JPH1177178A - Press mold - Google Patents

Abstract

(57) [Problem] To provide a press die having an inner cushion for holding wrinkles on the inside of a punch in order to draw and form a work having a door or window cutout like a side panel of an automobile, Conventionally, since the inner cushion is elastically supported by the gas cylinder, when the upper die is raised after drawing, there is a problem that the inner cushion also rises and the work floats from the punch. In view of the above, an object of the present invention is to provide a press die in which a work is not lifted from a punch by holding an inner punch on a drawing side. An inner cushion (2) is elastically supported by a die cushion cylinder (21), and the operation of the die cushion cylinder (21) is controlled by a hydraulic unit (U). It is configured to hold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press die for drawing, for example, a side panel of an automobile, which has a wrinkle press inside a punch.

[0002]

2. Description of the Related Art In recent years, the integration of pressed parts of automobiles has been advanced, and as a result, for example, as shown in FIG.
May be formed by pressing.
As shown in FIG. 3, an outer cushion 5 for pressing wrinkles on the outer periphery of the work W and an inner cushion 2 for holding wrinkles around the punched portion N are provided. Conventionally,
In the press die 1 of this type, the outer cushion 5 is supported by cushion pins 3 to 3 on the press machine side P, and the inner cushion 2 is supported by gas cylinders 4 to 4. Note that, in FIG. 2, a range where wrinkles are pressed during drawing is shown with hatching.

[0003]

As described above, in the conventional press die 1, in addition to the machine side cushion pins 3 to 3 for the outer cushion 5, the gas cylinders 4 to 4 for the inner cushion 2 are provided. It was configured to be used together. However, the machine-side cushion pins 3 to 3 can be locked on the retracted side, but the gas cylinders 4 to 4 cannot be locked on the retracted side, so that the machine-side cushion pins 3 to 3 are unavoidably locked on the retracted side. After drawing, the outer cushion 5 and the inner cushion 2 are both raised as the upper die 6 is raised. The inner and outer cushions 2,
In No. 5, since the stroke is determined by the molding depth of each part, it is actually impossible to synchronize using the machine-side cushion pins 3 to 3.

As a result, as shown in FIG. 4, the work W is lifted by the inner and outer cushions 2 and 5 and lifted off the punch 7 as the upper die 6 is raised. As a result, the following various problems occur. Was. First, the upper surface of the work W and the punch 7 becomes negative pressure due to the momentum of lifting when the upper die 6 is lifted, and the work W undulates greatly up and down. As a result, there is a problem that air distortion occurs in the work W.

After the upper die 6 is lifted, the work W is received by the inner and outer cushions 2 and 5, but is lifted from the punch 7, so that the work W is transferred by the vacuum transfer machine 8. In such a case, there is a problem that a part of the work W is pushed downward and is distorted during chucking by the vacuum pads 8a to 8a.

Further, in order to reduce the above-mentioned problems as much as possible, the opening speed of the upper mold 6 must be reduced,
Since the pressing speed of the vacuum pads 8a to 8a is reduced, there is a problem that the cycle time is deteriorated and the production efficiency is not good.

Further, since the gas cylinders 4 to 4 cannot be locked on the retracted side, only the inner cushion 2 is in a state of being raised even when storing the mold. For this reason, a gap is generated between the upper mold 6 and the outer cushion 5 and the punch 7, so that foreign matter such as dust easily enters the mold, resulting in a problem that the mold is worn.

The present invention has been made by focusing on the fact that the above-mentioned various problems are caused by the inability to lock the inner cushion on the retracted side. The inner cushion inside the punch is locked on the retracted side similarly to the outer cushion. It is intended to provide a press die that can be used.

[0009]

According to the present invention, there is provided a press die for drawing which has an inner cushion for holding wrinkles inside a punch, wherein the inner cushion is a die cushion cylinder. , So that the supply of the pressure oil to the die cushion cylinder is shut off and the inner cushion can be held at the retracted side.

According to this press die, the inner cushion can be locked to the retracting side by shutting off the supply of the pressure oil to the die cushion cylinder. Therefore, after the drawing, the inner cushion is retracted when the upper die rises. The upper die can be raised without lifting the drawn work from the punch.

Since the work does not rise from the punch even when the upper mold is raised, the work does not move up and down as in the prior art, and thus no air distortion occurs. Further, since the vacuum pad can be pressed against the work placed on the punch, the work is not distorted at the time of the conventional vacuum transfer.

As described above, since the work is not distorted when the upper mold is raised and when the vacuum is conveyed, the operating speed of each part such as the upper mold rising speed and the pressing speed of the vacuum pad can be greatly increased. As a result, the cycle time can be reduced and the production efficiency can be greatly improved.

