JPH07259992A - Rolling diaphragm and manufacture thereof - Google Patents

Abstract

PURPOSE:To inhibit a reinforcing fabric from being deviated by an inner rubber layer, particularly in a upper surface corner part. CONSTITUTION:In a rolling diaphragm in which a hut-like sectional shape reinforcing fabric 1 has, at least one surface thereof, a rubber layer, a leakage preventing fabric 7 having a texture density which is greater than that of the reinforcing fabric 1 is laid in each of corner parts of the hut-like shape upper surface of the fabric 1 on the rubber layer side. Since the leakage preventing part is provided in each corner part of the hut-like shape upper surface of the rolling diaphragm, the rubber can hardly flow from the texture of the reinforcing fabric (the leakage preventing fabric having a high texture density restrains outward leakage of the rubber) when the reinforcing fabric is drawn in the flowing direction of the rubber during vulcanization, thereby it is possible to prevent the reinforcing fabric from being deviated from the inner rubber layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling diaphragm and a method of manufacturing the rolling diaphragm, and more particularly, to a rolling diaphragm having a reinforcing cloth interposed between the rolling diaphragm and a manufacturing method thereof to prevent fluid leakage.

[0002]

2. Description of the Related Art As an example of a rolling diaphragm containing cloth, as shown in the sectional view of FIG. 4, an inner rubber layer 2 is provided on one side (rubber side) of a reinforcing cloth 1 having a hat-shaped cross section, and a reinforcing cloth for vulcanization. The shape is such that a bleeding rubber layer 3 leached from the inside to the outside through a reinforcing cloth is provided.

In the manufacture of such a diaphragm, for example, in the case of a rolling diaphragm on the cloth piece side, a non-addition is made between the lower mold 4 having the cap-shaped protrusion 41 and the upper mold 5 having the corresponding recess 51. A rubber vulcanizate is attached and molded into a hat-shaped cross section, and this is semi-vulcanized (Fig. 5). After molding the semi-vulcanized rubber 6 in this way, the upper mold 5 is opened, the reinforcing cloth 1 molded in a hat shape is covered, and the upper mold 5 is further covered for vulcanization (FIG. 6). By carrying out the vulcanization in this manner, the semi-vulcanized rubber 6 exudes thinner than the weave of the reinforcing cloth 1 to form the exuded rubber layer 3.

[0004]

In the manufacturing method as described above, the gap between the upper mold 5 and the lower mold 4 has the film thickness of the finished product. For this reason, when the reinforcing cloth 1 is covered on the semi-vulcanized rubber 6 and the main vulcanization is performed, the rubber is excessive by the thickness of the cloth. Since the rubber is incompressible, this extra rubber will flow out of the mold. When this extra rubber flows out during the main vulcanization, the reinforcing cloth 1 is pulled in the rubber flow direction, and the upper surface portion of the diaphragm, especially the upper surface corner R portion (A portion in FIG. 4) easily enters the rubber, Since the reinforcing cloth 1 is closer to the inner rubber layer 2 (see FIG. 7B), it is extremely difficult to obtain the ideal arrangement of the reinforcing cloth 1 as shown in FIG. 7A. It was When the reinforcing cloth 1 is exposed from the inner rubber layer as shown in FIG. 7B, the fluid enters the fibers of the reinforcing cloth 1, travels along the fibers, and leaks from the flange portion.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the reinforcing cloth 1 has a top surface corner R in particular.
An object of the present invention is to provide a rolling diaphragm which is not unevenly distributed in the inner rubber layer 2 in some parts, and a manufacturing method thereof.

In order to solve the above-mentioned problems, a rolling diaphragm according to the present invention is a rolling diaphragm having a rubber layer on at least one surface of a reinforcing cloth 1 having a hat-shaped cross section, and the reinforcing cloth 1 is provided at a corner portion of the hat-shaped upper surface. A leak-preventing cloth 7 having a tighter texture is provided on the rubber side of the reinforcing cloth 1.

In the method for manufacturing a rolling diaphragm according to the present invention, a step of molding a semi-vulcanized rubber having a hat-shaped cross section, and a weave rather than a reinforcing cloth is covered so as to cover the corners of the hat-shaped upper surface of the semi-vulcanized rubber. The method is characterized by including a step of providing a leak-proof cloth, a step of covering the semi-vulcanized rubber with a reinforcing cloth formed in advance in a hat shape, and a step of vulcanizing the semi-vulcanized rubber.

According to the present invention, since the leakage preventing cloth is provided at the corner portion of the upper end surface of the rolling diaphragm, which has a hat shape, when the reinforcing cloth is pulled in the flow direction during the main vulcanization, the reinforcing cloth is provided. The rubber is less likely to flow outward than the weave (the leak-proof cloth having the weave suppresses the outward leakage of the rubber), so that the reinforcing cloth 1 is not unevenly distributed in the inner rubber layer 2. Brings advantages.

