JPH0773890B2 - Manufacturing method of resin / rubber composite curved hose - Google Patents

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 resin / rubber composite bent hose having a resin layer on its inner surface and bent into a predetermined shape.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a bent rubber hose, a hose is manufactured by inserting a bent mandrel into a hollow inside of an unvulcanized rubber hose preformed into a straight shape by extrusion or the like. Of the unvulcanized rubber hose 100 preformed in a straight shape as shown in FIG. 5, or a method of vulcanizing the unvulcanized rubber hose while maintaining the shape of the mandrel. There is known a method of setting in the outer frame mold 102 without using the above and holding it in a bent shape, and then heating and vulcanizing it in that state.

By the way, in recent years, a resin / rubber composite hose having a resin layer having excellent characteristics such as refrigerant permeation resistance on the inner surface has been used in a hose for transporting a refrigerant. When a straight unvulcanized product is set in the outer frame mold 102 to vulcanize and mold into a predetermined curved shape, a large number of wrinkles are generated in the inner surface resin layer having poor elasticity. There is a problem of having an adverse effect.

As a method of preventing this, as shown in FIG. 6, a flexible mandrel 104 is inserted and set in the outer frame mold 102 to be bent and deformed into a predetermined shape and the shape is maintained. A method such as vulcanization molding may be considered.

By the way, in this method, the mandrel 1
When 04 is inserted into the unvulcanized composite hose 106 or when the mandrel 104 is pulled out from the hose 106 after vulcanization, a constant gap is provided between the outer surface of the mandrel 104 and the inner surface of the hose 106 in order to ensure insertability and withdrawability. It is necessary to secure a clearance larger than the size.

However, if there is a clearance of a certain size or more between the outer surface of the mandrel 104 and the inner surface of the hose 106, when the unvulcanized hose is bent and deformed while the mandrel 104 is inserted, the clearance is based on the clearance. There arises a problem that the generation of wrinkles 110 in the resin layer 108 on the inner surface of the hose cannot be sufficiently suppressed.

This is the outer surface of the mandrel 104 and the hose 10.
6 It is based on the fact that the clearance between the inner surface and the inner surface is large. Therefore, if this clearance is made small, it is possible to prevent the generation of wrinkles. However, as mentioned above, this clearance is made smaller than a certain value. If this happens, the work of inserting and removing the mandrel 104 from the hose 106 becomes extremely difficult.

[0008]

The invention of the present application has been made for the purpose of solving such a problem.
Thus, the first invention of the present application is a resin which has a resin layer on the inner surface and a rubber layer on the outer periphery of the resin layer, and which is bent into a predetermined shape.
A method of manufacturing a rubber composite curved hose, comprising: (a) molding the resin layer, coating the resin layer with unvulcanized rubber and preforming the material into a straight shape of a predetermined length. A step of inserting a flexible and heat-expandable mandrel into the hollow inside of the unvulcanized composite hose, and (b) heating at least the mandrel with the mandrel inserted in the unvulcanized composite hose. A heat treatment step for expanding and expanding the mandrel by (a) and (c) a step of bending and deforming the unvulcanized composite hose together with the mandrel after the heat treatment step and setting the mandrel in a predetermined constraining type. Vulcanizing and molding the unvulcanized composite hose in a restrained state by the restraint mold (claim 1). Here, as the mandrel, a polyester mandrel having a large thermal expansion amount can be preferably used.

Another aspect of the present invention is a resin which has a resin layer on its inner surface, a rubber layer on the outer peripheral side of the resin layer, and a reinforcing thread layer in the middle of the cross section of the rubber layer. .A method for manufacturing a rubber composite bending hose, which comprises (a)
After molding the resin layer, the outer periphery of the resin layer is covered with unvulcanized rubber and preformed in a straight shape to form a flexible mandrel inside the hollow of an unvulcanized composite hose of a predetermined length. And (b) applying heat to the unvulcanized composite hose while the mandrel is inserted into the unvulcanized composite hose.
A heat treatment step of reducing the diameter of the mandrel based on the contracting action of the reinforcing yarn, and (c) a step of bending and deforming the unvulcanized composite hose together with the mandrel after the heat treatment step and setting it in a predetermined constraining type. And (d) a step of vulcanizing and molding the unvulcanized composite hose in a restrained state by the restraint die (claim 2). In the present invention, it is desirable to use a fiber reinforcing yarn such as polyester or vinylon as the reinforcing yarn.

