JP7222774B2 - Mounting structure of backflow prevention device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for a backflow prevention device installed in an inlet, which is the entrance of a resin fuel tank of a vehicle such as an automobile, for preventing fuel in the fuel tank from flowing back in the direction of a filler opening.

This type of backflow prevention device (sometimes called a "check valve") is a cylinder that allows fuel to pass through a hole that has been opened in the fuel tank in advance or that has been opened after the fuel tank is molded. There is a case where a shaped inlet is attached and a check valve is attached to the inlet, and a case where the inlet is integrally formed in the fuel tank in advance and the check valve is attached to the inlet. As the latter technique, for example, the following two techniques are known (Patent Document 1 and Patent Document 2).

As shown in FIG. 6, the technique of Patent Document 1 is a fuel tank 100 made of a thermoplastic synthetic resin, which is composed of an upper shell portion 110 and a lower shell portion 120 which are separately molded by injection molding. An inlet portion 200 is formed integrally with the shell portion 110 . A check valve 300 is provided at the inlet on the inner surface side of the upper shell portion 110 of the inlet portion 200, and the inlet of the inlet portion 200 on the inner surface side of the upper shell portion 110 is integrally extended downward from the upper shell portion 110 for steam. It is surrounded by an outflow prevention wall 400, and the length of the steam outflow prevention wall 400 extends below the liquid surface of the fuel tank 100 when the fuel is full. The fuel tank 100 is characterized in that, when the check valve 300 is opened, the tip of the check valve 300 abuts against the vapor outflow prevention wall 400, and the opening degree of the check valve 300 is regulated.

On the other hand, according to the technique of Patent Document 2, as shown in FIG. 7, the check valve 300 includes a housing (a mounting base 311 and a housing main body 320 attached to the lower end of the mounting base 311), a valve body 321, and a spring. 500, an O-ring 600, a spacer 700, and a retainer 800 are the main components. In addition, in FIG. 7, CP described in the upper part is a connection pipe.

Regarding the operation of mounting the check valve 300 to the tank body TB, the housing is in a state in which the annular holding portion 312 and the housing body 320 are separated, and the valve body 321, the spring 500, etc. are assembled in advance to the housing body 320. to From this state, first, the O-ring 600 is stored in the storage space 313 of the annular holding portion 312 and the O-ring 600 is pressed by the spacer 700 . Subsequently, the retainer 800 is inserted into the housing portion 315 of the large diameter portion 314 so that the retainer 800 is supported by the mounting base 311 and supports the lower surface of the spacer 700 .

Further, the housing main body 320 is passed through the central hole of the retainer 800, the engaging protrusion 322 of the housing main body 320 is aligned with the insertion notch 316 of the mounting base 311, and is inserted into the mounting recess 317, and then rotated by a predetermined angle. Thus, the housing body 320 is integrally assembled with the mounting base 311 .

In such an assembled state, the check valve 300 is inserted into the valve mounting portion TBa from the outside of the tank body TB. The valve mounting portion TBa abuts on the claw portion 810 of the retainer 800 at the engaging projections TBc, TBc, and the engaging projections TBc, TBc climb over the claw portions 810, 810 and engage with the claw portions 810, 810. At the same time, the valve mounting portion TBa is inserted into the inner peripheral side of the storage space 313 . As a result, the check valve 300 is retained with respect to the tank body TB. In this state, the O-ring 600 seals between the valve mounting portion TBa and the housing of the check valve 300 .

Japanese Patent Application Laid-Open No. 2009-137488 JP-A-2002-46488

By the way, in resin fuel tanks and fuel supply paths, it is desired to suppress fuel permeation not only in the fuel tank itself, but also in general resin parts that make up the path for supplying and holding fuel and their fastening parts. ing. However, in Patent Document 1, it is stated that "the inlet part is formed integrally with the upper shell part by injection molding, and the sealing performance between the upper shell part and the inlet part is ensured". However, it is difficult to continuously form the fuel permeation prevention structure currently used in the fuel tank main body, for example, a 4-kind 6-layer structure having a barrier layer up to the inlet. Also, in Patent Document 2, "A valve attachment portion TBa is protruded in the shape of a pipe on a side portion of the tank body TB. In addition, on the side of the valve mounting portion TBa, two engaging projections TBc, TBc (tank side engaging portion) for mounting a check valve as described later are formed at 180° positions. is formed.”, and there is no particular mention of suppression of fuel permeation between the tank body TB and the valve mounting portion TBa.

