JP2004069022A - Resin pipe, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin pipe that can be directly connected to a hose, and that has excellent seal performance, and a method for manufacturing that. <P>SOLUTION: The resin pipe 20 is provided with a pipe body 22 formed of first resin material (PPS), and a reinforcement layer 24 laminated as tightly applied to an inner circumferential part of a connection end 20b, and formed of second resin material. The second resin material is provided with improved bending modulus of elasticity by setting it to contain 30 wt.% glass fibers in PPS. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a resin pipe having a connection end for fastening a hose and a method for manufacturing the same.
[0002]
[Prior art and its problems]
Conventionally, as shown in FIG. 7, a resin pipe for connecting a hose is known. FIG. 7 is a sectional view showing a portion where a hose is connected to a resin pipe. The resin pipe 100 is used, for example, for a water system piping of an automobile, and is connected to a hose 102 via a joint 104. That is, one end of the joint 104 is pressed into the connection end 100a of the resin pipe 100 provided with the annular reinforcing layer 106. Then, the hose 102 is attached to the outer periphery of the other end of the joint 104 and the hose 102 is fixed by the clip 108. The joint 104 is manufactured by injection molding a resin material having higher mechanical strength than the resin pipe, for example, a resin material mixed with glass fiber or the like so as to have a pressure resistance up to about 120 ° C.
[0003]
In the above-described conventional technique, since the joint 104 is separately manufactured by injection molding, there is a problem that the number of parts increases and the cost increases. In order to solve such a problem, a method of increasing the thickness of the connection end 100a of the resin pipe 100 and using an extrusion blow molding method without using the joint 104 has been studied. However, there is a problem that it is difficult to partially increase the thickness of the connection end 100a that can cope with the thermal stress of 120 ° C. by extrusion blow molding or the like.
[0004]
As another technique, Japanese Patent Publication No. 7-67731 is known. That is, a method of sequentially extruding a plurality of resin materials by extrusion blow molding, that is, a method of extruding by switching between a soft resin material forming a pipe body and a hard resin material forming a connection end. However, the resin pipe manufactured by this method is difficult to connect with liquid tightness because the pipe body and the connection end are made of different resin materials, and liquid penetrates from the connection interface to seal. It may not be applicable to resin pipes for transporting liquid because of the possibility of deterioration or breakage.
[0005]
An object of the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a resin pipe which can be directly connected to a hose and has excellent sealing properties, and a method of manufacturing the same.
[0006]
[Means for Solving the Problems and Their Functions and Effects]
The present invention has been made to solve the above problems,
In a resin pipe connected to a hose, a glass body formed of a first resin material and having a connection end for connecting the hose and a glass fiber laminated and integrated in close contact with an inner peripheral portion of the connection end And a reinforcing layer formed of a second resin material having a higher mechanical strength than the first resin material.
[0007]
To connect the hose to the resin pipe according to the present invention, the connection end of the end of the resin pipe is press-fitted into the hose. Since the connection end is enhanced in mechanical strength by a reinforcing layer laminated and integrated in close contact with the inner peripheral portion of the pipe body, the connection end is deformed even when pressed into a hose and used in a high temperature environment. Without this, excellent sealing properties with respect to the hose can be obtained.
[0008]
Since the reinforcing layer constitutes a connection end by being laminated in close contact with the inner peripheral portion of the pipe main body, it is possible to reduce the number of parts and reduce costs without becoming a separate member from the pipe main body. be able to.
[0009]
Further, since the reinforcing layer is formed of the second resin material having a higher mechanical strength than the first resin material forming the pipe main body, even when used in a high temperature environment, deformation of the hose with respect to the fastening force of the hose is prevented. Since the resistance is large, the sealing performance is not reduced.
[0010]
The first resin material can be determined in consideration of characteristics suitable for the pipe body, for example, a material for a cooling water system in an automobile engine, that is, a material and a bending characteristic in consideration of resistance to antifreeze liquid containing ethylene glycol as a main component. For example, the first resin material can be formed from polyphenylene sulfide or an aromatic polysulfide resin (hereinafter abbreviated as PPS resin) which is a modified product thereof, a polyamide resin, or a mixture thereof.
