JPH0232064B2 - SHASHUTSUSEIKEIKINOKATAJIMESOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a mold clamping device for an injection molding machine.

(B) Prior Art There are two types of mold clamping devices for conventional injection molding machines: a direct pressure type mold clamping device and a toggle type mold clamping device.
A direct pressure mold clamping device uses a large-diameter hydraulic cylinder to directly press the movable platen, and a toggle-type mold clamping device uses a toggle mechanism to double the pushing force of a relatively small-diameter hydraulic cylinder. It is designed to press the movable platen by force.

(c) Problems to be Solved by the Invention However, the mold clamping devices of conventional injection molding machines as described above are all driven using hydraulic pressure, and a seal is used to seal the hydraulic pressure. , sealing members, etc. are used, and these parts wear out as they are used, so it is necessary to periodically replace the parts, and in some cases, oil leakage accidents may occur and operation may be stopped. However, there were some aspects where productivity was not sufficient. In addition, there are problems in that the operating state changes depending on the oil temperature and lacks stability, and it is necessary to install a relatively large hydraulic cylinder.
Another problem was that the overall length of the mold clamping device became longer, making the device larger. The present invention solves the above-mentioned problems and provides a mold clamping device for an injection molding machine that does not require periodic replacement of packing, stops the device due to oil leakage accidents, etc., and has a more compact structure. The purpose is also to obtain.

(d) Means for solving the problems The present invention achieves the above object by operating a mold clamping device using a mold clamping electric motor and a mold opening/closing electric motor. That is, the mold clamping device for an injection molding machine according to the present invention includes a fixed plate fixed on a bed, and a movable plate arranged on the bed so as to face the fixed plate and movable in a direction toward or away from the fixed plate. a plate, four tie bars that penetrate the fixed plate and have screws on the outer periphery to prevent rotation;
a locking mechanism capable of connecting the tie bar to the movable platen; four first nut members each having a female thread that engages with the male threads of the four tie bars to form a first ball screw mechanism; 1. A thrust bearing and a holder that connect the nut member to the surface of the fixed plate opposite to the mold mounting surface so that the axial direction can be transmitted, a mold clamping electric motor provided on the bed or the fixed plate, and a mold clamping A mold clamping drive mechanism that can decelerate the rotation of an electric motor and transmit it to four nut members and drive them in a synchronized state, a mold opening/closing electric motor installed on the bed, and a mold opening/closing electric motor. Therefore, it has a rotary shaft that is rotationally driven and has a thread on its outer periphery, and a second nut member that meshes with the male thread of the rotary shaft fixed to the movable platen to constitute a second ball screw mechanism.

(E) Function With the above configuration, the mold can be opened and closed at high speed by controlling the rotational direction of the mold opening/closing motor, and the mold can be clamped by operating the mold clamping motor. Force can be applied and removed. Therefore, sufficient mold clamping force can be applied at high speed cycles without using a large-capacity electric motor. The mold clamping force by the mold clamping electric motor acts on the movable platen only when the mold has been closed by the operation of the locking mechanism. Therefore, no electromagnetic clutch is required to switch the operation of both electric motors. Furthermore, when replacing the mold, the tie bar can be moved from the periphery of the mold, making the mold replacement work easier.

(f) Examples Examples 1 to 10 of the attached drawings will be described below.
This will be explained based on the diagram.

