Pipe connection structure

Abstract

To provide a pipe connection structure configuring an earth path improving insertion hardness of a pipe while keeping electric connectivity.SOLUTION: A pipe connecting portion 23 is equipped with a hollow base portion 24, and a hollow pipe connection body portion 25 into which a pipe tip end portion 51 of a breather pipe 50 communicating to a tip end side of the base portion 24 can be inserted. On the base portion 24, an earth connecting portion 31 is formed, which has a cross-section projecting out from an outer peripheral surface 29 of the base portion 24 outward and to the pipe connection body portion 25 side in a generally L-shape and is formed with a pressing portion 32 pressing a conductive layer 52 of the breather pipe 50 from the outside of the breather pipe 50. On an outer peripheral surface 29 of the pipe connection body portion 25, a projection strip 28 is formed which presses the breather pipe 50 from the inside, on except for a proximal portion 29a with the pressing portion 32 and near the proximal portion 29a. A distance between the pressing portion 32 and the proximal portion 29a of the pipe connection body portion 25 is greater than a wall thickness of the breather pipe 50.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a pipe connection structure that forms an earth path (electrical connection path) from a pipe connection part to a pipe used in fuel piping of a vehicle such as an automobile when the pipe is inserted into and connected to the pipe connection part. Note that the "pipe" is also called a "hose." [Background technology]

[0002] For example, in an automobile, when fuel is supplied to a fuel tank through a plastic or rubber fuel pipe connected to a filler neck, a mechanism is adopted that grounds static electricity to the vehicle body to eliminate the discomfort caused by static electricity when a charged person grabs the fuel cap.

[0003] One known earthing mechanism is a technology that creates an earth path by making the outer layer of a resin or rubber fuel pipe into a conductive layer with added carbon (Patent Document 1). To create this earth path, it is important to ensure that the filler neck and the resin or rubber fuel pipe are electrically connected securely.

[0004] Patent Document 2 discloses the following pipe connection structure as a configuration for reliably connecting this filler neck to a resin or rubber fuel pipe: Fig. 8 is a half cross-sectional view in the pipe insertion direction showing the vicinity of earth connection part 31 of pipe connection part 23 of filler neck 20, and Fig. 9 is a cross-sectional view in the direction perpendicular to the insertion direction of breather pipe 50, showing the vicinity of earth connection part 31 of pipe connection part 23.

[0005] 8 and 9, a filler neck 20 having a pipe connection part 23 formed from a conductive resin is connected to a breather pipe 50 which is connected to the pipe connection part 23 and has an outer layer (conductive layer 52) formed from a conductive resin. In the pipe connection part structure which constitutes an earth path from the filler neck 20 to the breather pipe 50, the pipe connection part 23 has a pipe connection main body 25 into which the pipe connection end 51 of the breather pipe 50 can be inserted from its tip to its base which is located at a predetermined length, a pipe slip-out prevention projection 26 which protrudes from the outer peripheral surface of the pipe connection main body 25 in an annular shape and has an outer diameter larger than the inner diameter of the breather pipe 50, and a pressing part 32 on which an earth connection part 31 protrudes from the base on the outer peripheral surface of the pipe connection main body 25 in a substantially L-shaped cross section and which forms an insertion gap 31S between the earth connection part 31 and the outer peripheral surface of the pipe connection main body 25.

[0006] The tip of the pipe connection end 51 of the breather pipe 50, which has been pressed in over the pipe slip-out prevention protrusions 26, is pressed into the insertion gap 31S to electrically connect with the outer layer of the pipe connection end 51. The pressing portion 32 has a reference surface 32a that is formed so that the radial height h1 of the insertion gap 31S is equal to or smaller than the wall thickness t1 of the end of the pipe connection end 51, and a connecting protrusion 32b that protrudes from the reference surface 32a to narrow a part of the insertion gap 31S and presses the outer layer of the pipe connection end 51. The connecting protrusion 32b is formed in a mountain range shape in the insertion direction of the breather pipe 50.