[0011]
As a preferred embodiment of the second resin material, it is preferable to prepare a resin material having a flexural modulus at 120 ° C. of 1000 MPa or more, particularly preferably 1700 MPa or more. It can be formed from a material to which 5 to 30% by weight of glass fiber is added. Here, if the glass fiber content exceeds 30% by weight, the adhesion to the pipe main body and the extrusion moldability are impaired, so that the content is preferably less than this.
[0012]
In addition, it is preferable to use the same resin material as the first resin material for the second resin material because the two are thermally welded to increase the bonding strength. When a resin material different from the first resin material is used as the second resin material, it is preferable to increase the adhesive strength by interposing an adhesive layer therebetween.
[0013]
Further, as another preferred embodiment, it is possible to adopt a configuration in which all ends of the interface where the reinforcing layer and the pipe main body are in contact with each other are exposed in the flow path in the pipe main body or the hose. . With this configuration, since the reinforcing layer is laminated on the inner peripheral side of the pipe main body, that is, even if the liquid permeates the interface between the pipe main body, it returns to the flow path in the pipe main body and leaks to the outside. Since it does not occur, it has excellent sealing properties.
[0014]
According to another aspect of the present invention, there is provided a method of manufacturing a resin pipe, wherein the pipe body is formed by extruding the first resin material into a cavity of a mold having a molding surface following an outer peripheral surface of the pipe body. And extruding the second resin material toward the inner peripheral side of the pipe main body at the timing of forming the connection end, and blowing air into the pipe main body and / or evacuating the molding surface. By doing so, a method including a step of forming the reinforcing layer at the connection end can be adopted. According to this method, a resin pipe having a reinforcing layer can be continuously and easily manufactured.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be described below to further clarify the configuration and operation of the present invention described above.
[0016]
(1) Schematic Configuration of Piping Structure FIG. 1 is an explanatory diagram showing a piping system using a resin pipe according to one embodiment of the present invention. The piping system is used for water system piping of an automobile. A connection end 20b is formed at one end of the resin pipe 20, and an end of the hose 30 is press-fitted into the connection end 20b. The hose 30 is connected to the resin pipe 20 by being fastened by the clip 40.
[0017]
(2) Configuration of the Resin Pipe 20 The resin pipe 20 includes a flexible pipe body 22 having a cylindrical general portion 22A and a bellows portion 22B continuously formed, and a hose 30 is connected to one end thereof. Connection end 20b described above. On the outer peripheral portion of the connection end 20b, a retaining protrusion 20c for retaining the hose 30 is provided in an annular shape, and an annular protrusion 23a for retaining the end of the hose 30 is formed.
[0018]
(2) -1 Configuration of Pipe Body 22 FIG. 2 is a cross-sectional view showing a connection portion of a piping system. The pipe main body 22 includes the above-described general portion 22A and the bellows portion 22B, and includes the outer layer portion 22a that forms the connection end 20b together with the reinforcing layer 24.
[0019]
The resin material (first resin material) of the pipe main body 22 can be formed from polyphenylene sulfide or an aromatic polysulfide resin (hereinafter abbreviated as PPS resin) which is a modified product thereof, a polyamide resin, or a mixture thereof. The shape of the pipe main body 22 can be configured such that the outer diameter is 8 to 45 mm and the thickness of the outer layer portion 22a is 1 to 3 mm.
[0020]
(2) -2 Reinforcing layer 24
A reinforcing layer 24 is formed on the inner periphery of the connection end 20b. The reinforcing layer 24 is welded in close contact with the outer layer portion 22a, and the adhesive interface 25 in contact with the pipe main body 22 is disposed so as to be exposed to the pipe flow paths 20a, 30a in the pipe main body 22 or the hose 30. I have. The thickness of the reinforcing layer 24 is 0.5 to 2.5 mm under the above-described conditions.
[0021]
The reinforcing layer 24 is formed of a resin material (second resin material) having a mechanical strength higher than that of the first resin material by containing glass fibers in the first resin material. For example, when PPS is used as the first resin material, the flexural modulus at 100 ° C. is 930 MPa, whereas the second resin material obtained by adding 30% by weight of glass fiber to PPS has a flexural modulus at 100 ° C. The rate can be adjusted to 4900 MPa.
