JP2000015339A - Method for controlling stop of ram in press brake and device for controlling stop thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the development of troubles, such as synchronous deviation and the breakage of a die by calculating a stopping distance from the shifting speed and the decelerating time of a driving shaft and a new target stopping position while using the stopping distance and controlling so as to stop all driving shafts. SOLUTION: Upper dies are supported with rams having plural driving shafts. Lower dies are disposed so as to be faced to the upper dies and a sheet material is bent with these dies. Then, at the time of transmitting the stopping command during performing the synchronous control for shifting the ram by synchronizing each driving shaft, the shifting speed V of the driving shaft to the ram at this timing and the stopping distance from the decelerating time, with which the shifting speed becomes zero, are calculated. The new target stopping position is calculated by adding or decreasing the stopping distance obtd. with this to a stopping signal transmitting position. Each driving shaft is controlled so as to stop all the driving shafts to the new target stopping position. In this way, all the driving shafts can be stopped to the same position while holding the rams to the horizontal state without developing the deformation of the ram.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the cooperation of an upper mold supported by a ram having a plurality of drive shafts and a lower mold supported by a fixed table so as to face the upper mold. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ram stop control method and a stop control device for a press brake that bends a plate by operation.

[0002]

2. Description of the Related Art Generally, in a press brake, a ram and a fixed table are opposed to each other, an upper die (punch) is provided at a lower end of the ram, and a lower die (die) is provided at an upper part of the fixed table. A plat is inserted between the upper mold and the lower mold, and the ram is operated by a hydraulic cylinder or an AC servomotor. The work is pressed and bent to a required bending angle.

In this type of press brake, when correcting the deflection of the ram and the fixed table,
2. Description of the Related Art A wedge device or a deflection correction device is attached to a machine body to set correction crowning. However, in the method using the wedge device or the like, there are problems that the device itself becomes complicated or adjustment of the correction of the bending becomes difficult.

[0004] In order to deal with such a problem, the present applicant has filed the invention of the prior application (Japanese Patent Application No. 9-159399).
No.), a synchronous control execution area for synchronously moving a plurality of drive shafts attached to a ram and an independent control execution area for independently moving each drive axis are combined,
A ram control method of a press brake has already been proposed in which synchronous control start / end positions for each drive shaft are calculated and the drive shafts are controlled. According to this proposed ram control method, it is possible to easily and accurately correct the deflection of the plate material without using a special device such as a wedge device.

[0005]

However, when the ram drive is performed by combining the synchronous control of each drive shaft and the independent control as in the ram control method described in the prior invention, all the axes are synchronized. If the ram stop command is issued for some reason and each drive shaft stops during operation, and the stop position is different for each drive shaft, the ram is deformed. This causes the motor to stop, and starts moving without being kept horizontal when restarting. In the worst case, there is a problem that the ram or the mold is damaged.

The present invention has been made in view of such a problem, and in a press brake having a plurality of drive shafts, when a stop command is issued when all the drive shafts are driven by synchronous control. Provided is a ram stop control method and a stop control device for a press brake that can control each of the drive shafts to stop at the same stop position according to the moving speed so as not to cause a synchronization shift, a deformation of the ram, and the like. The purpose is to do so.

[0007]

In order to achieve the above-mentioned object, a method for controlling ram stop of a press brake according to a first aspect of the present invention includes an upper die supported by a ram having a plurality of drive shafts. A ram stop control method of a press brake for bending a plate material in cooperation with a lower mold supported by a fixed table so as to be opposed to the upper mold, wherein the ram is moved in synchronization with each drive shaft. When a stop command is issued during the execution of the synchronous control to be performed, the stop distance is calculated from the moving speed of the drive shaft with respect to the ram at the time of the generation of the stop command and the deceleration time until the moving speed becomes zero,
A new target stop position is calculated by adding or subtracting the obtained stop distance to or from the stop command generation position, and each drive shaft is controlled so as to stop all drive axes at the new target stop position. Things.