[0007] On the other hand, the pipe connection body 25 has a mountain-like protrusion 28 formed on the outer circumferential surface of the pipe connection body 25 at a position facing the connection projection 32b.

[0008] As a result, the connection protrusion 32b narrows the pipe connection end 51 of the breather pipe 500 together with the protrusion 28, thereby penetrating into the conductive layer 52 of the outer layer of the breather pipe 50, increasing the contact area between the earth connection portion 31 and the conductive layer 52, and improving electrical connectivity. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 11-118073 [Patent Document 2] JP 2011-131824 A Summary of the Invention [Problem to be solved by the invention]

[0010] As shown in FIG. 9, the electrical connectivity is improved by forming the pressing portion 32 having the reference surface 32a satisfying h1≦t1, the connecting protrusion 32b formed below the reference surface 32a, and the protrusion 28 having the uppermost portion facing the lowermost portion of the connecting protrusion 32b of the pressing portion 32 in the pipe connection body 25. However, in the portion of the pressing portion 32 where the connecting protrusion 32b formed below the reference surface 32a and the protrusion 28 having the uppermost portion facing the lowermost portion of the connecting protrusion 32b of the pressing portion 32 are formed, the distance between the connecting protrusion 32b and the protrusion 28 is very narrow, so that it is difficult to insert the breather pipe 50.

[0011] The inventors discovered that filler pipes and breather pipes used as fuel pipes for vehicles such as automobiles have high hardness, and that when a protruding portion of a pipe connection part has a ring-shaped cross section perpendicular to the pipe connection direction, the pipe has poor conformability to the shape of the protruding portion, and developed the present invention by utilizing the poor conformability. The present invention provides a pipe connection structure that forms an earth path that improves the difficulty of inserting a pipe while maintaining electrical connectivity. [Means for solving the problem]

[0012] In order to solve the above problem, the present invention of claim 1 provides a pipe connection structure in which a pipe having a conductive layer on its outer layer that has been given conductivity is connected to a pipe connection part made of a conductive resin used in fuel piping of a vehicle such as an automobile, and an earth path is formed from the pipe connection part to the pipe, the pipe connection part having a hollow base and a hollow pipe connection main body into which a pipe connection end of a pipe communicating with the tip side of the base can be inserted up to a base located at a predetermined length, the pipe connection main body has an outer peripheral surface formed with a pipe removal prevention protrusion that has an outer diameter larger than the inner diameter of the pipe and protrudes in an annular shape, the base has an earth connection part formed with a pressing part that protrudes outward from the outer peripheral surface of the base and toward the pipe connection main body in a substantially L-shaped cross section in the pipe insertion direction and presses the conductive layer of the pipe from the outside, and the pipe connection structure is characterized in that a protrusion that presses the pipe from the inside is formed on the outer peripheral surface of the pipe connection main body in a cross section perpendicular to the pipe insertion direction other than a part closest to the pressing part and in the vicinity of the closest part.

[0013] In the present invention of claim 1, a pipe connection main body of a pipe connection part formed from a conductive resin used for fuel piping of vehicles such as automobiles is provided on the outer surface of the pipe connection body, which has an outer diameter larger than the inner diameter of the pipe and protrudes in a ring shape.Therefore, when the pipe connection end of the pipe is inserted into the pipe connection part, the pipe removal prevention protrusion bites into the inner wall of the pipe connection end to prevent it from coming out.

[0014] On the other hand, on the outer peripheral surface of the pipe connection main body, in a cross section perpendicular to the insertion direction of the pipe, other than the portion closest to the pressing portion, and in the vicinity of the closest portion, a protrusion that presses the pipe from the inside is formed. Therefore, the protrusion formed in the vicinity of the closest portion presses the pipe from the inside and deforms the pipe, but the pipe has poor ability to conform to the shape of the protrusion portion, and the pipe bulges and deforms toward the pressing portion of the earth connection portion so that a gap is formed between the protrusion and above the closest portion.

