JPS6264520A - Motorized mold clamping device - Google Patents

Abstract

PURPOSE:To provide a mold clamping device, in which a opening and closing of a mold is performed at high speed and yet normal mold clamping force can develop, by a method wherein the high speed opening and closing of the mold is done at high speed by means of toggle links and a motor-driven shifting device for opening and closing and the low pressure mold closing, heavy duty mold clamping and the like are done by means of a motor-driven pressurizing device, which is provided between a rear stationary platen and a pressure receiving platen. CONSTITUTION:A high speed mold closing is completed when toggle links 7a and 7a are brought in a straight line or in the completely stretched state. After the above-mentioned state is reached, a motor 10 is put into a low-speed and low-torque operation so as to rotate a rotary member 9 counterclockwise through gears 11 and 12. Said rotation of the rotary member 9 causes a screw tube 15 to push out leftwards and consequently a pressure receiving platen 6 and a movable platen 5 advance together with a double toggle 7 so as to close molds 21. After the completion of mold closing under low pressure is confirmed, the motor 10 is changed-over to a high-torque operation in order to develop heavy duty mold clamping force, which is immediately transmitted through the gears 11 and 12, the rotary member 9, the pressure receiving platen 6 and the toggle links 7a and 7a to the movable platen 5 in order to perform the heavy duty clamping of the molds 21.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an electric mold clamping device for an injection molding machine that uses a motor as a drive source.

[Prior Art] Generally, electric mold clamping devices use a drive device consisting of a motor, a feed screw, and a rotating member to convert the rotational motion of the motor into linear motion, thereby directly moving the movable platen forward and backward. This was used as a mold clamping force, or the mold was opened and closed by operating a toggle link linked to a movable platen, and the mold clamping force was generated by the extension of the toggle link.

[Problems to be Solved by the Invention] The mold clamping device requires high-speed mold opening and closing during mold opening and closing, and also requires strong mold clamping force after mold opening.

However, as mentioned above, when using a drive device with a motor, feed screw, rotating member, etc., in order to increase the speed, the lead of the feed screw must be increased, and the mold clamping force must be increased. In order to do this, the screw lead must be made smaller.

Therefore, in the past, the mold opening/closing speed was limited by the mold clamping force, making it impossible to increase the speed. This tendency was particularly problematic for large machines with a direct drive unit and movable platen connected together.

On the other hand, with mold clamping using toggle links, when the toggle links are fully extended, the tie bars are extended to generate mold clamping force, so if the mold thickness changes, the mold thickness will change accordingly. If the alignment is not accurate, the proper mold clamping force cannot be generated, and the mold clamping force is determined by the extension and expansion of the tie bars, but the mold and mechanical parts are also subject to compressive force, so the preset mold clamping allowance is The tie bars did not elongate as they were, and furthermore, the problem inherent to the toggle type remained that it was difficult to accurately grasp the mold clamping force because it was difficult for multiple tie bars to receive force uniformly.

[Means for solving the problem] This invention was conceived in view of the above circumstances, and its purpose is to be able to open and close the mold at high speed even though it is electrically operated, and to have a toggle mechanism. The object of the present invention is to provide a new mold clamping device that does not have the problem described above in J.

The present invention according to the above object comprises an opening/closing moving device comprising a motor, a screw shaft connected to the output shaft of the motor, and a movable crosshead on the toggle side meshing with the screw shaft, and the pressurizing S! The device is a short cylindrical rotating member with a gear on the outer end and a ball screw on the inner circumferential side on the rear fixed plate side, and a ball inserted in the rotating member and in a threaded groove on the outer periphery. The device is characterized in that it is comprised of a threaded cylinder on the back of the pressure receiving plate that meshes with a rotating member, and a motor that reciprocates the threaded cylinder via the rotating member.

Further, in the present invention, the screw shaft, motor, etc. of the opening/closing moving device can be arranged according to the structure of the toggle that connects the movable platen and the pressure receiving platen.

[Function] In the device with the above configuration, the mold is opened and closed at high speed by IMI! operated by a toggle link and a motor! 1. The mold is closed at high speed using a moving device, and low-pressure mold closing, strong mold clamping, etc. are performed by a motor-operated pressurizing device installed between the rear fixed plate and the pressure receiving plate. is transmitted to the movable platen via a toggle link.

The present invention will be specifically described below using a mold clamping device as shown in the drawings, in which an opening/closing moving device is disposed in parallel with the tie bar.

[Example] In the figure, 1.2 is a front fixing plate and a rear fixing plate that are installed oppositely on the machine base 3 at a required interval, and they are connected by tie bars 4.4 inserted at the four corners. .

The tie bars 4, 4 have a movable platen 5 and a hole 6a in the center.
The correct amount to have! lt6 is slidably inserted therethrough, and both panels are connected by a double toggle 7.

The rear stationary platen 3 has a large-diameter hole 8 in the center thereof, and a short cylindrical rotating member 9 is fitted into the hole 8. The outer end of this rotating member 9 is a gear 12 that meshes with the gear 11 of a mold clamping motor 10 attached to the rear stationary platen 3, and the inner circumference is threaded into which a ball 13 is fitted. be.

This rotating member 9 has a threaded groove 14 in which the ball 13 is accommodated.
A threaded cylinder 15 having a small lead on the outer periphery is engaged with the plurality of balls 13.

In addition, the tip of the screw cylinder 15 is connected to the back surface of the weight plate 6,
A motor 16 for opening and closing the mold is fixed to a seat plate 17 at the rear end.

