JPS5854306B2 - Diaphragm manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cloth-filled diaphragm, and more particularly, it provides a method for manufacturing a diaphragm with excellent durability by improving the embedding condition of the base cloth in the outer peripheral attachment part.

In a diaphragm using a rubber-like elastic material, in order to supplement the strength of the rubber membrane, a base fabric made of woven fiber fabric is embedded or attached to the rubber part over the entire area of the diaphragm. It is used in

A conventionally used cloth-filled diaphragm has a structure in which a base fabric 1 is buried close to the surface through a thin membrane part 10 and a peripheral mounting part 20, as shown in FIG. A sealing protrusion 4 is provided on one or both surfaces of the mounting portion 20.

In devices that use this type of diaphragm, when the membrane is pushed in one direction by fluid pressure acting on the membrane, a tensile force is applied along the membrane surface, but the membrane moves back and forth. Due to repeated operation, cracks are likely to occur in the rubber part due to this tensile force, especially in the vicinity of the sealing protrusion, resulting in a significant decrease in sealing performance, making it impossible to maintain the function of the device. There is.

As shown in FIG. 1, the base fabric 1 is buried close to the surface of the rubber part, and especially at the base of the sealing protrusion, as shown in FIG. Since the thread 2 may be embedded along the direction of the sealing protrusion 4, in such a region, the strength to resist the shearing force caused by the tensile force along the diaphragm surface due to the above-mentioned operating pressure is required. This is because the rubber portion is weakened, and as a result, the above-mentioned cracks are generated in the rubber portion.

The structure that is responsible for the drawbacks of the prior art diaphragms described above is a result of the commonly used methods of manufacturing them.

That is, as illustrated in FIG. 3, the rubber material and the woven fabric for the base fabric are placed in a lower mold 30 provided with a groove-shaped recess 31 for molding the attachment part and a membrane recess 32 for molding the membrane part. The woven fabric for the base fabric This is because the weaving threads remain near the surface of the rubber part.

(The diaphragm is not shown in FIG. 3.

) In order to eliminate the drawbacks of the diaphragm in the prior art described above, the present invention focuses on the structure and manufacturing method of the diaphragm that cause the drawbacks, and the present invention focuses on the structure and manufacturing method of the diaphragm that causes the drawbacks. The present invention presents a manufacturing method that provides a diaphragm structure that is deeply embedded within the mounting portion and exhibits strong bonding strength between the rubber portion and the base fabric.

FIG. 4 shows an example of the structure of the diaphragm provided by the present invention, and FIG. 5 shows an enlarged view of a part of the diaphragm near the sealing protrusion. It is buried near the surface in the area near the part 10, but it is gradually buried deeper into the rubber part of the attachment part 20 from near the inner side of the sealing protrusion 4 outward, and at the outer end of the attachment part 20. It is located near the end surface 23 on the opposite side to the membrane portion 10.

In the device in which the diaphragm according to the invention is used, the tensile force generated by the fluid pressure acting on the membrane part 10 is transmitted to the attachment part 20 by the base fabric 1 in the membrane part 10, and the tensile force is transmitted diagonally in the attachment part 20. It is absorbed by the elasticity of the rubber member constituting the attachment portion 20 through the base fabric 1 buried so as to cross outward.

Therefore, no shearing force is generated against the base of the sealing protrusion 40, which was observed in the conventional example, and no cracks are generated in that portion.

The molds used in the manufacturing method for producing the above-mentioned diaphragm structure and the preparation status before molding are shown below, and FIG. 7 shows the situation during molding. A protruding part 33 and a mounting part having an end face 34 forming the surface 12 (in this description, the reference numerals for each part of the diaphragm are used as shown in FIG. 4) and an outer surface 35 forming the inner axial surface 21 of the mounting part 20. The upper mold 40 has a base surface 36 for molding the end surface 23 of the mold, and the upper mold 40 is provided with a groove 41 for protrusions for molding the bottom plate 43 for molding the membrane surface 11 and the outer axial cylinder 22 of the mounting part. The unvulcanized elastic material 5 and the woven fabric 3 for the base fabric, which have been previously formed into a shape that covers the protrusion 33 of the lower mold, are placed in the lower mold 30. The upper mold 40 is placed on top of the mold, and pressure is applied as shown in FIG.

As the forming by pressure progresses, the elastic material moves upward through the weaves of the woven fabric 3 and the woven fabric is buried in the elastic material, but the outer edge of the woven fabric is Mold recess outer surface 44
The mounting part 2 is pulled by the edge of the mounting part 2 and is deeply sunk into the mounting part 20.
0 is reached in a diagonal direction, and a diaphragm as shown in FIG. 4 is obtained.

In the diaphragm manufacturing method of the present invention, the protrusion forming the inner axial surface of the mounting portion of the diaphragm is formed on one mold, and the recess forming the outer axial surface of the mounting portion is formed on the other mold. The woven fabric for the base fabric is formed in the mold so that during molding, the vicinity of the woven fabric for the base fabric is pulled against the edge of the inner surface of the recess. Since the diaphragm manufactured according to the present invention is buried, the bonding force between the base fabric and the rubber portion at the attachment portion is maintained firmly, and as a result, cracks and breakage near the attachment portion, which were observed in diaphragms according to the prior art, are avoided. is prevented and normal diaphragm function is maintained for an extended period of time.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing the structure of a conventionally used Merchant diaphragm, Fig. 2 is a partially enlarged view of the diaphragm shown in Fig. 1, and Fig. 3 is a diaphragm used in manufacturing the diaphragm shown in Fig. 1. A vertical sectional view showing the structure of a molding die, No. 4
The figure is a longitudinal sectional view showing the structure of a diaphragm according to the present invention.
Figure 5 is a partially enlarged view of the diaphragm shown in Figure 4;
The figure is a longitudinal sectional view showing the structure of the molding die used to manufacture the diaphragm shown in Fig. 4 and the situation immediately before molding, and Fig. 7 is a longitudinal sectional view showing the situation during molding with the mold shown in Fig. 6. It is a front view. 1...Base fabric, 2...Weaving yarn, 3...
...Woven fabric, 4...Sealing protrusion, 5...
Elastic material, 10...Membrane part, 11...Membrane part surface, 12...Membrane part back side, 20...
・Mounting part, 21... Inner axial surface, 22...
... Outer axial surface, 23 ... End surface of the mounting part,
30...Lower mold, 31...Groove recess,
32... Recess for membrane body, 33... Protrusion, 34... End face of protrusion, 35... Outer surface of protrusion, 36... ... Base surface, 40 ... Upper mold, 41 ... Groove for protrusion, 42 ... Recess, 43 ... Bottom surface of recess, 44 ... ...inner surface of the recess.

Claims (1)

[Claims] 1. A protrusion 33 that forms the back surface 12 of the membrane portion, the inner axial surface 21 of the mounting portion 20, and the mounting end surface 23 of the mounting portion 20.
One mold 30 is provided with a membrane portion surface 11. A rubber-like elastic material 5 and a woven base fabric 3 are placed between the other mold 40, which is provided with a sealing protrusion 4 and a recess 42 for molding the outer axial surface 22 of the attachment part 20, and the Both molds 30
．． 40, so that a portion near the edge of the woven fabric 3 forms the recess 4.
2, the woven fabric 3 spreads from the inside to the outside of the attachment part 20, and shifts in the axial direction to move inside the attachment part 20 in an oblique direction. A method for manufacturing a diaphragm, characterized by forming the diaphragm so that it is buried across the diaphragm.