JP7149039B2 - Vehicle fuel tank backflow prevention device and its mounting mechanism - Google Patents

Description

The present invention provides a backflow preventive device and a backflow preventive device which are arranged between a fuel filler opening of a vehicle such as an automobile and a fuel tank or near the entrance of the fuel tank to prevent the fuel inside the fuel tank from flowing back in the direction of the fuel filler opening. related to the mounting mechanism of

As a check valve of this type, as shown in FIG. 8, a check valve 100 is composed of three parts: a valve body 200, a valve case 300 and a spring 230. As shown in FIG. The valve body 200 includes a rod-shaped support shaft 210, a plate-shaped valve plate 220 in the shape of a circle notched in a straight line (a semicylindrical shape) and having an outer periphery composed of an arc-shaped portion 221 and a linear portion 222, and an axial center. It is composed of a spring 230 in which two winding portions 231 arranged in the same manner are connected via a connecting portion 233 and both winding end portions 232 are extended. The support shaft 210 is mounted parallel to the surface of the valve plate 220 at a predetermined distance. The spring 230 is attached so that the two wound portions 231 are externally inserted on both ends of the support shaft 210 , the connecting portion 233 contacts the valve plate 220 , and the winding end portion 232 engages with the valve case 300 .

The valve body 200 is rotatable about the support shaft 210 and is always urged by the spring 230 in the direction of abutment against the valve seat 315 of the valve case 300, so that the fuel supplied from the filler port is fuel. When flowing toward the tank, the pressure of the fluid pushes against the force of the spring 230 against the valve plate 220, opening the flow path and allowing fuel to flow from the filler neck toward the fuel tank. Further, when the refueling ends, the valve case 300 naturally abuts against the valve seat 315 and closes.

JP-A-2001-158243

By the way, the method of assembling the backflow prevention device of Patent Document 1 can be considered as follows, considering the detailed description of the invention and the drawings. First, the two wound portions 231 of the spring 230 are pushed apart and inserted from both ends of the support shaft 210 of the valve body 200 . After insertion, the two turns 231 of the spring 230 are located outside the two plate arms 211 of the valve plate 220 .

Next, the connecting portion 233 of the spring 230 is brought into contact with a predetermined position below the plate-like arm 211 of the valve plate 220 . Finally, the support shaft 210 of the valve body 200 is fitted into the bearing portion 314 of the valve case 300 so that the winding end portion 232 of the spring 230 engages with the vicinity of the valve seat 315 of the valve case 300 .

Therefore, in the method of assembling the backflow prevention device of Patent Document 1, the spring 230 is reliably inserted and fixed to the valve plate 220, and the winding end 232 of the spring 230 is engaged with the vicinity of the valve seat 315 of the valve case 300. There are many checkpoints, such as the fitting angle of the valve plate 220 when fitting the valve plate 220 into the valve case 300, and there are problems with workability and reliability.

On the other hand, one automobile consists of 20,000 to 30,000 parts and weighs as much as a ton. Regarding cost reduction, including weight reduction and simplification of assembly of each part, the effect of each part alone is not large, but the sum of them produces a very large effect, so in solving the problem, It is necessary to consider cost reduction including weight reduction and simplification of assembly.

In order to solve the above problems, the present invention of claim 1 is a backflow prevention device made of resin, which is composed of a cylindrical portion through which fuel can pass and a valve body that can be opened and closed, wherein the cylindrical portion is , a bearing provided corresponding to the rotating shaft of the valve body, a valve seat with which the valve body contacts and separates, and an inner wall of the cylindrical part, which protrudes from the upstream side of the bearing and extends in the downstream direction. The valve body has a valve body opening/closing arm, and the valve body includes a rotating shaft, a valve plate integrated with the rotating shaft, and the valve body protruding from the upstream side of the valve plate and/or the rotating shaft, and is contacted by the valve body opening/closing arm of the cylindrical portion. A backflow prevention device for a fuel tank of a vehicle, comprising: a valve body opening/closing arm guide portion that contacts the valve body opening/closing arm and exerts a force in a direction to close the valve body.

