JPS6011629B2 - Hose manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a hose suitable for use as fuel piping rubber, and more particularly to a method for manufacturing a hose whose inner surface is covered with a coating of fluorine-based Z rubber.

In general, fuel hoses for gasoline engines are required to have resistance to high aromatic content gasoline, degraded gasoline (sour gasoline), ethanol-added gasoline, etc., and heat resistance to high temperature fluids such as air, water, fuel oil, mineral oil, etc. It is well known that a hose whose inner surface is made of fluorine-based rubber is suitable for the purpose of use.

Accordingly, the fluororubber layer forming the inner surface of the hose as described above has been formed by extrusion molding in the same way as the other rubber layers laminated around the outer periphery of this rubber layer.

However, in the extrusion molding method, the thickness of this rubber layer is 20
It was difficult to reduce the temperature to 0 μm or less. However, it has been confirmed that there is no problem in terms of performance as long as the thickness of this rubber layer is at least 50 mm thick. In addition, this fluorine-based rubber is extremely expensive, and if the fluorine-based rubber layer is too thick at low temperatures, the maneuverability will be reduced. There has been a need for a method of manufacturing a hose whose inner surface is covered with a rubber coating.
The object of the present invention is to provide a method for manufacturing a hose that meets the above-mentioned needs.

The gist of this invention is to apply a fluorine-based rubber solution to the surface of the mandrel and dry it to form a film of a predetermined thickness, then to form another rubber layer on the outer periphery of this film by extrusion molding, and after vulcanization, the mandrel is removed. This is a method for manufacturing a hose in which a fluorine rubber coating is formed on the inner surface of the hose.

The configuration of the present invention will be explained below based on the illustrated embodiments.

1 to 7 are explanatory diagrams showing each step of this embodiment in the order shown, and FIG. 1 shows the step of applying a fluorine rubber solution 2 to the surface of a flexible mandrel 3 made of nylon. The mandrel 3 has an outer diameter approximately equal to the inner diameter of the hose, and is formed by connecting four pieces of length. A fluorine-based rubber solution 2 using methyl ethyl ketone as a solvent is stored in the tank 1, and the mandrel 3 is moved into the solution 2 by four metal guide rollers 4 attached to the layer 1, and then exits the tank. After passing through the final guide roller 4, excess fluorine-based rubber solution is removed by a scraper 5, and the fluorine-based rubber solution 2 is evenly applied to the entire circumference of the mandrel 3 to a predetermined thickness. This coated material enters a dryer 6 shown in FIG. While passing through this dryer for about 5 minutes, the temperature was increased to 40o~60℃.
The hot air evaporates the solvent and dries it. The cross-sectional shape of the mandrel 3 when it leaves the dryer 6 is as shown in FIG. 2A, with a fluorine rubber coating 7 having a thickness of 50 cm being formed around the outer periphery of the mandrel 3. The mandrel 3 covered with the fluorocarbon rubber coating 7 enters the extruder 8 shown in FIG. The inner tube layer 9 is formed,
Its cross-sectional shape is as shown in FIG. 3A. Figure 4 shows a reinforcing layer 1 of polyester Z fiber on the outer periphery of the inner tube layer 9.
4 shows the steps for braiding 0 to have the cross-sectional shape shown in FIG. 4A. Then, the reinforcing layer 10 with the striped reinforcing layer 10 enters the next extruder 11, and the two reinforcing layers 10 are separated by the shrimp chlorohydrin rubber supplied to the hopper of this extruder 11, as shown in FIG. 5A. A covering rubber layer 12 having a thickness of 0.6 to 1.5 side is layered on the outer periphery. Then, at the place where the mandrel 3 comes out of the extruder 11, the joint is removed and separated.
The above-mentioned layers formed on the outer periphery are also cut at this point, resulting in a standard length hose of about 4 skins. This fixed-length hose is housed in the vulcanized bonito 13 shown in FIG.
Steam vulcanized. Take out the vulcanized material from the vulcanizer 13, pull out the mandrel 3 as shown in FIG.
The manufacture of the hose 14 is completed. As shown in FIG. 73A, the inner surface of the hose 14 is covered with a fluorocarbon rubber coating having a thickness of 50 mm. If a thick fluorine rubber coating is to be formed on the inner surface of the hose, the process of applying the fluorine rubber solution to the mandrel (Figure 1) and the drying process (Figures 23) may be repeated.

Further, in order to increase the adhesive force between the fluorine rubber coating and the inner tube layer, an adhesive coating step may be included between the drying step (FIG. 2) and the inner tube forming step (FIG. 3).

Although one preferred embodiment of the present invention has been described, it goes without saying that the configuration of the hose can be freely selected without departing from the spirit of the present invention.

According to the method of the present invention, as described above, a fluorine-based rubber solution is applied to the surface of the mandrel, and this is dried to form a fluorine-based rubber film of a desired thickness, and a rubber layer is formed around the outer periphery by extrusion molding. The inner surface of the hose formed by removing the mandrel is covered with a fluorocarbon rubber coating, and the thickness of the coating is extremely small, which cannot be obtained by extrusion molding. Since less expensive fluorine rubber is used, manufacturing costs can be reduced.
Moreover, the fact that this fluororubber layer is thin also has the effect of preventing a decrease in flexibility at low temperatures.

Brief explanatory diagrams of the drawings show examples of the present invention, and FIG. 1 is an explanatory diagram showing the process of applying a fluorine rubber solution to a mandrel, and FIG. 2 is an explanatory diagram showing the process of drying the applied solution. , FIG. 2A is a sectional view showing the state in which the outer periphery of the mandrel is covered with a fluorine rubber coating, and FIG. 3 is an explanatory diagram showing the process of layering the inner tube layer on the outer periphery of the fluorine rubber coating using an extruder. , FIG. 3A is a sectional view showing a state where the outer periphery is covered with the inner tube layer, and FIG. 4 is an explanatory view showing the process of forming a reinforcing layer on the outer periphery of the inner tube layer by braiding.
FIG. 4A is a cross-sectional view showing a state in which the outer periphery is covered with a reinforcing layer, FIG. A cross-sectional view showing a state in which the outer periphery is molded with an outer covering rubber layer, FIG. 6 is an explanatory view showing the process of vulcanizing in the vulcanization column, FIG. 7 is an explanatory view showing the process of removing the mandrel, and FIG. Figure A is a cross-sectional view of the manufactured hose.

2... Fluorine rubber solution, 3... Mandrel, 7...
...Fluorine rubber coating, 9...Inner tube layer.

Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1 Apply fluorine rubber solution to the outer circumferential surface of the mandrel,
This is dried to form a fluorine rubber coating of a predetermined thickness.
A method for producing a hose, which comprises forming another rubber layer on the outer periphery of the coating by extrusion molding, vulcanizing the layer, removing the mandrel, and forming a fluorine-based rubber coating on the inner surface of the hose.