brake device according to the present invention includes:
A mover that moves and contacts the object to be braked;
A biasing member that generates a biasing force for moving the mover;
An exciting coil that generates electromagnetic force and moves the mover in a direction that opposes the biasing force;
A rectifying unit that rectifies an alternating voltage and supplies a driving voltage to the exciting coil;
A reflux unit having a rectifying element and a voltage generator, and capable of returning a current to and from the excitation coil;
With
When the electromagnetic force of the exciting coil is released, the input of the AC voltage is interrupted, and the path of the return part is changed from a path not including the voltage generator to a path including the voltage generator. Configured.

The brake circuit according to the present invention is
This is a brake circuit that drives a brake mechanism that holds or releases braking by moving a mover applied with an urging force by an urging member in a direction opposite to the urging force by an electromagnetic force generated by an exciting coil. And
A rectifying unit that rectifies an alternating voltage and supplies a driving voltage to the exciting coil;
A reflux unit having a rectifying element and a voltage generator, and capable of returning a current to and from the excitation coil;
With
When the electromagnetic force of the exciting coil is released, the input of the AC voltage is interrupted, and the path of the return part is changed from a path not including the voltage generator to a path including the voltage generator. Configured.

  The injection molding machine according to the present invention can reduce the cycle time of the injection molding process or improve the accuracy of the holding position of the movable part. According to the brake device and the brake circuit of the present invention, switching from the brake holding state to the brake releasing state or vice versa can be performed in a short time.

It is a block diagram which shows the control system of the injection molding machine which concerns on embodiment of this invention. It is a side view which shows the mechanism system of the injection molding machine which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the motor for ejection and brake mechanism which concern on embodiment of this invention. It is a circuit diagram showing an example of a brake circuit concerning an embodiment of the invention. It is a graph which shows the coil voltage (a) and exciting current (b) of the brake circuit of FIG. 4, and the coil voltage (c) and exciting current (d) of the conventional brake circuit. It is a circuit diagram showing the 1st modification of a brake circuit concerning an embodiment of the invention. It is a circuit diagram showing the 2nd modification of a brake circuit concerning an embodiment of the invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a control system of an injection molding machine according to an embodiment of the present invention.

  An injection molding machine 1 according to an embodiment of the present invention includes an injection device 11, a plasticizing movement device 20, a mold clamping device 12, an ejector device 71, a safety door lock device 99, servo drivers 131 to 135, a converter circuit 110, and a controller. 121, an operation unit 122, and the like. The servo drivers 131 to 135 are provided with inverter circuits 111 to 115, respectively.

  The injection device 11 melts and injects the molding material. The injection device 11 is provided with a metering motor 83 that adjusts the amount of molding material input, and an injection motor 86 that adjusts the discharge amount of the molding material. The metering motor 83 is a servo motor and is driven by a servo driver 131 based on a command from the controller 121. The injection motor 86 is also a servo motor. The injection motor 86 is driven by a servo driver 132 based on a command from the controller 121.

  The plasticizing moving device 20 is a device that conveys the injection device 11 and presses or separates the heating cylinder 15 (see FIG. 2) of the injection device 11 from the mold device 43 (see FIG. 2). The plasticizing moving device 20 is provided with a plasticizing moving motor 22 for conveying the injection device 11. The plasticizing movement motor 22 is a servo motor and is driven by a servo driver 133 based on a command from the controller 121.

  A mold device 43 (see FIG. 2) filled with an injection material is fixed to the mold clamping device 12. The mold clamping device 12 performs mold opening, mold clamping, and mold closing of the mold device 43. The mold clamping device 12 is provided with a mold clamping motor 57 for operating in this manner. The mold clamping motor 57 is a servo motor and is driven by a servo driver 134 based on a command from the controller 121.

  The ejector device 71 is a device for extruding the solidified molded product from the mold device 43. The ejector device 71 is provided with an eject motor 72 for pushing out a molded product, and a brake mechanism 73 and a brake circuit 74 for braking the eject motor 72. The brake mechanism 73 and the brake circuit 74 constitute a brake device. Details of the brake mechanism 73 and the brake circuit 74 will be described later. The eject motor 72 and the brake circuit 74 are driven by a servo driver 135 based on a command from the controller 121.

