JPH06182599A - Press controller - Google Patents

Abstract

PURPOSE:To restrain the fluctuation of impact force of a ram to a work and to improve machining accuracy by gradually reducing the speed of the ram between the position of deceleration point and a certain distance before the set position of the bottom dead center. CONSTITUTION:When the ram 13 reaches a certain distance before the set point of the bottom dead center in the process of the movement from the top dead center to the bottom dead center, the ram 13 is controlled so as to be lowered at a constant speed. After the ram 13 is lowered at high speed from the top dead center to the position of deceleration point by driving a servo motor 6, the ram 13 is gradually reduced its speed between the position of deceleration point and a certain distance before the set position of the bottom dead center with a controlling part 19. Next, after the ram is pressed against the work till it is stopped, the ram 13 is lowered a certain fixed speed. In this way, the upper die 20 of the ram 13 is pressed against the work by a stable impact force in spite of the variation of the work and, as a result, machining accuracy is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press control device for converting a rotary motion of a servo motor into a linear motion to drive a ram, and more particularly to a press control device suitable for machining an extremely thin product into a desired shape.

[0002]

2. Description of the Related Art Conventionally, in a press control device for converting a rotary motion of a servo motor into a linear motion to drive a ram, during machining, the ram moves at a high speed from a top dead center to a deceleration point position, After that, the ram decelerates gradually from the deceleration point position,
It is configured to hit the workpiece and stop at the bottom dead center setting position. In that case, when the ram decelerates, the rams are stopped by the stoppers of the molds hitting each other. Alternatively, in a press control device that does not have a stopper, the ram decelerates gradually from the deceleration point position, and the upper die of the ram sandwiches the workpiece with the lower die, so that the ram is lowered under pressure. Some are configured to stop at the dead center setting position. The bottom dead center setting position is set by moving the ram in advance during actual machining. That is, the bottom dead center setting position is determined by lowering the ram at a constant speed to stop the ram, and reading the stopped position by the encoder of the servo motor. In addition,
A device related to this type of device is, for example, JP-A-64
-34518 publication etc. are mentioned.

[0003]

By the way, the above-mentioned press control device of the prior art is designed to process the work piece by gradually lowering the ram, but at the time when the ram hits the work piece, the servo motor control is performed. The deceleration speed of the ram is unstable because it is a transitional time from the deceleration of the system toward the bottom dead center setting position. Further, since the thickness of the workpiece varies, the position where the upper die of the ram hits the workpiece changes, and the impact force on the workpiece changes. That is, if the thickness of the work piece is thick, the upper die of the ram hits the work piece at a time when the deceleration is as fast as that, so the impact force on the work piece becomes large, and conversely if the work piece is thin, Since the upper die of the ram hits the workpiece during the slow deceleration, the impact force on the workpiece becomes small. Therefore, not only the deceleration speed of the ram becomes unstable, but also the impact force of the ram on the workpiece fluctuates due to the variation in the thickness of the workpiece, so that there is a problem that the machining accuracy decreases. In order to solve the above problem, the following can be easily considered. That is, in order to reliably process the work piece having the thinnest thickness, it is easy to consider that the stroke of the ram is lengthened and the deceleration point position a is slightly lowered to a ', as shown by the chain line in FIG. To be
However, in doing so, when a thick workpiece is processed, the impact speed of the ram against the workpiece becomes such a high time, so that in the case of a thick workpiece, the impact force of the ram against the workpiece is b. There is a problem that the desired shape cannot be formed as a result of moving from the point to the point b ′ and becoming significantly larger accordingly. When setting the bottom dead center position to determine the bottom dead center setting position, the ram descends at a constant speed and is stopped.Therefore, the ram bottom dead center position setting speed and the actual machining speed are Differently, therefore, the magnitude of the impact force at the time of setting the bottom dead center position and the magnitude of the impact force at the time of processing are different, which causes a problem of lowering the reliability of the bottom dead center position setting. Furthermore, when the data of the bottom dead center setting position is obtained by the bottom dead center position setting operation, and the ram is driven based on the obtained bottom dead center setting position to machine, the amount of movement of the ram to obtain the abutting pressure is reduced. However, not only the thickness variation of the work piece but also the rigidity and vibration of the press itself may cause it to become larger or smaller. Therefore, the pressing force against the work piece is not stable. This will cause the accuracy to drop further. In particular, a workpiece having a thickness of about 0.01 mm has a problem that the processed shape becomes excessive or insufficient if the movement amount of the ram slightly changes.

