JP4155345B2 - Valve structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve structure that can reliably maintain airtightness even when the accuracy of a valve seat surface is low.
[0002]
[Prior art]
Conventionally, various valve structures have been used at various locations. Here, FIG. 6 shows a conventional general valve structure for opening and closing a steam passage from a fuel tank of an automobile to a canister. A communication passage 52 to a canister (not shown) is formed integrally with the upper portion of the case 50, and the case 50 is fixed to the upper wall of the fuel tank 54. The case 50 is exposed to the inside of the fuel tank 54, and a cap 58 having a hole 56 is attached to the lower side of the case 50 exposed to the inside of the fuel tank 54. The case 50 includes a float 60 and a spring 62 interposed between the float 60 and the cap 58.
The upper surface of the float 60 is a dome-shaped valve body 64. In a normal state, the valve body 64 is set so as not to contact a valve seat 66 formed on the case 50.
[0003]
Under normal conditions, the inside of the fuel tank 54 and the communication passage 52 communicate with each other via the inside of the case 50, so that when fuel gas is generated inside the fuel tank 54, the fuel gas is It is led from the inside to the canister via the communication passage 52.
On the other hand, if the vehicle is excessively inclined or falls, the fuel enters the case 50, the float 60 rises, the valve body 64 contacts the valve seat 66, and the communication passage 52 communicates with the inside of the fuel tank 54. And shut off. This prevents the fuel in the fuel tank 54 from flowing out through the canister during tilting or the like.
When the inclination of the automobile is settled, the fuel is discharged from the inside of the case 50 to the fuel tank side so that the valve body 64 is not in contact with the valve seat 66, and the inside of the fuel tank 54 and the canister are communicated again. .
In such a conventional configuration, the float 60 having the valve body 64 and the case 50 having the valve seat 66 are formed by resin molding or cutting. However, the accuracy of the valve body 64 and the valve seat 66 by resin molding and cutting is limited, and there is a problem that the valve airtightness cannot be surely achieved.
[0004]
As a valve structure for solving this problem, Japanese Utility Model Laid-Open No. 7-38660 is provided, and this valve structure is shown in FIG. The case 70 has a space 72 therein, and the space 72 communicates with a communication passage 76 that communicates with a canister (not shown) through a communication hole 74 formed in the upper portion of the case 70. A cap 80 having a hole 78 is attached to the lower portion of the case 70. The case 70 includes a float 84 having a convex portion 82 formed on the upper portion thereof, a ball 86 interposed between the float 84 and the cap 80, and a valve member 88 for opening and closing the communication passage 76. It is done. The valve member 88 includes a guide member 90 (see FIG. 8) formed of a plurality of radial fins fitted into the communication hole 74, and a base portion on which a convex surface portion 92 for making point contact with the convex surface portion 82 of the float 84 is formed. 94 and a sealing member 96 having elasticity such as rubber attached to the outside of the base 94. An annular rib 98 is formed on the seal member 96, and the annular rib 98 comes into contact with the valve seat surface 100 formed on the inner upper surface of the case 70.
[0005]
[Problems to be solved by the invention]
In the structure in which the elastic sealing member 96 formed with the annular rib 98 contacts the valve seat surface 100, the valve member 88 including the sealing member 96 is pushed by the float 84, and the annular rib 98 of the sealing member 96 is pressed. Comes into contact with the valve seat surface 100 of the case 70. Since the annular rib 98 has elasticity, the annular rib 98 reliably contacts the valve seat surface 100 even if the valve seat surface 100 formed by resin molding has some undulation. Thereby, valve airtightness can be ensured.
However, this structure has an advantage that valve tightness can be ensured, but has a disadvantage that the number of parts is increased and the cost is increased. Furthermore, if the base 94 and the seal member 96 are not properly assembled, the seal member 96 may be distorted, and the valve airtightness may not be ensured only by the elasticity of the seal member 96. Assembling accuracy was required, and there was a problem that the manufacturing cost was high.
[0006]
The present invention has been made in view of the above points, and provides a low-cost valve structure that can ensure high airtightness even if the accuracy of the valve seat surface is not required, is easy to assemble, and has a small number of parts. .