In the present invention of claim 1, since it has the above-mentioned structure, as fuel is supplied, a force is applied to the valve plate of the valve body on the downstream side by the fuel, and the valve body opening/closing arm of the tubular portion moves the valve. The valve body is opened by being displaced in the direction in which it is expanded by the valve body opening/closing arm guide portion, so that fuel can be supplied to the fuel tank. On the other hand, since a force is applied to the valve body opening/closing arm of the cylindrical portion in the direction of closing the valve body by the valve body opening/closing arm guide portion, the opening degree of the valve body can be adjusted according to the fuel supply amount. becomes possible. When the supply of fuel is finished, the valve plate of the valve body loses the downstream force of the fuel, so that the valve body opening/closing arm of the cylindrical portion is displaced toward its original position, and finally the valve body is displaced. contacts the valve seat and closes. Therefore, it is possible to provide a backflow prevention device with a simple structure.

Moreover, in the present invention, since the valve body and the cylindrical portion can be constructed by two parts, the spring is not required and the number of parts can be reduced. In addition, since assembly is completed only by mounting the rotary shaft of the valve body to the bearing portion of the tubular portion, the number of assembly man-hours is also reduced. In addition, since the number of checkpoints during assembly is reduced, the reliability of assembly is improved. Furthermore, cost reduction can be achieved.

According to the second aspect of the present invention, a claw portion is formed on the outer periphery of the cylindrical portion downstream of the position of the valve body opening and closing arm and upstream of the position of the valve seat. It is a preventive device. In the second aspect of the present invention, since the claw portion is formed on the outer circumference of the cylindrical portion, the backflow prevention device can be attached to a pipe or the like between the filler port of the fuel tank and the fuel tank. , the backflow prevention device can be prevented from coming off from a pipe or the like.

When fuel is supplied, the fuel hits the valve body, and a force is applied to the entire backflow prevention device on the downstream side, the valve body opening/closing arm of the cylindrical portion is expanded by the valve body opening/closing arm guide portion. Along with the displacement, a force that pushes the cylindrical portion outward is generated at the root portion of the valve body opening/closing arm. Since the claw portion is formed downstream from the position of the valve body opening/closing arm and upstream from the position of the valve seat, the claw portion of the cylindrical portion also generates an outward pushing force, and the fuel is supplied. It is possible to prevent the backflow prevention device from coming off from the pipe or the like even when a force directed toward the downstream side is sometimes generated in the valve body.

According to a third aspect of the present invention, there is provided a backflow prevention device for a fuel tank of a vehicle, in which projections are formed on the inner wall of the tubular portion on the downstream side of the bearing portion and/or on the downstream side of the valve body. In the third aspect of the present invention, the inner wall of the cylindrical portion downstream of the bearing portion and/or the valve body are provided with projections, so that the flow rate of the fuel suddenly increases, Therefore, even if a large force is applied to the valve body, the protrusion formed on the downstream side of the valve body will contact the inner wall of the cylindrical part, or the valve body will contact the bearing of the cylindrical part. or the projection formed on the downstream side of the valve body and the projection formed on the inner wall on the downstream side of the bearing contact the valve body It is possible to prevent the valve body from opening too much and preventing the valve body from returning to its original position when the valve body opening/closing arm climbs over the valve body opening/closing arm guide portion of the valve body. Therefore, the reliability of the backflow prevention device is improved.

The present invention according to claim 4 is made of metal or resin, and has a collar provided with an outwardly expanding flange at the upstream tip and an inwardly bent joint at the downstream tip, This backflow prevention device for a fuel tank of a vehicle is integrated with the collar by inserting the claw portion of the cylindrical portion into the interior of the coupling portion on the upstream side of the coupling portion of the collar.

In the present invention of claim 4, the collar is made of metal or resin, and has a collar provided with an outwardly expanding flange at the upstream tip and an inwardly bent joint at the downstream tip, By inserting the claw portion of the cylindrical portion into the interior of the upstream side of the connecting portion of the collar, the device is integrated with the collar. becomes possible.