[0015] At this time, the base of the pipe connection body is formed with an earth connection part that protrudes outward from the outer circumferential surface of the base and toward the pipe connection body side in a substantially L-shaped cross section in the pipe insertion direction and has a pressing part that presses the conductive layer of the pipe from the outside, so that the pressing part of the earth connection part and the conductive layer of the outer layer of the pipe can be brought into contact with each other. As a result, it is possible to configure and secure an earth path from the pipe connection part to the pipe without narrowing the gap between the pressing part of the earth connection part and the closest part of the pipe connection part as in the background art, and at the same time, the pipe can be easily inserted into the pipe connection part.

[0016] The present invention of claim 2 is a pipe connection structure according to the invention of claim 1, in which the cross section of the pressing portion perpendicular to the pipe insertion direction is approximately trapezoidal with the short side on the conductive layer side of the pipe, and the cross section of the protrusion perpendicular to the pipe insertion direction is formed from the outer peripheral surface of the pipe connection main body to be approximately parallel to the short side and longer than the short side.

[0017] In the present invention of claim 2, the cross section of the pressing part perpendicular to the pipe insertion direction is substantially trapezoidal with the short side on the conductive layer side of the pipe, and the cross section of the protrusion perpendicular to the pipe insertion direction is formed from the outer circumferential surface of the pipe connection main body to be substantially parallel to the short side and longer than the short side, so that the pipe bulges and deforms toward the pressing part of the earth connection part so as to form a gap that is highest above the closest part of the protrusion. As a result, the pressing part of the earth connection part and the conductive layer of the outer layer of the pipe can be brought into contact with each other, so that an earth path can be formed and secured from the pipe connection part to the pipe, and at the same time, the pipe can be easily inserted into the pipe connection part.

[0018] The present invention of claim 3 is a pipe connection structure according to claim 1, wherein the cross section of the pressing portion perpendicular to the pipe insertion direction is an approximately rectangular shape with an arc shape protruding toward the conductive layer side of the pipe, and the cross section of the protrusion perpendicular to the pipe insertion direction is an arc shape protruding from the outer peripheral surface of the pipe connection main body.

[0019] In the present invention of claim 3, the cross section of the pressing portion in a direction perpendicular to the pipe insertion direction is an approximately rectangular shape in which an arc shape is formed protruding toward the conductive layer of the pipe, and the cross section of the protrusion formed in the portion other than the closest portion to the pressing portion and in the vicinity of the closest portion is an arc shape protruding from the outer circumferential surface of the pipe connection main body, so that the protrusion presses the pipe from the inside and deforms the pipe, but the pipe has poor ability to conform to the shape of the protrusion portion, and the pipe bulges and deforms toward the pressing portion of the earth connection portion so that a gap is formed between the closest portion and the pipe.

[0020] On the other hand, the cross section of the pressing part perpendicular to the pipe insertion direction is a substantially rectangular shape with an arc shape formed on the conductive layer side of the pipe, so that the arc shape protruding toward the pressing part side of the earth connection part comes into contact with the pipe bulging toward the pressing part side of the earth connection part. As a result, the pressing part of the earth connection part and the conductive layer of the outer layer of the pipe can be brought into contact with each other, so that an earth path can be formed and secured from the pipe connection part to the pipe, and at the same time, the pipe can be easily inserted into the pipe connection part.

[0021] The present invention of claim 4 provides the pipe connection structure of claim 3, wherein the protrusions are formed at positions approximately symmetrical with respect to the portion closest to the pressing portion.

[0022] In the present invention of claim 4, the protrusions are formed at positions approximately symmetrical with respect to the closest part to the pressing part, so the pipe deforms so that the gap is on the closest part between the protrusions and is formed symmetrical with respect to the closest part. And, since an arc shape that protrudes toward the pressing part of the earth connection part exists on the closest part to the pressing part, the pressing part of the earth connection part and the conductive layer of the outer layer of the pipe can be abutted, so that an earth path can be formed and secured from the pipe connection part to the pipe, and at the same time, the pipe can be easily inserted into the pipe connection part.

