JPH09164570A - Double toggle type mold clamping apparatus and method for setting stop position of cross head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately obtain the position of the origin of a cross head even for an electric injection molding machine. SOLUTION: An apparatus has a movable platen 15, a toggle support 11 installed opposite to the platen 15, a double toggle type toggle mechanism which is installed between the platen 15 and the toggle support 11, a cross head 23 which is arranged freely movably forward and backward and actuates the toggle mechanism, a position detecting sensor for detecting the position of the cross head 23, and a regulation means for regulating the movement of the cross head 23 at a position to determine the origin of the sensor. Since a stop position can be set up by making the cross head 23 retreat from the position where the origin was determined, the position of the origin of the cross head 23 can be obtained correctly even for an electric injection molding machine, generating stable mold clamping force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double toggle type mold clamping device and a crosshead stop position setting method.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin heated and melted in a heating cylinder is charged (filled) into a cavity space of a mold device at a high pressure, and is cooled and solidified in the cavity space. By doing so, a molded product is obtained. The mold device includes a fixed mold and a movable mold, and the mold clamping device advances and retracts the movable mold and brings the movable mold into and out of contact with the fixed mold to perform mold closing, mold clamping, and mold opening. Is able to. Then, in the mold opening, the mold clamping device
The molded product is retracted while remaining in the movable mold, and subsequently, the ejector pin is advanced by the ejector device, the molded product is ejected, and the mold is released.

By the way, the mold clamping device has a toggle mechanism for advancing and retracting the movable mold. In the case of the double toggle type mold clamping device using the double toggle type toggle mechanism, the mold clamping device has a large toggle magnification. Can generate force. FIG. 2 is a schematic view of a conventional double toggle type mold clamping device. In the figure, reference numeral 10 denotes a double toggle type mold clamping device, and the double toggle type mold clamping device 10 is arranged so as to be movable back and forth along a tie bar 14, and is arranged to face the movable platen 15. Toggle support 1
1. A toggle lever 12 and a pin 32 which are swingably supported by the toggle support 11 about a pin 31.
Is connected to the toggle lever 12 and a movable platen 15 about a pin 33. The arm 13 is connected to a drive source (not shown). Arrow A by driving the drive source
The crosshead 17 and the pin 34 which are moved in and out in the direction
The toggle lever 18 is arranged so as to be swingable with respect to the toggle lever 12 with respect to the center, and swingably with respect to the crosshead 17 about the pin 35.

In the double toggle type mold clamping device 10 having the above structure, when the crosshead 17 is moved forward (moved to the right in the figure) by driving the driving source, the toggle lever 12 and the arm 13 are extended and set. The movable platen 15 can be moved forward by the mold clamping force of the toggle magnification. Further, when the crosshead 17 is retracted (moved to the left in the figure), the toggle lever 12 and the arm 13 are bent, and the movable platen 15 can be retracted.

Incidentally, S is a mold opening / closing stroke. By the way, in the double toggle type mold clamping device 10 having the above-mentioned configuration, at the dead point where the toggle lever 12 and the arm 13 extend completely, the toggle magnification theoretically becomes infinite, and a large mold clamping force can be generated. , A very large force is required when opening the mold, which causes a shock.

Therefore, the crosshead 17 is stopped at the stop position set slightly before the dead center, and the knicking amount (bending amount) a of the arm 13 is provided.

[0007]

However, in the conventional mold clamping device, in the case of a hydraulic injection molding machine,
Since the mold clamping cylinder is used as the drive source, the crosshead 17 can be accurately stopped at the stop position only by setting the stroke end of the mold clamping cylinder in correspondence with the stop position. In the case of an electric injection molding machine, since the servomotor is used as the drive source, the crosshead 17 cannot be stopped. Therefore, the origin position of the crosshead 17 can be accurately obtained, and the initial setting of the knicking amount becomes difficult. As a result, a stable mold clamping force cannot be generated.

The present invention solves the problems of the conventional mold clamping device, and even in the case of an electric injection molding machine, the origin position of the crosshead can be accurately obtained and the initial setting of the knicking amount can be performed. An object of the present invention is to provide a double toggle type mold clamping device that can be easily performed and can generate a stable mold clamping force, and a crosshead stop position setting method.

[0009]

Therefore, in the double toggle type mold clamping device of the present invention, a movable platen arranged so as to be movable back and forth, and a toggle support arranged so as to face the movable platen, A double toggle type toggle mechanism arranged between the movable platen and the toggle support, a crosshead arranged to move forward and backward, for operating the toggle mechanism, and a position for detecting the position of the crosshead. It has a detection sensor and a regulation means for regulating the movement of the crosshead at a position where the origin of the position detection sensor is obtained.

In the crosshead stop position setting method of the present invention, the crosshead is moved forward to extend the toggle lever and the arm of the toggle mechanism, and when the crosshead is pressed against the restricting means, the position detecting sensor operates. Perform home search and set the stop position by retracting the crosshead from the position where the home search was performed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view of a double toggle type mold clamping device according to an embodiment of the present invention. In the drawing, reference numeral 41 denotes a double toggle type mold clamping device, and the double toggle type mold clamping device 41 is arranged so as to be movable back and forth along the tie bar 14, and is arranged so as to face the movable platen 15. Toggle support 1
1. A double toggle type toggle mechanism (not shown) disposed between the movable platen 15 and the toggle support 11,
The cross head 23 is connected to a servo motor (not shown) and is moved back and forth in the direction of arrow A by driving the servo motor.

