JP2003291191A - Mold pressing force adjusting method for toggle type mold clamping device, and toggle type mold clamping device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent a pressing force applied to dies from changing even when sliding resistance that may occur when moving a mold clamping mechanism changes over time. SOLUTION: A mold thickness adjusting motor 9 is driven to move mold clamping mechanisms 4, 5, and 18 in a direction approaching a fixed platen 21 so that a fixed mold 22a and a movable mold 22b touch each other. During the process, the crosshead 3 is moved by the reaction force of the pressing force generated between the molds 22a and 22b.
The servo motor 1 is driven so as to maintain the crosshead 3 at a predetermined position with respect to the end housing 18 against the torque applied to the servo motor 1 by being pressed in the direction approaching the reference numeral 8. A torque detecting device (not shown) detects whether the torque generated by the servo motor 1 against the torque has reached a predetermined value set by a setting device (not shown), and reaches a predetermined value. When it is detected that the operation has been performed, the mold thickness adjusting motor 9 is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold pressing force adjusting method for a toggle type mold clamping device used in combination with an injection molding machine, and a toggle type mold clamping device.

[0002]

2. Description of the Related Art An injection molding machine forms a product having a desired shape by injecting a molten resin at a high pressure into a cavity of a mold which is closed. Therefore, the injection molding machine needs a mold clamping device that can apply a sufficient mold clamping force so that the high-pressure molten resin does not leak from the mold. This mold clamping device is required to have a function capable of freely changing the mold clamping force depending on the mold used, resin, injection conditions, etc. As this mold clamping device, a so-called toggle type mold clamping device is widely used. There is.

FIG. 1 is a view showing a structure of a general toggle type mold clamping device in a partially broken state, and FIG. 2 is a view of the toggle type mold clamping device shown in FIG. 1 from the direction of arrow A in FIG. It is the figure seen.

The toggle type mold clamping device includes a fixed plate 21 to which a fixed mold 22a is attached, a movable plate 4 to which a movable mold 22b is attached, and a toggle link mechanism 5 on the movable plate 4. And an end housing 18 connected to each other. The fixed platen 21 is fixed on the bed 17, and the movable platen 4 and the end housing 18 are movable on the bed 17 in the axial direction.

The fixed plate 21 and the end housing 18 are
They are connected at their four corners by four parallel tie bars 15. One end of each of the tie bars 15 is fixed to the fixed platen 21, and a tie bar screw 16 is formed at the other end of the movable platen 4 and the end housing 18. The tip side of the tie bar screw 16 is screwed to the tie bar screw nut 13. Therefore, by rotating the tie bar screw nut 13 as needed, the end housing 18 can be moved along the tie bar 15 in the axial direction by a required distance. That is, depending on the amount of rotation of the tie bar screw nut 13, the end housing 18 can be moved toward the fixed platen 21 or away from the fixed platen 21. A driven gear 12 is provided on these tie bar screw nuts 13.

The toggle link mechanism 5 is provided with a crosshead 3, and the toggle link mechanism 5 is adapted to bend and extend in the axial direction by moving the crosshead 3 in the axial direction. The crosshead 3 is provided with a ball screw nut 14, and one end portion of the ball screw shaft 2 on which the threaded portion is formed is the ball screw nut 14.
It is screwed to. The ball screw shaft 2 extends in a certain direction along the axial direction, penetrates the end housing 18, and is rotatably supported by a support member 26 provided on the end housing 18. A driven pulley 6 is provided at the other end of the ball screw shaft 2. The driven pulley 6 is connected to the drive pulley 8 of the servomotor 1 via a belt 7. When the servomotor 1 is driven to rotate the drive pulley 8, the driven pulley 6 rotates via the belt 7, The ball screw shaft 2 is thereby rotated.

As shown in FIG. 2, a driving gear 10 and four driven gears 12 provided on the mold thickness adjusting motor 9 are provided.
Respectively mesh with the interlocking gear 11. Therefore, when the mold thickness adjusting motor 9 is driven and the drive gear 10 is rotated, the interlocking gear 11 is rotated, and accordingly, the four driven gears 12 are rotated by the same rotation amount.

Next, the operation of the toggle type mold clamping device described above will be described.

First, the crosshead 3 is retracted toward the end housing 18 to a predetermined position so that the toggle link mechanism 5 has a predetermined mold clamping stroke. Specifically, the servo motor 1 is driven to rotate the drive pulley 8, and the driving force thereof is transmitted to the ball screw nut 14 via the belt 7, the driven pulley 6, and the ball screw shaft 2, and the cross head 3 is moved. Move to the left in the figure to a predetermined position. At this time, the positioning of the crosshead 3 is performed by feedback control based on the rotation amount of the servo motor 1 and the detection result of the position sensor 19.

