JPH06189428A - Manufacture of multilayer rubber molding - Google Patents

Abstract

PURPOSE:To remarkably reduce the deformation of an inner layer rubber molding by using rubber material having the hardness larger than that of an outer layer rubber molding for the inner layer rubber molding. CONSTITUTION:An inner conductive rubber layer molding 1 and an outer conductive rubber layer molding 3 are inserted into a core bar 7 and are fastened in there. After that, the core bar is stored in a molding die 8 and then insulating rubber is injected between the inner conductive rubber layer molding 1 and the outer conductive rubber layer molding 3 from an insulating rubber injection gate hole 4 to form an insulating layer 2. Then, the insulating layer 2 is cured to be incorporated into one body with the moldings. At that time, the inner conductive rubber layer molding 1 is applied with stress in the direction 5 of the insulating rubber flow due to injection pressure of the insulating rubber. However, the inner conductive rubber layer molding 1 is formed with rubber having the hardness larger than that of the outer conductive rubber layer molding 3, so the inner conductive rubber layer molding 1 deforms only a little when such a stress is applied causing no problem. Because of this reason, the inner conductive rubber layer molding 1 can be made thin and the size of the product can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal conductive layer, such as a plug-in type insulation tube used for connecting a power cable.
The present invention relates to a method for producing a multi-layer rubber molded product in which an insulating layer and an outer conductive layer are sequentially laminated and integrally formed in a multi-layered structure.

[0002]

2. Description of the Related Art FIG. 1 is a vertical cross section of an example of a plug-in type straight type insulating tube used for a connecting portion of a power cable. In the drawing, 1 is an internal conductive rubber layer, 2 is an insulating rubber layer, 3 is an external conductive rubber layer provided with a gate portion 4, and these rubber layers are formed of, for example, ethylene-propylene rubber or butyl rubber. To form such a plug-in type insulating cylinder, first, the inner conductive rubber layer molded product 1 and the outer conductive rubber layer molded product 3 are molded in a separate step, and the core metal 7 is molded into the inner conductive rubber layer molded product 1. And the external conductive rubber molded product 3 are inserted and mounted, and the external conductive rubber molded product 3 is housed and mounted in a mold having a desired shape. From the insulating rubber injection hole 4 (commonly called a gate portion) of the external conductive rubber layer molded product 3 It is manufactured by injecting and filling insulative rubber, and molding and integrating the insulating layer 2 between the inner conductive rubber molded product 1 and the outer conductive rubber molded product 3.

[0003]

According to this method, when the external conductive rubber layer molded article 3 is molded in a separate step in advance, the external conductive rubber layer molded article 3 usually has a center shape as shown in FIG. Since the portion is thick, the rubber material for molding is usually a rubber having a low hardness of JISA-60 or less in order to reduce the extraction force when the molded product 3 is extracted from the cored bar 7 after being molded into a predetermined shape. Used material. Similarly, this low hardness rubber material was also used as the molding rubber material of the internal conductive rubber layer molded article 1. The preformed inner conductive rubber layer molded product 1 and the outer conductive rubber layer molded product are inserted and mounted in a core metal 7 as shown in FIG. 3, which is housed and mounted in a mold 8.
When the insulating layer 2 is molded by injecting the insulating rubber between the inner conductive rubber layer molded product 1 and the outer conductive rubber layer molded product via the gate portion 4, the inner conductive rubber layer molded product 1 is lengthened by the injection pressure of the insulating rubber. There was a problem that it was deformed in the vertical direction 6.
As a countermeasure against this, if the thickness of the inner conductive rubber layer molded article 1 is increased (4 mm or more) so that the inner conductive rubber layer molded article 1 is not deformed by the pressure at the time of injecting the insulating rubber, a new problem occurs that the outer dimension of the product becomes large. did.