On the other hand, as is clear from FIG. 7, in order to attach the check valve 300 described in Patent Document 2 to the tank body TB, it is necessary to combine many members, which is complicated and leads to an increase in cost. Also, as described above, many members are combined, but their fuel permeability is unknown.

Accordingly, the present invention provides a structure for mounting a backflow prevention device to a resin fuel tank, which improves fuel permeation suppressing performance, is not complicated in structure, is excellent in mountability, and is inexpensive.

In order to solve the above-mentioned problems, the present invention of claim 1 is a backflow prevention device mounting structure for mounting a backflow prevention device to an inlet of a resin fuel tank, wherein the inlet protrudes toward the outside of the vehicle of the resin fuel tank. The barrier layer is formed integrally with the resin fuel tank, and the barrier layer formed on the resin fuel tank to prevent fuel permeation is also continuously extended into the inlet, and is formed on the outer wall of the inlet at the outer side of the vehicle. is formed with a connection member mounting portion that protrudes so that the outer diameter increases toward the side of the resin fuel tank, and the backflow prevention device consists of a check valve that can be opened and closed and an inner has a tubular collar through which fuel can pass, a check valve is attached to a first tip that is one tip of the collar, and a check valve is attached to a second tip that is the other tip of the collar is formed with a flange projecting outward, and a bead portion having an outer diameter equal to or larger than the inner diameter of the inlet is formed on the outer wall of the collar on the side of the resin fuel tank from the collar. 1 By inserting the backflow prevention device into the inlet from the tip side, the bead portion contacts the inner wall of the inlet and the flange portion contacts the tip of the connection member mounting portion of the inlet, and the backflow prevention device is attached to the inlet. Structure.

In the first aspect of the present invention, the inlet is integrally formed with the resin fuel tank so as to protrude outwardly of the resin fuel tank, and the resin fuel tank has a barrier layer for preventing fuel permeation. Since it also extends continuously into the inlet, it is possible to suppress permeation of fuel from the connecting portion between the resin fuel tank and the inlet and from the inlet.

The barrier layer for preventing fuel permeation formed on the resin fuel tank, which is continuously extended into the inlet, is preferably extended to the tip of the inlet. It is covered by a member, and if the covering member takes measures to suppress fuel permeation, it may be extended to a portion where the covering member does not exist.

The backflow prevention device has a backflow prevention valve that can be opened and closed, and a cylindrical collar portion that allows fuel to pass through an interior with an outer diameter equal to or smaller than the inner diameter of the inlet. A non-return valve is attached to the collar, and the second tip, which is the other tip of the collar, is formed with an outwardly protruding flange. Since a bead portion having an outer diameter equal to or larger than the inner diameter of the inlet is formed, by inserting the backflow prevention device from the first tip side to the tip portion of the inlet, the bead portion comes into contact with the inner wall of the inlet to prevent backflow. The backflow prevention device can be fixed to the inlet by pressing the space between the device and the inlet, and the brim contacts the tip of the connection member mounting portion of the inlet. . Also, the backflow prevention device can be manufactured at low cost.

According to the second aspect of the present invention, the brim of the backflow prevention device is formed with a notch portion that enables the direction of the backflow prevention valve to be grasped, and the end portion of the connecting member mounting portion of the inlet on the outside of the vehicle is The mounting structure of the backflow prevention device is provided with a convex portion that can be engaged with a notch portion of the backflow prevention device.