In view of the above circumstances, an object of the present invention is to provide a press control device capable of suppressing the fluctuation of the impact force of the ram on the workpiece and improving the machining accuracy.

[0005]

In the press controller of the present invention, when the ram is moved from the top dead center to the bottom dead center setting position by the control unit, the deceleration point position and the constant distance from the bottom dead center setting position. It has means for gradually decelerating the ram up to the front distance and moving the ram at a specific constant speed from the front distance to the bottom dead center setting position.

[0006]

[Operation] When the ram descends from the top dead center to the bottom dead center setting position to actually machine the workpiece, it descends at high speed from the top dead center to the deceleration position, but from the deceleration position to the bottom dead center. The ram gradually descends toward the position while decelerating, and at a certain distance before the bottom dead center setting position, the ram decelerates to a certain constant speed and stops the workpiece, so
The impact force of the upper die of the ram against the work piece is stable, and there is no need to be concerned with variations in the thickness of the work piece. Therefore, the upper die of the ram can press against the work piece with a stable impact force regardless of the variation of the work piece, so that the working accuracy can be improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The press control device according to the embodiment bends an extremely thin lead provided in an IC, and as shown in FIG. 1, an upper base 3 is mounted on a lower base 1 via a column 2. A mounting plate 5 is mounted on the upper base 3 via a cylindrical guide 4. A servo motor 6 is installed at the right end of the mounting plate 5 with the output shaft 7 facing upward, and a pulley 8 is mounted on the output shaft 7 of the servo motor 6 and a gap between the pulley 8 and the other pulley 10 is provided. A timing belt 9 is wound around. The pulley 10 is mounted on the ball screw 11. The ball screw 11 has an upper portion formed so that the pulley 10 can be attached thereto, and an intermediate position formed so as to be inserted into the mounting plate 5 via a bearing or the like.
A threaded portion (not shown) is formed on the outer periphery of the lower portion located inside the lower portion, and the lower threaded portion is engaged with a ball screw nut 12 arranged inside the guide 4 so as to be rotatable about an axis. . A ram 13 is provided around the ball screw nut 12.
Is fixed, and the ram 13 is attached to the inner circumference of the guide 4 so as to be slidable in the axial direction. Therefore, when the servomotor 6 is driven, the ball screw 11 rotates around the shaft via the pulley 8, the timing belt 9, and the pulley 10, and the rotation of the ball screw 11 causes the ball screw nut 12 to rotate.
And the ram 13 integrally move linearly in the axial direction. Therefore, the ram 13 is connected to the output shaft 7 of the servomotor 6 and the pulley 8
10 are connected via a power conversion mechanism including a timing belt 9, a ball screw 11, and a ball screw nut 12. A rotation stopper plate 14 is fitted and fixed to a lower end portion of the ram 13 which projects outward from the guide 4, and a guide shaft 15 is attached to the rotation stopper plate 14. The lower portion of the guide shaft 14 is fixed to the above-described rotation preventing plate 14, and the intermediate position thereof is inserted through the holes 16 provided in the flange portions of the upper base 3 and the guide 4. Therefore, when the ram 13 is moved in the axial direction by the drive of the servo motor 6, the anti-rotation plate 14 is also moved accordingly. At that time, the guide shaft 15 is guided by the guide 4 and the hole 16 of the upper base 3. This prevents the ram 13 from rotating around its axis. Further, a shank holder 17 is attached to the lower end of the ram 13, and the upper die 20 of the press is fixed to the shank holder 17. Below the upper mold 20, the lower mold 21 of the press installed on the lower base 1 is arranged, and when the ram 13 descends,
Along with that, the upper mold 20 is guided by the guide post 22 and moves toward the lower mold 22. In this case, the servo motor 6 descends from the top dead center to the deceleration point position at high speed when the ram 13 moves from the top dead center to the bottom dead center, and decelerates from there when the ram 13 reaches the deceleration point position. Thus, the processed product is formed into a desired shape. Therefore, this press control device uses the servo motor 6 to move the ram 13 at a moving speed, so that the workpiece can be formed into a desired shape.
Control unit 19 for controlling the amount of movement, top dead center, deceleration point position, etc.
And an operation panel 1 for programming those control contents
8 and. Then, the press control device preliminarily processes the ram 1 at a specific constant speed v when actually processing the work.
The position of the bottom dead center is determined by lowering 3 and performing a so-called bottom dead center position setting operation, and this position is set as the bottom dead center setting position S1.

