KR20130028003A - Injection molding machine - Google Patents

Abstract

PURPOSE: An injection molding device is provided to mount a mold when stopping a current supply to a coil of an electromagnet under a control of a control device. CONSTITUTION: An injection molding device comprises a first fixed member, a first movable member, a second movable member, a second fixed member, and a clamping force generation unit. A fixed mold is mounted on the first fixed member. A movable mold is mounted in the first movable member. The second movable member is moved with the first movable member. The second fixed member is installed between the first and second movable members. The clamping force generation unit generates a clamping force by an adsorption force caused by an electromagnet between the second fixed member and the second movable member. The clamping generation unit includes a current supply unit(100) and a control device(60). An electric circuit(200) supplying current to a coil is formed when stopping a current supply to the coil under a control of the control device.

Description

Injection molding machine

The present invention relates to an injection molding machine.

In an injection molding machine, a molten resin is injected from an injection apparatus, filled in a cavity of a mold apparatus, and solidified to mold a molded article. The mold apparatus comprises a stationary mold and a movable mold. Mold closing, mold clamping and mold opening of a mold apparatus are performed by a mold clamping apparatus.

As a mold clamping apparatus, a method 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 the response and stability are poor. Further, a bending moment is generated during operation of the toggle mechanism, and the mounting surface or the like for mounting the mold apparatus may be deformed.

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

International Publication No. 05/090052 Pamphlet

The mold apparatus is changed depending on the type of the molded article. When a new mold apparatus is mounted, the mold apparatus is temporarily fixed to the mounting surface with a bolt, and then the mold is closed. Instead of a bolt, a clamping device using hydraulic pressure or magnetic force may be used.

In this fixing operation, the door provided on the cover of the injection molding machine is opened and the current supply to the mold-clamping device is stopped when the door is open, in order to exclude malfunction caused by the control device.

In this state, the method using the toggle mechanism can maintain the mold force previously generated, but the mold using the electromagnet can not maintain the mold force. The supply of current to the coil of the electromagnet by the control device is interrupted. As a result, in the method using an electromagnet, the present fixing operation is difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an injection molding machine capable of mounting a mold apparatus in a state in which current supply to a coil of an electromagnet is stopped under control by a control apparatus.

In order to achieve the above object, an injection molding machine according to one aspect of the present invention comprises:

A first fixing member to which the fixed mold is mounted;

A first movable member to which the movable mold is mounted;

A second movable member that moves together with the first movable member,

A second fixing member provided between the first movable member and the second movable member,

And a mold clamping force generating mechanism for generating a mold clamping force between the second fixing member and the second movable member by an attraction force by an electromagnet,

Wherein the mold clamping force generating mechanism includes a current supplying section for supplying a current to the coil of the electromagnet and a control device for controlling the current supplying section,

And an electric circuit for supplying a current to the coil in a state in which the supply of current to the coil by the current supply unit under the control of the control unit is stopped is formed.

According to the present invention, there is provided an injection molding machine capable of mounting a mold apparatus in a state in which current supply to a coil of an electromagnet under control by a mold clamping apparatus is stopped.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a state of an injection molding machine when mold closing according to one embodiment of the present invention; Fig.
Fig. 2 is a view showing a mold starting state of an injection molding machine according to an embodiment of the present invention. Fig.
3 is a diagram showing a circuit for supplying a current to a coil of an electromagnet of an injection molding machine according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and a description thereof will be omitted. Further, the moving direction of the movable platen when mold closing is referred to as the forward direction, and the moving direction of the movable platen when the mold opening is performed will be referred to as rear.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a state of an injection molding machine when mold closing according to one embodiment of the present invention; Fig. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an injection molding machine, and more particularly to an injection molding machine, FIG.

In the drawing, reference numeral 10 denotes a mold-clamping apparatus, Fr denotes a frame of an injection molding machine, Gd denotes a guide consisting of two rails laid on the frame Fr, and 11 denotes a stationary platen (first fixing member). The stationary platen 11 may be formed on a position adjusting base Ba which is movable along a guide Gd extending in the mold opening and closing direction (left and right direction in the drawing). However, the stationary platen 11 may be placed on the frame Fr.

