Flow control valve

Abstract

To improve the releasability of a seal member during being molded, the seal member being provided in a flow control valve and having an undercut portion.SOLUTION: The flow control valve comprises a housing 31 having a passage 33, a valve seat 37 provided midway in the passage 33, a valve element 51 moved in the axial direction to thereby open / close the valve seat 37, and a seal member 70 provided between the valve seat 37 and the valve element 51 and sealing between both members during closing the valve. The seal member 70 has a base portion 72 mounted on the valve element 51, and a conically cylindrical seal lip 73 protruded from the surface of the base portion 72. In the surface of the base portion 72, a recessed portion 74 is formed continuously with the inner periphery of the seal lip 73.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a flow control valve used in an evaporated fuel treatment device mounted mainly on a vehicle. [Background technology]

[0002] In order to maintain the pressure inside the fuel tank at an appropriate pressure in a sealed state, some evaporated fuel processing devices are equipped with a positive pressure relief valve that opens when the pressure inside the fuel tank is equal to or greater than a predetermined positive pressure value, and a negative pressure relief valve that opens when the pressure inside the fuel tank is equal to or less than a predetermined negative pressure value (see Patent Document 1). Note that the positive pressure relief valve in Patent Document 1 corresponds to the flow control valve referred to in this specification.

[0003] Fig. 9 is a cross-sectional view showing a seal member according to a conventional example. As shown in Fig. 9, an annular seal member 170 made of an elastic body seals between the valve member 151 and a valve seat member (not shown) when the valve member 151 is closed. The seal member 170 has an annular plate-shaped base portion 172 attached to the valve member 151, and a conical cylindrical seal lip 173 obliquely protruding axially inward from a surface (the lower surface in Fig. 9) of the base portion 172. The seal lip 173 has a substantially constant wall thickness 173T, a lip angle 173θ, a lip center length 173L, and a forced removal width 173W. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-121791 A Summary of the Invention [Problem to be solved by the invention]

[0005] When molding the seal member 170 of the conventional example, the inner peripheral space of the seal lip 173 becomes the undercut portion 173U, so that the seal lip 173 is forcibly deformed and released from the mold by a forced release molding. However, there was a problem that the seal lip 173 was prone to molding defects such as tears and underfill during release, and the mold releasability was poor.

[0006] The problem to be solved by the technique disclosed in this specification is to improve the releasability during molding of a seal member having an undercut portion provided in a flow control valve. [Means for solving the problem]

[0007] In order to solve the above problems, the technique disclosed in this specification takes the following measures.

[0008] The first means is a flow control valve comprising: a housing having a fluid passage; an annular valve seat member provided in the passage; a valve member that opens and closes the valve seat member by moving in the axial direction; and an annular seal member made of an elastic body that is provided between the valve seat member and the valve member and seals between the two members when the valve is closed, wherein the seal member has an annular base portion attached to one of the two members, and a conical cylindrical seal lip that protrudes obliquely axially inward from a surface of the base portion, the seal lip being separated from the other of the two members when the valve member is open and elastically contacting the other member when the valve member is closed, and wherein a surface of the base portion is formed with an annular recess that has an inner wall surface that is continuous with the inner circumferential surface of the seal lip and that is continuous in the circumferential direction.

[0009] According to the first aspect, a ring-shaped recess having an inner wall surface continuous with the inner peripheral surface of the seal lip and continuing in the circumferential direction is formed on the surface of a base portion of a seal member having an undercut portion provided in a flow control valve. Therefore, the lip center length of the seal lip is extended by an amount equivalent to the depth of the recess, thereby improving the flexibility of the seal lip. This improves the mold releasability during molding of the seal member.

[0010] The second means is a flow control valve according to the first means, wherein the seal lip is formed to have a cross section tapered from the base end side toward the tip end side.

[0011] According to the second measure, the releasability of the seal member during molding can be further improved.

[0012] A third means is a flow control valve according to the first or second means, wherein an inner wall surface of the recess has a concave curved surface having an arc-shaped cross section that is smoothly continuous with the inner circumferential surface of the seal lip.

