JPH0216039A - Manufacture of branch hose with reinforcing layer - Google Patents

Abstract

PURPOSE:To avoid the increase of rigidity and weight, and to improve appearance and quality by forming a netted reinforcing layer onto the surface of an inner tube section with a branch section by a molten resin, shaping a skin section onto the surface of the reinforcing layer, vulcanizing the inner tube section and the skin section and integrally bonding the inner tube section and the skin section together with the reinforcing layer. CONSTITUTION:The inner tube 1 of a three-way hose is formed through injection molding by using an EPDM rubber, and arranged into a reinforcing layer molding die 3 as an inner core 2 is left as it is inserted into a central hole, a molten nylon resin is injected into a cavity 31 chopped to a mesh grooved shape from a plurality of filler holes 30, and a netted reinforcing layer 4 is shaped onto the surface of the inner tube section 1. The cavity 31 is formed so as to be spread toward a branch section, and the density of the branch section is increased in the reinforcing layer 4. The inner tube section 1 is disposed into the molding die, and a skin section 5 is molded through injection molding from the EPDM rubber. The whole is molded, released from the die, charged into a vulcanizer as the inner core 2 is left as it is inserted, and vulcanized integrally.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a branch hose such as a three-way hose, and more particularly to a method for manufacturing a branch hose having a reinforcing layer in the intermediate layer.

[Prior Art] A large number of devices are installed in the engine room of an automobile, and efficient use of the installation space is desired. For example, radiator hoses require multiple hoses, such as a hose that connects the radiator and the engine, and a coiled hose that connects the radiator and the air conditioner, which requires a large installation space. Therefore, the arrangement of other devices was limited, and the degree of freedom was small. Therefore, in recent years, the use of branch hoses consisting of a main hose and an auxiliary hose branched from the main hose has been considered. If such a branch hose is used, the installation space can be significantly reduced.

FIG. 4 shows a sectional view of a conventional branch hose. This branch hose includes a main hose 100, a sub hose 200 branched from the main hose 100, and a main hose 100 and sub hose 2.
00, and a bonding rubber 300 that covers the branched portion of 00. Conventionally, this branch hose manufacturing method involves drilling a branch hole in an unvulcanized main hose 100, and covering the branch hole with an unvulcanized auxiliary hose 200 whose tip is enlarged in diameter into a trumpet shape. After that, the sub hose 200 and the main hose 100 are placed in a mold together with the mandrel 500.

Then, bonding rubber 300 made of unvulcanized rubber is coated and molded to cover the inner and outer surfaces of the branch part, and the whole is further vulcanized to be integrally bonded (US Pat. No. 4,589,623). However, in the case of a hose having a reinforcing layer in which reinforcing threads are braided in the intermediate layer, this manufacturing method requires the reinforcing layer 400 of the main hose 100 and the sub-hose 200 as shown in FIG.
is in a divided state. As a result, there has been a problem in that the strength of the branch part is weaker than other parts. Therefore, although the thickness of the bonding rubber 300 is increased to give it strength, the rigidity of that part increases, making it difficult to handle, and it is also heavy and does not have a good appearance.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and its technical problem is to make the reinforcing layers of the main hose and the auxiliary hose integral and continuous. .

[Means for Solving the Problems] The method for manufacturing a branch hose with a reinforcing layer of the present invention includes an inner tube molding step of forming an inner tube portion having a branch portion from unvulcanized rubber, and a step of molding the inner tube portion in a mold. A reinforcing layer molding process in which a net-like reinforcing layer is formed on the inner tube surface using resin, and an inner tube section with the reinforcing layer is placed in a mold and an outer covering section is formed on the surface using unvulcanized rubber. It is characterized by comprising the main molding step and the vulcanization step of vulcanizing the inner tube portion and the outer covering portion and integrally bonding them together with the reinforcing layer.

The inner tube forming step is a step of forming an inner tube portion having a branch portion from unvulcanized rubber. It is convenient to form a cylindrical body such as a hose by extrusion molding, but if it has a branched part, it is not practical to mold it all at once by extrusion molding. Therefore, the main pipe part and the sub pipe part can be formed by extrusion molding, and the sub pipe part can be formed by providing a branch hole in the main pipe part and then inserting the sub pipe part.

Further, the inner part having a branch part can also be integrally formed by compression molding, injection molding, or the like. The materials for this inner tube include natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), and butyl rubber (I).
Various conventional rubbers such as nitrile rubber (IR), nitrile rubber (NBR), and ethylene bropyrene rubber (EP D'M) can be used.

The greatest feature of the present invention is the reinforcing layer forming step.

In this reinforcing layer forming step, a net-like reinforcing layer is formed on the surface of the inner tube portion using molten resin. That is, the conventional reinforcement layer was formed by braiding reinforcing threads, but in the present invention, the reinforcement layer is formed by molding. Thereby, a continuous reinforcing layer can be easily formed even at the branch portion. Note that although the density of the net-like reinforcing layer may be uniform throughout, it is desirable to increase the density at branch portions where stress tends to concentrate. Ordinary injection molding or the like can be used to form this reinforcing layer.