A movable platen (first movable member) 12 is provided so as to face the fixed platen 11. [ The movable platen 12 is fixed on the movable base Bb and the movable base Bb is movable on the guide Gd. As a result, the movable platen 12 is movable in the mold opening / closing direction with respect to the stationary platen 11. [

A rear platen (second fixing member) 13 is provided at a predetermined distance from the stationary platen 11 and in parallel with the stationary platen 11. [ The rear platen 13 is fixed to the frame Fr through the leg portion 13a.

Between the stationary platen 11 and the rear platen 13, a tie bar 14 (only two of the four tie bars 14 in the figure) is provided as four connecting members. The stationary platen 11 is fixed to the rear platen 13 through the tie bar 14. [ The movable platen 12 is installed so as to be movable forward and backward along the tie bars 14. A guide hole (not shown) for passing the tie bar 14 is formed at a position corresponding to the tie bar 14 in the movable platen 12. [ However, instead of the guide hole, a cutout may be formed.

A not shown thread is formed on the front end portion (the right end portion in the drawing) of the tie bar 14 and the nut n1 is screwed on the threaded portion so that the front end of the tie bar 14 is fixed to the stationary platen 11). The rear end portion of the tie bar 14 is fixed to the rear platen 13.

A stationary mold 15 is mounted on the stationary platen 11 and a movable mold 16 is mounted on the movable platen 12. The stationary mold 15 and the movable mold 12 16 are connected and disconnected, and mold closing, mold clamping, and mold clamping are performed. As a result of the mold clamping, a cavity (not shown) is formed between the stationary mold 15 and the movable mold 16, and a molten resin (not shown) injected from the injection nozzle 18 of the injection apparatus 17 Is filled in the cavity space. The mold apparatus (19) is constituted by the stationary mold (15) and the movable mold (16).

The attracting plate 22 (second movable member) is provided in parallel with the movable platen 12. The attracting 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 forward and backward from the rear platen 13. The attracting plate 22 may be formed of a magnetic material. However, the mounting plate 27 may be omitted. 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 and connected to the movable platen 12 at the front end. Thus, the rod 39 is advanced as the adsorption plate 22 advances at the time of mold closing, advances the movable platen 12, and is retracted as the adsorption plate 22 is retreated at the mold start, . Thereby, a hole 41 for penetrating the rod 39 is formed in the central portion of the rear platen 13.

The linear motor 28 is a type opening / closing drive unit for moving the movable platen 12 forward and backward, for example, between the attraction plate 22 connected to the movable platen 12 and the frame Fr. However, the linear motor 28 may be provided 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 in correspondence with the movement range of the slide base Sb. The movable element 31 is opposed to the stator 29 at the lower end of the slide base Sb and is formed over a predetermined range.

The mover 31 includes a core 34 and a coil 35. The core 34 has a plurality of magnetic pole teeth 33 formed at a predetermined pitch so as to protrude toward the stator 29 and the coils 35 are wound around the magnetic pole teeth 33. [ However, the magnetic pole teeth 33 are formed parallel to each other in a direction perpendicular to the moving direction of the movable platen 12. [ The stator 29 has a core (not shown) and a permanent magnet (not shown) extending on the core. The permanent magnet is formed by alternately magnetizing the magnetic poles of the N pole and the S pole. And a position sensor 75 for detecting the position of the movable element 31 is disposed.

When the linear motor 28 is driven by supplying a predetermined current to the coil 35, the mover 31 is moved forward and backward. As a result, the attracting plate 22 and the movable platen 12 are advanced and retreated, so that mold closing and mold opening can be performed. 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.

However, in this embodiment, the permanent magnet is provided on the stator 29 and the coil 35 is provided on the mover 31, but a coil may be provided on the stator and a permanent magnet may be provided on the mover. 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.

However, instead of the linear motor 28, a ball screw mechanism or the like for converting the rotational motion of the rotary motor and the linear motor into linear motion may be used as the mold opening / closing drive unit.

