JPH0378308B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a breather pipe mounting structure for a fuel tank.

The inside of a fuel tank provided in a motorcycle or the like is filled with fuel that has been gasified by volatilization. If this gasified fuel is released directly into the atmosphere from the breather hole, it will cause air pollution, so to prevent this, a breather pipe is installed inside the fuel tank, and the vent of the breather pipe is placed above the inside of the fuel tank. There is one in which the other end is connected to a canister outside the fuel tank, and the canister is connected to the intake system of the engine. The canister is generally a container filled with granular activated carbon, and has the function of adsorbing gasified fuel introduced from the breather pipe as described above.

However, since the breather pipe is installed inside the fuel tank, it is very difficult to process the breather pipe to install it. Moreover, the breather pipe attached to the bottom of the tank was sometimes deformed or damaged due to the effects of engine vibration.

Further, the fuel tank generally has an outer shell having an inverted U-shape in cross section, and is attached so as to straddle the upper part of the vehicle body frame from side to side. Therefore, the lower surface of the bottom plate of the tank is located at a deep position, considerably above the left and right edges, and therefore the breather pipe connector has to be installed at a deep position, making it difficult to connect evaporated fuel storage chambers such as canisters. It was very troublesome.

Further, as described above, since the outer shell has an inverted U-shaped cross section, the lower the vehicle body position is made, the smaller the fuel tank capacity tends to be. When such a breather pipe is provided in such a fuel tank, the capacity becomes smaller and smaller.

The purpose of the present invention is to solve the above-mentioned conventional problems and not only facilitate the installation work of a breather pipe, but also prevent the breather pipe from being deformed or damaged by engine vibration. ,
To provide a breather pipe mounting structure for a fuel tank for a motorcycle, which facilitates the work of mounting a canister to the end of a breather pipe opened at the lower surface of a tank bottom plate, and makes it possible to secure tank capacity at once.

In order to achieve the above object, the present invention mounts an engine 2 in the middle of a vehicle body frame, and provides a fuel tank 1 above the engine 2 so as to straddle the upper side of the vehicle body frame from side to side. It is composed of a combination of an upper outer plate 1a and a lower bottom plate 1b having an inverted U shape, and a recess 14 is formed at the rear of the upper surface of the bottom plate 1b so that the lower surface thereof protrudes downward. A coupling 10 for connecting a pipe is placed in the recess 14.
is inserted and fixed to the bottom of the recess, and the rear end of the breather pipe 5 is connected to the end of the connector 10 facing inside the tank, and the main body of the breather pipe 5 is inserted forward along the upper surface of the bottom plate 1b. and fixed to the bottom plate 1b via the stay 8, and the breather pipe 5
A separator 9 having a gas-liquid separation function is provided at the front end by bending the front end side of the connector upward, and the separator 9 faces near the fuel inlet provided on the outer plate 1a, and the other side is connected to the outer side of the tank of the connector 10. The fuel vapor storage chamber is connected to the end facing the fuel vapor storage chamber.

Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

FIG. 1 is a side view of a motorcycle having a breather pipe mounting structure according to the present invention. 1 is a fuel tank, and below this fuel tank 1, an engine 2, a carburetor 3, and a canister 4 are arranged. A breather pipe 5 is provided within the fuel tank 1, and the breather pipe 5 is connected to a canister 4 through an external pipe 6, and the canister 4 is further connected to the upstream side of the carburetor 3 through a pipe 7.

FIG. 2 is an exploded perspective view of the fuel tank 1, and FIG. 3 is a longitudinal sectional view of the same tank.
As shown in these figures, the fuel tank 1 consists of a combination of an upper outer plate 1a and a lower bottom plate 1b.
When both the upper and lower plates 1a and 1b are combined, an integral tank is constructed by seam welding the peripheries where they contact each other. A breather pipe 5 is arranged along the upper surface of the bottom plate 1b, and is fixed to the bottom plate 1b via a stay 8 attached to the breather pipe. The tip of the breather tube 5 is bent upward and opens near the fuel inlet provided at the upper front of the outer panel 1a to reduce the intrusion of fuel liquid into the breather tube, and to prevent gas and liquid from entering the breather tube. A separator 9 having a separation function is provided. Gasified fuel is introduced from this separator 9 into the breather pipe. Further, a recess 14 is provided on the rear side of the bottom plate 1b, a connector 10 is welded into the recess 14, and the tail end of the breather pipe 5 is attached to the connector 10.

Further, a screw hole 13 for connecting an external pipe is formed in the connector 10, and an external pipe 6 is connected to the screw hole 13 from the bottom side of the bottom plate 1b via a control valve 11 that is removably screwed into the screw hole 13. It has connection functions. This external pipe 6 is further connected to the canister 4
connected to. This control valve 11 is open when the vehicle is in a substantially vertical position as shown in FIG. The pipe 5 and the canister 4 are cut off.

FIG. 5 shows details of the separator 9 provided at the tip of the breather pipe 5. This separator 9 has a small hole 9a in the lower part, and a space 9b in the upper part thereof between the separator 9 and the upper end of the breather pipe 5. Therefore, even if gas and liquid enter from the small holes 9a at the same time, the liquid will be separated from the gas and returned to the outside of the separator 9.

