JP5722153B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine including an electromagnet that drives a mold clamping operation.

  2. Description of the Related Art Conventionally, in an injection molding machine, resin is injected from an injection nozzle of an injection device, filled into a cavity space between a fixed mold and a movable mold, and solidified to obtain a molded product. ing. A mold clamping device is provided to move the movable mold relative to the fixed mold to perform mold closing, mold clamping, and mold opening.

  The mold clamping device includes a hydraulic mold clamping device that is driven by supplying oil to a hydraulic cylinder, and an electric mold clamping device that is driven by an electric motor. It is widely used because it has high controllability, does not pollute the surroundings, and has high energy efficiency. In this case, by driving the electric motor, the ball screw is rotated to generate a thrust, and the thrust is expanded by a toggle mechanism to generate a large mold clamping force.

  However, since the electric type mold clamping device having the configuration uses a toggle mechanism, it is difficult to change the mold clamping force due to the characteristics of the toggle mechanism, and the responsiveness and stability are improved. Unfortunately, the clamping force cannot be controlled during molding. Therefore, a mold clamping device is provided in which the thrust generated by the ball screw can be directly used as a mold clamping force. In this case, since the torque of the electric motor and the mold clamping force are proportional, the mold clamping force can be controlled during molding.

  However, in the conventional mold clamping device, the load resistance of the ball screw is low, and not only a large mold clamping force cannot be generated, but also the mold clamping force fluctuates due to torque ripple generated in the electric motor. In addition, in order to generate the mold clamping force, it is necessary to constantly supply current to the motor, and the power consumption and heat generation amount of the motor increase. Therefore, it is necessary to increase the rated output of the motor by that amount. The cost of the device becomes high.

  Therefore, a mold clamping device using a linear motor for the mold opening / closing operation and utilizing the attractive force of an electromagnet for the mold clamping operation is conceivable (for example, Patent Document 1).

WO05 / 090052 pamphlet

  However, when using a mold clamping device that utilizes the attractive force of an electromagnet as described in Patent Document 1, there is a problem that the coil becomes hot due to the driving of the electromagnet and the coil may be burned out.

  Then, this invention aims at provision of the injection molding machine which can cool a coil efficiently, maintaining required mold clamping force.

In order to achieve the above object, according to one aspect of the present invention, a first fixing member to which a fixed mold is attached;
A second fixing member disposed opposite to the first fixing member;
A first movable member to which a movable mold is attached;
A second movable member connected to the first movable member and moving together with the first movable member,
A mold clamping force generating mechanism for generating a mold clamping force with the second fixed member and the second movable member;
An electromagnet is formed on the second fixed member or the second movable member constituting the mold clamping force generating mechanism, and the inside of the second fixed member or the second movable member on which the electromagnet is formed. A fluid passage through which a cooling fluid passes ,
The second fixed member or the second movable member in which the fluid passage is formed is formed of an electromagnetic laminated steel plate, and the fluid passage is formed to extend in the laminating direction of the electromagnetic laminated steel plate . An injection molding machine is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the injection molding machine which can cool a coil efficiently can be obtained, maintaining required clamping force.

It is a figure which shows the state at the time of the mold closing of the mold clamping apparatus in the injection molding machine of embodiment of this invention. It is a figure which shows the state at the time of the mold opening of the mold clamping apparatus in the injection molding machine of embodiment of this invention. FIG. 3 (A) is a plan view of the rear platen 13 viewed from the suction plate 22 side in the mold clamping direction, and FIG. 3 (B) is a plan view of the rear platen 13 including the cooling water channel 70 according to one embodiment. 2 is a cross-sectional view of a main part of a rear platen 13. FIG. 3 is a cross-sectional view schematically showing a magnetic circuit formed on the rear platen 13 and the suction plate 22. FIG. The single-piece figure of the rear platen 13 provided with the cooling water channel 71 by another one Example is shown, FIG. 5 (A) is the top view which looked at the rear platen 13 from the adsorption | suction board 22 side in the mold clamping direction, FIG. FIG. 3 is a cross-sectional view of a main part of a rear platen 13. It is a figure which shows an example of the combination aspect of the cooling water channel 70 and the cooling water channel 71, and is sectional drawing of the rear platen 13 and the adsorption | suction board 22. FIG.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In the present embodiment, for the mold clamping device, the moving direction of the movable platen when closing the mold is the front, the moving direction of the movable platen when opening the mold is the rear, and the injection device is the injection The description will be made assuming that the moving direction of the screw when performing the measurement is the front and the moving direction of the screw when performing the measurement is the rear.