According to the second aspect of the present invention, a notch portion is formed in the flange portion, and a convex portion that can be engaged with the notch portion of the backflow prevention device is formed in the vehicle-outside end portion of the connection member mounting portion of the inlet. Therefore, by engaging the notch formed in the flange with the projection formed in the inlet, the backflow prevention device can be installed in the resin fuel tank with the direction of the backflow prevention valve always fixed. can be inserted into In addition, as a result, it is possible to prevent variation in the direction of opening and closing of the check valve in the resin fuel tank, thereby ensuring normal operation of the check valve.

According to a third aspect of the present invention, there is provided a mounting structure for a backflow prevention device in which a first tip side of a collar portion of the backflow prevention device is obliquely notched. In the present invention of claim 3 , since the first tip portion side of the collar portion of the backflow prevention device is notched obliquely, the opening area of the collar portion becomes large, and the flow rate of fuel from the inlet portion side increases. It is also possible to deal with

The inlet is integrally formed with the resin fuel tank so as to protrude outwardly of the resin fuel tank, and a barrier layer formed on the resin fuel tank to prevent fuel permeation extends continuously into the inlet. Therefore, permeation of fuel from the connecting portion between the resin fuel tank and the inlet portion and from the inlet portion can be suppressed.

The backflow prevention device has an openable and closable backflow prevention valve, and a tubular collar portion having an outer diameter equal to or smaller than the inner diameter of the inlet, through which fuel can pass. A non-return valve is attached to the tip portion, and the second tip portion, which is the other tip portion of the collar portion, is formed with an outwardly protruding flange portion, which extends from the flange portion of the collar portion to the outer wall on the side of the resin fuel tank. Since a bead portion having an outer diameter equal to or larger than the inner diameter of the inlet is formed, the bead portion is brought into contact with the inner wall of the inlet by inserting the backflow prevention device into the tip portion of the inlet from the first tip portion side. The backflow prevention device can be fixed to the inlet by pressing between the backflow prevention device and the inlet, and the flange portion abuts on the tip of the connection member mounting portion of the inlet. is also excellent. Also, the backflow prevention device can be manufactured at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1, which shows an embodiment of the present invention, is a perspective view showing the appearance of a resin fuel tank. FIG. 1, which shows an embodiment of the present invention, is a perspective view showing the appearance of a backflow prevention device. 1, which shows an embodiment of the present invention, is a cross-sectional view of a backflow prevention device. FIG. 3 is an enlarged view of part A in FIG. 2 ; 1, which shows an embodiment of the present invention, is a schematic cross-sectional view when a backflow prevention device is attached to a fuel tank. FIG. 2 is a cross-sectional view of an inlet portion of a conventional fuel tank (Patent Document 1). FIG. 2 is an exploded cross-sectional view showing a state before a conventional check valve is assembled to a tank body (Patent Document 2).

A mounting structure of a backflow prevention device to a resin fuel tank 1 (hereinafter referred to as "fuel tank") according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. FIG. 1 is a perspective view of a fuel tank 1 according to an embodiment of the invention. The fuel tank 1 is mainly manufactured by blow molding. The tank top wall 11 and the tank bottom wall 12 of the tank outer wall are integrally formed, and the main material is high density polyethylene (HDPE). Ethylene-vinyl alcohol copolymer (EvOH) is used. The structure is composed of 4 types and 6 layers of main material/adhesive layer/barrier layer/adhesive layer/recycled material layer/main material structure. It should be noted that the fuel tank 1 may be composed of 5 layers of 3 types of main material/adhesive layer/barrier layer/adhesive layer/main material from the inside.

As shown in FIG. 1, the fuel tank 1 manufactured according to the embodiment of the present invention has a pump unit mounting hole 13 formed on the top surface thereof for inserting and removing a fuel pump (not shown) and the like. ing. An inlet 2 having a circular cross section is formed on the side or top of the fuel tank 1 to inject fuel from an inlet pipe (not shown).

In addition, an outer peripheral rib 14 is formed around the entire circumference of the fuel tank 1, and mounting holes 15 are formed at several predetermined locations such as corner portions of the outer peripheral rib 14. The fuel tank 1 is attached to the vehicle body by bolting 15 and the vehicle body. Furthermore, various hose attachment portions 16 are formed on the top surface of the fuel tank 1 to connect hoses for recovering fuel vapor inside.

