JP5085500B2 - Fuel check valve - Google Patents

Description

  The present invention relates to a fuel backflow prevention valve that 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. . When refueling, this fuel backflow prevention valve opens at the pressure of the fuel flowing in from the fuel supply pipe and allows the fuel to flow into the fuel tank, and is always closed by elastic means so that the fuel flows back from the fuel tank to the fuel supply pipe. Is prevented.

  As a valve for preventing the backflow of the fuel, the following Patent Document 1 discloses a fuel backflow prevention valve interposed in a connection port portion between a fuel tank and a fuel supply pipe, and opens and closes the connection port portion. There is disclosed a fuel backflow prevention valve characterized in that a plurality of guide protrusions are provided on the valve body, extending toward the upstream side of the connecting port portion and slidingly contacting the upstream inner wall surface. ing. According to this backflow prevention valve, the plurality of guide protrusions are in sliding contact with the inner wall surface on the upstream side of the connecting port portion, so that the valve body can be slid stably without rattling, and the fuel flow resistance during refueling The sealing performance can be improved when the connecting port is closed. An elastic seal member is attached to the valve body.

In Patent Document 2 below, 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, and a valve seat provided in 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 of the valve seat and the valve body has substantially the same curvature, and substantially A fuel backflow prevention valve is disclosed which has a spherical surface having the same center of curvature.
Japanese Patent Application Laid-Open No. 11-78549 JP 2006-123576 A

  As described above, the fuel backflow prevention valve of Patent Document 1 uses an elastic seal member such as rubber, which increases the manufacturing cost and swells to reduce the sealing performance or the durability. there's a possibility that.

  Further, since the fuel backflow prevention valve of Patent Document 2 seals the molded body surface of the valve body in direct contact with the valve seat, there is no need to use a rubber seal member, and the number of parts can be reduced. Since there is no need to assemble the seal member, the manufacturing cost can be reduced, and there is an advantage that the sealability is not easily lowered due to swelling. On the other hand, there is a problem that the sealability is likely to vary among products.

  Accordingly, an object of the present invention is to provide a fuel backflow that can sufficiently prevent a backflow of fuel by ensuring a sufficient sealing performance by reducing variations among products without using a rubber seal member. It is to provide a prevention valve.

  As a result of examining the cause of variation in each product related to sealing performance in the fuel check valve of Patent Document 2 described above, the present inventor has contact surfaces between the valve body and the valve seat due to sink marks or the like generated during molding of the housing and the valve body. It was found that this was caused by the formation of subtle irregularities on the surface of the valve seat and the variation in the adhesiveness between the two depending on the angle of the valve element relative to the valve seat. And it came to complete this invention by calculating | requiring the angle which a valve seat and a valve body contact | adhere best.

In order to achieve the above object, the first of the present invention is
A housing which is attached to a fuel tank, one end of which is connected to a fuel supply pipe, and the other end which is opened in the fuel tank, constitutes a fuel passage at the time of refueling, and a valve provided in the fuel passage of the housing A seat and a valve body pressed against the valve seat by elastic means from the downstream side of the fuel passage,
A peripheral wall on the downstream side of the fuel passage with respect to the valve seat of the housing is provided with a plurality of pillars extending in the axial direction and an opening formed therebetween,
The valve body is provided with a plurality of guide protrusions extending toward the upstream side of the fuel passage and slidingly contacting the upstream peripheral wall with respect to the valve seat,
A guide groove into which the guide protrusion is inserted is provided on the peripheral wall upstream of the valve seat of the housing,
Each of the housing and the valve body is made of a synthetic resin molded product, and the molding surface of the valve body is configured to be in close contact with the valve seat and sealed.
The fuel backflow prevention valve is characterized in that the position of the guide groove is set so that the guide projection of the valve body is disposed between the column portion of the housing. is there.

  According to the fuel backflow prevention valve of the present invention, the plurality of guide protrusions provided on the valve body are inserted into the guide groove of the housing and are in sliding contact with each other, so that the valve body is stably slid and the valve body is brought into contact with the valve seat. It can be prevented from tilting. In addition, by setting the position of the guide groove so that the guide protrusion of the valve body is disposed between the pillar portions of the housing, a seal surface due to sink marks caused by the guide protrusion of the valve body And the deformed shape of the seal surface of the valve seat due to the sink caused by the pillar portion of the housing are matched, and both are in good contact with each other, so that higher sealing performance can be secured. For this reason, even if it does not use a rubber-made sealing member, the variation for every product can be decreased, sealing property can fully be ensured, and the backflow of fuel can be prevented reliably.

  Further, according to a second aspect of the present invention, in the first aspect of the present invention, the housing is reduced in diameter on the upstream side of the fuel passage with respect to the valve seat, and the guide groove is reduced in diameter in the housing. Provided is a fuel backflow prevention valve formed by partially expanding a peripheral wall radially outward.

