JP3274273B2 - Ram control method and apparatus for bending machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ram control method and apparatus for controlling a ram in a bending machine such as a press brake.

[0002]

2. Description of the Related Art Conventionally, for example, a press brake as a bending machine has a side frame, and a lower table (ram) which is vertically moved by a hydraulic drive cylinder is provided at a front side of the side frame. At the same time, an upper table as a fixed table is provided on the front upper portion of the side frame. A punch is provided below the upper table, and a die is provided above the lower table.

[0003] Therefore, the lower table is moved up and down by operating the hydraulic drive cylinder, so that the work placed on the die is bent in cooperation with the punch and the die.

A positioning member is provided for positioning an upper limit position of the lower table when the lower table is moved up and down. This positioning member is shown in FIG.
As known in Japanese Patent Application Publication No. 9-205, the lower table is moved up and down by a drive motor such as a servomotor, and the lower table is positioned by a dog provided on the lower table abutting a limit switch provided on a positioning member. It is supposed to be.

[0005]

In the above-mentioned conventional drive means for moving the lower table up and down, if the oil temperature in the hydraulic drive cylinder is low, the speed of the lower table cannot keep up with the speed of the positioning member. Sometimes. In this case, since the operation of the lower table is not normal, the operation of the press brake has been stopped as a tracking abnormality alarm.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and a device for controlling a ram in a bending machine in which the speed of the ram approaches the speed of a positioning member in the bending machine so that the ram can be accurately positioned without abnormal operation. To provide.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention moves a ram driven up and down by a hydraulic drive cylinder so as to be able to approach and separate from a fixed frame, and moves a positioning member up and down. In a method of controlling a ram in a bending machine that moves and positions the ram, an oil temperature in the hydraulic drive cylinder is detected by an oil temperature sensor, and the oil temperature is detected based on the oil temperature detected by the oil temperature sensor. It is characterized in that the elevating speed of the positioning member is controlled.

Further, the ram control device in the folding machine according to the present invention moves the ram driven up and down by the hydraulic drive cylinder so as to be able to approach and separate from the fixed frame, and also moves the positioning member so as to be able to move up and down. A ram control device for a bending machine for positioning the ram, wherein an oil temperature sensor for detecting an oil temperature in the hydraulic drive cylinder, and the positioning member based on the oil temperature detected by the oil temperature sensor. And a positioning member drive unit driven by a speed command value controlled by the positioning member speed control unit.

[0009]

With the method and apparatus for controlling the ram in the bending machine as described above, the oil temperature in the hydraulic drive cylinder is detected by an oil temperature sensor, and the detection signal detected by the oil temperature sensor is It is sent to the positioning member speed controller. In the positioning member speed controller, the speed of the positioning member is set based on the detected oil temperature, and the positioning member driving means is driven by the speed command.

Therefore, the positioning member is controlled in accordance with the oil temperature in the hydraulic drive cylinder, so that the speed of the ram approaches the speed of the positioning member and the vertical movement of the ram does not become abnormal.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

Referring to FIG. 5, for example, a press brake 1 as a bending machine has side frames 3 on both sides, and a lower table 5 as a ram which can be raised and lowered is provided at a lower front side of the side frames 3. Have been.
An upper table 7 as a fixed table is provided on an upper front side of the side frame 3.

A die D is mounted on the lower table 5, and a punch P facing the die D is mounted on a lower part of the upper table 7. The lower end of the lower table 5 is attached to the tip of a piston rod 11 mounted on a hydraulic drive cylinder 9 as shown in FIG.

Referring to FIG. 5 again, a control box 13 is provided on a side surface of the left side frame 3, and a control device 17 is provided on the control box 13 via a bracket 15. Control box 1
9 is a foot switch 21 provided in the foot device 19.
Is connected.

With the above configuration, when a work is mounted on the die D and the operator steps on the foot switch 21 of the foot device 19, the hydraulic drive cylinder 9 is operated and the lower table 5 is raised. As a result, the work is bent in cooperation with the punch P and the die D.

An oil temperature sensor 23 such as a normal temperature sensor for detecting the oil temperature of the lower cylinder chamber 9D is connected to the lower cylinder chamber 9D of the hydraulic drive cylinder 9. A dog 25 is mounted on the rear surface (the left side surface in FIG. 4) of the lower table 5.

To detect, for example, the upper limit position of the lower table 5, a positioning member 27 which can move up and down is provided, and a limit switch 29 is provided on the lower surface on the right side of the positioning member 27. The positioning member 27 has a ball screw 31 extending vertically.
And a servo motor 33 as a positioning driving means is connected to a lower portion of the ball screw 31.

