JP2007064250A - Joining structure of resin pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely weld a resin pipe to a joint. <P>SOLUTION: The resin pipe 20 is formed of a plurality of layers having a straight part 21 and a joining enlarged part 22 enlarged at the end of the straight part 21. The joint 10 comprises a joining part 16 formed at one end of a pipe body 14 and joining the joining enlarged part 22. The inside of the end part of the joining enlarged part 22 is supported by the support wall 16b of the joint 10, and welded with a pipe side weld part 22b brought into surface contact with a joint side weld part 16a. Consequently, the resin pipe 20 is joined to the joint 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin pipe connection structure in which a resin pipe composed of a plurality of layers is connected to a joint.

Conventionally, in order to thermally weld one resin component, a flange is formed on one or both of the end portions of the resin component, and this flange is melted and welded with a hot plate or the like. A burr is generated in such a heat-welded portion, and a configuration in which a burr trap is provided in the vicinity of the flange is known in order to prevent the burr from entering the inner space or the like (Patent Documents 1 and 2). .
By the way, a configuration in which two or more resin pipes including a barrier layer in consideration of fuel permeation resistance are connected to a fuel tank joint or the like has been studied. The barrier layer of such a resin pipe may be difficult to weld to the mating joint.

JP 7-330081 A JP 2003-285375 A

  An object of the present invention is to provide a resin pipe connection structure that reliably connects a resin pipe formed of a plurality of layers to a joint in light of solving the above-described problems of the conventional technology.

The present invention made to solve the above problems
In the joint structure of the resin pipe in which the resin pipe formed from a plurality of layers is connected to the joint,
In the resin pipe, at least an inner layer of the plurality of layers is formed from the first resin material, and the tubular straight portion and the end portion of the straight portion are expanded toward the outer diameter side and bent to the inner side. A connection extension part with a part of the layer as a pipe-side weld,
The joint includes a tube body that forms a passage connected to the resin pipe, and a connection portion that is formed at one end of the tube body and connects the connection extension portion.
The connection portion is formed of a second resin material that can be welded to the first resin material and is formed along the outer peripheral portion of the end portion of the tubular body, and the joint side weld portion. A support wall disposed on the passage side and projecting in a cylindrical shape from the upper part of the tubular body in the longitudinal direction of the tubular body,
The resin pipe is connected to the joint by the support wall being inserted into the connection extension portion and welded in a state where the pipe side weld portion is in surface contact with the joint side weld portion. It is characterized by.

In the resin pipe connection structure according to the present invention, the resin pipe composed of a plurality of layers is connected to the joint by welding the pipe-side welded portion to the joint-side welded portion of the joint. On the passage side of the joint-side welded portion, a support wall is provided that protrudes in a cylindrical shape in the longitudinal direction from the upper part of the tube, and this support wall prevents burrs generated by welding from entering the passage. As a result, it does not cause a problem.
Further, since the support wall is inserted into the connection expansion portion formed by expanding the diameter of the end portion of the resin pipe, it is easy to make the inner wall of the joint and the passage of the resin pipe substantially flush with each other, This does not increase the resistance flowing through the passage.
Since the pipe-side welded portion of the resin pipe uses the inner layer of the resin pipe formed from a resin material that can be welded to the joint-side welded portion of the joint, there is no need to separately provide a member for welding, High welding strength can be obtained with a simple configuration. Moreover, the resin pipe is welded at the pipe-side weld portion formed by a part of the inner layer side even when a resin material having excellent fluid resistance permeation is arranged in the outer layer from the inner layer. It is not necessary to consider the weldability with the side welds.

As a preferred aspect of the present invention, the connection portion can be configured to include a burr holding portion formed in a recess between the support wall and the pipe-side weld portion. Since the burr holding part traps the burr that flows out at the time of welding and does not put it out to the passage side, it does not hinder the flow of fluid.
Further, as another preferred embodiment, the connection expansion portion may be formed in a flare shape (a trumpet shape or a morning glory shape. The flare shape connection expansion portion is continuous with the straight portion and has a diameter expanded from the straight portion. It can be easily formed by forming an enlarged diameter portion and cutting the enlarged diameter portion.

