JPH0520938Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to an improvement of the internal pressure side valve of a fuel check valve or other two-way valve that is incorporated into a fuel system such as a gasoline engine.

(Prior Art) A conventional two-way valve, for example, a fuel check valve 1, is disposed between a fuel tank 2 and a carbon canister 3, as shown in FIG. When the internal pressure of the fuel tank becomes lower than atmospheric pressure, the second valve 4 (Fig. 8) opens to allow fuel vapor to flow to the canister side, while the first valve 5 opens when the internal pressure of the fuel tank becomes lower than atmospheric pressure. This mutual adjustment prevents damage to the fuel tank.

The second valve 4 is usually an annular body made of an elastic material such as rubber, and its base is fixed to the valve holder 6, and the end plate 7a of the housing 7 is connected to the end plate 7a of the housing 7.
The side end portion is a thin-walled lip portion 8, and its inner wall is tapered, and has a sealing surface 8a that comes into contact with the valve seat 9 formed on the end plate 7a, and a pressure receiving surface 8b continuous to the center thereof. with sealing surface 8
The valve a is pressed toward the valve seat 9 by a spring 10, and the valve is opened by an internal pressure of several tens of millimeters of mercury.

(Problems to be Solved by the Invention) In the conventional two-way valve described above, only the sealing surface 8a of the lip portion 8 deforms elastically in response to the set load of the spring 10, and the pressure receiving surface 8b does not deform and reduces the pressure receiving area. The structure is designed to ensure that

However, when the elasticity of the valve 4 weakens, for example when a fuel check valve is significantly immersed in fuel, the pressure receiving surface 8b, which is thin like the sealing surface, cannot withstand the spring load and deforms, causing the valve seat 9 to deform. (see Figure 7C). In this case, since the area of the pressure receiving surface that substantially functions as a pressure receiving part is reduced, the valve 4 will not open unless the pressure is higher than the predetermined pressure, and its operating pressure will fluctuate.

One possible solution to the above problem is to make the lip part more elastic, but if the elasticity is made stronger, the fit between the sealing surface 8a and the valve seat 9 will deteriorate, the sealing performance will decrease, and leakage will increase. A problem arises.

As described above, stabilizing the operating pressure of the valve and ensuring sealing performance are not compatible with each other.

[Means for solving problems]

In this invention, a cylindrical valve holder with a bottom is installed in the housing, a first valve is provided at the bottom of the valve holder that is opened by negative pressure on the inside of the valve, and the inside of the valve is provided on the opening side of the valve holder. A two-way valve is provided with a second valve that opens and closes a communication hole communicating with both sides, and a pressure spring is installed between the bottom of the valve holder and the housing, the second valve having elasticity. It is an annular body whose base is fixed to the valve holder, and the end on the housing side is a thin lip part whose inner wall is tapered, and the lip part is continuous with the sealing surface that comes into contact with the housing and its center side. By forming a convex portion on the pressure receiving surface that does not enclose any area, the sealing performance of the lip portion is ensured and deformation that causes fluctuations in the operating pressure is prevented. This made it possible.

(Function of the device) In this device, the sealing surface formed on the lip portion of the second valve comes into contact with the valve seat and seals that portion, thereby preventing fluid from leaking from the inside of the valve. The pressure-receiving surface receives pressure from the inside to open and close the valve, which is the same as in the conventional one. The protrusion provided on the pressure-receiving surface acts as a stopper between the valve seat and the pressure-receiving surface against spring pressure, preventing the pressure-receiving surface from coming close to or coming into contact with the valve seat, thereby reducing the pressure-receiving area. This is to prevent this from happening. Therefore, in this invention, due to the presence of the convex portion, variation in the pressure receiving area is prevented while maintaining the elasticity of the lip portion, and the above-mentioned conventional problems are solved.

Hereinafter, embodiments of this invention will be described based on the drawings.

(Example) The two-way valve of this invention will be explained by taking a fuel check valve as an example.

The basic structure of the fuel check valve 1 is the same as that of the conventional one. That is, as shown in FIG. 2, a bottomed cylindrical valve holder 6 is installed in the housing 7, and a first valve 5 that opens when the pressure on the fuel tank side is reduced is provided at the bottom of the valve holder 6. A second valve 4, which opens when the fuel tank side pressure is high, is fixed to the opening side of the valve holder 6. The second valve 4 is an annular body made of an elastic material, and its base portion is fixed to the valve holder 6, and its tip portion is a thin lip portion 8. The inner wall of the lip portion 8 is tapered, and has a sealing surface 8a which abuts against a valve seat 9 formed around an end plate 7a having a communication hole 11 with the fuel tank of the housing 7, and a sealing surface 8a continuous to the sealing surface 8a. It has a surface 8b. The valve holder 6 is urged toward the end plate 7a by a spring 10 installed between the valve holder 6 and the housing. In the figure, 12 is a communication hole with the carbon canister 3.

