JPH0747192Y2 - Die cushion device for transfer press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a die cushion device provided in a transfer press.

[Conventional technology]

A die cushion device conventionally installed in a transfer press is constructed as shown in FIG. 3 and operates as follows.

That is, when the slide a descends along the curve A shown in FIG. 4 and comes into contact with the upper mold attached to the slide a to start molding, the die cushion pad e also moves to the first position via the die cushion pin d. It descends along the curve B shown in FIG.

When the slide a reaches the bottom dead center and the molding is completed,
The die cushion pad e is locked in that position by a locking mechanism (not shown), and only the slide a and the upper die b are raised. After that, when the locking is released and the die cushion reaches the upper limit position, the work holding means g such as a vacuum cup provided on the feed bar f sucks and holds the work c and conveys it to the next process.

When the die cushion pad e is not locked, the die cushion pad e also moves to the fourth position as the slide a rises.
Since it rises along the curve B'in the figure, after the die cushion pad e reaches the upper limit, the work c is sucked and held by the work holding means g such as a vacuum cup provided on the feed bar f and conveyed to the next step. ing.

[Problems to be solved by the device]

However, in the above-mentioned conventional die cushion device, if the work c is picked up at the pad upper limit position, it is difficult to adjust the timing, and thus it is difficult to increase the speed. If the work c is strongly attached to the lower mold h and cannot be picked up by the work holding means g, there is a problem that the work c is difficult to convey. Further, when the die cushion pad e is not locked, the above-mentioned problems do not occur, but the take-out position of the work c is high, so that the slide a and the feed bar f are likely to interfere with each other, and as a result, the shape of the die or the work c. There was a problem such as being restricted by.

This invention was made for the purpose of improving the above problems, and by adding a small lift function after locking,
An object of the present invention is to provide a die cushion device for a transfer press, which can smoothly convey a work.

[Means and Actions for Solving the Problems]

In order to achieve the above object, the present invention provides a die cushion device of a transfer press having a locking function of locking the die cushion pad in a lowered position, in a die cushion cylinder hydraulic circuit for giving a cushion operation to the die cushion pad. By adding a circuit that lifts a small amount after the pad is locked, the work firmly attached to the lower mold after molding is peeled off from the lower mold by the rise of the die cushion pad, and the work can be conveyed even by the work holding means with a small holding capacity. The present invention provides a die cushion device for a transfer press that enables the above.

〔Example〕

An embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. In FIG. 1, reference numeral 1 is a transfer press, in which a lower surface of a slide 4 is mounted above a lower mold 3 installed on a bolster 2. Has an upper die 5 that moves up and down together with the slide 4, and a work 6 is formed between the upper die 5 and the lower die 3, and the formed work 6 is provided on a feed bar 7. It is conveyed to the next process by the work holding means 8.

A die cushion pad 10 for elastically supporting a part of the lower die 3 via a cushion pin 9 is provided in the bed 1a below the bolster 2 and the die cushion pad 10 is moved upward by an air cylinder (not shown). Being energized. The bottom of the die cushion pad 10 is supported by a piston rod 11a protruding upward from the die cushion cylinder 11.

The die cushion cylinder 11 is composed of two-stage cylinders 11 ₁ and 11 ₂ each having a large diameter on the upper side and a small diameter on the lower side, and are mounted on the piston rod 11a in the respective cylinders 11 ₁ and 11 ₂ . Further, the pistons 11b and 11c are accommodated, and the large-diameter side piston 11b is internally provided with a check valve 12 that flows only from the pressure chamber 11e side to the pressure chamber 11d side.

In the pressure chamber 11d, an oil tank 14 is
The oil inside is supplied through the servo valve 15 and the conduit 16, and the pressure chamber 11e is supplied from the conduit 16 through the logic valve 17 and the logic valve 18, and the pressure chamber 11f is supplied.
Is connected to an oil tank 14 via a servo valve 19 and a hydraulic pump 13.

On the other hand, the upstream side of the logic valve 18 that communicates with the pressure chamber 11e is connected to the hydraulic chamber 20a side of the hydraulic / pneumatic cylinder 20 via a pipe line 21.

The hydraulic / pneumatic cylinder 20 has a small-diameter hydraulic chamber 20a and a large-diameter pneumatic chamber 20b, and pistons 20d and 20e connected to the respective chambers 20a and 20b by a piston rod 20c are housed. Air is supplied from the air tank 22 to the air pressure chamber 20b side.

