JPH0867282A - Fuel tank cap for motorcycle - Google Patents

Abstract

PURPOSE: To provide a fuel tank cap for a motorcycle concurrently having a breather function and a liquid leak preventing function. CONSTITUTION: Relating to a fuel tank cap for a motorcycle, it has a ventilating path 10 made fittable/mountable in a mouth part of a fuel tank to provide a check valve 9 built in so as to connect the inside/outside and a ventilating path 12 built in with a felt 11. Accordingly, in a position just above the ventilating path 10 having the check valve 9 and the ventilating path 12 having the felt 11, in the tank cap, a pressure reducing chamber 13, having a plurality of chambers 16 partitioned by vertical/horizontal direction partitioning walls 14, 15, is internally provided, and each chamber 16 of this pressure reducing chamber 13 is connected by a ventilating hole 17 in at least two or more parts, to form a labyrinth structure.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fuel tank cap for a motorcycle.

[0002]

2. Description of the Related Art A fuel tank cap for a motorcycle is
Various measures have been taken to prevent fuel from flowing out when the motorcycle body falls, when it is suddenly braked, or when the internal pressure rises, which is characteristic of motorcycles.

Conventionally, a breather is provided separately from a tank cap for sealing a fuel inlet of a fuel tank, a chamber of the breather is located in the fuel tank, and a breather is connected to the chamber and has a check ball built therein. There is an external structure in which is located outside the fuel tank, or a breather is integrally provided in the tank cap. This is a breather having a valve structure in which positive and negative pressure valves are provided in a cap.

[0004]

However, in the case where the breather is provided separately from the tank cap,
The cost is high and the structure is complicated. Also, there was no one with a breather with a valve structure integrated into the tank cap in terms of performance. Particularly in high-speed vehicles equipped with cowlings, it was often the case that the breather function could not be dealt with during heat damage or sudden braking.

In view of this, an object of the present invention is to provide a fuel tank cap for a motorcycle which has a breather function only by the tank cap, has a simple structure and can be obtained at low cost.

[0006]

As a means for solving the problems of the above-mentioned prior art, the present invention provides a vent passage that is fitted to the mouth of a fuel tank and has a built-in check valve so that the inside and outside communicate with each other. In a fuel tank cap for a motorcycle having a ventilation passage having a built-in felt, a vertical and horizontal partition wall is provided in a position directly above the ventilation passage having the check valve and the ventilation passage having a felt in the tank cap. A decompression chamber having a plurality of chamber chambers is provided internally, and each chamber chamber of the decompression chamber is connected to at least two or more vent holes to form a labyrinth structure.

[0007]

The air or gas in the fuel tank reaches the decompression chamber through the ventilation passage having the check valve and the ventilation passage having the felt. In the decompression chamber, the pressure is reduced while flowing through the ventilation holes into the chamber chambers partitioned by the vertical and horizontal partition walls, and then is sequentially discharged to the upper chamber chamber and then released into the atmosphere. Even if the liquid tries to flow out during sudden braking or falling, it is prevented by the decompression chamber and is prevented from flowing out.

[0008]

The present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 1 shows a cross section of an embodiment of the fuel tank cap according to the present invention, and FIG. 2 shows a cross section corresponding to the line A--A of FIG. 1. In FIG. 1, 1 is the outer wall of the fuel tank. The upper surface of the portion where the mouth 2 is provided is recessed, and the base is pivotally attached to the fuel tank 1 side by a hinge 5 so that the cap 4 can be opened and closed so that the cap 4 is located in the recess 3. There is.

The cap 4 has a seal portion 6 which comes into close contact with the upper end 2a of the mouth portion 2 to prevent liquid leakage when closed, and a portion fitted into the mouth portion 2, that is, an inner body 7.
There is a lock member 8 at the lower part of the cap 4, and the lock member 8 is locked so as not to open by rotating the lock member 8 from the outside after fitting.

As shown in FIG. 2, the inner body 7 has a ventilation passage 10 communicating with the upper and lower surfaces thereof and having a check valve 9 and a felt passage 11 therein.
A decompression chamber 13 is built right above these ventilation passages 10 and 12 so as to straddle both ventilation passages 10 and 12.

The decompression chamber 13 is formed as a molded product made of plastic, and FIG.
As shown in the plan view, the vertical partition wall 14 and the horizontal partition wall 15 form a plurality of chambers 16, 1.
6 are partitioned and formed, and each chamber chamber 16, 16 ...
Ventilation holes 17 and 17 are formed at least at two locations in the partition walls 14 and 15 that partition the chamber 1,
6, 16 ... Are connected in a maze.

Therefore, the air or gas in the fuel tank 1 passes through the ventilation passage 10 having the check valve 9 and the ventilation passage 12 having the felt 11, reaches the decompression chamber 13, and vents 17 to the chamber chambers 16, 16 ... , 1
The pressure is reduced while flowing through 7, and gradually flows into the upper chamber chambers 16, 16 ...

On the other hand, even if the internal liquid flows into the ventilation passages 17 and 17 when the motorcycle falls or is suddenly braked, if it reaches the decompression chamber 13, it does not go through the chamber chambers 16, 16 ... Therefore, the liquid is prevented from flowing out.

[0015]

As described above, according to the present invention, since the decompression chamber formed as a cartridge structure only has to be fitted into a predetermined position of the cap, there is no need to change the structure of the cap itself. It can be obtained at a significantly low cost, yet has an excellent breather function for air and gas, and can reliably prevent leakage of liquid, and thus can be made sufficiently superior in performance to conventional products.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view corresponding to line AA in FIG.

FIG. 3 is a plan view of the decompression chamber portion.

[Explanation of symbols]

 1 Fuel Tank 2 Port 4 Cap 7 Inner Body 9 Check Valve 10 Ventilation Path 11 Felt 12 Ventilation Path 13 Decompression Chamber 14, 15 Partition Wall 16 Chamber Chamber 17 Ventilation Hole

Claims (1)

[Claims] Claims: 1. A fuel tank cap for a motorcycle, comprising a ventilation passage having a check valve and a ventilation passage having a built-in felt so that the fuel tank can be fitted into the mouth of the fuel tank and communicates with the inside and outside. A decompression chamber having a plurality of chamber chambers partitioned by vertical and horizontal partition walls is provided directly above the ventilation passage having the check valve and the ventilation passage having a felt, and each chamber chamber of the decompression chamber is provided. Is a fuel tank cap for a motorcycle, which has a maze structure in which at least two vent holes communicate with each other.