With this configuration, if a stop command is issued by, for example, turning off a foot switch or pressing a stop switch while the respective drive shafts are being moved synchronously, the stop command is issued. The stopping distance is obtained from the moving speed of the drive shaft with respect to the ram at the time when the occurrence of the stop occurs and the deceleration time until the moving speed becomes zero. Next, when the ram is lowered, the stop distance is subtracted from the stop command generation position, and when the ram is raised, the stop distance is added to the stop command generation position to obtain a new target stop position common to the drive shafts (the fixed table side). If the coordinate origin is set). Thereafter, each drive shaft is controlled to stop all the axes at the new target stop position. In this way, the ram can be stopped at the same position on all axes without deforming the ram while keeping the ram horizontal. Further, even when a restart command is issued, the drive shaft can be restarted without confirming the stop position of each drive shaft or checking the horizontal state of the ram.

In the present invention, the new target stop position is compared with a preset target stop position of each drive shaft, and when the set target stop position is closer to the new target stop position, the set target stop position is determined. Preferably, the control is performed such that all the drive shafts are stopped at the position, and when the new target stop position is before the set target stop position, all the drive shafts are stopped at the new target stop position. In this way, when the set target stop position, which is the original target stop position, is located before the new target stop position set based on the stop command, the motor is stopped at the set target stop position. Can avoid the occurrence of problems such as mold damage due to excessively passing the set target stop position.

Next, a ram stop control device for a press brake according to a second aspect of the present invention includes an upper die supported by a ram having a plurality of drive shafts, and a supporter mounted on a fixed table so as to face the upper die. A press brake ram stop control device that bends a plate material in cooperation with a lower mold that is
(A) When a stop command is issued during synchronous control for moving a ram by synchronizing the respective drive shafts, the moving speed of the drive shaft relative to the ram at the time of occurrence of the stop command and deceleration until the moving speed becomes zero. (B) a new target stop position for calculating a new target stop position by adding or subtracting the stop distance obtained by the stop distance calculation unit to or from the stop command generation position. And (c) control means for controlling each drive shaft so as to stop all drive shafts at the new target stop position calculated by the new target stop position calculation means.

The second invention relates to an apparatus for specifically realizing the press brake ram stop control method according to the first invention. In this second invention,
If a stop command is issued while each of the drive shafts is being moved synchronously, the stop distance calculating means sets the moving speed of the drive shaft relative to the ram at the time when the stop command is generated and the moving speed to zero. The stopping distance is calculated from the deceleration time until the time becomes. Next, the new target position calculating means subtracts the stop distance from the stop command generation position when the ram is lowered, and adds the stop distance to the stop command generation position when the ram is raised, so that a new target stop position common to each drive shaft is obtained. Calculation is performed (when the origin of the coordinate system is set on the fixed table side). Thereafter, the control means controls each drive shaft so as to stop all the axes at the new target stop position. Thus, similarly to the first invention, the ram can be stopped at the same position on all axes without deforming the ram while keeping the ram horizontal. Further, even when a restart command is issued, the drive shaft can be restarted without confirming the stop position of each drive shaft or checking the horizontal state of the ram.

In the present invention, there is further provided a comparing means for comparing the new target stop position with a preset target stop position of each drive shaft, wherein the control means controls the set target stop position by the comparing means. When it is determined that the target is located before the new target stop position, all drive shafts are stopped at the set target stop position. When it is determined that the new target stop position is located before the set target stop position, the new target is stopped. Preferably, control is performed so that all drive shafts are stopped at the stop position. By doing so, the new target stop position and the preset target stop position of each drive shaft are compared by the comparing means, and as a result of this comparison, the set target stop position, which is the original target stop position, is determined by the stop command. If the drive shaft is located before the new target stop position set based on the above, it will be stopped at the set target stop position, thereby avoiding the occurrence of problems such as mold damage due to each drive shaft going too far over the set target stop position. can do.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of a ram stop control method and a stop control device for a press brake according to the present invention will be described with reference to the drawings.

FIG. 1 is a front view of a press brake according to an embodiment of the present invention, FIG. 2 is a side view of the press brake, and FIG.
FIG. 2 is a control system configuration diagram of the press brake.

