JP2560156Y2 - Fuel tank cap - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank cap having a breather passage used for a fuel tank of a general-purpose engine or the like.

[0002]

2. Description of the Related Art A cap for a fuel tank of a general-purpose engine or the like is used to communicate between the inside of the fuel tank and the atmosphere.
An air passage called a breather passage is provided in the screw portion. Through this breather passage, the atmosphere flows into the tank as the fuel is consumed, and the air in the expanded tank flows out as the temperature rises, so that an appropriate amount of fuel is always supplied to the engine. ing.

However, in general, fuel tanks used in general-purpose engines have a small capacity of about 1 to 2.5 l and are often shallow, so that when the fuel tank vibrates violently and the fuel in the tank becomes wavy, May reach the inside of the cap. In this case, the fuel may adhere to the breather passage provided in the cap to prevent air from entering or exiting, or the attached fuel may leak out of the cap together with the air flowing out due to thermal expansion.

To prevent this, inside the cap,
Generally, a gasket provided with a vent for a breather passage is mounted.

[0005] Further, assuming that the gasket alone is not sufficient, a disk-shaped plate 47 is further provided below the gasket 46 of the fuel tank cap 41 in the example shown in FIG. The gasket 46 and the plate 47 are passed through a projection 45 integrally formed downward at the center of the inner surface of the cap main body 43, and have a structure in which the tip 45 a of the projection 45 is thermally welded to support the plate 47. Since the outer diameter of the plate 47 is smaller than the inner diameter of the fuel supply port 44 of the fuel tank 42, a gap 48 generated between the outermost peripheral portion of the plate 47 and the inner wall of the fuel supply port 44 is formed.
A breather passage is formed together with the vertical groove 43a provided in the screw portion 3 and the vent hole 46a provided in the gasket 46.

Another example of a fuel tank cap having a breather passage is disclosed in Japanese Utility Model Laid-Open Publication No. 61-108573.

[0007]

However, in the example shown in FIG. 3, although there is a plate, the fuel that undulates in the tank and scatters upward from the gap around the plate adheres to the hole of the gasket, and the fuel is removed from the tank. Often leaks out due to thermal expansion of the air, and cannot completely prevent fuel leakage.

Further, since the tips of the projections are heat-welded to support the plate, there is an inconvenience that a tool for welding and extra manufacturing time are required, and that the gasket and the plate cannot be replaced.

In view of the above, it is an object of the present invention to provide a fuel tank cap that prevents fuel leakage due to undulation and that allows easy replacement of gaskets and the like.

[0010]

In order to solve the above-mentioned problems, a fuel tank cap according to the present invention has a downward projection having a knob-like portion in a part thereof substantially integrally at the center of the gasket (integrally with the gasket). A cylindrical skirt having a part as an opening as a breather passage is integrally formed around the ventilation hole and the projection (also integrally with the gasket), and the plate is passed through the projection. It hung on the above-mentioned knob-like part, and was contacted with the lower end of the skirt.

A gap is provided between the gasket and the cap body, and a vertical groove is formed in the threaded portion of the cap body. The gap and the vertical groove are used as a breather passage following the opening of the skirt and the gasket vent. On the other hand, the outermost edge of the gasket supported by the threaded portion of the cap was made thinner than the portion between the fuel tank (such as a fuel filler) and the cap body.

[0012]

In the fuel tank cap of the present invention, since the lower end of the skirt of the gasket is in contact with the plate, the plate does not tilt and the position is always stable. Is always kept uniform and minimal. Therefore, most of the wavy fuel hits the plate and does not go up.

[0013] Even if a part of the fuel is scattered above the plate, the fuel does not reach the vent because the cylindrical skirt is provided around the vent at the upper part of the gasket. Since the skirt is partially provided with an opening, fuel leakage from the cap can be prevented while maintaining the breather function.

Further, since the protrusion protruding from the gasket is an elastic body integrally formed with the gasket, if the tip of the protrusion is pulled, the diameter of the protrusion on the protrusion becomes smaller than the inner diameter of the mounting hole of the plate, so that the plate has a protrusion. Can be mounted above the part. Then, if the projection is returned to the original position, the diameter of the nodular portion is also returned to the original position, and the plate does not fall. Therefore, mounting of the plate is easy, and parts such as the gasket and the plate can be replaced.

Further, in the cap according to the second aspect, a maze-shaped breather passage is formed by the gasket vent hole, the gap between the gasket and the cap body, and the vertical groove of the screw portion. More effective. Since the outermost edge of the gasket is thinner than the portion between the fuel tank and the cap body, a space is created between the edge of the gasket and the cap body. Therefore, even if a breather passage is formed by providing a vertical groove in the threaded portion, the gasket can easily secure the breather passage without blocking the vertical groove, and the gasket is the innermost part of the cap and the screw thread and the inner surface of the cap. The cap can be completely tightened because the gap between the cap and the space is reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel tank cap according to the present invention will be described below.

FIG. 1 is a sectional view of an embodiment of a fuel tank cap 1 according to the present invention, and FIGS. 2A and 2B are a plan view and a side view of a general-purpose engine 31 using the fuel tank cap 1 according to the present invention. Each figure is shown.

First, a general-purpose engine 31 shown in FIG. 2 is of a vertical axis type in which a crankshaft 32 is oriented in a vertical direction. The fuel tank 2 is mounted above the engine body 33, and the fuel tank cap 1 is used on the upper surface of the fuel tank 2.

As shown in FIG. 1, the fuel tank cap 1 includes a cap body 3, a gasket 11, and a disk-shaped plate 21.

The threaded portion 5 of the cap body 3 has a vertical groove 5a cut in a direction intersecting the thread as a breather passage, and the annular downwardly projecting portion 7 of the inner surface portion 9 has an annular groove 7a. There is a cutout 7b at each of the inside and outside of the annular groove 7a.