[0023] The present invention of claim 5 is a pipe connection structure according to claims 1 to 4, in which the distance between the pressing part of the earth connection part and the closest part of the pipe connection body is longer than the wall thickness of the pipe.

[0024] As described above, filler pipes and breather pipes used as fuel piping in vehicles such as automobiles have a high hardness, and when a portion protruding from the ring shape is present in a cross section perpendicular to the pipe connection direction at the pipe connection part, the pipe has poor conformability to the shape of the protruding portion, and the pipe swells and deforms such that a gap is formed between the pipe and the protrusion.

[0025] In the present invention of claim 5, even if the distance between the pressing portion of the earth connection portion and the nearest portion of the pipe connection main body is made longer than the thickness of the pipe, the pressing portion of the earth connection portion can be abutted against the conductive layer of the outer layer of the pipe, so that an earth path can be configured and secured from the pipe connection portion to the pipe, and at the same time, the pipe can be easily inserted into the pipe connection portion. Effect of the Invention

[0026] A pipe connection body of a pipe connection part made of a conductive resin used in fuel piping of vehicles such as automobiles has a ring-shaped pipe pull-out prevention protrusion formed on the outer surface thereof, the ring-shaped pipe pull-out prevention protrusion having an outer diameter larger than the inner diameter of the pipe. Therefore, when the pipe connection end of the pipe is inserted into the pipe connection part, the pipe pull-out prevention protrusion bites into the inner wall of the pipe connection end to prevent it from pulling out.

[0027] On the other hand, on the outer peripheral surface of the pipe connection main body, in a cross section perpendicular to the insertion direction of the pipe, other than the portion closest to the pressing portion, and in the vicinity of the closest portion, a protrusion that presses the pipe from the inside is formed. Therefore, the protrusion formed in the vicinity of the closest portion presses the pipe from the inside and deforms the pipe, but the pipe has poor ability to conform to the shape of the protrusion portion, and the pipe bulges and deforms toward the pressing portion of the earth connection portion so that a gap is formed between the protrusion and above the closest portion.

[0028] At this time, the base of the pipe connection body is formed with an earth connection part that protrudes outward from the outer circumferential surface of the base and toward the pipe connection body side in a substantially L-shaped cross section in the pipe insertion direction and has a pressing part that presses the conductive layer of the pipe from the outside, so that the pressing part of the earth connection part and the conductive layer of the outer layer of the pipe can be brought into contact with each other. As a result, it is possible to configure and secure an earth path from the pipe connection part to the pipe without narrowing the gap between the pressing part of the earth connection part and the closest part of the pipe connection part as in the background art, and at the same time, the pipe can be easily inserted into the pipe connection part. [Brief description of the drawings]

[0029] [Figure 1] 1 is a schematic diagram showing a fuel supply device for supplying fuel to a fuel tank according to an embodiment of the present invention. [Diagram 2] 2 is an enlarged cross-sectional view of a portion of a filler neck, a filler pipe, and a breather pipe shown in FIG. 1. [Diagram 3] 3 is a half sectional view showing a connection portion between a pipe connection part and a breather pipe (inside an ellipse in FIG. 2). FIG. [Figure 4] FIG. 2 is a perspective view showing the vicinity of an earth connection portion of the pipe connection portion of the first embodiment of the present invention. [Diagram 5] 5 is a cross-sectional view of the pipe connection part of FIG. 4 in the vicinity of the earth connection part, taken in a direction perpendicular to the insertion direction. [Figure 6] FIG. 11 is a perspective view showing the vicinity of an earth connection portion of a pipe connection portion according to a second embodiment of the present invention. [Figure 7] 7 is a cross-sectional view of the pipe connection part of FIG. 6 in the vicinity of the earth connection part, taken in a direction perpendicular to the insertion direction. [Figure 8] FIG. 1 is a half cross-sectional view showing a conventional connection portion between a pipe connection part and a breather pipe (Patent Document 2). [Figure 9] 9 is a cross-sectional view of the pipe connection part of FIG. 8 in the vicinity of the earth connection part, taken in a direction perpendicular to the insertion direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] This embodiment describes a pipe connection structure that constitutes an earth path that earths static electricity to the vehicle body in order to eliminate discomfort caused by static electricity when a charged person grasps a fuel cap 60 when fuel is supplied from a fuel supply device 10 of an automobile to a fuel tank. Note that the same reference numbers are used for the same parts as in the background art.