Subsequently, the mold clamping mechanism 4, 5, 18 including the structure from the end housing 18 to the movable platen 4 is fixed to the fixed platen 21.
In a direction (to the right in the drawing), the movable side mold 22b provided on the movable platen 4 is brought into contact with the fixed side mold 22a provided on the fixed platen 21. In the following, the mold 22
The contact between a and 22b is called "touch".

Specifically, in this mold touch, the mold thickness adjusting motor 9 is driven to rotate the driving gear 10, and the driving force is transmitted from the interlocking gear 11 to each driven gear 12 so that each tie bar screw nut. 13 to rotate the mold clamping mechanism 4,
This is done by moving 5,18. The mold thickness adjusting motor 9 is controlled to be driven until it is confirmed that the movable mold 22b has touched the fixed mold 22a, and to stop when the touch is confirmed.

Conventionally, a speed detecting device 23 connected to the position sensor 20 as shown in FIG. 4 has been used as a means for confirming that the die has touched. The speed detecting device 23 detects whether or not the moving speed of the mold clamping mechanisms 4, 5, 18 has reached the moving speed preset by the setter 25. When a pressing force is applied between the molds 22a and 22b, the moving speed of the mold clamping mechanisms 4, 5, and 18 decreases. Therefore, the speed detecting device 23 is configured to stop the mold thickness adjusting motor 9 when detecting that the moving speed of the mold clamping mechanism has decreased to the moving speed preset by the setter 25. Therefore, when the mold thickness adjusting motor 9 is stopped, the movable side mold 22b is fixed to the fixed side mold 22.
It is brought into contact with a with a predetermined pressing force.

Next, the servo motor 1 is driven from the state where the molds 22a and 22b are touched with each other in this way,
This time, the ball screw shaft 2 is rotated in the direction in which the distance between the end housing 18 and the crosshead 3 is widened, and finally the toggle link mechanism 5 is fully extended. During this time, the fixed-side mold 22a and the movable-side mold 22b are in contact with each other, the movable platen 4 is not moved, and the extension of the toggle link mechanism 5 in the axial direction is that the end housing 18 retracts to the left in the drawing. Absorbed by. End housing 18
Since the tie bar screw nuts 13 are kept from rotating even when the end housings 18 are retracted, the four tie bars 15 are extended by the amount by which the end housings 18 are retracted. As a result, the reaction force associated with the extension is applied between the two molds 22a and 22b, and the molds 22a and 22b are clamped.

As described above, in the molds 22a and 22b, the pressing force generated when the mold thickness adjusting motor 9 moves the mold clamping mechanisms 4, 5 and 18 to make the molds 22a and 22b touch each other, and thereafter, The mold is clamped by the mold clamping force which is the total of the reaction force of the tie bar 15 obtained by extending the toggle link mechanism 5. Therefore, in order to obtain a predetermined mold clamping force, it is necessary to first touch the molds 22a and 22b with a predetermined pressing force.

[0015]

However, the rotational sliding resistance between the tie bar screw nut 13 for moving the mold clamping mechanisms 4, 5, and 18 and the tie bar screw 16, and the bed 17 are not provided.
The sliding resistance of the movable platen 4 and the end housing 18 with respect to changes with time. When the sliding resistance in each part changes in this way, the speed detecting device 23 detects that the moving speed of the mold clamping mechanisms 4, 5, and 18 has decreased to the moving speed preset by the setter 25, and the mold thickness is detected. Even when the adjustment motor 9 is stopped, the pressing force actually applied to the molds 22a and 22b is changed by the change in the sliding resistance force of each part.

In this way, the molds 22a, 22a,
In the configuration for confirming the touch between the two 22b, the rotary sliding resistance between the tie bar screw nut 13 and the tie bar screw 16 and the movable platen 4 and the end housing 1 with respect to the bed 17 are used.
When the sliding resistance, such as the sliding resistance of No. 8, which may occur when the mold clamping mechanisms 4, 5, 18 are moved by the mold thickness adjusting motor 9, changes with time, the molds 22a, 22b are separated from each other accordingly. There is a problem in that the applied pressing force also changes.

Therefore, according to the present invention, even if the sliding resistance that can occur when the mold clamping mechanism is moved by the mold thickness adjusting motor changes with time, the pressing force applied to the molds does not change. It is therefore an object of the present invention to provide a method for adjusting a mold pressing force of a toggle type mold clamping device and a toggle type mold clamping device that can obtain a predetermined mold clamping force.