  FIG. 1 is a diagram showing a state when a mold clamping device is closed in an injection molding machine according to an embodiment of the present invention, and FIG. 2 is a state when the mold clamping device is opened in the injection molding machine according to the embodiment of the present invention. FIG. In FIGS. 1 and 2, the hatched members show the main cross section.

  In the figure, 10 is a mold clamping device, Fr is a frame (frame) of an injection molding machine, Gd is a guide movable with respect to the frame Fr, 11 is a guide not shown or fixed on the frame Fr. A rear platen 13 is disposed at a predetermined distance from the fixed platen 11 and opposed to the fixed platen 11, and four tie bars 14 (in the figure) are disposed between the fixed platen 11 and the rear platen 13. Shows only two of the four tie bars 14). The rear platen 13 is fixed with respect to the frame Fr.

  A movable platen 12 is disposed along the tie bar 14 so as to face the fixed platen 11 so as to be movable back and forth in the mold opening / closing direction. For this purpose, the movable platen 12 is fixed to the guide Gd, and 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. A suction plate 22 described later is also fixed to the guide Gd.

  A fixed mold 15 is fixed to the fixed platen 11 and a movable mold 16 is fixed 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. Then, mold 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 resin (not shown) injected from the injection nozzle 18 of the injection device 17 is formed in the cavity space. Charged to A mold device 19 is configured by the fixed mold 15 and the movable mold 16.

  The suction plate 22 is fixed to the guide Gd in parallel with the movable platen 12. As a result, the suction plate 22 can move forward and backward behind the rear platen 13. The suction plate 22 may be formed of a magnetic material. For example, the suction plate 22 may be configured by an electromagnetic laminated steel plate formed by laminating thin plates made of a ferromagnetic material.

  The linear motor 28 is provided on the guide Gd in order to advance and retract the movable platen 12. The linear motor 28 includes a stator 29 and a mover 31, and the stator 29 is formed on the frame Fr in parallel with the guide Gd and corresponding to the moving range of the movable platen 12. Is formed at a lower end of the movable platen 12 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 magnetizing the N and S poles alternately and at the same pitch as the pole teeth 33. When the linear motor 28 is driven by supplying a predetermined current to the coil 35, the movable element 31 is advanced and retracted, and accordingly, the movable platen 12 is advanced and retracted by the guide Gd to perform mold closing and mold opening. it can.

  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.

  The movable platen 12 and the suction plate 22 are not limited to be fixed to the guide Gd, and a movable element 31 of the linear motor 28 may be provided on the movable platen 12 or the suction plate 22. Further, the mold opening / closing mechanism is not limited to the linear motor 28, and may be a hydraulic type or an electric type.

  When the movable platen 12 is moved forward and the movable mold 16 abuts against the fixed mold 15, the mold is closed and subsequently the mold is clamped. An electromagnet unit 37 is disposed between the rear platen 13 and the suction plate 22 in order to perform mold clamping. A center rod 39 extending through the rear platen 13 and the suction plate 22 and connecting the movable platen 12 and the suction plate 22 is disposed so as to freely advance and retract. The center rod 39 advances and retracts the suction plate 22 in conjunction with the advance and retreat of the movable platen 12 when the mold is closed and when the mold is opened, and the mold clamping force generated by the electromagnet unit 37 is applied to the movable platen 12 when the mold is clamped. introduce.

  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 center rod 39, and the like constitute the mold clamping device 10.