A fixed platen 12 is fixed onto the bed 10 with bolts 14. A movable platen 16 is arranged to face the fixed platen 12, and the movable platen 16 is supported via a ball slider 20 to a rail 18 on the bed 10, as shown in FIG. It is possible to move toward or away from the stationary plate 12. A fixed mold 22 is attached to the fixed platen 12, and a movable mold 2 is attached to the movable plate 16.
4 can be installed. The fixed platen 12 is provided with a central hole 12a through which the injection unit 88 can enter. A tie bar 26 passes through each corner of the rectangular fixed plate 12. The tie bar 26 is supported by bushes 28 provided in each through hole of the stationary platen 12. A flange 30 having a larger diameter than the tie bar 26 is fixed to the end of the tie bar 26 on the movable platen 16 side. Further, the other end of the tie bar 26 is prevented from rotating by fitting the square cross section 32 into the square hole of the rotation prevention plate 34 (see FIG. 6). An escape hole 12b is provided on the die mounting side surface of the stationary platen 12 to accommodate the flange 30 at the tip of the tie bar 26. tie bar 26
A male thread 36 is formed on the outer periphery. Each male thread 36 is engaged with a first nut member 38 having a female thread. The male screw 36 and the first nut member 38 constitute a first ball screw mechanism. The first nut member 38 is connected to a holder 42 attached to the fixed platen 12 by a bolt 40.
It is rotatably supported with a thrust bearing 44 interposed between it and the stationary platen 12. A driven gear 48 is provided on each first nut member 38 by a bolt 46 so as to rotate together with the driven gear 48 . Each driven gear 48 meshes with an intermediate gear 50. As shown in FIGS. 4, 5, and 6, the intermediate gear 50 also meshes with a drive gear 52, and the drive gear 52 is rotated by a mold clamping electric motor 54 (a geared electric motor) provided on the bed 10. It is designed to be driven. In addition, the mold clamping electric motor 54
has an electromagnetic brake 56. Drive gear 5
2. The intermediate gear 50 and the driven gear 48 constitute a mold clamping drive mechanism. A second nut member 58 is attached to the lower part of the movable platen 16 with a bolt 60. The second nut member 58 is engaged with a male thread 64 on the outer periphery of the rotating shaft 62 to constitute a second ball screw mechanism. The rotating shaft 62 is rotatably supported by a bearing 68 attached to the bed 10 by a bearing case 66. Further, the rotating shaft 62 is connected to a mold opening/closing electric motor 70 fixed to the bed 10 via a coupling 72. The movable platen 16 has through holes 74 at positions corresponding to each tie bar 26. The through hole 74 has an inner diameter larger than the outer diameter of the flange 30. A locking plate 76 that is movable in the vertical direction is provided on the surface of the movable platen 16 opposite to the surface on which the movable die 24 is attached. The locking plate 76 is connected via a bracket 82 to a rod 80a of an electric cylinder 80 provided in a recess 78 in the upper part of the movable platen 16 (see FIG. 3). The locking plate 76 is
As shown in the figure, it has an escape hole 84 through which the two upper flanges 30 can pass, and a notch 86 that communicates with the escape hole 84. The cutout portion 86 is sized to allow the tie bar 26 to pass therethrough, but not to allow the flange 30 to pass therethrough. In addition, similar notches 86 are provided on the lower two tie bars 2.
6. The locking plate 76, the electric cylinder 80, and the flange 30 of the tie bar 26 constitute a locking mechanism.

Next, the operation of this embodiment will be explained. 1st
The figure shows the mold in an open state. When closing the mold from this state, the mold opening/closing electric motor 70 is driven to rotate the rotary shaft 62 via the coupling 72. As a result, the movable platen 16 is moved in the direction of the fixed platen 12 (to the right in FIG. 1) by the second ball screw mechanism constituted by the external screw 64 and the second nut member 58. In addition, at this time, flange 3
0 is stopped at a predetermined position depending on the thickness of the fixed mold 22 and the movable mold 24. In this way, the movable type 24
The movable platen 16 is moved until it contacts the fixed mold 22. As the movable platen 16 moves, the tie bar 26
The flange 30 at the tip of is connected to the through hole 74 of the movable platen 16.
When the fixed die 22 and the movable die 24 are in contact with each other, a small gap Δl is formed between the flange 30 and the locking plate 76, as shown in FIG. That is, the position of the flange 30 is
In order to form a gap Δl, the first
It is set by adjusting the rotational position of the nut member 38. Next, the electric cylinder 80 is operated from the state shown in FIG. 3 to the state shown in FIG. 9 (that is, the rod 80a is retracted and the locking plate 76 is lowered). As a result, each tie bar 26 fits into the notch 86, as shown in FIG. Next, the mold clamping electric motor 54 is driven, and the drive gear 52 and the intermediate gear 50
and each first nut member 38 via the driven gear 48
Rotate in sync. By doing this, due to the action of the first ball screw mechanism constituted by the first nut member 38 and the male screw 36,
The tie bar 26 moves to the right in FIG. 1, so that the gap Δl becomes 0, and by further rotating the mold clamping motor 54, a mold clamping force acts between the fixed mold 22 and the movable mold 24. . When the mold clamping force acting between the fixed mold 22 and the movable mold 24 reaches a predetermined value, the electromagnetic brake 56 is activated, and then the current to the mold clamping motor 54 is cut off.
to stop. Thereby, a predetermined mold clamping force is maintained. Next, the molten resin is injected into the mold cavity from the injection unit 88, and then the molded product is cooled. When cooling of the molded product is completed, the electromagnetic brake 56 is released, the mold clamping motor 54 is rotated in the opposite direction to the aforementioned rotation direction, the mold clamping force is removed, and the flange 30 and locking plate 7 are rotated.
6, the mold clamping electric motor 54 is stopped. Next, the electric cylinder 80 is operated to raise the locking plate 76 and release the flange 30 from the restrained state. Next, the mold opening/closing electric motor 70 is rotated in the opposite direction to that in the above case, and the movable platen 16 is moved in a direction away from the fixed platen 12. When the movable platen 16 moves to the position shown in FIG. 1, the mold opening/closing electric motor 70 is stopped and the molded product is taken out. This results in 1
The cycle ends and the same cycle is repeated.

When replacing the mold, drive the mold opening/closing motor 70 from the state shown in FIG. The mold clamping electric motor 54 is driven as it is, and the tie bar 26 is moved to the right in FIG. Flange 30 is escape hole 1
By moving the tie bar 26 until it is accommodated in the inside 2b, the state shown in FIG. 10 is achieved. In this state, the fixed mold 22 and the movable mold 24 are hung together by a crane or the like, and the connections with the fixed platen 12 and the movable platen 16 are released, respectively, and then the movable platen 1
The fixed mold 22 and the movable mold 24 can be removed by moving the mold 6 slightly to the left in FIG. At this time, since the tie bar 26 is not present around the fixed mold 22 and the movable mold 24, the movable mold 22 and the movable mold 24 can be taken out in any direction such as the vertical direction or the horizontal direction. When installing the mold, you can work in the reverse order of the above.

