JPH0243592Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a diaphragm seal structure for preventing pressure leakage at a diaphragm during pressurization in a rubber pad forming press.

The rubber pad forming press known from Japanese Patent Publication No. 44-25516 and Japanese Patent Publication No. 46-17758 is a rubber pad forming press that is suitable for machining multiple parts at the same time in small quantities, such as sheet metal pressing of aircraft body parts. It is used as a press machine. In a conventional rubber pad forming press of this type, a mold is placed in the cavity of a tray having a flat cavity with a funnel-shaped inner wall on the upper surface, and the mold is covered with the mold. After placing the processed metal plate, this tray is placed into a high-pressure cylindrical container fixedly placed horizontally, and inside the container, liquid is applied to the processed metal plate via a thick urethane-based pressure pad rubber. A diaphragm that expands under pressure is mounted, a support block divided into upper and lower halves that transmits the press reaction force to the inner wall surface of the container is mounted on the upper part of the diaphragm and the lower part of the tray, and after the openings at both ends of the container are closed, hydraulic pressure is applied to the diaphragm. By introducing the pressure pad rubber and filling the cavity space with fluid deformation, press molding using multiple molds is performed at once. The diaphragm is made of a material with high elongation and restoring force, such as neoprene, and is shaped like a large rectangular flat box measuring 1 m x 3.6 m.The diaphragm has a width of about 50 mm extending inwardly at the edge of its peripheral wall. An overhanging lip is formed and is mounted and sealed by applying the lip to the lower surface of the upper support block and tightening the lip between the inner fastener and the lower surface of the support block. However, in such a structure, since the pressure pad rubber in contact with the outside of the diaphragm is fluidly deformed during pressure molding, the periphery of the diaphragm is pulled outward by the deformation of the pad rubber, thereby tightening the lip of the diaphragm. The amount of contact with the lower surface of the support block at this point is too small, and there is a high risk that the diaphragm seal will break.

The present invention aims to provide a structure that ensures a secure seal at the diaphragm lip against deformation during pressure forming as described above. A circumferential groove is provided on the block surface to surround the diaphragm along the lip part, and by tightening the lip part between the fastening fitting and the support block, a part of the lip part, preferably a part near the outer periphery, is formed. The point is that it is fitted into this circumferential groove. According to the present invention, such a bite prevents the lip of the diaphragm from coming off from the fastening part even if it is stretched due to deformation of the pad rubber during pressure molding, and therefore prevents the lip from coming off the fastening part of the diaphragm. The abutment margin between the parts is also maintained sufficiently, and the seal is prevented from breaking.

To explain the present invention with reference to the drawings, FIG. 1 is a cross-sectional view of a rubber pad forming press according to the present invention, and FIG. 2 is an enlarged sectional view showing the main part of the diaphragm lip. In FIG. 1, 1 is a high-pressure cylindrical container, 2 is a hydraulic pressure inlet, 3 is a diaphragm, 4 is a pressure pad rubber, and 5 is a tray, which consists of a bottom main body 6, side walls 7a and 7b, and front and rear end walls. The inner wall surfaces of the side walls 7a, 7b and the front and rear end walls are sloped surfaces, thereby forming a funnel-shaped cavity 9 on the upper surface of the tray, and the pad rubber 4 is expanded and pressurized by the hydraulic pressure of the diaphragm 3. The press forming process is performed by filling the inside of the part 9 and pressing a metal plate (not shown) to be processed against a mold (not shown). 10a
10b is the aforementioned upper support block, and 10b is the lower support block, and the outer peripheral surfaces of these support blocks are formed so as to be able to come into surface contact with the inner wall surface of the high-pressure cylindrical container 1.

8 is the upper support block 10a for the diaphragm 3.
This is a fastening fitting for attaching to the bottom surface of the holder, and the details of the attachment are shown enlarged in Fig. 2.

In FIG. 2, the lip portion 1 of the diaphragm 3
The circumferential groove 12 provided on the lower surface of the upper support block 10a at the portion where the fastener 8 contacts the support block 10a is provided with a groove that is inserted between the fastening fittings 8 when the fastening fittings 8 are fastened to the support block 10a with the tightening bolts 13. A part of the lip portion 11 that has been removed is wedged in. This circumferential groove 12 extends over the entire circumference of the diaphragm 3, so that the lip portion 11 partially bulges out into the circumferential groove 12 over the entire circumference of the diaphragm 3.

Now, a mold (not shown) is placed in the cavity 9 of the tray 5.
A metal plate (not shown) is placed on top of the metal plate, the trays are placed inside the container 1, and after correctly positioning the support blocks 10a and 10b in their respective gaps, both ends of the container 1 are closed and pressurized. When the process begins, the diaphragm 3 expands due to the hydraulic pressure introduced from the hydraulic pressure inlet 2, and the pad rubber 4 presses the metal plate against the mold and presses it, filling the cavity 9. At this time, in the structure of the present invention, even if the diaphragm 3 is pulled outward around the diaphragm 3 due to the fluid deformation of the pad rubber 4, the fastening portion of the lip portion 11 remains intact because the lip portion 11 is embedded in the circumferential groove 12. It does not come off, and since the lip portion 11 is less deformed, the amount of contact with the lower surface of the support block 10a does not decrease.

According to the present invention, seal leakage during pressurization at the diaphragm lip can be reliably prevented simply by providing the same groove on the lower surface of the upper support block.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a rubber pad forming press according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view showing the main parts. 1: High pressure cylindrical container, 2: Hydraulic pressure inlet, 3: Diaphragm, 4: Pressure pad rubber, 5: Tray,
6: Tray bottom, 7a, 7b: Tray side wall, 8:
Fastening fitting, 9: Cavity, 10a, 10b: Upper support block, 11: Lip, 12: Circumferential groove, 13:
Tightening bolt.

Claims (1)

[Claims for Utility Model Registration] In a horizontally placed high-pressure cylindrical container, a mold is placed in the cavity of a tray having a flat cavity open on the top surface, and a workpiece is placed on the mold. The upper support block that holds the diaphragm on its lower surface within the high-pressure cylindrical container is located within the contact surface with the peripheral lip of the diaphragm. has a circumferential groove along the circumferential lip, and a portion of the flat surface of the diaphragm circumferential lip that faces the circumferential groove,
A diaphragm seal structure for a rubber pad forming press, characterized in that the diaphragm bulges into the circumferential groove by holding and fastening the diaphragm to an upper support block.