6A and 6B show another embodiment of the separator 9, in which the booth 9b is formed by a small hole located on the opposite side of the small hole 9a. FIG. 7 shows a separator of still another embodiment, and the booth
The opening 9b is formed by an inclined gap opening at a position opposite to the small hole 9a. Moreover, in addition to the embodiment shown in FIG. 7, in FIGS. 8A and 8B, a shielding plate 9c is further provided outside the small hole 9a. Fig. 9 shows a separator 9 in which gas-liquid separation chambers are provided in two stages, and small holes 9a and 9a' are bored at the bottom of each chamber so as to shift their positions from each other. . Figure 10 shows the same configuration as Figure 9, including the position of the small hole 9a' and the booth 9.
This is a modified version of b. Each of the embodiments described above has a good gas-liquid separation function as in the case of FIG. 5.

Since the above-mentioned fuel tank consists of a combination of the outer plate 1a and the bottom plate 1b, the stays 8 are attached to the bottom plate 1b in advance.
The breather pipe 5 is fixed through the breather pipe 5.
Attach the tail end to the connector 10 welded to the bottom plate 1b, and then combine the upper and lower plates 1a and 1b and seam weld the outer circumferences to easily form a fuel tank with a breather pipe firmly installed inside. can be produced.

In addition, since the fuel tank is composed of a combination of an outer plate 1a and a bottom plate 1b, both of which have an inverted U-shaped cross section, the lower surface of the bottom plate is located deep above both the left and right edges, but the breather pipe is connected Since the connector 10 for use in the tank is attached to the bottom plate 1b by forming a recess 14, the lower surface side of the recess 14 is made to protrude significantly downward, thereby causing the tank outer end of the connector 10 to be attached to the bottom plate 1b. The work of attaching the canister 4 to the canister 4 can be facilitated.

Furthermore, by forming the recess 14 in the bottom plate 1b, the rigidity of the bottom plate 1a at the breather pipe connecting portion is increased, and the breather pipe 5 is prevented from being deformed or damaged due to the influence of engine vibration. be able to. Furthermore, since the recess 14 expands the tank capacity, even if the breather pipe 5 or the like is installed inside, it can contribute to securing the necessary tank capacity.

Furthermore, as in the above-described embodiment, the connector 10 having a threaded hole 13 and having the function of connecting an external pipe is provided at the tail end of the breather pipe 5, so that a connecting member (control valve 11, etc.) can be attached and detached. Can be screwed together.

Therefore, for destinations that do not require a canister, by replacing the connecting member with the plug 12, it is possible to share the same fuel tank for both destinations.

As described above, in the present invention, the fuel tank is constructed from a combination of an upper outer plate and a lower bottom plate, and the breather pipe is attached to the bottom plate side.
By attaching the breather pipe to the bottom plate and then assembling the outer plate to the bottom plate, it is possible to easily obtain a fuel tank with the breather pipe installed inside.

In addition, since both the outer plate and the bottom plate have an inverted U-shaped cross section, it is difficult to reach into the narrow space under the bottom plate from both edges, but the fixing part of the breather pipe connector Since a recess is formed in the bottom plate, the lower surface side of the bottom plate can be made to protrude significantly downward, making it easier to attach evaporative fuel storage chambers such as canisters to connectors that open deep in the lower surface of the bottom plate. It can be done. Furthermore, by forming the recess as described above, the rigidity of the bottom plate near the breather pipe fixing part is improved, and since the breather pipe is fixed to the bottom plate by the stay, these factors work together to make the breather pipe It can prevent deformation or damage due to vibration. Further, due to this recessed portion, a sufficient tank capacity can be ensured even though a breather pipe or the like is installed inside the tank.

Further, since the tip of the breather pipe is opened at a high position near the fuel inlet and a separator having a gas-liquid separation function is provided, it is possible to make it difficult for fuel liquid to enter the breather pipe.

[Brief explanation of drawings]

FIG. 1 is a side view of a motorcycle equipped with a structure according to the present invention, FIG. 2 is an exploded perspective view of a fuel tank in the motorcycle, FIG. 3 is a vertical sectional view of the fuel tank, and FIG. 4 5 is a longitudinal sectional view of the fuel tank in which the control valve is replaced with a plug, FIG. 5 is a longitudinal sectional view of the separator portion, and FIGS. 6A, B to 10 show other embodiments of the separator, respectively. FIG. 6B is a vertical sectional view showing FIG. 6A.
8B is a view taken along the - arrow of FIG. 8A, and FIG. 9B is a view taken along the - arrow of FIG. 9A. 1... Fuel tank, 1a... Outer plate, 1b... Bottom plate, 2... Engine, 5... Breather pipe, 6...
External pipe, 8...stay, 9...separator,
10... Connector, 13... Screw hole for external pipe connection.

Claims (1)

[Claims] 1. The engine 2 is mounted on the middle part of the vehicle body frame, and the fuel tank 1 is installed above it so as to straddle the upper side of the vehicle body frame from side to side. It is composed of a combination of an outer plate 1a and a lower bottom plate 1b, and a recess 14 is formed at the rear of the upper surface of the bottom plate 1b so that the lower surface thereof protrudes downward. The connector 10 is inserted and fixed to the bottom of the recess, the rear end of the breather pipe 5 is connected to the end of the connector 10 facing inside the tank, and the main body of the breather pipe 5 is attached to the upper surface of the bottom plate 1b. Along with extending forward, it is fixed to the bottom plate 1b via the stay 8,
Further, the front end side of the breather pipe 5 is bent upward to form a separator 9 having a gas-liquid separation function at the front end.
, the separator 9 faces near the fuel inlet provided on the outer plate 1a, and an evaporated fuel storage chamber is connected to the end of the connector 10 facing the outside of the tank. Breather pipe mounting structure for fuel tank.