JP4660156B2 - Fuel backflow prevention valve - Google Patents

Description

  The present invention relates to a fuel backflow prevention valve which is attached to a fuel tank of an automobile or the like and securely closes a fuel passage without reliably using a rubber seal member to reliably prevent backflow of fuel in the fuel tank.

  A fuel supply pipe connected to a fuel supply port is connected to the fuel tank of the automobile, and a fuel backflow prevention valve for preventing a backflow to the fuel supply pipe is connected near the outlet of the fuel supply pipe. . This fuel backflow prevention valve opens at the pressure of the fuel flowing in from the fuel supply pipe when refueling, allows the fuel to flow into the fuel tank, is normally closed by elastic means, and the fuel flows back from the fuel tank to the fuel supply pipe. Is prevented.

  As a valve for preventing the back flow of the fuel, in Patent Document 1 below, a tapered valve seat portion is formed on the filler pipe side portion of the valve casing, and the valve body is biased toward the valve seat portion. A valve is disclosed in which an elastic seal member having a lip portion seated on the valve seat portion is attached to the valve body. In the embodiment, the seal member is sandwiched between a main body member and a spring receiving member, and the seal member is formed of a rubber elastic material such as NBR (acrylonitrile butadiene rubber). It is described that.

The following Patent Document 2 includes a slide-type valve body that opens and closes a connection port portion between a fuel tank and a fuel supply pipe, and the valve body extends toward the upstream side of the connection port portion and has an inner wall surface thereof. A valve comprising: a slide member provided with a plurality of guide protrusions that are in sliding contact with each other; an elastic seal member that is in close contact with the rim of the connecting port portion; and a pressing member that presses the elastic seal member toward the slide member. It is disclosed. Further, the embodiment describes that the elastic seal member is sandwiched between a slide member and a pressing member, and the elastic seal member is formed of an elastic material such as rubber. Yes.
Japanese Patent Laid-Open No. 2000-16099 Japanese Patent Laid-Open No. 11-78549

  In either of the above-mentioned valves of Patent Document 1 or 2, a rubber seal member is in contact with and sealed against the valve seat portion of the valve casing or the rim of the connecting port portion to prevent back flow of fuel. However, the rubber seal member can improve the sealing performance efficiently, but has a problem of high cost. Further, since the sealing member is sandwiched between two members, such as a main body member and a spring receiving member in Patent Document 1 and a slide member and a pressing member in Patent Document 2, the number of parts is large, and accordingly, the number of assembling steps is also large. As a result, the cost increases. Furthermore, when the alcohol concentration of the fuel is high, the rubber seal member may swell and deteriorate the sealing performance, or the durability may decrease.

  Accordingly, the object of the present invention is to ensure sufficient sealing performance without using a rubber seal member, to reliably prevent fuel backflow, and to reduce the number of parts and assembly man-hours. Another object of the present invention is to provide a fuel backflow prevention valve capable of reducing the cost.

In order to achieve the above object, a first aspect of the present invention is a housing attached to a fuel tank, one end of which is connected to a fuel supply pipe and the other end being opened in the fuel tank, and a fuel passage of the housing. And a valve body pressed against the valve seat by elastic means from the side communicating with the inside of the fuel tank. The contact surface between the valve seat and the valve body is substantially the same. The valve body has a spherical surface having the same center of curvature, and the valve body extends in a skirt shape by forming a thin plate shape on the periphery of the valve body through the bent portion. Is a spherical surface having the curvature and the center of curvature, and constitutes a contact surface with the valve seat , to provide a fuel backflow prevention valve.

  According to a second aspect of the present invention, there is provided the fuel backflow prevention valve according to the first aspect, wherein a back surface side of the bent portion is recessed in a ring shape to constitute a thin portion.

  According to a third aspect of the present invention, there is provided the fuel backflow prevention valve according to the first or second aspect, wherein ribs extending radially from the center of the back surface of the valve body are formed.

  According to a fourth aspect of the present invention, there is provided the fuel backflow prevention valve according to any one of the first to third aspects, wherein a flat portion is formed on an inner peripheral side from a contact surface of the valve body to the valve seat. To do.