A lift amount adjusting bolt 23 is screwed on the end plate 20f on the side of the pneumatic chamber 20b. By adjusting the retracted position of the pistons 20d and 20e with the lift amount adjusting bolt 23, a small lift of the die cushion 10 can be achieved. The quantity l can be adjusted. Next, the operation will be described. When the slide 4 starts descending from the top dead center and the upper die 5 comes into contact with the work 6 on the lower die 3, and when the forming of the work 6 is started, the die cushion is passed through the cushion pin 9. The pad 10 is pushed down and starts descending.

At this time, since the logic valves 17, 18 and 24 are closed, the oil in the pressure chamber 11e flows into the pressure chamber 11d via the check valve 12 as the die cushion pad 10 descends.

When the slide 4 reaches the bottom dead center and the molding is completed,
The die cushion pad 10 is locked in that position by the action of the check valve 12, but at this time, oil compression and the piston rod 11
Since the die cushion pad 10 slightly floats due to the elongation of a, in order to prevent this, the logic valve 24 is opened for a short time and a small amount of oil is sent to the pressure chamber 11d, so that the die cushion pad 10 is l'shown in FIG. Just pull down.

Then, while slide 4 is rising, first the logic valve
When 17 is opened and the hydraulic pressure in the hydraulic chamber 11d is made to flow into the hydraulic chamber 20a of the hydraulic chamber cylinder 20, the pistons 20d and 20e in the oil chamber cylinder 20 are brought into contact with the lift amount adjusting bolt 23 against the pneumatic pressure. Retreat until touched.

The lift amount adjusting bolt 23 is adjusted in advance to a stroke corresponding to the small lift amount l, and the hydraulic pressure of the pressure chamber 11d flows into the hydraulic chamber 20a, whereby the die cushion pad 1
0 is lifted by a small lift amount 1 as shown in FIG. 2, whereby the work 6 attached to the lower mold 3 is pushed up via the cushion pin 9 and, at the same time, the feed bar 7 reaching above the work 6 is lifted. It is sucked and held by the work holding means 8.

After that, the logic valve 18 is opened, so the hydraulic / pneumatic cylinder
Oil in 20 hydraulic chambers 20a together with oil in pressure chambers 11d pressure chambers 11e
And the die cushion pad 10 starts to rise,
The slide 4 is returned to the upper limit position almost at the same time when it reaches the top dead center, and the work 6 held by the work holding means 8 is conveyed to the next process by the feed operation of the feed bar 7.

By repeating the above operation, the work 6 is formed,
The molded work 6 can be conveyed to the next process smoothly.

[Effect of device]

As described in detail above, this invention locks the die cushion pad lowered along with the forming in the lowered position and then raises the small lift amount.Therefore, the finished work is firmly attached to the lower die. However, since it is pushed up by the die cushion pad through the cushion pin, it can be peeled off more reliably from the lower mold.

As a result, the work can be adsorbed and conveyed by a work holding means such as a vacuum cup, so that it is possible to eliminate the problem that the work is firmly attached to the lower mold and becomes difficult to convey as in the conventional case, and the work is low. Since the slide can be held and conveyed at a position, the slide does not interfere with the work conveying means, and accordingly, there is no restriction such that the slide cannot be conveyed due to the mold or the shape of the work. Further, since the work immediately after being peeled from the lower mold can be held and conveyed to the next processing station, the work can be conveyed at high speed, and thereby the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is an operation explanatory diagram, and FIGS. 3 and 4 are conventional explanatory diagrams. 10 is a die cushion pad, 11 is a die cushion cylinder, 11d is a pressure chamber, 18 is a logic valve, and 20 is a hydraulic / pneumatic cylinder.

Claims (3)

[Scope of utility model registration request] 1. A die cushion device of a transfer press having a locking function for locking the die cushion pad 10 in a lowered position, wherein the die cushion pad is used.
Die cushion cylinder 11 that gives 10 cushioning action
A die cushion device for a transfer press, wherein a circuit for lifting a small amount after locking the die cushion pad 10 is added to the hydraulic circuit of. 2. A die cushion cylinder 11 provided with the additional circuit.
2. The die cushion device according to claim 1, comprising a hydraulic / pneumatic cylinder 20 connected to the upper pressure chamber 11d of FIG. 1 through a logic valve 17, and an air source for supplying air to the hydraulic / pneumatic cylinder 20. 3. A die cushion device according to claim 1, wherein said hydraulic / pneumatic cylinder 20 is provided with lift amount adjusting means for setting a small lift amount.