[0031] (1) Schematic configuration of the fuel supply device 10 1 is a schematic diagram showing a fuel supply device 10 for supplying fuel to a fuel tank according to an embodiment of the present invention. The fuel supply device 10 includes a fuel cap 60, a filler neck 20, a filler pipe 40 connecting the filler neck 20 to a fuel tank (not shown), a breather pipe 50 for ventilating the inside of the fuel tank to the outside during refueling, a pipe holder 80 for attaching both the filler pipe 40 and the breather pipe 50 to a vehicle body member (not shown), and a tank connecting member (not shown) for connecting the ends of the filler pipe 40 and the breather pipe 50 to the fuel tank. The filler pipe 40 and the breather pipe 50 are connected to the filler neck 20 at their pipe connection ends 41, 51.

[0032] The filler pipe 40 and the breather pipe 50 are both resin pipes and are made of multiple resin materials, namely, an inner layer made of high-density polyethylene with excellent fuel permeability resistance, and an outer layer made of polyethylene that has been made conductive by adding carbon or the like to the outer layer, forming a conductive layer 52 (Figure 3).

[0033] With this configuration, when fuel cap 60 is removed from filler neck 20 and fuel is poured into filler neck 20 from a fuel gun during refueling, the fuel is supplied to a fuel tank (not shown) through a fuel supply passage formed by filler neck 20 and filler pipe 40. At this time, breather pipe 50 allows fuel vapor in the fuel tank to escape from the fuel tank, smoothing the supply of fuel, and also acts as part of an earth path to remove static electricity charged to the human body. The configuration of each part will be explained below.

[0034] (2) Filler Neck 20 Fig. 2 is an enlarged cross-sectional view of a portion of the filler neck 20, the filler pipe 40, and the breather pipe 50 shown in Fig. 1. In Fig. 2, the filler neck 20 includes a neck body 21 that connects the inlet 21a and the outlet 21b and constitutes an injection passage 20c that is a part of the fuel supply passage, and a mounting bracket 70 for mounting a fuel cap 60 from the inside to the outside of the neck body 21 so as to be able to be opened and closed. The filler neck 20 and the mounting bracket 70 may be formed integrally, or may be a capless type that includes a valve mechanism that does not use the fuel cap 60.

[0035] The neck body 21 is an injection molded product made of conductive resin such as polyethylene with added carbon, and is provided at its lower part with a pipe connection part 22 for the filler pipe 40 and a pipe connection part 23 for the breather pipe 50. The pipe connection part 22 has an outlet port 21b and is a site for connecting the filler pipe 40, and is provided with a filler pipe removal prevention part 22a having a plurality of annular protrusions that expand the pipe connection end 41 of the filler pipe 40 to prevent it from being removed.

[0036] The pipe connection portion 23 is formed on the side of the neck body 21 and is a portion for connecting the breather pipe 50. The pipe connection portion 23 is formed with a pipe removal prevention projection 26 having a plurality of annular protrusions that expand the pipe connection end 51 of the breather pipe 50 to prevent it from coming loose.

