JP2569126Y2 - Press brake - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press brake for bending a plate material, and more particularly, to a press brake having a drive device capable of individually moving up and down both left and right sides and a central portion of a ram. .

[0002]

2. Description of the Related Art Conventionally, in a type in which a ram is moved up and down in a press brake, a configuration in which hydraulic cylinders are arranged on both right and left sides of the ram is generally used.

[0003] When a plate material is bent in a press brake, the ram is of a both-end supporting type.
It is known that the center of the ram is concavely curved due to the drag of the plate material. When the ram curves concavely like this,
The bending angle at the center of the plate material is larger than the bending angles on both sides, and it is difficult to perform accurate bending.

Therefore, conventionally, a large number of wedge devices and the like are interposed between a ram and a mold mounted on the ram, and the mold is previously curved in a convex shape, so that a linear (horizontal) is formed when the plate material is bent. ). In this configuration, there is a problem that adjustment of the plurality of wedge devices is troublesome.

There is also a configuration in which a hydraulic cylinder is disposed at both sides of the ram and at the center of the ram, and the ram is bent in a convex shape by the hydraulic cylinder at the center.

[0006]

In the configuration in which the hydraulic cylinders are also provided at the center of the ram as described above, the pressure of the hydraulic pressure acting on the left and right cylinders and the cylinder at the center is adjusted. Although the ram can be curved in a convex shape, it is troublesome to determine whether the ram position in the curved state is the correct position.

[0007]

DISCLOSURE OF THE INVENTION In view of the above-mentioned conventional problems, the present invention provides a ram supporting an upper die vertically movable above a lower table supporting a lower die. A press configured to be capable of individually moving up and down the left and right sides and the vicinity of the center of the ram on a frame that supports the ram so that the ram can be corrected for the amount of vertical deflection of the ram. In the brake, a movement amount detection device capable of detecting the movement amount of the left and right side portions of the ram is provided, and when it is detected that the upper die abuts on the plate material while lowering while holding the horizontal state of the ram. The measurement of the movement amount by the movement amount detection device is started, and when the detection value of the movement amount reaches a set value, the lowering of the ram is stopped.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, FIG. 1 conceptually shows a press brake 1 according to an embodiment of the present invention.

In the present embodiment, a ram-down type press brake in which a ram 9 supporting an upper die 7 is vertically movable above a lower table 5 supporting a lower die 3 is illustrated. However, the present invention is not limited to the ram-down type press brake, but can be easily applied to the ram-up type press brake.

That is, in the present embodiment, the ram 9
In order to move the ram 9 vertically, a gate-shaped frame 11 is provided integrally with the lower table 5, and at the upper part of the frame 11, three or more driving devices for moving the ram 9 up and down are provided. .

More specifically, ball nuts 13A, 13B,
13C is attached, and each ball nut 13A, 13
B and 13C are screwed with ball screws 15A, 15B and 15C rotatably supported on the upper portion of the frame 11.

Accordingly, each of the ball screws 15A, 15A
By rotating B and 15C synchronously, the ram 9 is rotated.
Is moved up and down. In the above embodiment, the ball nut is mounted on the ram 9, but a ball screw may be mounted on the ram 9 and the ball nut may be rotatably mounted on the frame 11.

Each of the ball screws 15A, 15B, 15C
In order to rotationally drive the ball screws 15A, 15B,
Pulleys 17A, 17B, and 17C are attached to 15C, respectively. A timing belt 19 is provided between each pulley 17A, 17B, and 17C and each drive pulley of each of the servomotors M1, M2, and M3 mounted on the frame 11.
A, 19B and 19C are looped. A ram 9 that is moved by the rotation of each of the ball screws 15A, 15B, 15C.
In order to detect the amount of movement of each ball screw 15A, 15B
B and 15C are respectively connected to movement amount detecting devices E1, E2 and E3 such as pulse encoders.

Therefore, each servo motor M1, M2,
By rotating M3 synchronously, each ball screw 15
A, 15B and 15C can be rotated synchronously and the ram 9 can be moved up and down horizontally.

When the ram 9 is lowered and the plate material W is bent by the upper die 7 and the lower die 3, the ram 9 is bent with respect to the deflection amount of the ram 9 when the ram 9 is in a horizontal initial state (the deflection amount is zero). In order to detect the amount of bending of the ram 9, the ram 9 is provided with a bending amount detecting device 21.

More specifically, in this embodiment, a detection bar 25 whose one end is supported on one end of the ram 9 by a pin 23 is provided horizontally, and the detection bar 25 is horizontally provided at the other end of the detection bar 25. The pin 27 planted at the symmetric position of the ram 9 is fitted into the provided long hole 25H. And detection bar 2
For example, a proximity sensor 29 for detecting the detection bar 25 is attached to the ram 9 corresponding to the central portion in the longitudinal direction of 5.

