JPH0631053B2 - Breather device for fuel tanks for motorcycles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a breather device for a fuel tank for a motorcycle.

(Prior Art) A breather device is generally provided in a fuel tank of a motorcycle. This device is configured as follows, for example. That is, a separator that separates fuel and gas is provided in the fuel tank. Then, one end side of the communication passage formed in the separator opens into the fuel tank, and the other end side is connected to the canister device.

Here, as is well known, the above-mentioned canister device means that the vaporized gas generated in the fuel tank is once adsorbed by an adsorbing means such as activated carbon, and the gas is sucked into the cylinder of the engine when the engine is operating. However, if the adsorbing means of the canister device adsorbs the fuel in a liquid state, the device cannot perform its original function.

By the way, in the breather device, since the separator is provided in the fuel tank, when the fuel tank is almost filled with the fuel, a sufficient gap cannot be secured between the separator and the liquid surface of the fuel. Therefore, since the separator is likely to be immersed in the fuel due to the fluctuation of the liquid level due to traveling of the vehicle or the like, the fuel may remain in the liquid state and easily flow into the canister device through the separator.

Therefore, for example, as shown in Japanese Utility Model Laid-Open No. 55-114793, the communication passage is formed in a cap provided on the top of the tank body of the fuel tank, and the communication passage is formed as high as possible from the liquid surface of the fuel. It is possible to pull it away.

(Problems to be Solved by the Invention) However, as described above, even when the communication passage is formed in the cap located at the top of the tank body, when the vehicle is in a horizontal position, There is a problem in that the fuel remains liquid and flows through the communication passage toward the canister device.

(Object of the Invention) The present invention has been made by paying attention to the above circumstances, and prevents the fuel in the tank body from flowing into the canister device even when the vehicle is laid down in a horizontal posture.
Moreover, even if a new component is provided for this purpose, the main purpose is to prevent the appearance of the vehicle from being deteriorated and prevent the component from being stolen easily.

(Structure of the Invention) A feature of the present invention for achieving the above object is that a communication passage is formed in a cap provided at the front top of the tank body, and the communication passage is connected to a canister device via a communication pipe. When connected, a check valve that prevents the fuel in the tank body from flowing toward the canister device through the communication passage and the communication pipe is provided in the middle of the communication pipe. This check valve is attached to the inside of the tank body and to the lower front portion of the tank body.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 is a motorcycle, and an engine 3 is mounted on its body frame 2.
And a fuel tank 4 for supplying fuel to the engine 3. 6 is a front fork, 7 is a front wheel, and 8 is a seat.

The fuel tank 4 has a tank body 10 having a flat upper surface. A pipe 11 is welded to the front top of the tank body 10, and an inner hole of the pipe 11 serves as a fuel supply port 12. Further, a cap 13 that opens and closes the fuel supply port 12 is provided.

The cap 13 has a cap body 15, a pivoting means 16 for pivotally supporting the cap body 15 on the upper surface of the tank body 10, and a locking means 17 for holding the closed posture of the cap body 15 with respect to the fuel supply port 12. ing.

The cap body 15 is a flat bowl-shaped sheet metal cover plate 1
8 and a circular base member 19 fitted in the cover plate 18.
And have. On the other hand, the pivot support means 16 is a support base 2 screwed to the upper surface of the tank body 10 with bolts 21 and 21.
2, the cap body 15 is pivotally supported on the support base 22 by a pivot shaft 23.

The locking means 17 includes a bolt 25,
A pair of engaging projections 26, 26 provided on the locking means 17 and an inner flange 27 formed on the fuel supply port 12 are detachably engaged with each other, and the cap body is screwed. 15 is held to close the fuel supply port 12 (shown by the solid line in the figure). The engagement protrusion 26 and the inner flange 2
The disengagement of 7 is achieved by inserting a key (not shown) into the key hole 28 provided in the lock means 17 and rotating the key (shown by a chain double-dashed line in FIG. 4). 15 is rotatable upward, and the fuel supply port 12 is opened (indicated by a chain double-dashed line in FIG. 2). 29
Is packing.

A breather device is provided in the fuel tank 4 having the above configuration.
Hereinafter, this device will be described.

A communication passage 31 is formed in the cap 13, one end of the communication passage 31 is opened in the tank body 10, and the other end is communicated with a canister device (not shown) via a communication pipe 32 and a control valve 33. . The control valve 33 is a check valve, and as shown in FIG. 1, it is provided in the middle of the communication pipe 32, and
Inside the tank body 10, the same as above is attached to the lower front part of the tank body 10.

Although not shown, the control valve 33 allows the fuel to flow into the communication passage 31 when the vehicle is in a sideways posture.
It is configured to automatically prevent the flow to the canister device through the communication pipe 32 and the communication pipe 32.