[0013] According to the third means, it is possible to disperse the stress generated when the seal lip is deformed, and to suppress deterioration of the seal lip.

[0014] A fourth aspect of the present invention is a flow control valve according to the third aspect, in which the concave curved surface and the surface of the base portion are smoothly connected by a convex curved surface having an arc-shaped cross section.

[0015] According to the fourth means, it is possible to disperse the stress generated when the seal lip is deformed, and to suppress deterioration of the seal lip. Effect of the Invention

[0016] According to the technique disclosed in this specification, it is possible to improve the releasability during molding of a seal member having an undercut portion provided in a flow control valve. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram showing a configuration of an evaporated fuel treatment device according to an embodiment; [Diagram 2] FIG. 2 is a cross-sectional view showing a relief valve device. [Diagram 3] FIG. 4 is a cross-sectional view showing an open state of a positive pressure relief valve of the relief valve device. [Figure 4] FIG. 4 is a cross-sectional view showing an open state of a negative pressure relief valve of the relief valve device. [Diagram 5] FIG. 4 is a bottom view showing the first valve member provided with a sealing member. [Figure 6] 6 is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 4 is a cross-sectional view showing a first seal lip. [Figure 8] FIG. 4 is a cross-sectional view showing a first seal lip when the valve is closed. [Figure 9] FIG. 11 is a cross-sectional view showing a sealing member according to a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment for carrying out the technology disclosed in this specification will be described with reference to the drawings. The flow control valve of this embodiment is provided as a positive pressure relief valve of a relief valve device of an evaporated fuel treatment device mounted on a vehicle such as an automobile equipped with an internal combustion engine. Therefore, after describing an overview of the evaporated fuel treatment device, the positive pressure relief valve will be described together with the relief valve device.

[0019] (Outline of the fuel vapor treatment device) Fig. 1 is a configuration diagram showing an evaporated fuel processing device. As shown in Fig. 1, in an evaporated fuel processing device 10, evaporated fuel evaporated in a fuel tank 12 passes through a vapor passage 13 and is adsorbed by an adsorbent such as activated carbon in a canister 17. A shutoff valve 14 consisting of an electrically operated on-off valve is provided in the vapor passage 13. A bypass passage 15 that bypasses the shutoff valve 14 is provided in the vapor passage 13. A relief valve device 30 is provided in the bypass passage 15. The fuel in the fuel tank 12 is supplied to an internal combustion engine (engine) 24 by a fuel supply device 20 through a fuel supply path 22.

[0020] The canister 17 is connected to an intake passage 26 of the internal combustion engine 24 via a purge passage 18. A purge valve 19 is disposed in the middle of the purge passage 18. When the purge valve 19 is opened at a predetermined timing while the internal combustion engine 24 is in operation, the evaporated fuel in the canister 17 is supplied to the intake passage 26 through the purge passage 18 by utilizing the intake negative pressure of the internal combustion engine 24. The closing valve 14 and the purge valve 19 are controlled to be opened and closed by an engine control unit (hereinafter referred to as "ECU") 28.

[0021] Furthermore, while the vehicle is parked, the shut-off valve 14 is maintained in a closed state, thereby blocking the vapor passage 13. As a result, the evaporated fuel in the fuel tank 12 does not flow into the canister 17. Furthermore, during refueling, the shut-off valve 14 is opened, thereby opening the vapor passage 13, so that the evaporated fuel in the fuel tank 12 passes through the vapor passage 13 and is adsorbed by the adsorbent in the canister 17. Furthermore, when the shut-off valve 14 is closed while the vehicle is parked, the pressure in the fuel tank 12 is maintained at an appropriate pressure by the relief valve device 30.

