JPH01273626A - Press die - Google Patents

Abstract

PURPOSE:To enable working with high accuracy disposing a liquid pressure forming mechanism which presses a work by a liquid pressure when the other wide approaches one die of a pair of dies by a prescribed distance or longer. CONSTITUTION:The work 39 is positioned by a pilot 41 and is charged onto a binder plate 33. A slide 13 is lowered to lower the die 15 and to pinch the outside circumference of the work 39 between tapered parts 35 and 37. The slide 13 descends further and the work is formed by the die 15 and a punch 19. The punch 19 is pressed downward by the work 39 when the slide 13 descends further and approaches near to the bottom dead point. A high pressure is then acted on the liquid in a liquid pressure chamber 45 and the liquid in a communicating passage 47 is pressurized to a high pressure. This liquid presses the rear part of a sheet member 43 uniformly. The final forming by liquid pressure forming is thus executed. The punch 19 is moved in follow up to the die 15 by the energizing force of an energizing mechanism 55 and the liquid pressure is released when the slide 13 rises beyond the bottom dead point. The work 39 is thereby subjected to the liquid pressure forming without being affected by the press accuracy and plate thickness and, therefore, the high- accuracy working is executed.

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.

[Problem to be solved by the invention]

However, with the above-mentioned method in which the amount of springback is assumed in advance for the shape of the punch and gouer, the shape may collapse due to factors such as positional fluctuation of the bottom dead center of the press slide or unevenness of the plate thickness. The problem is that they cannot adequately respond to change.

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 increase the liquid pressure to high pressure during the initial stage of forming. In order to protect the product, 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 according to the first aspect of the present invention presses a thin plate-shaped workpiece placed between the pair of molds by moving the pair of molds relatively toward opposing surfaces and pressing the workpiece from both sides. In a press mold for forming into a predetermined shape, a liquid that presses the workpiece by hydraulic pressure when the pair of molds approaches one of the molds by a predetermined distance or more. It is equipped with a pressure forming mechanism.

A press mold according to a second aspect of the invention includes a sheet member that liquid-tightly covers a molding surface of the mold, a cylinder block that accommodates the mold, and a cylinder block that accommodates the mold. It is composed of a hydraulic pressure chamber formed between the opposite side surface of the molding surface and the cylinder block, and a communication passage communicating this hydraulic pressure chamber with the back surface of the sheet member.

[Function] In the press mold of claim 1, when the pair of molds approaches each other by a predetermined distance or more, the hydraulic forming mechanism disposed in at least one of the molds is activated, and the workpiece is pressed by hydraulic pressure. The final molding is then carried out.

In addition, in the press mold of claim 2, when the pair of molds approaches each other by a predetermined distance or more, high pressure acts on the hydraulic chamber formed between the cylinder block and the opposite side of the molding surface of the mold,
Due to this pressure, the liquid in the communication path communicating with the hydraulic pressure chamber becomes high pressure, and the back surface of the sheet member is pressed, and the workpiece is pressed by this sheet member, thereby performing final shaping.

[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 die of the present invention, and in the figure, reference numeral 11 indicates an upper die 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. 9 A punch 19 is disposed below the die 15, and on the upper surface of the punch 19, a punch side forming surface 21 consisting of a convex curved surface having a shape corresponding to the goo side forming surface 17 is formed.

This punch I9 is inserted with its lower part fitted into a cylinder block 23, and the cylinder block 23 is fixed to the upper surface of a bolster 25 of the press.

On the top surface of the cylinder block 23, the cylinder block 2
A plate 29 having a through hole 27 with a smaller diameter than the inner diameter of the plate 29 is fixed.

Penetrating the cylinder block 23 and plate 29,
A cushion pin 31 is inserted through the cushion pin 31, and a cylindrical pressing plate 33 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 33, 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 33. A pilot 41 for positioning is fixed.

In this embodiment, the punch 19 includes a die 15.
A hydraulic forming mechanism is arranged that presses the workpiece 39 with hydraulic pressure when the punch 19 approaches the workpiece 39 by a predetermined distance or more.

This hydraulic forming mechanism includes a forming surface 21 on the bunch side of the punch 19.
A sheet member 43 that liquid-tightly covers the punch 19, a cylinder block 23 that accommodates the punch 19, a hydraulic chamber 45 formed between the lower surface of the punch 19 and the cylinder block 23, and a sheet member 43 that covers the hydraulic chamber 45. A communication path 47 that communicates with the back side of
The main part is made up of.

That is, the punch-side molding surface 21 of the punch 19 is covered with a sheet member 43 made of, for example, rubber, and the outer periphery of the sheet member 43 is fixed to the outer periphery of the punch 19 in a fluid-tight manner by a presser ring 49. .

Further, the lower part of the punch 19 is inserted into the cylinder block 23 in a fitted state, and a sealing mechanism consisting of a backup ring 51 and a packing 53 is arranged in this insertion portion.

Between the lower surface of the punch 19 and the cylinder block 23,
For example, a hydraulic chamber 45 is formed in which a liquid such as oil is accommodated.

A large number of through holes are formed in the vertical direction in the punch 19, and these through holes serve as a communication path 47 that communicates the hydraulic chamber 45 with the back surface of the sheet member 43.

