Pipe joint

Abstract

A pipe joint 10 comprises an insertion part 12 inserted into a pipe outside a fuel tank. The insertion part 12 has: an outer peripheral part fixed to the outer surface of the fuel tank; an inner peripheral part formed of a material different from the outer peripheral part on the inner side of the outer peripheral part; and a bulging part 22 that is formed by the outer peripheral part and the inner peripheral part at the side of an insertion end 12a to be inserted into a pipe, and that bulges outward in the radial direction. The bulging part 22 has: a first bulging part formed by the outer peripheral part so as to bulge outward in the radial direction; and a second bulging part that is formed by the inner peripheral part so as to bulge outward in the radial direction, positioned closer to the insertion end 12a than the first bulging part, and exposed to the outer surface. A boundary between the outer peripheral part and the inner peripheral part is formed on the outer peripheral surface of the bulging part 22.

Description

Pipe fittings

[0001] The present invention relates to a pipe joint that is attached to a fuel tank.

[0002] Patent Document 1 discloses a welded joint for a fuel tank, which includes a joint body having a cylindrical tubular body and a barrier layer laminated on the surface of the joint body. The joint body is formed from a first resin material that has weldability to the wall surface of the fuel tank, and the barrier layer is formed from a second resin material that has better fuel permeation resistance than the first resin material. The barrier layer has a terminal portion formed so as to be exposed to the outside from the tip of the tubular body of the joint body. The terminal portion of the barrier layer is connected to a hose to form a seal.

[0003] Japanese Patent Application Laid-Open No. 2002-254938

[0004] In the technology disclosed in Patent Document 1, the pipe is cylindrical with a constant thickness all the way to the tip, so if the pipe is formed to be thin, the resin flow during molding will be poor, which could result in molding defects. Increasing the pipe's thickness is one way to prevent molding defects, but the outer diameter of the pipe cannot be increased due to restrictions on the diameter of the mating hose. If the pipe's thickness is increased while maintaining its outer diameter, the inner diameter of the fuel tank weld joint will be smaller, resulting in a reduced flow path area.

[0005] An object of the present invention is to provide a pipe joint that allows for good resin flow during molding and prevents a reduction in flow path area.

[0006] To solve the above problems, one aspect of the present invention is a pipe fitting that is attached to a mounting hole in a fuel tank and connected to a pipe, and that includes an insertion portion that is inserted into the pipe outside the fuel tank. The insertion portion has an outer circumferential portion that is fixed to the outer surface of the fuel tank, an inner circumferential portion that is formed inside the outer circumferential portion and is made of a material different from that of the outer circumferential portion, and a bulge portion that is formed by the outer circumferential portion and the inner circumferential portion at the insertion end side into the pipe and bulges outward in the radial direction. The bulge portion has a first bulge portion that is formed so as to bulge outward in the radial direction by the outer circumferential portion, and a second bulge portion that is formed so as to bulge outward in the radial direction by the inner circumferential portion and is located closer to the insertion end than the first bulge portion and is exposed to the outer surface. The outer circumferential surface of the bulge portion forms a boundary between the outer circumferential portion and the inner circumferential portion.

[0007] According to the present invention, it is possible to provide a pipe fitting that allows for good resin flow during molding and prevents a reduction in flow path area.

[0008] Fig. 2 is a perspective view of a pipe joint according to an embodiment; Fig. 3 is a perspective view of the pipe joint showing an enlarged view of the insertion portion side; Fig. 4 is a cross-sectional view of the pipe joint according to an embodiment; Fig. 5 is a cross-sectional view of the pipe joint showing an enlarged view of the insertion portion side;

[0009] 1 is a perspective view of a pipe fitting 10 according to an embodiment. The pipe fitting 10 is attached to a mounting hole of a fuel tank and connected to a pipe. The pipe fitting 10 forms a flow path for injecting fuel from the pipe to the fuel tank.

[0010] The pipe fitting 10 includes an insertion portion 12, a tank side cylindrical portion 14, a lid portion 16, an attachment portion 18, a stopper portion 20, and a collar. The insertion portion 12 is located at one end of the pipe fitting 10 and is inserted into a pipe outside the fuel tank. The insertion portion 12 has a bulge portion 22 on the insertion end 12a side.

[0011] The tank side tubular portion 14 is located at the other end of the pipe joint 10 and is inserted into the fuel tank. The lid portion 16 is provided so as to be able to open and close the opening of the tank side tubular portion 14. The lid portion 16 is kept in a closed state by a spring and opens when fuel is injected into the pipe joint 10.

[0012] The mounting portion 18 is formed in a flange shape that protrudes radially outward. The mounting portion 18 is fixed to the surface of the fuel tank by welding, adhesive, or the like. The mounting portion 18 is located between the insertion portion 12 and the tank side tubular portion 14.

[0013] The stopper portion 20 is located closer to the insertion portion 12 than the attachment portion 18 and protrudes radially outward. The stopper portion 20 abuts against the tip of the pipe to stop the pipe from being inserted.