  The first resin material and the second resin material may be a resin material that can be welded together, that is, the same resin material, or a resin material that is welded together by chemical bonding or the like.

  In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the present invention will be described below.

A. First Embodiment (1) Structure of Resin Pipe Connection Structure FIG. 1 is a sectional view showing a resin pipe connection structure according to a first embodiment of the present invention. The present embodiment is applied to a connection portion between a fuel tank joint of an automobile and a resin pipe (inlet pipe). In FIG. 1, a joint 10 is welded to the outer wall of the fuel tank FT, and a resin pipe 20 is welded to the joint 10.
The surface of the fuel tank FT is formed of a composite resin material containing polyethylene, and is formed in three layers by a blow molding method. That is, the fuel tank FT is formed by laminating a tank inner layer FT1, a tank outer layer FT2, and a barrier layer FT3 interposed between the tank inner layer FT1 and the tank outer layer FT2. The tank inner layer FT1 and the tank outer layer FT2 are made of high-density polyethylene and mainly have a function as a structural material that ensures the mechanical strength of the fuel tank. On the other hand, the barrier layer FT3 is formed of ethylene vinyl alcohol (EVOH) or polyamide (PA) having excellent fuel permeation resistance, and has a function as a shielding material that prevents permeation of fuel vapor.

(2) Configuration of each part of resin pipe connection structure (2) -1 Joint 10
The joint 10 is a joint for closing the attachment hole FTc of the fuel tank FT and connecting it to the resin pipe 20. FIG. 2 is a cross-sectional view showing a state before the joint 10 is welded to the fuel tank FT. In FIG. 2, the joint 10 includes a closing plate 12 and a tubular body 14 protruding from the center of the closing plate 12.
An annular welding end 12 a that is welded to the tank upper wall FTa of the fuel tank FT is formed at the lower outer periphery of the closing plate 12. The pipe body 14 has a passage 14a connected to the fuel tank FT, and includes a connection portion 16 for connecting the resin pipe 20 to the upper end portion thereof. The connection portion 16 includes a joint-side weld portion 16a, a support wall 16b, and a burr holding portion 16c formed between the joint-side weld portion 16a and the support wall 16b. The joint-side weld portion 16 a is a portion for welding with the connection extension portion 22 of the resin pipe 20, and is formed along the outer peripheral portion of the end portion of the tube body 14. The support wall 16b is disposed in the passage 14a from the joint-side welded portion 16a and protrudes in a cylindrical shape from the upper portion of the tube body 14 in the longitudinal direction of the tube body 14. The burr holding part 16c is a burr trap formed in a recess between the joint-side welded part 16a and the support wall 16b.
The resin material (second resin material) forming the joint 10 is determined in consideration of the weldability with the fuel tank FT, the fuel permeation resistance, the adhesion with the resin pipe 20, and the like. Medium density polyethylene or the like can be used.

(2) -2 Resin pipe 20
The resin pipe 20 is formed of five layers including a barrier layer formed of a resin material having excellent fuel permeation resistance. That is, the resin pipe 20 includes an inner layer 20a, an adhesive layer 20b, a barrier layer 20c, an adhesive layer 20d, and an outer layer 20e, and simultaneously extrudes the resin material forming them and shapes it into a pipe shape, which will be described later. Manufactured by a corrugated molding method.
Here, for the inner layer 20a, high-density polyethylene (HDPE) is selected mainly for resistance to fuel (first resin material). For the barrier layer 20c, an ethylene vinyl alcohol copolymer (EVOH) is selected for the main purpose of fuel permeation resistance (third resin material). For the outer layer 20e, high density polyethylene (HDPE) is selected mainly for mechanical strength. For the adhesive layers 20b and 20d, maleic acid-modified modified polyethylene (m-PE) is selected as a polar functional group for the main purpose of adhering to both the barrier layer 20c and the inner layer 20a or the outer layer 20e. Since the modified polyethylene is a similar polyethylene, it is welded to the HDPE of the outer layer 20e and the inner layer 20a, and is bonded to EVOH by chemical adhesion, and thus has an action of adhering these layers.
Further, as the thickness of each layer of the resin pipe 20, when the thickness of the straight portion 21 is 4 mm, the inner layer 20a is 1.0 mm, the adhesive layers 20b and 20d are 0.5 mm, and the barrier layer 20c is 0.3 mm. The outer layer 20e can be adjusted to 1.7 mm.
A connection expansion portion 22 is formed at the end of the resin pipe 20 by expanding the diameter of the end of the straight portion 21. The connection expansion portion 22 includes a flare portion 22a that is gradually expanded in diameter. The front end portion of the flare portion 22a is bent to form a pipe-side weld portion 22b formed by a part of the inner layer 20a. The pipe-side welded part 22b is a part that is thermally welded to the joint-side welded part 16a of the joint 10.

