JPH0723056Y2 - Upper limit damper device for pneumatic die cushion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a damper device for a pneumatic die cushion device used in a press machine, and an upper limit damper for cushioning a shock when the die cushion device returns to an upper limit. Regarding the device.

[Conventional technology]

FIG. 2 shows a pneumatic die cushion device 10 incorporated in a press machine for blank wrinkling and a conventional upper limit damper device 11 for cushioning the impact of the die cushion device 10 when the upper limit is restored. .

Inside a bed 12 of a press machine, a piston 14 is fixedly mounted on a bottom member 13, and a cushion cylinder 15 having an air pressure chamber 15A inside is fitted in the piston 14 in a vertically slidable manner. A cushion pad 16 is attached to the cushion cylinder 15, and a cushion pin 17 provided upright on the cushion pad 16 vertically penetrates a bolster 18,
A blank holder 19 for pressing wrinkles is fixedly mounted on the upper end of the blank holder 19.
The piston 14, the cushion cylinder 15, the cushion pad 16 and the like constitute the pneumatic die cushion device 10. In the air pressure chamber 15A of the cushion cylinder 15, the air from the air pressure source has an air circuit 21 and a pipe.
Supplied via 22.

A piston rod 24 hangs down from the cushion cylinder 15, the piston rod 24 extends to an oil case 23, and a piston 25 at the lower end of the piston rod 24 moves up and down in an oil sump 23A inside the oil case 23. A cylinder portion 26 that opens downward is provided at the top of the oil sump portion 23A, and the inside diameter of this cylinder portion 26 matches the outside diameter of the piston 25. The inside of the tubular portion 26 and the oil sump portion 23A are connected via a hydraulic circuit 27 for oil circulation, and the hydraulic circuit 27 includes a check valve 28 and a throttle valve.
29 and a tank 30 are provided.

The piston 25, the cylinder portion 26, the hydraulic circuit 27, and the like constitute the upper limit damper device 11.

When the slide 31 of the press machine descends and the blank 34 is pressed by the upper die 32 and the lower die 33, the flange portion 34A of the blank 34 is sandwiched between the upper die 32 and the blank holder 19,
Blank holder 19 and cushion pin as upper mold 32 descends
17, cushion cylinder 15 through cushion pad 16
Is pushed down. Therefore, the air pressure chamber 15A, or the tank 20, and the chamber 3 connected to the air pressure chamber 15A by the pipe 35
The air of 6 is compressed, and the upward cushioning force due to this air compression acts on the blank holder 19 during the pressing operation, so that the blank 34 is pressed while wrinkles are prevented from being generated on the flange portion 34A.

When the slide 31 starts to rise after reaching the bottom dead center, the cushion cylinder 15, the cushion pad 16 and the like rise due to the air pressure, and the piston 25 that always moves up and down together with the cushion pad 16 and the like also rises. When the piston 25 is fitted into the cylinder portion 26, the oil in the cylinder portion 26 is pushed out to the hydraulic circuit 27, and the amount of oil flowing through the hydraulic circuit 27 is limited by the throttle valve 29, so that the blank holder 19 etc. The returning speed of the die cushion device 10 when approaching is reduced, the impact at the time of returning to the upper limit is alleviated, and the die cushion device 10 and the blank 34 are protected.

[Problems to be solved by the invention]

In the pneumatic die cushion device 10 described above, the cushion force is changed according to the type of the pressed product, that is, the type of the blank 34, and this cushion force is adjusted by changing the air pressure of the air circuit 21. Be seen. When the cushion force is adjusted in this way, the damper force of the damper device 11 must be changed in order to appropriately reduce the impact as required.

However, in the above conventional damper device 11, the damper force is constant unless the throttle amount of the throttle valve 29 is adjusted. For this reason, when the cushion force is increased, the damper force becomes relatively small, and it is not possible to appropriately mitigate the impact.
On the other hand, when the cushion force is reduced, the damper force is relatively increased, and the blank holder 19 stops during the stroke of returning to the ascending state, and in some cases, the blank holder 19 rapidly rises after that and the blank 34 is flipped up. May cause.