[0014] 2 is an enlarged perspective view of the pipe fitting 10 showing the insertion portion 12 side. A collar 24 is disposed inside the insertion portion 12. The collar 24 is made of a metal material and has a cylindrical shape. The collar 24 can improve the rigidity of the insertion portion 12.

[0015] The crimped portions 26 are formed on the insertion end 12a side of the insertion portion 12, and are spaced apart in the circumferential direction. The crimped portions 26 bend a portion of the insertion portion 12 on the insertion end 12a side radially inward. The crimped portions 26 limit the axial movement of the collar 24 and prevent the collar 24 from coming off. Note that the crimped portions 26 are not limited to being formed partially, and may be formed around the entire circumference of the insertion end 12a.

[0016] The bulging portion 22 bulges outward in the radial direction. The bulging portion 22 has a maximum diameter portion 28, which is the largest diameter portion of the bulging portion 22. A boundary 30 between two materials is formed midway along the outer circumferential surface of the bulging portion 22.

[0017] Figure 3 is a cross-sectional view of the pipe fitting 10 of the embodiment. Figure 3 shows the pipe fitting 10 in an attached state, with the fuel tank 32, piping 34, and clamp 35 indicated by dashed lines. The tank side cylindrical portion 14 is inserted into the fuel tank 32 through a mounting hole 32a in the fuel tank 32. The mounting portion 18 is fixed to the surface of the fuel tank 32 by welding, for example.

[0018] The insertion portion 12 is inserted into a pipe 34. The pipe 34 is, for example, a rubber hose. The clamp 35 tightens the pipe 34, pressing the pipe 34 against the insertion portion 12. This prevents the insertion portion 12 and the pipe 34 from coming off. The collar 24 ensures rigidity that can withstand the tightening of the clamp 35.

[0019] The bulging portion 22 bulges outward in the radial direction on the side of the insertion end 12a into the pipe 34, and is formed around the entire circumference. A maximum diameter portion 28 of the bulging portion 22 is larger than the inner diameter of the pipe 34. Therefore, the bulging portion 22 is pressed against the inner peripheral surface of the pipe 34 when inserted into the pipe 34, sealing the insertion portion 12 and the pipe 34. The bulging portion 22 also makes it difficult for the pipe 34 to come off the insertion portion 12.

[0020] 4 is an enlarged cross-sectional view of the pipe fitting 10 showing the insertion portion 12 side. The components that make up the insertion portion 12 are formed from two materials by two-color molding. The insertion portion 12 has an outer peripheral portion 36 and an inner peripheral portion 38 made of different materials. The outer peripheral portion 36 is formed from a material that is easily welded to the outer surface of the fuel tank 32 and has better water resistance than the inner peripheral portion 38. The inner peripheral portion 38 is formed from a material that is more resistant to fuel permeation than the outer peripheral portion 36 and is harder than the outer peripheral portion 36. For example, the outer peripheral portion 36 is formed from high-density polyethylene, and the inner peripheral portion 38 is formed from polyamide.

[0021] The outer circumferential portion 36 and the inner circumferential portion 38 are formed in a cylindrical shape, and the inner circumferential portion 38 is formed inside the outer circumferential portion 36. The inner circumferential portion 38 has a step portion 44 that limits the movement of the collar 24 toward the rear. The radial height of the step portion 44 is formed to match the thickness of the collar 24.

[0022] The bulging portion 22 is formed by an outer circumferential portion 36 and an inner circumferential portion 38. The bulging portion 22 has a first bulging portion 40 formed by the outer circumferential portion 36 so as to bulge radially outward, and a second bulging portion 42 formed by the inner circumferential portion 38 so as to bulge radially outward. The second bulging portion 42 is located closer to the insertion end 12a than the first bulging portion 40 and is exposed on the outer surface. Therefore, the insertion end 12a is formed only by the inner circumferential portion 38, forming a single-layer portion consisting only of the inner circumferential portion 38. A boundary 30 between the outer circumferential portion 36 and the inner circumferential portion 38 is formed on the outer circumferential surface of the bulging portion 22. The boundary 30 is the portion where the outer circumferential portion 36 and the inner circumferential portion 38 come into contact at a position exposed on the outer circumferential surface of the bulging portion 22, and may also be referred to as an outer surface boundary.

[0023] When parts are formed by injecting resin material through injection molding, poor resin flow can occur at the end far from the fill position, potentially resulting in molding defects. By having both the outer peripheral portion 36 and the inner peripheral portion 38 form part of the bulge portion 22 on the insertion end 12a side, the tip has a bulged shape, improving resin flow to the tip and reducing molding defects. Furthermore, improving resin flow allows the insertion portion 12 to be thinner. Reducing the thickness of the insertion portion 12 also reduces the reduction in flow path area.