  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. Further, in the present embodiment, a groove 45 is formed around the center rod 39 in the predetermined portion of the rear end surface of the rear platen 13, and the core (inner pole) 46 and the groove 45 are located outside the groove 45. A yoke (outer pole) 47 is formed. A coil 48 is wound around the core 46 in the groove 45. In addition, the core 46 and the yoke 47 may be comprised by the integral structure of a casting, or may be comprised by the electromagnetic laminated steel plate formed by laminating | stacking the thin plate which consists of a ferromagnetic material.

  In the present embodiment, the electromagnet 49 may be formed separately from the rear platen 13, and the adsorption portion 51 may be formed separately from the adsorption plate 22, or the electromagnet may be adsorbed as a part of the rear platen 13 and adsorbed as a part of the adsorption plate 22. A part may be formed. Further, 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 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.

  The center rod 39 is connected to the suction plate 22 at the rear end and is connected to the movable platen 12 at the front end. Therefore, the center rod 39 is advanced together with the movable platen 12 when the mold is closed to advance the suction plate 22, and is retracted together with the movable platen 12 when the mold is opened to retract the suction plate 22. For this purpose, a hole 41 for penetrating the center rod 39 is formed in the central portion of the rear platen 13, and a bearing such as a bush that slidably supports the center rod 39 facing the opening at the front end of the hole 41. A member Br1 is provided.

  The driving of the linear motor 28 and the electromagnet 49 of the mold clamping device 10 is controlled by the control unit 60. The control unit 60 includes a CPU, a memory, and the like, and also includes a circuit for supplying 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 also connected to the control unit 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. . In the drawing, an example in which a load detector 55 is installed on two upper and lower tie bars 14 is shown. The load detector 55 is constituted by, for example, a sensor that detects the extension amount of the tie bar 14. The load detected by the load detector 55 is sent to the control unit 60. Note that the control unit 60 is omitted for the sake of convenience in FIG.

  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 controller 60. In the state of FIG. 2 (the state at the time of mold opening), the mold opening / closing processor 61 supplies current to the coil 35. Subsequently, the linear motor 28 is driven, the movable platen 12 is advanced, 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 unit 60 controls the mold clamping process. The mold clamping unit 62 supplies current to the coil 48 and attracts the attracting unit 51 by the attracting force of the electromagnet 49. Along with this, the clamping force is transmitted to the movable platen 12 through the suction plate 22 and the center rod 39, and clamping is performed. When changing the clamping force such as at the start of clamping, the clamping unit 62 generates a target clamping force to be obtained by the change, that is, a target clamping force in a steady state. Control is performed so that the necessary steady-state current value is supplied to the coil 48.

  The mold clamping force is detected by the load detector 55. The detected mold clamping force is sent to the control unit 60, where the current supplied to the coil 48 is adjusted so that the mold clamping force becomes a set value, and feedback control is performed. During this time, the 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 the supply of current to the coil 48 in the state of FIG. Along with this, the linear motor 28 is driven, the movable platen 12 is moved backward, and the movable mold 16 is placed in the retracted limit position as shown in FIG.

  Here, a characteristic configuration of the present invention will be described with reference to FIG.

  FIG. 3 is a single view of the rear platen 13 including the cooling water channel 70 according to one embodiment (first embodiment), and FIG. 3A is a plan view of the rear platen 13 viewed from the suction plate 22 side in the mold clamping direction. FIG. 3B is a cross-sectional view of the main part of the rear platen 13, and is a cross-sectional view along the line AA in FIG. FIG. 4 is a cross-sectional view schematically showing a magnetic circuit formed on the rear platen 13 and the suction plate 22. FIG. 4 schematically shows the flow of magnetic flux generated by the electromagnet unit 37 during mold clamping (the magnetic flux loop R in the suction plate 22 and the rear platen 13). That is, a loop that reaches the suction plate 22 from the core 46 via the gap δ, passes through the inside of the suction plate 22 and reaches the yoke 47 via the gap δ is defined.

  As described above, the rear platen 13 includes the groove 45 for accommodating the coil 48 on the surface on the suction plate 22 side. The cross-sectional shape and arrangement position of the groove 45 may be arbitrary.

