JPS623917A - Mold clamping device - Google Patents

Abstract

PURPOSE:To obtain a mold clamping device, the mold opening and closing speed of which is fast and at the same time the mold clamping force of which is large even when a small capacity motor is employed, by a structure herein an actuator, which generates the force and displacement in proportion to the quantity of electricity. CONSTITUTION:Firstly, a ball screw shaft 15 is advanced rightwards through a transmission mechanism consisting of a timing belt 12 and pulleys 13 and 14 by means of the rotation of a servomotor 11 so as to abut a moving mold 21 against a stationary mold 18 at their mating mold surfaces A. Secondly, when the predetermined voltage is applied to a piezoelectric actuator 19, the piezoelectric actuator 19 tends to elongate itself axially, though the dimension between the mold 21 and the pulley 14 is restricted, and consequently the molds 18 and 21 are more strongly clamped with each other through wedge action. When a braking mechanism 22 is applied before the application of the voltage to the piezoelectric actuator 19, no slackness develops and consequently more effective mold clamping can be done.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a mold clamping device for an injection molding machine or the like that opens and closes a mold using an electric motor.

[Prior art and its drawbacks]

When rotating a ball screw using a servo motor, etc. and converting rotational motion into linear motion to open and close a mold or generate mold clamping force, productivity can be increased by maintaining a fast mold opening/closing speed and generating a large mold clamping force. This is important, but conventionally, this required a large-capacity electric motor. In other words, in order to obtain a large mold clamping force, it is effective to increase the rotational reduction ratio and increase the torque, but on the other hand, the speed is low and the mold opening/closing time takes longer, which ultimately reduces productivity. Become. On the other hand, if the mold opening/closing time is shortened, the reduction ratio becomes small and a large mold clamping force cannot be obtained, which are contradictory drawbacks.

[Purpose of bacterial load]

SUMMARY OF THE INVENTION An object of the present invention is to provide a mold clamping device for an injection molding machine driven by an electric motor, which eliminates the above-mentioned drawbacks and can obtain a large mold clamping force even with a small-capacity electric motor. That is, it is a mold clamping device for an injection molding machine that opens and closes the mold using an electric motor that has a fast mold opening/closing speed and can provide a large mold clamping force.

[Components of the invention]

In order to achieve the above-mentioned purpose, in a mold clamping device such as an injection molding machine that uses an electric motor to open and close the mold, the amount of electricity between the mold opening and closing mechanism and the moving plate or between the moving mold after the mold is closed is The actuator that generates force and displacement was set up as a mud clamping device. The mold clamping device is equipped with a brake mechanism that keeps the force or displacement that is generated at a certain point constant.

〔Example〕

Next, one embodiment of the present invention will be explained with reference to FIG.
is a servo motor, and this rotational power is generated by the timing belt 12.
is transmitted to the ball screw shaft 15 via the pulleys 13 and 14. Since the ball screw shaft 15 is supported by a base ring 16 and is engaged with the pulley 14 which rotates but cannot move in the axial direction, the electric motor 11
The rotational movement becomes a linear movement in the axial direction of the ball screw shaft 15, and moves the movable mold 21 attached to the movable plate 20, which is connected to the fixed mold 18 attached to the fixed plate 17 via a piezoelectric actuator 19, back and forth. It is designed to open and close the mold. The piezoelectric actuator 19 is designed to expand in the axial direction depending on the applied voltage value. Therefore, when a voltage is applied to the piezoelectric actuator 19 after the molds 18 and 21 have come into contact with each other at the upper surface A of the mold assembly, Boo I
J ] 4 extends in the axial direction between the moving plates 20, so the molds 18 and 21 are clamped more strongly than before. 22 is a brake mechanism which
4 and the housing plate 230 to stop the rotation of the pulley 4. After the molds 18 and 21 come into contact with each other at the mold assembly A, the pulley 14 stops the rotation of the pulley 4 when generating mold clamping force. It is designed to hold its grip so that it does not loosen.

゛ [Operation] - The structure is as explained above, and the rotation of the servo motor 1 drives the ball screw shaft 15 through the transmission mechanism of the timing bell 12 and pulleys 13 and 14.
moves to the right in the figure, and the movable mold 21 contacts the fixed mold 18 at the mold mating surface A. Next, when a predetermined voltage is applied to the piezoelectric actuator 19, the piezoelectric actuator 19 tries to extend in the axial direction even though the dimension between the mold 21 and the pulley 14 is restricted, and as a result, For imitation purposes, the molds 18 and 2] are clamped even more strongly. If the brake mechanism 22 is activated before applying the voltage to the piezoelectric actuator 19', the mold can be clamped more effectively.

[Function and effect]

Because the action is performed with the configuration explained above, the electric motor is small, so the mold clamping operation is fast, and the mold clamping force is strong due to the piezoelectric actuator, so the mold can be clamped without using a large-capacity electric motor. A mold clamping device with large force can be obtained at low cost, the molding cycle can be shortened, and productivity can be increased.

In the above explanation, the case where the ball screw shaft is directly attached to the movable plate was explained, but it is of course effective even if the mold clamping mechanism is a toggle mechanism. A piezoelectric actuator may also be inserted between the movable plate and the movable mold.

[Brief explanation of the drawing]

``The first white diagram shows one embodiment of the present invention. ``11... Servo motor, 1... Timing belt, 13, 1.4... Pulley, 15... Ball screw shaft, 17...・Fixed plate, 18・・Fixed mold, 19・
・Piezoelectric actuator, 20... Moving plate, 21.
・・Moving mold, 22・Brake mechanism, 23・・Housing plate,

Claims (1)

[Claims] 1. In a mold clamping device such as an injection molding machine that opens and closes the mold using an electric motor, force is generated between the mold opening/closing mechanism and the moving plate or between the moving mold due to the amount of electricity after the mold is closed. A mold clamping device characterized by being provided with an actuator that generates displacement. 2. The mold clamping device according to claim 1, which includes a brake mechanism that continues to maintain the force or displacement generated by the actuator.