  The safety door lock device 99 locks and unlocks the door of the housing of the injection molding machine 1. By releasing the lock of the door, the operator can take out the molded product pushed out from the mold device 43. The safety door lock device 99 is controlled by the controller 121.

  Converter circuit 110 receives electric power from power supply 100 and generates a DC voltage (which may be referred to as “DC power supply”). The inverter circuits 111 to 115 generate an AC voltage for driving the motor from the DC voltage, and output the AC voltage to the measuring motor 83, the injection motor 86, the plasticizing movement motor 22, the mold clamping motor 57, and the ejecting motor 72. To do. Converter circuit 110 may generate a DC voltage that drives other components, such as safety door locking device 99.

  The controller 121 includes a CPU (Central Processing Unit), a working memory, a storage device in which a control program is stored, an input / output port for inputting / outputting various signals, and the like. Each part of the molding machine 1 is controlled.

  The operation unit 122 outputs an operation signal to the controller 121 by an operation by the operator. The operator can input commands such as start and stop of the injection molding process via the operation unit 122.

  Next, the mechanism system of the injection molding machine 1 will be described.

  FIG. 2 is a side view showing a mechanism system of the injection molding machine according to the embodiment of the present invention.

  The injection device 11 and the mold clamping device 12 are arranged to face each other. The injection device 11 is supported by an injection device frame 14, and the injection device frame 14 is supported by a molding machine frame 13. A guide 81 is supported in the longitudinal direction of the injection device frame 14.

  A ball screw shaft 21 is rotatably supported on the injection device frame 14, and one end of the ball screw shaft 21 is connected to a plasticizing movement motor 22. The ball screw shaft 21 and the ball screw nut 23 are screwed together, and the ball screw nut 23 and the injection device 11 are connected via a spring 24 and a bracket 25. Thus, when the plasticizing movement motor 22 is driven in the forward direction or the reverse direction, this rotational motion is converted into a linear motion by the combination of the ball screw shaft 21 and the ball screw nut 23, that is, the screw device 91. Linear motion is transmitted to the bracket 25. Then, the bracket 25 moves in the direction of arrow A along the guide 81, and the injection device 11 advances and retreats. An injection motor 86 is fixedly supported on the bracket 25 via a frame (not shown). In a state where the injection motor 86 is stopped, the bracket moves in the direction of arrow A, so that the injection device includes the heating cylinder 15, the screw 26, the metering motor 83, the injection motor 86, the support member 82, and the like. 11 moves with the bracket 25.

  A heating cylinder 15 is fixed to the bracket 25 toward the front (left side in FIG. 2), and an injection nozzle 16 is provided at the front end of the heating cylinder 15 (left end in FIG. 2). A hopper 17 is disposed in the heating cylinder 15, and a screw 26 is disposed in the heating cylinder 15 so as to be movable back and forth (movable in the left and right direction in FIG. 2) and rotatable. The right end in FIG. 2 is supported by the support member 82.

  A measuring motor 83 is attached to the support member 82, and the rotation of the driving shaft of the measuring motor 83 is transmitted to the screw 26 via the timing belt 84.

  A ball screw shaft 85 is rotatably supported in parallel with the screw 26 on a frame (not shown) to which the injection motor 86 is fixed. The ball screw shaft 85 and the injection motor 86 are connected via a timing belt 87. The front end of the ball screw shaft 85 is screwed with a ball screw nut 89 fixed to the support member 82. Thus, when the injection motor 86 is driven, the rotational motion is converted into a linear motion by the combination of the ball screw shaft 85 and the ball screw nut 89, that is, the screw device 92, and the linear motion is transmitted to the support member 82. Is done.

  Due to the configuration of the injection device 11 as described above, in the metering process, the metering motor 83 is driven, the screw 26 is rotated via the timing belt 84, and the resin supplied from the hopper 17 is contained in the heating cylinder 15. It is heated, melted, and collected in front of the screw 26 as the screw 26 rotates.

  In the injection process, the injection nozzle 16 is pressed against the fixed mold 44, the injection motor 86 is driven, and the ball screw shaft 85 rotates via the timing belt 87. At this time, the support member 82 moves with the rotation of the ball screw shaft 85 and moves the screw 26 forward (moves to the left in FIG. 2). As the screw 26 advances and rotates, the resin stored in front of the screw 26 is injected from the injection nozzle 16 and filled in a cavity space 47 formed between the fixed mold 44 and the movable mold 45.