According to the fifth aspect of the present invention, fuel can pass through the interior, and a resin-made backflow prevention device composed of a cylindrical portion having a claw portion on the outer wall, a valve body that can be opened and closed, and an upstream tip portion consists of an outwardly expanding collar, an inwardly directed joint at the downstream end, and a cylindrical collar made of metal or resin having a protrusion on the outer periphery between the collar and the joint. By inserting the claw portion of the backflow prevention device into the connecting portion of the collar, the backflow prevention device and the collar are integrated, and the backflow prevention device is positioned downstream and inserted into the lower pipe of the resin fuel tank. A mounting mechanism for a backflow prevention device for a fuel tank of a vehicle characterized by:

In the fifth aspect of the present invention, the mounting mechanism integrates the backflow prevention device and the collar, holds the upstream side of the collar, and allows the backflow to flow into hard-to-reach places such as the inside of the lower pipe of the fuel tank or the vicinity of the inlet of the fuel tank. Preventive devices can be fitted.

A simple structure is achieved by combining a valve body opening/closing arm formed on the cylindrical portion and a valve body opening/closing arm guide portion that exerts a force on the valve body opening/closing arm formed on the valve body in a direction to close the valve body. It is possible to provide a backflow prevention device that can adjust the opening of the valve body according to the amount of fuel supply, has a reduced number of parts, is easy to assemble, has high reliability, and is low in cost. In addition, by combining with a collar, it is possible to insert the device into the lower pipe of a resin fuel tank and install the backflow prevention device in the lower pipe or in the vicinity of the entrance of the fuel tank.

FIG. 1, which shows the first embodiment of the present invention, is a perspective view of the cylindrical portion of the backflow prevention device as viewed from the upstream side. FIG. 1, which shows the first embodiment of the present invention, is a perspective view of the tubular portion of the backflow prevention device as viewed from the downstream side. 1 shows a first embodiment of the present invention, in which (a) is a plan view of the valve body of the backflow prevention device as viewed from the upstream side, and (b) is a side view. 1 is a schematic cross-sectional view of the first embodiment of the present invention, which is a backflow prevention device in which a valve body is attached to a cylindrical portion, and in which the valve body is closed. FIG. 1 is a cross-sectional schematic diagram showing a first embodiment of the present invention, which is a backflow prevention device in which a valve body is attached to a tubular portion, and in which the valve body is open. FIG. The second embodiment of the present invention relates to integrating the backflow prevention device and the collar, (a) is a perspective view of the collar as seen from the downstream side, and (b) is the backflow prevention device and the collar. It is a cross-sectional schematic diagram when the are integrated. FIG. 10, which shows a third embodiment of the present invention, is a schematic cross-sectional view of a case in which a backflow prevention device and a collar are integrated and attached to a lower pipe of a resin-made fuel tank. FIG. 3 is an exploded perspective view of a conventional backflow prevention device;

1 to 5 show a first embodiment of the invention. The backflow prevention device 1 is composed of two members, a valve body 2 made of resin and a cylindrical portion 3 made of resin. The resin is not particularly limited as long as it has corrosion resistance to fuel, but in consideration of ease of molding, thermoplastic resin is preferable. Polyacetal, which is excellent in strength, is more preferable.

First, the valve body 2 will be explained below. As shown in FIG. 3(a), the valve body 2 has a rod-like rotary shaft 21 at a position displaced from the center line X of the circle, and an arcuate portion 22 on the outer circumference of the circle cut in a straight line. A plate-like valve plate 24 including a portion 23 is integrally molded. The shape of the arc-shaped portion 22 of the valve plate 24 may be formed so as to match the shape of the valve seat 34 provided on the cylindrical portion 3, which will be described later. 3, in order to conform to the shape of the valve seat 34 formed on the cylindrical portion 3 of FIGS. A protruding arcuate portion 25 corresponding to the outer diameter of the cylindrical portion 3 is formed so as to protrude outward from the arcuate portion 22 .

