JPS6243909Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention is a breather installed at the rear upper end of the fuel tank in so-called underbone type motorcycles, tricycles, and other vehicles in which the frame itself is used as a fuel tank. Regarding.

Prior art: A central part that supports the engine, a front part that extends forward from the central part and which has a head pipe fixed to its front end that pivotally supports the front forks, and a front part that extends rearward from the central part and which stands up and has a head pipe fixed to its front end. In a vehicle such as a motorcycle, the frame is integrally formed with a hollow member and has a rear part that supports the seat, and a fuel filler port is provided on the upper side near both ends to store fuel within the frame. In order to fill the rear part, which rises rearward, with fuel when refueling, a breather must be provided at the upper end of the rear part. If this breather is just a hole, there is a risk of fuel leaking from the rear breather when the frame is fully filled with fuel, when the rear is lowered on a climbing plate, or when sudden acceleration is performed. Therefore, in the past, the rear breather was equipped with a valve that opened when pushed by hand, and the breather was normally closed, but when refueling, the breather valve was opened by pushing by hand. However, with conventional breathers like this, it is cumbersome as it is necessary to operate the breather valve each time refueling.
There was a drawback that when the tank was filled with fuel, the fuel leaked from the breather and stained the hands.

Purpose of the Invention The present invention eliminates the drawbacks of conventional products by providing a breather at the rear upper end of the frame of this type of vehicle with a valve that automatically closes when the oil level reaches the breather.

Structure of the invention The present invention provides a cylindrical breather body that is integrally formed with a small-diameter upper part, a medium-diameter central part, and a large-diameter lower part in this type of vehicle, and the central part and the lower part of the breather body The upper part of the small diameter is passed through a cap that closes the upper end of the rear part of the frame so that the breather main body is supported by the cap, and the lower part has the inside and the A lower opening is provided that communicates with the inside of the frame, a float is provided within the lower part to be movable in the vertical direction, and a stopper is fixed to the lower end of the lower part to prevent the float from coming off downward. is provided with a ball supported by the float so as to be movable in the vertical direction, and a center opening is provided on the side surface of the upper part of the center part to communicate the inside of the ball with the inside of the frame, and inside the upper part there is a connection between the center part and the outside air. When the ball is lowered, the inside of the frame is communicated with the atmosphere through the breather passage, and when the ball is pushed up by the float, the ball is in contact with the atmosphere. The above object is achieved by a breather device for a fuel tank, which is pressed against an annular stepped portion between the center portion and the upper portion to cut off communication between the inside of the frame and the breather passage. .

Effects of the invention In this invention, when refueling, the ball remains down until the oil level reaches the float, so the air inside the frame escapes through the breather passage, and when the fuel is full, the oil level reaches the float. When it reaches the point, the ball is pushed up, cutting off the communication between the inside of the frame and the outside air. Therefore, the present invention performs the function of a breather during refueling without requiring any operations, and when the fuel is full, it automatically closes to prevent fuel leakage, and also prevents fuel from leaking even when going uphill or accelerating suddenly. There's no fear.

Embodiment FIGS. 1 and 2 show an embodiment of the invention.
The frame 10 of a so-called underbone type motorcycle is formed of one pipe.
A fuel filler port 12 is provided on the upper side of the front portion 10b of the frame 10 to store fuel within the frame 10. A breather 20 is provided passing through the center of a cap 26 that closes the upper end of the rear part 10c of the frame 10, and a float 23 and a ball supported by the upper end thereof are provided in the breather body 21 of the breather 20 so as to be movable in the vertical direction. Normally, both the float 23 and the ball 24 are lowered by their own weight, but when the fuel level rises, the float 23 rises and pushes the ball 24 up against the annular stepped portion 21d, thereby blocking the breather passage 20a. .

