JPH1076323A - Automatic pressure regulation die cushion structure for metal sheet press machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the formability of a product, to execute drawing, etc., without causing any wrinkles or cracks, to reduce futile energy consumption and to simplify the structure of a die by automatically combining and controlling a hydraulic pressure means and a pneumatic pressure means. SOLUTION: At the time of drawing a work of metal sheet, an oil chamber cylinder 4 and an air chamber 5 are moved with the pressing force caused by the lowering of a slide of a press machine while being linked with the slide speed, then an air inside the air chamber 5 is compressed and the hydraulic oil inside an oil chamber cylinder 4 regulates the pressure of a die cushion device 1 by a diaphragm of a magnetic solenoid valve 7. The pressure inside the oil chamber cylinder 4 is read out as occasion demands by a pressure sensor 11 arranged on the oil chamber cylinder 4, it is inputted to a main controller 9, a desired pressure regulation pattern is decided based on the read out pressure, and a desired command is outputted to a valve controller 10. Based on data of a personal computer 8, the pattern is changed or re-realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic pressure adjusting die cushion structure for a plate press machine.

[0002]

2. Description of the Related Art In a conventional press working of a sheet press machine, a die cushion device serving as a plate press, which has been used mainly when drawing a plate material work, is well known as a method of generating pressure. , Pneumatic, hydraulic and combined pneumatic / hydraulic types.

[0003] FIG. 4 (a) shows a characteristic diagram of a stroke of a slide of a press machine and a plate presser pressure value, respectively, of a pneumatic type and a hydraulic type (including a pneumatic type) as typical structures thereof.
(B).

(A) In the case of the pneumatic type, compressed air is previously filled in an air cylinder or a bellows to set a predetermined pressure, and when press drawing is performed, the working pressure applied by the slide descending is reduced. A reaction force is applied to adjust the stop state of the product work.

(B) In the case of the pneumatic type, the hydraulic oil is filled in the cylinder, and the hydraulic oil which is about to be discharged out of the cylinder is pushed by the hydraulic cylinder by the downward force of the slide. To generate a nearly constant pressure by controlling the oil to escape, and once the hydraulic oil is discharged,
The hydraulic cylinder is pushed up by the pressure of a separately provided air chamber to suck in hydraulic oil.

[0006] The function of applying a work pressing reaction force to the pressing force of the slide during the above-described drawing is the same in both the pneumatic type and the pneumatic and hydraulic type. The pressure fluctuations in the die cushion have different patterns as shown in FIGS. 4 (a) and 4 (b).

[0007] (a) In the case of the pneumatic type, the internal pressure increases in proportion to the lower limit of the stroke of the slide, so that an unnecessary pressing force is applied to the work product, and the product is broken. It causes the phenomenon.

On the other hand, in the case of the conventional hydraulic type (b), there is a rising surge pressure at the beginning of the slide stroke, but the pressure can only be controlled to be constant thereafter. Could not be given a pressing reaction force having an optimum characteristic curve.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described aspects, and in a sheet material press working machine, conventionally, as described above, the pressing force of a die cushion during work drawing is reduced. The die cushion pressure is not limited to the pneumatic type incremental type or the hydraulic type constant characteristic, and the optimum plate holding force characteristic is given each time according to the processing characteristics of the product to improve the formability. An object of the present invention is to provide an automatic pressure adjusting die cushion device that can be improved.

[0010]

For this reason, in the present invention, the plate holding pressure of the plate die-cushion device at the time of drawing of a plate material pressing machine is controlled by the stroke of the press slide. An automatic pressure adjusting die cushion device for a sheet material press working machine, characterized in that it is configured to automatically control combination of hydraulic and pneumatic pressurizing means so that a pressure curve suitable for processing characteristics is obtained, The purpose of the present invention is to achieve the above object.

[0011]

According to the structure of the present invention as described above, it is possible to provide a press slide stroke versus a die cushion pressure having a characteristic curve suitable for the processing characteristics of the product work, thereby improving the formability of the product. Further, processing that has been conventionally difficult can be performed.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing the construction of an embodiment of an automatic pressure-regulating die cushion structure of a plate press machine according to the present invention.
FIG. 2 shows four examples of the slide stroke versus die cushion pressure characteristic pattern.