The electromagnet unit 37 generates a clamping force between the rear platen 13 and the attracting plate 22 by the attraction force of the electromagnet. This attraction force is transmitted to the movable platen 12 through the rod 39. [

It should be noted that the mold clamping device 10 (10) is fixed by the fixed platen 11, the movable platen 12, the rear platen 13, the attracting plate 22, the linear motor 28, the electromagnet unit 37, ). Further, a mold-clamping force generating mechanism is constituted by the electromagnet unit 37 or the like. The mold clamping force generating mechanism includes a current supplying section 100 (see FIG. 3) for supplying a current to the coil 48 of the electromagnet 49 and a control device 60 for controlling the current supplying section 100.

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

In this embodiment, however, the electromagnet 49 is formed separately from the rear platen 13, and the attracting portion 51 is formed separately from the attracting plate 22. However, as the portion of the rear platen 13, , And the adsorption portion may be formed as a part of the adsorption plate (22). The arrangement of the electromagnet and the adsorption portion may be reversed. For example, the electromagnet 49 may be formed on the adsorption plate 22 side and the adsorption unit 51 may be formed on the rear platen 13 side.

In the electromagnet unit 37, when a current is supplied to the coil 48, the electromagnet 49 is driven to adsorb the adsorption unit 51, thereby generating a clamp force.

The driving of the linear motor 28 and the electromagnet 49 of the mold clamping apparatus 10 is controlled by the control device 60. [ The control device 60 includes a CPU and a memory 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. To the control device 60, a load detector 55 is connected. The load detector 55 detects the load of the tie bar 14 at a predetermined position (a predetermined position between the stationary platen 11 and the rear platen 13) of the at least one tie bar 14 in the mold- And detects a load applied to the tie bar 14. The load detector 55 is constituted by, for example, a sensor for detecting the amount of extension of the tie bars 14. The load detected by the load detector 55 is sent to the control device 60. [

3, the control device 60 is connected to a current supplying part (driver) 100 for supplying a current to the coil 48 of the electromagnet 49, and controls the current supplying part 100. [ The control of the current supply unit 100 is performed by a mold clamping unit 62 described later.

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

The electric current supplying part 100 may include an unillustrated open / close monitoring switch for turning ON the electric current to the coil 48 of the electromagnet 49 only when the door provided on the cover of the injection molding machine is closed. When the open / close monitoring switch is turned OFF, current supply to the coil 48 of the electromagnet 49 by the current supply unit 100 is cut off.

However, the open / close monitoring switch may not be included in the current supply unit 100, but may be connected to the control unit 60. [ In this case, the controller 60 cuts off the current supply to the coil 48 of the electromagnet 49 by the current supplying unit 100 when the state of the open / close monitoring switch becomes the OFF state.

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

Closing process of the control device 60 is controlled by the mold opening / In the state (open state) of Fig. 2, the mold opening / closing processing section 61 supplies current to the coil 35 to drive the linear motor 28. Fig. The movable platen 12 advances to bring the movable mold 16 into contact with the stationary mold 15 as shown in Fig. At this time, a gap (?) Is formed between the rear platen (13) and the attracting plate (22), that is, between the electromagnet (49) and the attracting portion (51). However, the force required for mold closing is sufficiently small compared with the clamping force.

Next, the mold-clamping processing unit 62 of the control device 60 controls the mold-clamping process. The mold clamping processing unit 62 supplies a current to the coil 48 of the electromagnet 49 to attract the attracting unit 51 to the electromagnet 49. [ Thus, the clamping force is transmitted to the movable platen 12 through the attraction plate 22 and the rod 39, and the clamping force is applied.

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 part 62 controls the current supply part 100 so as to set the mold clamping force to a set value to adjust the current supplied to the coil 48 to perform feedback control. The melted molten resin in the injection apparatus 17 is injected from the injection nozzle 18 and charged into the cavity of the mold apparatus 19. [

When the resin in the cavity space is cooled and solidified, the mold opening / closing processing section (61) controls the mold opening process. The mold clamping processing unit 62 stops the supply of current to the coil 48 of the electromagnet 49 in the state shown in Fig. As a result, the linear motor 28 is driven to move the movable platen 12 backward, and the movable mold 16 is retracted and molded as shown in Fig.

Next, the mold thickness adjustment at the time of replacement of the mold apparatus 19 will be described.

