JPH0121913Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a front fender structure for a motorcycle (including a tricycle).

BACKGROUND TECHNOLOGY An example of a system in which a wind guide passage is formed in the front fender of a motorcycle and the engine side including the rear radiator is forcedly cooled by the running wind introduced from the wind guide passage is 1980-
No. 109094 discloses a front fender in which an air guide passage is formed along the upper surface of the front fender.

In such a structure, it is conceivable that other members may interfere with the front fender from above, making it impossible to provide sufficient space. On the other hand, even if an air guiding passage can be formed, there are circumstances that force a straight duct structure with a substantially uniform passage cross section. Therefore, there is no significant change in the flow velocity of the introduced air at the inlet-side opening end and the outlet-side opening end of the passage, and a sufficient cooling effect on the body to be cooled on the engine side cannot necessarily be obtained.

Summary of the invention The present invention was made to solve the above-mentioned problems of the conventional structure, and its purpose is to provide a front fender structure for a motorcycle that enhances the cooling effect on the body to be cooled on the engine side.

To achieve this objective, in the front fender structure of the motorcycle of the present invention, a pair of air guide passages are provided along both sides of the front fender and bypassing the front fork, and at the front open end. In comparison, the width and opening cross-sectional area of the front fork are small.

Embodiment Hereinafter, a front fender structure for a motorcycle that is an embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, a pair of left and right front forks 3, 3 supporting the front wheels 2 of the vehicle body 1 are shown.
A front fender 4, which usually serves as a mudguard, is fixed between the front fenders 4 and 4. In this case, the front fender 4 is formed into a box shape consisting of a top plate and side plates so as to completely cover the upper part of the front wheel 2.

Such a front fender 4 is fixed to the front forks 3, 3 in such a way that they are inserted from both sides, and the side plates on both sides of the front fender 4 have a bulge and are gently curved, with the front fork insertion part being the apex. It draws a curve.

On the other hand, along both sides of the front fender 4, a pair of air guide passages (hereinafter simply referred to as ducts) 5,
5 is provided on the front fender 4 by integral molding or by combining separate structures. As is clear from FIG. 2, which is a plan cross-sectional view, the shape of the duct 5 is defined by the intermediate portion 5 from the front opening end 5a to the front fork 3.
Up to b, both the width and the cross-sectional area of the opening gradually become smaller, resulting in a narrower shape. That is, the width B at the front opening end 5a is reduced to the width b at the intermediate portion 5b, and the height in the vertical direction is also reduced.

Also, from the middle part 5b of the duct 5 to the rear opening end 5C
Up to this point, the cross-sectional area of the opening due to the width b is approximately uniform or gradually decreases slightly toward the rear opening end 5c.

The reason why the duct 5 is formed in this way is that if the traveling wind indicated by the arrow A is regarded as a hydrodynamic compressible fluid, the flow velocity of the introduced wind increases from the front opening end 5a to the middle part 5b. The fluid temperature theoretically decreases due to the increase in fluid pressure and the decrease in fluid pressure. Therefore, the cooling effect on the engine side including the rear radiator 6 is enhanced.

In addition, the width of the intermediate portion 5b of the front fork 3 is set to b, and the reason why the opening cross-sectional area is narrowed down in this portion is as follows:
This is because the ducts 5 and 5 further detour from the outside of the bulged portion, respectively, to minimize the vehicle body width W that expands further and reduce the running wind pressure resistance.

In addition, from the purpose of reducing the running wind pressure resistance, it is necessary to
It is preferable that the opening cross-sectional area is gradually increased toward c (indicated by the chain double-dashed line in the figure), and that the entire duct is formed in a gentle streamlined shape with the intermediate portion 5b as the apex.
Furthermore, if the cross-sectional area of the rear opening end 5c is increased and expanded, the cooling range for objects to be cooled, such as the radiator 6, can be expanded. However, in the case of the structure of the embodiment, the cross-sectional area of the rear opening end 5c is not made large enough, and the theoretical cooling system allows the traveling wind that is restricted at the intermediate portion 5b to be guided to the engine side while maintaining that state. In consideration of the balance between the effect and the duct shape which is close to the ideal for the above-mentioned traveling wind pressure resistance, the opening cross-sectional area in the intermediate portion 5b is made substantially uniform up to the rear opening end 5c.

Consideration of the invention As can be understood from the above, according to the front fender structure of the motorcycle of the present invention, since a pair of air guide passages are formed along both outer surfaces of the front fender, Compared to the conventional structure, the space on both sides of the front fender can be used more effectively, which increases the degree of freedom in design.It also suppresses the increase in wind pressure resistance due to the installation of air guide passages and provides an air cooling effect. This makes it possible to increase the cooling effect on the object to be cooled.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the front wheel and its surroundings of a motorcycle employing a front fender structure according to an embodiment of the present invention, and FIG. 2 is a plan cross-sectional view of the front wheel and its surroundings including a main part of the air guide passage. Explanation of symbols of main parts, 3...Front fork, 4...Front fender, 5...Air guide passage (duct), 5a...Front opening, 5b...Middle part, 5c...Rear opening end.

Claims (1)

[Scope of utility model registration request] A pair of air guide passages extend along both sides of the front fender and bypass each front fork, and the width and opening cross section of the front fork are smaller than the front opening ends of the air guide passages. A front fender structure for a motorcycle characterized in that the area is reduced.