  According to the fuel backflow prevention valve of the present invention, when the fuel is supplied, the valve body is opened against the biasing force of the elastic means by the pressure of the fuel, and the fuel is supplied into the fuel tank. When the operation is completed, the valve body is brought into pressure contact with the valve seat by the elastic means, and the passage is closed to prevent the backflow to the fuel supply pipe, thereby preventing an accident such as fuel blowback during refueling.

  Since the contact surface between the valve seat and the valve body has a spherical surface having substantially the same curvature and substantially the same center of curvature, there is almost no gap between the valve seat and the valve body. Thus, the valve body comes into contact with the valve seat with a wide contact area, and the sealing performance between the valve seat and the valve body can be improved.

  In addition, even if the fuel tank is tilted obliquely due to vehicle shake or the like, and the valve body comes into contact with the valve seat in a slightly tilted state, the valve body and the valve seat contact each other between the spherical surfaces. Even if it hits at any angle, the two are in close contact with each other, and it is possible to prevent deterioration of the sealing performance due to backlash.

  In this way, the sealing performance can be maintained satisfactorily without using a rubber seal member for the valve body, so the number of parts can be reduced and the assembly work of the seal member is not required. Therefore, it is not necessary to worry about the alcohol concentration of the fuel, and the reliability can be improved.

  Hereinafter, with reference to FIGS. 1-7, one Embodiment of the fuel backflow prevention valve of this invention is described.

  As shown in FIG. 1, this fuel backflow prevention valve (hereinafter referred to as valve 10) is attached to a fuel tank, one end of which is connected to a fuel supply pipe, and the other end is opened in the fuel tank. have. The housing 20 includes a lid 30 fixed to the fuel tank 1, and a valve case 40 that is insert-molded with the lid 30 and accommodates the valve body 50 in a slidable manner therein. In the case of this embodiment, the lid 30 is formed of a material that can be welded to a resin fuel tank, for example, an olefin resin such as polyethylene, and the valve case 40 has a high strength and a fuel non-permeable material, for example, It is made of a resin such as polyacetal (POM) or polyamide (PA).

  The lid body 30 has a flange portion 31 welded to the periphery of the opening of the fuel tank, and a connecting pipe portion 32 to which the fuel supply pipe is connected. An annular convex portion 33 is formed on the outer periphery of the distal end portion of the connecting pipe portion 32 to prevent the external pipe from coming off when the fuel supply pipe is fastened and fixed with a hose band or the like. An enlarged diameter step portion 32a is formed below the inner periphery of the connecting pipe portion 32, and four claw portions 32b are formed above the inner periphery of the connecting tube portion 32 at equal intervals in the circumferential direction ( (See FIGS. 1 and 4). Then, the lower end surface of the metal collar 70 is arranged on the diameter-expanded step portion 32a, and the upper end surface of the metal collar 70 is locked by the claw portion 32b, so that the metal collar 70 is fixed to the inner periphery of the connecting pipe portion 32. The metal collar 70 ensures the rigidity of the connecting pipe portion 32 and prevents damage or the like when the external pipe is fastened and fixed.

  Further, the cylindrical wall 34 protrudes in the axial direction from the inner periphery of the flange portion 31, and the annular protrusion 35 protrudes from the periphery of the flange portion 31 toward the inner peripheral direction. These respectively enter grooves 43c and 43e of the valve case 40 described later, and are firmly coupled to the valve case 40. Such a joint structure is formed by insert-molding the lid body 30 on the outer periphery of the flange portion 43b of the valve case 40 molded in advance.

  The valve case 40 shown in FIG. 2 has a case main body 41 in which a plurality of windows 41a in which fuel can freely enter and exit are formed. A plurality of engagement holes 41b are formed in the lower edge of the case main body 41, and an engagement claw of the bottom cover 60 described later is engaged so that the bottom cover 60 can be attached.

