JPH0671736A - Manufacture of rubber and resin composite hose - Google Patents

Abstract

PURPOSE:To provide manufacture of hoses without necessitating cutting off bag-like closed ends after blow molding, and besides, comprising a laminated structure of a rubber outer layer and a resin inner layer with a good dimensional accuracy in its end inner surfaces. CONSTITUTION:A rubber outer layer 12 is previously molded into a predetermined shape, and a thin walled thickness resin inner layer 14 is previously molded into a tube shape separately with the rubber outer layer 12, and then a previously molded resin tube 28 is set inside of the rubber layer 12 and core molds 48, 52 are inserted inside of opening end of the resin tube 28 so as to block the ends and regulate the inner diameter. Thereafter, or by heating prior to this, through a heating process separately with the previously molding process, the resin tube 28 is softened and blow molded, thus, forming the resin inner layer 14 being in close contact with the inner surface of the rubber outer layer 12.

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 hose, and more particularly to a hose for automobiles such as a filler hose which requires gasoline resistance and gasoline permeation resistance, and an air intake hose which requires oil resistance and heat resistance. The present invention relates to a manufacturing method suitable for manufacturing.

[0002]

2. Description of the Related Art In automobile filler hose (fuel hose) and the like, conventionally, rubber materials such as NBR / PVC rubber which are resistant to gasoline and permeation to gasoline have been used.

However, regulations on gasoline permeation have become stricter in recent years, and it has become difficult to cope with the conventional hose made of a rubber single layer.

In such a situation, it is considered that a thin fluororubber film (inner layer) 102 is formed inside the rubber outer layer 100 as shown in FIG. 5 (A). In the case of this type of hose, although the performance is good, there is a problem that the cost becomes high, and it is difficult to adopt in reality.

On the other hand, as shown in FIG. 5B, a hose in which a thin resin inner layer 106 is formed inside a thick rubber outer layer 104 is also considered.
The method shown in (A) has been proposed (JP-A-3-275).
238).

In this method, the rubber outer layer 104 is molded by molding or the like, and separately, the resin parison 108 whose end is closed like a bag is injection molded, and as shown in the figure. The parison 108 is removed from the injection mold and rotated by 90 ° while maintaining the molten state, and the rubber outer layer 104 that has been previously molded is set therein, and the resin parison 10 in that state is set.
8 is blown to the rubber outer layer 104.
The hose having the above-mentioned two-layer structure is produced by molding so as to be closely attached to the inner surface of the.

[0007]

However, in the case of this method, it is necessary to cut the bag-shaped closed portion after the resin parison 108 is blow-molded, which causes material loss correspondingly and the cutting step. Due to this, there is a problem that the number of manufacturing steps increases and the processing cost increases.

Further, since the inner surface of the end portion of the resin inner layer is molded in a free state, the dimensional accuracy of the inner surface of the same end portion is poor, and when the mating pipe to which the hose is connected is inserted inside the same end portion. However, there is a problem that it is difficult to obtain sufficient sealability.

Further, in the case of this method, there is a problem that a complicated device is required and the equipment cost becomes high, and it is difficult to make the resin inner layer 106 thinner than a certain thickness (for example, 0.2 mm or less). .

If the parison 108 is formed too thin,
This is because it becomes difficult to set the cooling rate inside the outer rubber layer 104 while maintaining the molten state and blow molding the cooling rate.

When the rubber outer layer 104 and the resin inner layer 106 are strongly adhered to each other in this method, an adhesive is applied to the inner surface of the rubber outer layer 104. In this way, the adhesive is applied to the inner surface of the rubber outer layer 104. In that case, there is a problem that it is difficult to control the film thickness of the adhesive and dry it after applying the adhesive.

[0012]

The present invention has been made to solve the above problems, and its gist is to manufacture a laminated structure hose having a thin resin inner layer on the inner surface of a rubber outer layer having a predetermined shape. In the method, the rubber outer layer is preformed into the predetermined shape, the thin resin inner layer is preformed into a tube shape separately from the rubber outer layer, and the preformed resin tube is provided inside the rubber outer layer. And the inner end of the resin tube is closed by inserting a core mold inside the opening end of the resin tube and regulating the inner diameter, and thereafter or prior to this, by heating in a heating step separate from the preforming step. The resin tube is softened and then blow-molded to form an inner resin layer that is in close contact with the inner surface of the outer rubber layer.