  The mold clamping device 12 is supported by the molding machine frame 13. A mold apparatus 43 including a fixed mold 44 and a movable mold 45 is fixed to the mold clamping device 12.

  The mold clamping device 12 includes a fixed platen 51, a toggle support 52, a tie bar 53 installed between the fixed platen 51 and the toggle support 52, a movable platen that faces the fixed platen 51 and is movable along the tie bar 53. 54, and a toggle mechanism 56 disposed between the movable platen 54 and the toggle support 52. A fixed mold 44 and a movable mold 45 are respectively attached to the fixed platen 51 and the movable platen 54 so as to face each other.

  The toggle mechanism 56 is swingable relative to the cross head 58, swingable relative to the toggle head 52, toggle lever 62 supported swingably relative to the toggle support 52, and swingable relative to the movable platen 54. A supported toggle arm 63 is provided. The toggle lever 61 and the toggle lever 62 are linked to each other, and the toggle lever 62 and the toggle arm 63 are linked to each other.

  A ball screw shaft 64 is rotatably supported on the toggle support 52. The ball screw shaft 64 is screwed with a ball screw nut 65 fixed to the cross head 58. The mold clamping motor 57 (FIG. 1) is attached to the side surface of the toggle support 52 in order to drive the ball screw shaft 64 to rotate.

  When the mold clamping motor 57 (FIG. 1) is driven, this rotational motion is converted into a linear motion by the combination of the ball screw shaft 64 and the ball screw nut 65, that is, the screw device 93. This linear motion is transmitted to the crosshead 58, and the crosshead 58 advances and retreats in the direction of arrow C. When the cross head 58 moves forward (moves to the right in FIG. 2), the toggle mechanism 56 extends and the movable platen 54 moves forward to perform mold closing and mold clamping. On the other hand, when the cross head 58 moves backward (moves to the left in FIG. 2), the toggle mechanism 56 bends, the movable platen 54 moves backward, and mold opening is performed.

  The ejector device 71 is provided on the back surface of the movable platen 54. The ejector device 71 includes an eject pin that extends through the movable mold 45 and whose front end reaches the cavity space 47. The eject pin is supported so as to be movable in parallel. The rotational motion of the ejecting motor 72 is transmitted through a timing belt and a screw device that is a combination of a ball screw shaft and a ball screw nut to move the eject pin. The eject pin support mechanism is provided with a return spring for returning the eject pin projected into the cavity space to the original position. When the eject pin pushes out the molded product from the mold device 43, the brake mechanism 73 (FIG. 1) brakes the rotation of the eject motor 72 so that the eject pin does not move. The mechanism for displacing these eject pins corresponds to an example of a movable mechanism according to the present invention.

  FIG. 3 is a longitudinal sectional view showing the ejecting motor and the brake mechanism according to the embodiment.

  The eject motor 72 includes a frame 721, a rotor having a core 722 and a permanent magnet 723, a stator having a core 724 and a motor coil 725, an output shaft 70a, and a bearing that rotatably supports the output shaft 70a. 726. The rotor is fixed to the output shaft 70a, and the stator is fixed to the frame 721. The ejecting motor 72 generates a magnetic field in the motor coil 725 by the AC voltage of the servo driver 135, and a rotational torque is generated in the stator by this magnetic field to rotate the output shaft 70a. The ejecting motor 72 is provided with an encoder 729 that detects a rotational position via a spline portion 728.

  The brake mechanism 73 includes a base 731 fixed to the frame 721, a spring 732 as an urging member, an exciting coil 733, an armature 734, a brake hub 735, a friction pad 736, and a housing that accommodates each component. 737. Here, the armature 734 corresponds to an example of a mover according to the present invention. The brake hub 735 corresponds to an example of a braking target according to the present invention. A friction member may be provided on the contact surface between the armature 734 and the brake hub 735.

  The base 731 holds the spring 732 and the exciting coil 733. The base portion 731 is defined in the frame 721 of the ejecting motor 72 with the output shaft 70a being rotatably passed through the center.

  The brake hub 735 has a disk shape, and is splined to the output shaft 70 a of the ejecting motor 72 via a spline portion 728. The brake hub 735 is disposed so as to be sandwiched between the armature 734 and the friction pad 736.

