JPH054202B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a vulcanized rubber product such as a rubber sheet.

[Background Art and Issues to be Solved] Vulcanized rubber products are widely used in rubber hoses, flexible joints, air springs, and the like. As a method for producing such vulcanized rubber products, a method of placing a rubber composite in a metal mold and vulcanizing it is widely used.

However, molds are expensive, and assembly and disassembly after vulcanization are complicated. Furthermore, there is a problem in that bubbles are likely to be generated between the rubber composites during vulcanization.

For cylindrical rubber products with a relatively large diameter, a manufacturing method is also used in which a cloth sheet is wrapped around the outside and the outside mold is omitted.

As an example, as shown in FIG. 4, in the conventional structure, a composite body consisting of an inner rubber layer 12, a reinforcing layer 14, and an outer rubber layer 16 is wrapped around the outer periphery of a mandrel 10, and a cloth sheet 18 is wrapped around the outside of the outer rubber layer 16. is spirally wound to tighten the outer rubber layer 16.

However, the work of wrapping a cloth sheet around the outside of a large-diameter rubber composite is a complicated and time-consuming work, and the same number of man-hours is required when dismantling it after vulcanization. Further, in this method, although the air between the layers of the molded body is squeezed out by the external pressure when the sheet is wrapped, the air bubbles are not completely discharged.

In consideration of the above-mentioned facts, the present invention aims to provide a method for manufacturing a vulcanized rubber product that does not require a mold placed outside the rubber composite and can effectively remove air bubbles between layers.

[Summary and operation of the invention] In the method for manufacturing a vulcanized rubber product according to the present invention, a rubber composite is placed on a core, and a layer between the outer layer of the rubber composite and the core or covering the rubber composite is provided. Since the space between the covering body and the core body is sealed and vulcanization is performed while applying vacuum suction inside the sealed part, the comb composite generates pressure to be pressed against the core body, eliminating the need for an outer mold. air bubbles are efficiently discharged.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention, in which a cylindrical rubber composite 22 is wound around the outer periphery of a mandrel 20 that is a cylindrical core. There is. This rubber composite 22 has a three-layer structure including an inner rubber layer 24, a reinforcing layer 26, and an outer rubber layer 28.

The outer layer rubber 28 has inner layer rubber 24 at both ends in the axial direction,
The extension portion 30 protrudes beyond the reinforcing layer 26 and is in contact with the outer periphery of the mandrel 20 . A tightening band 32 is tightened around the outer periphery of these extensions 30 to press the extensions 30 against the outer periphery of the mandrel 20. Therefore, the outer layer rubber 28 and the mandrel 2
0, and this sealed portion is connected to a vacuum pump 36 via a suction port 34 formed in the mandrel 20.

In this embodiment, if the air between the outer layer rubber 28 and the mandrel 20 is suctioned from the suction port 34 by operation of the vacuum pump 36, the rubber composite 22
generates a force pressing against the mandrel 20, and air between each layer of the rubber composite 22 is efficiently discharged. Therefore, there is no need for a mold to hold the outside of the outer rubber layer 28, a rubber composite 22 with internal air bubbles removed by vulcanization is completed, and the molding time can be halved compared to conventional rubber composites.

Note that the outside of the outer rubber layer 28 may be auxiliary pressed by steam pressure or the like.

[Second Embodiment] FIG. 2 shows a second embodiment of the present invention. In this embodiment, unlike the first embodiment, the outer rubber layer 28 of the rubber composite 22 has the same axial dimensions as the inner rubber layer 24 and the auxiliary layer 26. Further, in this embodiment, the outer side of the rubber composite 22 is covered with a rubber bag 38 which is a covering member. The rubber bag 38 has a cylindrical shape and has a longer axial length than the rubber composite 22 and further protrudes from both ends of the rubber composite 22 in the axial direction. A tightening band 32 similar to that of the previous embodiment is applied to this protrusion and tightened to the outer periphery of the mandrel 20.

In this embodiment as well, a suction port 34 is formed in the mandrel 20 and is communicated with a vacuum pump 36. Therefore, by vulcanizing while maintaining the vacuum suction state by the vacuum pump 36, a cylindrical rubber composite 22 is completed, and the product becomes a product with no internal air bubbles.

[Third Embodiment] FIG. 3 shows a third embodiment of the present invention. This example is an example for obtaining a vulcanized rubber product in which a hemispherical part 42 is connected to the axial end of a cylindrical part 40.

The mandrel 44 has a cylindrical portion 44A and a hemispherical portion 44B that match the inner shape of the product.

In this embodiment, the ends of the inner rubber layer 24 and the outer rubber layer 28 are folded back near the axial center of the mandrel hemispherical part 44B and are connected to each other, and the reinforcing layer 26 is also connected to the axial center of the hemispherical part 44B. It has a configuration in which it is wound around a ring-shaped reel 47 near the end and reversed. The other end of the outer rubber layer 28 is connected to the cylindrical portion 44A by the tightening band 32.
is being pushed to.

In this embodiment, the mandrel 44 of the outer layer rubber 28
The suction port 34 is located near the tightening part of the hemispherical part 44B.
A plurality of suction ports 49 are provided penetratingly near the joint between the inner rubber layer 24 and the outer rubber layer 28, and the inside of the mandrel 44 is connected to a vacuum pump (not shown). The suction port 34 is a ring groove 3 carved in a ring shape on the outer periphery of the mandrel 44A.
It communicates with 4A.

Furthermore, in this mandrel 44, a hemispherical portion 44B
A plurality of suction grooves 51 are formed in the axial direction of the mandrel 44, extending radially toward the outer periphery of the mandrel 44 and reaching near the ring groove 34A in the axial direction of the cylindrical portion 44A. are connected to either.

Note that a stopper 53 is brought into contact with the end of the cylindrical portion 44A to press the connecting portion between the inner rubber layer 24 and the outer rubber layer 28 in the axial direction.

Therefore, in this embodiment as well, the suction ports 34, 49
If vulcanization is performed while vacuum suction is applied, a vulcanized rubber product with fewer air bubbles and without the need for an outer mold can be created.

In the above embodiment, a mandrel is used to support the inner rubber, but it is also possible to use a flexible core by pressurizing the inside of the rubber composite. Furthermore, in each of the above embodiments, the present invention was explained in the case where a cylindrical vulcanized rubber product is produced, but the present invention can also be applied to vulcanized rubber products having other shapes such as a flat rubber sheet. It is.

[Effects of the Invention] As explained above, in the method for producing a vulcanized rubber product according to the present invention, the space between the outer layer of the rubber composite and the core, or between the covering body covering the rubber composite and the core is sealed. Since vulcanization is performed while suctioning and suctioning, it is possible to obtain a vulcanized rubber product without the need for an outer mold and with fewer bubbles.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the method for manufacturing a vulcanized rubber product according to the present invention, FIGS. 2 and 3 are cross-sectional views showing second and third embodiments of the present invention, respectively, and FIG. FIG. 2 is a cross-sectional view showing a conventional manufacturing method. 20, 44...Mandrel, 22...Rubber composite, 28...Outer layer rubber, 36...Vacuum pump, 3
8...Rubber bag.

Claims (1)

[Claims] 1 Place the rubber composite on the core, seal between the outer layer of the rubber composite and the core, or between the coating covering the rubber composite and the core, while applying vacuum suction inside the sealed part. A method for producing a vulcanized rubber product characterized by vulcanization.