Still another invention of the present application is the manufacturing method according to claim 1, wherein the mandrel is reduced in diameter by cooling after the vulcanization molding, whereby the outer surface of the mandrel and the inner surface of the vulcanization molding hose are formed. It is characterized in that a clearance for extracting the mandrel is provided therebetween (claim 3). In the present invention, it is desirable that the mandrel is naturally cooled and the lower limit of the cooling temperature is 50 to 60 ° C. 5
When cooled to below 0 ° C, the mandrel becomes hard and difficult to pull out.

Still another invention of the present application is to provide claims 1 to 3.
In the manufacturing method of the above, when the mandrel is inserted, a gap between the outer surface of the mandrel and the inner surface of the unvulcanized composite hose is 0.2 to
The outer diameter of the mandrel and the inner diameter of the unvulcanized composite hose are determined so that a clearance of 1.0 mm is produced (claim 4).

Still another invention of the present application is to claim 1 to 4.
In the manufacturing method, the clearance between the outer surface of the mandrel and the inner surface of the composite hose is 0.2 mm or less when the mandrel is expanded and / or the unvulcanized composite hose is reduced in diameter by the heat treatment. It is characterized in that the condition is determined so that (Claim 5).

Still another invention of the present application is to claim 1 to 5.
In the manufacturing method described in (1), the resin / rubber composite bent hose is a hose for transporting a refrigerant (claim 6).

Still another invention of the present application is to claim 1 to 6.
In the above manufacturing method, the resin layer on the inner surface of the hose is a polyamide resin layer (claim 7).

[0015]

As described above, according to the first aspect of the invention, the mandrel is made of a heat-expandable material, and the mandrel is inserted into the straight preformed unvulcanized composite hose and then vulcanized. Heat treatment is applied before the process,
Thus, the mandrel is expanded and expanded.

According to this method, the clearance between the outer surface of the mandrel and the inner surface of the hose can be reduced to a predetermined value or less by the expansion of the diameter of the mandrel during the heat treatment, and the inner surface can be bent during the subsequent bending deformation and vulcanization. It is possible to prevent wrinkles from occurring in the resin layer.

As a result, it is possible to prevent deterioration of the hose quality and characteristics due to wrinkles.

Here, the clearance means the total amount of the gap between the outer surface of the mandrel and the inner surface of the hose in the cross section including the axis.

On the other hand, according to the present invention, since a certain clearance or more can be secured when inserting the mandrel into the unvulcanized composite hose, it is easy to insert the mandrel into the unvulcanized composite hose. Can be done.

The invention of claim 2 relates to a hose having a reinforcing thread layer in the middle of the cross section, and the heat shrinkability of this reinforcing thread layer is utilized to reduce the inner diameter of the hose during heat treatment to reduce the outer diameter of the mandrel. It is characterized in that the clearance between and is small.

Also in this method, the unvulcanized hose and mandrel can be bent and deformed by vulcanization after the clearance between the outer surface of the mandrel and the inner surface of the hose is reduced to a certain value or less by heat treatment, and the resin layer on the inner surface can be deformed. It is possible to prevent wrinkles from being generated.

Since the reduction of the clearance is performed after the mandrel is inserted into the unvulcanized composite hose as in the case of the first aspect of the invention, when the mandrel is inserted into the unvulcanized composite hose, the clearance is not less than a certain value. Can be secured, and good mandrel insertability can be secured.

According to the third aspect of the present invention, the diameter of the mandrel is reduced by cooling after the vulcanization molding, so that the mandrel can be easily taken out from the inside of the hose after the vulcanization molding.

According to the fourth aspect of the present invention, when the mandrel is inserted, the distance between the outer surface of the mandrel and the inner surface of the hose is 0.2 mm or more.
The clearance is set to be 0 mm or less.

According to the research conducted by the present inventor, naturally, the larger the clearance, the better the mandrel insertability, but it was confirmed that the provisional mandrel insertability can be secured by setting the clearance to 0.2 mm or more. The present invention has been made based on this finding.

However, if it exceeds 1.0 mm, the clearance between the mandrel and / or the hose cannot be made sufficiently small when the mandrel or / and the hose is expanded / reduced in diameter later.

According to the fifth aspect of the invention, the clearance between the mandrel and the hose is reduced to 0.2 mm or less by expanding the diameter of the mandrel or / and decreasing the diameter of the hose during heat treatment.

The present invention is based on a study by the present inventor that the effect of suppressing wrinkling of the inner surface resin layer is dramatically improved when the clearance is 0.2 mm, that is, when the clearance is 0.2 mm or less. Based on knowledge.

The invention of the present application is applicable to hoses for various purposes, but it is particularly effective when applied to a refrigerant transport hose (claim 6). Can be suitably used for those having a polyamide resin layer.

