JPH03235773A - Rear fender device for motorcycle - Google Patents

Abstract

PURPOSE:To prevent collision of rain water and air drawn in by a rear wheel with a muffler disposed below a rear arm and to prevent lowering of engine performance by disposing a rear fender, with which a rear wheel is covered, throughout a range from a position above the rear arm to a position therebelow. CONSTITUTION:In a motorcycle 1, a rear wheel 10 is supported to a rear arm bracket 5 through a rear arm 9. An engine 13 is mounted between a main frame 3 and the rear arm bracket 5, and an exhaust pipe from the engine 13 is connected to mufflers 14 and 15 on both sides and silencers 16 and 17. In this case, a rear fender 19 is extended from a position above the rear arm 9 to a position therebelow in a manner to cover the rear wheel 10 therewith, and mounted on the rear arm 9. Collision of rain water and air drawn in by the rear wheel 10 with the muffler 14 is prevented by means of the rear fender 19. This constitution prevents lowering of performance of the engine 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rear fender device for a motorcycle equipped with a two-stroke engine.

[Prior Art] Motorcycles are provided with a rear fender to protect the rear wheel from rainwater, mud, etc., but conventionally, the rear fender is attached to the top of the rear arm that supports the rear wheel, and the rear fender is attached to the front of the motorcycle. A method is known in which cooling air from a radiator located in the rear fender flows smoothly through the upper part of the rear fender.

[Problem to be solved by the invention] By the way, in a motorcycle equipped with a two-stroke engine, the pressure wave of exhaust gas discharged from the exhaust port of the engine is reversed in the expansion chamber of the muffler, and thereby unburned air-fuel mixture is By returning the fuel to the cylinder, power and fuel efficiency are improved. The length, capacity, etc. of this muffler are designed to optimize engine characteristics.

However, when the above-mentioned conventional rear fender is adopted for a motorcycle equipped with a two-stroke engine, the rear fender is placed only above the rear arm, so rain water, wind, etc. drawn in by the rear wheel may collide with the muffler. There is. As a result, the muffler is cooled and the pressure wave velocity (equal to the speed of sound) of the exhaust gas decreases, which changes the time it takes for the unburned air-fuel mixture to return to the cylinder, causing a problem in which engine performance deteriorates. .

The present invention solves the above-mentioned problem, and can prevent deterioration of engine performance by preventing rain water, wind, etc. caught in the rear wheels from colliding with the muffler in a motorcycle equipped with a two-stroke engine. The purpose is to provide a rear fender device.

[Means for Solving the Problems] To this end, the motorcycle rear fender device of the present invention has the following features:
In a motorcycle in which the muffler 14 of the two-stroke engine 13 is disposed below the rear arm 9 that supports the rear wheel 10, a rear fender 19 fixed to the rear arm and covering the rear wheel is arranged downward from above the rear arm. It will be arranged by.

Features.

Note that the numbers added to the above configurations are for comparison with the drawings, and the configurations of the present invention are not limited thereby.

[Function] In the present invention, as shown in FIGS. 1 and 2, for example, the rear fender 19 extends downward from the upper part of the rear arm 9 so as to cover the rear wheel 10, and the rear fender 19 extends downward from the upper part of the rear arm 9 so as to prevent rainwater that is drawn in by the rear wheel.
The muffler 14 is arranged to prevent wind from colliding with the muffler 14.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an overall side view of a motorcycle according to the present invention. The motorcycle 1 is composed of a head pipe 2, a pair of left and right main frames 3, a seat rail 4, and a rear arm bracket 5. A front fork 6 is rotatably supported, and a front wheel 7 is provided at the bottom thereof.

Further, a rear wheel 10 is supported on the rear arm bracket 5 via a rear arm 9, while a fuel tank 11 is provided above the main frame 3, and a seat 12 is provided on the seat rail 4. A two-stroke engine 13 is mounted and fixed between the main frame 3 and the rear arm bracket 5, and the exhaust pipe from this engine 13 is connected to left and right mufflers 14, 15 and a silencer 16.
．． 17. 19 is a rear fender according to the present invention.