As shown in FIG. 3, on the outer periphery of the pressure receiving surface 8b, a plurality of small protrusions 13 are formed concentrically at equal intervals as convex portions. The small protrusion 13 acts as a stopper and closes the valve seat 9 of the pressure receiving surface 8b when immersed in fuel.
Since it prevents contact with the valve seat 9, its size and density may be such that a gap can be maintained between the pressure receiving surface 8b and the valve seat 9. And the pressure receiving surface 8b
When provided on the outer periphery, a low height is sufficient, but when provided on the center side, a relatively high height is required.

In this embodiment, since the small protrusion 13 contacts the valve seat and supports the pressure receiving surface 8b like a spacer,
Even if the elasticity of the lip portion 8 is weakened, the pressure receiving surface 8b will not come into contact with the valve seat. Therefore, there is no change in the pressure-receiving area, and the second valve 4 opens at the designed pressure. Furthermore, since the pressure receiving surface 8b does not come into contact with the valve seat, minute vibrations caused by the passage of fuel vapor through this portion are not generated, reducing the causes of abnormal noise generation, and a reduction in abnormal noise generation can be expected.

The ones in Figures 4, 5, and 6 are all modified examples of the second valve body used in the present application, and the one in Figure 4 has a plurality of spiral protrusions formed on the pressure receiving surface 8b. This is what constitutes the convex portion 14.

In this example as well, the convex portion 14 acts as a stopper and can prevent the pressure receiving surface 8b from coming into contact with the valve seat, so that the pressure receiving area does not fluctuate, as in the above embodiment.

Next, in the one in FIG. 5, the convex portion 14 is arc-shaped,
Multiple pieces are formed in concentric circles.

In this example as well, the convex portion 14 functions as a stopper, as in each of the above embodiments.

Next, in the one shown in FIG. 6, a plurality of convex portions 14 are formed radially outward from the center of the lip portion 8.

Although various specific examples of the shapes of the convex portions have been shown above in the examples shown in FIGS. 3 to 6, other specific forms of the convex portions can be considered. The point is that the convex portion acts as a stopper to prevent the pressure receiving surface from coming into contact with the valve seat.

(Effects of the device) According to this device, a convex portion is formed on the pressure receiving surface of the lip portion of the second valve that opens when the inward pressure of the two-way valve increases, so that the convex portion is attached to the valve seat. The pressure-receiving surface is supported at a distance from the valve seat by contacting the valve seat. That is, the sealing surface and the pressure-receiving surface are clearly separated functionally, making it possible to prevent fluctuations in the pressure-receiving area and eliminating the risk of fluctuations in the operating pressure of the valve.

Also, since the pressure receiving surface does not come into contact with the valve seat,
It is possible to reduce minute vibrations of the lip portion that occur due to leakage of fuel vapor, etc., and to suppress as much as possible the generation of abnormal noises caused by minute vibrations.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the installed state of the fuel check valve, Fig. 2 is a sectional view of an embodiment of the invention, Fig. 3 is a modification of the second valve of the invention, and A is a plan view. , B is a sectional view, C is a partially enlarged end view, FIG. 4 also shows a modification of the second valve, and A
is a plan view, B is a sectional view, C is a partially enlarged end view, FIG. 5 is a plan view of a modification of the second valve, FIG. 6 is a modification of the second valve, and A is a plan view. Figure, B
7 shows a partially enlarged end view, FIG. 7 shows a second valve of the conventional example, A is a plan view, B is a sectional view, C is a sectional view when immersed in fuel, and FIG. 8 is a sectional view of the conventional example. be. 1... Fuel check valve, 2... Fuel tank, 3... Canister, 4... Second valve, 5
...First valve, 6... Valve holder, 7... Housing, 8... Lip, 8a... Seal surface, 8b
...Pressure receiving surface, 9...Valve seat, 13...Protrusion, 14...
...Convex stripes.

Claims (1)

[Claims for Utility Model Registration] 1. A cylindrical valve holder with a bottom is installed in a housing, and a first valve that is opened by an inward negative pressure is provided at the bottom of the valve holder, and an opening of the valve holder is provided. A two-way valve is provided with a second valve on the side for opening and closing a communication hole communicating with the inner side, and a pressure spring is installed between the bottom of the valve holder and the housing, the second valve being It is an elastic annular body whose base is fixed to the valve holder, and its housing side end is a thin lip with a tapered inner wall and a sealing surface that comes into contact with the housing and a pressure-receiving surface that is continuous with the sealing surface. A two-way valve comprising a convex portion that does not enclose any area on the pressure receiving surface. 2. The two-way valve according to claim 1, wherein the convex portion is a plurality of small protrusions. 3. The two-way valve according to claim 1 of the utility model registration claim, in which the convex portion is a convex strip. 4. The two-way valve according to claim 3 of the utility model registration claim, in which the protrusions are provided in a spiral, concentric, or radial pattern.