[0037] (3) Pipe connection 23 3 is a half cross-sectional view showing the connection point between the pipe connection part 23 and the breather pipe 50, and is an enlarged view of the inside of the ellipse frame in FIG. 2. The pipe connection part 23 includes a cylindrical base part 24 forming a passage, a cylindrical pipe connection main body part 25 forming a passage from the base part 24 to the inner circumference, a pipe slip-out prevention protrusion 26 protruding in an annular shape from the outer circumference part of the pipe connection main body part 25, and an earth connection part 31. The pipe slip-out prevention protrusion 26 includes first to fourth annular protrusions 26a, 26b, 26c, and 26d in order from the tip side. The first annular protrusion 26a is located at the tip of the pipe connection main body part 25, and has a mountain shape that gradually expands in diameter from the tip and contracts in the inner circumference direction at a substantially right angle to the pipe connection main body part 25, so that the breather pipe 50 is easy to insert and difficult to come off even if a force is applied in the direction in which the breather pipe 50 is pulled out. The second annular protrusion 26b is located closer to the base than the first annular protrusion 26a, and is formed at a position away from the first annular protrusion 26a so as to be able to accommodate the O-ring 27 between the second annular protrusion 26b and the first annular protrusion 26a. The third annular protrusion 26c and the fourth annular protrusion 26d are formed closer to the base than the second annular protrusion 26b, and have substantially the same shape as the first annular protrusion 26a.

[0038] The pipe connection part 23 has an earth connection part 31 formed at one end of the base part 24. The earth connection part 31 is a part that constitutes an earth path by clamping the pipe connection end 51 of the breather pipe 50 between the outer circumferential surface 29 of the pipe connection main body 25. The earth connection part 31 is formed so that its cross section in the insertion direction of the breather pipe 50 protrudes outward from the outer circumferential surface 29 of the base part 24 and toward the pipe connection main body 25 side in a substantially L-shaped shape, and a part separated by an insertion gap from the outer circumferential surface 29 of the pipe connection main body 25 serves as a pressing part 32. The tip part of the pressing part 32 is chamfered so that the breather pipe 50 can be easily inserted between the pressing part 32 and the pipe connection main body 25.

[0039] The distance (spacing) h2 between the lower surface of the pressing portion 32 and the outer circumferential surface 29 of the pipe connection body 25 is greater than the wall thickness t1 of the breather pipe 50, that is, h2>t1.

[0040] Furthermore, the pipe connection part 23 has an anti-rotation protrusion 33 (FIG. 4) for preventing the breather pipe 50 from rotating relative to the pipe connection part 23, formed in a location where there is no earth connection part 31. The anti-rotation protrusion 33 has a height approximately the same as the wall thickness t1 of the breather pipe 50, and its tip is formed in a wedge shape so as to bite into the end face of the breather pipe 50 and prevent the breather pipe 50 from rotating. Note that the anti-rotation protrusion 33 does not necessarily have to be formed.

[0041] Furthermore, on the outer peripheral surface 29 of the pipe connection main body 25, in a cross section perpendicular to the insertion direction of the breather pipe 50, a protrusion 28 that presses the breather pipe 50 from the inside is formed in the vicinity of the closest part 29a other than the closest part 29a to the pressing part 32 of the earth connection part 31. The closest part 29a, the pressing part 32 and the protrusion 28 will be described below with respect to the first and second embodiments.

[0042] (4) Pressing portion 32 and protrusion 28 (first embodiment) FIG. 4 is an oblique view showing the vicinity of the earth connection portion 31 of the pipe connection portion 23 in the first embodiment, and FIG. 5 is a cross-sectional view perpendicular to the insertion direction of the vicinity of the earth connection portion 31 of the pipe connection portion 23 in FIG.

[0043] 5, in a cross section perpendicular to the insertion direction of the breather pipe 50, the pressing part 32 is a trapezoid having a short side L on the conductive layer 52 side of the breather pipe 50. The closest part 29a is on the outer circumferential surface 29 of the pipe connection main body 25 and is the part closest to the pressing part 32.