As shown in FIGS. 3, 4 and 5, on the upstream side of the valve body 2 is a valve body opening/closing arm guide portion 26 which is on the center line Y of the circle and protrudes from the rotating shaft 21 and the valve plate 24. formed. The side of the valve body opening/closing arm guide portion 26 with which the valve body opening/closing arm 32 of the tubular portion 3 (to be described later) abuts protrudes from the rotating shaft 21 in a convex arc shape. Here, the protrusion height of the valve body opening/closing arm guide portion 26 is the height of the valve body opening/closing arm 32 moved when the valve body opening/closing arm 32 is displaced most, that is, when the valve body 2 is opened most. It is designed so that the contact portion with the arm guide portion 26 does not climb over the valve body opening/closing arm guide portion 26 .

The shape of the side of the valve body opening/closing arm guide portion 26 protruding from the rotation shaft 21 with which the valve body opening/closing arm 32 abuts is such that the valve body opening/closing arm 32 of the cylindrical portion 3 contacts the valve body opening/closing arm guide portion 26 . As long as the arm 32 contacts the valve body opening/closing arm 32 in a direction to close the valve body 2 and the valve body 2 can be smoothly opened and closed according to the amount of fuel supplied, the arc shape is not limited to the above.

3, 4 and 5, the side of the valve body opening/closing arm guide portion 26 on which the valve body opening/closing arm 32 does not come into contact is gently inclined toward the valve plate 24, and the end portion thereof is almost the same as the valve plate 24. are at the same height. The shape is not limited, and may be substantially perpendicular to the valve plate 24 as long as ease of molding is taken into consideration.

Furthermore, in the present embodiment, the position where the valve body opening/closing arm guide portion 26 is formed protrudes from the rotating shaft 21. It may be formed in consideration of the shape and degree of displacement of the valve body opening/closing arm 32, the strength of the valve body opening/closing arm 32, and the like. good too.

The width of the valve body opening/closing arm guide portion 26 in FIG. When the valve body opening/closing arm 32 moves in contact with the valve body opening/closing arm guide portion 26, the valve body opening/closing arm guide portion 26 is not twisted and displaced. It must have a width that can be displaced along the center line Y direction.

As shown in FIG. 3(b), on the downstream side of the valve plate 24, projections 27 are formed at positions that contact two projections 33 (FIG. 2) formed on the tubular portion 3, which will be described later. It is When the flow rate of fuel suddenly increases and a large force is generated against the valve plate 24 due to the force of the sudden increase, the projection 27 abuts against the projection 33 of the cylindrical portion 3 , This is to prevent the valve body opening/closing arm 32 of the tubular portion 3 from over-opening and to prevent the valve body 2 from returning to its original position when the valve body opening/closing arm 32 climbs over the valve body opening/closing arm guide portion 26 of the valve body 2 . .

In addition, when the protrusion 33 of the tubular portion 3 is brought into contact with the valve plate 24 to achieve the above purpose, the protrusion 27 is not necessary.

Further, the strength of the valve body opening/closing arm 32 is sufficient, and even if the flow rate of fuel suddenly increases and a large force is generated on the valve plate 24 due to the momentum of the fuel flow rate, the valve body opening/closing arm 32 will not The protrusion 27 is not necessary if there is no concern that the valve body 2 will not return to its original position by going over the valve body opening/closing arm guide portion 26 .

On the other hand, in FIG. 3(b), the same shape as the valve body opening/closing arm guide part 26 is formed on the downstream side of the valve body 2, and the same shape as the protrusion 27 is formed on the upstream side of the valve body 2 so that the shape is vertically symmetrical. , there is no need to confirm the vertical direction of the valve body 2 when the valve body 2 is assembled to the tubular portion 3, so that the assembly efficiency is improved.

Next, the tubular portion 3 will be described below. As shown in FIGS. 1, 2, 4 and 5, the tubular portion 3 has a bearing portion 31 for mounting the rotary shaft 21 of the valve body 2 therein, protrudes from the upstream side of the bearing portion 31, and extends downstream. A valve body opening/closing arm 32 extending in a direction, a protrusion 33 downstream of the bearing 31, and a valve seat 34 with which the arcuate portion 22 of the valve body 2 contacts and separates are formed. A claw portion 35 is formed on the outer periphery of the cylindrical portion 3, downstream of the position where the internal valve body opening/closing arm 32 protrudes, and upstream of the position where the valve seat 34 is formed. ing.