The output shaft 18 of the motor 16 protrudes into the threaded cylinder 15, and a threaded shaft 19 formed by a ball screw with a large lead is connected to the drive shaft 18. This screw shaft 19
A cross head 20 located at the center of the double toggle 7 is screwed into the double toggle 7 through a large number of balls 13, and as the screw shaft 19 rotates, the cross head 20 reciprocates in the axial direction. There is.

Also, a crosshead 20 and two sets of toggle links 7a.

Links 7b, 7b are disposed between the toggle links 7a, 7a, and the toggle links 7a, 7a are expanded and contracted by the links 7b, 7b, and the mold is opened and closed by the movement of the movable platen 5.

Although not shown in the drawings, a stopper for regulating the position of the crosshead 20 is attached to the threaded portion of the screw shaft 19.

Next, the operation will be explained.

Mold Closing Operation In the mold open state shown in FIG. 1, the motor 16 is operated at high speed to rotate the screw shaft 19 counterclockwise.

This rotation causes the crosshead 20 to move forward (to the right) by the action of the ball screw. As the crosshead 20 moves, the angles of the links 7b, 7b change, and the toggle links 7a, 7
a is pushed open. This causes the toggle links 7a, 7a to extend, and the extension force is received by the movable platen 5! 16, but the pressure receiving plate 6 side does not move back due to the engagement of the rotating member 13 with the ball screw and the threaded cylinder 15, so the movable platen 5
Only the side moves forward and is fixed! The mold 21, which is divided and attached to the movable platen 82 and the movable platen 5, is closed at high speed.

Mold Clamping Operation The high-speed mold closing is completed when the toggle links 7a, 7a are fully extended and straight as shown in FIG. 2. Next, the motor 10 is operated at low speed and low torque. actuates and rotates the rotating member 9 counterclockwise via ll111.12. This rotation pushes the threaded cylinder 15 to the left, which causes the pressure receiving plate 6 and the movable plate 5 to move forward together with the double toggle 7, thereby closing the mold 21 as shown in FIG.

After confirming that mold closing by low pressure has been completed, the motor 10 is switched to high torque to generate strong mold clamping force. The strong mold clamping force is immediately applied to the teeth 1111.12, the rotating member 9,
Screw 1i115, pressure received! 16, Toggle link 7a, 7a
, movable! 15, where the mold 21 is strongly clamped.

Mold Opening Operation In the mold clamping state shown in FIG. 3, the motor 10 is rotated in the opposite direction to that during strong mold clamping. As a result, everything acts in the opposite direction to that during strong mold clamping, and strong mold opening occurs. When the motor 10 is stopped and the motor 16 is rotated in the opposite direction to the direction in which the mold is closed, the crosshead 20 moves backward and the toggle links 7b, 7b are bent inward, as shown in FIG. It contracts and moves the movable platen 5 backward. As a result, the mold 21 is opened at high speed.

In some cases, the motor 16 may be operated in advance, and the motor 10 may be operated before the mold opening is completed.

Also, to adjust the mold thickness, operate the motor 10 and receive pressure! This can be easily done by adjusting the position of 16.

Further, it is preferable to use a servo motor as the motor 10.1G, but any motor may be used as long as it can control the rotation speed and torque.

[Effects of the Invention] Since the present invention is configured as described above, the mold can be opened and closed at high speed by the toggle link and the motor, and low-pressure mold clamping, high-pressure mold clamping, and mold thickness adjustment can be performed by other motors. , mold thickness adjustment does not require much precision. ! lIt's easy to do. Furthermore, since the mold clamping force can be easily determined from the output of the motor, molding conditions can be set and checked reliably and easily, and productivity is improved.

Furthermore, by controlling the current value of the motor, a torque of υ1 m can be easily achieved, and the mold clamping force can be stabilized by performing force feedback control using a torque detector or the like. In addition, since the toggle link is used only for opening and closing the mold, there is less wear on the connecting bottle, etc.
Not only can the motor for II be made smaller, but the motor for powerful mold clamping also has a small movable stroke and does not require speed, so the screw lead can be made smaller, making it possible to make it more compact.

[Brief explanation of the drawing]

The drawings schematically show one embodiment of the electric mold clamping device according to the present invention, and FIG. 1 is a cross-sectional plan view when the mold is closed, and FIG.
The figure is a cross-sectional plan view when the mold is closed, and FIG. 3 is a cross-sectional plan view when the mold is clamped. 2...Front fixed plate 3...Rear fixed plate 4.
...Tie bar 5...Movable plate 6...Pressure plate 7...Double toggle 7a...Toggle link 9...Rotating member 10...Motor for mold clamping 13...Ball 14...・Thread groove
15...Threaded tube 16...Motor for opening/closing movement 11...Screw shaft 20...Crosshead Patent applicant Nikko Jushi Kogyo Co., Ltd.-1 "η Agent Akimoto l!1
M interim procedural amendment

Claims (1)

[Scope of Claims] A tie bar extending between a front fixed plate and a rear fixed plate arranged oppositely on the machine base, a toggle provided between a movable plate and a pressure receiving plate slidably inserted through the tie bar, and the toggle. A mold clamping device consisting of a device that opens and closes the movable platen via a toggle, and a device that is connected to the back of the pressure receiving plate and pressurizes the movable platen via a toggle. The pressurizing device is composed of a screw shaft connected to an output shaft and a movable crosshead on the toggle side that meshes with the screw shaft. a rotating member on the rear fixed plate side, a threaded cylinder on the back of the pressure receiving plate that is inserted into the rotating member and meshed with the rotating member through a ball in a threaded groove provided on the outer periphery; An electric mold clamping device comprising: a motor that reciprocates via a motor;