  The armature 734 has a disk shape, is locked so as not to rotate in the rotation direction of the output shaft 70a, and is held so as to be movable in the axial direction of the output shaft 70a. The armature 734 is made of a magnetic material and has a characteristic that is attracted by electromagnetic force. The friction pad 736 is fixed to the housing 737, for example, so as not to move in the rotation direction and the axial direction of the output shaft 70a.

  The spring 732 generates a biasing force that presses the armature 734 against the brake hub 735. When the armature 734 is pressed against the brake hub 735, the brake hub 735 is strongly sandwiched between the armature 734 and the friction pad 736 and the brake is held.

  The exciting coil 733 generates an electromagnetic force using the base 731 as a yoke when a current flows. This electromagnetic force opposes the biasing force of the spring 732 and attracts the armature 734. As a result, the brake hub 735 is separated from the armature 734 and the friction pad 736, and the brake is released.

  FIG. 4 is a circuit diagram illustrating an example of a brake circuit according to the embodiment. Next, the circuit configuration of the brake device will be described.

  The brake circuit 74 is a circuit for driving and stopping the excitation coil 733 of the brake mechanism 73, and is provided in the casing of the eject motor 72, for example. The brake circuit 74 includes a rectification unit 741, a first return unit 742, and a second return unit 743. The configuration in which the first reflux unit 742 and the second reflux unit 743 are combined corresponds to an example of the reflux unit according to the present invention.

  The rectifying unit 741 receives the AC voltage V1 and outputs the rectified voltage to the exciting coil 733 as a driving voltage. In the example of FIG. 4, the rectifying unit 741 is a half-wave rectifying circuit, and includes a rectifying element (for example, a rectifying diode) 744 connected in series with the first switch 136 as a main element. The AC voltage V <b> 1 is a voltage supplied from the inverter circuit 111, for example, and is switched between input and cutoff by the first switch 136. The first switch 136 may be an external element of the brake circuit 74. In the example of FIG. 1, the first switch 136 is provided in the servo driver 134 as an external element, and is connected to the brake circuit 74 via a wiring. The first switch 136 may be composed of a semiconductor switch or a relay.

  The first reflux unit 742 includes a rectifying element (for example, a rectifying diode) 745 that allows a current to flow in one direction, and a second switch 137 connected in series to the rectifying element 745. The first return unit 742 is connected to the excitation coil 733 to form a closed circuit, and can return current to and from the excitation coil 733 when the second switch 137 is closed. The recirculating current flows on a current path in which the rectifying element 745, the second switch 137, and the exciting coil 733 are connected in series. The second switch 137 may be an external element of the brake circuit 74. In the example of FIG. 1, the second switch 137 is provided in the servo driver 134 as an external element, and is connected to the brake circuit 74 via wiring. The second switch 137 may be composed of a semiconductor switch or a relay.

  The second reflux unit 743 includes a rectifier element (for example, a rectifier diode) 746 that allows current to flow in one direction, and a Zener diode 747 connected in series with the rectifier element 746. The second recirculation unit 743 is connected to the excitation coil 733 to form a closed circuit. When a counter electromotive voltage exceeding the Zener voltage is generated in the excitation coil 733, the second reflux unit 743 recirculates current to and from the excitation coil 733. The recirculating current flows on a current path in which the rectifying element 746, the Zener diode 747, and the exciting coil 733 are connected in series. The Zener diode 747 corresponds to an example of a voltage generation unit according to the present invention. When the current flows back to the Zener diode 747, a Zener voltage is generated between both terminals of the Zener diode 747 in a direction opposite to the flowing current and not proportional to the flowing current.

FIG. 5 is a graph comparing the coil voltage (a) and exciting current (b) of the brake circuit of FIG. 4 with the coil voltage (c) and exciting current (d) of the conventional brake circuit. The coil voltage V _n1 in FIG. 5A indicates the voltage at the node 748 in FIG. An excitation current _In2 in FIG. 5B indicates a current flowing through the node 749 in FIG.

  The conventional brake circuit according to FIGS. 5C and 5D has a configuration in which the second reflux unit 743 and the second switch 137 are omitted from the circuit of FIG.