  According to the above-described invention, the guide groove is formed by partially expanding the peripheral wall having a reduced diameter of the housing outward in the radial direction, whereby the strength of the housing can be increased. Further, since the guide protrusion of the valve element is inserted into the guide groove and does not protrude greatly into the fuel passage, the fuel flow resistance can be reduced.

  According to the fuel backflow prevention valve of the present invention, as described above, the position of the guide groove is set so that the guide projection of the valve body is disposed between the column portion of the housing. Since the sealing surface of the valve body and the sealing surface of the valve seat are in close contact with each other, even if a rubber seal member is not used, variation between products can be reduced and sufficient sealing performance can be ensured, and fuel backflow can be ensured. It can be surely prevented.

  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, the fuel backflow prevention valve 10 is attached to a fuel tank, and has a housing 20 having one end connected to a fuel supply pipe and the other end opened into the fuel tank. The housing 20 forms a fuel passage for introducing fuel supplied from the fuel supply pipe into the fuel tank. Hereinafter, the side of the fuel passage connected to the fuel supply pipe is referred to as an upstream side, and the side of the fuel passage that opens into the fuel tank is referred to as the downstream side.

  The housing 20 includes a lid 30 fixed to the fuel tank 1 and a valve case 40 that is integrated with the lid 30 by insert molding and accommodates the valve body 50 in a slidable manner. In the case of this embodiment, the lid 30 is formed of a material that can be welded to the resin fuel tank, for example, an olefin resin such as polyethylene, and the valve case 40 is a material having high strength and excellent fuel resistance, For example, it is formed 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. A metal collar 33 is inserted and disposed in the connecting pipe portion 32, thereby ensuring the rigidity of the connecting pipe portion 32 and preventing damage or the like when the external pipe is fastened and fixed.

  On the other hand, the valve case 40 has a cylindrical shape having a reduced diameter portion 41 and an enlarged diameter portion 42.

  Further, as shown in FIG. 2, a valve seat 43 is formed inside a stepped portion 47 provided between the reduced diameter portion 41 and the enlarged diameter portion 42. As shown in the partially enlarged view of FIG. 3, the seal surface 43a of the valve seat 43 (the surface that comes into contact with the valve body 60 described later) is formed in a spherical shape with a predetermined curvature in this embodiment. However, the sealing surface 43a may have another shape such as a tapered shape.

  As shown in FIG. 2, bulging portions 46 extending in a total of four axial directions are formed on the outer periphery of the reduced diameter portion 41 at an angle of approximately 90 degrees in the circumferential direction. The inner periphery of the bulging portion 46 forms a guide groove 45, and the downstream end thereof opens to the inner periphery of the valve seat 43. That is, on the inner periphery of the valve seat 43, the inlets for the guide grooves 45 are arranged at four positions with an angle of approximately 90 degrees. The guide groove 45 can also be configured by a pair of ribs or the like that are provided upright along the axial direction on the inner periphery of the reduced diameter portion 41.

  A plurality of openings 48 are formed in the peripheral wall of the enlarged diameter portion 42, and a pillar portion 49 is formed between them. In the case of this embodiment, the opening 48 is arranged between the four pillars 49 arranged at an angle of approximately 90 degrees. In addition, one of the four columnar parts 49 is formed wider than the other columnar part 49, and the area of the opening 48 adjacent to both sides thereof is narrowed. As shown in FIG. 7, when the fuel tank 1 is mounted, the wide column portion 49a faces upward, so that a large amount of fuel is generated from the wide opening 49 located on the lower side opposite to the column portion 49a. The fuel that has flowed out is prevented from jumping upward.

  Furthermore, as shown in FIG. 5, the positional relationship between the pillar portion 49 and the guide groove 45 is such that the guide groove 45 is located between the pillar portions 49 and they are separated by an angle of approximately 90 degrees. It is set to be arranged at equal intervals.

  A plurality of engagement holes 50 for engaging a cap 70 to be described later are formed on the outer periphery of the end portion of the enlarged diameter portion 42.

  A valve body 60 is accommodated in the enlarged diameter portion 42 of the valve case 40 so as to be vertically slidable. The valve body 60 is made of resin such as polyacetal (POM) having excellent fuel resistance, and has a conical raised portion 61 at the center of the upper surface. Four guide protrusions 62 are erected on the lower edge portion of the raised portion 61 at equal intervals of 90 degrees in the circumferential direction. These guide protrusions 62 are inserted into the guide grooves 45 of the reduced diameter portion 41 and serve to guide the slide of the valve body 60. In the case of this embodiment, the guide groove 45 is formed inside the bulging portion 46, and the guide protrusion 62 inserted into the guide groove 45 does not protrude into the fuel passage, so that the flow path resistance can be reduced.