(2) -3 Manufacturing method of resin pipe 20 The resin pipe 20 is manufactured by the process demonstrated below. FIG. 3 is a schematic configuration diagram illustrating a pipe manufacturing apparatus 30 for manufacturing the resin pipe 20. The pipe manufacturing apparatus 30 can form the resin pipe 20 continuously with different cross-sectional shapes in the straight portion 21 and the connection expansion portion 22, and uses a so-called corrugated mechanism. The pipe manufacturing apparatus 30 includes a tube extruding unit 40 for extruding the extruded tube 20P, a molding die unit 50 for shaping the outer peripheral portion of the extruded tube 20P extruded from the tube extruding unit 40, and a molding die. And a transfer device 70 for transferring the mold unit 50 in a loop shape.
The tubular body extrusion unit 40 includes an extrusion device for extruding five layers of resin material concentrically from the resin pipe 20, and the extrusion device includes a screw, a cylinder, a die, and the like. The molding die unit 50 includes a plurality of molds 61A and 61B each having a molding surface following each part of the resin pipe 20, that is, a molding surface following the shape of the straight portion 21 and the connection expansion portion 22, respectively. Each of the extruded tube bodies 20P is disposed so as to pass through the transport path FL along which the extruded tube body 20P is transported. The mold 61 is composed of split molds divided along the central axis of the extruded tubular body 20P to be conveyed, and these split molds are each in a loop shape and are arranged so as to be clamped. . A suction passage connected to a suction pump (not shown) is opened on the molding surfaces of the molds 61A and 61B.

  In order to manufacture the resin pipe 20 by the pipe manufacturing apparatus 30, first, the extruded tube body 20P is extruded by the tube body extrusion unit 40, and then the molds 61A and 61B of the molding mold unit 50 are conveyed in a loop shape. To do. At this time, the dies 61A and 61B are blown into the extruded tube body 20P, and the molding surfaces of the dies 61A and 61B are sucked by the suction pump, whereby the straight portion 21 and the enlarged diameter portion 22A (see FIG. 4). ) Is shaped. By repeating such a continuous process and further cutting the shaped extruded tube 20P at the end of the enlarged diameter portion 22A as shown in FIG. 4, a connection expansion portion 22 continuous to the straight portion 21 is formed. The

(3) Resin Pipe Connection Structure Connection Operation Next, an operation of mounting the joint 10 on the tank upper wall FTa of the fuel tank FT will be described. In FIG. 2, the lower end of the welding end 12a of the joint 10 is melted by a hot plate (not shown), and melted by a hot plate (not shown) along the periphery of the mounting hole FTc of the fuel tank FT to form a weld surface. . Press the welding end against the welding surface. Since both the welding end 12a and the welding surface are formed of polyethylene, they are welded together when cooled and solidified as shown in FIG.

  Then, in order to connect the resin pipe 20 to the joint 10 as shown in FIG. 5, first, the hot plate HP is applied to the joint-side welded portion 16a of the connecting portion 16 of the joint 10 and the pipe-side welded portion 22b of the resin pipe 20. And melt that part. Subsequently, as shown in FIG. 6, the pipe-side welded portion 22 b of the resin pipe 20 is pressed against the joint-side welded portion 16 a of the joint 10. As a result, the joint-side welded portion 16a and the pipe-side welded portion 22b are both formed of polyethylene, so that they are welded together when cooled and solidified.