  In the brake circuit 74 of FIG. 4, when the brake is released, the controller 121 closes both the first switch 136 and the second switch 137 (hereinafter, this period is referred to as an “on period”). At this time, as shown in the ON period of FIGS. 5A and 5B, the first switch 136 is closed, so that an AC voltage is input and the voltage rectified by the rectifier 741 is the excitation coil 733. Is output. A drive current is output from the rectifier 741 to the exciting coil 733 in a section where the voltage is large. On the other hand, in the section where the voltage is near zero, the current output of the rectifying unit 741 is zero, but the current flows back between the first return unit 742 and the excitation coil 733 by the back electromotive force of the excitation coil 733. At this time, only a voltage drop that combines the ON resistance of the second switch 137, the wiring resistance, and the forward voltage of the rectifying element 745 occurs at the node 748, so that no current flows through the second reflux unit 743. That is, the path to the exciting coil 733 is switched by the second switch 137 to the second reflux unit 743 including the Zener diode 747 as the voltage generation unit or the first reflux unit 742. That is, the reflux unit including the first reflux unit 742 and the second reflux unit 743 switches the path for the excitation coil 733 from the path not including the voltage generation unit to the path including the voltage generation unit. The path that does not include the voltage generation unit only needs to include a rectifying element and form a closed circuit with the excitation coil 733. Further, the path including the voltage generation unit may include the rectifying element and the voltage generation unit, and a closed circuit may be formed between the excitation coil 733 and the path. By switching between a closed circuit and a state that is not a closed circuit by opening and closing (cutting off or connecting) a switch provided in the reflux unit, switching of the path can be realized. Instead of the rectifying element 745 of the first reflux unit 742 and the rectifying element 746 of the second reflux unit 743, a configuration in which one rectifying element is shared may be employed. Even with such a configuration, the same operation can be obtained.

  Due to such circuit operation, during the ON period, a certain current or more flows through the exciting coil 733, and the armature 734 is attracted by electromagnetic force to be in a brake release state.

  On the other hand, when the brake holding state is set, the controller 121 opens both the first switch 136 and the second switch (hereinafter, this period is referred to as an “off period”). 5A and 5B, when the first switch 136 and the second switch 137 are opened, the current amount of the exciting coil 733 changes and the excitation coil 733 is reversed. An electromotive force is generated. When the counter electromotive force exceeds the Zener voltage, a current flows through the Zener diode 747 of the second return unit 743, and the current flows back between the second return unit 743 and the exciting coil 733. At this time, since a Zener voltage Vz opposite to the counter electromotive force is applied between both terminals of the exciting coil 733, the exciting current of the exciting coil 733 is quickly attenuated.

  By such a circuit operation, at the beginning of the off period, the exciting current of the exciting coil 733 is attenuated, and the electromagnetic force by the exciting coil 733 becomes smaller quickly than the urging force of the spring 732. As a result, the armature 734 is pressed against the brake hub 735 by the urging force of the spring 732, and the brake is held.

  In the conventional brake circuit, as shown in the waveforms of FIGS. 5C and 5D, after the input of the AC voltage is cut off at the beginning of the off period, the excitation current is rapidly increased by the back electromotive force of the excitation coil 733. Attenuation cannot be obtained. As a result, a relatively large delay occurs between the on-period and the brake holding state. Compared to such a brake circuit, it can be seen that the brake circuit 74 of the present embodiment can quickly bring the brake into a holding state.

  In the injection molding machine 1 of the present embodiment, a series of injection molding steps are continuously repeated. In one injection molding process, for example, the mold clamping device 12 closes and molds the mold device 43, the conveying process in which the injection device 11 is conveyed by the plasticizing movement device 20, and the mold from the injection device 11 to the mold. An injection process in which a molding material is injected into the mold apparatus 43, a mold opening process in which the mold clamping apparatus 12 opens the mold apparatus 43, an ejection process in which the ejector apparatus 71 pushes out the molded product, and an extraction process in which the molded product is taken out are included.

  In such an injection molding process, after the ejector device 71 pushes out the molded product from the mold device 43, the first switch 136 and the second switch 137 are closed, and the brake mechanism 73 is released. Then, after the ejector device 71 pushes out the molded product, the controller 121 switches the first switch 136 and the second switch 137 to open almost simultaneously, and the brake mechanism 73 enters the brake holding state.

