JP5774420B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine.

  The injection molding machine molds a molded product by injecting molten resin from an injection apparatus, filling the cavity of a mold apparatus, and solidifying. The mold apparatus includes a fixed mold and a movable mold. Mold closing, mold clamping, and mold opening of the mold apparatus are performed by a mold clamping apparatus.

  As a mold clamping device, a system using a drive source such as a motor and a toggle mechanism is widely used. However, due to the characteristics of the toggle mechanism, it is difficult to change the mold clamping force, and responsiveness and stability. Is bad. In addition, a bending moment may be generated during the operation of the toggle mechanism, and the mounting surface to which the mold apparatus is attached may be distorted.

  Therefore, a mold clamping device has been proposed that uses a linear motor for the mold opening / closing operation and uses the attractive force of an electromagnet for the mold clamping operation (see, for example, Patent Document 1). In the mold clamping device, current supply to the coil of the electromagnet is performed under the control of the control device.

WO05 / 090052 pamphlet

  The mold apparatus is replaced according to the type of the molded product. When a new mold apparatus is mounted, the mold apparatus is temporarily fixed to the mounting surface with bolts, then the mold is closed, and the bolts are tightened and tightened in a clamped state. Instead of the bolt, a clamp device using hydraulic pressure or magnetic force may be used.

  Since this fastening operation is performed by opening the door installed on the cover of the injection molding machine, the current supply to the mold clamping device is stopped when the door is open in order to eliminate the malfunction caused by the control device. .

  In this state, the method using the toggle mechanism can retain the mold clamping force generated in advance, but the method using the electromagnet cannot retain the mold clamping force. This is because the current supply to the coil of the electromagnet by the control device is interrupted. For this reason, in the method using an electromagnet, the main fastening operation is difficult.

  The present invention has been made in view of the above-described problems, and provides an injection molding machine capable of mounting a mold apparatus in a state where current supply to a coil of an electromagnet under control by a control apparatus is stopped. Objective.

In order to solve the above object, an injection molding machine according to an aspect of the present invention is provided.
A first fixing member to which a fixed mold is attached;
A first movable member to which a movable mold is attached;
A second movable member that moves with the first movable member;
A second fixed member disposed between the first movable member and the second movable member;
A mold clamping force generating mechanism that generates a mold clamping force by an attractive force of an electromagnet between the second fixed member and the second movable member;
The mold clamping force generation mechanism includes a current supply unit that supplies current to the coil of the electromagnet, and a control device that controls the current supply unit,
An electric circuit is provided for supplying current to the coil in a state where supply of current to the coil by the current supply unit under control by the control device is stopped.

  ADVANTAGE OF THE INVENTION According to this invention, the injection molding machine which enables attachment of a metal mold | die apparatus in the state which stopped the electric current supply to the coil of the electromagnet under control by a control apparatus is provided.

The figure which shows the state at the time of mold closing of the injection molding machine by one Embodiment of this invention The figure which shows the state at the time of the mold opening of the injection molding machine by one Embodiment of this invention The figure which shows the circuit which supplies an electric current to the coil of the electromagnet of the injection molding machine by one Embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each of the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof will be omitted. Further, a description will be given assuming that the moving direction of the movable platen when performing mold closing is the front and the moving direction of the movable platen when performing mold opening is the rear.

  FIG. 1 is a view showing a state when a mold is closed in an injection molding machine according to an embodiment of the present invention. FIG. 2 is a view showing a state when the mold of the injection molding machine according to the embodiment of the present invention is opened. FIG. 3 is a diagram showing a circuit for supplying a current to an electromagnet coil of an injection molding machine according to an embodiment of the present invention.

  In the figure, 10 is a mold clamping device, Fr is a frame of an injection molding machine, Gd is a guide composed of two rails laid on the frame Fr, and 11 is a fixed platen (first fixing member). The fixed platen 11 may be provided on a position adjustment base Ba that is movable along a guide Gd that extends in the mold opening / closing direction (left-right direction in the drawing). The fixed platen 11 may be placed on the frame Fr.