Further, if the supply of pressure oil to the die cushion cylinder is shut off, the inner cushion is held on the retracted side, so that the upper mold is completely adhered to the punch and the inner and outer cushions during storage of the mold. Therefore, it is possible to completely prevent foreign matter from entering the mold, and to reduce wear of the mold.

According to a second aspect of the present invention, there is provided the press die according to the first aspect, wherein the supply of the pressurized oil to the die cushion cylinder includes the steps of: The hydraulic locking system includes a hydraulic hose connected to the protruding side of the cylinder and a locking valve that shuts off the supply of pressure oil to the die cushion cylinder through the hydraulic hose.

According to this press die, the inner cushion can be held at the retracted side by using the hydraulic locking system usually used on the press machine side, and the above-described operation and effect can be obtained with less cost. .

[0016]

Next, an embodiment of the present invention will be described with reference to FIG. In the present embodiment, a description of a configuration that does not particularly require a change is omitted, and the same reference numerals are used. Also, a press machine to which a press die 10 described below is attached does not require any particular change, and is not shown.

The inner cushion 2 arranged inside the punch 7 is elastically supported by a plurality of die cushion cylinders 21 to 21 provided on the cushion plate 20. In this cushion plate 20, each die cushion cylinder 21 has a protruding side (head side) communicating with an oil passage 21a. When the pressurized oil is supplied to the protruding side via the oil passage 21a, the die cushion cylinder 21 operates to the protruding side, whereby the inner cushion 2 is moved.
Rises. On the other hand, when a load is applied to the die cushion cylinder 21 due to the clamping force of the upper die 6 or the own weight of the inner cushion 2, the die cushion cylinder 21 moves to the retraction side while discharging the pressure oil on the protruding side to the oil passage 21a. Will be returned. In addition, each die cushion cylinder 21-21
Are all in communication with the oil passage 21a, and therefore simultaneously operate in the same direction.

Two hydraulic hoses 2 are provided in the oil passage 21a.
2, 23 are connected. Both hydraulic hoses 22 and 23 are connected to a hydraulic unit U. The hydraulic hose 22 is a hose on the pressure oil supply side, and enters the hydraulic tank 26 via the relief valve 24 of the hydraulic unit U. On the other hand, the hydraulic hose 23 is a hose on the pressure oil return side, and similarly enters the hydraulic tank 26 via the locking valve 25 of the hydraulic unit U. Both hydraulic hoses 22 and 2
3, the portion that has entered the hydraulic tank 26 is 22 in the figure.
a and 23a.

A predetermined amount of oil is stored in the hydraulic tank 26. An air hose 28 is connected to an upper portion of the hydraulic tank 26, and compressed air is supplied into the hydraulic tank 26 via the air hose 28, and the compressed air acts on an oil level in the hydraulic tank 26. A hydraulic locking system for the die cushion cylinders 21 to 21 is constituted mainly by the hydraulic unit U.

According to the press die 10 of the present embodiment configured as described above, the drawing of the work W is performed as follows. As shown by the two-dot chain line in the figure, at the stage of setting the work W, the inner and outer cushions 2 and 5 are both located at the raised position. The outer cushion 5 is held at the raised position by the operation of the cushion pins 3 to 3 of the press machine side P to the protruding side, and the inner cushion 2 is raised by the operation of the die cushion cylinders 21 to 21 to the protruding side. Held in position.

The projecting sides of the die cushion cylinders 21 to 21 are operated by opening the relief valve 24 and closing the locking valve 25 in the hydraulic unit U, so that the hydraulic cylinder U can be moved into the hydraulic tank 26 through the hydraulic hose 22 on the hydraulic oil supply side. Is supplied to the oil passage 21a and thus to the projecting side of the die cushion cylinder 21. The supply of the pressure oil is performed by the air pressure acting on the oil level in the hydraulic tank 26.

After setting the work W, the upper die 6 is moved down to form the work W by drawing. Both cushions 2 and 5 descend from the position on the protruding side shown by the two-dot chain line to the position on the retraction side shown by the solid line while being pressed by the upper mold 6 via the work W. At this stage of drawing,
While the relief valve 24 is closed and the supply of the pressure oil is stopped, the locking valve 25 is opened and the pressure oil supplied to the cushion plate 20 is supplied through the hydraulic hose 23 and the locking valve 25 on the pressure oil return side to the hydraulic pressure. It is returned into the tank 26.