[0009]

FIG. 1 is an enlarged cross-sectional view of a cap-shaped upper corner of a rolling diaphragm of the present invention. As is apparent from this figure, an inner rubber layer 2 is provided on the rubber side of a hat-shaped reinforcing cloth 1.
It has a structure in which an exuded rubber layer 3 is formed by exuding the inner rubber layer 2 through the reinforcing cloth 1 during vulcanization.

In manufacturing such a rolling diaphragm, as shown in FIG. 2, a leak preventive cloth 7 is provided so as to cover the hat-shaped upper corner 61 of the hat-shaped molded semi-vulcanized rubber 6. Cover.

After the hat-shaped semi-vulcanized rubber 6 is covered with the leakage prevention cloth 7 in this manner, the cap-shaped reinforcing cloth 1 is covered (see FIG. 3), and the upper mold (not shown) is covered. Perform main vulcanization.

By thus providing the leak-preventing cloth 7 at the upper corner 61 of the hat-shaped upper surface, the rubber flowing at the time of the main vulcanization is directed toward the outer side of the hat-shaped reinforcing cloth 1 by the leak-preventing cloth 7 which is clogged. Will be suppressed. Therefore, the reinforcing cloth 1 is not unevenly distributed toward the inner rubber layer 2,
Leakage of pressurized fluid can be prevented.

As described above, the leak preventive cloth 7 prevents a large amount of rubber from leaking from the reinforcing cloth during the main vulcanization, but when almost no leak occurs,
In the exuded rubber layer 3 in the corner portion 61, since there is no exudation of rubber, the cloth surface is extremely conspicuous. On the contrary, if the leakage is too large, it is not possible to prevent uneven distribution of the reinforcing cloth 1.

The type of the leak preventive cloth 7 depends on the size and shape of the rolling diaphragm. Generally speaking, a rolling diaphragm with a smaller shape has a smaller fiber diameter and uses a cloth having a higher weave density. Further, the leak preventive cloth 7 having a thickness of 1/4 to 1/3 of the reinforcing cloth 1 is used. If it is thinner than 1/4 of the reinforcing cloth, the performance (cloth strength and workability) as exudation prevention cloth is poor and it cannot be used practically. On the other hand, if it is thicker than 1/3, the eyes become coarse and the rubber exudes. This is not preferable because the rolling diaphragm itself has a large thickness due to the poor prevention property and the thickness of the prevention cloth.

[0015]

As described above, according to the present invention,
Since a leak-proof cloth, which is tighter than the reinforcing cloth, is provided below the corner of the hat-shaped upper surface of the hat-shaped reinforcing cloth, the outward flow of the rubber is suppressed during the main vulcanization, and therefore the reinforcing cloth is covered with the inner rubber layer. It will not be unevenly distributed in the direction. Therefore, there is an advantage that the pressurized fluid does not leak along the fibers of the reinforcing cloth.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a hat-shaped upper surface corner portion of a rolling diaphragm of the present invention.

FIG. 2 is an exploded perspective view when manufacturing the rolling diaphragm of the present invention.

FIG. 3 is a sectional view showing a set state when manufacturing the rolling diaphragm of the present invention.

FIG. 4 is a sectional view of a conventional rolling diaphragm.

FIG. 5 is a cross-sectional view when manufacturing a hat-shaped semi-vulcanized rubber.

FIG. 6 is a sectional view showing a set state when a conventional rolling diaphragm is manufactured.

FIG. 7a is an enlarged cross-sectional view of a hat-shaped upper surface corner portion of an ideal rolling diaphragm.

FIG. 7b is an enlarged cross-sectional view of a hat-shaped upper surface corner portion of a realistic rolling diaphragm.

[Explanation of symbols]

 1 Reinforcement cloth 2 Inner rubber layer 3 Exuded rubber layer 6 Semi-vulcanized rubber 7 Leak prevention cloth

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Claims (3)

[Claims] 1. In a rolling diaphragm having a rubber layer on at least one surface of a reinforcing cloth having a hat-shaped cross section, a leak-preventing cloth having a texture closer to that of the reinforcing cloth than the reinforcing cloth is provided on a rubber side of the reinforcing cloth. Rolling diaphragm characterized by being installed in. 2. The leak preventive cloth is 1/4 to 1 of the thickness of the reinforcing cloth.
The rolling diaphragm according to claim 1, wherein the rolling diaphragm has a thickness of / 3. 3. A step of molding a semi-vulcanized rubber having a hat-shaped cross-section, and a step of providing a leak-proof cloth which is more textured than a reinforcing cloth so as to cover a corner of the hat-shaped upper surface of the semi-vulcanized rubber,
A method of manufacturing a rolling diaphragm, comprising: a step of covering the semi-vulcanized rubber with a reinforcing cloth having a hat shape in advance; and a step of vulcanizing the semi-vulcanized rubber.