  A movable platen (first movable member) 12 is disposed facing the fixed platen 11. The movable platen 12 is fixed on the movable base Bb, and the movable base Bb can run on the guide Gd. Thereby, the movable platen 12 is movable in the mold opening / closing direction with respect to the fixed platen 11.

  A rear platen (second fixing member) 13 is disposed at a predetermined distance from the fixed platen 11 and parallel to the fixed platen 11. The rear platen 13 is fixed to the frame Fr via the leg portion 13a.

  Between the fixed platen 11 and the rear platen 13, four tie bars 14 (only two of the four tie bars 14 are shown in the figure) are installed as connecting members. The fixed platen 11 is fixed to the rear platen 13 via the tie bar 14. A movable platen 12 is disposed along the tie bar 14 so as to freely advance and retract. A guide hole (not shown) for penetrating the tie bar 14 is formed at a position corresponding to the tie bar 14 in the movable platen 12. In addition, you may make it form a notch instead of a guide hole.

  A screw portion (not shown) is formed at the front end portion (right end portion in the drawing) of the tie bar 14, and the front end portion of the tie bar 14 is fixed to the fixed platen 11 by screwing and tightening a nut n1 to the screw portion. The rear end of the tie bar 14 is fixed to the rear platen 13.

  A fixed mold 15 is attached to the fixed platen 11, and a movable mold 16 is attached to the movable platen 12. The fixed mold 15 and the movable mold 16 are brought into contact with and separated from each other as the movable platen 12 advances and retreats. Closing, mold clamping and mold opening are performed. As the mold clamping is performed, a cavity space (not shown) is formed between the fixed mold 15 and the movable mold 16, and a molten resin (not shown) injected from the injection nozzle 18 of the injection device 17 is formed in the cavity. The space is filled. A mold apparatus 19 is configured by the fixed mold 15 and the movable mold 16.

  The suction plate 22 (second movable member) is disposed in parallel with the movable platen 12. The suction plate 22 is fixed to the slide base Sb via the mounting plate 27, and the slide base Sb can travel on the guide Gd. As a result, the suction plate 22 can move back and forth behind the rear platen 13. The suction plate 22 may be formed of a magnetic material. The attachment plate 27 may not be provided. In this case, the suction plate 22 is directly fixed to the slide base Sb.

  The rod 39 is connected to the suction plate 22 at the rear end portion and is connected to the movable platen 12 at the front end portion. Therefore, the rod 39 is moved forward as the suction plate 22 moves forward when the mold is closed to move the movable platen 12 forward, and is retracted and moved backward as the suction plate 22 moves back when the mold is opened. Retreat. For this purpose, a hole 41 is formed in the central portion of the rear platen 13 for allowing the rod 39 to pass therethrough.

  The linear motor 28 is a mold opening / closing drive unit for moving the movable platen 12 forward and backward, and is disposed, for example, between the suction plate 22 connected to the movable platen 12 and the frame Fr. The linear motor 28 may be disposed between the movable platen 12 and the frame Fr.

  The linear motor 28 includes a stator 29 and a mover 31. The stator 29 is formed on the frame Fr in parallel with the guide Gd and corresponding to the movement range of the slide base Sb. The mover 31 is formed at a lower end of the slide base Sb so as to face the stator 29 and over a predetermined range.

  The mover 31 includes a core 34 and a coil 35. The core 34 includes a plurality of magnetic pole teeth 33 that are protruded toward the stator 29 and formed at a predetermined pitch, and the coil 35 is wound around each magnetic pole tooth 33. The magnetic pole teeth 33 are formed in parallel to each other in a direction perpendicular to the moving direction of the movable platen 12. The stator 29 includes a core (not shown) and a permanent magnet (not shown) formed to extend on the core. The permanent magnet is formed by alternately magnetizing the N and S poles. A position sensor 75 that detects the position of the mover 31 is disposed.

