JPH05200854A - Production of molded hose - Google Patents

Abstract

PURPOSE:To produce a molded hose having good appearance with high productivity so as to effectively prevent the generation of wrinkles in the resin layer of a bent part or the flattening of the bent part even in the case of a hose body having a resin layer formed on the inner surface thereof. CONSTITUTION:A flexible mandrel 2 is inserted in a vulcanized hose body 1 cut into a predetermined length to constitute a vulcanized hose assembly 1a. This assembly 1a is introduced into an oven to be heat-treated at predetermined temp. for a predetermined time and fitted in a mold 3a or 3b preliminarily formed in view of a bending return angle after molding to be shaped. The assembly 1a fitted in the mold 3a or 3b is cooled at predetermined temp. for a predetermined time in a cooling process and subsequently demolded from the mold 3a or 3b and the mandrel 2 is pulled out of a molded hose body molded into a predetermined shape to obtain a product molded hose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a molded hose, and more particularly to a method for producing a molded hose for producing a product molded hose having a predetermined shape by heat-treating a vulcanized hose body. Is.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed as a method for molding a rubber hose into a predetermined bend molding hose, but the following method is used for fitting the rubber hose itself into an outer mold. It has been known. (a). A method of inserting a filler or a flexible mandrel into an unvulcanized hose, fitting the mandrel into a predetermined molding die, and vulcanizing by molding. (b). A method of inserting a filler or a flexible mandrel into a semi-vulcanized hose, fitting it into a predetermined molding die, and vulcanizing by molding (JP-A-3-114815, JP-A-3-14815). No. 114816).

[0003]

[Problems to be Solved by the Invention]
In the case of method (a), the rubber hose itself is in an unvulcanized state.
There is a problem that scratches are likely to occur. Also, in the case of the method (b), two vulcanization steps, a semi-vulcanization step and a main vulcanization step, are required, resulting in poor productivity and a vulcanization can or the like at the hose molding site. However, in the case of a hose body having a resin layer on the inner surface, there is a problem that wrinkles occur in the resin layer at the bent portion.

The present invention was devised in view of the above conventional problems. Since the vulcanized rubber hose is used for molding, secondary vulcanization is not required and productivity is improved. A method of manufacturing a molded hose that can be molded without damaging the appearance of the molded hose and can effectively prevent wrinkles in the resin layer at the bent portion even in the case of a hose body having a resin layer on the inner surface. It is intended to provide.

[0005]

In order to achieve the above object, the present invention cuts a long vulcanized hose into a predetermined length according to the purpose of use, and cuts the vulcanized hose body. After inserting a flexible mandrel into the, heat treatment at a predetermined temperature for a predetermined time, the assembly of the vulcanized hose body in which the mandrel in this heated state is inserted, the bending return angle after molding in advance is expected. After fitting the mold into the molded mold, the assembly fitted in the mold is cooled in the cooling process at the specified temperature for the specified time, then the assembly is released from the mold and the mandrel is removed from the molding hose body. Thus, the gist of the present invention is to manufacture a product molding hose having a predetermined shape.

[0006]

The present invention is configured as described above, and uses a thermoplastic resin for the innermost layer and butyl rubber for the middle layer and the outermost layer for vulcanized long hose or innermost layer and outermost layer. A long vulcanized hose made of butyl rubber is cut to a predetermined length according to the purpose of use. And
After inserting the flexible mandrel into the cut vulcanized hose, put it in an oven etc. and heat it at a predetermined temperature for a predetermined time, and bend it into a predetermined shape with the vulcanized hose body and mandrel soft. In this state, the bending return angle after molding is taken into consideration, and the product is fitted into a molded mold and molded.

After that, the vulcanized hose assembly into which the mandrel fitted in the mold is inserted is cooled at a predetermined temperature for a predetermined time in the cooling step, and then the assembly is released from the mold, and the molding hose is further removed. By removing the mandrel from the main body, a product molding hose having a predetermined shape is manufactured. This eliminates the need for secondary vulcanization, which is required in the past, and improves the productivity of the molded hose because the molding process can be omitted.Because a vulcanized hose is used, it can be molded in the molding process as well. The hose can be molded without damaging its appearance, and even in the case of a hose body having a resin layer on the inner surface, the hose can be molded without causing wrinkles in the resin layer at the bent portion.

Further, since the vulcanized hose is molded, the end portion is not deteriorated, cutting is not necessary, and end cutting waste is also eliminated. Next, an outline of the manufacturing process of the molded hose of the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, in step a, a long rubber hose is manufactured in the rubber hose manufacturing process, and this long rubber hose is vulcanized and molded in the vulcanization process of step b to manufacture a straight pipe vulcanized hose ( Step c).