When the new mold apparatus 19 is mounted according to the replacement of the mold apparatus 19, the thickness of the mold apparatus 19 is changed, and at the time when the mold closing is completed, the mold is formed between the rear platen 13 and the attracting plate 22 The gap < RTI ID = 0.0 >

Therefore, the injection molding machine is provided with the mold thickness adjusting device 70 for adjusting the gap? In accordance with the thickness of the mold apparatus 19. [ The mold thickness adjusting device 70 is constituted by a mold thickness adjusting motor 71, a gear 72, a nut 73, a rod 39 and the like. The rod 39 passes through a central portion of the attracting plate 22 and a screw 43 is formed at the rear end of the rod 39. [ A screw 43 and a nut 73 rotatably supported with respect to the attracting plate 22 are screwed together. A large-diameter gear (not shown) is formed on the outer circumferential surface of the nut 73, and this gear is meshed with a small-diameter gear 72 mounted on the output shaft 71a of the mold thickness adjusting motor 71. The nut 73 and the screw 43 constitute the motion direction converting section and the rotational motion of the nut 73 is converted into the rectilinear motion of the rod 39 in the moving direction converting section.

When the nut 73 is rotated by a predetermined amount with respect to the screw 43 by driving the mold thickness adjusting motor 71 in accordance with the thickness of the mold apparatus 19, the position of the rod 39 relative to the attracting plate 22 The position of the attracting plate 22 with respect to the stationary platen 11 and the movable platen 12 is adjusted so that the gap delta can be set to an optimal value. That is, the mold thickness is adjusted by changing the distance between the movable platen 12 and the attracting plate 22 in the mold opening / closing direction (lateral direction in the drawing).

The mold thickness adjusting motor 71 may be a servo motor or an encoder unit 71b. The encoder unit 71b detects the amount of rotation of the output shaft 71a 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 delta becomes a set value.

Next, mounting of the mold apparatus 19 will be described.

When the new mold apparatus 19 is mounted, the mold apparatus 19 is temporarily fixed to the stationary platen 11 in a state of being suspended by a crane or the like. Thereafter, the movable platen 12 advances to contact the mold apparatus 19, and then the mold apparatus 19 is shaped. The stationary mold 15 is fixed to the stationary platen 11 and the movable mold 16 is fixed to the movable platen 12 with bolts. Instead of a bolt, a clamping device using hydraulic pressure or magnetic force may be used.

The present fixing operation is performed by opening the door provided on the cover of the injection molding machine so that the current supply part 100 stops supplying the current to the coil 48 of the electromagnet 49 ). So as to exclude malfunction caused by the control device (60).

The stop state is automatically controlled such that the drive control of the drive source (for example, including the electromagnet 49, the linear motor 28, and the mold thickness adjusting motor 71) whose operation is feedback-controlled based on the detection results of various detectors is automatically The stopped 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 stationary state.

3, the electric circuit 200 connects the coil 48 of the electromagnet 49 and the DC power source (for example, the charger) PW to the electromagnet 49 independently of the current supplying unit 100, . The electric circuit 200 is different from the current supplying unit 100 and is not connected to the controller 60 and is not controlled by the controller 60. [

The electric circuit 200 supplies current to the coil 48 of the electromagnet 49 so that the electromagnet 49 adsorbs the attracting portion 51. Thus, the clamping force is transmitted to the movable platen 12 through the attraction plate 22 and the rod 39, and the clamping force is applied. Therefore, the mold clamping force can be generated in the stopped state, and the mold can be fixed.

The electric circuit 200 is constituted by, for example, a manual switch 202, a gap monitoring switch 204, and a variable resistor 206 or the like. The current of the current value corresponding to the resistance value of the variable resistor 206 is applied to the coils 48 of the electromagnet 49 when both the manual switch 202 and the gap monitoring switch 204 are ON, 48, so that the electromagnet 49 adsorbs the adsorbing portion 51.

The manual switch 202 is a switch that is manually switched to an ON state that permits current supply to the coil 48 of the electromagnet 49 and a prohibited OFF state. The supply of electric current by the electric circuit 200 can be started and terminated by the user's intention.