(4) Actions and effects of the embodiment (4) -1 As shown in FIG. 6, on the passage side of the joint-side welded portion 16a, a support wall protruding in a cylindrical shape in the longitudinal direction from the upper portion of the tube body 14 16b is provided, and the support wall 16b prevents the burr BR generated by the welding of the pipe-side welded portion 22b and the joint-side welded portion 16a from entering the passage 14a. Moreover, a burr holding portion 16c formed from a recess is provided on the outer peripheral side of the support wall 16b, so that the burr that has flowed out during welding is trapped and does not go out to the side of the passage 14a. Therefore, since the burr BR does not enter the fuel tank through the passage 14a, it does not cause a problem.
(4) -2 Since the support wall 16b is inserted into the enlarged connection extension portion 22, the inner wall of the passage between the joint 10 and the resin pipe 20 is substantially flush with the passage of the resin pipe 20 and the joint. The flow path resistance that flows in the vicinity of the ten connection points is not increased.
(4) -3 Since the pipe-side welded portion 22b of the resin pipe 20 uses the inner layer 20a of the resin pipe 20 formed from a resin material that can be welded to the joint-side welded portion 16a, a member for welding separately. Therefore, a high welding strength can be obtained with a simple configuration. Further, when the barrier layer 20c is disposed outside the inner layer 20a to increase the fuel permeation resistance, the barrier layer 20c may be a resin material that is difficult to weld to the joint-side welded portion 16a. Becomes the pipe-side weld portion 22b and does not affect the weldability of the joint 10.
(4) -4 As shown in FIG. 6, the flare-shaped connection extended portion 22 forms a diameter-enlarged portion 22 </ b> A that is continuous with the straight portion 21 and is expanded from the straight portion 21. It can be easily formed by cutting.

B. Second Embodiment FIG. 7 is a cross-sectional view showing a resin pipe connection structure according to a second embodiment. This embodiment is characterized by a configuration applied to a quick connector. That is, the connector 100 connects the resin pipe 20 and the pipe P protruding from the tank, and seals between the inner connecting portion 110, the outer connecting body 120, and the pipe P and the inner connecting portion 110. And a seal member 130. The inner connecting portion 110 is a member that joins the resin pipe 20, and includes a small diameter portion 112 and a large diameter portion 114 that is expanded from the small diameter portion 112, and a step portion 116 therebetween. A connecting portion 118 is formed at the end of the small diameter portion 112. The connection part 118 is a part where the resin pipe 20 is welded, and has the same configuration as the connection part 16 of FIG. An outer coupling body 120 is externally mounted on the large-diameter portion 114, and an engagement claw 122 of the outer coupling body 120 is engaged with the step portion 116. Further, an engaging claw 124 is formed at the other end portion of the outer coupling body 120, and the pipe P is prevented from being pulled out by engaging with the bulge Pa of the pipe P. Thus, if it is the structure which can join the resin pipe 20 as a coupling, it is applicable also to a connector.

C. Other Embodiments The present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.
(1) Although the said Example demonstrated the structure which adhere | attaches a barrier layer, an inner layer, and an outer layer using an adhesion layer, it is not restricted to this, Adhesion | attachment with a barrier layer using modified PE as a resin material of an inner layer and an outer layer By imparting the properties, the adhesive layer can be eliminated, and a simple configuration of three layers can be obtained.
(2) In the said Example, although the resin pipe 20 was shape | molded by the corrugated molding method, you may use not only this but the extrusion blow molding method.
(3) In the above embodiment, the filler pipe is applied. However, the filler pipe may be any place such as a filler neck and a resin pipe having an injection port, or the vicinity of the outer wall of the fuel tank. Further, as other uses, it can be applied to a water pipe of an engine cooling water system.
(4) As long as the fuel tank is connected to the outside, it can be applied to various joints, for example, a fuel cutoff valve for ventilating the fuel tank and the outside.
(5) Although the joint in the said Example was formed from single resin material from PE, you may provide a barrier layer in the location except not only this but the joint side welding part 16a, the welding end 12a, etc. FIG. That is, as shown in FIG. 8, the joint 10 </ b> B may be formed by two-color molding from the outer layer 10 </ b> Ba welded to the connection extension 22 of the fuel tank FT and the resin pipe 20 and the inner layer 10 </ b> Bb as a barrier layer. The outer layer 10Ba uses modified polyethylene modified with maleic acid, and the inner layer 10Bb uses EVOH as a barrier layer, which can be integrated by a two-color molding method.
(6) In the above-described embodiment, an example of heat welding using a hot plate has been described as means for heat welding. However, the present invention is not limited to this, and various welding means such as ultrasonic welding and laser welding can be used.