  And the cylinder part 43 is extended through the wall part gradually diameter-reduced from this case main-body part 41 upper direction. The inner periphery of the wall portion that gradually decreases in diameter forms the valve seat 42 in the present invention. The valve seat 42 is formed in a spherical shape with a predetermined curvature. More specifically, as shown in FIG. 5, a spherical surface is formed with a predetermined curvature radius R from the center of curvature O, and this surface becomes a contact surface with a seal surface 55 of the valve body 50 described later. . Note that the radius of curvature is defined as the reciprocal of the curvature, that is, if the radius of curvature is large, such as a gentle curve shape, the curvature is small, while if the radius of curvature is small, such as a tight curve shape, the curvature is large. Become. In the case of this embodiment, the center of curvature O is the axial center of the connecting pipe portion 32, and the midpoint in the axial direction of a guide projection 62 described later is the base point.

  Further, an annular projecting portion 43a is provided on the outer side in the circumferential direction above the cylindrical portion 43, and a flange that spreads outward from the wall portion 43d in the circumferential direction through a wall portion 43d that is erected from the inner periphery of the annular projecting portion 43a. A portion 43b is formed. In the flange portion 43b, a plurality of holes 43f are formed at equal intervals in the circumferential direction. When the lid 30 and the valve case 40 are insert-molded, the groove 43e between the distal end peripheral wall of the cylinder 43 and the wall 43d, and the groove between the annular protrusion 43a and the flange 43b. 43c enters the cylindrical wall 34 and the annular protrusion 35 of the lid 30 described above, and further, the melted portion of the lid 30 enters the hole 43f of the flange 43b to increase the bonding strength after insert molding. Then, the lid 30 and the valve case 40 are joined (see FIG. 4).

  A valve body 50 is accommodated in the case body 41 so as to be slidable up and down. The valve body 50 is made of resin such as non-fuel-permeable polyacetal (POM) and has a conical raised portion 51 at the center of the upper surface (see FIG. 3A). Referring also to FIG. 3 (b), four guide blades 52 are erected at an equal interval from the raised portion 51. These guide blades 52 are inserted into the cylindrical portion 43 and serve to guide the slide of the valve body 50.

  Moreover, the flat part 53 has spread from the periphery of the protruding part 51 (refer FIG. 3 (a), (b)). Therefore, when the fuel is supplied, the inflowing fuel collides with the flat portion 53 and easily receives the pressure of the fuel, so that the valve body 50 opens smoothly.

  Further, as shown in FIG. 3D, a skirt-like seal surface 55 is formed extending obliquely outward from the periphery of the flat portion 53 via the bent portion 54. This seal surface 55 becomes a portion that contacts the valve seat 42 of the valve case 40 described above, and closes the fuel passage that communicates with the connecting pipe portion 32. Further, the sealing surface 55 has a spherical shape having substantially the same radius of curvature and center of curvature as the curvature radius R and center of curvature O of the valve seat 42 described above (see FIG. 5).

  Moreover, the back surface side of the bent portion 54 is dented in an annular shape to form a thin portion 54a that is thinner than the flat portion 53 and the seal surface 55 (see FIG. 3D). For this reason, the bent portion 54 is more easily bent, so that the valve seat 42 and the seal surface 55 are more likely to be in close contact with each other, and the sealing performance is improved.

  Further, a guide shaft 56 is suspended from the center of the back surface of the raised portion 51, and a spring receiving portion 57 is formed on the outer periphery of the base end of the guide shaft 56. The spring receiving portion 57 is radially spaced from the periphery of the spring receiving portion 57. A plurality of ribs 58 extending in a straight line are formed (see FIGS. 3A and 3C). The ribs 58 reinforce the valve body 50 and improve the durability. Therefore, even when receiving fuel pressure or external force during fuel supply or when used for a long period of time, The damage of the valve body 50 is effectively prevented.

  A bottom lid 60 is attached to the lower surface of the case main body 41 by engaging a claw 61 provided on the outer periphery thereof with an engagement hole 41 b of the case main body 41. The bottom cover 60 is provided with a guide protrusion 62 projecting from the center thereof, and an annular rib 63 is formed so as to surround the guide protrusion 62, and the lower end of the coil spring 71 is supported inside the rib 63. The guide protrusion 62 enters the guide shaft 56 of the valve body 50 to guide the sliding operation of the valve body 50. The upper end of the coil spring 71 is in contact with the spring receiving portion 57 of the valve body 50, and always biases the valve body 50 upward.