The gap monitoring switch 204 is turned ON to allow current supply only when the gap delta formed between the electromagnet 49 and the attracting portion 51 is equal to or smaller than the predetermined value 0 and the gap? Quot; 0 ", the current supply is inhibited. The electric current is supplied by the electric circuit 200 only when the gap delta is equal to or smaller than the predetermined value o0 so that the electromagnet 49 is attracted to the attracting plate 22 and the movable platen 12, the movable mold 16, and the like. The predetermined value? 0 is set within a range of 1.0 mm to 1.5 mm, for example.

The gap monitoring switch 204 may be an operation switch provided on the rear platen 13 side and operated by an operating piece provided on the suction plate 22. [ Also, the gap monitoring switch 204 may be an electromagnetic contactor or the like which is switched to the ON state and the OFF state in accordance with the operation of the operation switch.

However, the arrangement of the operation switch and the operation piece may be reversed, 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. Instead of the operation switch, a non-contact type proximity switch may be used.

The variable resistor 206 varies the current value of the current supplied to the coil 48 of the electromagnet 49, and the resistance value is changed manually. As the resistance value is lowered, the current value rises and the attracting force of the electromagnet 49 becomes stronger. Therefore, it is possible to adjust the mold clamping force by using the variable resistor 206. [

Next, a mounting method (fixing operation) of the mold apparatus 19 using the injection molding machine having the above-described configuration will be described.

First, after the temporary fixing operation, the linear motor 28 is driven so that the movable platen 12 is brought into contact with the movable mold 16. At this time, the gap? (> 0) formed between the electromagnet 49 and the attracting portion 51 becomes equal to or smaller than the predetermined value? 0, and the gap monitoring switch 204 is turned on. After the linear motor 28 is driven or before the drive so that the gap δ is equal to or smaller than the predetermined value δ0, the mold plate thickness adjusting device 70 is used between the suction plate 22 and the movable platen 11. You may adjust the distance.

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

Subsequently, electric current is supplied to the coil 48 of the electromagnet 49 by the electric circuit 200. First, the manual switch 202 is turned on, and then the resistance value of the variable resistor 206 is gradually lowered, and the current value flowing into the coil 48 is gradually increased to the set value. The electromagnet 49 adsorbs the adsorption section 51 and the mold clamping force is transmitted to the movable platen 12 through the adsorption plate 22 and the rod 39 to be shaped. Therefore, it is possible to perform the fixing operation in the mold-shaped state.

Although the 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 embodiments without departing from the scope of the present invention .

For example, the electric circuit 200 of the above embodiment allows electric current to be supplied to the coil 48 of the electromagnet 49 when the injection molding machine is in a stopped state, and current supply to the coil 48 when the stop state is released A switch for inhibiting the operation of the switch may be included. Both the electric circuit 200 and the electric current supply part 100 can be prevented from supplying current to the coil 48 of the electromagnet 49 at the same time.

10 clamping device
11 Fixing 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 (Molding Force Generator)
48 coils
49 electromagnet
60 control device
100 current supply
200 electric circuit
204 Gap monitoring switch
206 variable resistor

Claims (3)

A first fixing member to which the fixed mold is mounted;
A first movable member to which the movable mold is mounted;
A second movable member that moves together with the first movable member,
A second fixing member provided between the first movable member and the second movable member,
And a mold clamping force generating mechanism for generating a mold clamping force between the second fixing member and the second movable member by an attraction force by an electromagnet,
Wherein the mold clamping force generating mechanism includes a current supplying part for supplying a current to the coil of the electromagnet and a control device for controlling the current supplying part,
And an electric circuit for supplying current to the coil in a state in which the supply of current to the coil by the current supply unit under the control by the control apparatus is stopped
Injection molding machine characterized in that. The method according to claim 1,
Wherein the electric circuit includes a variable resistor for varying a current value of a current supplied to the coil
Injection molding machine characterized in that. The method according to claim 1 or 2,
Wherein the electric circuit permits supply of current to the coil when the gap formed between the electromagnet and the attracting portion adsorbed to the electromagnet is not more than a predetermined value and controls the supply of current to the coil when the gap exceeds a predetermined value Including prohibited switches
Injection molding machine characterized in that.

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