  Further, as shown in the partially enlarged view of FIG. 3, a flange portion 63 is provided at the periphery of the raised portion 61, and is a surface facing the upstream side of the flange portion 63, and is adjacent to the outer periphery of the raised portion 61. An annular recess 64 is formed in the portion. The annular recess 64 makes it easier for the fuel flowing in during refueling to collide with the pressure of the fuel, so that the valve body 60 opens smoothly.

  Further, a seal surface 65 that is in contact with the seal surface 43 a of the valve seat 43 is formed on the outer periphery of the recess 64, which is a surface facing the upstream side of the flange portion 63. The seal surface 65 has a spherical shape having substantially the same radius of curvature and center of curvature so as to fit the seal surface 43 a of the valve seat 43. However, the seal surface 65 may have another shape such as a taper shape or a curved surface shape.

  As shown in FIGS. 2 and 3, a guide tube 66 is suspended from the center of the back surface of the raised portion 61 of the valve body 60, and a spring receiving portion 67 is formed on the outer periphery of the base end of the guide tube 66. A plurality of ribs 68 extending radially are formed at equal intervals from the periphery of the receiving portion 67 (see FIG. 2). The rib 68 reinforces the valve body 60 and improves 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 60 is effectively prevented.

  A bottom lid 70 is attached to the downstream end of the valve case 40 by engaging a claw 71 provided on the outer periphery thereof with the engagement hole 50 of the case main body 41. The bottom lid 70 is provided with a guide projection 72 projecting from the center thereof, and an annular rib 73 is formed so as to surround the guide projection 72, and the lower end of the coil spring 81 is supported inside the rib 73. Further, the guide protrusion 72 enters the inside of the guide cylinder 66 of the valve body 60 to guide the sliding operation of the valve body 60. The upper end of the coil spring 81 is in contact with the spring receiving portion 67 of the valve body 60, and always biases the valve body 60 upward. The coil spring 81 constitutes an elastic means in the present invention.

  Next, the operation of the fuel backflow prevention valve 10 (hereinafter simply referred to as “valve 10”) will be described.

  The valve 10 is inserted into the opening 2 of the fuel tank 1 shown in FIG. 7, and is attached to the fuel tank 1 by welding the flange 31 of the lid 30 to the periphery of the opening 2 by hot plate welding or the like. . 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.

  Then, 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 passes through the connection pipe portion 32 of the lid body 30 and passes through the valve case. It flows into the fuel passage in 40. Then, the fuel collides with the annular recess 64 of the flange portion 63 of the valve body 60 and effectively receives the pressure of the fuel, so that the valve body 60 resists the urging force of the coil spring 81 as shown in FIG. The valve body 60 moves away from the valve seat 43. As a result, the fuel flows into the enlarged diameter portion 42 of the valve case 40 and flows into the fuel tank 1 through the opening 48 of the enlarged diameter portion 42.

  When the supply of fuel is completed, the valve body 60 slides upstream by the biasing force of the coil spring 81 (see FIG. 3), and the seal surface 65 of the valve body 60 comes into contact with the seal surface 43a of the valve seat 43. Thus, the fuel passage is closed. As a result, it is possible to prevent the fuel from flowing backward in the fuel supply pipe due to the pressure in the fuel tank 1 and causing the fuel to blow back or the like, or the fuel vapor or the fuel itself flows out to the outside even during the fuel supply. To prevent that.

  At this time, in this embodiment, the seal surface 43a of the valve seat 43 and the seal surface 65 of the valve body 60 in contact therewith have substantially the same curvature, in other words, substantially the same curvature radius R, and substantially the same. Since the spherical surfaces having the same center of curvature O are formed, even if the valve body 60 is slightly inclined and abuts against the valve seat 43, good sealing performance can be maintained.

  Furthermore, according to the present invention, the adhesion between the seal surface 43a of the valve seat 43 and the seal surface 65 of the valve body 60 in contact therewith is further improved for the following reason.

  That is, FIG. 5 is a cross-sectional view of the valve case 40 taken along the line VV in FIG. As shown in this figure, the guide grooves 45 are located between the pillar portions 49 and are arranged at equal intervals with an angle of approximately 90 degrees. A guide protrusion 62 of the valve body 60 shown in FIG. 6 is inserted into the guide groove 45. When the valve case 40 having such a shape is injection-molded, a portion A in the vicinity of the column portion 49 of the seal surface 43a of the valve seat 43 due to sink marks caused by the column portion 49 is viewed from the downstream side. There is a tendency to dent, and the portion B located between the pillar portions 49 tends to protrude when viewed from the downstream side.