  The controller 121 unlocks the safety door locking device 99 at the timing when the brake is held. Specifically, a control program is created so that the lock is released at such timing. Alternatively, the controller 121 may be configured to release the lock when the sensor detects that the brake is held. By unlocking the door, the operator can take out the molded product and shift to the next injection molding cycle.

  As described above, according to the brake circuit 74 of the injection molding machine 1 of the present embodiment, the ejector device 71 can be quickly switched from the brake release state to the brake holding state. Therefore, one injection molding cycle can be shortened, and a great time reduction can be achieved when a large number of molded products are continuously manufactured. In addition, when the switching from the brake release state to the brake holding state is slow, the friction member or the friction pad 736 provided on the contact surface between the armature 734 and the brake hub 735 rubs, and these reductions progress quickly. However, according to the brake circuit 74 of the injection molding machine 1 of the present embodiment, such reduction can be reduced.

  In addition, according to the brake circuit 74 of the present embodiment, the Zener diode 747 is used as a configuration for applying a voltage in a direction opposite to the refluxing current when the exciting current of the exciting coil 733 is attenuated. For this reason, the voltage generated when the exciting current is attenuated does not change in proportion to the magnitude of the current, and becomes a substantially constant voltage. Therefore, the excitation current is quickly controlled while the voltage value is easily controlled so that the voltage generated in the excitation coil 733 does not exceed the limit voltage of other circuits or the voltage does not become a noise generation source. It becomes possible to attenuate.

  The brake circuit 74 is not limited to the specific example of FIG. For example, the second reflux unit 743 may be connected between the anode of the rectifying element 745 of the first reflux unit 742 and the ground. In this case, the current recirculated by the second recirculation unit 743 flows through the current path in which the Zener diode 747 and the rectifier elements 745 and 746 are connected in series, and does not flow through the path including the second switch 137. The second reflux unit 743 may have a configuration in which the rectifying element 745 and the rectifying element 746 are shared, and the Zener diode 747 is connected in parallel with the second switch 137. Further, as the brake circuit 74, the following modifications may be employed.

(First modification)
FIG. 6 is a circuit diagram showing a first modification of the brake circuit according to the embodiment.
The brake circuit 74A according to the first modification employs a capacitor 750 instead of the Zener diode 747 as a voltage generation unit that generates a voltage opposite to the current flowing back in the second return unit 743. The other configuration is the same as that of the circuit of FIG. 4, and detailed description of the same configuration is omitted.

  The capacitance value of the capacitor 750 is appropriately selected according to the inductance value of the exciting coil 733 and the exciting current. The capacitance value of the capacitor 750 is selected so that the capacitor 750 generates a voltage that can quickly attenuate the exciting current of the exciting coil 733 when the first and second switches 136 and 137 are switched to the closed state. Furthermore, the capacitance value of the capacitor 750 is selected so that this voltage does not exceed the limit voltage of other circuit units or become a noise source.

  Also in the brake circuit 74A of the first modified example, when the first and second switches 136 and 137 are switched to close, an appropriate voltage is generated between both terminals of the capacitor 750, and the exciting current of the exciting coil 733 is quickly attenuated. can do. Further, according to the brake circuit 74A of the first modified example, in order to attenuate the exciting current, the capacitor 750 is used instead of a resistor that causes a large current to flow proportionally when a large voltage is applied. Therefore, when the exciting current is attenuated, it is easy to control the current and voltage so as not to harm other circuit portions.

  When the capacitor 750 is employed as the voltage generator of the second reflux unit 743, a discharge circuit that leaks the electricity accumulated in the capacitor 750 until the next switching of the brake circuit 74A may be provided. Further, the accumulated electricity may be returned to the converter circuit 110 or the inverter circuit 111.

(Second modification)
FIG. 7 is a circuit diagram showing a second modification of the brake circuit according to the embodiment.
The brake circuit 74B of the second modified example employs a DC power source 751 instead of the Zener diode 747 as a voltage generating unit that generates a voltage opposite to the current flowing back in the second return unit 743. The other configuration is the same as that of the circuit of FIG. 4, and detailed description of the same configuration is omitted.