FIG. 2 is an external view of the backflow prevention device 3. As shown in FIG. This figure also shows the fuel tank 1 and the inlet 2 so that the positional relationship when the backflow prevention device 3 is attached to the inlet 2 can be grasped. As shown in FIGS. 2 and 3 , the backflow prevention device 3 has a circular cross section like the inlet 2 and has a cylindrical collar portion 31 with an outer diameter slightly smaller than that of the inlet 2 . A first tip portion 32 on the side of the fuel tank 1 is obliquely notched, and the notched tip is once bent inward and then bent outward again. A check valve 33 is attached to the tip thereof via a spring 4 .

Due to the above shape, even if the check valve 33 is attached via the spring 4, the check valve 33 can be attached so as to fit within the outer diameter of the collar portion 31, and the check valve 3 can be attached to the inlet 2. can be inserted. Further, since the opening area can be increased by notching the collar portion 31 obliquely, the fuel can be reliably discharged from the gap between the open check valve 33 and the collar portion 31 even when the fuel flow rate increases. It can flow into the fuel tank 1 .

Polyacetal (POM), which has well-balanced mechanical properties, fuel resistance, and fatigue resistance, is used as the material of the collar portion 31 and the check valve 33 . Nylon may be used for the collar portion 31 and the check valve 33, or separate materials may be used. Furthermore, an ethylene-vinyl alcohol copolymer (EvOH) used as a barrier layer in the fuel tank 1 may be formed inside the collar portion 31 . In addition, at least one of the collar portion 31 and the check valve 33 may be made of metal such as stainless steel.

A second tip portion 34 of the collar portion 31 opposite to the fuel tank 1 is formed with a flange portion 35 projecting outward. A notch portion 37 is formed in the collar portion 35 by cutting out a part of the collar portion 35 . Further, on the fuel tank 1 side of the collar portion 35 , a bead portion 36 is formed in which the diameter of the outer wall of the collar portion 31 is larger than the outer diameter of the collar portion 31 and which is equal to or larger than the inner diameter of the inlet 2 .

Although the bead portion 36 may be formed along the entire circumference of the collar portion 31, the bead portion 36 is not limited to the entire circumference. , 6 points may be formed at intervals of 60°. In other words, it is sufficient that the bead portion 36 presses the inner wall of the inlet 2 to fix the collar portion 31 to the inner wall of the inlet 2 .

On the other hand, a connection member mounting portion 21 is formed on the outer wall of the tip portion of the inlet 2 so as to protrude toward the fuel tank 1 side so that the outer diameter increases. On the opposite side, a convex portion 23 that can be inserted into the notch portion 37 of the collar portion 35 of the collar portion 31 is formed.

As a result, when the backflow prevention device 3 is inserted into the inlet 2 from the first tip portion 32 side of the collar portion 31 , the bead portion 36 presses the inner wall of the inlet 2 and the collar portion 35 contacts the tip of the inlet 2 . Thereby, the backflow prevention device 3 can be inserted and fixed to the inlet 2 . In addition, the notch 37 formed in the flange 35 of the collar 31 and the protrusion 23 formed at the tip of the inlet 2 are engaged with each other to keep the backflow prevention device 3 in the direction of the backflow prevention valve 33 at all times. Since it can be inserted into the fuel tank 1 in a fixed direction, it is possible to prevent variation in the opening/closing direction of the check valve 33 in the fuel tank 1, and to ensure the normal operation of the check valve 3. can be done.

As shown in FIG. 4 , the connection member contact surface 22 of the connection member mounting portion 21 of the inlet 2 has a higher surface precision than the other outer wall surface of the inlet 2 . The high surface precision of the connection member contact surface of the connection member mounting portion of the inlet means that, for example, when the maximum height Rz regarding surface roughness is used as an index, It means a surface roughness of the order of 10 μm, which is one order of magnitude lower than the surface roughness of the order of 100 μm. In the notation of the conventional finishing symbol, it corresponds to ▽▽. The surface accuracy of the connection member contact surface 22 of the connection member attachment portion 21 of the inlet 2 in this embodiment was set to Rz12.5 or Rz25, using the maximum height Rz for surface roughness as an index. The numerical value following Rz represents the unit of length μm. As a result, a high sealing performance can be ensured between the inner surface of the connection member (the filler hose 5 in this embodiment) and the connection member contact surface 22 .

