JPH0757394B2 - Press machine dicing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a die cushion device for a press machine.

[Prior Art] FIG. 2 shows an example of a conventional press machine, in which a lower die c is provided on a bolster plate b provided on a bed a, and further penetrates the bolster plate b to provide an upper end. Is provided with a pin f having a lower mold outer e for receiving the material d, and a pin plate g provided at the lower end of the pin f is supported on a die cushion h composed of a multi-stage air cylinder. The upper mold i is clamped by pressing the material d against the outer mold e of the lower mold to clamp the material d, and by further descending in the clamped state, the upper and lower molds i, c The material d is shaped by the method described above. In the figure, k indicates a soundproof wall provided so as to cover the press device, and 1 indicates an opening / closing door provided on the soundproof wall k for loading and unloading the mold when the mold is replaced.

[Problems to be Solved by the Invention] However, in the press machine as described above, when the upper die i first hits the material d (when the material is clamped by the upper die and the lower die outer), It makes a big impact sound (metal sound) and is a problem.

For this reason, conventionally, a heavy soundproof wall k is provided, and at this time, an opening / closing door 1 is provided on the soundproof wall k for the purpose of exchanging a mold or the like, but it is very large. Despite the expensive and expensive construction, it was not very effective in soundproofing.

Further, since the die cushion device in the above-mentioned conventional system is a cushion system using an air cylinder, the pressure receiving surface is large, and therefore the required cushion pressure can be obtained unless it is a multi-stage system to be stored in a limited space. Therefore, there is a problem that the structure becomes large and complicated.
Furthermore, a large air tank is required to reduce the fluctuation of the cushion pressure, and it is necessary to replenish or release the air in the tank to change the required cushion pressure each time the mold is replaced, which is a waste. There was a problem that the work took time as it occurred.

The present invention was made by focusing on the above-mentioned conventional problems,
An object of the present invention is to provide a die cushion device having a small structure and good operability, and further preventing generation of impact noise when the upper die first contacts the material.

[Means for Solving Problems] The present invention is intended to solve the above technical problems,
A hydraulic piston cylinder having a piston connected to a cushion pad, a lower oil chamber connected to an oil tank via a relief valve, and an upper oil chamber is provided, and a lifting piston integrally connected to the piston. And a push-up cylinder configured to push up the cushion pad by a hydraulic accumulator, and configured to supply pressure oil of the hydraulic accumulator to an upper oil chamber of the hydraulic cushion cylinder via a servo valve, A position detector is provided to detect the position immediately before the upper die comes into contact with the material, and the servo valve is operated to push down the cushion pad by immediately supplying pressure oil to the upper oil chamber in response to a signal from the detector. The present invention relates to a die cushion device for a press machine, which is provided with a control device.

[Operation] Therefore, according to the present invention, the position immediately before the upper die first comes into contact with the material is detected, and the servo valve is immediately activated by the detection signal to lower the cushion pad so that the pressure oil of the hydraulic accumulator is moved to the hydraulic cushion. Since the oil is supplied to the upper oil chamber of the cylinder, the lowering speed of the upper mold and the lowering speed of the cushion pad at the time of contact can be made approximately equal to prevent the generation of impact noise. As a result, the structure of the cushion cylinder is reduced in size, and the hydraulic accumulator is operated to improve the operability.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the present invention. In FIG. 1, reference numeral 1 denotes a hydraulic cushion cylinder. Inside the hydraulic cushion cylinder 1, a piston 3 connected to a cushion pad 2 on the upper outer side is provided. An upper oil chamber 4 and a lower oil chamber 5 are formed by 3.

Further, a push-up cylinder 8 having a push-up piston 7 connected to the piston 3 by a shaft 6 so as to move integrally with the piston 3 is provided below the hydraulic cushion cylinder 1.

The oil in the oil tank 9 is supplied to the upper oil chamber 4 of the hydraulic cushion cylinder 1 via a pump 10, a check valve 11 and a servo valve 12.

Further, the throttle valve 14 is provided between the upper oil chamber 4 and the oil tank 9.
Further, the switching valve 15 and the check valve 16 are connected by a circuit provided in parallel.

The pressure oil from the check valve 11 is guided to the hydraulic accumulator 17 and the switching valve 15. An unload circuit having a relief valve 18 and a switch 19 for returning oil to the oil tank 9 is provided between the check valve 11 and the pump 10.

Further, the lower oil chamber 5 of the hydraulic cushion cylinder 1 and the oil tank 9 are connected by a circuit provided with a relief valve 20 and a check valve 21 in parallel.

Further, a circuit for introducing the pressure oil from the pump 10 into the hydraulic accumulator 23 and the lifting cylinder 8 via the switching valve 22 is provided.

In the above configuration, a position detector 27 such as a limit switch for detecting the position immediately before the upper die 24 contacts the material 26 is provided, and a signal from the position detector 27 is guided to the control device 28 to cause the servo valve 12 to operate. It is configured to perform the switching control of. In the figure
29 is a lower mold, and 2 is a lower mold outer.