  In the present embodiment, the rear platen 13 includes a cooling water passage 70 through which cooling water for cooling the coil 48 passes, as shown in FIG. The cooling water channel 70 is formed inside the rear platen 13. For example, the cooling water channel 70 may be formed by forming holes communicating with each other in each steel plate constituting the electromagnetic laminated steel plate. The cooling water channel 70 may be formed at an arbitrary position inside the rear platen 13. In the example shown in FIG. 3, the cooling water channels 70 are provided at both corners of the rear platen 13 in the vertical direction. As shown in FIG. 4, such a corner portion is not often used as a main magnetic circuit of the electromagnet unit 37, so that the cooling water channel 70 can be formed without substantially affecting the mold clamping force. it can.

  The cooling water channel 70 may be formed in any direction inside the rear platen 13. When the rear platen 13 is formed of an electromagnetic laminated steel plate, from the viewpoint of productivity, the cooling water channel 70 is preferably formed so as to extend in the lamination direction of the electromagnetic laminated steel plate (that is, configure the electromagnetic laminated steel plate). It extends in the direction perpendicular to each steel plate). In the example shown in FIG. 3, the rear platen 13 is formed of an electromagnetic laminated steel plate in which each steel plate is laminated in a horizontal direction perpendicular to the clamping direction (up and down direction of the paper surface of FIG. 3A). The cooling water channel 70 extends linearly along the lamination direction of the electromagnetic laminated steel plates.

  The cooling water passage 70 may be connected to a cooling water supply means (not shown) outside the rear platen 13. The cooling water supply means may include a pipe, a pump, a heat exchanger (radiator), and the like. The flow rate (flow velocity) of the water flowing through the cooling water channel 70 may be constant or variable. For example, the flow rate of water flowing through the cooling water channel 70 may be varied according to the temperature of the electromagnet unit 37, and may be varied according to the amount of heat (temperature) of the coil 48, for example. The temperature of the coil 48 may be detected using a thermistor or the like. In the cooling water channel 70, water may be circulated at all times during operation of the injection molding machine, or may be circulated when the temperature of the coil 48 exceeds a predetermined threshold.

  In this embodiment, when the electromagnet unit 37 is driven, the coil 48 generates heat. Heat from the coil 48 is transmitted to the inside of the rear platen 13 and transferred to the water flowing through the cooling water channel 70. In this manner, the cooling of the coil 48 can be effectively realized, and the burning of the coil 48 can be prevented.

  As described above, according to the first embodiment, by providing the cooling water channel 70 inside the rear platen 13, the heat from the coil 48 can be moved to the outside through the water in the cooling water channel 70, and the coil 48 is It can be cooled effectively. Moreover, since the cooling water channel 70 is formed inside the rear platen 13, no new space is required. Further, the cooling water channel 70 can be integrally formed in the electromagnetic laminated steel sheet, and in this case, it can be configured without using a copper tube, a cooling plate, or the like that can cause excitation interference. Further, the cooling water channel 70 can be formed inside the rear platen 13 by using a part that is not used as a magnetic circuit (or a part that does not greatly hinder the formation of the magnetic circuit). The necessary clamping force can be maintained without increasing the physique. In addition, since the cooling water channel 70 is formed inside the rear platen 13, it is possible to stabilize the temperature of the rear platen 13 by circulating water through the cooling water channel 70.

  FIG. 5 shows a single item view of the rear platen 13 including the cooling water channel 71 according to another embodiment (embodiment 2), and FIG. 5A is a plan view of the rear platen 13 viewed from the suction plate 22 side in the mold clamping direction. FIG. 5B is a cross-sectional view of the main part of the rear platen 13, and is a cross-sectional view taken along line AA in FIG.

  In the present embodiment, the cooling water channel 71 is formed immediately below the groove 45 so as to be formed on the back surface of the coil 48. That is, the cooling water channel 71 is provided at a position overlapping the groove 45 when viewed in the mold clamping direction (FIG. 5A). Note that the cooling water channel 71 may be formed so as to overlap the groove 45 as shown in FIG. 5A or may be formed so as to partially overlap the groove 45. Further, the distance between the cooling water channel 71 and the groove 45 (distance in the mold clamping direction) is arbitrary, but may be set as small as possible from the viewpoint of cooling efficiency.