The mold clamping device of this injection molding machine uses a mold opening/closing electric motor 70 and a mold clamping electric motor 54 to perform the mold opening/closing operation and the mold clamping operation, and does not use a hydraulic cylinder, so there is wear and tear on the packing, sealing members, etc. There are no problems such as oil leaks or changes in operation due to oil temperature. Furthermore, since the stroke, movement speed, and mold clamping force of the movable platen 16 by the mold opening/closing electric motor 70 and the mold clamping electric motor 54 can be controlled, these can be easily controlled as desired using a general controller. It becomes possible to control. Furthermore, since there are no obstacles around the mold when replacing the mold, it is very easy to attach and remove the mold, and the working time can be shortened. In addition, in the mold closing process, the mold clamping electric motor 5
4 and the first ball screw mechanism do not operate, and the force from the mold clamping electric motor 54 is transmitted to the movable platen 16 only in the mold clamping process after mold closing is completed (that is, the locking mechanism is not activated). Therefore, there is no need for an electromagnetic clutch to release the mold clamping motor 54 while the mold opening/closing motor 70 is in operation, and no operating time is required for fastening and releasing the electromagnetic clutch. Cycle times can be shortened, and reliability is also improved since there is no need to consider failure of the electromagnetic clutch.

(G) Effects of the Invention As explained above, according to the present invention, the mold clamping operation and the mold opening/closing operation are performed by the mold clamping electric motor and the mold opening/closing electric motor, so that a hydraulic cylinder is not required. First, productivity is improved and the entire mold clamping device can be downsized. Furthermore, since two electric motors are used for mold clamping and mold opening/closing, a large capacity electric motor is not required. Furthermore, since no electromagnetic clutch is used, reliability is improved. In addition, mold replacement work has become easier.

[Brief explanation of drawings]

Fig. 1 is a diagram showing one embodiment of the present invention, Fig. 2 is a view seen in the direction of the arrow in Fig. 1, Fig. 3 is a sectional view taken along the - line in Fig. Figure -
5 is a sectional view taken along the - line in FIG. 4, FIG. 6 is a view taken in the direction of the arrow in FIG. 1, and FIG. 7 is a view of the mold clamping device shown in FIG. 1. A diagram showing the mold clamping state, Figure 8 is a view seen in the direction of the arrow in Figure 7, Figure 9 is a sectional view taken along the line - in Figure 8, and Figure 10 is the mold clamping device shown in Figure 1. It is a figure which shows the state at the time of mold exchange. 10...Bed, 12...Fixed plate, 14...Bolt, 16...Movable plate, 18...Rail, 20...
...Ball slider, 22...Fixed type, 24...
Movable type, 26... Tie bar, 28... Bushiyu, 3
0...Flange, 32...Rectangular cross section, 34...
Stopper plate, 36...Male thread, 38...First nut member, 40...Bolt, 42...Holder, 4
4... Thrust bearing, 46... Bolt, 4
8... Driven gear, 50... Intermediate gear, 52... Drive gear, 54... Mold clamping electric motor, 56... Electromagnetic brake, 58... Second nut member, 60... Bolt, 62... Rotating shaft , 64...male thread, 66...
Bearing case, 68...Bearing, 70...
...Electric motor for opening and closing the mold, 72...Coupling, 74
...Through hole, 76...Locking plate, 78
... recess, 80 ... electric cylinder, 82 ... bracket, 84 ... relief hole, 86 ... notch, 8
8...Injection unit.

Claims (1)

[Claims] 1. A fixed plate fixed on the bed, and a movable plate arranged on the bed so as to face the fixed plate and movable in a direction toward or away from the fixed plate;
Four tie bars that pass through the fixed plate and have screws on the outer periphery to prevent rotation, a locking mechanism that allows the tie bars to be connected to the movable plate, and a first ball that engages with the male threads of the four tie bars. The four first nut members having female threads constituting the screw mechanism and the four first nut members are connected so as to be able to transmit an axial force to the surface of the fixed plate on the opposite side from the mold mounting surface. A thrust bearing and a holder, a mold clamping motor installed on the bed or fixed plate, and a mold clamping device that can decelerate the rotation of the mold clamping motor and transmit it to four nut members to rotate them in a synchronized state. a drive mechanism for mold opening and closing, a motor for opening and closing the mold provided on the bed, a rotating shaft that is rotationally driven by the motor for opening and closing the mold and has a thread on its outer periphery, and a rotating shaft that is fixed to the movable platen and engages with the male thread of the rotating shaft. A mold clamping device for an injection molding machine, comprising: a second nut member that together constitutes a second ball screw mechanism.