The object of the present invention is to automatically change the damper force according to the cushioning force without adjusting the throttle valve, etc., so that the magnitude of the damper force relative to the cushioning force can always be set appropriately. There is a device damper device.

[Means for solving problems]

Therefore, the device according to the present invention is a damper device provided in a pneumatic die cushion device that generates a cushioning force by compressing the air in the cushion cylinder, and moves vertically in the oil sump together with the cushion pad of the die cushion device. In the upper limit damper device configured to include a piston, a cylinder part that is fitted when the piston moves up, and a hydraulic circuit connected to the cylinder part, the hydraulic pressure from the cylinder part acts on the hydraulic circuit. A hydraulic circuit opening / closing valve is provided, and an air pressure adjusting means is provided in an air circuit for supplying air to the cushion cylinder, and the air pressure of the air circuit adjusted by the air pressure adjusting means is used as a counter pressure for the valve. When the valve is displaced by the hydraulic pressure against the counter pressure, It is characterized in that the pressure circuit is opened.

[Action]

If the air pressure of the air circuit is changed by the air pressure adjusting means in order to adjust the cushioning force, the magnitude of the counter pressure acting on the valve also changes, so that the hydraulic pressure required to displace the valve against this counter pressure. The opening of the hydraulic circuit by the valve is performed when the hydraulic pressure from the cylinder reaches a size corresponding to the cushion force, which realizes automatic adjustment of the damper force with respect to the cushion force. It will be.

〔Example〕

An upper limit damper device 1 according to an embodiment of the present invention is shown in FIG. In the following description, the same members and devices as those described in FIG. 2 are designated by the same reference numerals, and the description thereof will be simplified or omitted.

On the upstream side of the tank 20, the air circuit 21 is provided with a regulator 2 which is an air pressure adjusting means. Further, the inside of the cylinder portion 26 in the oil case 23 and the oil sump portion 23A are connected by the hydraulic circuit 3, and oil circulation is performed.

The hydraulic circuit 3 is provided with a valve 4 and a tank 5, and the valve 4 is for opening and closing the hydraulic circuit 3. The valve 4 is composed of a valve portion 4A and a pressure receiving portion 4B, and the valve portion 4A is slidable in the cylindrical portion 6A of the case 6 of the valve 4. This cylindrical part 6A
A port 7 connected to the inside of the cylindrical portion 26 is formed on the tip end surface of the, and a port 8 connected to the tank 5 is formed on the side surface of the cylindrical portion 6A. When the valve 4 moves, the ports 7 and 8 communicate with each other and are blocked by the valve portion 4A.

A circuit 9 branches off from the air circuit 21 on the downstream side of the regulator 2, and the circuit 9 is connected to the back pressure chamber 6B of the case 6 in which the pressure receiving portion 4B of the valve 4 is arranged. As a result, the air pressure of the air circuit 21 adjusted by the regulator 2 acts on the pressure receiving portion 4B, and this air pressure becomes a counter pressure for the hydraulic pressure from the inside of the tubular portion 26 acting on the valve portion 4A.

Next, the operation will be described.

As described above, the blank 34 is pressed by the upper die 32 and the lower die 33 while the wrinkle is prevented from being generated in the flange portion 34A by the cushioning force of the pneumatic die cushion device 10, and after the slide 31 reaches the bottom dead center. When it rises, the piston 25 also rises together with the cushion pad 16 and the like. When the piston 25 begins to be fitted into the tubular portion 26, the oil inside the tubular portion 26 is compressed,
The resulting hydraulic pressure acts on the valve portion 4A of the valve 4 via the port 7. While this oil pressure is low, the valve 4 has reached the limit of rightward movement in Fig. 1 due to the counter pressure.
It is cut off during 8 and the hydraulic circuit 3 is closed. When the hydraulic pressure increases as the piston 25 is fitted into the tubular portion 26, the valve 4 moves backward while compressing the air in the back pressure chamber 6B, but when the hydraulic pressure is smaller than the air pressure as the counter pressure, the ports 7 and 8 are Can't reach communication. Between the above,
The damper device 1 will generate a damper force. When the piston 25 is deeply inserted into the tubular portion 26, the hydraulic pressure increases, so that the ports 4 and 7 communicate with each other and the hydraulic circuit 3 opens by retracting the valve 4.