  When the linear motor 28 is driven by supplying a predetermined current to the coil 35, the mover 31 is moved back and forth. Along with this, the suction plate 22 and the movable platen 12 are advanced and retracted, and the mold can be closed and opened. The linear motor 28 is feedback-controlled based on the detection result of the position sensor 75 so that the position of the mover 31 becomes a set value.

  In the present embodiment, the permanent magnet is disposed on the stator 29 and the coil 35 is disposed on the mover 31, but the coil is disposed on the stator and the permanent magnet is disposed on the mover. You can also. In this case, since the coil does not move as the linear motor 28 is driven, wiring for supplying power to the coil can be easily performed.

  As the mold opening / closing drive unit, a rotary motor and a ball screw mechanism that converts the rotary motion of the rotary motor into a linear motion may be used instead of the linear motor 28.

  The electromagnet unit 37 generates a mold clamping force between the rear platen 13 and the suction plate 22 by the suction force of the electromagnet. This adsorption force is transmitted to the movable platen 12 via the rod 39.

  The mold clamping device 10 is configured by the fixed platen 11, the movable platen 12, the rear platen 13, the suction plate 22, the linear motor 28, the electromagnet unit 37, the rod 39, and the like. The electromagnet unit 37 and the like constitute a mold clamping force generation mechanism. The mold clamping force generation mechanism includes a current supply unit 100 (see FIG. 3) that supplies a current to the coil 48 of the electromagnet 49 and a control device 60 that controls the current supply unit 100.

  The electromagnet unit 37 includes an electromagnet 49 formed on the rear platen 13 side and a suction portion 51 formed on the suction plate 22 side. The suction portion 51 is formed in a predetermined portion of the front end surface of the suction plate 22, for example, a portion that surrounds the rod 39 in the suction plate 22 and faces the electromagnet 49. Further, a groove 45 is formed around a predetermined portion of the rear end surface of the rear platen 13, for example, the rod 39, a core 46 is formed inside the groove 45, and a yoke 47 is formed outside the groove 45. A coil 48 is wound around the core 46 in the groove 45.

  In this embodiment, the electromagnet 49 is formed separately from the rear platen 13 and the attracting portion 51 is formed separately from the attracting plate 22, but the electromagnet is part of the rear platen 13 and the attracting portion is part of the attracting plate 22. May be formed. Moreover, the arrangement of the electromagnet and the attracting part may be reversed. For example, the electromagnet 49 may be provided on the suction plate 22 side, and the suction portion 51 may be provided on the rear platen 13 side.

  When an electric current is supplied to the coil 48 in the electromagnet unit 37, the electromagnet 49 is driven to attract the attracting part 51 and generate a mold clamping force.

  Driving of the linear motor 28 and the electromagnet 49 of the mold clamping device 10 is controlled by the control device 60. The control device 60 includes a CPU, a memory, and the like, and supplies current to the coil 35 of the linear motor 28 and the coil 48 of the electromagnet 49 according to the result calculated by the CPU. A load detector 55 is connected to the control device 60. The load detector 55 is installed at a predetermined position (a predetermined position between the fixed platen 11 and the rear platen 13) of at least one tie bar 14 in the mold clamping device 10, and detects a load applied to the tie bar 14. . The load detector 55 is configured by a sensor that detects the amount of extension of the tie bar 14, for example. The load detected by the load detector 55 is sent to the control device 60.

  As shown in FIG. 3, the control device 60 is connected to a current supply unit (driver) 100 that supplies current to the coil 48 of the electromagnet 49, and controls the current supply unit 100. Control of the current supply unit 100 is performed by a mold clamping processing unit 62 described later.