  The DC power supply 751 may be an output of the converter circuit 110, for example. The direct current power source 751 is connected so that a voltage is applied in the direction opposite to the current flowing back in the second reflux unit 743.

  Also in the brake circuit 74B of the second modified example, when the first and second switches 136, 137 are switched to close, the voltage of the DC power source 751 is generated between both terminals of the capacitor 750, and the exciting current of the exciting coil 733 is quickly changed. Can be attenuated. Further, according to the brake circuit 74B of the second modified example, the voltage applied to attenuate the exciting current does not change in proportion to the magnitude of the current, and becomes a substantially constant voltage. Therefore, the excitation current is quickly controlled while the voltage value is easily controlled so that the voltage generated in the excitation coil 733 does not exceed the limit voltage of other circuits or the voltage does not become a noise generation source. Can be attenuated

  Furthermore, according to the brake circuit 74B of the second modified example, when the excitation current is attenuated, the energy of the excitation coil 733 is returned to the converter circuit 110 or the inverter circuit 111 via the DC power source 751 and used as circuit power. It becomes possible.

(Modification 1 of injection molding machine)
Here, a modification of the injection molding machine will be described. The injection molding machine of Modification 1 is a vertical type, and the plasticizing moving device moves up and down the injection device and presses or separates the mold and the heating cylinder. Furthermore, the brake device is incorporated in the plasticizing movement device. In the first modification, the mechanism for moving the injection molding machine corresponds to an example of the movable mechanism according to the present invention.

In such an injection molding machine, the controller controls the injection device to move to the upper standby position and stop before the end of the injection molding process or the interruption of the process. Specifically, the controller drives the plasticizing moving device to move the injection device to the upper standby position, and then cuts off the power input to the plasticizing moving motor and the brake device to switch to the brake holding state. At this time, in the conventional brake device, due to the delay from the disconnection of the power input to the brake device to the switch to the brake holding state, the injection device is slightly lowered from the standby position by its own weight, and then stops. On the other hand, according to the injection molding machine of the first modified example, since the brake device according to the present invention is employed, there is no such lowering of the injection device, and the injection device immediately stops at the standby position.

  Further, the movement to the standby position and the stop may be performed manually by the operator. In this case, the brake device according to the present invention is employed, so that the injection is quickly performed by the stop operation. The apparatus can be stopped and operability can be improved.

(Modification 2 of injection molding machine)
In the injection molding machine according to the modified example 2, before the injection device injects the molding material, a brake device is mounted on the plasticizing movement motor in order to hold the injection nozzle at a position in pressure contact with the mold device. In Modification 2, the mechanism for moving the injection molding machine corresponds to an example of a movable mechanism according to the present invention.

  If the injection nozzle is kept in pressure contact with the mold apparatus, heat escapes from the injection nozzle to the mold apparatus, which may affect the melting of the molding material in the heating cylinder. In order to avoid this, for each injection of the molding material, the injection nozzle is separated from the mold apparatus, and the injection nozzle is pressed against the mold apparatus again at the next injection. In the injection molding machine according to the modified example 2, when the injection nozzle is pressed against the mold device in this way, the injection nozzle is stopped by braking the plasticizing movement motor by the brake device according to the present invention. By using the brake device in this way, it is possible to improve the accuracy of the holding position of the injection nozzle and improve the accuracy of the pressure contact force of the injection nozzle. Further, such a braking step is performed for each molding material injection process. For this reason, the quick switching from the brake release state to the brake holding state can shorten one injection molding cycle, greatly reducing the time required when manufacturing many molded products continuously. Can be planned.

  The embodiment of the present invention has been described above. The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the brake device according to the present invention has been described as a configuration for braking the ejector motor of the ejector device and a configuration for braking the plasticizing movement device. However, the brake device may be applied to a configuration that brakes other parts. Moreover, you may comprise a brake device as a module different from a motor, without making it the form integrated with the motor.

  Moreover, in the said embodiment, the example which applied the Zener diode 747, the capacitor | condenser 750, or DC power supply 751 was shown as a voltage generation part which concerns on this invention. However, the voltage generator according to the present invention only needs to generate a voltage in the direction opposite to the current flowing back to the exciting coil, and may be, for example, a resistor. In addition, the voltage generator may generate a voltage that is not proportional to the magnitude of the circulating current, and may be, for example, a varistor.