FIG. 1 and FIG. 2 show one of the rear fender devices of the present invention.
An example is shown in which Fig. 1 is a side view, Fig. 2 is a plan view, and Fig. 4 is a side view.
The figure shows a side view of the right rear arm, and FIG. 5 is a sectional view taken along the line ■-■ in FIG. 4.

As shown in FIG. 1, the rear arm 9 on the left side in the direction of travel has a substantially trapezoidal shape when viewed from the side, and the rear arm 9 on the right side
As shown in FIG. 4, it has a substantially V-shaped shape when viewed from the side, and is connected to the connecting shaft 9a at the front part of the left and right rear arms 9.9.
A cross member 9b is fixed between the left and right rear arms 9.9 up to the vicinity of the rear wheel 10. The rear fender 19 extends downward from the upper part of the rear arm 9 so as to cover the rear wheel 10, and the muffler 1
4, so that it does not collide with the mounting piece 19a1113.
b is attached to the cross member 9b of the rear arm 8.

As shown in FIG. 3, the right muffler 15 is located closer to the rear wheel than the left muffler 14 due to space constraints. As a result, the muffler 15 protrudes to the outside of the right rear arm 9, creating a problem in that a large bank angle cannot be obtained. In order to solve this problem, as shown in FIGS. 4 and 5, the shape of the right rear arm 9 is made into a substantially V-shape, and a notch 9c is formed by cutting diagonally around the bent part of the V-shape. Then, the notch 9c is covered with a plate member, and the muffler 15 is placed therein.

FIG. 6 is a side view showing the other side of the structure of the right rear arm, and FIG. 7 is a sectional view taken along the line ■-■ in FIG. In addition, the left and right rear arms 9.9 are shown in the figure.

In this example, a notch A1B is formed in the rear arm 9 and its cross member 9b, and the notch has a substantially trapezoidal shape, in which the muffler 15 is disposed.

Next, the support structure for the rear arm 9 will be explained with reference to FIGS. 8 and 9. FIG. 8 is a sectional view showing the support structure of the rear arm, and FIGS. 9(a) and 9(b) are a plan view and a sectional view of the boss.

A pivot shaft 21 is located between the left and right rear arm brackets 5.5.
is fixed. An adjustment boss 22, a flanged collar 23, and a collar 24 are fitted to the outer periphery of the pivot shaft 21.
The rear arm 9 is rotatably supported via a bearing 25. As shown in FIG. 9, the adjustment boss 22 has an octagonal outer periphery and is formed so that the insertion hole 22a is located eccentrically. As a result, the pivot shaft 21 can be fixed to the rear arm bracket 5 at various eccentric positions, and the tension of the rear wheel drive chain can be made variable. This is because in a motorcycle in which the muffler part of a two-stroke engine is disposed below a rear arm that supports the rear wheel, a rear fender that is fixed to the rear arm and covers the rear wheel is disposed from above to below the rear arm. It is possible to prevent rainwater, wind, etc. caught in by the rear wheels from colliding with the muffler, thereby preventing deterioration in engine performance.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 show one of the rear fender devices of the present invention.
An example is shown in which Fig. 1 is a side view, Fig. 2 is a plan view, and Fig. 3 is a side view.
4 is a side view showing an example of the structure of the rear arm, FIG. 5 is a sectional view taken along the line ■-■ in FIG. 4, and FIG. A side view showing the other side of the structure of the rear arm, FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6, FIG. 8 is a sectional view showing the support structure of the rear arm, and FIGS. ) are a plan view and a sectional view of the boss. 9...Rear arm, 10...Rear wheel, 13...2-stroke engine, 14...Muffler 19...Rear fender.

Claims (1)

[Claims] (1) In a motorcycle in which the muffler part of the two-stroke engine is disposed below the rear arm that supports the rear wheel,
A rear fender device for a motorcycle, characterized in that a rear fender fixed to the rear arm and covering a rear wheel is disposed from above to below the rear arm.