[0022] (Relief valve device 30) Fig. 2 is a cross-sectional view showing the relief valve device 30. The up-down and left-right directions of the relief valve device 30 are determined based on Fig. 2, but the arrangement direction of the relief valve device 30 is not specified. As shown in Fig. 2, the relief valve device 30 includes a housing 31, a positive pressure relief valve 50, and a negative pressure relief valve 60. The relief valve device 30 may be arranged, for example, so that the axial direction is oriented in the up-down direction with respect to the vehicle.

[0023] (Housing 31) The housing 31 has a housing body 32, a cover 40, and a retaining member 42. The internal space of the housing 31 serves as a fluid passage 33. The housing body 32 is formed of a resin material in a cylindrical shape with a bottom. A first communication port 34 communicating with the passage 33 is formed in the center of the bottom wall of the housing body 32. A second communication port 35 communicating with the passage 33 is formed in the side wall of the housing body 32.

[0024] The first communication port 34 is connected to the fuel tank 12 via a passage portion on the fuel tank 12 side of the bypass passage 15 of the evaporated fuel processing device 10 (see FIG. 1) and the vapor passage 13. The second communication port 35 is connected to the canister 17 via a passage portion on the canister 17 side of the bypass passage 15 of the evaporated fuel processing device 10 (see FIG. 1) and the vapor passage 13.

[0025] A circular plate-shaped valve seat 37 is concentrically disposed on the bottom wall of the housing body 32. The valve seat 37 is made of a metal material and is integrated with the bottom wall by insert molding. The valve seat 37 corresponds to the "valve seat member" and "other member" in this specification.

[0026] The cover 40 is made of a resin material and has a cap shape. The cover 40 closes the upper end opening of the housing main body 32. The retaining member 42 is made of a resin material and has an annular shape. The retaining member 42 is joined to the upper end of the side wall of the housing main body 32 and the outer periphery of the cover 40 by welding or the like.

[0027] (Positive Pressure Relief Valve 50) The positive pressure relief valve 50 is incorporated concentrically within the housing 31. The positive pressure relief valve 50 opens and closes the valve seat 37 by moving in the axial direction (up and down direction). In other words, the positive pressure relief valve 50 is normally closed, and opens when the pressure on the first communication port 34 side, i.e., the fuel tank 12 side, becomes equal to or higher than the valve opening pressure on the positive pressure side. In Figure 2, the positive pressure relief valve 50 and the negative pressure relief valve 60 are shown in a closed state. The positive pressure relief valve 50 corresponds to the "flow control valve" as referred to in this specification.

[0028] A valve body (referred to as the "first valve body") 51 of the positive pressure relief valve 50 is disposed within the housing 31 so as to be movable in the axial direction, i.e., the up-down direction. The first valve body 51 has a first valve plate portion 51a in the shape of an annular plate, and an axis portion 51b and a cylinder portion 51c which are formed concentrically on the first valve plate portion 51a and have an inner and outer double cylinder shape. The first valve body 51 corresponds to the "valve member" and "one member" as referred to in this specification.

[0029] The first valve plate portion 51a has an outer diameter smaller than the inner diameter of the side wall of the housing main body 32. The first valve plate portion 51a has an outer diameter larger than the outer diameter of the cylindrical portion 51c. When the first valve body 51 is closed, the first valve plate portion 51a (specifically, the outer periphery) closes the valve seat 37 of the housing 31 via the seal member 70. The first valve plate portion 51a is formed with a plurality of communication holes 52 (two are shown in FIG. 2) penetrating in the plate thickness direction (vertical direction). The communication holes 52 are arranged around the shaft portion 51b. The shaft portion 51b is higher than the height of the cylindrical portion 51c.

[0030] A first spring 55 made of a coil spring is concentrically interposed between the first valve plate portion 51a and the cover 40. The first spring 55 biases the first valve body 51 downward, i.e., in the closing direction. The lower end of the first spring 55 is disposed adjacent to the inner circumferential surface of the cylindrical portion 51c of the first valve body 51.

[0031] The upper surface of the valve seat 37 and the lower surface of the first valve plate portion 51a of the first valve body 51 are flat surfaces facing each other. A circular ring-shaped seal member 70 is attached to the lower surface of the first valve plate portion 51a. The seal member 70 will be described later.