The valve body opening/closing arm 32 protrudes in the width direction parallel to the center line X of the circle in FIG. 3(a), and as shown in FIG. After protruding, it has a convex circular portion and extends toward the downstream side and toward the center of the tubular portion 3 . The tip portion is further bent toward the center of the cylindrical portion 3 , and the front portion of the bent shape abuts the valve body opening/closing arm guide portion 26 of the valve body 2 . Here, the bent portion allows the valve body opening/closing arm 32 to move smoothly while being in contact with the valve body opening/closing arm guide portion 26 of the valve body 2, thereby allowing the valve body 2 to open and close.

The valve body opening/closing arm 32 may have a shape in which straight lines are connected. Furthermore, the bent shape of the tip portion may be omitted. If there is no bent shape at the tip, the valve body opening/closing arm 32 abuts on the valve body opening/closing arm guide portion 26 of the valve body 2, moves smoothly, and the valve body 2 opens and closes. It is desirable that the tip of the arm 32 be chamfered.

The valve seat 34 is formed by notching a portion of the valve plate 24 formed on the inner wall of the tubular portion 3 with which the arcuate portion 22 abuts and the downstream side of the tubular portion 3 , so that the protruding arcuate portion 25 of the valve plate 24 is cut out. It is composed of a part that abuts. The valve plate 24 is provided with the protruding arcuate portion 25, the downstream side of the tubular portion 3 is notched, and the portion of the valve plate 24 with which the protruding arcuate portion 25 abuts is formed, particularly because the backflow prevention device 1 is used for fuel. When the valve body 2 is installed in the tank 5 and the space on the downstream side of the backflow prevention device 1 becomes large when the valve body 2 is opened, fuel is supplied through the projecting arcuate portion 25 of the opened valve plate 24. This is because the flow path is changed, and fuel can be supplied with a small opening of the valve body 2 . Of course, if the space on the downstream side of the backflow prevention device 1 does not become large when the valve body 2 is opened, the protruding arcuate portion 25 is unnecessary in the valve body 2, and the notch on the downstream side of the cylindrical portion 3 The valve seat 34 may be circumferentially formed on the inner wall of the cylindrical portion 3.

In addition, when the projection 27 of the valve plate 24 is brought into contact with the cylindrical portion 3 to achieve the above purpose, the projection 33 is unnecessary.

Projections 33 are formed at two locations on the downstream side of the bearing portion 31 of the tubular portion 3 . The protrusion 33 prevents the valve body 2 from opening too much when the flow rate of fuel suddenly increases and the momentum of the sudden increase causes a large force to be applied to the valve plate 24 . This is to prevent the problem that the valve body 2 cannot return to its original position by getting over the valve body opening/closing arm guide portion 26 of the body 2 .

Furthermore, as with the projection 27 of the valve body 2 described above, the strength of the valve body opening/closing arm 32 is sufficient, and the flow rate of fuel suddenly increases, and the momentum of the sudden increase generates a large force against the valve plate 24. Even in such a case, the protrusion 33 is unnecessary if there is no concern that the valve body opening/closing arm 32 will climb over the valve body opening/closing arm guide portion 26 of the valve body 2 and the valve body 2 will not return to its original position. .

The claw portion 35 has a substantially triangular cross-sectional shape with a thick wall on the downstream side. The tubular portion 3 at the portion where the claw portion 35 is formed is divided into three parts, and the valve body opening/closing arm 32 is formed inside one of the parts. The division of the tubular portion 3 on which the claw portions 35 are formed is such that when the tubular portion 3 is inserted into a pipe or the like later, the tubular portion 3 on which the claw portions 35 are formed is displaced inward. This is to facilitate insertion.