(Construction) In FIG. 1, a die cushion device 1 according to an embodiment of the present invention is configured such that a desired pressure characteristic curve can be obtained by combining hydraulic and pneumatic characteristics. (Oil) tank 2 and air tank 3
The die cushion device 1 includes an oil chamber cylinder 4 and an air chamber 5.

The hydraulic circuit has a check valve 6 and an electromagnetic solenoid valve 7 between the oil chamber cylinder 4 and the oil tank, respectively. It is controlled by a valve controller 10 via a controller 9.

The oil chamber cylinder 4 is provided with a pressure sensor 11, the output of which is configured to be input to the main controller 9.

On the other hand, the air chamber 5 is connected to an air tank 3 supplied from an external air circuit, and the tip of a rod 12 fixed to the air chamber 5 slides up and down in an oil chamber cylinder 4. A die cushion pad 13 is provided.

(Operation) At the time of drawing work of a plate material,
The oil chamber cylinder 4 and the air chamber 5 move in conjunction with the sliding speed due to the pressing force due to the lowering of the slide of the press machine, the air in the air chamber 5 is compressed, and the hydraulic oil in the oil chamber cylinder 4 is The pressure of the die cushion device 1 is adjusted by restricting the electromagnetic solenoid valve 7.

When the slide is lifted, the cushion pad 13 is raised by air pressure, so that the oil chamber 4 is raised.
Hydraulic oil is sucked into the cylinder from the check valve 6 side.

(Pressure Adjusting Method) The pressure sensor 11 disposed in the oil chamber cylinder 4 reads the internal pressure of the oil chamber cylinder 4 as needed, and based on the pressure inputted to the main controller 9 and shown in FIG. A desired pressure regulation pattern showing the four examples is determined, and a required command is issued to the valve controller 10. These patterns are changed and reproduced according to the data of the personal computer 8.

(Pressure Control Pattern) The pressure characteristic patterns of the four typical examples shown in FIG. 2 are not limited to these, but the shape, processing accuracy, material,
It is selected according to the required quality and the like, and controls the die cushion pressure during the molding to change the plate pressing force on the product, that is, to perform a so-called "pressure regulation" action. For example, in the pattern, when it is desired to prevent the work from cracking, the pressure is reduced as the descending stroke of the slide advances.

The pattern shows an example in which the pressure is increased at the final point of the stroke when it is desired to prevent wrinkles (wrinkles) at the flange 14 in the hat-shaped product example shown in FIG.

(Other Embodiments) In the above embodiment, the electromagnetic solenoid valve 7 is used for controlling the pressure in the oil chamber cylinder 4. However, the present invention is not limited to this. However, pressure control is possible. That is, for example, the following examples can be used.

1) A conventional manual pressure regulating valve is
A method of directly controlling with a servo motor or a cam linked to the slide movement of a press, 2) A method of controlling pressure by replacing a conventional manual pressure regulating valve with an air cylinder or a hydraulic cylinder, 3) Use other types of solenoid valves (servo valves, etc.)
Such.

[0025]

As described above, according to the present invention,
Since the optimum die cushion pressure can be automatically adjusted according to the processing characteristics of the product of the plate material press machine, the formability of the product is improved, for example, wrinkles (wrinkles) are not generated or cracks are generated. It is possible to perform drawing or the like without unnecessary pressure, and by avoiding unnecessary pressurization, it is possible to suppress unnecessary energy consumption and to simplify the mold structure.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of an embodiment of a self-regulating die cushion structure.

FIG. 2 shows four examples of slide stroke versus die cushion pressure characteristic patterns.

Fig. 3 Example of hat-shaped product

FIG. 4 is a characteristic diagram of a plate presser pressure value with respect to a slide stroke.

[Explanation of symbols]

 Reference Signs List 1 die cushion 2 oil tank 3 air tank 4 oil chamber cylinder 5 air chamber 6 check valve 7 electromagnetic solenoid valve 8 personal computer 9 main controller 10 valve controller 11 pressure sensor 12 rod 13 die cushion pad 14 flange

Claims (1)

[Claims] 1. A method of controlling a plate holding pressure of a plate material die cushion device at the time of drawing of a plate material pressing machine so as to obtain a pressure curve suitable for a processing characteristic of each plate material work with respect to a stroke of a press slide. An automatic pressure adjusting die cushion device for a plate material pressing machine, wherein a hydraulic type and a pneumatic type pressing means are automatically combined and controlled.