This straight tube vulcanized hose is cut into a predetermined length in the cutting step d to form a hose body 1 as shown in FIG. Then, a vulcanized hose having a flexible mandrel 2 such as rubber or resin inserted into the vulcanized hose body 1 cut into a predetermined length, and the mandrel 2 as shown in FIG. 2 is inserted. Of the assembly 1a. The hose assembly 1a is placed in an oven or the like (not shown) and heat-treated at a predetermined temperature for a predetermined time (step f). It is fitted into the molding die 3a or 3b as shown in FIG.

Thereafter, the vulcanized hose assembly 1a fitted in the molding die (outer mold) 3a or 3b is cooled at a predetermined temperature for a predetermined time in a cooling step (step h), and then the vulcanized hose is removed. The assembly 1a is released from the mold 3a or 3b (step i). Then, the mandrel 2 is pulled out from the molded hose body molded into a predetermined shape (step j), and the product molded hose is completed.

As a result, the conventional secondary vulcanization is not required, and the molding step can be omitted, so that the productivity of the molded hose can be improved, and since the vulcanized hose is used, the step of molding is performed. Also in the case of molding, it is possible to mold without damaging the appearance of the molding hose. FIG. 3 shows the relationship between the bending return angle of the product forming hose and the heating temperature of the constant temperature oven (oven). The heating time is 10 minutes and the heating time is 20 minutes.
The graph shows the bending return angle at a heating time of 30 minutes. As is clear from FIG. 3, if the rubber hoses of the same material are used, the bending return angle becomes smaller as the heating time becomes longer. Therefore, a product hose close to the molding angle preformed on the molding die 3a or 3b can be used. It can be manufactured.

Next, a method for manufacturing a molded hose having a resin layer as the innermost layer (Example 1) and a method for manufacturing a normal molded hose (Example 2) will be described. [Example 1] Molded hose 4a having a resin layer in the innermost layer 5
As shown in FIG. 4, the inner rubber layer 6, the inner rubber layer 6,
The outermost layer 8 is covered via the reinforcing layer 7, and the molded hose 4a configured in this way has 0.18 mm of thermoplastic resin on the inner surface (innermost layer 5) in the molding step of FIG. A rubber hose is manufactured (step a). At this time, the hose has an inner diameter of 15.0 mm and an outer diameter of 23.0 mm, and butyl rubber is used for the intermediate rubber layer 6 and chlorinated butyl rubber is used for the outer surface (outermost layer 8) rubber. This rubber hose was vulcanized in the vulcanization step (step b) at 154 ° C for 60 minutes, and then a straight tube vulcanized hose was manufactured (step c). Cut to mm.

Then, in the cut vulcanized hose body 1,
The flexible mandrel 2 is inserted (step e). In this case, it is desirable that the gap between the vulcanized hose body 1 and the mandrel 2 is 1.0 mm or less in order to prevent wrinkles in the inner resin layer during bending. For a vulcanized hose with a bending radius of 50 mm, 0.2 to 0.5 mm is desirable. The assembly 1a having the mandrel 2 inserted into the vulcanized hose body 1 is heated in an oven (a constant temperature layer) in a heating step.
Heat at ℃ for 20 minutes (step f). Immediately after the heating is completed, the vulcanized hose assembly 1a is fitted into the U-shaped mold 3b having a bending angle of 180 ° as shown in FIG. 2 in the bending step of step g, and then the cooling step of step h. Cool at 10 ℃ for 20 minutes. Then, in step i, the molding hose is removed from the molding die 3b, and in step j, the mandrel 2 is pulled out from the molding hose. The product molding hose thus obtained has a bending angle of 145 ° (bending return angle 19
%), Which is a product molding hose having (%) (step k).

In the molding process as described above, by adjusting the heating conditions in the heating process of step f, product molding hoses having various bending angles can be obtained from the same molding die 3a or 3b. ..
As a specific example thereof, as shown in FIG. 3 described above, for example, a 180 ° U-shaped molding die 3b is subjected to heat treatment in the heating step of step f at 110 ° C. for 10 minutes, and thus is a vulcanized hose. If the body 1 is used and molded under the same conditions, a product molding hose having a bending angle of 90 ° (bending return angle 50%) can be obtained.

If the heat treatment is carried out at 210 ° C. for 30 minutes, the product forming hose having a bending angle of 155 ° (bending return angle 14%) can be obtained. Besides this,
If the bending angle of the forming die 3b is changed and the U-shaped forming die 3b having a bending angle of 220 ° is used, the heating angle of 180 ° (bending angle of 180 ° A product molding hose having a return angle of 18% can be obtained. Since the mandrel 2 is inserted and heated at the time of bending, the product forming hose bent in this way is a good product in which neither flattening of the bent portion nor wrinkling of the resin layer occurs. [Embodiment 2] As shown in FIG. 5, a normal molded hose 4b has a structure in which an innermost rubber 5a is covered with an outermost layer 8a via a reinforcing layer 7a. As the molded hose 4b, an unvulcanized rubber hose having an inner diameter of 15.0 mm and an outer diameter of 23.0 mm is manufactured in the molding step of FIG. The inner rubber 5a and the outer rubber (outermost layer 8a) of this rubber hose are made of butyl rubber having a compression set of 80% at 70 ° C. for 70 hours. After this rubber hose was vulcanized at 154 ° C. for 60 minutes in the vulcanization step (step b), a straight tube vulcanized hose was obtained (step c), and a length of 350% was obtained in the cutting step (step d). Cut to mm. And
The flexible mandrel 2 is inserted into the cut vulcanized hose body 1 (step e). In this case, the gap between the vulcanized hose body 1 and the mandrel 2 is preferably 2.0 mm or less to prevent flattening of the bent portion during bending.