[0044] The protrusion 28 is on the outer peripheral surface 29 of the pipe connection main body 25, passes through the closest part 29a, and is parallel to the short side of the trapezoidal pressing part 32 and has a width L' longer than the short side in a direction away from the closest part 29a, and is formed so as to bulge from the outer peripheral surface 29. That is, the protrusion 28 is formed in the vicinity of the closest part 29a other than the closest part 29a. Also, as shown in FIGS. 4 and 5, the protrusion 28 is formed as a plane having a width L' and a depth D. Note that the tip side of the protrusion 28 of the pipe connection main body 25 is chamfered so that the breather pipe 50 can be easily inserted between the pressing part 32 and the protrusion 28.

[0045] When the breather pipe 50 is inserted into the pipe connection main body 25, the protrusion 28 of the pipe connection main body 25 presses and deforms the breather pipe 50 from the inside. However, since the breather pipe 50 has a high hardness (for example, Shore A hardness of about 60 to 70), the breather pipe 50 bulges and deforms toward the pressing part 32 side of the ground connection part 31 so that a gap S where the closest part 29a is the highest is formed.

[0046] As a result, first, even if the distance (interval) h2 between the lower surface of the pressing part 32 and the pipe connection main body 25 is longer than the wall thickness t1 of the breather pipe 50, the pressing part 32 can be in contact with the conductive layer 52 of the breather pipe 50 at least in a line or a surface.

[0047] Second, since the protrusion 28 is parallel to the short side of the trapezoidal pressing part 32 and has a width L' longer than the short side and is formed as a plane having a depth D, the breather pipe 50 also bulges outward and deforms at a position away from the closest part 29a to the pressing part 32 by the protrusion 28, and a gap S is formed, so that it contacts the entire short side of the trapezoidal pressing part 32 or the entire short side and the outer slope thereof.

[0048] However, if h2 is too long, the conductive layer 52 of the breather pipe 50 cannot contact the pressing part 32. Therefore, if the height on the closest part 29a of the gap S is hs, it is set in a range that satisfies t1 < h2 ≤ t1 + hs.

[0049] As a result, the pressing portion 32 of the earth connection portion 31 and the outer conductive layer 52 of the breather pipe 50 can be brought into contact with each other, and an earth path can be formed and secured from the pipe connection portion 23 to the breather pipe 50, and at the same time, the breather pipe 50 can be easily inserted into the pipe connection portion 23.

[0050] (5) Pressing portion 32 and protrusion 28 (second embodiment) FIG. 6 is a perspective view showing the vicinity of the earth connection portion 31 of the pipe connection portion 23 according to the second embodiment, and FIG. 7 is a cross-sectional view taken at a right angle to the insertion direction of the vicinity of the earth connection portion of the pipe connection portion 23 of FIG.

[0051] As shown in FIG. 7, in a cross section perpendicular to the insertion direction of the breather pipe 50, the pressing portion 32 has an arc shape that protrudes downward of a rectangle, i.e., toward the conductive layer 52 side of the breather pipe 50, and the protrusion 28 is formed on the outer peripheral surface 29 of the pressing portion 32 and the pipe connection main body 25, near the closest portion 29a to the pressing portion 32, and protrudes in an arc shape at a position symmetrical to the closest portion 29a.

[0052] The pressing portion 32 and the protrusions 28 are formed in a mountain-like shape in the insertion direction of the breather pipe 50. The pipe connection body 25 side of the protrusions 28 is chamfered so that the breather pipe 50 can be easily inserted between the pressing portion 32 and the protrusions 28.

[0053] When the breather pipe 50 is inserted into the pipe connection main body 25, the protrusions 28 of the pipe connection main body 25 press the breather pipe 50 from the inside, deforming the breather pipe 50. However, since the breather pipe 50 has a high hardness, the breather pipe 50 has a gap S on the closest part 29a, and the gap S curves toward the closest part 29a and deforms by bulging toward the pressing part 32 of the earth connection part 31 so as to be formed approximately symmetrically on both sides of the closest part 29a.

[0054] At this time, since the pressing portion 32 has an arc shape protruding downward from the square, that is, toward the conductive layer 52 of the breather pipe 50, the contact area between the conductive layer 52 of the breather pipe 50 and the arc-shaped lower surface of the pressing portion 32 increases.