The press brake of this embodiment includes a fixed table 1 and a ram 2 driven up and down opposite to the fixed table 1, and the upper surface of the fixed table 1 is provided via a die holding device 3. A die (lower die) 4 having a V-shaped mold groove is held, and a punch (upper die) 5 is mounted below the ram 2 in opposition to the die 4 via a punch holding device 6. I have.

A pair of side frames 7 and 8 are integrally provided at both ends of the fixed table 1, and a support frame 9 is provided so as to connect upper ends of the side frames 7 and 8. A plurality of (four in this embodiment) ram drive devices 10a to 10d are attached to the support frame 9, and these ram drive devices 10a to 10d are mounted.
The ram 2 is connected to the lower end of d. Thus, the work W inserted between the punch 5 and the die 4 is bent by raising and lowering the ram 2 by the operation of the ram drive devices 10a to 10d.

Each of the ram driving devices 10a to 10d uses an AC servomotor 11a to 11d provided at the rear as a driving source and transmits the driving force to the ram 2 via a timing belt 12.
Are transmitted to a ball screw 13 connected to the servo motors 11a to 11
The rotational driving force of d is converted into a moving force in the vertical direction, and the work W
Is configured to generate a pressing force with respect to

The vertical position of the ram 2 is detected by linear encoders 14a to 14d provided corresponding to the positions of the drive shafts of the ram driving devices 10a to 10d, and the detected data is sent to an NC device (multi-axis NC device) 15 To the servo amplifiers 16a to 16a depending on the position of each axis.
The respective servo motors 11a to 11d are feedback-controlled via 6d. Here, the linear encoders 14a to 14d are connected to the side frames 7, 8 respectively.
Are supported by a correction bracket 17 which is constituted by two side plates provided along the line and beams connecting the left and right side plates. With such a configuration, the linear encoders 14a to 14d can measure the absolute position of each axis of the ram 2 without being affected by the deformation due to the load change of the side frames 7, 8.

An operation panel (pendant operation panel) 24 including an input / output device for inputting / outputting bending data and a display for displaying various data is suspended from the support frame 9 via a swingable arm 25. I have. An NC device 15 that performs calculations based on various data is provided on the side of the main body frame.
A control panel 20 containing a control device such as a servo amplifier is mounted. Further, a foot switch 26 for stepping operation is provided below the side of the body frame.

In the NC device 15, the operating position (slow position and lower limit position) of the ram 2, the moving speed of the ram 2 and the pressing force (pressure required for bending) are based on the bending data inputted from the operation panel 24. Is calculated. These data can be input by the operator from the operation panel 24.

When an operation command is given to the ram 2 by the operator stepping on the foot switch 26, the NC device 15 sends a speed command to the servo amplifiers 16a to 16d and the maximum value of the torque required for the ram operation (torque limit). Value). In the servo amplifiers 16a to 16d, the servo motor 11 is controlled by the given speed command and torque limit value.
Drive commands are issued to a to 11d. Also, encoders 18a to 18a built in the servomotors 11a to 11d are used.
The output pulse of 18d is fed back to the servo amplifiers 16a to 16d. The servo amplifiers 16a to 16d
The speed is calculated based on the signals from the encoders 18a to 18d, and the servo motors 11a to 11d are controlled so as to approach the speed signal input from the NC device 15.

On the other hand, the position feedback signals from the linear encoders 14a to 14d are input to the NC device 15, and the NC device 15 positions the ram 2 at the target position based on the position feedback signals.

In the press brake of this embodiment, a bending correction process is performed in the NC device 15 when the work W is bent by the lowering of the ram 2. Next, the processing flow of the deflection correction processing will be described with reference to the operation explanatory diagram shown in FIG. 4 and the flowchart shown in FIG.

S1: Bending data such as bending product information, processing information, and die information is input from the operation panel. S2: A slow start position (slow position) of the ram 2 is calculated based on the input data. The slow position is set in consideration of the fact that if the punch 5 attached to the ram 2 suddenly collides with the work W, the work W will be damaged or misaligned. S3: Each ram drive device 10a-10 taking into account deflection correction
The lower limit position of each drive shaft of d is calculated.

