JPH01273631A - Press die - Google Patents

Abstract

PURPOSE:To facilitate working with a decreased quantity of deformation with high accuracy without lowering productivity by sticking a deformation resistor which generates deformation resistance by deformation to the forming face of at least one die of the upper and lower dies. CONSTITUTION:A thin sheet-like work 39 is disposed on a binder plate 23 and a die 15 of the upper die is lowered. The work 39 which is held pinched between the die 15 and tapered parts 35 and 37 of the pressing plate 23 is pressed onto a punch 19 of the lower die. The work 39 is buldged between the hollow curved forming face 17 on the die side and the projecting curved forming face 21 on the punch side, by which the product having the prescribed curved shape is obtd. The deformation resistor 43 consisting of natural rubber, etc., is previously stuck to the above-mentioned forming face 21 of the above-mentioned press die. This resistor 43 is deformed to the prescribed extent by the pressing force and the work 39 is uniformly pressed to the die side forming face 17 by the deformation resistance force thereof, by which the work is formed to the curved shape having high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a press mold, and particularly to a press mold suitable for press forming a thin plate-like workpiece.

[Conventional technology]

Conventionally, a product 2 having a curved surface 1 shape as shown in FIG. 2 has been molded using an ordinary mold using a rigid punch and a die.

However, in the curved surface forming process of thin plates where the amount of deformation of the workpiece is small, such as Product 2 shown in the figure, there is a problem in that it is difficult to obtain good shape accuracy that follows the shape of the punch and die. .

This is mainly caused by uneven thickness of the workpiece, uneven thickness due to differences in elongation during forming, fluctuations in the bottom dead center position of the press slide, and variations in springback and its amount. This is caused by

In order to solve these problems, conventional methods include a method that allows for springback in the punch and die shapes in advance, and a hydroform method that uses hydraulic pressure to form the mold.

Hydromatic method, natural rubber, synthetic rubber,
Various methods have been used, such as the Gehring method, the Marhome method, and the Wheelon method, in which polyurethane rubber or the like is molded using a punch or die.

[Problems to be Solved by the Invention] However, with the above-mentioned method in which the amount of springback is estimated in advance in the shape of the punch and die, the shape may collapse due to factors such as changes in the bottom dead center of the press slide or uneven plate thickness. In addition, there is a problem in that it is not possible to adequately respond to changes in the amount of springback.

In addition, the hydroform method uses liquid pressure to form the mold.

In the hydromatic method, in order to prevent wrinkles from forming on the workpiece, it is necessary to use a hydraulic pump to maintain high hydraulic pressure during the initial stage of forming, while also protecting the seal membrane. Therefore, it is necessary to return the liquid pressure to a low pressure after molding is completed, resulting in a long molding cycle and low productivity.

Furthermore, in methods such as the Gehring method, Marhome method, and Wheelon method, which use punches or dies to mold natural rubber, synthetic rubber, polyurethane rubber, etc., it is difficult to obtain uniform pressure on the molding surface, and it is difficult to control the pressure. Furthermore, since the deformation rate of the elastic body such as rubber increases, there is a problem that durability is lacking and the life span is shortened.

The present invention solves the above-mentioned problems, and aims to provide a press mold that can easily perform highly accurate processing without reducing productivity.

[Means to solve the problem]

The press mold of the present invention holds a thin plate-shaped workpiece placed between a pair of molds by relatively moving the pair of molds toward opposing surfaces and pressing it from both sides. In a press mold for forming a shape, a deformation resistor that generates a deformation resistance force by deformation is fixed to the molding surface of at least one of the pair of molds.

[Function] In the press mold of the present invention, when a pair of molds approaches each other by a predetermined distance or more, the deformation resistor fixed to the molding surface of at least one of the molds deforms, and this deformation causes the slide Fluctuations in the bottom dead center position of the machine and variations in the thickness of the workpiece are absorbed.

[Example] Hereinafter, an example will be described in which details of the present invention are shown in the drawings.

FIG. 1 shows an embodiment of a press mold of the present invention, and in the figure, reference numeral 11 indicates an upper mold mounting plate fixed to a slide 13 of the press.

A molding die 15 is fixed to the lower surface of the upper die mounting plate 11, and a die-side molding surface 17 consisting of a concave curved surface with a relatively large radius of curvature is formed on the lower surface of this die 15. .

A punch 19 is disposed below the die 15, and a punch-side forming surface 21 consisting of a convex curved surface having a shape corresponding to the die-side forming surface 17 is formed on the upper surface of the punch 19.