Here, when the air pressure in the air circuit 21 is reduced to a low pressure by the regulator 2 in order to reduce the cushioning force of the die cushion device 10, the counter pressure acting on the valve 4 is also reduced, so that the valve 4 has a valve portion. While the hydraulic pressure from the cylinder portion 26 acting on 4A is small, the hydraulic circuit 3 is retracted to open and the damper force of the damper 1 becomes small. Further, when the air pressure of the air circuit 21 is made high by the regulator 2 in order to increase the cushioning force of the die cushion device 10, the counter pressure of the valve 4 also becomes high, so that the valve 4 has a hydraulic pressure acting on the valve portion 4. The hydraulic circuit 3 does not retreat to the open position until it becomes large, and in this case, the damper force of the damper device 1 becomes large.

As described above, according to the damper device 1 according to the present embodiment, when the cushion force of the die cushion device 10 is adjusted, the damper force of the damper device 1 changes according to the cushion force, and the throttle valve and the like are not adjusted. However, it will always be possible to automatically obtain an appropriate amount of damper force that corresponds to the cushion force. Further, this effect can be achieved by providing the hydraulic circuit 3 with a valve 4 for opening and closing the hydraulic circuit, and causing the valve 4 to act on the adjusted air pressure of the air circuit 21 as a counter pressure. There is no need to change.

The pneumatic die cushion device 10 in the above embodiment
Although the type has only one cushion cylinder 15, the damper device according to the present invention can be applied to a pneumatic die cushion device having two or more cushion cylinders. The device according to the invention can be applied to a die cushion device of a type in which the cushion cylinder is fixed and the piston moves up and down. Further, the hydraulic circuit opening / closing valve is not limited to the one having the structure of the above-mentioned embodiment, and may be, for example, a rotary type valve. If necessary, the adjusted air pressure of the air circuit is a counter for the hydraulic pressure. Any type of valve may be used as long as it acts as a pressure and hydraulically displaces against the counter pressure to open the hydraulic circuit.

Further, although the damper device of the above-described embodiment is for a die cushion device for blank wrinkle pressing, the present invention is also applicable to a damper device for a knockout or ejector die cushion device. .

[Effect of device]

According to the present invention, when the cushion force of the die cushion device is adjusted, the damper force can be automatically changed according to the cushion force without adjusting the throttle valve or the like. Since it corresponds to the cushioning force, the shock can be appropriately mitigated when the die cushion device returns to the upper limit.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a die cushion device to which a damper device according to an embodiment of the present invention is attached, and FIG. 2 is a view similar to FIG. 1 showing a conventional damper device. 1 ... Upper limit damper device, 2 ... Regulator as air pressure adjusting means, 3 ... Hydraulic circuit, 4 ... Valve, 10 ...
Pneumatic die cushion device, 15 …… cushion cylinder, 16 …… cushion pad, 17 …… cushion pin,
19 …… Blank holder, 21 …… Air circuit, 23 …… Oil case, 23A …… Oil sump, 24 …… Piston rod, 25 ……
Piston, 26 …… Cylinder part, 32 …… Upper mold, 33 …… Lower mold.

Claims (1)

[Scope of utility model registration request] 1. A damper device provided in a pneumatic die cushion device for generating a cushioning force by compressing air in a cushion cylinder, the piston device moving up and down in an oil sump portion together with a cushion pad of the die cushion device, In an upper limit damper device configured to include a tubular portion that is fitted when the piston rises and a hydraulic circuit connected to the tubular portion, a hydraulic circuit opening / closing in which hydraulic pressure from the tubular portion acts on the hydraulic circuit. And an air pressure adjusting means is provided in an air circuit for supplying air to the cushion cylinder, and the air pressure of the air circuit adjusted by the air pressure adjusting means is caused to act on the valve as a counter pressure. The hydraulic circuit is opened by the displacement of the valve by the hydraulic pressure against the counter pressure. Upper damper pneumatic die cushion apparatus characterized by.