In the press control apparatus of the embodiment, when the control section 19 actually processes the workpiece, the ram 13 is moved from the top dead center to the bottom dead center setting position S1 through the stroke S while the ram 13 moves downward. When the distance β before the constant distance is reached from the dead point setting position S1, the ram 1 is moved at a constant speed.
3 is controlled to descend. Specifically, as shown in FIG. 2, when the ram 13 descends from the top dead center to the deceleration point position a at a high speed by the driving of the servomotor 6, the ram 13 then moves to the deceleration point position a. , Between the bottom dead center setting position S1 and the distance β before the constant distance, the speed is gradually reduced, and when the distance β before the constant distance is reached,
The ram 13 is further lowered at a constant speed v until the workpiece is pressed and stopped. In this case, the distance β, which is a predetermined distance before the bottom dead center setting position S1, takes into consideration variations in the thickness of the workpiece, variations in the press machine and the die, and the ram 13 moves at a constant velocity v with respect to the workpiece. It is preferable to set the distance as short as possible in order to shorten the cycle time of press working as well as the distance that can be surely hit and stopped at the bottom dead center position setting operation in this example. The same speed as the specific constant speed v in. Further, this distance β is configured to be automatically calculated by the control unit 19 when the bottom dead center setting position S1 is input by the bottom dead center position setting operation when the workpiece is actually processed. See also Ram 13
When the workpiece is pressed into a desired shape and is processed into a desired shape, the workpiece can be pressed within a desired pressing force range regardless of variations in the workpiece. A constant distance α is provided in the forward direction of the ram. This distance α is the same as the above-mentioned distance β in order to save the operation labor, and the bottom dead center setting position S is set by the bottom dead center position setting operation.
When 1 is input, the control unit 1
9 is automatically calculated.

The press control device of the embodiment is as described above.
Servo motor 6 for ram 13 to actually process the workpiece
When descending from the top dead center to the bottom dead center setting position S1 by driving the vehicle, it descends at a high speed from the top dead center to the deceleration point position a, but from the deceleration point position a to the bottom dead center setting position S1, the ram 13 gradually descends while decelerating, and at a distance β which is a certain distance before the bottom dead center setting position S1, the workpiece 13 is decelerated to a certain constant speed v and the workpiece is pressed and stopped. The impact force of the mold 20 is stable, and there is no need to be concerned with variations in the thickness of the workpiece. Therefore, the upper die 20 of the ram 13 can be pressed against the work piece with a stable impact force regardless of the variation of the work piece, so that the working accuracy can be improved. Further, since the constant velocity v is the same as the constant velocity v at the time of the bottom dead center position setting operation, the impact force at the time of setting the bottom dead center position and the impact force at the time of machining are actually processed. Is the same, and there is no difference in the magnitude of the impact force of both sides as in the conventional technology,
The significance of the speed at which the bottom dead center position setting operation is performed becomes effective, and the reliability of the bottom dead center position setting is enhanced. In addition, Ram 1
Since the upper die 20 of 3 moves a predetermined distance α from the bottom dead center setting position S1, even if the work has a dimension thinner than the predetermined one by ΔS2, the work is surely pressed and stopped. Not only is it possible to obtain a predetermined pressing force by continuing to press the workpiece, but it is possible to reliably form the desired shape. That workpiece becomes the actual bottom dead center position minus [Delta] S ₁ from the bottom dead center set positions S1 as shown in FIG. 2 when [Delta] S ₁ thin,
The workpiece is the position plus [Delta] S ₂ at the bottom dead point setting position S1 as shown in the figure becomes the actual bottom dead center when [Delta] S ₂ thick, upper metallic any case the position at that time Since the mold 20 is at the position where the workpiece is continuously pressed and stopped at a constant speed v, it is not necessary to be concerned with variations in the thickness of the workpiece. Therefore, the upper die 20 of the ram 13 can press against the work piece with a stable impact force regardless of the variation of the work piece, so that the working accuracy can be further improved. In the illustrated embodiment, an example of bending is shown as forming of the workpiece, but it is needless to say that the same effect can be obtained by applying it to punching.