Next, with reference to FIGS. 4 and 5, the attachment of the valve body 2 to the tubular portion 3 and the movement of the valve body opening/closing arm 32 and the valve body opening/closing arm guide portion 26 in the present invention will be described. When the valve body 2 shown in FIG. 3 is attached to the cylindrical portion 3 shown in FIGS. 1 and 2, the valve body 2 is slightly opened and the valve body opening/closing arm guide portion 26 guides the valve body 2 into a cylindrical shape. The valve body opening/closing arm 32 of the portion 3 is floated, and the rotating shaft 21 of the valve body 2 is attached to the bearing portion 31 of the cylindrical portion 3 . By slightly floating the valve body opening/closing arm 32 of the tubular part 3, a force is generated in the valve body opening/closing arm 32 of the tubular part 3 in a direction to return to its original shape. As shown in FIG. 4, the upstream side of the protruding arcuate portion 25 of the valve body 2 abuts against the valve seat 34 of the cylindrical portion 3 or is fixed at a position with a slight gap.

Even if the valve body 2 is fixed at a position with a slight gap, the pressure in the fuel tank increases after the fuel is supplied, and force is applied to the valve body 2 from the downstream side. 3 comes into contact with the valve seat 34 . Here, in FIG. 4 and subsequent figures, the symbol “+” indicates the center of rotation of the rotating shaft 21 of the valve body 2 .

When fuel is supplied, as shown in FIG. 5, the valve body 2 opens due to the flow and weight of the fuel. The contact portion of 26 moves above the valve body opening/closing arm guide portion 26 . At this time, since a force acts on the valve body opening/closing arm 32 in a direction to close the valve body 2, the opening degree of the valve body 2 is adjusted while balancing the fuel flow and weight.

Further, when the fuel reaches the maximum flow rate or exceeds the planned maximum flow rate, the protrusion 27 of the valve body 2 and the protrusion 33 of the tubular portion 3 come into contact with each other. As a result, further opening of the valve body 2 can be prevented, and the problem that the valve body opening/closing arm 32 climbs over the valve body opening/closing arm guide portion 26 of the valve body 2 and the valve body 2 cannot return to its original position can be prevented. can be prevented.

When the supply of fuel is completed, no force is generated by the fuel on the upstream side of the valve body 2, so the valve body opening/closing arm 32 of the tubular portion 3 returns to its original position shown in FIG. 4, and the valve body 2 is closed. , it is possible to prevent the fuel in the fuel tank from flowing back in the direction of the filler port.

FIG. 6 shows a second embodiment of the present invention, in which the backflow prevention device 1 shown in FIGS. 1 to 4 is attached to the collar 4 and integrated. The collar 4 is made of metal, specifically stainless steel, and as shown in FIG. 6(a), has an outwardly widening flange 41 formed at its upstream end. In addition, a connecting portion 42 bent inward is formed at the downstream end portion. The connecting portion 42 is divided into two regions with different diameters. It is a claw portion connecting portion 44 that is connected to the claw portion 35 of the cylindrical portion 3 . Further, a protrusion 45 is formed in the vicinity of the joint portion 42 which is the outer peripheral portion between the flange portion 41 and the joint portion 42 . Incidentally, the collar 4 may be molded with resin. The resin is not particularly limited as long as it has corrosion resistance to fuel and mechanical strength for fastening with pipes and hoses later.

After the backflow prevention device 1 assembled as shown in FIGS. Then, the claw portion 35 of the cylindrical portion 3 contacts the inner surface of the claw portion connecting portion 44, and the backflow prevention device 1 and the collar 4 are integrated. As a result, by holding the upstream side of the collar 4, especially the collar portion 41, and placing the backflow prevention device 1 on the downstream side, backflow prevention can be performed in a hard-to-reach place such as the lower pipe of the fuel tank or the vicinity of the entrance of the fuel tank. It is possible to wear the device.

FIG. 7 shows a third embodiment of the present invention, in which the backflow prevention device 1 and the collar 4 shown in FIGS. It shows the case of mounting inside. The resin fuel tank 5 is manufactured by blow molding using, for example, high-density polyethylene resin. In this embodiment, the lower pipe 6 is also molded at the same time. The resin fuel tank 5 is a multi-layered fuel tank that uses a fuel permeation barrier portion 52 between resin body layers 51 made of high-density polyethylene resin in order to comply with hydrocarbon emission standards. For example, nylon or EVOH (ethylene-vinyl alcohol copolymer) is used for the fuel permeation barrier portion 52 .