With the above configuration, when the servo motor 33 is driven, the ball screw 31 is rotated. For example, the positioning member 27 rises and stops at the upper limit position. When the hydraulic drive cylinder 9 is operated, the lower table 5 is raised via the piston rod 11 and the dog 25
Comes into contact with the limit switch 29 and stops, and the lower table 5 is positioned at the upper limit position.

As shown in FIG. 1, the control device 17 includes a positioning member speed control unit 35.
The positioning member speed controller 35 has a data file 37 containing data representing the relationship between oil temperature and speed.
Is connected. Further, the oil temperature sensor 23 and the servo motor 33 are connected to a positioning member speed controller 35. Further, in the data file 37, data representing the relationship between the oil temperature and the speed as shown in FIG. 2 or 3, for example, is stored. In FIG. 2, data is stored in which the speed V increases stepwise as the oil temperature T increases. In FIG. 3, data is stored in which the speed V is proportionally increased as the oil temperature T increases.

With the above configuration, the lower cylinder chamber 9D of the hydraulic drive cylinder 9 detected by the oil temperature sensor 23
Is taken into the positioning member speed controller 35. Since the data representing the relationship between the oil temperature and the speed shown in FIG. 2 or FIG. 3 from the data file 37 is previously taken into the positioning member speed controller 35, the positioning member speed controller 35 sets the actual oil temperature to An appropriate speed command value is set based on this. The appropriate speed command value is output to the servo motor 33 and the servo motor 33 is controlled and driven, whereby the speed of the lower table 15 is controlled so as to approach the speed of the positioning member 27.

Therefore, the oil temperature of the lower cylinder chamber 9D of the hydraulic drive cylinder 9 is detected by the oil temperature sensor 23, and the servo motor 33 of the positioning member driving means is driven at a speed corresponding to the oil temperature at that time. In addition, the speed of the lower table 5 can be made as close as possible to the speed of the positioning member 27, and the position of the lower table 5 in the vertical movement is accurate, so that abnormal operation does not occur and the press brake 1 does not stop abnormally. As a result, the accuracy of the bending process can be improved and the productivity can be improved.

The present invention is not limited to the above-described embodiment, but can be embodied in other forms by making appropriate changes. In the present embodiment, the folding machine 1 in which the lower table 5 is a ram and the upper table 7 is a fixed table has been described, but the folding machine in which the upper table 7 is a ram and the lower table 5 is a fixed table. It may be 1.

[0023]

As will be understood from the above description of the embodiment, according to the present invention, the oil temperature in the hydraulic drive cylinder is detected by the oil temperature sensor, and the oil temperature detected by the oil temperature sensor is detected. Since the speed of the positioning member is controlled based on the temperature, the speed of the hydraulic drive cylinder can be made as close as possible to the speed of the positioning member,
The ram can be accurately positioned without causing abnormal operation.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of a ram control device in a bending machine according to the present invention.

FIG. 2 is an example diagram showing a relationship between oil temperature and speed stored in a data file.

FIG. 3 is an example diagram showing a relationship between oil temperature and speed stored in a data file.

FIG. 4 is an explanatory view showing a moving mechanism of a lower table and a positioning member.

FIG. 5 is a perspective view of a press brake according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 press brake (bending machine) 5 lower table (ram) 7 upper table (fixed table) 9 hydraulic drive cylinder 17 controller 23 oil temperature sensor 25 dog 27 positioning member 29 limit switch 33 servo motor (positioning member driving means) 35 Positioning member speed controller 37 Data file

Claims (2)

(57) [Claims] 1. The ram in a bending machine that moves a ram driven up and down by a hydraulic drive cylinder so as to approach and separate from a fixed frame, and moves a positioning member so as to be able to move up and down to position the ram. In the control method, an oil temperature in the hydraulic drive cylinder is detected by an oil temperature sensor, and the elevation speed of the positioning member is controlled based on the oil temperature detected by the oil temperature sensor. To control the ram on the machine. 2. A ram in a bending machine that moves a ram driven up and down by a hydraulic drive cylinder so as to approach and separate from a fixed frame and moves a positioning member so as to be able to move up and down to position the ram. In the control device, an oil temperature sensor that detects an oil temperature in the hydraulic drive cylinder, a positioning member speed controller that controls the speed of the positioning member based on the oil temperature detected by the oil temperature sensor, A driving device for a positioning member driven by a speed command value controlled by a positioning member speed control unit.