JP2941181B2 - Opposing hydraulic forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opposing hydraulic forming apparatus for drawing a blank such as a thin plate to form automobile parts, electric parts, aircraft parts and the like.

[0002]

2. Description of the Related Art In an opposed hydraulic press, a material is caused to protrude in a gap between a punch and a blank holder. Vol. 214 (June 1963), page 724-
On page 725, in the left column, 6. In one aspect of hydraulic action,
"The following three points have already been pointed out as guidelines for using the features of this method and obtaining good drawing results." It is hoped that the material will be so-called "reverse overhang" to thereby improve the aperture ratio. " In addition,
Japanese Patent Publication No. -3622 proposes providing a blank holder with a constant curved portion in order to make the amount of reverse overhang constant. In addition, Japanese Patent Publication No. 57-780 which has already been proposed
The same has been proposed in the molding method of Japanese Patent Application Laid-Open No. 9-99.

[0003]

However, when the product is to be overstretched for the purpose of improving the drawing ratio as described above, the product is first formed, the presence or absence of breakage and the condition of wrinkles are observed, and wrinkle control for the stroke is performed. It is necessary to set the force and the generated hydraulic pressure, but depending on the variation of the material of the material and the lubrication state, the quality of the product occurs even with the same setting. Also, as in the latter case, if a curved part is formed on the blank holder,
If the above conditions change, the effect of reverse overhang may not be produced.

[0004] The present invention solves the above problems, improves the drawing ratio by effectively utilizing the reverse overhang, and is capable of stably producing a good product without breakage or wrinkles. An object is to provide a molding device.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an opposed hydraulic forming apparatus according to the present invention comprises a die disposed on a cylinder disposed at one end of a frame to form a hydraulic chamber; At the other end of the frame, a blank holder device that holds the peripheral edge of the blank material on the die is provided, and a press cylinder device that can drive the press punch and press the blank material into the hydraulic chamber is provided. When the blank material is pushed into the hydraulic chamber by the punch, a reverse overhang amount detector for detecting the reverse overhang amount generated in the blank material by the initial pressure is provided,
A control device for controlling the hydraulic pressure of the hydraulic chamber based on the detection value of the reverse overhang detector is provided.

[0006]

According to the above arrangement, by controlling the hydraulic pressure in the hydraulic chamber based on the detection value of the reverse overhang amount detector, variations in the blank material and the lubrication state may change. In addition, since the amount of reverse overhang can be kept constant, the reverse overhang can always be used effectively to improve the drawing ratio, and a good product without breakage or wrinkles can be produced.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of an opposed hydraulic forming apparatus according to the present invention. A cylinder 3 forming the hydraulic chamber 2 is provided on the bed 1 a of the frame 1, and a die 4 is provided facing an upper surface opening of the cylinder 3. On the other hand, a press cylinder device 6 for supporting the press punch 5 up and down is provided on the crown portion 1b of the frame 1.
Is provided, and a blank holder device 7 for pressing and holding the peripheral edge of the blank material W on the die 4 via a holding member 7B by a hold cylinder device 7A is provided.

The holding member 7B of the blank holder device 7 is formed with a small radius portion 7a at the corner between the bottom surface and the inner surface to smoothly project the reverse, and the reverse tension of the blank material W on the inner surface. A plurality of reverse swelling amount detectors 8 for detecting the output amount β are arranged, and the detected values are
It is configured to be inputted to. The reverse overhang detector 8 is preferably a non-contact type such as a laser type displacement meter, but may be a contact type strain displacement meter. The hydraulic chamber 2 is connected to a liquid supply pipe 11 for supplying a liquid to the hydraulic chamber 2 and a liquid discharge pipe 13 for controlling the hydraulic pressure of the hydraulic chamber 2 through a relief valve 12. , A pressure detector 14 for detecting the hydraulic pressure of the hydraulic chamber 2 is provided. The relief valve 12 is operated by an operation signal output from the control device 9 based on the detection signal from the reverse overhang amount detector 8 and the detection signal from the pressure detector 14, and the fluid in the hydraulic pressure chamber 2 is adjusted. The pressure is controlled so that the reverse overhang amount β of the blank material W is constant.

The press cylinder device 6 is supplied with a predetermined hydraulic pressure from a press hydraulic supply device 15 by a signal from the control device 9 to start the press punch 5. The hold cylinder device 7A is provided with a control device. A predetermined pressure is supplied from the holding hydraulic pressure supply device 16 in response to the signal of No. 9 to hold the blank material W at an appropriate pressure.

In the above configuration, when the blank material W is placed on the die 4 and the peripheral edge of the blank material W is pressed and held by the blank holder device 7, the press hydraulic supply device 15 transfers the blank material W to the press cylinder device 6. When the hydraulic pressure is supplied, the press punch 5 is lowered, and the blank material W is pushed into the hydraulic pressure chamber 2 side. Then, the initial pressure of the hydraulic chamber 2 causes the blank material W to reversely project at the periphery of the pressing portion of the press punch 5, and the reverse projecting amount β is detected by the reverse projecting amount detector 8 and controlled. Input to the device 9. The control device 9 compares the detected value with the reference reverse overhang amount input in advance from the setting unit 17, and when the reverse overhang amount β is larger than the reference reverse overhang amount, an open signal is sent to the release valve 12. Is output to reduce the hydraulic pressure in the pressure chamber 2. On the contrary, if the reverse overhang amount β is smaller than the reference reverse overhang amount, a close signal is output to the relieving valve 12 to output the hydraulic pressure in the pressure chamber 2. By reducing the amount of decompression and increasing the pressure,
The reverse overhang amount β is controlled to be within an appropriate range. Further, the press punch 5 is pushed into the hydraulic chamber 2 to continue the press working, and ends at the bottom dead center.

According to the above embodiment, by controlling the hydraulic pressure of the hydraulic pressure chamber 2 based on the detection value of the reverse overhang amount detector 8, the variation in the material of the blank material W and the lubrication state change. In some cases, the reverse overhang amount β for each blank material W
Can be maintained within an appropriate range, so that the reverse overhang can be effectively used to improve the drawing ratio, and a good product without breakage or wrinkles can be stably produced.

[0012]

As described above, according to the opposed hydraulic forming apparatus of the present invention, even if the material of the blank material varies or the lubrication state changes, the value detected by the reverse overhang amount detector can be improved. By controlling the hydraulic pressure in the hydraulic chamber based on the pressure, the amount of reverse overhang can be kept constant for each blank material. It is possible to stably produce good products without any problems.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an opposed hydraulic forming apparatus according to the present invention.

[Explanation of symbols]

 W blank material β reverse overhang 1 frame 2 hydraulic chamber 3 cylinder 4 die 5 press punch 6 press cylinder 7 press blank holder 7A hold cylinder 7B hold member 8 reverse overhang detector 9 controller 12 Relief valve 13 Liquid discharge pipe 14 Pressure detector

Continuation of front page (56) References JP-A-57-146427 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21D 22/20

Claims (1)

(57) [Claims] 1. A die is disposed on a cylinder disposed at one end of a frame to form a hydraulic chamber, and a blank holder device is provided at the other end of the frame for holding a peripheral edge of a blank material on the die. At the same time, a press cylinder device that can drive the press punch and push the blank into the hydraulic chamber is provided, and when the blank is pushed into the hydraulic chamber by the press punch, the reverse tension generated in the blank by the initial pressure Counter-hydraulic forming, comprising a reverse overhang amount detector for detecting the output amount, and a control device for controlling the hydraulic pressure of the hydraulic chamber based on the detection value of the reverse overhang amount detector. apparatus.