  The current supply unit 100 is connected to a DC power source (for example, a charger) PW and supplies a current having a current value corresponding to a control signal from the control device 60 to the coil 48 of the electromagnet 49. The current supply unit 100 includes, for example, a power module.

  The current supply unit 100 may include an open / close monitoring switch (not shown) that is turned on to allow current supply to the coil 48 of the electromagnet 49 only when the door installed on the cover of the injection molding machine is closed. When the open / close monitoring switch is turned off, the current supply to the coil 48 of the electromagnet 49 by the current supply unit 100 is cut off.

  Note that the open / close monitoring switch is not included in the current supply unit 100 and may be connected to the control device 60. In this case, when the state of the open / close monitoring switch is turned off, the control device 60 blocks the current supply from the current supply unit 100 to the coil 48 of the electromagnet 49.

Next, the operation of the mold clamping device 10 will be described.

  The mold closing process is controlled by the mold opening / closing processor 61 of the control device 60. In the state of FIG. 2 (the state of mold opening), the mold opening / closing processor 61 supplies current to the coil 35 to drive the linear motor 28. The movable platen 12 moves forward, and the movable mold 16 is brought into contact with the fixed mold 15 as shown in FIG. At this time, a gap δ is formed between the rear platen 13 and the suction plate 22, that is, between the electromagnet 49 and the suction portion 51. Note that the force required for mold closing is sufficiently reduced compared to the mold clamping force.

  Subsequently, the mold clamping processing unit 62 of the control device 60 controls the mold clamping process. The mold clamping processing unit 62 supplies current to the coil 48 of the electromagnet 49 and attracts the attracting unit 51 to the electromagnet 49. Along with this, the clamping force is transmitted to the movable platen 12 via the suction plate 22 and the rod 39, and clamping is performed.

  The mold clamping force is detected by the load detector 55. The detected mold clamping force is sent to the control device 60, and the mold clamping processing unit 62 controls the current supply unit 100 to adjust the current supplied to the coil 48 so that the mold clamping force becomes a set value. Feedback control. During this time, the molten resin melted in the injection device 17 is injected from the injection nozzle 18 and filled into the cavity space of the mold device 19.

  When the resin in the cavity space is cooled and solidified, the mold opening / closing processor 61 controls the mold opening process. The mold clamping processing unit 62 stops supplying current to the coil 48 of the electromagnet 49 in the state of FIG. Accordingly, the linear motor 28 is driven, the movable platen 12 is moved backward, and the movable mold 16 is moved backward as shown in FIG. 2 to open the mold.

Next, mold thickness adjustment at the time of replacement of the mold apparatus 19 will be described.
When a new mold apparatus 19 is attached along with the replacement of the mold apparatus 19, the thickness of the mold apparatus 19 changes, and a gap formed between the rear platen 13 and the suction plate 22 when the mold closing is completed. δ changes.

  Therefore, the injection molding machine includes a mold thickness adjusting device 70 that adjusts the gap δ according to the thickness of the mold device 19. The mold thickness adjusting device 70 includes a mold thickness adjusting motor 71, a gear 72, a nut 73, a rod 39, and the like. The rod 39 passes through the central portion of the suction plate 22, and a screw 43 is formed at the rear end portion of the rod 39. The screw 43 and a nut 73 that is rotatably supported by the suction plate 22 are screwed together. A large-diameter gear (not shown) is formed on the outer peripheral surface of the nut 73, and this gear and a small-diameter gear 72 attached to the output shaft 71a of the mold thickness adjusting motor 71 are engaged with each other. The nut 73 and the screw 43 constitute a movement direction conversion unit, and the rotation direction of the nut 73 is converted into a straight movement of the rod 39 in the movement direction conversion unit.