  Also in the second embodiment, substantially the same effect as in the first embodiment can be obtained. Further, according to the second embodiment, the cooling water channel 71 is provided immediately below the coil 48, so that the coil 48 can be cooled more efficiently.

  The cooling water channel 71 according to the second embodiment can be used in combination with the cooling water channel 70 according to the first embodiment. FIG. 6 is a diagram illustrating an example of these combination modes, and is a cross-sectional view of the rear platen 13 and the suction plate 22. As shown in FIG. 6, a plurality of cooling water channels 70 and cooling water channels 71 may be formed on both sides. Also in this case, the cooling water channel 70 and the cooling water channel 71 may be provided so as not to substantially block the magnetic circuit (magnetic flux flow R).

  In the first and second embodiments, the “first fixed member” in the claims corresponds to the fixed platen 11, and the “first movable member” in the claims is the movable platen 12. Corresponding to The “second fixing member” in the claims corresponds to the rear platen 13, and the “second movable member” in the claims corresponds to the suction plate 22. However, as a modification, the electromagnet 49 may be provided on the suction plate 22 side and the suction portion may be provided on the rear platen 13 side. In this modification, the “second fixing member” corresponds to the suction plate 22, The “second movable member” in the claims corresponds to the rear platen 13.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, water is used as a cooling fluid, but a fluid other than water (for example, oil or gas) may be used.

  In the above-described embodiment, the cooling water channel 71 is formed inside the rear platen 13, but a similar cooling water channel may be formed inside the adsorption plate 22. This is because the suction plate 22 can also be heated by heat from the rear platen 13 due to the heat generated by the coil 48.

  In the above-described embodiment, the linear cooling water channel 71 is formed inside the rear platen 13, but the cooling water channel 71 may be bent in any direction inside the rear platen 13.

  In the above-described embodiment, the rear platen 13 is formed with the one-pole electromagnet 49. However, the rear platen 13 may be provided with an electromagnet so that a plurality of poles are formed (that is, multipolarization is possible). May be realized).

  In the above description, the mold clamping device 10 having a specific configuration is illustrated, but the mold clamping device 10 may have any configuration as long as the mold clamping is performed using an electromagnet.

Br1 bearing member Fr frame Gd guide 10 mold clamping device 11 fixed platen 12 movable platen 13 rear platen 14 tie bar 15 fixed mold 16 movable mold 17 injection device 18 injection nozzle 19 mold device 22 suction plate 28 linear motor 29 stator 31 movable Child 33 Magnetic pole teeth 34 Core 35 Coil 37 Electromagnet unit 39 Center rod 41 Hole 45 Groove 46 Core 47 Yoke 48 Coil 49 Electromagnet 51 Adsorption part 55 Load detector 60 Control part 61 Mold opening / closing processing part 62 Mold clamping part 70, 71 Cooling Waterway

Claims (3)

A first fixing member to which a fixed mold is attached;
A second fixing member disposed opposite to the first fixing member;
A first movable member to which a movable mold is attached;
A second movable member connected to the first movable member and moving together with the first movable member,
A mold clamping force generating mechanism for generating a mold clamping force with the second fixed member and the second movable member;
An electromagnet is formed on the second fixed member or the second movable member constituting the mold clamping force generating mechanism, and the inside of the second fixed member or the second movable member on which the electromagnet is formed. A fluid passage through which a cooling fluid passes ,
The second fixed member or the second movable member in which the fluid passage is formed is formed of an electromagnetic laminated steel plate, and the fluid passage is formed to extend in the lamination direction of the electromagnetic laminated steel plate. Features an injection molding machine. The second fixed member or the second movable member on which the electromagnet is formed includes a groove for accommodating a coil,
The injection molding machine according to claim 1, wherein the fluid passage is provided at a position overlapping the groove when viewed in a mold clamping direction.   The injection molding machine according to claim 1, wherein a flow rate of the cooling fluid flowing through the fluid passage is changed according to a temperature of the electromagnet.

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