The gasket 11 is made of an elastic material such as nitrile rubber. The gasket 11 is provided with a notch 12a in the annular upward convex portion 12 on the upper surface 16, and the central downward convex portion 13 is formed.
The air hole 13a is opened. A cylindrical skirt 1 with a slit (opening) 14a in the lower part around the projection 13
4, downward projections 15 each having a bump-shaped portion 15 a at the center of the convex portion 13 are formed integrally with the gasket 11. The slit 14a is provided at a position as far as possible from the ventilation hole 13a.

A disk-shaped plate 21 having a lower edge 22 is mounted on the projection 15. A mounting hole is formed in the center of the plate 21, and the inner diameter (for example, 2.3 mm) is set smaller than the diameter (for example, 3.1 mm) of the bump 15 a of the projection 15. When attaching the plate 21,
The protrusion 15 is pulled to adjust the diameter of the bump 15a to the plate 2
1 is made smaller than the inner diameter. In this state, if the plate 21 is passed through the protrusion 15 and then the protrusion 15 is returned to its original position, the diameter of the knob-like portion 15a becomes larger than the inner diameter of the plate 21 again, so that the plate 21 can be supported. By setting the length of the skirt so that the lower end of the skirt 14 contacts the upper surface of the plate 21, the plate 21 does not tilt even if the fuel tank 2 vibrates violently.
The position stabilizes.

The outer diameter of the plate 21 is made slightly smaller than the inner diameter of the filler port 4 of the fuel tank 2 so that the gap 2
3 so that outside air can flow in. However, since the position of the plate 21 is stable, the gap 23 is always kept uniform and minimum over the entire range.

Therefore, in the fuel tank cap 1 having such a configuration, even if the fuel is ruffled by violent vibration, the gap 23 around the plate 21 is kept to a minimum, so that most of the fuel hits the plate and moves upward. Does not go. The fuel scattered above the plate is supplied to the vent hole 13a.
Skirt 14 formed integrally with the skirt 14 and cannot reach the vent hole 13a. If the vent 13
Even when the pressure reaches a, the breather passage leading to the atmosphere is bent and not straight like a maze, so that fuel leakage hardly occurs. That is, the vertical groove 5a of the cap body 3, the notch 7a, the notch 12a of the upper part 16 of the gasket 11, the ventilation hole 13a of the projection 13, the slit 14a of the skirt 14, and the gap 23 around the plate 21 function as a breather passage. In addition, fuel leakage can be prevented.

Further, when a filter (not shown) such as a sponge is put above the convex portion 13 of the gasket 11,
Even if there is fuel passing through the vent hole 13a, it is absorbed by the sponge, so that it is more effective in preventing fuel leakage.

The outermost edge 1 of the gasket 11
7 is thinner, a space 18 is formed between the edge 17 of the gasket 11 and the cap body 3, and even if a breather passage is formed by providing the vertical groove 5 a in the screw portion 5,
It becomes easy to secure the breather passage. In addition, since the gasket 11 is located at the innermost part of the cap body 3 and at the portion where the distance between the screw thread and the inner surface of the cap is reduced, the cap 1 can be completely tightened.

In the embodiment shown in FIG. 1, a vertical groove is provided in the threaded portion of the cap body as a breather passage. However, if the space above the gasket has a function of communicating with the atmosphere, a vent hole is provided in the cap body. You may. Further, the fuel tank cap of the present invention is not limited to a general-purpose engine, and can be applied to a fuel tank of a vehicle having a large vibration such as a buggy vehicle. In addition, it can be used for caps such as fuel gauges.

[0028]

By using the fuel tank cap having the above structure, it is possible to prevent fuel leakage from the breather passage and blockage of the breather passage. Moreover, manufacturing and
It is easy to assemble, the cost is low, and the gasket or plate can be replaced.

Further, in the fuel tank cap according to the second aspect, the breather passage is formed in a maze shape, which is particularly effective in preventing fuel leakage. In addition, it is possible to securely close the cap without blocking the breather passage. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a fuel tank cap according to the present invention.

FIG. 2A is a plan view of a general-purpose engine using the fuel tank cap according to the present invention. FIG. 1B is a side view of the general-purpose engine.

FIG. 3 is a longitudinal sectional view of a conventional fuel tank cap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel tank cap 2 Fuel tank 3 Cap body 4 Fuel tank filler 11 Gasket 14 Skirt 21 Plate

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Showa 50-34621 (JP, U) Japanese Utility Model Showa 54-97551 (JP, U) Japanese Utility Model Showa 49-102114 (JP, U) Japanese Utility Model Showa 51- 141781 (JP, U)

Claims (2)

(57) [Scope of request for utility model registration] 1. A gasket made of an elastic material having a ventilation hole near the center is mounted inside the cap body, and a plate for preventing fuel from splashing is provided below the gasket, and is attached to the fuel tank. A fuel tank cap in which a breather passage including the above-mentioned ventilation hole is formed between the inside of the tank and the atmosphere in a state where the gasket is formed. In addition, a cylindrical skirt partially having an opening as a breather passage is integrally formed around the ventilation hole and the projection, and the plate is
A fuel tank cap which is passed through the projection, is hung on the knob-like portion, and is in contact with the lower end of the skirt. 2. A gap is provided between the gasket and the cap body, and a vertical groove is formed in a threaded portion of the cap body, and the gap and the vertical groove are used as a breather passage following the opening of the skirt and the gasket vent. 2. The fuel tank cap according to claim 1, wherein the outermost edge of the gasket supported by the threaded portion of the cap is thinner than a portion sandwiched between the fuel tank and the cap body.