[0022]
The reinforcing layer 24 is preferably formed by using the same PPS as the pipe body 22, since the two are thermally welded and the bonding strength is increased without an intervening adhesive layer during blow extrusion molding described later.
[0023]
(3) Manufacturing Process of Resin Pipe 20 Next, a method of manufacturing the resin pipe 20 will be described. The resin pipe 20 is manufactured using a pipe manufacturing apparatus 50 shown in FIG.
[0024]
(3) -1 Pipe manufacturing device 50
FIG. 3 is a schematic configuration diagram illustrating a pipe manufacturing apparatus. The pipe manufacturing apparatus 50 includes a pipe extruder 60 that extrudes the extruded pipe 20P, a molding die unit 70 that shapes an outer peripheral portion of the extruded pipe 20P extruded from the pipe extruder 60, and a molding die unit. And a transport device 80 for transporting in a loop.
[0025]
FIG. 4 is a sectional view showing a pipe extruder and a part of a mold. The pipe extruder 60 supplies or shuts off a first cylinder 61 for extruding the first resin material, a second cylinder 62 for extruding the second resin material, and a resin material extruded from the first and second cylinders 61, 62, respectively. And a second shut-off valve 63 and a second shut-off valve 64 for feeding the resin material extruded from the first and second cylinders 61 and 62 into a partially extruded tubular body 20P. A die 65 having a first passage 65a and a second passage 65b, a blower 67 for blowing air to the extrusion pipe body 20P through a blow passage 65c in the die 65, and a control device 68 for controlling the first and second shut-off valves 63 and 64. And
[0026]
The molding die unit 70 includes a plurality of dies 71 and 72 each having a molding surface following each part such as the connection end 20b of the resin pipe 20, the general part 22A or the bellows part 22B, and these are formed by an extruded tube body. They are arranged so as to pass through a transport path FL for transporting 20P. The dies 71 and 72 are formed of split dies that are divided along the central axis of the extruded tubular body 20P to be conveyed, and each of the split dies has a loop shape and is clamped by the central axis. Are arranged as follows. A suction passage connected to a suction pump (not shown) as a shaping means is opened on the molding surfaces of the dies 71 and 72.
[0027]
(3) -2 Manufacturing Process of Resin Pipe 20 Next, a manufacturing process of the resin pipe 20 by the pipe manufacturing apparatus 50 will be described. Now, when the extruded tube 20P is extruded from the pipe extruder 60 while being blown through the passage 65c by the blower 67, the conveying device 80 (FIG. 3) clamps the molds 71 and 72 while conveying the molds 71 and 72. The resin pipe 20 is formed by shaping the extruded tube 20P.
[0028]
That is, the first shut-off valve 63 is opened under the control of the control device 68 to supply the first resin material from the first cylinder 61 through the first passage 65a, and to form the second shut-off valve at the timing of forming the connection end 20b. The off valve 64 is temporarily opened, the second resin material is supplied from the second cylinder 62 through the second passage 65b, and the second shutoff valve 64 is closed at a timing when the connection end 20b is not formed. As a result, the end of the extruded tube 20P to be the connection end 20b is formed in two layers, and the other portions are formed in one layer. Here, the thickness of each layer of the resin pipe 20 can be adjusted by changing the extrusion speed and the take-up speed.
[0029]
Then, the dies 71 and 72 are conveyed so as to be aligned with the die 65 of the pipe extruder 60, and the extruded tube 20P extruded from the die 65 is placed in the cavities 71a and 72a and clamped. As described above, the molds 71 and 72 sequentially approach the die 65, move in a direction orthogonal to the transport path FL, and clamp the extrusion tube body 20P. In a state where the molds 71 and 72 are clamped, the external shape of the extruded tube 20P is shaped by being blown into the extruded tube 20P and sucked by the suction device. Thereby, the resin pipe 20 having the reinforcing layer 24 is continuously manufactured.
[0030]
(3) Function / Effect of Resin Pipe 20 According to the resin pipe 20, the following function and effect are obtained in addition to the above-described function and effect.