FIG. 5 is a schematic cross-sectional view when the backflow prevention device 3 shown in FIGS. 1 to 4 is attached to the fuel tank 1 integrally formed with the inlet 2. As shown in FIG.

The backflow prevention device 3 in which the collar portion 31 and the backflow prevention valve 33 are integrated via the spring 4 is positioned so that the backflow prevention valve 33 side faces the fuel tank. from the outside of the vehicle. Then, the collar portion 35 of the collar portion 31 is turned to insert the notch portion 37 of the collar portion 35 into the convex portion 23 of the inlet 2 and further pushed to assemble the backflow prevention device 3 to the inlet 2 . Next, the outer side of the inlet 2 is covered with the filler hose 5 . Finally, the filler hose 5 is fixed to the inlet 2 by the hose band 6 from the outside of the filler hose 5 .

In this embodiment, the region where the barrier layer 10 for preventing fuel permeation formed in the fuel tank 1 extends continuously to the inlet 2 extends to the tip of the inlet 2 on the outside of the vehicle, as shown in FIG. Although extended, a filler hose 5 and a hose band 6 are present on the outer diameter side of the inlet 2, as is clear from FIG. The material of the filler hose 5 is also determined in consideration of fuel permeability. Therefore, in FIG. 5, the area where the barrier layer 10 for preventing fuel permeation formed in the fuel tank 1 and which is continuously extended to the inlet 2 extends slightly outside the vehicle from the position covered by the filler hose 5 in FIG. If it is extended, fuel permeation can be suppressed.

1 resin fuel tank (fuel tank)
10 Barrier layer 2 Inlet 3 Backflow prevention device 4 Spring 5 Filler hose 6 Hose band
21 connection member mounting portion
22 connection member contact surface
23 Convex portion 31 Collar portion 32 First tip portion 33 Check valve 34 Second tip portion 35 Collar portion 36 Bead portion 37 Notch portion

Claims (3)

A backflow prevention device mounting structure for mounting the backflow prevention device to an inlet of a resin fuel tank,
The inlet is formed integrally with the resin fuel tank so as to protrude outwardly of the resin fuel tank,
A barrier layer for preventing fuel permeation formed in the resin fuel tank is continuously extended into the inlet,
A connecting member mounting portion is formed on the outer wall of the inlet at the tip of the inlet in the vehicle outer side direction so that the outer diameter increases in the resin fuel tank side direction,
The backflow prevention device is
a non-return valve that can be opened and closed;
having a tubular collar portion through which fuel can pass through an interior having an outer diameter equal to or smaller than the inner diameter of the inlet;
The non-return valve is attached to a first tip portion which is one tip portion of the collar portion,
A second tip portion, which is the other tip portion of the collar portion, is formed with a flange portion protruding outward,
A bead portion having an outer diameter equal to or larger than the inner diameter of the inlet is formed on an outer wall of the collar portion closer to the resin fuel tank than the collar portion,
By inserting the backflow prevention device into the inlet from the first distal end portion side, the bead portion abuts the inner wall of the inlet, and the flange portion abuts the distal end of the connection member mounting portion of the inlet. A mounting structure for a backflow prevention device in which the backflow prevention device is mounted on the inlet. The brim of the backflow preventive device is formed with a notch portion that allows the orientation of the backflow preventive valve to be grasped, and the backflow preventive 2. The mounting structure of a backflow prevention device according to claim 1, wherein a convex portion is formed that can be engaged with the cutout portion of the device. 3. The mounting structure of a backflow prevention device according to claim 1, wherein said first tip portion side of said collar portion of said backflow prevention device is obliquely notched.

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