Before the press work, the pressure oil of the hydraulic accumulator 23 is introduced into the lifting cylinder 8 and the piston 7 is pushed up, and thereby the piston 3 of the hydraulic cushion cylinder 1 is also pushed up. At this time, the lower oil chamber 5 is checked. The oil in the oil tank 9 is sucked through the valve 21, and the oil in the upper oil chamber 4 is discharged to the oil tank 9 while being throttled through the throttle valve 14 by switching the switching valve 15, and the cushion pad 2 reaches the upper limit. positioned.

When the upper die 24 descends during the press work, the position detector 27 detects it just before contacting the material 26, and the servo valve 12 is actuated via the control device 28 by the detection signal and the hydraulic accumulator. The pressure oil 17 is supplied to the upper oil chamber 4 of the hydraulic cushion cylinder 1 in a short time, and the oil in the lower oil chamber 5 of the hydraulic cushion cylinder 1 is compressed to push down the cushion pad 2. At this time, the amount of oil supply is controlled by the servo valve 12 so that the descending speed of the upper mold 24 when the upper mold 24 contacts the material 26 and the descending speed of the cushion pad 2 become substantially equal. As a result, a gentle contact is made and the generation of impact noise is prevented. Cushion pad 2 for loose contact
Of the upper mold 24 and the lower mold outer clamp 25 after the material is clamped is performed by returning the oil in the lower oil chamber 5 to the oil tank 9 via the relief valve 20. Cushioning effect is exhibited by the set pressure of. Further, the oil in the oil tank 9 is sucked into the upper oil chamber 4 through the check valve 16 during the rapid lowering of the piston 3 after being synchronized.

When the upper die 24 is raised, the pressure oil of the hydraulic accumulator 23 is introduced into the push-up cylinder 8 to push up the piston 7 to push up the cushion pad 2, and at this time, the lower oil chamber 5 of the hydraulic cushion cylinder 1 is pushed up. The oil in the oil tank 9 is sucked through the check valve 21, and the oil in the upper oil chamber 4 is returned to the oil tank 9 through the throttle valve 14 and the switching valve 15.

Oil leakage from the lifting cylinder 8 is performed by sending pressure oil from the pump 10 through the switching valve 22, and the oil in the used hydraulic accumulator 17 is supplemented by the pump 10 by the next cycle. , Relief valve after compensation
It is unloaded by 18 and the switching valve 19 and returned to the oil tank 9.

The present invention is not limited to the above-described embodiments, but the detection method and the detection position of the position detector can be variously changed, the present invention can be applied to die cushions of various press machines, and other aspects of the present invention. It goes without saying that various changes can be made without departing from the scope of the invention.

[Effects of the Invention] As described above, according to the press impact sound absorbing device of the press machine of the present invention, when the upper die comes into contact with the material, the cushion pad is operated so as to be lowered so that the cushion pad is brought into a gentle contact. As a result, it is possible to significantly reduce the generation of impact noise at the time of contact, and thus it is possible to significantly simplify or omit the structure of the soundproof wall. Furthermore, by adopting a hydraulic cylinder for the die cushion, the size of the device can be reduced. In addition, the hydraulic accumulator is used to lower the cushion pad and push up the cushion pad to prevent the impact noise from being generated, which allows quick operation and improved operability. It is possible to achieve excellent effects such as

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention, and FIG. 2 is an explanatory view showing an example of a conventional die cushion device. 1 is a hydraulic cushion cylinder, 2 is a cushion pad,
4 is an upper oil chamber, 5 is a lower oil chamber, 8 is a lifting cylinder, 9
Is an oil tank, 10 is a pump, 12 is a servo valve, 14 is a throttle valve,
15 is a switching valve, 16 is a check valve, 17 is a hydraulic accumulator, 20 is a relief valve, 21 is a check valve, 22 is a switching valve, 23
Is a hydraulic accumulator, 24 is an upper mold, 26 is a material, 27 is a position detector, and 28 is a controller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuki Yamamoto 1st Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishi Kawashima Harima Heavy Industries Co., Ltd. Yokohama Second Factory (56) A) Actual opening Sho 58-166928 (JP, U) Actual opening Sho 59-73028 (JP, U) Actual opening Sho 60-176823 (JP, U) Actual public Sho 53-24915 (JP, Y1)

Claims (1)

[Claims] A hydraulic cushion cylinder having a lower oil chamber connected to an oil tank via a relief valve and an upper oil chamber is provided, and the piston is integrated with the cushion pad, and is integrally connected to the piston. A push-up cylinder that has a push-up piston that is pushed up and pushes up the cushion pad by a hydraulic accumulator, and supplies pressure oil of the hydraulic accumulator to the upper oil chamber of the hydraulic cushion cylinder via a servo valve. And a position detector for detecting the position just before the upper die comes into contact with the material, and pressure oil is immediately supplied to the upper oil chamber by a signal from the detector to push down the cushion pad. A die cushion device for a press machine, comprising a control device for operating a servo valve.