JPH06293088A - Production of reinforced hose - Google Patents

Abstract

PURPOSE:To prevent the penetration of a fluid from an end surface by using a resin softened by the heat of a vulcanizing process in an intermediate resin layer and softening the intermediate resin layer in the vulcanizing process to fill the interstices between the yarns of a needle thread layer with the resin. CONSTITUTION:An inner tube 1 is formed by extrusion molding and a braided bobbin thread layer 2 pretreated with a latex type adhesive is formed on the surface of the inner tube 1. A sheet composed of a resin softened at vulcanizing temp. is singly wound around the bobbin thread layer 2 to form an intermediate resin layer 3 and a braided needle thread layer 4 is formed on the surface of the intermediate resin layer 3 and, subsequently, a skin rubber layer 5 is formed on the surface of the needle thread layer 4 by extrusion molding. Thereafter, the whole is arranged in a vulcanizer to be vulcanized to obtain a reinforced hose. In the obtained reinforced hose, the intermediate resin layer 3 is softened at vulcanizing temp. and the needle thread layer 4 is also shrunk and the resin of the intermediate resin layer 3 protrudes to the interstices between the yarns of the needle thread layer 4 to fill the interstices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a reinforcing hose which is used in a pressure fluid passage such as a hydraulic hose and has a reinforcing thread layer braided in the middle.

[0002]

2. Description of the Related Art A hose used for a flow path of a pressure fluid such as a hydraulic hose is required to have a strength capable of withstanding a high pressure.
Therefore, the hose base made of rubber or resin is often insufficient in strength, and a hose having a reinforcing thread layer in which reinforcing threads are braided in the middle is generally used.
Also, a single layer of reinforcing yarn may be insufficient, and in such a case, a reinforcing hose having a plurality of reinforcing yarn layers is used.

By the way, in a reinforcing hose having a reinforcing thread layer,
The reinforcing yarn layer is inevitably exposed on the end face. Therefore, in the structure in which the reinforcement hose and the mouthpiece are fastened together, if the fluid flowing in the reinforcement hose enters between the mouthpiece and the hose and reaches the end surface of the hose, the fluid may permeate into the reinforcement thread layer due to the capillary phenomenon. is there. Therefore, conventionally, a latex adhesive (commonly referred to as RFL) is applied to the reinforcing yarn layer to fill the gap between the yarns.

In the conventional manufacturing method for manufacturing such a reinforcing hose, first, an inner tube is formed by extrusion molding,
On the surface thereof, a reinforcing yarn layer is braided using a yarn made of synthetic fiber such as rayon, polyester or vinylon. Then, a latex-based adhesive is applied to the reinforcing yarn layer by a dipping method or the like, and after moisture is dried, an outer rubber layer is formed on the surface of the reinforcing yarn layer by extrusion molding. And it is integrated by vulcanizing the whole. When a plurality of reinforcing yarn layers are formed, a plurality of reinforcing yarn layers are formed with an intermediate rubber layer interposed for the main purpose of preventing friction between the reinforcing yarn layers.

[0005]

However, the latex-based adhesive (RF) used in the above conventional manufacturing method is used.
Although L) had good adhesiveness to the inner tube and the outer rubber layer, it could not be said that its permeability to the reinforcing yarn layer was sufficient. Further, since this adhesive contains a large amount of water, there is a problem that productivity is poor because the drying process requires a long time.

Therefore, in recent years, braiding of threads pretreated with the above-mentioned latex adhesive has been carried out.
Only by braiding the pre-treated yarn, a gap is inevitably generated during braiding, which is disadvantageous in preventing fluid from entering. The present invention has been made in view of the above circumstances, and it is possible to fill a gap between threads without lowering productivity even when using a thread pretreated with a latex adhesive. With the goal.

[0007]

A method of manufacturing a reinforcing hose according to the present invention, which solves the above problems, comprises an inner tube forming step of forming an inner tube and a lower thread for braiding a lower thread layer on the surface of the inner tube. Braiding step, intermediate resin layer forming step of forming an intermediate resin layer on the lower thread layer surface, upper thread braiding step of braiding an upper thread layer on the intermediate resin layer surface, and forming an outer rubber layer on the upper thread layer surface In a method for manufacturing a reinforcing hose comprising an outer rubber layer forming step and a vulcanizing step of vulcanizing an inner tube and an outer rubber layer, a resin which is softened by heat of the vulcanizing step is used for the intermediate resin layer, It is characterized in that the intermediate resin layer is softened in the vulcanization step and is filled in the gap between the threads of the upper thread layer.

