JPH0517071B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a breather control valve mounting structure for a fuel tank for a motorcycle.

(Prior art) In order to prevent the volatile fuel in the motorcycle fuel tank from leaking into the atmosphere, the volatile fuel is guided to the canister and adsorbed, and when the motorcycle rolls over, liquid fuel can enter the canister. Breather control valve (breather check valve) to prevent
is known to be used. (For example,
See Publication No. 56-167573. ) In this conventional technology, a breather pipe is installed inside the tank,
The vent at the upper end of the breather pipe faces upward, the lower end of which is led out of the tank through an opening at the bottom of the tank, and the opening and breather pipe are fixed and sealed by welding. The breather control valve is attached to the frame or the like using a mounting fitting, and the breather control valve and the lower end of the breather pipe are connected by piping.

(Problems to be Solved by the Invention) In the prior art, the breather pipe and the breather control valve are fixed separately, and the breather pipe and the breather control valve are connected by piping.
Installation required a lot of work, and the breather control valve and piping took up a considerable amount of space.

The present invention provides a fuel tank for a motorcycle,
The mounting structure between the breather pipe and the breather control valve is simplified, reducing the space required for the mounting structure and the labor required for installation work, and connecting the breather control valve and canister with the shortest pipe without interference with other parts. The purpose is to communicate.

(Means for Solving the Problems) This invention has a breather pipe 5 installed inside the tank 1, with its upper end vent 5a facing upward, and its lower end fixed to the wall at the bottom of the tank 1. A breather control valve 6 (breather check valve) that opens in a vertical position and closes in a horizontal position is connected to the breather pipe 5, and is communicated with a canister 4 located outside and below the tank 1 via a pipe 7. In the breather control valve mounting structure for a motorcycle fuel tank, the lower end of the breather pipe 5 is fixed to the connection fitting 5b fixed to the inner wall surface of the lower part of the tank 1, and the breather control valve 6 is fixed to the connection fitting 5b. The inlet side cylindrical part 28 of the breather control valve 6 is screwed (installed by screwing), and the outlet pipe part 30 of the breather control valve 6 is made substantially perpendicular to the wall surface of the tank 1 to which the breather control valve 6 is attached. Use technical means.

(Example) FIG. 1 shows a motorcycle provided with a fuel tank breather control valve mounting structure of the present invention. Reference numeral 1 denotes a fuel tank, and below the fuel tank 1, an engine 2 supported by a frame, a carburetor 3, a canister 4, etc. are arranged.

FIGS. 2 and 3 are detailed views of the main parts. As shown in these figures, a breather pipe 5 is installed inside the fuel tank 1, and this breather pipe 5 is connected to the canister 4 by a pipe 7 via a breather control valve (breather check valve) 6, the details of which will be described later. is connected to. Canister 4 further has pipe 8
is connected to the upstream side of the carburetor 3.

The fuel tank 1 is constructed by combining a lower plate 1a and an upper plate 1b, each having a saddle-shaped cross section, and seam welding the peripheries of both plates where they contact each other. The lower plate 1a has an upwardly convex central portion, and a frame main pipe 10, wire harness 11, clutch wire 12, accelerator wire 13, etc. are inserted through the lower side of the convex portion.

A stepped portion is formed on the lower plate 1a adjacent to the convex portion, and a breather pipe 5 is provided on the inner wall surface of the stepped portion.
The bottom edge of is fixed. That is, a threaded hole is formed in the center of the connecting fitting 5b from the bottom surface, a communicating hole is bored in the upper part of the threaded hole, and the breather pipe 5 is inserted into this communicating hole.
Insert and secure the bottom end of the An insertion hole (slightly larger than the opening of the screw hole of the connecting fitting 5b) is bored in the stepped part at the bottom of the fuel tank 1, and the connecting fitting 5b is inserted.
The opening of the screw hole and the insertion hole of the fuel tank 1 are brought into contact with each other so that they generally match, and the connecting fitting 5b is fixed to the stepped portion by welding or the like. The breather pipe 5 extends upward inside the fuel tank 1, and has a vent hole 5a at the upper end having a gas-liquid separation function facing the upper space. The male threaded part of the inlet side cylindrical part 28 of the breather control valve 6 is screwed (screwed and installed) into the threaded hole of the connecting fitting 5b through the insertion hole of the fuel tank 1, and the above-mentioned stage of the tank 1 to which the breather control valve 6 is attached is inserted. Breather control valve 6 against the attached wall surface.
The outlet pipe portion 30 of is made substantially vertical. The outlet pipe portion 30 of the breather control valve 6 detachably attached in this manner is connected to the canister 4 via a short pipe 7.

FIG. 4 shows details of the breather control valve 6 mentioned above.