[0007]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention forms a communication hole that connects one space and the other space in the case, and is provided in the one space, and is formed of an annular material made of an elastic material. A valve seat, an annular rib provided to project on the surface of one side of the valve seat, and an annular rib provided on the other surface of the valve seat so as to project from the annular rib. A valve seat surface formed around the communication hole of the case, an operating member for pressing the valve seat against the valve seat surface of the case, and formed in the operating member, the annular And a valve seat surface formed around the guide member in the operating member, the valve seat being another member. Fixed to It shall not be, that when pressing the valve seat by an actuating member and the casing, the ribs of the annular provided on a surface of one side of the valve seat is formed in the case by actuating the actuating member An annular rib provided on the other side surface of the valve seat contacts the valve seat surface and contacts the valve seat surface formed on the actuating member to block the communication hole.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described with reference to the drawings.
1 and 2 are cross-sectional views showing an embodiment of a valve structure according to the present invention. FIG. 1 shows an open state, and FIG. 2 shows a closed state.
The case 10 has a space (one space) 12 therein, and the space 12 communicates with a communication passage (the other space) 16 leading to a canister (not shown) through a communication hole 14 formed in the upper part of the case 10. Has been. A cap 20 in which a hole 18 is formed is attached to the lower part of the case 10. The case 10 is exposed inside the fuel tank, and the space 12 in the case 10 communicates with the inside of the fuel tank through the hole 18 of the cap 20. A communication hole 22 is also formed on the side surface of the case 10, and the space 12 in the case 10 communicates with the inside of the fuel tank through the communication hole 22.
[0009]
Inside the space 12 of the case 10, an inverted cup-shaped float 24 as an operating means and a spring 26 interposed between the float 24 and the cap 20 are provided.
On the upper surface of the float 24 corresponding to the cup-shaped bottom surface, as shown in FIG. 3, a guide member 28 made up of a plurality of fins arranged radially and extending upward is integrally formed. The guide member 28 is set so as to be fitted into the communication hole 14 formed in the case 10. Since the guide member 28 fitted to the communication hole 14 is composed of a plurality of radial fins, the communication hole 14 normally connects the space 12 and the communication passage 16.
[0010]
Around the guide member 28 arranged radially, an annular valve body, that is, a valve seat 30 made of a material that is not fixed to other members and has elasticity is provided. That is, the guide member 28 is for preventing the annular valve seat 30 from shifting laterally. The annular valve seat 30 is sized such that there is a difference between the inner diameter and the outer diameter. As shown in FIG. 4, an annular rib 32 protruding upward is formed on the upper surface of the valve seat 30, and an annular rib 34 protruding downward is formed on the lower surface of the valve seat 30. The diameter of the annular rib 32 and the diameter of the annular rib 34 are set to be different. For example, as shown in FIG. 4, the diameter of the annular rib 32 on the upper surface is approximately equal to the intermediate diameter between the inner diameter and the outer diameter of the valve seat 30, and the diameter of the annular rib 34 on the lower surface is approximately the same as that of the valve seat 30. Set to equal to outer diameter. The valve seat 30 is formed with a rib 36 having a notch with a diameter substantially equal to the inner diameter of the lower surface of the valve seat 30.
The inner surface of the case 10 facing the annular rib 32 on the upper surface of the valve seat 30 is a valve seat surface 38, and the upper surface of the float 24 facing the annular rib 34 on the lower surface of the valve seat 30 is a valve seat surface 40.
[0011]
According to the valve structure configured as described above, as shown in FIG. 1, when the oil level 42 is located at a lower position, the rib 34 and the rib 36 of the valve seat 30 are caused by gravity to the valve seat surface of the float 24. 40 is contacted. However, the valve seat 30 is not in contact with the valve seat surface 38 of the case 10. Therefore, in the state of FIG. 1, the space 12 and the communication passage 16 are in communication with each other through the communication hole 14.
Next, in the state of FIGS. 2 and 4 in which the oil level 42 in the fuel tank enters the space 12 of the case 10 and the float 24 rises, the valve seat 30 is sandwiched between the case 10 and the float 24. Will cause pressure on both sides. As a result, the annular rib 32 on the upper surface of the valve seat 30 contacts the valve seat surface 38 of the case 10, and the annular rib 34 on the lower surface of the valve seat 30 contacts the valve seat surface 40 of the float 24. Since these annular ribs 32 and 34 have elasticity, even if the valve seat surfaces 38 and 40 formed by resin molding have undulations, the annular ribs 32 and 34 reliably contact the valve seat surfaces 38 and 40. To do. Thereby, the space 12 side of the communication hole 14 is closed in a state in which airtightness is ensured.