[0030]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 2, reference numeral 10 denotes a resin / rubber composite bent hose (here, a hose for transporting a refrigerant), which has a predetermined bay-bent shape.

As shown in FIG. 2B, the hose 10 has an outer rubber layer 12 and an intermediate rubber layer 14 having a cross-sectional shape.
And the reinforcing yarn layer 16 between them and the resin layer 18 on the inner surface form a laminated structure.

In this example, EPD is used as the outer rubber layer 12.
M is NBR (or butyl rubber) as an intermediate rubber layer,
Polyester fiber is used as the reinforcing thread layer 16, and polyamide resin is used as the resin layer 18 on the inner surface.

The thickness of each of these layers is such that the outer rubber layer 12 is 1.7 mm, the inner rubber layer 14 is 1.0 mm, the inner resin layer 18 is 150 μm, and the hose inner diameter is 12.0.
mmφ and the outer diameter is 19.5 mmφ.

FIG. 3 shows an example of a method for manufacturing the resin / rubber composite bent hose. As shown in the figure, in the method of this example, the long resin layer 18 is extruded and then the intermediate rubber layer 14 is extruded on the outer periphery of the resin layer 18.

Further, a fiber reinforcing yarn is braided on the outer periphery of the intermediate rubber layer 14 to form a reinforcing yarn layer 16, and the outer rubber layer 12 is extrusion-molded on the outer periphery of the reinforcing yarn layer 16 to form a long non-woven fabric. A vulcanized resin / rubber composite hose is formed and cut into a predetermined length to preform an unvulcanized resin / rubber composite hose 10a having a straight shape and a predetermined length.

Next, this is subjected to a treatment (for example, 135 ° C. × 20 minutes) for imparting a certain shape retention property, and then,
As shown in FIG. II, a heat-expandable mandrel 20 made of straight Teflon, polymethylpentene, rubber, preferably polyester, having a straight shape is inserted into the unvulcanized composite hose 10a. To do.

Here, the mandrel 20 has such a thickness that a clearance of 0.2 to 1.0 mm is generated between the outer surface of the mandrel 20 and the inner surface of the unvulcanized composite hose 10a. By ensuring this clearance, the mandrel 20 can be easily inserted inside the hose 10a.

After inserting the mandrel 20 into the unvulcanized composite hose 10a, the mandrel 20 is then placed in a heated air chamber 24 indicated by a chain double-dashed line as shown in FIG. Heat treatment is performed.

This heat treatment reduces the inner diameter of the hose based on the heat-shrinking action of the reinforcing yarn layer 16 and at the same time expands and expands the mandrel 20 to reduce the clearance between them to a predetermined value or less. belongs to. The degree of clearance reduction at this time depends on conditions such as heating temperature and holding time.

FIG. 4 shows this state. As shown in the figure, the higher the heating temperature and the longer the holding time, the larger the expansion and expansion amount of the mandrel and the decrease in the inner diameter of the hose.

This heat treatment is performed so that the hose is not vulcanized and the inner diameters of the mandrel and the hose are expanded or reduced in a sufficient amount, that is, the clearance between them is sufficiently small. It is necessary to select the conditions so that In this example, the heat treatment is performed in a heated air chamber at 150 ° C. for 40 minutes. Incidentally, as the heating method, it is possible to adopt another heating method.

By the above heat treatment, the hose 10
a When the clearance between the inner surface and the outer surface of the mandrel 20 becomes sufficiently small (here, 0 to 0.2 mm), then
As shown in IV, with the mandrel 20 inserted, the unvulcanized composite hose 10a is set in the outer frame die 22 to be bent and deformed and held in the same shape, and under that state under no pressure (atmospheric pressure). Open vulcanization molding is performed by heating in an air chamber at 170 ° C. for 40 minutes.

After the vulcanization molding process is completed, the hose 10 is taken out from the outer frame mold 22 together with the mandrel 20 as indicated by V. After that, when the hose 10 and the mandrel 20 are naturally cooled to 50 to 60 ° C., the mandrel 20 contracts and a predetermined clearance is generated between the hose 10 and the inner surface of the hose 10. Then, as shown in VI, the mandrel 20 is extracted from the hose 10 after vulcanization.

According to the method of this embodiment, as shown in FIG. 1 (A), the mandrel 20 is secured with sufficient clearance between the mandrel 20 and the inner surface of the unvulcanized composite hose 10a.
While the hose 10a can be inserted inside the hose 10a, during the heat treatment in step III, the inner diameter of the hose 10a is reduced and the diameter of the mandrel 20 is increased, so that the clearance between them is increased as shown in FIG. 1 (B). Can be zero or a very small value.