[0013]

According to the present invention, the resin tube is blow-molded with the core die inserted inside the opening end of the preformed resin tube and the end opening is closed. The end of the resin tube itself does not need to be closed in a bag shape during molding.

Therefore, unlike the conventional method, it is not necessary to cut off the end portion closed like a bag later, the material loss is reduced accordingly, the number of processing steps is reduced, and the processing cost is also low. Become.

Further, since the inner surface of the end of the resin tube is blow-molded by the core mold, the inner surface of the end of the hose can be molded with high dimensional accuracy, and the mating pipe is inserted inside the end to connect. The sealing property when performing is improved.

In addition, in the present invention, since the resin tube is prepared in advance in a separate step by preforming and the tube is softened again and then blow molded, the hose can be obtained by simply using an ordinary simple blow mold. Can be manufactured, and the die and equipment costs can be reduced.

As described above, according to the present invention, a resin tube to be subjected to blow molding is molded in advance, and thereafter, a core die is attached to the end of the resin tube to perform blow molding. Various kinds of hoses can be manufactured by changing the blow mold using the resin tube that has been prepared. That is, according to the present invention, when manufacturing hoses of various shapes, the steps up to obtaining the resin tube can be made common.

When the preformed resin tube is blow-molded, it is heated and softened in a heating step separate from the preforming, so that there is no problem even if the preformed resin tube is cooled thereafter. Compared with the manufacturing method shown in FIG. 6 (A), the resin tube can be formed thinner,
It is possible to form the resin inner layer thinly. For example, according to the present invention, if the gasoline permeation resistance is satisfied, it is possible to reduce the thickness of the resin inner layer to about 0.01 mm, which is advantageous in improving the flexibility and sealing property of the hose. .

In addition, in the present invention, since the resin tube is preformed in a step separate from the blow molding, there is an advantage that the outer surface of the resin tube can be subjected to an adhesive treatment prior to the blow molding. In this case, unlike the case where the adhesive treatment is applied to the inner surface of the rubber outer layer, the film thickness control of the adhesive and the drying treatment after the adhesive application are easy.

In the present invention, it is desirable to adopt an extrusion molding method as a molding method for the resin tube. According to such extrusion molding, a resin tube of a fixed length can be continuously produced in large quantities and at low cost by cutting the resin tube into a long length and then cutting it into predetermined dimensions. It is easy to reduce the thickness to about 0.01 mm, and in addition, the extruded long tube can be easily subjected to an adhesive treatment on its outer surface by immersing it in an adhesive solution.

[0021]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an example of a hose such as a filler hose and an air intake hose. The hose 10 in FIG. 2A has a thick rubber wall (for example, a wall thickness of 2 mm or more) and a flexible rubber outer layer 12, and a thin wall (for example, (Wall thickness 0.5 mm or less)
Of the resin inner layer 14 and a bellows portion 16 is formed in the middle portion in the longitudinal direction.

Here, the thin resin inner layer 14 is made of a hard resin material having excellent resistance to internal fluid (gasoline resistance, gasoline permeation resistance, etc.).

The hose 18 of (B) has a rubber outer layer 12 which is also thick and a resin inner layer 14 which is thin and resistant to internal fluids.
And has a curved shape that is curved at a substantially middle curved portion 20 in the longitudinal direction. Then, a bellows portion 16 is formed on one side of the bent portion 20 in the same manner as the hose 10.

The hose 22 of (C) is the hose 10,
Similarly to 18, a thick rubber outer layer 12 and a thin resin inner layer 14 having a good inner fluid resistance are laminated. However, this hose 22 does not have a bellows-shaped portion, but has two bent portions 24 and 26 that are curved.

FIG. 1 shows an example of a method for manufacturing the hose 10. As shown in the figure, in the method of this example, the bellows portion 1
The thick rubber outer layer 12 having 6a and the straight resin tube 28 are separately preformed. Rubber outer layer 1
As the molding method of No. 2, a molding method such as injection molding and other molding methods can be adopted.