Therefore, when the lower portion of the ram 9 is curved so as to be concave, the left and right sides of the ram 9 are in a state of being close to each other, but slippage occurs between the long hole 25H of the detection bar 25 and the pin 27. That is, the detection bar 25 is held horizontally. Further, the proximity sensor 29 is separated from the detection bar 25 by curving the lower portion of the ram 9 so as to be concave. Therefore, the amount of deflection of the ram 9 can be detected based on the detection value of the proximity sensor 29.

The lower table 5 is provided with a flexure amount detecting device 31 for detecting the flexure amount of the lower table 5. Since the bending amount detecting device 31 has the same configuration as that of the above-described bending amount detecting device 21, portions having the same functions are denoted by the same reference numerals, and detailed description is omitted.

Further, strain detectors 33L and 33R such as strain gauges are attached to the left and right sides of the frame 11 in order to detect the amount of strain on both the left and right sides of the frame 11 when the plate material W is bent.

Each servo motor M1, M2, M3
Are controlled and driven simultaneously or individually as appropriate under the control of, for example, a CNC control device (not shown).

In the above configuration, when the servo motors M1, M2, M3 are driven synchronously, the ram 9 is lowered while maintaining a horizontal state. Then, when the upper die 7 comes into contact with the plate material W on the lower die 3, each of the servomotors M1, M
Since the load of M2 and M3 fluctuates, it is possible to detect that the upper die 7 has contacted the plate material W by detecting, for example, a change in the current value.

When it is detected that the upper die 7 has come into contact with the plate material W, the movement after the contact with the plate material W is detected by the movement amount detecting devices E1, E2, E3 connected to the ball screws 15A, 15B, 15C. The quantity is measured. When the detected value of the movement amount reaches a preset value, the ram 9
Is stopped. That is, since the upper die 7 moves from the upper surface of the plate material W by the set value and the lowering of the ram 9 is stopped, the amount of protrusion of the upper die 7 with respect to the lower die 3 is accurate, and accurate bending is performed. Will be

In the above case, since the bending of the plate material W is generally performed at the left and right central portions, it is necessary to compare the average value of the detection values of the left and right movement amount detecting devices E1 and E2 with the set value. Is desirable.

When the lowering of the ram 9 is stopped as described above, the deflection amount of the ram 9 with respect to the initial state is detected by the deflection amount detecting device 21, and only the servomotor M2 at the center is driven based on the detected value. The deflection amount of the ram 9 can be corrected by making the detected value of the deflection amount of the deflection amount detecting device 21 equal to the detected value in the initial state before the start of the descent.

When the deflection of the ram 9 is corrected as described above, the detection value of the deflection detection device 31 provided on the lower table 5 is added to the detection value of the deflection detection device 21 of the ram 9, and this addition is performed. The deflection of the ram 9 is corrected based on the value. Further, the left and right distortion detectors 33L and 33R detect the left and right distortion amounts of the frame 11, and each servo motor is used to correct the distortion amount of the frame 11 based on the detection values of the left and right distortion detectors 33L and 33R. M1 and M3 are individually controlled.

For example, the servo motor M1 is controlled and driven to correct the amount of distortion on the left side of the frame 11 based on the detection value of the left distortion detector 33L, and based on the detection value of the right distortion detector 33R. In addition, the servo motor M3 is controlled and driven in order to correct an amount corresponding to the distortion amount on the right side of the frame 11.

[0027]

As will be understood from the above description of the embodiment, in the present invention, since the driving device capable of individually moving up and down on both the left and right sides and the center of the ram 9 is provided, the plate material W is provided. In addition to the fact that the ram 9 can be adjusted in the vertical direction in accordance with the processing state of the ram 9, in the present invention, the ram 9 is held down in a horizontal state, and the upper die 7 contacts the plate W. When the movement amount is detected by the movement amount detection device, the measurement of the movement amount is started, and when the detection value of the movement amount reaches the set value, the lowering of the ram 9 is stopped. The upper die 7 moves by the set value to stop the lowering of the ram 9, so that the amount of the upper die 7 protruding into the lower die 3 is accurately performed, and accurate bending can be performed. is there.

[0028]

[0029]

[Brief description of the drawings]

FIG. 1 is an explanatory view conceptually showing one embodiment of the present invention.

[Explanation of symbols]

 9 Ram M1, M2, M3 Driving device 21 Moving amount detecting device

Claims (1)

(57) [Scope of request for utility model registration] 1. A ram (9) supporting an upper mold (7) is vertically movable above a lower table (5) supporting a lower mold (3), and the ram (9) is moved up and down. A drive device capable of individually moving the ram (9) up and down on the left and right sides and near the center of the ram (9) is provided on a frame that can be supported so that the amount of vertical deflection of the ram (9) can be corrected. The press brake is provided with a moving amount detecting device capable of detecting the moving amount of the left and right sides of the ram (9), and lowering while holding the horizontal state of the ram (9).
Starts to measure the amount of movement by the movement amount detecting device when it detects that the ram (W) has come into contact with the plate material (W), and when the detected value of the movement amount reaches a set value, the ram ( 9) A press brake characterized in that the descent is stopped.