The communication passage 31 will be described in more detail.

A main passage 35 having an arcuate shape in a plan view is formed between the cover plate 18 and the circular base body 19, and one end of the main passage 35 is the first.
It opens into the tank body 10 via the communication path 36. A sponge 37 is fitted in the first communication path 36.

Further, the middle portion of the main passage 35 opens into the tank body 10 via the second communication passage 38. A check valve 39 is provided in the second communication path 38, and the check valve 39 has a ball 40 which is a valve body. And this check valve 3
9 allows only a flow from the main passage 35 into the tank body 10 when the fluid flows through the second communication passage 38. That is,
The check valve 39 prevents the fuel in the tank body 10 from flowing through the communication passage 31 and the communication pipe 32 toward the canister device.

The other end of the main passage 35 is opened above the support base 22 via the third communication passage 42. A fourth communication path 43 is formed on the support base 22, and a rubber packing 44 is interposed between the opening edges of the third communication path 42 and the fourth communication path 43 facing each other. The rubber packing 44 is attached to the support base 22 side, and when the cap body 15 is rotated upward, the communication between the third communication path 42 and the fourth communication path 43 is released.

The fourth communication passage 43 is connected to one end of the communication pipe 32 screwed to the tank body 10.

Next, the operation of the breather device having the above configuration will be described.

First, when the internal pressure of the fuel tank 4 becomes low, outside air is drawn into the fuel tank 4 through the communication pipe 32 and the communication passage 31 (shown by the arrow in the figure).

On the other hand, when the internal pressure of the fuel tank 4 becomes high, the fuel tank 4
The fuel gas inside flows in the opposite direction to the above and is guided to the canister device. Further, when the fuel tank 4 is filled with the fuel and the fuel flows into the communication passage 31 in a liquid state, the check valve 39 restricts the inflow of the fuel into the communication passage 31 (fourth (Indicated by a chain double-dashed line in the figure), and thus the flow to the canister device is restricted.

(Effect of the Invention) According to the present invention, in the case where the communication passage is formed in the cap provided on the front top portion of the tank main body and the communication passage is connected to the canister device through the communication pipe, Since a check valve was provided to prevent the fuel from flowing toward the canister device through the communication passage and the communication pipe, the fuel inside the tank body was Any attempt to flow to the canister device is reliably blocked by the check valve.

Therefore, the function of the canister device is not hindered even when the vehicle is in a horizontal position.

Further, since the check valve is provided inside the tank body, it is possible to prevent the check valve from touching the eyes of a third person in appearance.

Therefore, although the check valve is provided in order to prevent the fuel from flowing into the canister device, the appearance of the vehicle is kept in good appearance and the check valve is prevented from being stolen.

Further, as described above, the cap is provided on the front top portion of the tank body, the communication passage is formed in the cap, and the communication passage is connected to the canister device through the communication pipe, and the communication pipe is checked in the middle part. If a valve is provided, the check valve is attached to the lower front part of the tank body.

Therefore, since the cap and the check valve are both provided on the front side of the tank body and close to each other,
In the tank body, the communication pipe from the communication passage side formed in the cap to the check valve can be shortened.

Therefore, the communication pipe in the tank body is required to have sufficient strength and strong support in order to receive a load from the fuel, and the structure tends to be complicated. By shortening the length, there is an effect that the above configuration can be simplified.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a partial side sectional view of a front portion of a motorcycle, and FIG. 2 is a partial enlarged sectional view of FIG.
3 is a sectional view taken along the line III-III of FIG. 2, FIG. 4 is a sectional view taken along the line IV-IV of FIG. 2, and FIG. 5 is a sectional view taken along the line VV of FIG. 6 and 6 are views taken along the line VI-VI in FIG. 1 ... Motorcycle (vehicle), 4 ... Fuel tank, 10 ...
... tank body, 12 ... fuel supply port, 13 ... cap, 31 ... communication passage, 32 ... communication pipe, 33 ... control valve (check valve).

Claims (1)

[Claims] 1. A fuel supply port is formed at a front top portion of a tank body, and a cap is provided for opening and closing the fuel supply port. A communication passage is formed in the cap. One end side of the communication passage is the tank. In a fuel tank for a vehicle, which is open to the inside of the body and whose other end is connected to a canister device located outside the tank body through a communication pipe, the fuel in the tank body is connected to the communication passage and the communication pipe. A check valve is provided in the middle of the communicating pipe to prevent the flow of the check valve toward the canister device through, and the check valve is inside the tank body and the front lower portion of the tank body. A breather device for a fuel tank for a motorcycle, characterized in that it is attached to a fuel tank.