The vulcanization temperature is generally 120 to 180 ° C., and polyethylene is a resin that softens at that temperature. It is desirable to use nylon, vinylon, polyester, or the like, which shrinks due to heat during vulcanization, as the thread forming the upper thread layer. When the upper yarn layer is braided using such a yarn, it shrinks due to heat during vulcanization and penetrates into the intermediate resin layer, so that the gap is more easily filled.

[0009]

In the method of manufacturing a reinforced hose of the present invention, each layer is formed and the vulcanization step is performed in the same manner as in the conventional method except that the intermediate resin layer is replaced with the intermediate resin layer. Here, since the resin forming the intermediate resin layer is softened by the heat of the vulcanization step, it enters the gap between the yarns of the upper yarn layer and fills the gap.
This prevents the fluid from entering the upper thread layer from the end surface of the hose.

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. Figure 1
The reinforcing hose manufactured by the manufacturing method of the embodiment of the present invention is shown together with the mouthpiece. The reinforcing hose is a high-pressure hose for automobiles, and includes an innermost tube 1 as an innermost layer, a lower thread layer 2 braided on the surface of the inner tube 1, an intermediate resin layer 3 coated on the lower thread layer 2 surface, It is composed of an upper thread layer 4 braided on the surface of the intermediate resin layer 3 and an outer rubber layer 5 covered on the surface of the upper thread layer 4, and a cap 6 is fastened to the end portion by caulking.

In the manufacturing method of this embodiment for manufacturing this reinforcing hose, the inner tube 1 was first formed by extrusion molding from EPDM. Next, a 1500 denier polyester yarn previously treated with a latex adhesive (RFL) was braided on the surface of the inner tube 1 under the condition of double-plied yarn-20 shots to form a lower yarn layer 2. Then, a polyethylene sheet having a thickness of 0.2 mm is wound around the surface of the lower thread layer 2 in a single layer to form the intermediate resin layer 3
Was formed. The polyethylene forming the intermediate resin layer 3 has a thermal softening temperature of 90 ° C and a melting point of 110 ° C.

On the surface of the intermediate resin layer 3, 1200
A denier vinylon yarn was braided under the condition of three-plying yarn-24 strokes to form the upper yarn layer 4. Then EPD on the surface of the upper thread layer 4
The outer rubber layer 5 was formed from M by extrusion molding. Then, the whole was placed in a vulcanization can, and a vulcanization step of heating and holding at 150 ° C. for 30 minutes was performed to obtain a reinforcing hose.

In the obtained reinforcing hose, the intermediate resin layer 3 is softened by heat during vulcanization, and the upper yarn layer 4 is shrunk, so that the resin of the intermediate resin layer 3 is formed in the gap between the yarns of the upper yarn layer 4. It overflowed and filled the gap.

[0014]

That is, according to the method of manufacturing a reinforcing hose of the present invention, the gap between the yarns of the reinforcing yarn layer is surely filled, so that a reinforcing hose in which fluid is prevented from entering from the end face is equivalent to the conventional one. It can be manufactured in the number of steps.

[Brief description of drawings]

FIG. 1 is a front view of a reinforcing hose manufactured by a manufacturing method according to an embodiment of the present invention with a mouthpiece partially shown in section.

[Explanation of symbols]

1: Inner tube tube 2: Lower thread layer
3: Intermediate resin layer 4: Upper thread layer 5: Outer rubber layer
6: Base

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location B29K 105: 24 B29L 23:00 4F

Claims (1)

[Claims] 1. An inner tube forming step for forming an inner tube, a lower thread braiding step for braiding a lower thread layer on the inner tube tube surface, and an intermediate resin for forming an intermediate resin layer on the lower thread layer surface. A layer forming step, an upper thread braiding step of braiding an upper thread layer on the surface of the intermediate resin layer, an outer rubber layer forming step of forming an outer rubber layer on the upper thread layer surface, the inner tube and the outer rubber A vulcanization step of vulcanizing a layer, and a method of manufacturing a reinforcing hose comprising: a resin that is softened by the heat of the vulcanization step is used for the intermediate resin layer, and the intermediate resin layer is formed in the vulcanization step. A method of manufacturing a reinforcing hose, comprising softening and filling the gap between the threads of the upper thread layer.