S4: The necessary pressure is calculated according to the input data in order to set the maximum value of the pressure applied to the workpiece W at the time of bending. S5: A position slightly before the highest position among the lower limit positions of the respective drive shafts calculated in step S3 is calculated as a synchronous control end position when the ram is lowered and a synchronous control start position when the ram is raised. S6: The worker starts to lower the ram 2 by stepping on the foot switch 26.

S7: From the upper limit position to the synchronous control end position, all the drive shafts are lowered horizontally at the same speed (at the same moving speed). In this case, as shown in FIG. 4, the vehicle descends at a high speed from the upper limit position to the slow position, and descends at a low speed from the slow position to the synchronous control end position. Further, when the vehicle enters the low-speed range, a force higher than a necessary pressure is not generated. S8: After reaching the synchronous control end position, the synchronous operation of all the drive shafts is released, and the drive shafts independently descend to the lower limit positions of the respective drive shafts. When the lower limit position is reached, the ram 2 is held for a predetermined time.

S9: When the machining is completed, each axis is independently raised to the synchronous control start position at the time of lifting. If the deviation of each axis is equal to or larger than the reference value at the end of machining, the axis rises while limiting the torque. S10 to S11: After each axis has risen to the synchronous control start position, all the drive axes are synchronized to rise to the upper limit position at high speed and stop at the upper limit position.

In this embodiment, in the bending process of the work W under the control of the ram 2 as described above, a stop command is issued for some reason while all the drive shafts are operating synchronously (steps S7 and S11). Then, the stop processing is executed according to the procedure shown in the flowchart of FIG. Hereinafter, the stop processing operation will be described with reference to this flowchart.

T1: All the drive shafts are synchronously controlled to lower or raise the ram 2. T2: A stop command is issued to the ram 2 by turning off the foot switch 26 or pressing a stop switch on the operation panel.

T3: The drive shaft at the time when the stop command is issued
The moving speed for the ram 2 and the speed until this moving speed becomes zero
The stopping distance is calculated from the deceleration time at. This stop distance
The separation is determined as follows. Drive shaft rated speed and
And the time from the rated speed until the speed becomes zero (during deceleration
Is set in the NC device 15 in advance. Shown in FIG.
As shown, when moving at a predetermined moving speed V
When a stop signal is issued, the system moves from this stop signal generation position.
The distance (stop distance) L traveled until the dynamic speed becomes zero is
Distance L₁And distance L₂Sum L₁+ L₂become. 1) Distance traveled while calculating the stopping distance: L₁  2) Distance traveled from the actual moving speed V until the speed becomes zero
Release: L₂  That is, the stop distance L is given by the following equation. L = V × T₁+ (V × T₂) / 2 where T₁: The preset NC equipment is stopped
Processing time T for calculating distance₂: Speed V obtained from the ratio of rated speed and actual speed V
The deceleration time until the speed becomes zero from the point where the deceleration is not a straight line as shown in FIG.
Stop in the same way, even if it is done with a curve like a curve
The distance can be calculated.

T4: When the ram descends, the value obtained by subtracting the stop distance L from the stop command generation position of the ram 2 is used as the new target stop position Ps. When the ram rises, the stop distance L is added to the stop command generation position of the ram 2. The added value is the new target stop position P
s (when the coordinate origin is set on the fixed table side). T5: The new target stop position Ps is compared with a preset target stop position of each drive shaft. T6: When the new target stop position Ps is located before the set target stop position, the new target stop position Ps is set to the stop position. T7: If the set target stop position is before the new target stop position Ps, the set target stop position is set to the stop position. T8: Stop all drive shafts driving the ram 2 at the set stop position.

As described above, according to the present embodiment, the ram 2
Even if a stop command is issued during the above synchronous control, all the axes can be stopped at the same position without deforming the ram while keeping the ram horizontal. Also, even when a restart command is issued, without checking the stop position of each drive shaft or checking the horizontal state of the ram,
Can be restarted.

