JPS62184843A - Manufacture of high-pressure rubber hose - Google Patents

Abstract

PURPOSE:To improve the productivity of a rubber hose, by curing a blown-off rubber part under cooling, and by removing the cooled blown-off rubber part, under applying an external force and by covering it with a rubber layer of an outer tube and vulcanizing it. CONSTITUTION:A rubber layer 13 of an inner tube is molded under extrusion into a metal mandrel 11, and a reinforcing layer 15 is formed n the rubber layer 13 of the inner tube with a braiding machine. The intermediate body of the hose is put in a heater and the rubber layer 13 of the inner tube is heated under the temp. condition where it is not completely vulcanized and the reinforcing fiber 17 is yarn-shrunk. The rubber material of the rubber layer 13 of the inner tube is expanded, whereas the reinforcement fiber 17 is yarn-shrinked, and blown-off rubber part 19 is protruded out. When the intermediate body of the hose protruded out of the blown-off rubber part 19 is passed through a refrigerator 21, the blown-off rubber rubber part 19 becomes brittle under the refrigeration. The blown-off rubber part 19 which is refrigerated to a temp. less than the embrittlement point is scraped away with a scraper dice 29 for the blown-off rubber part. When the scraper dice 29 for the blown-off rubber is set at an exit of a cylinder 23, the scraping operation for elimination of the blown-off rubber can be performed continuously. The intermediate body of the hose is covered with a rubber layer 31 for anouther tube with an extruder. Thereafter the rubber hose is formed completely when the mandrel 11 is drawn out after the vulcanization treatment.

Description

[Detailed description of the invention] <Field of industrial application> The present invention relates to a high-pressure rubber hose (hereinafter abbreviated as "rubber hose").
and its manufacturing method. Examples of rubber hoses include air conditioner hoses, power steering hoses, clutch hoses, and brake hoses, and such rubber hoses are formed with a high-density fiber reinforced layer.

<Prior Art> Conventionally, as an example of the above-mentioned type of rubber hose, an air conditioner hose l has an inner tube rubber layer 2 (for example, NBR) as shown in FIG.
), a fiber reinforcement layer 3 (hereinafter abbreviated as "reinforcement layer"; for example, made of polyester fiber), and an outer tube rubber layer 4 (for example, EPDM)
And such a rubber hose 1 is composed of
It is formed by extruding the inner tube rubber layer 2 onto a mandrel (not shown), driving the reinforcing layer 3 at high density, and then extruding the outer tube rubber layer 4. At this time, reinforcement FM with large yarn shrinkage
If the reinforcing layer 3 is formed with high density due to m, the threads of the reinforcing layer 3 will shrink during vulcanization, so the rubber material of the inner tube rubber layer 2 will blow out from the tread of the reinforcing layer 3, and the rubber hose 1 will be exposed to the outside of the rubber hose 1. The surface may become wart-like. Therefore, (i) raw hose (referring to unvulcanized hose) before vulcanization.
Wrap a tape-like cloth around the outer tube rubber layer 4 and vulcanize it (
(See Japanese Patent Publication No. 59-29421, etc.).

(ii) Place the raw hose into the mold and press vulcanize.

(iii) Perform lead vulcanization (see Japanese Patent Publication No. 17689/1989, etc.).

The outer surface of the raw hose was restrained using means such as the above, and the blown rubber material of the inner tube rubber layer 2 was used to prevent the above-mentioned bumps from forming on the outer surface of the outer tube rubber layer 4.

In addition, as a technology related to the present invention, Japanese Patent Publication No. 51-503
There is a method for manufacturing a rubber hose described in JP 4.52-33154 and the like.

<Problems to be Solved by the Invention> It is true that by using the means (i) to (iii) above, a rubber hose with a smooth outer surface can be obtained.

However, there were the following problems.