[0032] (Negative pressure relief valve 60) The negative pressure relief valve 60 is incorporated concentrically with the positive pressure relief valve 50 within the housing 31. The negative pressure relief valve 60 opens and closes by moving in the axial direction (up and down direction) with the first valve plate portion 51a of the first valve body 51 as a valve seat. That is, the negative pressure relief valve 60 is normally closed, and opens when the pressure on the fuel tank 12 side falls below the negative pressure side valve opening pressure.

[0033] The valve body (referred to as the "second valve body") 61 of the negative pressure relief valve 60 has a circular plate-shaped second valve plate portion 61a and a hollow valve shaft portion 61b that protrudes from the inner periphery of the second valve plate portion 61a, which are arranged concentrically. The valve shaft portion 61b is arranged within the shaft portion 51b of the first valve body 51 so as to be movable in the axial direction, i.e., the up-down direction. A circular plate-shaped spring receiving member 62 is attached to the tip portion (upper end portion) of the valve shaft portion 61b.

[0034] The second valve plate portion 61a has an outer diameter smaller than the inner diameter of the first communication port 34. When the second valve body 61 is closed, the second valve plate portion 61a closes the first valve plate portion 51a of the first valve body 51 (more specifically, the portion surrounding the multiple communication holes 52) via the seal member 70.

[0035] A second spring 65 made of a coil spring is concentrically interposed between the spring receiving member 62 and the first valve plate portion 51a. The lower end of the second spring 65 is disposed in a portion surrounding the plurality of communication holes 52 of the first valve body 51. The second spring 65 biases the second valve body 61 upward, i.e., in the closing direction. The biasing force of the second spring 65 is smaller than that of the first spring 55.

[0036] (Operation of the relief valve device 30) Assume now that the shutoff valve 14 provided in the evaporated fuel processing device 10 (see FIG. 1) is in a closed state, and both relief valves 50, 60 of the relief valve device 30 are in a closed state (see FIG. 2). That is, the first valve plate portion 51a of the first valve body 51 is seated on the valve seat 37 via the seal member 70 by the urging of the first spring 55. Also, the second valve plate portion 61a of the second valve body 61 is seated on the first valve body 51 via the seal member 70 by the urging of the second spring 65. As a result, the passage 33 is blocked.

[0037] In this state, when a positive pressure equal to or greater than the valve opening pressure is generated on the fuel tank 12 side, the positive pressure relief valve 50 opens. That is, as shown in FIG. 3, the first valve body 51 rises against the bias of the first spring 55, that is, the valve is opened. At this time, the seal member 70 separates from the valve seat 37, opening the passage 33. As a result, the fluid from the fuel tank 12 flows through the passage 33 to the canister 17 (see the arrow in FIG. 3). This reduces the pressure inside the fuel tank 12.

[0038] Furthermore, when a negative pressure equal to or lower than the valve opening pressure of the negative pressure relief valve 60 occurs on the fuel tank 12 side, the negative pressure relief valve 60 opens. That is, as shown in FIG. 4, the second valve body 61 moves down against the bias of the second spring 65, i.e., opens the valve. At this time, the second valve plate portion 61a of the second valve body 61 moves away from the seal member 70, thereby opening the passage 33 via the communication hole 52. Therefore, the fluid from the canister 17 flows through the passage 33 including the communication hole 52 to the fuel tank 12 side (see the arrow in FIG. 4). This causes the pressure in the fuel tank 12 to increase.

[0039] (Sealing member 70) Fig. 5 is a bottom view showing the first valve body 51 equipped with a seal member, and Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. As shown in Fig. 6, the seal member 70 is attached to the underside of the first valve plate portion 51a of the first valve body 51 by integral molding. The seal member 70 is made of a rubber-like elastic body. The inner and outer circumferential portions of the upper surface of the seal member 70 are formed with engagement portions 71a, 71b that engage with a plurality of (two are shown in Fig. 6) engagement holes 53a, 53b formed in the first valve plate portion 51a.