In this embodiment, the invention is applied to a press brake having a high operating speed using an AC servomotor and a ball screw as a driving source of the ram. It can also be applied to a type using a cylinder.

In this embodiment, a press brake having four drive shafts has been described. However, the present invention is applicable to a press brake having a plurality of drive shafts including a two-drive shaft. Can be.

[Brief description of the drawings]

FIG. 1 is a front view of a press brake according to one embodiment of the present invention.

FIG. 2 is a side view of the press brake of the present embodiment.

FIG. 3 is a block diagram illustrating a configuration of a control system of the press brake according to the present embodiment.

FIG. 4 is a diagram illustrating an operation of a deflection correction process according to the embodiment;

FIG. 5 is a flowchart illustrating a process flow of a deflection correction process according to the embodiment;

FIG. 6 is a flowchart illustrating a processing flow of a stop process according to the embodiment;

FIG. 7 is an explanatory diagram of stop distance calculation.

[Explanation of symbols]

 Reference Signs List 1 fixed table 2 ram 4 die (lower die) 5 punch (upper die) 7, 8 side frame 9 support frame 10a to 10d ram drive device 11a to 11d AC servomotor 12 timing belt 13 ball screw 14a to 14d linear encoder 15 NC device 16a to 16d Servo amplifier 17 Correction bracket 18a to 18d Encoder 20 Control panel 24 Operation panel 26 Foot switch

Continued on front page F-term (reference) 4E063 AA01 BA07 DA18 DA19 FA01 FA05 JA03 LA03 LA08 LA12 LA14 LA17 4E089 CA01 DA02 DA05 5H269 AB09 BB03 CC01 EE01 EE05 EE10 EE11 GG01 GG06 JJ02 PP03 PP15

Claims (4)

[Claims] 1. A press for bending a plate material in cooperation with an upper mold supported by a ram having a plurality of drive shafts and a lower mold supported by a fixed table so as to face the upper mold. A ram stop control method for a brake, wherein when a stop command is issued during synchronous control for moving a ram by synchronizing each drive shaft, the moving speed of the drive shaft relative to the ram at the time of the stop command and the moving speed thereof Calculates the stop distance from the deceleration time until zero becomes zero, adds or subtracts the obtained stop distance to or from the stop command generation position to calculate the new target stop position, and sets all drive axes to the new target stop position. A ram stop control method for a press brake, wherein each drive shaft is controlled so as to stop the ram. 2. The new target stop position is compared with a preset set target stop position of each drive shaft. When the set target stop position is closer to the new target stop position, the set target stop position 2. The ram stop control of the press brake according to claim 1, wherein the drive shaft is stopped, and when the new target stop position is located before the set target stop position, all the drive shafts are stopped at the new target stop position. Method. 3. A press for bending a plate material by cooperation of an upper mold supported by a ram having a plurality of drive shafts and a lower mold supported by a fixed table so as to face the upper mold. A ram stop control device for a brake,
(A) When a stop command is issued during the execution of the synchronous control for moving the ram by synchronizing the respective drive shafts, the moving speed of the drive shaft relative to the ram at the time of the generation of the stop command and the deceleration until the moving speed becomes zero. (B) a new target stop position for calculating a new target stop position by adding or subtracting the stop distance obtained by the stop distance calculation unit to or from the stop command generation position. Ram stop for press brake, comprising: arithmetic means and (c) control means for controlling each drive shaft so as to stop all drive shafts at the new target stop position calculated by the new target stop position calculating means. Control device. 4. The apparatus further comprises comparing means for comparing the new target stop position with a preset target stop position of each drive shaft, wherein the control means sets the new target stop position to a new target stop position by the comparing means. When it is determined that the drive shaft is located before the stop position, all the drive shafts are stopped at the set target stop position, and when it is determined that the new target stop position is located before the set target stop position, the drive shaft is moved to the new target stop position. 4. The ram stop control device for a press brake according to claim 3, wherein the ram stop control device controls to stop all drive shafts.