JPS6230616Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a transmission case device for a motorcycle.
In particular, the present invention relates to a transmission case device comprising an inner case half integrally provided at one end of an engine crankcase and an outer case half tightly connected to the inner case half at an outer ring joint surface.

Conventionally, in this type of device, the inner case half and the outer case half are joined together by bolts at the outer ring joint surface, but the transmission case extends from the side of the engine to the side of the rear wheel. Because of its long length, the central part of the transmission case resonates or resonates due to the vibrations of the engine, drive transmission mechanism, etc. during operation.
It had the disadvantage of inducing noise.

Therefore, an object of the present invention is to provide a transmission case device for a motorcycle that reduces the resonance of the case and suppresses the noise generated due to this resonance.

In order to achieve this objective, the transmission case device for a motorcycle according to the present invention includes an inner case half and an outer case half that are tightly connected at the outer ring joint surface.
Furthermore, the rigidity is increased by tightly connecting them to each other at the intermediate portion in the vertical direction.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of a motorcycle according to the present invention, FIG. 2 is a sectional view showing an embodiment of the present invention, and FIG. 3 is a side view with most of the outer case half removed.
In Figure 1, 1 is a frame, 2 is a front fork, 3 is a front wheel, 4 is a handle, 5 is a seat,
Reference numeral 6 indicates a rear wheel, and a step floor 7 is arranged between the front wheel 3 and the rear wheel 6, and a leg shield 8 is provided in front of the step floor 7, and a rear body 9 is provided in continuity with the step floor 7 at the rear. Further, 10 is an engine, 11 is a swing type power unit whose front part is pivotally connected to the frame via a link (not shown), and whose rear part is pivoted to the frame via a shock absorber 12. It includes a transmission case 13 extending from the rear wheel 6 to the sides of the rear wheel 6. A hook shaft 14 projects from the transmission case 13 to the side of the vehicle body, and is connected to an end portion of the hook shaft 14 through a hook 15.
An air cleaner case 16 is arranged above the power unit 11.

In FIGS. 2 and 3, the transmission case 13 has an inner case half 13a formed integrally with the crankcase 17 of the engine 10, and is connected to the inner case half 13a by bolting at the outer ring joint surface. The outer case half 13b supports the axle 18 of the rear wheel 6 at its rear end. Transmission case 13
The input shaft 19 in front of the axle 18 and both axles 1
The reduction gear mechanism 20 between 8 and 19 and the input shaft 19
A drive transmission mechanism 25 consisting of an upper pulley 21, a pulley 23 on the output shaft 22 of the engine 10, and a V-belt 24 installed between both pulleys 21 and 23 is installed inside, and constitutes the power unit 11 as a whole. are doing.

Inner case half 13a and outer case half 13b
An idle shaft 27 that rotatably and slidably supports an idle gear 26 is provided between the engine shaft 14 and the output shaft 22 of the engine 10 in the vertically intermediate portion of the engine 10. body 13
a, 13b, and further tightened and fixed by bolts 28, 28 from the outside of each case half 13a, 13b. Further, the inner case half 13a has one end of a return spring 29 that biases the kick shaft 14 in one direction so as to be located in the vertically intermediate portion thereof and between the push shaft 14 and the input shaft 19. The abutting stopper plate tightening tap 30 is integrally molded, and the outer case half 13b is integrally molded with a protrusion 31 that is coaxial with the tightening tap 30 and whose tip abuts. 31 is tightened and fixed to the tightening tap 30 by a bolt 32. As a result, the inner case half 13a and the outer case half 13b are
They are fastened to each other at the outer ring joint surface, and are also fastened to each other at the vertically intermediate portion. According to this, it is possible to increase the rigidity of the transmission case 13 without increasing its wall thickness, and there is no need to create a new tap position by using existing members, so the resonance of the case can be reduced with light weight and low cost. And the noise generated due to it can be suppressed.

Note that a packing 33 is interposed between the outer ring joint surfaces of each of the case halves 13a and 13b and between the tightening tap 30 and the protrusion 31. Further, a transmission cover 34 is provided between the case halves 13a and 13b at the rear of the transmission case 13, and covers the reduction gear mechanism 20 between the axle 18 and the input shaft 19 in a fluid-tight manner. It is also arranged between the joint surfaces of the outer case half 13b and the mission cover 34.

As described above, according to the present invention, the inner case half and the outer case half are fastened together at the outer ring joint surface, and the kit is further supported at the vertical intermediate portion of the two case halves. Since they are tightly connected to each other at at least one location near the shaft, sufficient rigidity can be obtained for the case near the shaft, and the rigidity of the entire case can be increased without increasing the case wall thickness, making it lightweight. Moreover, the resonance of the case can be reduced at low cost, and the noise generated due to this resonance can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a side view of a motorcycle according to the present invention, FIG. 2 is a sectional view showing an embodiment of the present invention, and FIG. 3 is a side view with most of the outer case half removed. Explanation of symbols of main parts, 1...Frame, 7...
...Step floor, 8...Leg shield, 10
...Engine, 11...Power unit, 13...
...Transmission case, 13a...Inner case half, 13
b... Outer case half, 17... Crank case, 18... Axle, 25... Drive transmission mechanism, 27
...Idle shaft, 30...Tightening tap, 31...
protrusion.

Claims (1)

[Scope of utility model registration request] Consisting of an inner case half integrally formed with the engine crankcase, and an outer case half opposed to the inner case half, the case is supported by the front and rear ends of the inner case half, respectively. A transmission case device for a motorcycle, which is equipped with a drive transmission mechanism for transmitting power between an output shaft of an engine and an axle, wherein the inner case half and the outer case half are fastened together at their outer ring joint surfaces. A kick shaft passing through the outer case half at an intermediate portion in the longitudinal direction is supported at an intermediate portion in the vertical direction of the inner case half, and the inner case half is supported at at least one location near the stiff shaft. A transmission case device for a motorcycle, characterized in that the outer case half and the outer case half are tightly coupled to each other.