[0031]
(3) -1 As shown in FIG. 2, the mechanical strength (flexural modulus) of the connection end 20 b is increased by the reinforcing layer 24 which is laminated in a state of being in close contact with the inner peripheral portion of the pipe body 22. Even if the hose 30 is press-fitted into the hose 30 and used in an environment with a high temperature, excellent sealing performance with respect to the hose 30 can be obtained without deformation.
[0032]
(3) -2 Since the reinforcing layer 24 forms the connection end 20b by being laminated in close contact with the inner peripheral portion of the pipe main body 22, it does not become a separate member from the pipe main body 22, and the number of parts is reduced. And cost can be reduced.
[0033]
(3) -3 As shown in FIG. 5, the reinforcing layer 24 is laminated on the inner peripheral side of the pipe main body 22, that is, even if the liquid permeates the bonding interface 25 between the pipe main body 22 and the liquid. Since it does not return to the pipe flow path 20a in the pipe main body 22 and leaks to the outside, the sealing performance is excellent. That is, as shown in FIGS. 6A and 6B, when a connection end CE formed of a resin material different from the pipe main body PM is formed at the connection end of the resin pipe RP, the liquid is formed at the bonding interface CEa. However, according to the above embodiment, such a problem does not occur.
[0034]
The present invention is not limited to the above embodiment, but can be implemented in various modes without departing from the scope of the invention.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a piping system using a resin pipe according to one embodiment of the present invention.
FIG. 2 is a sectional view showing a connection part of a piping system.
FIG. 3 is a schematic configuration diagram illustrating a pipe manufacturing apparatus.
FIG. 4 is a sectional view showing a pipe extruder and a part of a mold.
FIG. 5 is an explanatory diagram illustrating the operation of the present embodiment.
FIG. 6 is an explanatory diagram illustrating a problem of a comparative example.
FIG. 7 is a sectional view showing a portion where a hose is connected to a conventional resin pipe.
[Explanation of symbols]
20. . . Resin pipe 20P. . . Extruded tube 20a. . . Pipe channel 20b. . . Connection end 20c. . . Retaining projection 22. . . Pipe body 22A. . . General part 22B. . . Bellows 22a. . . Outer layers 23a. . . Annular projection 24. . . Reinforcing layer 25. . . Adhesive interface 30. . . Hose 40. . . Clip 50. . . Pipe manufacturing device 60. . . Pipe extruder 61. . . First cylinder 62. . . Second cylinder 63. . . First shut-off valve 64. . . Second shut-off valve 65. . . Dies 65a. . . The first passage 65b. . . Second passage 65c. . . Blow passage 67. . . Blower 68. . . Control device 70. . . Mold unit 71, 72. . . The molds 71a, 72a. . . Cavity 80. . . Transfer device

Claims (5)

In the resin pipe connected to the hose,
A pipe body formed of a first resin material and having a connection end for connecting the hose;
A reinforcing layer formed from a second resin material having a higher mechanical strength than the first resin material by being laminated and integrated in a state of being in close contact with the inner peripheral portion of the connection end and containing glass fibers;
A resin pipe comprising: In the resin pipe of claim 1,
The first resin material is formed from an aromatic polysulfide resin (hereinafter abbreviated as PPS resin) or a polyamide resin, which is a polyphenylene sulfide or a modified product thereof, or a mixture thereof,
The second resin material is formed from a material obtained by adding 5 to 30% by weight of glass fiber to the first resin material;
A resin pipe. In the resin pipe according to claim 1 or 2,
A resin pipe in which the second resin material is adjusted to have a flexural modulus at 120 ° C. of 1000 MPa or more. The resin pipe according to any one of claims 1 to 3,
A resin pipe arranged such that all ends of an interface where the reinforcing layer and the pipe main body are in contact with each other are exposed in a flow path in the pipe main body or the hose. A method for manufacturing the resin pipe according to any one of claims 1 to 4, wherein
In the step of forming the pipe body by extruding the first resin material into a cavity of a mold having a molding surface following the outer peripheral surface of the pipe body, the pipe body is formed at the timing of forming the connection end. Forming the reinforcing layer on the connection end by extruding the second resin material toward the inner peripheral side, and blowing air into the pipe body and / or evacuating the molding surface. Method of manufacturing resin pipe.

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