Various molding methods can be used for molding the resin tube 28, but extrusion molding is the most preferable method. Specifically, as shown in FIG. 3, a resin tube 28a is continuously extruded in a long shape from an extruder 30, and at that time, the tube 28a is dimensioned from the inner surface side by a sizing die 38 and the cooling is continued. The tube 28a extruded in the step 32, the drying step 34, and the adhering step 36 is cooled, dried, and adhered, and then cut into predetermined dimensions.
A resin tube 28 having a constant length is obtained.

Here, as the bonding process in the bonding step 36, a method of immersing the resin tube 28a in a bonding tank 40 containing a bonding liquid 42 as shown in FIG. As described above, the tube 28a is continuously brought into contact with the sponge 44 impregnated with the adhesive 42 to perform an adhesion treatment, or the method of spraying the adhesive 42 from the nozzle 46 as shown in FIG. Any method can be used.

In the method of this example, as shown in FIG. 7B, the resin tube 28 prepared as described above is inserted into the rubber outer layer 12 prepared separately and inside the end portion of the resin tube 28. The core die 48 and the core die 52 having the blow hole 50 are respectively inserted in a close contact state to close the end opening and the inner diameters of the end portions are regulated by these core dies 48, 52.

Then, as shown in (C), these are set in the cavity of the blow mold 54. At this time, the resin tube 28 is preheated to a substantially molten state and then set in the blow mold 54. Alternatively, after being set in the blow mold 54, the resin tube 28 is heated to be in a substantially molten state.

As the former heating method, the resin tube 2 is used.
8, the rubber outer layer 12, and the core molds 48, 52 as a whole may be placed in a heating oven to heat them, or heating with hot air or other methods may be used, and the latter heating method is shown in FIG. As described above, it is possible to use a method in which the heater 56 (for example, a far infrared heater) extended so as to penetrate the core die 48 is positioned inside the resin tube 28 and the resin tube 28a is heated by the heater 56. it can. Of course, it is possible to use other heating methods.

Now, when the resin tube 28 is brought into a substantially molten state by heating, the core mold 52 is then formed as shown in (D).
Air is blown from the blow hole 50 of the resin tube 28
Is inflated to form a thin resin inner layer 14 that is in close contact with the inner surface of the rubber outer layer 12, and at the same time, this is adhered to the inner surface of the rubber outer layer 12.

When the heated resin tube 28 is blow-molded, air may be trapped between the resin tube 28 and the rubber outer layer 12 to prevent good adhesion therebetween. This can be solved by forming a large number of fine holes in the rubber outer layer 12 and letting air escape to the outside through the holes.

Alternatively, this can be solved by a separate method shown in FIG. For example, as shown in (A), a stopper 58 is attached to the end portion of the rubber outer layer 12, and the stopper 5
It is possible to prevent air from being trapped by inserting the resin tube 28 together with the core die 48 while vacuum suctioning the air inside the rubber outer layer 12 through the suction hole 60 provided in the No. 8.

Alternatively, as shown in (B), a core type having a core type having an elastic film 62 capable of expanding / contracting a diameter and a fluid supply passage 64 for expanding and expanding the elastic film 62. By using 66, and by blowing the air into the resin tube 28 and swelling and expanding the diameter of the elastic film 62 at different timings, the air between the resin tube 28 and the rubber outer layer 12 is discharged to the outside. You can also escape to. At this time, it is effective to perform vacuum suction of air through the ends of the resin tube 28 and the rubber outer layer 12 together.

As described above, in this method, since the resin tube 28 is blow-molded with both ends thereof closed by the core molds 48 and 52, it is necessary to keep the ends of the resin tube 28 itself in a bag shape. Absent. Therefore, there is no need for a step of cutting off the bag-shaped closed portion thereafter. Therefore, there is no material loss due to the cutting, and the product can be obtained as it is by blow molding, which simplifies the processing steps.

Further, the resin tube 28 is attached to the core dies 48 and 52.
Since blow molding is performed with the inner diameter of the end of the tube being regulated, a blow molded product (hose 10) with good dimensional accuracy of the inner surface of the end
Is obtained.

Further, as is apparent from the above description, the method of this example has the advantage that the ordinary simple blow mold is sufficient, and the mold cost and equipment cost are low.