This punch 19 is inserted into the holding plate 23 in a fitted state and is fixed to the upper surface of the lower die mounting plate 25. Further, the lower die mounting plate 25 is fixed to a bolster 27 of the press.

A cushion pin 31 is inserted through the lower die mounting plate 25, and a presser plate 23 is fixed to the upper end of the cushion pin 31.

A tapered portion 37 having a shape corresponding to the tapered portion 35 formed at the lower part of the die 15 is formed on the upper inner periphery of the holding plate 23, and a tapered portion 37 having a shape corresponding to the tapered portion 35 formed at the lower part of the die 15 is formed on the upper surface of the holding plate 23. A pilot 41 for positioning is fixed.

In this embodiment, a deformation resistor 43 is fixed to the punch-side molding surface 21 of the punch 19, which generates a deformation resistance force through deformation.

The deformation resistor 43 is made of a semi-soft material or an elastic material such as natural rubber or polyurethane rubber, and in this embodiment, the deformation resistor 43 is
1 by coating.

In the press die configured as described above, first, the workpiece 39 is placed into the holding plate 23'' while being positioned by the biront 41.

After this, the die 15 is lowered by the slide 13 of the press.
is lowered, and the outer periphery of the workpiece 39 is held between the tapered parts 35 and 37. That is, the workpiece 39 is
Although the pressure plate 23 is held between the press plate 23 and the press plate 23, the pressure of the dictation of the press adjusted to an appropriate pressure is acting on the cushion pin 31 that supports the press plate 23.
The portion of the workpiece 39 held between the die 15 and the holding plate 23 is in a state in which sliding is restricted.

In this state, the workpiece 39 is
It comes into contact with the apex of 9, and the forming process by stretch forming is started.

Thereafter, the slide 13 is further lowered, and the workpiece 39 is formed by the die 15 and punch 19.

Note that at this time, the workpiece 39 is securely held between the die 15 and the presser plate 23, so that sliding is regulated and the forming process by stretch forming is performed reliably.

Thereafter, as the slide 13 further descends and approaches the bottom dead center as shown on the right side of FIG. The upper and lower surfaces of 39 are in close contact with each other, and the deformation resistor 43 is pressed downward by the die 15. This pressing force deforms the deformation resistor 43 by a predetermined amount, and the deformation resistance force at this time causes the workpiece 39 to be shaped. Die-side molding surface 17 of the highly accurate die 15
is pressed evenly.

However, in the press mold configured as above,
Since the deformation resistor 43 that generates deformation resistance force through deformation is fixed to the punch side molding surface 21 of the punch 19, the die 15
When the punch 19 and the punch 19 approach each other by a predetermined distance or more, the punch 19
The deformation resistor 43 fixed to the punch-side forming surface 21 of the punch side is deformed, and this deformation absorbs fluctuations in the bottom dead center position of the slide 13 and fluctuations in the plate thickness of the workpiece 39, thereby improving accuracy. It becomes possible to perform high-quality processing easily.

In addition, in the press mold configured as described above, the die 15 and the punch 19 are configured almost the same as a normal sheet metal mold, so that high productivity can be achieved like the conventional sheet metal mold. You can get sex.

In the embodiments described above, the deformable resistor 43 is arranged on the punch 19 side, but the present invention is not limited to such an embodiment. For example, the deformable resistor 43 is arranged on the die 15 side. Of course, it may be arranged.

Further, in the embodiments described above, an example was described in which the deformation resistor 43 was fixed to the die-side molding surface 21 by coating, but the present invention is not limited to such embodiments. Of course, it may also be fixed.

[Effects of the Invention] As described above, in the press mold of the present invention, a deformation resistor that generates deformation resistance force by deformation is fixed to the molding surface of at least one of the pair of molds. There is an advantage that highly accurate machining can be easily performed without reducing productivity.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of a press mold of the present invention. FIG. 2 is a longitudinal sectional view showing a product formed by press working. [Explanation of symbols of main parts] 15...Die 19...Punch 39...Workpiece 43...Deformation resistor.

Claims (1)

[Claims] (1) For presses that mold a thin plate-shaped workpiece placed between a pair of molds into a predetermined shape by moving the pair of molds toward opposing surfaces and pressing from both sides. A press mold, characterized in that a deformation resistor that generates a deformation resistance force by deformation is fixed to the molding surface of at least one of the pair of molds.