  Next, the operation of the backflow prevention valve 10 will be described.

  This valve 10 is inserted into the opening 2 of the fuel tank 1 shown in FIG. 6, and the flange 31 of the lid 30 is welded to the periphery of the opening 2 by hot plate welding, ultrasonic welding, etc. 1 is attached. Then, one end of the fuel supply pipe 3 is inserted into the outer periphery of the connection pipe part 32 and is fastened and fixed by the hose band 4, and the fuel supply pipe 3 and the fuel tank 1 are connected via the valve 10.

  When fuel is supplied from a fuel supply port (not shown) and fuel is supplied into the fuel supply pipe 3 connected to the fuel supply port, the fuel is connected to the connection pipe portion 32 of the lid 30 and the case body of the valve case 40. When the fuel pressure is applied to the valve body 50 through the fuel passage in the section, the valve body 50 is moved downward against the urging force of the coil spring 71 as shown by the imaginary line of the valve body 50 in FIG. The seal surface 55 of the valve body 50 that is in pressure contact with the valve seat 42 is released from the valve seat 42 and the valve is opened, so that the fuel tank 1 is filled with fuel. When the supply of fuel is completed, the valve body 50 slides upward by the biasing force of the coil spring 71 (see FIG. 4), presses against the valve seat 42 to close the fuel passage, and the pressure in the fuel tank 1 It prevents the fuel from flowing back in the fuel supply pipe and causing the fuel to blow back or the like, or prevents the fuel vapor or the fuel itself from flowing outside even during the fuel supply.

  At this time, the valve seat 42 and the sealing surface 55 of the valve body 50 in contact with the valve seat 42 have substantially the same curvature, in other words, a spherical surface having substantially the same curvature radius R and substantially the same curvature center O. Therefore, the seal surface 55 of the valve body 50 comes into contact with the valve seat 42 with a wide contact area in a state where there is almost no gap between the valve seat 42 and the seal surface 55 of the valve body 50. The sealing performance between the valve seat 42 and the valve body 50 can be improved.

  Further, even when the fuel tank 1 tilts obliquely due to vehicle shake or the like, and the valve body 50 tilts and contacts the valve seat 42, the valve seat 42 and the seal surface 55 of the valve body 50 are not in contact with each other. Since spherical surfaces having substantially the same radius of curvature R and substantially the same center of curvature O are brought into contact with each other, it is possible to prevent deterioration in sealing performance.

  Further, since the rubber seal member is not required for the valve body 50 as in the above-mentioned Patent Documents 1 and 2, the number of parts can be reduced, and the assembly work is also unnecessary, thereby reducing the cost. Can be achieved. Further, since a rubber seal member is not required, there is no need to worry about the alcohol concentration of the fuel, and a highly reliable valve can be obtained.

  The effects of the embodiment described above will be briefly described below.

  That is, according to the present invention, when fuel is supplied, the valve body opens against the urging force of the elastic means to supply fuel into the fuel tank, and when the fuel supply ends, the valve body closes the fuel passage. This prevents backflow of fuel. At this time, the contact surface between the valve seat and the valve body is a spherical surface having substantially the same curvature and center of curvature, so there is almost no gap between the valve seat and the valve body, and the valve seat has a wide contact area. The valve body abuts and the sealing performance is improved. Even if the fuel tank tilts obliquely and the valve body tilts and contacts the valve seat, the spherical surfaces with almost the same curvature and center of curvature are in contact with each other, so that the sealing performance is maintained well. can do. Furthermore, since a rubber seal member is not required, the number of parts is reduced, assembly work is not required, the cost can be reduced, and there is no need to worry about the alcohol concentration of the fuel, resulting in high reliability.

  Moreover, since the sealing surface is provided on the periphery of the valve body via the bent portion, the contact area that contacts the valve seat can be increased, and the sealing performance is further improved.

  Further, since the thin portion is formed on the back surface of the bent portion, the bent portion is more easily bent, the valve seat and the seal surface are more easily adhered, and the sealing performance can be improved.

  Furthermore, since ribs extending radially from the center of the back surface of the valve body are formed, effects such as reinforcement of the valve body and improvement of durability can be obtained, and damage to the valve body can be effectively prevented.