  When the mold thickness adjusting motor 71 is driven in accordance with the thickness of the mold apparatus 19 and the nut 73 is rotated by a predetermined amount with respect to the screw 43, the position of the rod 39 with respect to the suction plate 22 is adjusted, and the fixed platen 11 and the position of the suction plate 22 with respect to the movable platen 12 are adjusted, and the gap δ can be set to an optimum value. That is, the mold thickness is adjusted by changing the distance between the movable platen 12 and the suction plate 22 in the mold opening / closing direction (left and right direction in the figure).

  The mold thickness adjusting motor 71 may be a servo motor and may include an encoder unit 71b. The encoder unit 71 b detects the amount of rotation of the output shaft 71 a of the mold thickness adjusting motor 71 and transmits the detection result to the control device 60. The control device 60 performs feedback control of the mold thickness adjusting motor 71 so that the gap δ becomes a set value.

Next, attachment of the mold apparatus 19 will be described.
When a new mold apparatus 19 is attached, the mold apparatus 19 is temporarily fixed to the fixed platen 11 with bolts while being suspended by a crane or the like. Thereafter, the movable platen 12 moves forward and contacts the mold device 19, and then the mold device 19 is clamped. In the clamped state, the fixed mold 15 is fixed to the fixed platen 11 and the movable mold 16 is fixed to the movable platen 12 with bolts. Instead of the bolt, a clamp device using hydraulic pressure or magnetic force may be used.

  Since the main fastening operation is performed by opening the door installed on the cover of the injection molding machine, the current supply to the coil 48 of the electromagnet 49 by the current supply unit 100 is stopped (hereinafter also referred to as “stop state”). Done in This is to eliminate malfunctions caused by the control device 60.

  In the stop state, drive control of a drive source (including the electromagnet 49, the linear motor 28, and the mold thickness adjusting motor 71) whose operation is feedback-controlled based on detection results of various detectors is automatically stopped. The servo may be off.

  The injection molding machine of the present embodiment includes an electric circuit 200 that supplies a current to the coil 48 of the electromagnet 49 in a stopped state.

  As shown in FIG. 3, the electric circuit 200 connects a coil 48 of the electromagnet 49 and a DC power source (for example, a charger) PW, and supplies current to the electromagnet 49 independently of the current supply unit 100. Unlike the current supply unit 100, the electric circuit 200 is not connected to the control device 60 and is not controlled by the control device 60.

  When the electric circuit 200 supplies a current to the coil 48 of the electromagnet 49, the electromagnet 49 attracts the attracting part 51. Along with this, the clamping force is transmitted to the movable platen 12 via the suction plate 22 and the rod 39, and clamping is performed. Therefore, the mold clamping force can be generated in the stopped state, and the mold can be fixed permanently.

  The electric circuit 200 includes, for example, a manual switch 202, a gap monitoring switch 204, and a variable resistor 206. When both the manual switch 202 and the gap monitoring switch 204 are in an on state in which current supply to the coil 48 is allowed, a current having a current value corresponding to the resistance value of the variable resistor 206 is supplied to the coil 48 of the electromagnet 49. 49 adsorbs the adsorbing part 51.

  The manual switch 202 is a switch that can be manually switched between an on state in which current supply to the coil 48 of the electromagnet 49 is allowed and an off state in which the current is prohibited. The current supply by the electric circuit 200 can be started and ended at the user's will.

  The gap monitoring switch 204 is turned on to allow current supply only when the gap δ formed between the electromagnet 49 and the attracting portion 51 is equal to or less than the predetermined value δ0, and supplies current when the gap δ exceeds the predetermined value δ0. It becomes the off state which prohibits. Since current supply by the electric circuit 200 is allowed only when the gap δ is equal to or less than the predetermined value δ0, when the electromagnet 49 attracts the attracting portion 51, the attracting plate 22, the movable platen 12, the movable mold 16 and the like are advanced. Can be limited. The predetermined value δ0 is set, for example, within a range of 1.0 mm to 1.5 mm.

  The gap monitoring switch 204 may be an operation switch that is installed on the rear platen 13 side and operated by an operation piece installed on the suction plate 22 side. The gap monitoring switch 204 may be an electromagnetic contactor that can be switched between an on state and an off state in accordance with the operation of the operation switch.