First, the backflow prevention device 1 and the collar 4 shown in FIGS. Then, the upstream end of the lower pipe 6 and the flange 41 of the collar 4 are brought into contact with each other. Next, the outer side of the lower pipe 6 is covered with the filler hose 7 . Finally, the filler hose 7 is fixed to the lower pipe 6 by the hose band 8 from the outside of the filler hose 7 .

The projection 45 of the collar 4 in this embodiment is formed so as to contact the inside of the lower pipe 6 at a position where the filler hose 7 is not covered. This is for the following reasons. Due to the projection 45 of the collar 4, a force is generated from the inside to the outside of the lower pipe 6 at the contact portion between the projection 45 of the collar 4 and the lower pipe 6, and the collar 4 becomes difficult to come off to the upstream side of the lower pipe 6. there is On the other hand, since the filler hose 7 is fixed to the lower pipe 6 by the hose band 8 from the outside, force is generated on the lower pipe 6 from the outside to the inside at this portion.

The protrusion 45 provided on the outer peripheral portion of the collar 4 is formed at a position where it abuts on the inside of the lower pipe 6 not covered with the filler hose 7. , and on the upstream side, the hose band 8 generates a force from the outside to the inside through the filler hose 7. can make it difficult to remove.

1 Backflow prevention device 2 Valve body 21 Rotating shaft 22 Circular part 23 Straight part 24 Valve plate 25 Protruding arcuate part 26 Valve body opening/closing arm guide part 27 Protrusion 3 Cylindrical part 31 Bearing 32 Valve body opening/closing arm 33 Protrusion Portion 34 Valve seat 35 Claw portion 4 Collar 41 Collar portion 42 Joint portion 43 Claw insertion portion 44 Claw portion joint portion 45 Protruding portion 5 Fuel tank 51 Resin body layer 52 Fuel permeation barrier portion 6 Lower pipe 7 Filler hose 8 Hose band

Claims (5)

A resin backflow prevention device composed of a cylindrical portion through which fuel can pass and a valve body that can be opened and closed,
The cylindrical portion includes a bearing portion provided corresponding to the rotation shaft of the valve body, a valve seat with which the valve body contacts and separates, and an inner wall of the cylindrical portion, which is upstream of the bearing portion. having a valve body opening and closing arm projecting from and extending in the downstream direction,
The valve body includes a rotating shaft, a valve plate integrated with the rotating shaft, and protruding from an upstream side of the valve plate and/or the rotating shaft, and the valve body opening/closing arm of the cylindrical portion abuts against it, A backflow prevention device for a fuel tank of a vehicle, comprising a valve body opening/closing arm guide portion that exerts a force on the valve body opening/closing arm in a direction to close the valve body. 2. The vehicle fuel tank according to claim 1, wherein a pawl portion is formed on the outer wall of the cylindrical portion downstream of the position of the valve body opening and closing arm and upstream of the position of the valve seat. Backflow preventer. 3. The backflow prevention device for a fuel tank of a vehicle according to claim 1, wherein projections are formed on an inner wall of said tubular portion on a downstream side of said bearing portion and/or on a downstream side of said valve plate. . It is made of metal or resin and has a collar provided with an outwardly expanding flange at the upstream end and an inwardly bent joint at the downstream end, and upstream of the joint of the collar. 3. The backflow prevention device for a fuel tank of a vehicle according to claim 2 , wherein the claw portion of the cylindrical portion is inserted into the inner side of the tubular portion to be integrated with the collar. A resin-made backflow prevention device composed of a cylindrical portion through which fuel can pass and having claw portions on the outer wall, and a valve body that can be opened and closed;
It is made of metal or resin, having an outwardly widening flange at the upstream end, an inwardly directed joint at the downstream end, and a projection on the outer peripheral portion between the flange and the joint. consists of a tubular collar of
The backflow prevention device and the collar are integrated by inserting the claw portion of the backflow prevention device into the coupling portion of the collar. A mounting mechanism for a backflow prevention device for a fuel tank of a vehicle, characterized by being inserted and mounted.

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