  Further, in the embodiment, the example has been described in which the mover is separated from the braking target by the electromagnetic force of the excitation coil and the brake is released, but conversely, the mover contacts the braking target by the electromagnetic force of the excitation coil. Thus, the brake may be held. Furthermore, the brake device and the brake circuit according to the present invention are not limited to the injection molding machine, and may be mounted on various industrial machines. Further, the urging member of the brake mechanism is not limited to the spring, and any member may be used as long as it generates a repulsive force when contracted. In addition, the details shown in the embodiments can be changed as appropriate without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Injection molding machine 11 Injection apparatus 12 Mold clamping apparatus 20 Plasticization moving apparatus 71 Ejector apparatus 72 Ejector motor 73 Brake mechanism 74 Brake circuit 99 Safety door lock apparatus 110 Converter circuit 111 Inverter circuit 121 Controller 134 Servo driver 136 First switch 137 Second switch 732 Spring (biasing member)
733 Excitation coil 734 Armature (mover)
735 Brake hub (braking target)
741 Rectifier 742 First reflux unit 743 Second reflux unit 744 to 746 Rectifier element 747 Zener diode 750 Capacitor 751 DC power supply

Claims (11)

A movable mechanism driven in part of the injection molding process;
A motor for driving the movable mechanism;
A mover that contacts the braking object and brakes the movable mechanism;
A biasing member that generates a biasing force for moving the mover;
An exciting coil that generates electromagnetic force and moves the mover in a direction that opposes the biasing force;
A first switch for switching between AC voltage input and cutoff;
A rectifier that rectifies the input AC voltage and supplies a drive voltage to the excitation coil;
A reflux unit having a rectifying element, a voltage generation unit, and a second switch, and capable of returning a current to and from the excitation coil;
With
When releasing the electromagnetic force of the exciting coil, the first switch cuts off the input of the AC voltage, and the second switch passes the path of the return part from the path not including the voltage generator. An injection molding machine that changes to a path that includes the generator.   The injection molding machine according to claim 1, wherein the voltage generator generates a voltage opposite to a voltage generated in the exciting coil by a counter electromotive force.   2. The injection molding machine according to claim 1, wherein the voltage generator generates a voltage that is in a direction opposite to a current flowing back to and from the exciting coil and is not proportional to the magnitude of the current flowing back.   The injection molding machine according to claim 3, wherein the voltage generator is a Zener diode.   The injection molding machine according to claim 3, wherein the voltage generator is a capacitor.   The injection molding machine according to claim 3, wherein the voltage generator is a direct current power source. An inverter circuit for generating the AC voltage;
The injection molding machine according to claim 6, wherein the DC power supply is common to a DC power supply supplied to the inverter circuit.   The injection molding machine according to claim 2, wherein the voltage generator is a resistor. The reflux part is
First rectifier having a rectifying element and a second switch connected in series with the rectifying element and capable of returning a current to and from the exciting coil through a path including the rectifying element and the second switch And
A second return part having the voltage generation part and capable of returning current to and from the excitation coil via a path not including the second switch;
The injection molding machine as described in any one of Claims 1-8 provided. A mover that moves and contacts the object to be braked;
A biasing member that generates a biasing force for moving the mover;
An exciting coil that generates electromagnetic force and moves the mover in a direction that opposes the biasing force;
A rectifying unit that rectifies an alternating voltage and supplies a driving voltage to the exciting coil;
A reflux unit having a rectifying element and a voltage generator, and capable of returning a current to and from the excitation coil;
With
When releasing the electromagnetic force of the exciting coil, a brake in which the input of the AC voltage is interrupted and the path of the return part is changed from a path not including the voltage generator to a path including the voltage generator apparatus. This is a brake circuit that drives a brake mechanism that holds or releases braking by moving a mover applied with an urging force by an urging member in a direction opposite to the urging force by an electromagnetic force generated by an exciting coil. And
A rectifying unit that rectifies an alternating voltage and supplies a driving voltage to the exciting coil;
A reflux unit having a rectifying element and a voltage generator, and capable of returning a current to and from the excitation coil;
With
When releasing the electromagnetic force of the exciting coil, a brake in which the input of the AC voltage is interrupted and the path of the return part is changed from a path not including the voltage generator to a path including the voltage generator circuit.

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