Further, in the method of this embodiment, since the resin tube 28 is extruded, it is possible to form the resin tube 28 to be thin (0.01 if necessary).
resin tube 2
It can be applied to the outer peripheral surface of No. 8 and has an advantage that the film thickness control of the adhesive and the drying process of the adhesive are easy.

However, the adhesion treatment may be performed on the inner surface of the rubber outer layer 12 in some cases, and the rubber outer layer 1 may be further applied.
It is also possible to incorporate an adhesive into the 2 and / or resin tube 28 by kneading.

By applying such an adhesive treatment, it is possible to prevent the resin inner layer 14 from falling down from the rubber outer layer 12 like a shelf due to vibration, negative pressure or the like applied to the hose, as shown in FIG. 6B. Can be prevented.

However, when the resin inner layer 14 is relatively thick (for example, 0.5 mm or more), there is less possibility that the resin inner layer 14 will fall like a shelf from the rubber outer layer 12 even if vibration or negative pressure acts on the hose. In some cases, the bonding process can be omitted.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be carried out in a mode in which various modifications are made based on 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 diagram of an embodiment method of the present invention.

FIG. 2 is a diagram showing an example of a hose obtained by the method of the present invention.

FIG. 3 is an explanatory view of an example of a molding method of the resin tube in FIG. 1 and a bonding method.

FIG. 4 is an explanatory diagram of another embodiment method of the present invention.

FIG. 5 is a background explanatory view of the present invention.

FIG. 6A is a background illustration of the present invention. (B) is a comparative example diagram for explaining the advantages of the embodiment shown in FIG. 1.

[Explanation of symbols]

 10, 18 and 22 Hose 12 Rubber outer layer 14 Resin inner layer 28 Resin tube 48, 52, 66 Core type 30 Extruder 50 Blow hole 54 Blow type 56 Heater

[Procedure amendment]

[Submission date] August 31, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

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 hose, and more particularly to a hose for automobiles such as a filler hose which requires gasoline resistance and gasoline permeation resistance, and an air intake hose which requires oil resistance and heat resistance. The present invention relates to a manufacturing method suitable for manufacturing.

[0002]

2. Description of the Related Art In automobile filler hose (fuel hose) and the like, conventionally, rubber materials such as NBR / PVC rubber which are resistant to gasoline and permeation to gasoline have been used.

However, regulations on gasoline permeation have become stricter in recent years, and it has become difficult to cope with the conventional hose made of a rubber single layer.

In such a situation, it is considered that a thin fluororubber film (inner layer) 102 is formed inside the rubber outer layer 100 as shown in FIG. 5 (A). In the case of this type of hose, although the performance is good, there is a problem that the cost becomes high, and it is difficult to adopt in reality.

On the other hand, as shown in FIG. 5B, a hose in which a thin resin inner layer 106 is formed inside a thick rubber outer layer 104 is also considered.
The method shown in (A) has been proposed (JP-A-3-275).
238).

In this method, the rubber outer layer 104 is molded by molding or the like, and separately, the resin parison 108 whose end is closed like a bag is injection molded, and as shown in the figure. The parison 108 is removed from the injection mold and rotated by 90 ° while maintaining the molten state, and the rubber outer layer 104 that has been previously molded is set therein, and the resin parison 10 in that state is set.
8 is blown to the rubber outer layer 104.
The hose having the above-mentioned two-layer structure is produced by molding so as to be closely attached to the inner surface of the.

[0007]

However, in the case of this method, it is necessary to cut the bag-shaped closed portion after the resin parison 108 is blow-molded, which causes material loss correspondingly and the cutting step. Due to this, there is a problem that the number of manufacturing steps increases and the processing cost increases.

Further, since the inner surface of the end portion of the resin inner layer is molded in a free state, the dimensional accuracy of the inner surface of the same end portion is poor, and when the mating pipe to which the hose is connected is inserted inside the same end portion. However, there is a problem that it is difficult to obtain sufficient sealability.

Further, in the case of this method, there is a problem that a complicated device is required and the equipment cost becomes high, and it is difficult to make the resin inner layer 106 thinner than a certain thickness (for example, 0.2 mm or less). .

If the parison 108 is formed too thin,
This is because it becomes difficult to set the cooling rate inside the outer rubber layer 104 while maintaining the molten state and blow molding the cooling rate.