[0055] As a result, even if the distance (interval) h2 between the lower surface of the pressing portion 32 and the pipe connection main body portion 25 is longer than the wall thickness t1 of the breather pipe 50, the pressing portion 32 can contact at least the conductive layer 52 of the breather pipe 50 in a line or a surface.

[0056] Similar to the first embodiment, if h2 is too long, the conductive layer 52 of the breather pipe 50 cannot contact the arc-shaped lower surface of the pressing portion 32. Therefore, when the height on the closest part 29a of the gap S is hs, it is set within the range that satisfies t1 < h2 ≤ t1 + hs.

[0057] As a result, the pressing portion 32 of the ground connection portion 31 can be brought into contact with the conductive layer 52 of the outer layer of the breather pipe 50, an earth path can be configured and secured from the pipe connection portion 23 to the breather pipe 50, and at the same time, the breather pipe 50 can be easily inserted into the pipe connection portion 23.

[0058] In the second embodiment, the position where the arc-shaped ridge 28 is formed is at least a position where a gap S is formed on the closest part 29a and the conductive layer 52 of the outer layer of the breather pipe 50 contacts when the breather pipe 50 bulges outward along the shape of the ridge 28.

[0059] In practicing the present invention, it is not limited to the above embodiments, and various modifications are possible without departing from the object of the present invention.

Explanation of Reference Numerals

[0060] 20 Filler neck 21 Neck main body portion 23 Pipe connection portion 24 Base 25 Pipe connection main body portion 26 Pipe retaining protrusion 28 protrusion 29 Outer surface 29a Nearest part 31 Earth connection 32 Pressing section 40 Filler pipe 50 Breather pipe 51 Pipe connection end 52 Conductive layer S Gap

Claims

1. A pipe connection structure in which a pipe having a conductive layer on an outer layer of which conductivity is imparted is connected to a pipe connection part made of a conductive resin used in a fuel pipe of a vehicle such as an automobile, and an earth path is formed from the pipe connection part to the pipe, The pipe connection portion has a hollow base portion and a hollow pipe connection body into which the pipe connection end of the pipe communicating with the tip side of the base portion can be inserted up to a base located at a predetermined length; The pipe connection body has an outer circumferential surface formed with a ring-shaped pipe retaining projection having an outer diameter larger than an inner diameter of the pipe, The base portion is provided with an earth connection portion that protrudes outward from an outer circumferential surface of the base portion toward the pipe connection body portion and has a substantially L-shaped cross section in the insertion direction of the pipe, and has a pressing portion that presses the conductive layer of the pipe from the outside of the pipe, a pipe connection structure characterized in that a protrusion for pressing the pipe from the inside is formed on the outer peripheral surface of the pipe connection body in a section perpendicular to the insertion direction of the pipe, other than the closest portion to the pressing portion, but in the vicinity of the closest portion.

2. a cross section of the pressing portion in a direction perpendicular to the insertion direction of the pipe is substantially trapezoidal, the cross section having a short side on the conductive layer side of the pipe; 2. The pipe connection structure according to claim 1, wherein a cross section of the protrusion in a direction perpendicular to the pipe insertion direction is formed from an outer circumferential surface of the pipe connection body so as to be substantially parallel to the short side and longer than the short side.

3. a cross section of the pressing portion in a direction perpendicular to the insertion direction of the pipe is substantially rectangular with an arc shape protruding toward the conductive layer of the pipe; 2. The pipe connection structure according to claim 1, wherein a cross section of the protrusion perpendicular to the pipe insertion direction has an arc shape protruding from an outer circumferential surface of the pipe connection body.

4. 4. The pipe connection structure according to claim 3, wherein the protrusions are formed at positions approximately symmetrical with respect to the portion closest to the pressing portion.

5. 5. The pipe connection structure according to claim 1, wherein a distance between the pressing portion of the earth connection portion and the closest portion of the pipe connection body is longer than a wall thickness of the pipe.

Images