  The operation switch and the operation piece may be disposed in reverse, the operation switch may be disposed on the suction plate 22 side, and the operation piece may be disposed on the rear platen 13 side. Further, a non-contact type proximity switch may be used instead of the operation switch.

  The variable resistor 206 makes the current value of the current supplied to the coil 48 of the electromagnet 49 variable, and the resistance value is changed manually. As the resistance value decreases, the current value increases and the attractive force of the electromagnet 49 increases. Therefore, it is possible to adjust the clamping force using the variable resistor 206.

  Next, a method of attaching the mold device 19 (main fastening operation) using the injection molding machine having the above configuration will be described.

First, after the temporary fixing operation, the linear motor 28 is driven to bring the movable platen 12 into contact with the movable mold 16. At this time, the gap δ (> 0) formed between the electromagnet 49 and the attracting portion 51 is equal to or less than the predetermined value δ0, and the gap monitoring switch 204 is turned on. The distance between the suction plate 22 and the movable platen 12 may be adjusted using the mold thickness adjusting device 70 after the linear motor 28 is driven or before the linear motor 28 is driven so that the gap δ is equal to or less than the predetermined value δ0.

  Next, when the door of the injection molding machine is opened, the injection molding machine is stopped, and the current supply to the coil 48 of the electromagnet 49 by the current supply unit 100 is interrupted.

  Next, a current is supplied to the coil 48 of the electromagnet 49 by the electric circuit 200. First, the manual switch 202 is turned on, then the resistance value of the variable resistor 206 is gradually lowered, and the current value flowing through the coil 48 is gradually raised to a set value. Therefore, the electromagnet 49 attracts the attracting part 51, and the clamping force is transmitted to the movable platen 12 through the attracting plate 22 and the rod 39, and the clamping is performed. Therefore, the main fastening operation can be performed in the mold clamping state.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications and substitutions can be made to the above embodiment without departing from the scope of the present invention. Can be added.

  For example, the electric circuit 200 of the above embodiment has a switch that allows current supply to the coil 48 of the electromagnet 49 when the injection molding machine is in a stopped state and prohibits current supply to the coil 48 when the stopped state is released. May include. It is possible to prevent both the electric circuit 200 and the current supply unit 100 from supplying current to the coil 48 of the electromagnet 49 at the same time.

10 mold clamping device 11 fixed platen (first fixing member)
12 Movable platen (first movable member)
13 Rear platen (second fixing member)
15 Fixed mold 16 Movable mold 22 Suction plate (second movable member)
37 Electromagnet Unit (Clamping Force Generation Mechanism)
48 Coil 49 Electromagnet 60 Controller 100 Current supply unit 200 Electric circuit 204 Gap monitoring switch 206 Variable resistance

Claims (3)

A first fixing member to which a fixed mold is attached;
A first movable member to which a movable mold is attached;
A second movable member that moves with the first movable member;
A second fixed member disposed between the first movable member and the second movable member;
A mold clamping force generating mechanism that generates a mold clamping force by an attractive force of an electromagnet between the second fixed member and the second movable member;
The mold clamping force generation mechanism includes a current supply unit that supplies current to the coil of the electromagnet, and a control device that controls the current supply unit,
An injection molding machine comprising: an electric circuit that supplies current to the coil in a state where supply of current to the coil by the current supply unit under control by the control device is stopped.   The injection molding machine according to claim 1, wherein the electric circuit includes a variable resistor that makes a current value of a current supplied to the coil variable.   The electrical circuit allows current supply to the coil when a gap formed between the electromagnet and an attracting portion attracted by the electromagnet is equal to or less than a predetermined value, and when the gap exceeds a predetermined value The injection molding machine according to claim 1, further comprising a switch that prohibits current supply to the coil.

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