[0024] The bulging portion 22 has a tapered surface 22a whose outer circumferential surface decreases in diameter from the maximum diameter portion 28 toward the insertion end 12a. That is, the tapered surface 22a increases in diameter from the insertion end 12a toward the axial rear. The outer circumferential portion 36 covers the outer surface of the inner circumferential portion 38 at least up to the maximum diameter portion 28 of the bulging portion 22. The maximum diameter portion 28 contacts and seals the inner circumferential surface of the piping 34. Therefore, snow-melting agents containing calcium chloride or the like that enter from the outside are stopped by the outer circumferential portion 36, which forms the maximum diameter portion 28, and are prevented from acting on the inner circumferential portion 38. The boundary 30 is located midway along the tapered surface 22a.

[0025] The boundary 30 between the outer circumferential portion 36 and the inner circumferential portion 38 is located midway along the tapered surface 22a of the bulging portion 22. Since the first bulging portion 40 and the second bulging portion 42 have tapered surfaces 22a with the same inclination angle, the tapered surfaces 22a become uniform, facilitating insertion into the piping 34. The tapered surface 22a of the bulging portion 22 is formed uniformly and smoothly.

[0026] The boundary 30 between the outer circumferential portion 36 and the inner circumferential portion 38 is formed at a position overlapping the collar 24 in the axial direction. In other words, the collar 24 is positioned radially inward of the boundary 30 so as to overlap. Figure 4 shows the state before the crimped portion 26 is formed, with the collar 24 recessed further back than the position of the crimped portion 26. The bulge 22 on the insertion end 12a side from the collar 24 is formed of a single layer of the inner circumferential portion 38. Therefore, the crimped portion 26 can be formed more easily than when the insertion end 12a of the bulge 22 is two-layered.

[0027] The position of the boundary 30 does not have to be limited to the middle of the tapered surface 22a. For example, the boundary 30 between the outer circumferential portion 36 and the inner circumferential portion 38 may be formed at the position of the maximum diameter portion 28. On the outer circumferential surface of the bulging portion 22, the inner circumferential portion 38 is formed from the insertion end 12a to the position of the maximum diameter portion 28, which increases the rigidity of the bulging portion 22 and allows it to be pressed firmly against the piping 34, improving sealing performance. In addition, the outer circumferential portion 36 can prevent the intrusion of snow-melting agent.

[0028] The present invention is not limited to the above-described embodiments, and various modifications such as design changes may be made to the embodiments based on the knowledge of those skilled in the art, and such modified embodiments may also be included within the scope of the present invention.

[0029] In the embodiment, the pipe fitting 10 is shown to be bent, but is not limited to this. For example, the pipe fitting 10 may be formed in a cylindrical shape with a linear central axis. Furthermore, the shape of the fitting other than the insertion portion 12 does not need to be limited to the shape shown in FIG. 1.

[0030] The present invention relates to a pipe joint that is attached to a fuel tank.

[0031] 10 Pipe fitting, 12 Insertion portion, 12a Insertion end, 14 Tank side tube portion, 16 Lid portion, 18 Mounting portion, 20 Stopper portion, 22 Bulging portion, 22a Tapered surface, 24 Collar, 26 Crimped portion, 28 Maximum diameter portion, 30 Boundary, 32 Fuel tank, 32a Mounting hole, 34 Piping, 35 Clamp, 36 Outer periphery, 38 Inner periphery, 40 First bulging portion, 42 Second bulging portion, 44 Step portion.

Claims

1. A pipe fitting that is attached to a mounting hole of a fuel tank and connected to a pipe, comprising an insertion portion that is inserted into the pipe outside the fuel tank, the insertion portion having an outer peripheral portion that is fixed to the outer surface of the fuel tank, an inner peripheral portion that is formed inside the outer peripheral portion and is made of a material different from that of the outer peripheral portion, and a bulge portion that is formed by the outer peripheral portion and the inner peripheral portion at the insertion end side into the pipe and bulges outward in the radial direction, the bulge portion having a first bulge portion formed by the outer peripheral portion so as to bulge outward in the radial direction, and a second bulge portion formed by the inner peripheral portion so as to bulge outward in the radial direction, located closer to the insertion end than the first bulge portion and exposed to the outer surface, and the boundary between the outer peripheral portion and the inner peripheral portion is formed on the outer peripheral surface of the bulge portion.

2. A pipe joint according to claim 1, wherein the outer peripheral portion covers the outer surface of the inner peripheral portion at least up to the position of the maximum diameter of the bulging portion.

3. A pipe fitting as described in claim 1 or 2, characterized in that the bulging portion has a tapered surface 22a whose outer diameter decreases from the position of maximum diameter of the bulging portion toward the insertion end, and the boundary is located halfway along the tapered surface 22a.

4. A pipe joint according to claim 1 or 2, characterized in that the boundary is formed at the position of the maximum diameter of the bulging portion.

5. A pipe fitting according to claim 1 or 2, further comprising a cylindrical collar arranged inside the insertion portion, wherein the boundary is formed at a position overlapping with the collar in the axial direction.

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