[0040] The seal member 70 has an annular plate-shaped base portion 72, a first seal lip 73 formed on the outer periphery of the lower surface 72a of the base portion 72, and a second seal lip 77 formed on the inner periphery of the lower surface 72a of the base portion 72 (see FIG. 5). The upper surface of the base portion 72 is attached to the lower surface of the first valve plate portion 51a of the first valve body 51. The lower surface 72a of the base portion 72 corresponds to the "surface" as referred to in this specification. The first seal lip 73 will be explained after the second seal lip 77.

[0041] The second seal lip 77 is formed in a conical cylindrical shape that protrudes obliquely axially inward from the inner peripheral part of the lower surface of the base portion 72. On the outer peripheral surface of the second seal lip 77, a protrusion 77a having a triangular cross section is formed in an annular shape.

[0042] When the second valve body 61 is closed (see FIG. 2), the second valve plate portion 61a elastically contacts, i.e., closely contacts, a tip portion including a protrusion 77a of the second seal lip 77 of the seal member 70. This provides a seal between the second valve body 61 and the first valve body 51. When the second valve body 61 is opened (see FIG. 4), the second valve plate portion 61a is separated from the second seal lip 77 of the seal member 70, causing the second seal lip 77 to elastically return to its original shape.

[0043] (First seal lip 73) Fig. 7 is a cross-sectional view showing the first seal lip 73. As shown in Fig. 7, the first seal lip 73 is formed in a conical cylindrical shape that protrudes obliquely axially inward from the outer periphery of the lower surface of the base portion 72. The first seal lip 73 corresponds to the "seal lip" as referred to in this specification.

[0044] The first seal lip 73 is formed to have a cross section that tapers from the base end side toward the tip end side. That is, the thickness 73T of the first seal lip 73 becomes smaller from the base end side toward the tip end side. The tip end portion of the first seal lip 73 is rounded.

[0045] The first seal lip 73 has an inner peripheral surface 73a that forms an acute angle with respect to a lower surface 72a of the base portion 72. The angle between the lower surface 72a and the inner peripheral surface 73a is referred to as a lip angle 73θ. The seal lip 73 has a lip center length 73L and a forced removal width 73W. When the seal member 70 is molded, the inner peripheral side space of the seal lip 73 becomes an undercut portion 70U.

[0046] An annular recess 74 is formed on the lower surface 72a of the base portion 72, the recess 74 having an inner wall surface continuing in the circumferential direction and continuing with the inner circumferential surface 73a of the first seal lip 73. The inner wall surface of the recess 74 has a concave curved surface 74a having an arc-shaped cross section that smoothly continues with the inner circumferential surface 73a of the first seal lip 73. The concave curved surface 74a and the lower surface 72a of the base portion 72 are smoothly continued by a convex curved surface 74b having an arc-shaped cross section.

[0047] When the first valve body 51 is closed, the tip of the first seal lip 73 elastically contacts, i.e., adheres closely to, the upper surface of the valve seat 37 (see FIG. 8). At this time, the first seal lip 73 elastically deforms so as to fall radially inward and upward, thereby sealing the gap between the first valve body 51 and the valve seat 37. When the first valve body 51 is opened, the first seal lip 73 is separated from the valve seat 37, and the first seal lip 73 elastically returns to its original shape (see FIG. 7).

[0048] Advantages of an embodiment According to this embodiment, an annular recess 74 is formed on the lower surface 72a of the base portion 72 of the seal member 70 having the undercut portion 70U provided in the positive pressure relief valve 50, the recess 74 having an inner wall surface continuing to the inner peripheral surface 73a of the first seal lip 73 and continuing in the circumferential direction. Therefore, compared with the lip center length 173L (see FIG. 9) of the seal lip 173 of the conventional example, the lip center length 73L of the first seal lip 73 is extended by an amount equivalent to the depth of the recess 74, and the flexibility, i.e., the flexibility, of the first seal lip 73 is improved. This improves the mold releasability during molding of the seal member 70.