[0010]

As described above, according to the first aspect of the present invention, when the ram descends, the ram decelerates to a constant speed at a distance before the bottom dead center setting position by a constant distance to move the workpiece. Since it is configured to stop pressing, the upper die of the ram can press against the work piece with a stable impact force regardless of the work piece variation, and as a result, it is possible to improve the processing accuracy. is there. According to claim 2, the ram is moved at the same speed as the specific constant speed at the time of the bottom dead center position setting operation between the distance before the constant distance and the bottom dead center setting position. Even when machining, the impact force at the time of setting the bottom dead center position and the impact force during machining are the same. As a result of not occurring, the significance of the speed at which the bottom dead center position setting operation is performed becomes effective, the reliability of the bottom dead center position setting increases, and according to claim 3, the pressing force of the ram on the workpiece fluctuates. Since it is configured to move the ram a certain distance from the bottom dead center setting position within the range not to do so and to reliably shape it into a desired shape, it is possible to press with a stable impact force regardless of the variation of the work piece, In addition to the effect of claim 2, processing The effect of called degree of can be further improved.

[Brief description of drawings]

FIG. 1 is an overall partially broken view showing a press control device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of a ram controlled by a control unit.

FIG. 3 is an explanatory diagram of the operation of a ram showing an example of a conventional press control device.

[Explanation of symbols]

6 ... Servo motor, 13 ... Ram, 20 ... Upper mold, 21 ...
Lower die, a ... deceleration point position, S ... bottom dead center setting position, β ... distance before bottom dead center setting position, a ... constant distance,
v ... a certain constant speed.

Claims (3)

[Claims] 1. A servo motor, a ram that is connected to an output shaft of the servo motor through a power conversion mechanism, and linearly reciprocates, and a control unit that controls a moving speed and a moving amount of the ram via the servo motor. The bottom dead center setting position is determined by moving the ram at a specific constant speed during the bottom dead center position setting operation.
In the press control device configured to move the ram at high speed from the top dead center to the deceleration point position at the time of actual processing of the work, and to decelerate between the deceleration point position and the bottom dead center setting position, the control unit includes: Is moving from top dead center to bottom dead center setting position,
A means for gradually decelerating the ram between the deceleration point position and the distance from the bottom dead center setting position to a distance before the fixed distance, and moving the ram at a constant speed from the distance before the fixed distance to the bottom dead center setting position. A press control device characterized by having. 2. A servo motor, a ram which is connected to an output shaft of the servo motor through a power conversion mechanism and which linearly reciprocates, and a control unit which controls a moving speed and a moving amount of the ram via the servo motor. The bottom dead center setting position is determined by moving the ram at a specific constant speed during the bottom dead center position setting operation.
In the press control device configured to move the ram at high speed from the top dead center to the deceleration point position at the time of actual processing of the work, and to decelerate between the deceleration point position and the bottom dead center setting position, the control unit includes: Is moving from top dead center to bottom dead center setting position,
While gradually decelerating the ram between the deceleration point position and the distance from the bottom dead center setting position to a certain distance before, the bottom dead center position is set between the certain distance before and the bottom dead center setting position. A press control device comprising means for moving a ram at the same speed as the specific constant speed during operation. 3. A servo motor, a ram which is connected to an output shaft of the servo motor via a power conversion mechanism and linearly reciprocates, and a control unit which controls a moving speed and a moving amount of the ram via the servo motor. The bottom dead center setting position is determined by moving the ram at a specific constant speed during the bottom dead center position setting operation.
In the press control device configured to move the ram at high speed from the top dead center to the deceleration point position at the time of actual processing of the work, and to decelerate between the deceleration point position and the bottom dead center setting position, the control unit includes: Is moving from top dead center to bottom dead center setting position,
While gradually decelerating the ram between the deceleration point position and the distance from the bottom dead center setting position to a certain distance before, the bottom dead center position is set between the certain distance before and the bottom dead center setting position. A means for moving the ram at the same speed as the specific constant speed during operation, and means for moving the ram by a predetermined distance from the bottom dead center setting position within a range in which the pressure of the ram against the workpiece does not change. Characteristic press control device.