The mandrel 2 is attached to the vulcanized hose body 1 described above.
The assembly 1a in which is inserted is heated in an oven (constant temperature layer) at 190 ° C for 20 minutes (step f). Immediately after the heating is finished, the hose assembly 1a is fitted into the U-shaped mold 3b having a bending angle of 180 ° as shown in FIG. 2 in the bending step of step g, and then 10 ° C. in the cooling step of step h. Cool in 20 minutes. Then step i
The molding hose is removed from the molding die 3b with and the mandrel 2 is pulled out from the molding hose in step j. The product forming hose thus obtained is a product forming hose having a bending angle of 120 ° to 125 ° (bending return angle of 30% to 33%) (step k).

Under the same conditions as above, the inner diameter is 12.6 mm and the outer diameter is 19.7 mm.
mm rubber hose with compression set of 50 at 70 ° C for 70 hours
% Of chlorinated polyethylene (CPE)
Bending angle of 80 ° to 90 ° (bending return angle 50% to 55%)
It becomes a product molding hose having. In these product molding hoses, the mandrel 2 is inserted and heated at the time of bending, so that it is possible to obtain a good molding hose in which flatness does not occur in the bent portion.

The bending return angle of the product molding hose after molding is preferably set to 30% or less.
If it is 0% or more, the bending back angle will not be constant and the product will vary. In this way, product molding hoses can be manufactured without vulcanization for molding, and by adjusting heating conditions and changing the material of hoses, product molding with various bending angles can be manufactured. The hose can be obtained from the same mold.

[0019]

According to the present invention, the vulcanized long hose body as described above is cut into a predetermined length according to the purpose of use, and the cut vulcanized hose body is provided with flexibility. After inserting the mandrel having it, heat treatment at a predetermined temperature for a predetermined time, and molding the vulcanized hose body assembly into which the mandrel in this heated state has been inserted in advance, considering the bending back angle after molding. After fitting the mold into the mold and cooling the assembly fitted in the mold at the specified temperature for a specified time in the cooling process, the assembly is removed from the mold and the mandrel is removed from the main body of the molding hose to obtain the specified shape. Since the product molding hose is manufactured, secondary vulcanization as in the past is not required, and therefore productivity can be improved, and molding can be performed without scratching the appearance of the molding hose, and further on the inner surface. Tree Even in the case of a hose body having a layer, it is possible to effectively prevent wrinkles from occurring in the resin layer at the bent portion, and even in the case of a normal rubber hose, do not flatten the bent portion and always use a highly accurate molded hose. Since it can be manufactured and it is not necessary to cut the end portion of the product molding hose, it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a flowchart showing manufacturing steps of a molded hose.

FIG. 2 is an explanatory view showing a manufacturing process of a molded hose.

FIG. 3 is a graph explanatory view showing a bending return angle of a product molding hose.

FIG. 4 is an explanatory diagram showing the configuration of a molded hose having a resin layer as the innermost layer.

FIG. 5 is an explanatory view showing the structure of a normal molded hose.

[Explanation of symbols]

 1 Vulcanized hose body 1a Assembly 2 Mandrel 3a, 3b Mold

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B32B 25/18 9155-4F F16L 11/04 7123-3J // B29K 21:00 B29L 9:00 4F 23:22 4F

Claims (4)

[Claims] 1. A vulcanized long hose is cut into a predetermined length according to the purpose of use, a flexible mandrel is inserted into the cut vulcanized hose body, and then a predetermined temperature is set. After heat-treating for a prescribed time, the assembly of the vulcanized hose body with the mandrel in this heated state is inserted into the molding die that was formed in advance with the bending back angle after molding preformed, and the molding die After cooling the assembly fitted in to the cooling step at a predetermined temperature for a predetermined time, the assembly is released from the mold, and the mandrel is removed from the molding hose body to manufacture a product molding hose with a predetermined shape. A method for producing a characteristic molded hose. 2. As the vulcanized long hose body,
The method for producing a molded hose according to claim 1, wherein a thermoplastic resin is used for the innermost layer and butyl rubber is used for the intermediate layer and the outermost layer. 3. As the vulcanized long hose body,
The method for producing a molded hose according to claim 1, wherein butyl rubber is used for the innermost layer and the outermost layer. 4. The method for producing a molding hose according to claim 1, wherein the molding die is set such that the bending return angle of the product molding hose after the molding is 30% or less.