When the rubber outer layer 104 and the resin inner layer 106 are strongly adhered to each other in this method, an adhesive is applied to the inner surface of the rubber outer layer 104. In this way, the adhesive is applied to the inner surface of the rubber outer layer 104. In that case, there is a problem that it is difficult to control the film thickness of the adhesive and dry it after applying the adhesive.

[0012]

The present invention has been made to solve the above problems, and its gist is to manufacture a laminated structure hose having a thin resin inner layer on the inner surface of a rubber outer layer having a predetermined shape. In the method, the rubber outer layer is preformed into the predetermined shape, the thin resin inner layer is preformed into a tube shape separately from the rubber outer layer, and the preformed resin tube is provided inside the rubber outer layer. And the inner end of the resin tube is closed by inserting a core mold inside the opening end of the resin tube and regulating the inner diameter, and thereafter or prior to this, by heating in a heating step separate from the preforming step. The resin tube is softened and then blow-molded to form an inner resin layer that is in close contact with the inner surface of the outer rubber layer.

[0013]

According to the present invention, the resin tube is blow-molded with the core die inserted inside the opening end of the preformed resin tube and the end opening is closed. The end of the resin tube itself does not need to be closed in a bag shape during molding.

Therefore, unlike the conventional method, it is not necessary to cut off the end portion closed like a bag later, the material loss is reduced accordingly, the number of processing steps is reduced, and the processing cost is also low. Become.

Further, since the inner surface of the end of the resin tube is blow-molded by the core mold, the inner surface of the end of the hose can be molded with high dimensional accuracy, and the mating pipe is inserted inside the end to connect. The sealing property when performing is improved.

In addition, in the present invention, since the resin tube is prepared in advance in a separate step by preforming and the tube is softened again and then blow molded, the hose can be obtained by simply using an ordinary simple blow mold. Can be manufactured, and the die and equipment costs can be reduced.

As described above, according to the present invention, a resin tube to be subjected to blow molding is molded in advance, and thereafter, a core die is attached to the end of the resin tube to perform blow molding. Various kinds of hoses can be manufactured by changing the blow mold using the resin tube that has been prepared. That is, according to the present invention, when manufacturing hoses of various shapes, the steps up to obtaining the resin tube can be made common.

When the preformed resin tube is blow-molded, it is heated and softened in a heating step separate from the preforming, so that there is no problem even if the preformed resin tube is cooled thereafter. Compared with the manufacturing method shown in FIG. 6 (A), the resin tube can be formed thinner,
It is possible to form the resin inner layer thinly. For example, according to the present invention, if the gasoline permeation resistance is satisfied, it is possible to reduce the thickness of the resin inner layer to about 0.01 mm, which is advantageous in improving the flexibility and sealing property of the hose. .

In addition, in the present invention, since the resin tube is preformed in a step separate from the blow molding, there is an advantage that the outer surface of the resin tube can be subjected to an adhesive treatment prior to the blow molding. In this case, unlike the case where the adhesive treatment is applied to the inner surface of the rubber outer layer, the film thickness control of the adhesive and the drying treatment after the adhesive application are easy.

In the present invention, the resin inner layer is separated from the rubber outer layer.
Although it is preformed into a tubular shape,
Pre-molding of the rubber outer layer, pre-molding of the resin inner layer and
When performing low molding on completely separate production lines, the rubber outer layer
Separate production line for preforming and resin inner layer preforming
After that, combine those production lines and the subsequent process
Or in one continuous production line
Rubber outer layer preforming, resin inner layer preforming, blow molding
When performing, both are included.

In the present invention, it is desirable to adopt an extrusion molding method as the molding method of the resin tube. According to such extrusion molding, a resin tube of a fixed length can be continuously produced in large quantities and at low cost by cutting the resin tube into a long length and then cutting it into predetermined dimensions. It is easy to reduce the thickness to about 0.01 mm, and in addition, the extruded long tube can be easily subjected to an adhesive treatment on its outer surface by immersing it in an adhesive solution.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an example of a hose such as a filler hose or an air intake hose. The hose 10 in FIG. 2A has a thick wall (for example, a wall thickness of 2 mm or more . The length is, for example, 3 mm) .
00 mm ) and a flexible rubber outer layer 12, and a thin wall (for example, a wall thickness of 0.5 mm or less . An average wall thickness of 0.2).
mm. It has a laminated structure with the resin inner layer 14 having a diameter of 34 mmφ ), and a bellows portion 16 is formed at the middle portion in the longitudinal direction.