[0012]
In the present invention, airtightness is maintained even if the valve seat 30 is in contact with the valve seat surface 40 at a position smaller in diameter than the rib 32 on the opposite surface of the valve seat 30 on the side where the rib 34 having a large diameter is formed. The ribs 36 without any problems were formed. The rib 36 has a notch in the middle of an annular shape, for example. This is because, when the shape of the valve seat 30 is such that the rib 36 is not formed (see FIG. 5), the valve seat 30 has a surface on which the rib 34 having a large outer diameter is formed and the valve seat surface of the float 24. A space 44 is formed between the valve seat 40 and the air in the space 44, and the valve seat 30 may be adsorbed to the valve seat surface 40 of the float 24. Providing the valve seat 30 with the rib 36 that does not maintain hermeticity even when it contacts the valve seat surface 40 is to prevent the valve seat 30 from being adsorbed by the valve seat surfaces 38 and 40. Further, if the ribs 36 are not provided on the valve seat 30, the balance of the valve seat 30 is deteriorated, which is also prevented.
Even if the valve seat 30 sticks to the valve seat surfaces 38 and 40 without providing the rib 36, the vertical movement of the float 24 is not hindered, and the fuel gas is discharged when the valve is opened. A route can be secured, and airtightness when the valve is closed can be secured.
The effect is the same even if the vertical direction of the valve seat 30 is changed. In the above description, the airtightness can be ensured, but the flow of fluid including water can be prevented.
[0013]
【The invention's effect】
As described above, according to the valve structure according to the present invention, both sides of the valve seat made of a material having elasticity are brought into contact with the valve seat surface to ensure airtightness. Therefore, since the valve body can be constituted by only the valve seat, the cost of the valve body is low. Further, since the valve seat does not need to be fixed anywhere, it is easy to assemble.
In the present invention, since airtightness is ensured by utilizing both sides of a valve seat made of an elastic material, even if the valve seat surface formed by resin molding or the like has some undulation, the valve airtightness is maintained. It can be surely secured. In addition, the effect is particularly great for large-diameter valve seats in which the swell of the valve seat surface increases.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an opened state of an embodiment of a valve structure according to the present invention.
FIG. 2 is a cross-sectional view showing an opened state of an embodiment of a valve structure according to the present invention.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is an enlarged cross-sectional view of a valve seat used in the present invention.
FIG. 5 is a cross-sectional view of a valve seat not provided with a notched rib.
FIG. 6 is a cross-sectional view of a conventional valve structure.
FIG. 7 is a cross-sectional view of another conventional valve structure.
8 is a cross-sectional view taken along line BB in FIG.
[Explanation of sign]
DESCRIPTION OF SYMBOLS 10 Case 12 Space 14 Communication path 24 Float 28 Guide member 28 Communication hole 30 Valve seat 32 Annular rib 34 Annular rib 36 Rib 38 which formed the notch Valve seat surface 40 Valve seat surface

Claims (4)

A communication hole that connects one space and the other space is formed in the case, and an annular valve seat that is provided in one space and is made of an elastic material, and one side of the valve seat An annular rib provided on the surface of the valve seat, an annular rib having a diameter different from that of the annular rib, provided on the other surface of the valve seat, and formed around the communication hole of the case A valve seat surface, an actuating member for pressing the valve seat against the valve seat surface of the case, and formed on the actuating member and fitted to the annular valve seat, includes a guide member for eliminating the lateral offset, and a valve seat formed around the guide member in the actuating member, said valve seat shall not be fixed to another member, the actuating member is created When the valve seat is pressed by the actuating member and the case, an annular rib provided on one surface of the valve seat comes into contact with the valve seat surface formed on the case and the valve seat A valve structure characterized in that an annular rib provided on a surface on the other side contacts a valve seat surface formed on an operating member to block the communication hole. Even if the valve seat is in contact with the valve seat surface at a diameter smaller than the diameter of the annular rib having a small diameter on the opposite side surface of the valve seat on which the annular rib is formed, the airtightness is not maintained. The valve structure according to claim 1, wherein a rib is formed. An annular rib that does not maintain hermeticity even if it contacts the valve seat surface 40 at a position smaller in diameter than the rib on the opposite surface on the surface of the valve seat on which the rib having a large diameter is formed. 3. The valve structure according to claim 2, wherein a notch is formed in the middle of the annular shape of the rib that is formed and does not maintain its airtightness. The valve structure according to claim 1, wherein the guide member is fitted with the communication hole, and fluid can pass through the communication hole in the fitted state.

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