The frame 10 is integrally bent and formed from a single pipe, and consists of a central part 10a, a front part 10b extending forward and standing up from the central part 10a, and a rear part 10c extending rearward and standing up. Central part 1 of frame 10
An engine support plate 13 is welded to 0a, and supports the engine 1 via a support shaft 1a. engine 1
A rear wheel 4 is provided at the rear end of the power transmission case 2, which is integral with the engine 1, and the unit consisting of the engine 1, the power transmission case 2, and the rear wheel 4 is attached to the frame 10 by a support shaft 1a and a cushion unit 3. A head pipe 11 is installed at the front end of the front part 10b of the frame 10, and a fuel filler port 12 is installed at the upper side near the front end.
to weld. A front fork 5 that supports a front wheel 6, a front fender 7, and a handlebar 8 is pivotally supported on the head pipe 11. A bracket 14 for pivotally supporting the seat 9 is welded to the front side of the upper end of the rear part 10c of the frame 10, and a subframe 15 is welded to the rear side.
to fix. The upper end of the rear portion 10c is closed by welding a cap 26 that supports a breather 20, which will be described later. As shown in FIG. 2, the center of the cap 26 is narrowed inward into a cylindrical shape to provide a hole 26a.
A cylindrical guide 2 toward the inside of the frame 10
Weld 7. A notch hole 27a is provided in the welded part of the upper part of the guide 27, and a constricted part 27b is provided at the lower end of the notch hole 27a.
will be established. The inside of the frame 10 serves as a fuel tank for storing fuel, and has a fuel filler port 12 and a cap 2.
6 central hole 26a and two oil feed ports 17, 18 to the engine 1 provided on the lower side of the central part 10a.
Oil-tight except for (main and reserve).

The breather 20 includes a breather body 21 and a stopper 2.
2. Consists of float 23, ball 24, hole 26
cap 26 via a rubber stopper 25 glued to a.
most of which is located inside the guide 27. The breather main body 21 has a cylindrical shape with a diameter that changes in three stages: an upper part 21a with a small diameter and a central part 2 with a medium diameter.
1b and a large-diameter lower portion 21c, which are integrally molded from oil-resistant synthetic resin such as nylon. A hollow float 23 made of polyethylene or the like is provided inside the large diameter lower part 21c so as to be movable in the vertical direction, and is prevented from coming off downward by a stopper 22 adhesively fixed to the lower end of the lower part 21c. A ball 24 made of nylon or the like is provided within the medium-diameter central portion 21b so as to be movable in the vertical direction, and is supported by a protrusion 23a at the upper end of the float 23. A central opening 21e is provided on the side surface of the upper half of the central part 21b of the breather main body 21, which communicates the inside with the inside of the frame 10, and thus the inside of the frame 10 is cut out with a cutout hole 27a, and the central opening 2
1e, inside the middle diameter center part 21b, the small diameter upper part 21
It communicates with the atmosphere through a breather passage 20a inside a. The lower part 21c of the breather main body 21 has a lower opening 21 that communicates the inside thereof with the inside of the frame 10.
f, 22a are provided, and when the oil level of the fuel rises, the fuel enters the lower part 21c, and its buoyancy causes the float 2
Make it join 3. The breather 20 is installed by penetrating the small-diameter upper part 21a of the breather body 21 into the hole at the center of the rubber plug 25, and then inserting the rubber plug 25 into the hole 26a at the center of the cap 26 to support it. The portion 21b and the lower portion 21c are positioned within the rear portion 10c of the frame 10.

When the fuel in the frame 10 is low, the float 23 does not receive buoyancy due to the fuel, and the float 23
3.Both balls 24 have fallen due to their own weight, and the second
It is in the state shown in the figure. In this state, if fuel is injected from the fuel filler port 12, the rear part 1 of the frame 10
The air inside 0c is released through the notch hole 27a and the central opening 2.
1e, inside the central part 21b, is released into the atmosphere through the breather passage 20a, and is released into the atmosphere at the rear part 1 of the frame 10.
The oil level in 0c rises almost in the same way as the oil level in the front portion 10b. When the oil level rises and reaches the level of the float 23, the fuel enters the lower part 21c of the breather body 21 through the lower openings 21f and 22a, and the float 23 rises due to its buoyancy, pushing up the ball 24 by the protrusion 23a. The ball 24 is pushed up and the center part 21b and upper part 21a of the breather main body 21
When it comes into contact with the inclined annular step portion 21d between the center portions 21b, the communication between the inside of the center portion 21b and the breather passage 20a is cut off, and the communication between the inside of the frame 10 and the atmosphere is automatically cut off. Therefore, even if more fuel is supplied, there is no risk of fuel leaking from the breather passage 20a. Furthermore, even if the rear breather passage 20a goes down on an uphill slope and becomes below the oil level, or if fuel is biased towards the rear due to sudden acceleration and the rear oil level rises, buoyancy acts on the float 23 and the breather The passage 20a is cut off to prevent fuel leakage.