After the drawing is performed, the locking valve 25 is also closed when the upper die 6 moves up, thereby locking the pressure oil in the cushion plate 20 (the state in which the pressure oil is neither supplied nor discharged). ). For this reason, the die cushion cylinders 21 to 21 and thus the inner cushion 2 are held on the retracted side indicated by the solid line in the figure even when the upper die 6 is raised. The outer cushion 5 is also locked by locking the cushion pins 3 to 3 on the machine side P to the retracted side.
It is held on the retracted side shown by the solid line in the figure. Therefore, even when the upper die 6 is raised, the work W is not lifted from the punch 7 as in the related art, and is held at the position where the drawing is performed.

After the upper die 6 is returned to the upper end position, the vacuum transfer device is set above the work W, and thereafter,
The vacuum pads 8a to 8a are pressed against the work W and chucked. At this time, since the work W is received by the punch 7, there is no distortion as in the related art.

When the transfer of the work W by the vacuum transfer device 8 is completed, the relief valve 24 of the hydraulic locking system is opened, whereby the pressure oil is again supplied to the cushion plate 20 side, and each of the die cushion cylinders 21 to 21 is moved to the protruding side, so that the inner cushion 2 is returned to the protruding side shown by a two-dot chain line in the figure.
At the same time, the lock of the cushion pins 3 to 3 on the machine side P is also released, and the outer cushion 5 is returned to the protruding side also indicated by the two-dot chain line. Thus, one cycle of drawing by the press machine is completed. I do.

According to the press die 10 constructed as described above, even after the upper die 6 is raised after the drawing, the inner cushion 2 and the outer cushion 5 are held as they are on the drawing side. Is held at the drawn position without being lifted from the punch 7.
For this reason, the work W does not undulate up and down unlike the related art, and therefore, no air distortion of the work W occurs.

The work W placed on the punch 7
, The vacuum pad 8a to 8a can be pressed against the workpiece W, so that the work W is not distorted at the time of the conventional vacuum conveyance.

As described above, since the work W is not distorted when the upper die 6 is raised and when the vacuum conveyance is performed, the operating speed of each part such as the rising speed of the upper die 6 and the pressing speed of the vacuum pads 8a to 8a is greatly reduced. It is possible to increase the speed, thereby shortening the cycle time of the press machine and greatly improving the production efficiency.

When the press die 10 is removed from the press machine and stored, the pressurized oil is drained from the cushion plate 20.
21 are held on the retracted side by the weight of the inner cushion 2, and the inner cushion 2 is held on the retracted side. Further, the outer cushion 5 is also detached from the cushion pins 3 to 3 on the machine side P, so that the outer cushion 5 is held on the retracted side by its own weight. As described above, since the inner and outer cushions 2 and 5 are held on the retracted side with respect to the punch 7 during the storage of the mold, the upper mold 6 can be kept in close contact with the punch 7, and as a result, Foreign matter can be prevented from entering the inside, and the wear can be reduced.

Lastly, the hydraulic locking system of the illustrated form is generally provided with the cushion pins 3 to 3 on the press machine side P.
It is used as a system to lock on the retracted side, but by applying this as a unique locking system of the press type, it is possible to obtain the above-described various effects at a lower cost. The press die according to the present invention has a great feature.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a plan view of a work.

FIG. 3 is a longitudinal sectional view of a conventional press die.

FIG. 4 is a side view showing a state where an upper die is raised after drawing by a conventional press die. In this figure, a state is shown in which the inner cushion is located on the protruding side with respect to the punch, so that the work floats from the punch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conventional press mold 2 ... Inner cushion 3 ... Cushion pin on press machine side 4 ... Gas cylinder 5 ... Outer cushion 6 ... Upper mold 7 ... Punch 8 ... Vacuum transfer machine 10 ... Press mold 21 of this embodiment 21 ... Die cushion Cylinder 24 ... Relief valve 25 ... Locking valve 26 ... Hydraulic tank 28 ... Air hose U ... Hydraulic unit W ... Work N ... Punching part

Claims (2)

[Claims] 1. A press die for drawing having an inner cushion for holding wrinkles inside a punch, wherein the inner cushion is elastically supported by a die cushion cylinder, and the supply of pressure oil to the die cushion cylinder is shut off. A press die, wherein the inner cushion can be held at the retracted side. 2. The press die according to claim 1, wherein the supply of the pressurized oil to the die cushion cylinder is connected to a hydraulic tank in which an air pressure is applied to an oil level and to a projecting side of the die cushion cylinder from the hydraulic tank. A press-type die, comprising a hydraulic locking system including a hydraulic hose and a locking valve for shutting off supply of pressurized oil to the die cushion cylinder via the hydraulic hose.