[0018]

In order to achieve the above object, a method for adjusting a mold pressing force of a toggle type mold clamping device according to the present invention is a fixed plate fixed on a bed and a fixed side mold is attached. A mold including a movable plate and a movable plate movable on the bed, and an end housing connected to the movable plate via a toggle link mechanism and movable on the bed. A clamping mechanism, and the mold clamping mechanism is configured to be moved by a mold thickness adjusting motor in a direction toward and away from the fixed plate, and the toggle link mechanism is configured by a servo motor to the end housing. A fixed-side mold and a front part of a toggle-type mold clamping device configured to bend and extend with the movement of a crosshead that is moved toward and away from Adjusting the pressing force generated in the mold with each other when the movable die is touch one another,
In a method for adjusting a mold pressing force of a toggle type mold clamping device, the mold thickness adjusting motor is driven to move the mold clamping mechanism in a direction approaching the fixed plate, and the fixed side mold and the movable side mold are In the process of touching each other, the cross head is pressed in the direction approaching the end housing by the reaction force of the pressing force generated between the molds, thereby resisting the torque applied to the servo motor, The servomotor is driven so as to maintain the crosshead at a predetermined position with respect to the end housing, and it is detected whether or not the torque generated by the servomotor against the torque has reached a predetermined value. The mold thickness adjusting motor is stopped when it is detected that the predetermined value has been reached.

In the toggle type mold clamping device of the present invention, a fixed plate fixed to a bed and having a fixed side mold attached thereto and a movable side mold are attached so that the movable mold can be moved on the bed. A movable platen, and a mold clamping mechanism including an end housing that is connected to the movable platen via a toggle link mechanism and is also movable on the bed. The cross link is configured to be moved in a direction close to and away from the fixed plate, and the toggle link mechanism is moved by a servomotor in a direction close to and away from the end housing. In the toggle type mold clamping device configured to bend and stretch with
The servo motor drives the mold thickness adjusting motor to move the mold clamping mechanism in a direction closer to the fixed platen, and the fixed side mold and the movable side mold are in contact with each other, The cross head is pressed against the torque applied to the servo motor by the reaction force of the pressing force generated between the molds in the direction approaching the end housing, and the cross head is moved toward the end housing in a predetermined direction. The servo motor is configured to be driven so as to be maintained at a position, detects whether the torque generated by the servo motor against the torque has reached a predetermined value, and reaches the predetermined value. A torque detecting device for stopping the mold thickness adjusting motor when it is detected is provided.

According to the present invention, the pressing force generated when the molds are touched with each other is directly detected as the value of the torque applied to the servo motor. Therefore, the pressing force applied to the molds at the time of touching the molds can be stably adjusted with time without being affected by the change with time of the sliding resistance that may occur when the mold clamping mechanism is moved. . Therefore, it is possible to stabilize the mold clamping force between the molds that have been finally clamped, so that a molded product can be manufactured stably, and the mold clamping force becomes excessive and the mold clamping device It is possible to eliminate the risk of damaging the mold.

Further, in the toggle type mold clamping device of the present invention, the crosshead is provided with a ball screw nut to which a screw portion formed on a ball screw shaft rotatably driven by the servo motor is screwed. The ball screw nut rotates the ball screw shaft when the cross head is pressed toward the end housing by the reaction force of the pressing force generated between the molds. It may be configured to occur by acting to cause.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram for explaining an embodiment of the toggle type mold clamping device of the present invention.

In the present embodiment, a torque detecting device 24 is used in place of the speed detecting device 23 (see FIG. 4) used conventionally. This torque detection device 24 is composed of the molds 22a, 2
The pressing force generated when 2b is touched is detected as the value of the torque exerted on the servomotor 1, and when it is detected that the torque value has reached a predetermined value preset by the setter 25, It is configured to stop the thickness adjusting motor 9.

Since the mold pressing force adjusting method of this embodiment is also applied to the toggle type mold clamping device described with reference to FIGS. 1 and 2, the toggle type mold clamping device is also applicable to this embodiment. This will be described with reference to FIGS. 1 and 2. However, in this embodiment, a detailed description of the toggle type mold clamping device is omitted.

Next, the operation of the toggle type mold clamping device of this embodiment will be described.

First, the crosshead 3 is retracted toward the end housing 18 to a predetermined position so that the toggle link mechanism 5 has a predetermined mold clamping stroke. Specifically, the servo motor 1 is driven to rotate the drive pulley 8, and the driving force thereof is transmitted to the ball screw nut 14 via the belt 7, the driven pulley 6, and the ball screw shaft 2, and the cross head 3 is moved. Move to the left in the figure to a predetermined position. At this time, the positioning of the crosshead 3 is performed by feedback control based on the rotation amount of the servo motor 1 and the detection result of the position sensor 19.