The thin resin inner layer 14 is made of a hard resin material having excellent resistance to internal fluid (gasoline resistance, gasoline permeation resistance, etc.).

The hose 18 of (B) has a rubber outer layer 12 which is also thick and a resin inner layer 14 which is thin and resistant to internal fluids.
And has a curved shape that is curved at a substantially middle curved portion 20 in the longitudinal direction. Then, a bellows portion 16 is formed on one side of the bent portion 20 in the same manner as the hose 10.

The hose 22 of (C) is the hose 10,
Similarly to 18, a thick rubber outer layer 12 and a thin resin inner layer 14 having a good inner fluid resistance are laminated. However, this hose 22 does not have a bellows-shaped portion, but has two bent portions 24 and 26 that are curved.

FIG. 1 shows an example of a method for manufacturing the hose 10. As shown in the figure, in the method of this example, the bellows portion 1
The thick rubber outer layer 12 having 6a and the straight resin tube 28 are separately preformed. Rubber outer layer 1
As the molding method of No. 2, a molding method such as injection molding and other molding methods can be adopted.

Various molding methods can be used for molding the resin tube 28, but extrusion molding is the most preferable method. Specifically, as shown in FIG. 3, a resin tube 28a is continuously extruded in a long shape from an extruder 30, and at that time, the tube 28a is dimensioned from the inner surface side by a sizing die 38 and the cooling is continued. The tube 28a extruded in the step 32, the drying step 34, and the adhering step 36 is cooled, dried, and adhered, and then cut into predetermined dimensions.
A resin tube 28 having a constant length is obtained.

Here, as the bonding process in the bonding step 36, as shown in FIG. 3A, the resin tube 28a is immersed in the bonding tank 40 containing the bonding liquid 42, or as shown in FIG. As described above, the tube 28a is continuously brought into contact with the sponge 44 impregnated with the adhesive 42 to perform an adhesion treatment, or the method of spraying the adhesive 42 from the nozzle 46 as shown in FIG. Any method can be used.

Other methods include Na treatment and flame treatment.
Examples of such processes include processing, corona treatment, and sputtering treatment.
Here, the Na treatment is performed as follows, for example. That is, first
Toluene degreasing followed by sodium etching
Liquid (sodium-naphthalene in tetrahydrofuran or
Immersion in an ammonia solvent) (15 seconds to 1)
For about a minute), and then wash with methanol to remove excess
Remove the sodium etching solution, and then wash with water.
Purification is performed to remove the attached methanol. These
A blind stopper is provided to prevent various treatment liquids from entering the inner surface during treatment.
deep.

On the other hand, the corona treatment is preformed at atmospheric pressure.
Corona discharge is applied to the tube. See you
The tailing process is an algorithm that is excited in a magnetic or electric field.
Gas by colliding with the preformed tube.
Gon etching is performed.

In the method of this example, the resin tube 28 prepared as described above is inserted into the rubber outer layer 12 separately prepared as shown in FIG. The core die 48 and the core die 52 having the blow hole 50 are respectively inserted in a close contact state to close the end opening and the inner diameters of the end portions are regulated by these core dies 48, 52.

Then, as shown in (C), these are set in the cavity of the blow mold 54. At this time, the resin tube 28 is preheated to a substantially molten state and then set in the blow mold 54. Alternatively, after being set in the blow mold 54, the resin tube 28 is heated to be in a substantially molten state.

As the former heating method, the resin tube 2 is used.
8, the rubber outer layer 12, and the core molds 48, 52 as a whole may be placed in a heating oven to heat them, or heating with hot air or other methods may be used, and the latter heating method is shown in FIG. As described above, it is possible to use a method in which the heater 56 (for example, a far infrared heater) extended so as to penetrate the core die 48 is positioned inside the resin tube 28 and the resin tube 28a is heated by the heater 56. it can. Of course, it is possible to use other heating methods.