The jacket molding step is a process in which the inner tube portion having the reinforcing layer obtained as described above is placed in a mold, and an outer jacket portion is formed from unvulcanized rubber on the surface thereof. This molding step can also be carried out by ordinary injection molding. Moreover, the material used can be the same various rubbers as the inner tube part, and may be the same type as the inner tube part or a different type of rubber.

Note that it is desirable to use a rubber that has good compatibility with the rubber constituting the inner tube portion. In this way, the unvulcanized rubber of the outer sheath and the unvulcanized rubber of the inner tube will come into contact through the mesh of the net during molding of the outer sheath, and will be solidified as a unit in the next vulcanization process. Because they are bonded together, a hose with even greater strength can be obtained.

The vulcanization process is a process of vulcanizing the inner tube part and the outer cover part.

As a result, the inner tube part and the outer jacket part are integrally connected, and furthermore, the reinforcing layer is also integrally connected.

This vulcanization step may be performed within the mold, or may be vulcanized in a vulcanization can after being released from the mold. Note that during this vulcanization, a mandrel is usually inserted to ensure accuracy in the inner diameter and outer shape of the hose hole. It is also preferable that this mandrel is inserted from the initial inner tube forming process, and that the welding process and outer jacket forming process are also performed with the mandrel inside.

[Operations and Effects of the Invention] Accordingly, in the manufacturing method of the present invention, since the reinforcing layer is formed by molding in the reinforcing layer forming step, a continuous reinforcing layer can be formed even at the branch portion.

Therefore, in the branched hose obtained by the manufacturing method of the present invention, the reinforcing layer is continuous even at the branched portion, and therefore has sufficient strength. Moreover, such a reinforcing layer can be formed very easily. Therefore, the branched hose obtained by the manufacturing method of the present invention has excellent strength even without the need for bonding rubber as in conventional branched hoses, so increases in rigidity and weight can be avoided, and the appearance quality is also excellent.

[Example] Hereinafter, the present invention will be explained in detail with reference to Examples. In this embodiment, the present invention is applied to a radiator hose for an automobile.

(Inner tube forming process) Using EPDM rubber, the inner tube part 1 of the 3-way hose is formed by injection molding.The obtained inner tube part 1 is in an unvulcanized state, and the inner core 2 is in the center hole. It has been inserted.

(Reinforcement layer forming process) Next, as shown in FIG.
Molten nylon resin is injected into a cavity 31 carved into a more mesh groove shape to form the mold.

As a result, a net-like reinforcing layer 4 is formed on the surface of the inner information part 1. Incidentally, the cavities 31 are formed in large numbers at the branching portions, and the reinforcing layer 4 has a high density at the branching portions.

(Outer jacket molding process) Next, the inner tube part 1 with the reinforcing layer 4 is placed in the mold, and the EP
The outer covering portion 5 is molded from DM rubber by injection molding.

(Vulcanization process) After the outer cover part 5 is molded, it is released from the mold, and with the inner core 2 inserted, it is put into a vulcanizing can and the whole is vulcanized integrally.

A cross-sectional view of the main part of the obtained branched hose is shown in FIG. Third
As shown in the figure, the branch hose obtained in this example consists of an inner pipe section 1, an outer covering section 5, and a reinforcing layer 4. The reinforcing layer 4 is not broken even at the branched portion, but is continuous, and has excellent strength.

Furthermore, there is no need for bonding rubber on the outer peripheral surface, resulting in excellent appearance quality.

[Brief explanation of the drawing]

1 to 3 relate to a manufacturing method of an embodiment of the present invention,
Fig. 1 is a cross-sectional view showing the state in which the reinforcing layer forming process is being performed, Fig. 2 is a perspective view of the inner tube portion on which the reinforcing layer is formed, and Fig. 3
The figure is a sectional view of the main part of the obtained branch hose. FIG. 4 is a sectional view of a branch hose manufactured by a conventional manufacturing method. 1... Inner tube 2... Inner core 3... Reinforcement layer molding mold 4... Reinforcement layer 5... Outer covering portion 30...
Inlet 31... Cavity Figure 1 Patent applicant Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] (1) An inner tube molding process in which an inner tube portion with a branch portion is formed from unvulcanized rubber, and the inner tube portion is placed in a mold and a net-like reinforcing layer is formed on the surface of the inner tube portion using resin. a reinforcing layer molding step; a main molding step in which the inner tube portion having the reinforcing layer is placed in a mold and an outer covering portion made of unvulcanized rubber is formed on the surface thereof; and the inner tube portion and the outer covering portion are A method for manufacturing a branch hose having a reinforcing layer, comprising a vulcanizing step of vulcanizing and integrally bonding the reinforcing layer.