FIG. 4 shows the case where the breather control valve 6 is placed in a vertical position, and the case 2 forming the outer shell is shown in FIG.
0, an inlet-side cylindrical portion 28 is formed on the upper end side, a male threaded portion 29 is provided on the outer peripheral surface of the inlet-side cylindrical portion 28, and an opening 21 is provided on the upper end. Case 2
An outlet pipe portion 30 is connected to the lower end of the canister 0, and an opening 22 communicating with the canister 4 is provided at the lower end. Inside this case 20, there is a weight 23.
is supported at its lower end by a spring 24 and is movable along the inner wall.
Further, a valve body 25 is provided at the upper part of the inside of the inlet-side cylindrical portion 28 of the case 20 so as to face the opening 21 and to be movable up and down. It is supported on the upper surface of the weight 23. In this case, the spring 27
The elastic force of the spring 24 is set to be smaller than that of the spring 24.

When the breather control valve 6 is in the vertical position shown in the figure, the weight 23 is pulled by the spring 24 due to its gravity.
The valve element 25 is in contact with the bottom surface of the case 20 against the elastic force of the weight 23, and the valve body 25 is also located below and apart from the opening 21, following the weight 23. Therefore, in this state, the breather pipe 5 and the canister 4 are in communication with each other through the gap in the case 20, and gasified fuel flows therethrough.

Now, suppose that the breather control valve 6 changes from the vertical position shown in the figure to the horizontal position, as a result of the vehicle overturning or the like. Then, the axial component of the gravity of the weight 23 acting on the spring 24 becomes smaller. Therefore, the elastic force of the spring 24 overcomes the sum of the axial component force of the weight 23 and the frictional force, and the weight 23 is moved so that the valve body 25 is pushed toward the opening 21. As a result, the opening 21 is closed by the valve body 25, and even if the liquid fuel in the fuel tank 1 flows into the breather pipe 5 due to the liquid level movement during sudden acceleration/deceleration, this breather control valve 6 prevents the liquid fuel from flowing into the canister 4. It does not flow to the side.

In the case of the breather control valve 6 of the above embodiment, a spring 27 is provided between the weight 23 and the valve body 25.
is provided, so that even if the temperature inside the fuel tank 1 rises and dents, and the pressure inside the tank increases, for example, when the valve body 25 closes the opening 21, Above spring 2
By contracting 7, the increase in internal pressure can be alleviated.

Furthermore, in the above embodiment, the breather control valve 6 is installed in the stepped recess formed in the lower plate 1a of the fuel tank 1, so that the breather control valve 6 can be attached from the outside by the upper plate 1b. Moreover, they are installed in the space areas each surrounded by the lower plate 1a from the inside via the main pipe 10. Therefore, the breather control valve 6 does not interfere with other parts or the rider's feet.

〔Effect of the invention〕

In the present invention, the lower end of the breather pipe 5 is fixed to the connecting fitting 5b fixed to the inner wall surface of the lower part of the tank 1, and the inlet side cylindrical part 28 of the breather control valve 6 is screwed to the connecting fitting 5b. The mounting structure between the breather control valve and the breather control valve is extremely simple and can be completely sealed. And, unlike the conventional technology, there is no need to attach the breather control valve to a frame etc. using a mounting bracket, or to connect the breather control valve and the lower end of the breather pipe with piping.
The space required for the mounting structure and the amount of work required for installation work are extremely reduced.

In the present invention, the outlet pipe portion 30 of the breather control valve 6 is made substantially perpendicular to the wall surface of the tank 1 to which the breather control valve 6 is attached, so that the mounting angle can be adjusted at any position when the screwing operation is completed. Even if
Breather control valve 6 without being interfered with by other parts.
The pipe 7 that communicates the outlet pipe portion 30 and the canister 4 can be made as short as possible. (if,
If the outlet pipe section 30 of the breather control valve 6 is bent, the mounting angle by screwing and the direction of the outlet pipe section 30 are unstable, so the outlet pipe section 30 and the pipe 7 interfere with other parts. )

[Brief explanation of the drawing]

Fig. 1 is a side view of a motorcycle equipped with the structure of the present invention, Fig. 2 is a side view showing a main part of the structure of the present invention in partial cross section, and Fig. 3 is a cross section taken in the direction of - arrow in Fig. 2. 4 are longitudinal sectional views of a breather control valve used in the same structure. DESCRIPTION OF SYMBOLS 1... Fuel tank, 2... Engine, 5... Breather pipe, 5a... Ventilation hole, 5b... Connection fittings, 6... Breather control valve, 7... Pipe, 28... Inlet side cylinder part, 30
...Exit pipe.

Claims (1)

[Claims] 1 A breather pipe 5 is installed inside the tank 1, with its upper end vent 5a facing upward, and its lower end fixed to the wall at the bottom of the tank 1, and the breather pipe 5
A fuel tank for a motorcycle, in which a breather control valve 6 that is open in a vertical position and closed in a horizontal position is connected to the fuel tank, and the fuel tank is connected to a canister 4 located outside and below the tank 1 via a pipe 7. 1 Connection fitting 5 fixed to the lower inner wall surface
b, the lower end of the breather pipe 5 is fixed to the connecting fitting 5b, and the inlet side cylinder part 2 of the breather control valve 6
A breather control valve mounting structure characterized in that an outlet pipe portion 30 of the breather control valve 6 is made substantially perpendicular to the wall surface of the tank 1 to which the breather control valve 6 is attached.