Now, when the resin tube 28 is brought into a substantially molten state by heating, the core mold 52 is then formed as shown in (D).
Air is blown from the blow hole 50 of the resin tube 28
Is inflated to form a thin resin inner layer 14 that is in close contact with the inner surface of the rubber outer layer 12, and at the same time, this is adhered to the inner surface of the rubber outer layer 12.

When the heated resin tube 28 is blow-molded, air may be trapped between the resin tube 28 and the rubber outer layer 12 to prevent good adhesion therebetween. This can be solved by forming a large number of fine holes in the rubber outer layer 12 and letting air escape to the outside through the holes.

Alternatively, this can be solved by a separate method shown in FIG. For example, as shown in (A), a stopper 58 is attached to the end portion of the rubber outer layer 12, and the stopper 5
It is possible to prevent air from being trapped by inserting the resin tube 28 together with the core die 48 while vacuum suctioning the air inside the rubber outer layer 12 through the suction hole 60 provided in the No. 8.

Alternatively, as shown in (B), a core type having an elastic film 62 capable of expanding / contracting a diameter as a core type and a fluid supply passage 64 for expanding and expanding the elastic film 62. By using 66, and by blowing the air into the resin tube 28 and swelling and expanding the diameter of the elastic film 62 at different timings, the air between the resin tube 28 and the rubber outer layer 12 is discharged to the outside. You can also escape to. At this time, it is effective to perform vacuum suction of air through the ends of the resin tube 28 and the rubber outer layer 12 together.

As described above, in this method, blow molding is performed with both ends of the resin tube 28 closed by the core molds 48 and 52, so that the ends of the resin tube 28 itself need to be closed in a bag shape. Absent. Therefore, there is no need for a step of cutting off the bag-shaped closed portion thereafter. Therefore, there is no material loss due to the cutting, and the product can be obtained as it is by blow molding, which simplifies the processing steps.

Further, the resin tube 28 is attached to the core dies 48 and 52.
Since blow molding is performed with the inner diameter of the end of the tube being regulated, a blow molded product (hose 10) with good dimensional accuracy of the inner surface of the end
Is obtained.

Further, as is apparent from the above description, the method of this embodiment has the advantage that the ordinary simple blow mold is sufficient, and the mold cost and equipment cost are low.

In addition, since the resin tube 28 is extruded in the method of this embodiment, it is possible to form the resin tube 28 thinly (0.01 if necessary).
resin tube 2
It can be applied to the outer peripheral surface of No. 8 and has an advantage that the film thickness control of the adhesive and the drying process of the adhesive are easy.

However, in some cases, the adhesive treatment may be applied to the inner surface of the rubber outer layer 12, and further, the rubber outer layer 1
It is also possible to incorporate an adhesive into the 2 and / or resin tube 28 by kneading.

By applying such an adhesive treatment, it is possible to prevent the resin inner layer 14 from falling down from the rubber outer layer 12 like a shelf due to vibration, negative pressure or the like applied to the hose, as shown in FIG. 6B. Can be prevented.

However, when the resin inner layer 14 is relatively thick (for example, 0.5 mm or more), it is less likely that the resin inner layer 14 will fall like a shelf from the rubber outer layer 12 even if vibration or negative pressure acts on the hose. In some cases, the bonding process can be omitted.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be carried out in a mode in which various modifications are made based on the knowledge of those skilled in the art without departing from the spirit of the invention. .

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display area B29L 9:00 4F 23:22 4F

Claims (2)

[Claims] 1. A method of manufacturing a laminated structure hose having a thin resin inner layer on the inner surface of a rubber outer layer having a predetermined shape, wherein the rubber outer layer is preformed into the predetermined shape, and
The thin resin inner layer is preformed into a tube shape separately from the rubber outer layer, the preformed resin tube is set inside the rubber outer layer, and a core mold is inserted inside the open end of the resin tube. The end portion is closed and the inner diameter is regulated, and thereafter or prior to this, the resin tube is softened by heating in a heating step separate from the preforming step, and then blow molded to form the rubber outer layer. A method for producing a rubber / resin composite hose, which comprises forming a resin inner layer that adheres to the inner surface. 2. The method for producing a rubber / resin composite hose according to claim 1, wherein the resin tube is preformed by extrusion molding.