JPH0211318Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fuel tank cap for motorcycles and other vehicles.

Conventionally, this type of cap was equipped with a breather passage that communicated the inside of the fuel tank with the outside air.
An exhaust valve that opens when the internal pressure of the tank rises above a certain value is interposed in the breather passage, and the exhaust valve can prevent an excessive rise in the internal pressure of the tank and fuel leakage through the breather passage when the tank is tilted. Although such a system is known, in this system, the breather passage does not effectively separate gas and liquid, resulting in a lot of wasteful discharge of gasoline.

The purpose of the present invention is to provide a cap that eliminates such inconveniences.The fuel tank cap is provided with a breather passage that communicates the inside of the fuel tank with the outside air, and the breather passage is connected to the internal pressure of the fuel tank. In the device provided with an exhaust valve that opens when the rise exceeds a certain value, the exhaust valve is formed of a breathable valve body made of a sintered material, and a gas-liquid separation chamber is connected to the valve chamber having the exhaust valve through a communication hole. is formed in the breather passage, and a return passage connected to the fuel tank is provided in the separation chamber.

Next, the present invention will be explained with reference to the illustrated embodiments.

In the drawings, 1 is a fuel tank, 2 is an inlet of the tank 1, and 3 is a cap fitted to the inlet 2. Guide frame 6 that slides
A gasket 7 is provided and urged downward via the guide frame 6, and a cylinder lock 8 is provided at the center of the upper surface, and the gasket 7 is airtightly joined to the upper surface of the mouth edge of the inlet 2. At the same time, a pair of left and right latching pieces 8a, 8a interlocked with the cylinder lock 8 are latched to the lower surface of the mouth edge. In the illustrated embodiment, a breather passage 9 is formed in the cap 3 as follows.

That is, the cap 3 surrounding the cylinder lock 8
As clearly shown in FIG. 2, a recessed hole 10 on one side in the circumferential direction and a recessed groove 11 extending approximately all the way around the peripheral wall, leaving the recessed hole 10, are formed in the peripheral wall of the recessed hole 10. and the recessed groove 11 are covered with a seal rubber 12 on the upper surface, and an opening 1 is provided at the bottom of the recessed hole 10 that extends into the fuel tank 1.
3 and is biased by a spring 14b to close the opening 13 in the recessed hole 10.
4a to form a valve chamber 10a in the recessed hole 10, and a seal rubber 12 that slopes downward from one end to the other end as clearly shown in FIG. A gas-liquid separation chamber 16 is formed in the space below an integrated guide wall 15, and a communication hole 17 is provided that communicates the inside of the valve chamber 10a with an upper end of the gas-liquid separation chamber 16, A breather hole 18 is formed in the seal rubber 12 on the upper surface of the other end of the separation chamber 16, and the inside of the fuel tank 1 is connected between the valve chamber 10a, the communication hole 17, the gas-liquid separation chamber 16, and the breather hole 18. A breather passage 9 is configured to communicate with the outside air through the air passage.

In the drawing, reference numeral 19 indicates a liquid chamber formed at the lower end of the cap 3, and the liquid chamber 19 is connected to the gas-liquid separation chamber 16 via a return passage 20 at the bottom of the other end, and a drain valve at the lower side thereof. 21 into the fuel tank 1. In the illustrated embodiment, the drain valve 21 is a membrane type valve that is closed by the internal pressure of the tank 1.

In the figure, 22 indicates a lid member that covers the cylinder lock 8 and can be opened and closed.

According to the present invention, the valve body 14a of the exhaust valve 14 is configured to have air permeability.

To explain this in more detail, the valve body 14a is made of a porous material such as sintered metal or sintered resin.

Next, to explain its operation, even if the internal pressure of the fuel tank 1 does not reach a predetermined set pressure that causes the exhaust valve 14 to open, the air in the fuel tank 1 flows through the breather passage 9 due to the air permeability of the valve body 14a. Unless the internal pressure suddenly increases due to some abnormality, the internal pressure will be maintained below the set pressure, and a large amount of air will not flow into the gas-liquid separation chamber 16 at once. Although the capacity of the cap 3 is small, gas and liquid are sufficiently separated in the chamber 16, and the separated air is discharged to the outside from the breather hole 18, and the liquid fuel is is returned into the tank 1 from the return passage 20 via the drain valve 21.

Note that when the tank 1 is tilted, if the valve body 14a is made of a porous material, fuel may seep out from the breather passage 9 through the valve body 14a, but the amount of this seepage is small. There are no practical problems.

In this way, according to the present invention, the exhaust valve 14 provided in the breather passage 9 of the fuel tank cap 3 is
Since this is formed into a breathable valve body made of sintered material, the internal pressure inside the tank will not normally rise to the level that would cause the exhaust valve 14 to open, and the air inside the tank will flow into the breather passage 9 at once. Since there is no inflow, the breather passage 9 can be made smaller, and the air inside the tank that passes through the valve body is fragmented by the passage, increasing the unit surface area of gasoline particles and increasing the amount of heat dissipation. A gas-liquid separation chamber 16 is formed in the breather passage 9, which facilitates liquefaction and is connected to the valve chamber 10a having the exhaust valve 14 through a communication hole 17, and a return passage 20 is connected to the separation chamber 16 into the tank 1. Since this is provided, gas-liquid separation within the separation chamber 16 is performed more effectively, and gasoline is not wasted into the atmosphere.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of one example of the present device, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 3 is a developed view taken along the line -- in FIG. DESCRIPTION OF SYMBOLS 1... Fuel tank, 3... Fuel tank cap, 9... Exhaust valve, 10a... Valve chamber, 14... Exhaust valve, 14a... Valve body, 16... Gas-liquid separation chamber, 1
7...Communication hole, 20...Return passage.

Claims (1)

[Scope of utility model registration request] The fuel tank cap is provided with a breather passage that communicates the inside of the fuel tank with the outside air, and the breather passage is provided with an exhaust valve that opens when the internal pressure of the fuel tank rises above a certain value, and the exhaust valve is made of sintered material. A gas-liquid separation chamber connected to the valve chamber having the exhaust valve through a communication hole is formed in the breather passage, and a return passage connected to the fuel tank is provided in the separation chamber. A fuel tank cap featuring