(a) It takes time and effort to restrain the outer surface of a green hose with tape wrapping (i) or a mold (ii), and the productivity of the hose decreases. Further, when the outer surface of the raw hose is restrained by tape wrapping (i), spiral stripes 5 are formed on the outer surface as shown in FIG. These stripes 5 reduce the tightening force when the hose 1 is tightened with a band or the like, and are not preferable from the standpoint of hose design.

(b) If lead-covered vulcanization (i-hole) is performed, countermeasures against lead pollution will be required.

Means for Solving the Problems The present inventor has conducted extensive research in an attempt to solve these problems, and has found that when the reinforcing layer shrinks during vulcanization, the rubber material of the inner tube rubber layer The present invention was completed by paying attention to the problem of blowing out from the eyes.

That is, a reinforcing layer is formed on the inner tube rubber layer, the rubber material of the inner tube rubber layer is blown out from the bottom of the reinforcing layer by heating, the blown rubber part is cooled and hardened, and an external force is applied to cool the blown out tube. The above-mentioned problems are solved by removing the rubber part, covering the outer tube rubber layer, and vulcanizing to manufacture a rubber hose (Example) The present invention will be explained in detail below based on an example.

This example is a method for manufacturing an air conditioner hose, and each step will be explained below with reference to the drawings.

(Step I; Fig. 1) Inner tube rubber layer 13 (for example, NBR) is extruded onto metal mandrel 11 using an ordinary extruder (Step ①; Second
Figure) A reinforcing IJ 15 is formed on the inner tube rubber layer 13 using a braiding machine. This reinforcing layer 15 is implanted with high density (the reinforcing edge m17 of the reinforcing layer 15 is larger in area than the inner tube rubber layer 13 exposed through the grooves of the reinforcing layer) in order to maintain high pressure durability.

Examples of the reinforcing fibers 17 include polyester, polyamide, and rayon, which shrink by 2 to 10% under the heating conditions in step (m) below.

Further, the reinforcing layer 15 may be formed by spirally forming the reinforcing fibers 17 into two layers so as to cross each other.

(Step ■; Fig. 3.7) Next, put the inner tube of the hose from Step 11 above into a heater,
The inner tube rubber layer 13 is not completely vulcanized and the reinforcing fibers 17
The yarn is heated at a temperature that causes the yarn to shrink.

For example, the rubber material of the inner tube rubber layer 13 is NBR, and the reinforcing fiber 1
If 7 is polyester, the temperature is 160°C.

What is necessary is just to heat under conditions of 15 to 10 minutes.

When subjected to the heat treatment, the rubber material of the inner tube rubber layer 13 softens and expands in volume, while the reinforcing fibers 17 shrink, so the reinforcing layer 15 bites into the inner tube rubber layer 13. Therefore, as shown in FIG. 7 (cross-sectional view along the line ■-■ in FIG. 3), the inner tube rubber layer 1
The rubber material No. 3 is blown out from the bottom of the reinforcing layer 15. This rubber material is the blowout rubber part 19 in the figure.
It is.

Note that the reason why the inner tube rubber layer 13 is left in a semi-vulcanized state is to allow vulcanization and adhesion to the outer tube rubber layer later, and the vulcanization of the inner tube rubber layer 13 may be completed in this step. .

(Step ①; Fig. 4.8) This step is a step in which the above-mentioned blown rubber portion 19 is removed by a so-called "frozen scraper".

A hose intermediate body in which the rubber material of the inner tube rubber layer 13 is blown out from the grooves of the reinforcing layer 15 is passed through the refrigeration device 21. This frozen type Fa 21 is a cylindrical member made of a porous material (eg, unglazed).

It has an inner diameter through which a hose intermediate body with a protruding rubber part 19 can be inserted. The refrigerating liquid supply pipe 25 is connected to a refrigerating liquid tank (not shown), and supplies a refrigerating liquid (e.g., liquid N2, fluorohydrocarbon: anything below the embrittlement temperature of the rubber material of the inner tube rubber) to a porous material. A certain refrigeration device i!
t21 and permeates into its peripheral wall, thereby cooling the temperature of the refrigeration device 21 to below the embrittlement temperature of the rubber material of the inner tube rubber layer 13.