  In addition, a flat portion is formed on the inner peripheral side from the contact surface of the valve body with the valve seat, and the flat portion easily receives fuel pressure when fuel is supplied, so that the valve body opens smoothly.

  In addition, the coil spring 71 in the said embodiment has comprised the elastic means in this invention.

  The sealing performance between the valve seat and the valve body in the fuel backflow prevention valve 10 of the present invention was tested.

Example A valve 10 shown in FIG. 1 was produced. At this time, the lid 30 was made of polyethylene, and the other members except the coil spring 71 were made of polyacetal (POM).

Comparative Example From the valve described in Patent Document 2, a fuel backflow prevention valve was obtained by removing the rubber seal member. This valve is different from the above embodiment in that the sealing surface of the valve body and the valve seat are not spherical.

Test Method Using the valves of the above examples and comparative examples, as shown in FIG. 4, with the valve body abutting against the valve seat and sealing the fuel passage, the fuel pressure of 15 kPa was applied from below the valve case. Pressurized. At that time, it was measured how many cc of fuel leaked from the fuel passage in one minute. In addition, it carried out about three valves in the comparative example, and carried out about five valves in the Example. The results are shown in Table 1.

  From Table 1 above, it can be seen that the valve of the comparative example has an extremely large leakage amount of 41 to 153 cc and a large variation. On the other hand, in the valve | bulb of the Example, it turned out that the amount of leaks is 0.3-1.5cc and is very small compared with a comparative example, and its variation is also comparatively small. Thus, according to the valve of the present invention, it can be understood that the valve body is firmly attached to the valve seat without using a rubber seal member, and a sufficient sealing performance can be obtained stably.

  The present invention is attached to a fuel tank of an automobile or the like, and can secure a sufficient sealing performance without using a rubber seal member to reliably prevent a back flow of fuel. It can be used as a fuel backflow prevention valve that can reduce the number of steps and reduce the cost.

It is a disassembled perspective view which shows one Embodiment of the fuel backflow prevention valve of this invention. It is sectional drawing of the valve case which comprises the fuel backflow prevention valve. The valve body which comprises the same fuel backflow prevention valve is shown, (a) is a front view, (b) is a top view, (c) is a bottom view, (d) is sectional drawing. It is sectional drawing which shows the state which assembled the fuel backflow prevention valve. It is the elements on larger scale explaining the shape of a valve body and a valve seat of the fuel backflow prevention valve. It is explanatory drawing which shows the state which attached the fuel backflow prevention valve to the fuel tank.

Explanation of symbols

1 Fuel Tank 2 Opening 3 Fuel Supply Pipe 10 Fuel Backflow Prevention Valve (Valve)
DESCRIPTION OF SYMBOLS 20 Housing 30 Cover body 31 Flange part 32 Connection pipe part 40 Valve case 41 Case main-body part 42 Valve seat 43 Cylinder part 50 Valve body 51 Raised part 52 Guide blade 53 Flat part 54 Bending part 54a Thin part 55 Seal surface 60 Bottom cover 70 Metal collar 71 Coil spring (elastic means)
O Curvature center R Curvature radius

Claims (4)

A housing attached to a fuel tank, one end of which is connected to a fuel supply pipe and the other end is opened in the fuel tank, a valve seat provided in a fuel passage of the housing, and fuel to the valve seat A valve body pressed by elastic means from the side communicating with the tank, and the contact surface of the valve seat and the valve body has a spherical surface having substantially the same curvature and substantially the same center of curvature. The valve body has a peripheral edge formed in a thin plate shape through a bent portion and extends into a skirt shape, and the skirt-shaped portion forms a spherical surface having the curvature and the center of curvature. A fuel backflow prevention valve comprising a contact surface with a seat .   The fuel backflow prevention valve according to claim 1, wherein a back surface side of the bent portion is annularly formed to constitute a thin portion.   The fuel backflow prevention valve according to claim 1 or 2, wherein ribs extending radially from the center of the back surface of the valve body are formed.   The fuel backflow prevention valve according to any one of claims 1 to 3, wherein a flat portion is formed on an inner peripheral side from a contact surface of the valve body with the valve seat.

Images