Further, a biasing mechanism 55 made of a spring that biases the punch 19 upward is arranged between the lower surface of the punch 19 and the cylinder block 23, and the elastic force of this biasing mechanism 55 is It is set to a value greater than the forming force of the material 39.

Further, the cylinder block 23 is formed with a through hole 57 that opens into the hydraulic pressure chamber 45, and the other end of the vibro 1, which has one end connected to the hydraulic pressure generation source 59, is connected to the through hole 57. There is. Further, a check valve 63 is arranged in the vibro 1.

In the press die configured as described above, the forming process is performed by stretch molding in the initial stage of molding, and the molding process is performed by hydraulic forming in the final stage of molding.

That is, first, the workpiece 39 is placed onto the holding plate 33 while being positioned by the pilot 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 portions 35 and 37. That is, the workpiece 39, the die 15
The pressure of the dictation of the press, which is adjusted to an appropriate pressure, is acting on the cushion pin 31 that supports the presser plate 33.
The portion of the workpiece 39 held between the die 15 and the holding plate 33 is in a state in which sliding is restricted.

In this state, the workpiece 39 is
It comes into contact with the apex of the sheet member 43 of No. 9.

After this, the slide 13 further descends and the workpiece 39 is formed, but the elastic force of the biasing mechanism 55 that urges the punch 19 upward reaches a value greater than the forming force of the workpiece 39. Since the punch 19 is set as shown in FIG. 1, the punch 19 maintains the state on the left side in FIG.
The workpiece 39 is formed by the following steps.

Note that at this time, the workpiece 39 is securely held between the die 15 and the pressing plate 33, so that sliding is regulated and the forming process is performed by stretch forming.

Thereafter, when the slide 13 further descends and approaches the bottom dead center, the punch 19 is pressed downward by the workpiece 39, and the punch 19 begins to move downward.

Due to this downward movement of the punch 19, high pressure acts on the liquid in the hydraulic pressure chamber 45, and due to this pressure, the liquid in the communication passage 47 communicating with the hydraulic pressure chamber 45 becomes high pressure, and the sheet member 43
The back surface of the sheet member 43 is pressed, and the workpiece 39 is pressed uniformly by the sheet member 43, and the final molding is performed by hydroforming.

Thereafter, when the slide 13 passes the bottom dead center and begins its upward movement, the punch 19 moves by following the die 15 for a predetermined distance due to the urging force of the urging mechanism 55, and the punch 19 moves within the hydraulic pressure chamber 45. The hydraulic pressure returns to the initial state, and the hydraulic pressure on the sheet member 43 is released.

In the press die configured as described above, the punch 19
In addition, a hydraulic forming mechanism is installed that presses the workpiece 39 with hydraulic pressure when the punch 19 and the die 15 approach each other by a predetermined distance or more, so that the final forming of the workpiece 39 is controlled by the precision of the press and the workpiece. Since this is carried out by hydraulic forming which is relatively unaffected by variations in the thickness of the material 39, highly accurate processing can be easily achieved.

Further, in the press mold configured as described above, the hydraulic forming mechanism includes a sheet member 43 that liquid-tightly covers the punch-side forming surface 21 of the punch 19, a cylinder block 23 that accommodates the punch 19, and a punch-side forming surface 21 of the punch 19. A hydraulic chamber 45 formed between the lower surface of 19 and the cylinder block 23;
and a communication path 47 that communicates with the back surface of the sheet member 43, it is possible to construct a hydroforming mechanism with a simple configuration.

Furthermore, in the press die configured as described above, the hydraulic pressure acting on the sheet member 43 changes in an optimal state in synchronization with the movement of the slide 13. There is no need to separately install a special mechanism, and thereby high productivity can be obtained.

In addition, in the embodiment described above, an example was described in which a hydraulic forming mechanism was arranged on the punch 19 side, but the present invention is not limited to such an embodiment. For example, a hydraulic forming mechanism was arranged on the die 15 side. Of course, it is also possible to arrange .

〔Effect of the invention〕

As described above, in the press mold of claim 1, when the pair of molds approaches one of the molds by a predetermined distance or more, the workpiece is pressed by hydraulic pressure. A hydraulic forming mechanism has been installed to prevent productivity from decreasing (
This method has the advantage of easily enabling highly accurate machining.

In addition, in the press mold of claim 2, the hydraulic forming mechanism of claim 1 is provided with a sheet member that liquid-tightly covers the molding surface of the mold, a cylinder block that accommodates the mold, and a molding surface of the mold. a hydraulic chamber formed between the opposite side of the cylinder block and the cylinder block;
Since this hydraulic pressure chamber is constituted by a communication passage communicating with the back surface of the sheet member, there is an advantage that the hydraulic forming mechanism can be constructed easily.

[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 23... Cylinder block 39... Workpiece material 43... Sheet member 45... Hydraulic pressure chamber 47... Connection aisle.

Claims (2)

[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. In the mold, at least one of the pair of molds is provided with a hydraulic forming mechanism that presses the workpiece with hydraulic pressure when the pair of molds approaches a predetermined distance or more. A press mold for (2) The hydraulic forming mechanism includes a sheet member that liquid-tightly covers the molding surface of the mold, a cylinder block that accommodates the mold, and a side surface opposite to the molding surface of the mold and the cylinder block. The press mold according to claim 1, comprising: a hydraulic pressure chamber formed therein; and a communication path communicating the hydraulic pressure chamber with the back surface of the sheet member.