Then, when the hose intermediate from which the blowing rubber part 19 protrudes is inserted into the freezing mold 2121, the blowing rubber part 19
For example, the freezing device 2
1 to -50° C., the blown rubber portion 19 can be made brittle in about 5 to 20 seconds. In addition, since the cooling time is short, there is no adverse effect on the inner tube rubber layer 13 or the reinforcing layer 15. Also, without using the above-mentioned refrigeration device 21, the cooling time can be directly applied to the blowing rubber part 19 of the hose intermediate body. You may also spray it with freezing liquid.

Next, the blown rubber part 19 that has been frozen to below the embrittlement temperature is scraped off using a blown rubber part removal die 29.
For example, it is possible to easily remove the blown rubber portion 19 by squeezing, etc., but it is preferable to dispose the blown rubber portion removing die 29 at the outlet of the cylindrical body 23 because the removal operation of the blown rubber portion 19 can be performed continuously.

When "frozen scraping" is performed in this way, as shown in FIG. 8 (cross-sectional view along the line ■-■ in FIG. 4), the blown rubber Section 19 will be folded and removed.

(Process V; Fig. 5) Fig. 5 shows the hose intermediate body from which the blown rubber portion 19 has been removed. If necessary, an adhesive such as RFL is applied to this hose intermediate body by an adhesive applicator. Ru.

(Step ①; FIG. 6) In this step, the hose intermediate shown in FIG. 5 is covered with an outer tube rubber layer 31 (for example, made of EPDM) using an extruder. Then, a vulcanization treatment (eg, 160° C., 50 minutes) is performed, and the mandrel 11 is pulled out to complete the rubber hose.

Of course, since the yarn shrinkage of the reinforcing fibers 17 has been completed, the rubber material of the inner tube rubber layer 13 will not blow out during the above-mentioned vulcanization to form a bulge-like protuberance on the outer surface of the hose.

<Effects of the Invention> As explained above, the present invention includes forming a reinforcing layer, then blowing out the rubber material of the inner tube rubber layer from the grooves of the reinforcing layer,
This method of manufacturing a rubber hose involves removing this blown rubber part with a so-called "freezer removal", covering the outer tube rubber layer, and vulcanizing it.
Compared to the conventional method in which vulcanization is performed while restraining the outer surface of a green hose using a rubber hose, it requires less time and effort, and improves the productivity of rubber hoses.

Furthermore, lead pollution, unlike leaded vulcanization (II+), does not occur.

Furthermore, the spaces between the reinforcing layers are filled with the blown rubber material of the inner tube rubber layer, at least up to the narrowest portion thereof. Therefore, when molding the outer tube rubber layer, air is less likely to accumulate between the grooves of the reinforcing layer, and a rubber hose with strong interlayer adhesion, that is, with high durability, is produced.

[Brief explanation of drawings]

Figures 1 to 8 show examples of the present invention, Figures 1 to 6 are diagrams showing the state of the rubber hose in each manufacturing process, Figure 7 is a sectional view taken along the line ■-■ in Figure 3, and Figure 8. is a cross-sectional view along the line ■--■ in FIG. 4, and FIG. 9 is a perspective view of a rubber hose manufactured by a conventional manufacturing method. 13... Inner tube rubber layer. 15... (Fiber In) Reinforcement layer. 19...Blowout rubber part, 31 Outside tube rubber layer. Patent application Toyoda Gosei Co., Ltd. Figure 9

Claims (1)

[Claims] A fiber reinforced layer is formed on the inner tube rubber layer, the rubber material of the inner tube rubber layer is blown out from the grooves of the fiber reinforced layer by heating, and the blown rubber portion is cooled and hardened, A method for manufacturing a high-pressure rubber hose, which comprises: removing the cooled blown rubber portion by applying an external force, covering the outer tube rubber layer, and vulcanizing it.