JPH06293087A - Production of reinforced yarn - Google Patents

Abstract

PURPOSE:To prevent the penetration of a fluid from an end surface by using yarn shrunk by the heat of a vulcanizing process as the yarn constituting a needle thread layer and shrinking the yarn in the vulcanizing process to fill the interstices between the yarns of the needle thread layer with the rubber of an intermediate rubber layer. CONSTITUTION:An inner tube 1 being the innermost layer 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. The surface of the bobbin thread layer 2 is covered with an intermediate rubber layer 3 and a braided needle thread layer 4 is formed on the intermediate rubber layer 3 and a skin rubber layer 5 is subsequently formed on the surface of the needle thread layer 4 by extrusion molding. Thereafter, the whole is arranged in a vulcanizer and held under heating to obtain a reinforced hose. In the obtained reinforced hose, the needle thread layer 4 is thermally shrunk at a time of vulcanization and the rubber of the intermediate rubber layer 3 protrudes to the interstices between the yarns of the needle thread layer 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 rubber layer forming step of forming an intermediate rubber layer on the lower thread layer surface, upper thread braiding step of braiding an upper thread layer on the intermediate rubber layer surface, and forming an outer rubber layer on the upper thread layer surface In the method of manufacturing a reinforcing hose, which comprises an outer rubber layer forming step and a vulcanizing step of vulcanizing and integrally joining the inner tube, the intermediate rubber layer and the outer rubber layer, Is characterized in that a yarn that shrinks due to heat in the vulcanization process is used, and the yarn of the intermediate rubber layer is filled in the gap between the yarns of the upper yarn layer by shrinking the yarn in the vulcanization process.

The vulcanization temperature is generally 120 to 180 ° C., and the material of the yarn that shrinks at that temperature is nylon, polyester, vinylon or the like. The shrinkage ratio of this yarn is preferably 1 to 5%. As the rubber of the intermediate rubber layer, it is preferable to use one having a Mooney viscosity of 30 to 50. This is because a rubber having a Mooney viscosity of 50 or more, which is generally used for the conventional intermediate rubber layer, has a small amount of deformation even when the yarn shrinks, and the filling property into the gap between the yarns becomes low. On the other hand, when the Mooney viscosity is less than 30, the strength of the intermediate rubber layer is reduced and the function of preventing friction of the intermediate rubber layer is reduced. Examples of the material of the rubber of the intermediate rubber layer include EPDM,
NR, IIR, etc.

[0009]

In the method of manufacturing the reinforcing hose of the present invention, the inner tube, the lower thread layer, the intermediate rubber layer, the upper thread layer and the outer rubber layer are formed in the same manner as in the conventional method, and the vulcanization step is performed. Here, the yarn forming the upper yarn layer shrinks due to the heat in the vulcanization process, so the upper yarn layer is reduced in diameter in the vulcanization process and the intermediate rubber layer is compressed. Then, the rubber of the unvulcanized intermediate rubber layer protrudes into the gap between the threads of the upper yarn layer by the compression force and fills the gap.

When a yarn that shrinks during cooling after vulcanization is used, the rubber of the vulcanized intermediate rubber layer is unevenly thickened by the shrinkage of the upper yarn layer and fills the gap between the yarns. In the reinforced hose thus obtained, the fluid is prevented from entering the upper thread layer from the end surface of the hose.

[0011]

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. This reinforcement 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 rubber 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 rubber 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, first, the inner tube 1 was formed from EPDM by extrusion molding. 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. Next, a 0.2 mm thick IIR sheet was wound around the surface of the lower thread layer 2 in a single layer to form the intermediate rubber layer 3. The IIR constituting this intermediate rubber layer 3 has a Mooney viscosity of 35. Then, a 1200 denier vinylon yarn was braided on the surface of the intermediate rubber layer 3 under the condition of three combined yarns-24 strokes to form an upper yarn layer 4. Next, upper thread layer 4
An outer rubber layer 5 was formed on the surface by extrusion molding from EPDM.

After that, the whole is placed in a vulcanizer and heated to 150 ° C.
A vulcanization step of heating and holding for 30 minutes was performed to obtain a reinforcing hose. In the obtained reinforcing hose, the upper thread layer 4 contracted by about 2% due to the heat during vulcanization, and the rubber of the intermediate rubber layer 3 protruded into the clearance between the threads and filled the clearance.

[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 the reinforcing hose in which the fluid is prevented from entering from the end surface 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 rubber 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 tube forming step of forming an inner tube, a lower thread braiding step of braiding a lower thread layer on the inner tube tube surface, and an intermediate rubber forming an intermediate rubber layer on the lower thread layer surface. A layer forming step, an upper thread braiding step of braiding an upper thread layer on the intermediate rubber layer surface, an outer rubber layer forming step of forming an outer rubber layer on the upper thread layer surface, the inner tube and the intermediate rubber A vulcanization step of vulcanizing and integrally joining a layer and the outer rubber layer, wherein the yarn forming the upper yarn layer is a yarn that shrinks due to the heat of the vulcanization process. A method of manufacturing a reinforcing hose, characterized in that the rubber of the intermediate rubber layer is filled into the gap between the yarns of the upper yarn layer by shrinking the yarn in the vulcanization step.