Subsequently, the mold clamping mechanism 4 including the structure from the end housing 18 of the toggle type mold clamping device to the movable platen 4.
5 and 18 are moved in the direction approaching the fixed platen 21 (rightward in the drawing), and the movable mold 22b provided on the movable platen 4 is touched on the fixed mold 22a provided on the fixed platen 21.
Specifically, in this mold touch, the mold thickness adjusting motor 9 is driven to rotate the driving gear 10, the driving force is transmitted from the interlocking gear 11 to each driven gear 12, and each tie bar screw nut 13 is rotated. Then, the mold clamping mechanisms 4, 5, 18 are moved. The mold thickness adjusting motor 9 is controlled to be driven until it is confirmed that the movable mold 22b has touched the fixed mold 22a, and to stop when the touch is confirmed.

At this time, a pressing force is generated between the molds 22a and 22b, and the reaction force of the pressing force acts on the crosshead 3 from the movable plate 4 via the toggle link mechanism 5. This reaction force causes the crosshead 3 to move the end housing 1
8 in the direction of the ball screw nut 14
Generates a torque that rotates the ball screw shaft 2. This torque is applied to the driven pulley 6, the belt 7, and the drive pulley 8.
To try to rotate the servo motor 1.

When the servomotor 1 is rotated by this force, the crosshead 3 is further retracted toward the end housing 18 side from a predetermined position, and the pressing force between the molds 22a and 22b is reduced. Therefore, the end housing 1
In order to maintain the position of the crosshead 3 with respect to 8 at the above predetermined position, the positioning control of the crosshead 3 is performed by feedback control based on the rotation amount of the servomotor 1 and the detection result of the position sensor 19.
Generates a driving torque sufficient to withstand this force. When the torque detection device 24 detects that the torque generated by the servo motor 1 has reached the torque preset by the setter 25, the torque detection device 24 stops the mold thickness adjustment motor 9.

The set value of this torque is set in the molds 22a, 22
It is determined by previously knowing the correlation between the pressing force (reaction force) generated between b and the torque value applied to the servo motor 1. Therefore, by detecting that the value of the drive torque generated in the servomotor 1 has reached a predetermined torque value by the torque detection device 24, a predetermined pressing force is applied between the molds 22a and 22b. Can be confirmed.

The torque detection device 24 in this embodiment
In this way, the pressing force generated when the molds 22a and 22b are touched with each other is directly detected as the value of the torque applied to the servomotor 1.

Next, the servo motor 1 is driven from the state where the molds 22a and 22b are touched in this manner,
This time, the ball screw shaft 2 is rotated in the direction in which the distance between the end housing 18 and the crosshead 3 is widened, and finally the toggle link mechanism 5 is fully extended.
The reaction force associated with the extension of the four tie bars 15 is
22b, and the molds 22a and 22b are finally clamped.

As described above, in this embodiment, the mold 22 is used.
Since the pressing force (reaction force) generated between a and 22b is directly detected as the torque value applied to the servo motor 1 via the cross head 3 and the ball screw shaft 2, it is configured as in the prior art. In addition, the pressing force applied to the dies 22a and 22b at the time of touching the dies is not affected by the change with time of the sliding resistance that may occur when the die clamping mechanisms 4, 5 and 18 are moved by the die thickness adjusting motor 9. The pressure can be adjusted stably over time. Therefore, since the mold clamping force between the molds 22a and 22b finally clamped can be stabilized, a molded product can be manufactured in a stable manner, and the mold clamping force becomes too large. Tightening device 4,
It is possible to eliminate the risk of damaging the molds 5, 18 and the molds 22a, 22b.

[0035]

As described above, according to the present invention, the mold thickness adjusting motor is driven to move the mold clamping mechanism in the direction of approaching the stationary platen so that the stationary mold and the movable mold touch each other. During the process of pressing, the crosshead is pressed toward the end housing by the reaction force of the pressing force generated between the molds and resists the torque applied to the servomotor, and the crosshead is positioned at a predetermined position with respect to the end housing. The servo motor is driven so as to maintain the torque, and it is detected whether or not the torque generated by the servo motor against the torque reaches a predetermined value, and when it is detected that the predetermined value is reached. Since it is configured to stop the mold thickness adjusting motor, even if the sliding resistance that can occur when moving the mold clamping mechanism by the mold thickness adjusting motor changes over time, Erareru pressing force is not changed, it is possible to turn obtaining a predetermined mold clamping force.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a general toggle-type mold clamping device with a part thereof broken.