  On the other hand, as shown in FIG. 6, the seal surface 65 of the valve body 60 has a portion A ′ located between the guide protrusions 62 as viewed from the upstream side due to sink marks during molding caused by the guide protrusions 62. The portion B ′ proximate to the guide protrusion 62 tends to dent when viewed from the upstream side.

  When the guide protrusion 62 of the valve body 60 is inserted into the guide groove 45 of the valve case 40 and the valve body 60 comes into contact with the valve seat 43, the portion close to the column portion 49 of the seal surface 43 a of the valve seat 43. A and a portion A ′ located between the guide protrusions 62 of the sealing surface 65 of the valve body 60 abut. At this time, the former tends to dent when viewed from the downstream side, and the latter tends to protrude when viewed from the upstream side.

  Similarly, when the valve body 60 comes into contact with the valve seat 43, the portion B located between the pillar portions 49 of the seal surface 43 a of the valve seat 43 and the portion close to the guide protrusion 62 of the seal surface 65 of the valve body 60. B 'contacts. At this time, the former tends to protrude when viewed from the downstream side, and the latter tends to dent when viewed from the upstream side.

  Thus, according to the present invention, the adhesion between the sealing surface 43a of the valve seat 43 and the sealing surface 65 of the valve body 60 is improved, so that the sealing performance can be improved and the variation in the sealing performance between products. Can also be reduced.

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

  In FIG. 1 and FIG. 2, the fuel backflow prevention valve has a structure in which the bulging portion 46 and the guide groove 45 are not provided in the valve case 40 and the guide protrusion 62 of the valve body 60 is in sliding contact with the inner periphery of the reduced diameter portion 41 of the valve case 40. 10 was produced.

  And the valve body 60 was arrange | positioned in the valve case 40 by changing the insertion angle of the valve body 60 with respect to the valve case 40. At this time, the following experiment was performed in a state where the guide protrusions 62 of the valve body 60 were arranged at a total of eight positions by shifting the angle by 45 degrees from a certain position aligned with the center of each column part 49 of the valve case 40. It was.

  That is, the maximum amount of air leakage was measured when the air pressure was increased from 0 to 15 kPa from the downstream side of the valve case 40 with the valve body 60 in contact with the valve seat 43 at each arrangement location. .

  Two samples were prepared as the fuel backflow prevention valve 10, and the above experiment was performed on each of them. Table 1 below shows the results of one of the samples, and Table 2 shows the results of another sample.

As shown in the results of Tables 1 and 2, the guide protrusions 62 of the valve body 60 are located between the column parts 49 of the valve case 40, 45 degrees, 135 degrees, 225 degrees, It was found that the sealing performance was very good when the position was 315 degrees.

It is a disassembled perspective view which shows one Embodiment of the fuel backflow prevention valve of this invention. It is a perspective view which shows the valve body and valve case of the fuel backflow prevention valve. It is sectional drawing which shows the valve closing state of the fuel backflow prevention valve. It is sectional drawing which shows the valve opening state of the fuel backflow prevention valve. It is sectional drawing along the VV arrow line of FIG. 4 of the fuel backflow prevention valve. It is explanatory drawing which looked at the valve body of the fuel backflow prevention valve from the upstream side. 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 Diameter reduction part 42 Diameter expansion part 43 Valve seat 43a Seal surface 45 Guide groove 46 Bulging part 48 Opening part 49, 49a Pillar part 60 Valve body 61 Raising part 62 Guide projection 63 Flange portion 64 Annular recess 65 Seal surface 70 Bottom lid 81 Coil spring (elastic means)

Claims (2)

A housing which is attached to a fuel tank, one end of which is connected to a fuel supply pipe, and the other end which is opened in the fuel tank, constitutes a fuel passage at the time of refueling, and a valve provided in the fuel passage of the housing A seat and a valve body pressed against the valve seat by elastic means from the downstream side of the fuel passage,
A peripheral wall on the downstream side of the fuel passage with respect to the valve seat of the housing is provided with a plurality of pillars extending in the axial direction and an opening formed therebetween,
The valve body is provided with a plurality of guide protrusions extending toward the upstream side of the fuel passage and slidingly contacting the upstream peripheral wall with respect to the valve seat,
A guide groove into which the guide protrusion is inserted is provided on the peripheral wall upstream of the valve seat of the housing,
Each of the housing and the valve body is made of a synthetic resin molded product, and the molding surface of the valve body is configured to be in close contact with the valve seat and sealed.
The fuel backflow prevention valve characterized in that the position of the guide groove is set so that the guide projection of the valve body is disposed between the column portion of the housing.   The housing has a diameter reduced on the upstream side of the fuel passage with respect to the valve seat, and the guide groove is formed by partially expanding a diameter-reduced peripheral wall of the housing radially outward. The fuel backflow prevention valve according to claim 1.