In the above embodiment, the float 23 is a molded product with an open bottom surface, but it may be a hollow product made by blow molding or the like, or it may be made of foamed resin. Further, although lower openings are provided in the lower part 21c and the stopper 22 (21f and 22a, respectively) for communicating the inside of the lower part 21c and the inside of the frame 10, only one of them may be provided.

Effects of Examples In the above examples, the oil level floats 23 during refueling.
Until the oil level reaches the level of the float 23, the air in the rear part 10c of the frame 10 escapes through the breather passage 20a and functions as a breather.When the oil level rises and reaches the level of the float 23, the ball 24 is pushed up by its buoyancy Since the breather passage 20a is automatically closed, fuel will not leak from the breather even when the fuel is full. Similarly, even if the oil level reaches the breather when going uphill or accelerating suddenly, fuel will not leak.

In the embodiment, the hole 26a in the center of the cap 26
The inner diameter of the breather body 21 is larger than the large diameter of the breather body 21, and the breather body 21 is connected to the cap 26 by the rubber plug 25.
Breather 2 for frame 10
0 is easy to attach and detach. Furthermore, since the breather 20 is positioned within the cylindrical guide 27 that extends into the hole 26a and has a constricted portion 27a at the lower end, even if the breather 20 accidentally falls downward, it will remain in the guide 27 and be recovered. is easy.

[Brief explanation of the drawing]

FIG. 1 is a side view of a motorcycle equipped with this invention, and FIG. 2 is a sectional view showing a breather and its mounting structure. Explanation of symbols, 1...Engine, 5...Front fork, 9...Seat, 10...Frame, 1
0a...center, 10b...front, 10c...rear, 11...head pipe, 12...fuel filler port, 2
0... Breather, 20a... Breather passage, 21
... Breather body, 21a ... Upper part of small diameter, 21
b...Central part of medium diameter, 21c...Lower part of large diameter, 2
1d...Annular stepped portion, 21e...Central opening, 21
f, 22a... lower opening, 22... stopper, 2
3...Float, 24...Ball, 26...Cap.

Claims (1)

[Scope of utility model registration request] A central part that supports the engine, a front part that extends forward from the central part and has a head pipe fixed to its front end that pivotally supports the front fork, and a front part that extends rearward from the central part and stands up and has a seat at its upper end. In a vehicle such as a motorcycle, the frame is integrally formed with a hollow member and has a rear part supporting the front end, and a fuel filler port is provided on the upper side near the front end to store fuel within the frame. A cylindrical breather main body consisting of an upper part, a middle diameter central part, and a large diameter lower part is integrally molded, and the small diameter is made such that the central part and the lower part of the breather main body are located within the rear part of the frame. The upper part is passed through a cap that closes the upper end of the rear part of the frame, and the breather main body is supported by the cap,
The lower part is provided with a lower opening that communicates with the inside of the frame, and a float is provided in the lower part so as to be movable in the vertical direction, and a stopper is provided at the lower end of the lower part to prevent the float from coming off downward. A ball supported by the float is provided in the center portion so as to be movable in the vertical direction, and a center opening is provided in the upper side of the center portion to communicate the inside of the center portion with the inside of the frame. A breather passage is formed inside the frame to communicate the central part with the outside air, and when the ball is lowered, the inside of the frame is communicated with the atmosphere through the breather passage, and the ball is pushed up by the float. 2. A breather device for a fuel tank, characterized in that when the ball is in a closed state, the ball is pressed against an annular stepped portion between the center portion and the upper portion, thereby cutting off communication between the inside of the frame and the breather passage.