For this purpose, a ball nut 26 is fixed to the cross head 23 and is screwed with the ball nut 26.
The ball screw shaft 21 is rotatably arranged in the direction of arrow B by coupling the ball screw shaft 21 and the servo motor. The ball screw shaft may be fixed to the cross head 23 and the ball nut may be rotated. In the double toggle type mold clamping device 41 having the above structure, when the cross head 23 is moved forward (moved to the right in the figure) by driving the servo motor, the toggle lever 12
(See FIG. 2) and the arm 13 extend, and the movable platen 15 can be moved forward by the mold clamping force having the set toggle magnification. Further, when the crosshead 23 is retracted (moved to the left in the figure), the toggle lever 12 and the arm 13 are bent, and the movable platen 15 can be retracted.

A guide bar support 45 is provided integrally with the toggle support 11 and projects toward the movable platen 15 side.
The plurality of guide bars 28 are supported by. Rings 24a and 24b are disposed between the guide bars 28 at both ends of the guide bars 28, and the rings 24a and 24b are fixed to the guide bar support 45 by stoppers 25a and 25b. ing.
A screw stopper 29 is fixed to the front end of the ball screw shaft 21. The rings 24a and 24b and the stoppers 25a and 25b constitute a regulating means.

Usually, the crosshead 23 is provided with a ring 2.
It is moved in the direction of arrow A by the servo motor within a range not hitting 4a and 24b. And cross head 2
A position detection sensor (not shown) is provided to detect the position of No. 3. By the way, in controlling the position of the crosshead 23, it is necessary to determine the origin of the crosshead 23 so as to find the origin of the position detection sensor.
Therefore, first, the injection molding machine is switched to the origin search mode, and the servo motor is driven with low torque. Then, the toggle lever 12 and the arm 13 are extended until they are not normally used, and the crosshead 23 is brought into contact with the ring 24a. In this state, the position detection sensor is reset to perform origin search.

The distance from the mechanical origin position thus obtained to the position where the maximum mold clamping force is normally generated (preliminarily obtained by measurement) is given as an offset amount, and the result is obtained. The specified position is set as the origin position for control. In this way, the crosshead 2
By applying 3 to the ring 24a, the crosshead 23 is retracted from the position where the origin of the position detection sensor has been set, and the stop position is set.
Even in the case of an electric injection molding machine, the origin position of the crosshead 23 can be accurately obtained. Therefore, the initial setting of the knicking amount a (see FIG. 2) can be easily performed, and a stable mold clamping force can be generated.

Further, the crosshead 23 is connected to the ring 24.
Since the origin of the position detection sensor is set by hitting a, it is possible to generate a mold clamping force that does not differ for each model of the mold clamping device. The position detection sensor can be reset by an operator pressing an encoder reset button of a servo amplifier (not shown), but automatically when the crosshead 23 is applied to the ring 24a. You can also

It is also possible to bend the toggle lever 12 and the arm 13 and set the stop position of the crosshead 23 when the movable platen 15 is retracted. In that case, the crosshead 23 is moved forward from the position where the origin of the position detection sensor has been reached by applying the crosshead 23 to the ring 24b, and the stop position is set.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0019]

As described in detail above, according to the present invention, in the double toggle type mold clamping device, the movable platen is arranged so as to be movable back and forth, and is arranged so as to face the movable platen. A toggle support, a double toggle type toggle mechanism arranged between the movable platen and the toggle support, a crosshead which is arranged to move forward and backward, and operates the toggle mechanism, and a position of the crosshead. And a restricting unit that restricts the movement of the crosshead at a position where the origin of the position detecting sensor is obtained.

In this case, the crosshead can be moved forward to extend the toggle lever and the arm of the toggle support, and the origin of the position detection sensor can be set when the crosshead is pressed against the regulating means. Then, the stop position can be set by retracting the crosshead from the position where the origin has been set.

Therefore, even in the case of an electric injection molding machine, the origin position of the crosshead can be accurately obtained. As a result, the initial setting of the knicking amount can be easily performed, and a stable mold clamping force can be generated. In the crosshead stop position setting method of the present invention, the crosshead is moved forward to extend the toggle lever and the arm of the toggle mechanism, and when the crosshead is pressed against the restricting means, the origin of the position detection sensor is set. Then, set the stop position by retracting the crosshead from the position where the home search was performed.

Therefore, even in the case of an electric injection molding machine, the origin position of the crosshead can be accurately obtained. As a result, the initial setting of the knicking amount can be easily performed, and a stable mold clamping force can be generated.

[Brief description of the drawings]

FIG. 1 is a schematic view of a double toggle type mold clamping device according to an embodiment of the present invention.

FIG. 2 is a schematic view of a conventional double toggle type mold clamping device.

[Explanation of symbols]

 11 Toggle Support 12 Toggle Lever 13 Arm 15 Movable Platen 23 Crosshead 24a, 24b Ring 25a, 25b Stopper 41 Double Toggle Type Clamping Device

Claims (2)

[Claims] 1. A movable platen (a) arranged so as to be movable back and forth, (b) a toggle support arranged so as to face the movable platen, and (c) between the movable platen and the toggle support. A double toggle type toggle mechanism provided, (d) a crosshead that is arranged to move forward and backward, and operates the toggle mechanism, and (e) a position detection sensor that detects the position of the crosshead, (F) A double-toggle type mold clamping device, comprising: a restricting unit that restricts movement of the crosshead at a position where the origin of the position detection sensor is obtained. 2. (a) The crosshead is moved forward to extend the toggle lever and arm of the toggle mechanism, and (b) the origin of the position detection sensor is set when the crosshead is pressed against the regulating means. (C) A method of setting a stop position of a crosshead, which comprises setting a stop position by retracting the crosshead from a position where the origin has been set.