It is sectional drawing which shows the connection structure of the resin pipe concerning this invention. It is explanatory drawing which shows the state before welding a joint to a fuel tank. It is a schematic block diagram explaining the pipe manufacturing apparatus for manufacturing a resin pipe. It is explanatory drawing explaining the process of manufacturing a resin pipe. It is explanatory drawing explaining the process of connecting a resin pipe to a coupling. It is explanatory drawing explaining the connection state of a resin pipe and a coupling. It is sectional drawing which shows the connection structure of the resin pipe concerning 2nd Example. It is sectional drawing which shows the connection structure of the resin pipe concerning the modification of 1st Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Joint 12 ... Closure board 12a ... Weld end 14 ... Pipe body 14a ... Passage 16 ... Connection part 16a ... Joint side weld part 16b ... Support wall 16c. ..Burr holding part 20 ... resin pipe 20P ... extruded tube 20a ... inner layer 20b ... adhesive layer 20c ... barrier layer 20d ... adhesive layer 20e ... outer layer 21 ... Straight part 22 ... Connection expansion part 22A ... Diameter expansion part 22a ... Flare part 22b ... Pipe side welding part 30 ... Pipe manufacturing equipment 40 ... Pipe body extrusion unit 50 ... Molding Mold unit 61 ... Mold 61A, 61B ... Mold 70 ... Transfer device 100 ... Connector 110 ... Inner connecting part 112 ... Small diameter part 114 ... Large diameter part 116 ... Step portion 118 ... Connection portion 120 ... Outer coupling body 122 ... engagement claw 124 ... engagement claw 130 ... sealing member 10B ... joint 10Ba ... outer layer 10Bb. .. Inner layer P ... Pipe Pa ... Bulge HP ... Plate FT ... fuel tank FT1 ... tank inner FT2 ... tank outer FT3 ... barrier layer FTa ... tank upper wall FTc ... mounting hole

Claims (5)

In the joint structure of the resin pipe in which the joint (10) is connected to the resin pipe (20) formed from a plurality of layers,
In the resin pipe (20), at least the inner layer of the plurality of layers is formed of the first resin material, and the tubular straight portion (21) and the end portion of the straight portion (21) are expanded to the outer diameter side. A connecting extension part (22) having a pipe-side weld part (22b) with a part of the inner layer being bent and bent,
The joint (10) includes a pipe (14) that forms a passage (14a) connected to the resin pipe (20), and one end of the pipe (14), and the connection extension (22). A connecting portion (16) for connecting
The connecting portion (16) is formed of a second resin material that can be welded to the first resin material and is formed along the outer peripheral portion of the end portion of the tubular body (14) (16a). ) And a support wall disposed in the side of the passage (14a) from the joint-side welded portion (16a) and projecting in a cylindrical shape from the upper portion of the tube (14) in the longitudinal direction of the tube (14) ( 16b)
The support wall (16b) is inserted into the connection extension portion (22), and the pipe side weld portion (22b) is welded in a state of surface contact with the joint side weld portion (16a). The resin pipe (20) is connected to the joint (10);
A resin pipe connection structure characterized by the above. In the connection structure of the resin pipe according to claim 1,
The connection part (16) is a resin pipe connection structure including a burr holding part (16c) formed in a recess between the support wall (16b) and the joint-side weld part (16a). In the connection structure of the resin pipe according to claim 1,
The connection extension part (22) is a resin pipe connection structure having a flare shape. In the connection structure of the resin pipe according to claim 3,
The resin pipe (20) is formed by forming an enlarged diameter portion (22A) that is continuous with the straight portion (21) and has an enlarged diameter from the straight portion (21), and then cutting the enlarged diameter portion (22A). A resin pipe connection structure in which a connection extension (22) is formed. In the resin pipe connection structure according to any one of claims 1 to 4,
The resin pipe is a resin pipe connection structure including a barrier layer formed of a third resin material having excellent fluid permeation resistance outside the inner layer.

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