[0004]

The present invention provides a method for producing a multi-layer rubber molded product in which an inner layer, an intermediate layer, and an outer layer are sequentially laminated and integrated to solve the above-mentioned problems. Insert the molded inner layer rubber molded product and outer layer rubber molded product into the cored bar, store and mount it in the mold, and inject and fill the rubber material for the intermediate layer from the gate of the mold, and add it. In the method for producing a multilayer rubber molded product in which an inner layer, an intermediate layer, and an outer layer are integrated by being vulcanized, an inner layer rubber molded product molded with a rubber material having a hardness higher than that of the outer layer rubber molded product is used. It is characterized by performing. The present invention will be described below with reference to embodiments shown in the drawings. 1 to 3 are explanatory views of a procedure for forming a linear plug-in type insulating cylinder by the manufacturing method of the present invention. First, J
The inner conductive rubber layer molded product 1 is made of a conductive rubber of IS-A 70 or more. Similarly, as shown in FIG. 2, JIS-A6
The outer conductive rubber layer molded product 3 is formed on the cored bar 7 using a conductive rubber of 0 or less. At this time, the outer conductive rubber layer molded product 3 is provided with one to several gate holes communicating with the insulating rubber injection holes (not shown) of the mold. In this way, the preformed inner conductive rubber layer molded product 1 and the outer conductive rubber layer molded product 3 are attached to the core metal 7
3 is inserted and mounted in the mold 8 as shown in FIG. 3, and the internal conductive rubber is inserted through the rubber injection hole of the mold and the insulating rubber injection gate hole 4 of the external conductive rubber layer molded product 3. Insulating rubber is injected between the layer molded product 1 and the outer conductive rubber layer molded product 3, the insulating layer 2 is molded, and this is vulcanized to be integrated to form a linear insertion insulating cylinder having a structure as shown in FIG. obtain. At this time, the insulating rubber injected from the gate part of the mold is
As shown in FIG. 2, the outer conductive rubber layer molded product 1 and the inner conductive rubber layer molded product 3 are filled through the inner conductive rubber layer molded product 1. In the present invention, the inner conductive rubber layer molded article 1 is molded with a rubber material having a hardness higher than that of the outer conductive rubber layer molded article 3 in the present invention. The amount of deformation is slight and does not pose a problem.

[0005]

According to the method of the present invention, when the rubber material for the intermediate layer is injected and filled to mold the intermediate rubber layer, even if the rubber article for the inner layer receives stress due to the injection pressure of the rubber material for the intermediate layer, the rubber article for the inner layer is obtained. Is made of a rubber material having a hardness higher than that of the outer layer rubber molded product, the deformation amount of the inner layer rubber molded product is greatly reduced.

[0006]

In the method for producing a multi-layer rubber molded product of the present invention, since the inner rubber layer molded product is formed of a rubber material having a higher hardness than other rubber layer materials, the inner rubber layer molded product is an intermediate product. Even when receiving the injection pressure of the rubber material, the amount of deformation is extremely small. Therefore, the inner layer molded product can be made thinner, and the product can be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a linear plug-in type insulating cylinder.

FIG. 1 is a cross-sectional view illustrating a pattern for manufacturing an external conductive rubber layer molded product using a cored bar.

FIG. 3 shows a flow of insulating rubber when an insulating rubber is injected between an inner conductive rubber layer molded product and an outer conductive rubber layer molded product using a mold, and a pattern in which the inner conductive rubber layer molded product is deformed. It is an explanatory view explaining.

[Explanation of symbols]

 1 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ matter of the outside conductive rubber layer. Deformation direction of inner conductive rubber layer molded product 7 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥

Claims (1)

[Claims] 1. An inner layer rubber molded product and an outer layer rubber molded product, which have been separately molded in advance, are inserted into and mounted on a cored bar, and the cored bar is housed and mounted in a mold, and the gate part of the mold is used for an intermediate layer. In a method for producing a multi-layered rubber molded product in which an inner layer, an intermediate layer, and an outer layer are integrated by filling and vulcanizing a rubber material, a rubber material having a hardness higher than that of the outer layer rubber molded product A method for producing a multi-layered rubber molded product, characterized in that it is carried out by using a molded product.