[0049] Moreover, the first seal lip 73 is formed to have a cross section that tapers from the base end side toward the tip end side. This can further improve the mold releasability during molding of the seal member 70. Here, the thickness 73T of the tip end of the first seal lip 73 is set to be equal to the thickness 173T (see FIG. 9) of the seal lip 173 of the conventional example, and gradually increases toward the base end. Therefore, compared to the seal lip 173 of the conventional example, it is possible to increase the elasticity of the base end side of the first seal lip 73 while improving the flexibility, i.e., flexibility, of the tip end side.

[0050] Furthermore, the lip angle 73θ of the first seal lip 73 is set to be approximately 20° larger than the lip angle 173θ (see FIG. 9) of the conventional seal lip 173. This is effective in improving the mold releasability during molding of the seal member 70.

[0051] Furthermore, the forced removal width 73W of the first seal lip 73 is set slightly smaller than the forced removal width 173W of the conventional seal lip 173. This is effective in improving the mold releasability when the seal member 70 is molded.

[0052] Moreover, the inner wall surface of the recess 74 has a concave curved surface 74a having an arc-shaped cross section that smoothly continues with the inner circumferential surface 73a of the first seal lip 73. This makes it possible to disperse stress when the first seal lip 73 is deformed, and to suppress deterioration of the first seal lip 73.

[0053] In addition, the inner wall surface of the recess 74 and the lower surface 72a of the base portion 72 are smoothly connected by a convex curved surface 74b having an arc-shaped cross section. This makes it possible to disperse stress when the first seal lip 73 is deformed, and to suppress deterioration of the first seal lip 73.

[0054] [Other embodiments] The technology disclosed in this specification is not limited to the above-mentioned embodiment, and can be embodied in various other forms. For example, the technology disclosed in this specification may be applied not only to the positive pressure relief valve 50 of the evaporated fuel processing device 10, but also to the negative pressure relief valve 60 and relief valves of other devices. In addition, a portion including the first seal lip 73 of the seal member 70 may be attached to the valve seat 37 instead of the first valve body 51. In addition, the base portion 72 of the seal member 70 may be attached to the first valve plate portion 51a of the first valve body 51 by adhesion, welding, or the like. In addition, the cross-sectional shape of the recess 74 of the seal member 70 may be changed as appropriate. [Explanation of symbols]

[0055] 30 Relief valve device 31 Housing 33 Passage 37 Valve seat (valve seat member, other member) 50 Positive pressure relief valve (flow control valve) 51 First valve body (valve member, one member) 70 Sealing material 72 Base 72a Bottom surface (front surface) 73 First seal lip (seal lip) 73a Inner surface 74 Recess 74a Concave surface 74b Convex curved surface

Claims

1. a housing having a fluid passage; an annular valve seat member provided midway through the passage; a valve member that opens and closes the valve seat member by moving in an axial direction; a ring-shaped seal member made of an elastic material provided between the valve seat member and the valve member to seal between the two members when the valve is closed; It is equipped with the seal member has an annular base portion attached to one of the two members, and a conical cylindrical seal lip protruding obliquely axially inward from a surface of the base portion, a seal lip that is spaced from the other of the two members when the valve member is opened and that is elastically contacts the other member when the valve member is closed, a surface of the base portion having an inner wall surface continuous with the inner circumferential surface of the seal lip and a circular recess continuing in a circumferential direction, the surface of the base portion being formed with the inner wall surface continuing with the inner circumferential surface of the seal lip;

2. 2. The flow control valve according to claim 1, The seal lip is formed to have a cross section that tapers from a base end side to a tip end side.

3. 3. The flow control valve according to claim 1 or 2, a concave curved surface having an arc-shaped cross section that smoothly continues into the inner circumferential surface of the seal lip;

4. 4. The flow control valve according to claim 3, A flow control valve, wherein the concave surface and the surface of the base portion are smoothly connected by a convex surface having an arc-shaped cross section.

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