Therefore, even if the unvulcanized composite hose 10a is bent and vulcanized thereafter, it is possible to prevent wrinkles from being generated in the resin layer 18 on the inner surface, and to provide the composite bent hose 10 of good quality. it can.

The embodiment of the present invention has been described in detail above, but this is merely an example, and the present invention can be applied to a hose having no outer rubber layer and a hose having a plurality of reinforcing thread layers. For example, the present invention can be implemented with various modifications made on the basis of the knowledge of those skilled in the art without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is an explanatory view of an operation in a main step of a method for manufacturing a resin / rubber composite bent hose which is an embodiment of the present invention.

FIG. 2 is an explanatory view of the resin / rubber composite bending hose.

FIG. 3 is an explanatory diagram of steps of the manufacturing method according to the embodiment.

FIG. 4 is a diagram showing a relationship between a condition of a heat treatment process and a clearance reduction amount in FIG.

FIG. 5 is an explanatory view of a conventional method for manufacturing a rubber hose.

FIG. 6 is an explanatory view of a defect in manufacturing a resin / rubber composite bent hose.

[Explanation of symbols]

10 Resin / Rubber Composite Bent Hose 10a Unvulcanized Composite Hose 16 Reinforcing Thread Layer 18 Resin Layer 20 Mandrel 22 Outer Frame Type

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29K 105: 24 B29L 23:00

Claims (7)

[Claims] 1. A method for producing a resin-rubber composite curved hose having a resin layer on the inner surface and a rubber layer on the outer periphery of the resin layer, the resin-rubber composite bending hose being formed into a predetermined shape. Then, a flexible and thermally expansive mandrel is provided inside the hollow of an unvulcanized composite hose having a predetermined length, which is preformed into a straight shape by coating the unvulcanized rubber on the outer periphery of the resin layer. And (b) a heat treatment step of expanding at least the mandrel by heating the mandrel in a state where the mandrel is inserted in the unvulcanized composite hose, and (c) the heat treatment step after the heat treatment step. A step of bending and deforming the vulcanized composite hose together with the mandrel to set it in a predetermined constraining type; and (d) vulcanizing and molding the unvulcanized composite hose in a constrained state by the constraining type. Manufacturing method of resin / rubber composite curved hose characterized by . 2. A resin-rubber composite bent horn bent in a predetermined shape, having a resin layer on the inner surface, a rubber layer on the outer peripheral side of the resin layer, and a reinforcing thread layer in the middle of the cross section of the rubber layer. (A) After molding the resin layer, the outer periphery of the resin layer is coated with unvulcanized rubber and preformed in a straight shape to give a predetermined length of unvulcanized composite ho A step of inserting a flexible mandrel into the hollow inside of the cloth; and (b) applying heat to the unvulcanized composite hose with the mandrel inserted therein to reinforce the unvulcanized composite hose. A heat treatment step of reducing the diameter based on the shrinking action of the yarn, and (c) a step of bending and deforming the unvulcanized composite hose together with the mandrel after the heat treatment step and setting it in a predetermined constraining type. Vulcanizing and molding the unvulcanized composite hose in a restrained state by a restraint mold. Method for producing a resin-rubber composite bending hose and said. 3. The manufacturing method according to claim 1, wherein the mandrel is reduced in diameter by cooling after the vulcanization molding so that the mandrel is removed between the outer surface of the mandrel and the inner surface of the vulcanization molding hose. A method for manufacturing a resin / rubber composite bent hose characterized by producing a clearance. 4. The manufacturing method according to claim 1, wherein when the mandrel is inserted, a clearance of 0.2 to 1.0 mm is formed between the outer surface of the mandrel and the inner surface of the unvulcanized composite hose. A method for producing a resin / rubber composite curved hose, which comprises determining an outer diameter of a mandrel and an inner diameter of the unvulcanized composite hose. 5. The manufacturing method according to any one of claims 1 to 4, wherein when the mandrel is expanded and / or the unvulcanized composite hose is reduced in diameter by the heat treatment, the mandrel outer surface and the composite hose inner surface are formed. A method for producing a resin / rubber composite curved hose, characterized in that the conditions are determined so that the clearance between the two is 0.2 mm or less. 6. The method of manufacturing a resin / rubber composite bent hose according to claim 1, wherein the resin / rubber composite bent hose is a hose for transporting a refrigerant. 7. The method of manufacturing a resin / rubber composite bent hose according to claim 1, wherein the resin layer on the inner surface of the hose is a polyamide resin layer.