2 is a view of the toggle type mold clamping device shown in FIG. 1 as seen from the direction of arrow A in FIG.

FIG. 3 is a configuration diagram for explaining an embodiment of a toggle type mold clamping device of the present invention.

FIG. 4 is a diagram for explaining a method of adjusting a mold pressing force of a conventional toggle type mold clamping device.

[Explanation of symbols] 1 Servo motor 2 ball screw shaft 3 crosshead 4 movable plate 5 Toggle link mechanism 6 Driven pulley 7 belt 8 drive pulley 9 type thickness adjustment motor 10 drive gear 11 interlocking gear 12 Driven gear 13 Tie bar screw nut 14 Ball screw nut 15 Thai bar 16 tie bar screw 17 beds 18 End housing 19,20 Position sensor 21 Fixed platen 22a Fixed side mold 22b Movable mold 23 Speed detector 24 Torque detector 25 Setting device 26 Support members

Claims (3)

[Claims] 1. A fixed platen (21) fixed to a bed (17) and having a fixed side mold (22a) attached thereto, and a movable side mold (22b) are attached to the bed (17). ) A movable platen (4) movable above, and an end housing (18) connected to the movable platen (4) via a toggle link mechanism (5) and also movable above the bed (17). And a mold clamping mechanism (4, 5, 18) including the mold clamping mechanism (4,5, 18).
The toggle link mechanism (5) is configured to be moved toward and away from the fixed platen (21) by a servomotor (1) by the servomotor (1). (3) which is moved in the direction of moving and in the direction of moving apart
Of the toggle type mold clamping device configured to bend and stretch with the movement of the mold (22a) when the fixed mold (22a) and the movable mold (22b) are touched with each other. , 22b) for adjusting the pressing force generated between the two, the method for adjusting the pressing force of the mold of the toggle type clamping device, wherein the mold thickness adjusting motor (9) is driven to drive the mold clamping mechanism (4, 5, 18). During the process in which the fixed side mold (22a) and the movable side mold (22b) are brought into contact with each other while being moved toward the fixed plate (21), the molds (22a, 22b) are moved to each other. The crosshead (3) moves the end housing (1) by the reaction force of the pressing force generated.
8) is pushed toward the servomotor (1) to resist the torque applied to the servomotor (1), and the servo is maintained to maintain the crosshead (3) at a predetermined position with respect to the end housing (18). When the motor (1) is driven to detect whether the torque generated by the servo motor (1) against the torque has reached a predetermined value, and when it has been detected that the predetermined value has been reached. A method for adjusting mold pressing force of a toggle type mold clamping device, characterized in that the mold thickness adjusting motor (9) is stopped. 2. A fixed platen (21) fixed on a bed (17), to which a fixed side mold (22a) is attached, and a movable side mold (22b) are attached. ) A movable platen (4) movable above, and an end housing (18) connected to the movable platen (4) via a toggle link mechanism (5) and also movable above the bed (17). And a mold clamping mechanism (4, 5, 18) including the mold clamping mechanism (4,5, 18).
The toggle link mechanism (5) is configured to be moved toward and away from the fixed platen (21) by a servomotor (1) by the servomotor (1). (3) which is moved in the direction of moving and in the direction of moving apart
In the toggle type mold clamping device configured to bend and stretch with the movement of the mold, the servo motor (1) is the mold thickness adjusting motor (9).
To move the mold clamping mechanism (4, 5, 18) toward the fixed platen (21), and the fixed side mold (22a) and the movable side mold (22b) are touched with each other. The cross head (3) is generated by the reaction force of the pressing force generated between the molds (22a, 22b) during the process of
Is pressed toward the end housing (18) to resist the torque applied to the servomotor (1) and maintain the crosshead (3) in a predetermined position with respect to the end housing (18). The servo motor (1) detects whether or not the torque generated against the torque has reached a predetermined value, and reaches the predetermined value. A toggle type mold clamping device, characterized in that a torque detection device (24) for stopping the mold thickness adjusting motor (9) when it is detected is provided. 3. The crosshead (3) is provided with a ball screw nut (14) to which a screw portion formed on a ball screw shaft (2) rotated by the servomotor (1) is screwed. The torque applied to the servo motor (1) is generated by the cross head (3) by the reaction force of the pressing force generated between the molds (22a, 22b).
The ball screw nut (14) is configured to be caused by acting to rotate the ball screw shaft (2) by being pressed in a direction approaching 8).
The toggle type mold clamping device described in.