JPS59202986A - Mounting structure of rear arm in car such as shaft drive type motorcycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of mounting a rear arm that supports a rear wheel in, for example, a shaft drive type motorcycle.

In this type of shaft drive motorcycle, engine power is transmitted to the drive shaft in the rear arm via a bevel gear, but the front end of this rear arm is rotatably pivoted to the engine and the vehicle body. In addition, this front end pivot point and the output shaft, which is the output end of the engine power, are located offset in the longitudinal direction of the vehicle body, so it was necessary to provide a universal joint in the middle of the drive shaft. This has resulted in problems such as a complicated structure of the power transmission system and an increase in the number of parts.

The present invention was made based on these circumstances, and
The purpose of mounting the rear arm on vehicles such as shaft drive motorcycles is to provide a structure that does not require the conventional universal joint or even the pivot that supports the rear arm, making it simple, compact and lightweight. shall be.

That is, in order to achieve the above object, the present invention rotates the front end of the rear arm through which the drive shaft for driving the rear wheels is inserted, relative to the output shaft of the engine power located perpendicularly to the drive shaft. The output shaft is pivoted so as to be rotatable in the direction, and this output shaft is also used as the pivot shaft of the rear arm.

An embodiment of the present invention will be described below based on drawings in which the present invention is applied to a motorcycle.

1 in the figure is a Gresback Dane type vehicle frame,
A front fork 2 and a fuel tank 3 are attached to the front part of this body frame 1, and a seat 4 and a seat pack 5 are attached to the rear part. A four-stroke single-cylinder engine 6 is mounted approximately in the center of the vehicle body frame 1. The details of this engine 6 are shown in FIG. A flywheel magneto 10 is fixed to the left end of the shaft 9. The flywheel magnet 10 is of an outer rotor type, and the outer diameter 11 of the rotor 1 is smaller than the outer diameter t2 of the crank web 12. For this reason, a large space 13 is secured behind the rotor J, commensurate with the above-mentioned reduction in diameter. At the right end of the crankshaft 9 are a centrifugal clutch 14 and a centrifugal clutch 1.
A pair of transmission gears 15, 16 are attached, and these transmission gears 15, 16 are rotated integrally with the crankshaft 9 via the centrifugal clutch J4 when the centrifugal clutch J4 is engaged.

Also, one output shaft 12 is rotatably housed in the crankcase 7 parallel to the crankshaft 9.
This output shaft J7 is rotated in the direction of arrow A in conjunction with the crankshaft 9 by a constant-mesh type transmission gear train 18 that selectively meshes with the transmission gears 15, 16. The left end portion of the output shaft 17 passes through the crankcase 7 and is led out into a space 13 behind the rotor 1, and a bevel gear 19 is fixed to this led out portion. A front end portion of a rear arm 20 extending rearward is located in the space 13 portion. That is, the rear arm 20 has a hollow cylindrical arm body 2, and a gear case 22 fixed to the front end of the arm body 2 is located in the space 13. And this rear arm 20
A drive shaft 23 extending rearward and perpendicular to the output shaft 17 is inserted therein. The drive shaft 23 is divided into two in the axial direction into a front shaft 24 and a rear shaft 25.
4 is rotatably supported within the gear case 22 via a bearing 26, and is connected to the output shaft 17 within the gear case 22. That is, another bevel gear 27 that meshes with the bevel gear 19 on the output shaft 17 side is fixed to the front end of the front shaft 24), and these bevel gears 19.
27, the rotation of the output shaft 17 is transmitted to the front shaft 24 so that it is rotated in the direction of arrow B in FIG. The bevel gears 19 and 27 are housed in a gear case 22, and this gear case 22 is connected to the output shaft 17.
(Dth5- The front end of the rear arm 20 is rotatably supported by the output shaft 170 through the output end and the output shaft 170 of the crankcase 7 through bearings 28 and 28, respectively. The output shaft 17 is rotatably supported in the υ direction as a center of movement, and this output shaft 17 also serves as a pivot shaft for the rear arm 20.

The front shaft 24 and the rear shaft 25 are connected within the arm body 2) via a buffer mechanism 29 for overload prevention, as shown in FIG. When excessive torque is applied from the front shaft 240 to the rear shaft 25, the ring member 30 interposed between the cylindrical body 24m of the front shaft 240 and the rear shaft 25 moves toward the ridge shaft 25 against the biasing force of the spring 3. The spline engagement between the cylindrical body 24a and the ring member 30 is released, and power transmission to the front shaft 24 is cut off. Further, the rear shaft 25 passes through the rear arm 20 and is led out into a gear housing 32 provided at the rear end of the rear arm 20, and a bevel gear 6-33 is formed at this lead-out end. An axle 35 of the rear wheel 34 is rotatably supported in the gear housing 32 in the left-right direction, and a bevel gear 36 fixed to the end of the axle 35 on the rear arm 20 side is connected to the bevel gear 33 of the rear axle 25. They mesh together. Therefore, the rotation of the rear shaft 25 is transmitted to the wheel @35 via the bevel gears, 93, 36.

The gear housing 32 is suspended on the vehicle body frame 1 via a shock absorber (not shown).

According to such a configuration, the gear case 22 at the front end of the rear arm 20 is rotatably connected to the output shaft 17 that outputs engine power, and the rear arm 20 is connected to the output shaft 17.
Since the rear arm 20 also functions as a pivot shaft, a special bit shaft for supporting the rear arm 20 can be made unnecessary. Moreover, since the center of rotation of the rear arm 20 and the output shaft 17, which is the output end of the engine power, are located coaxially, there is no need to provide a special universal joint on the drive shaft 23 as in the conventional case. Combined with the ability to omit the pivot axis, the number of parts can be reduced, making it possible to achieve smaller size and lighter weight.

In addition, on the actual arm side, the outer diameter 11 of the rotor 1 constituting the flywheel magneto 0 is made smaller than the outer diameter t2 of the crank web 12, so that a wide space 13 is secured behind the rotor 1. Therefore, the end of the output shaft 17 is led out into this space 13, and the bevel gear 19°2 is inserted here.
7 and gear case 22 can be arranged, and limited space can be used effectively. In addition, the output shaft 17 can be arranged closer to the crankshaft 9, and the crankcase 7 can be made into a concrete structure.

In addition, the output shaft noa is connected to the rear wheel 3 as shown by arrow A in Figure 2.
4, the meshing portion between the bevel gear 19 of the output shaft 17 and the bevel gear 27 of the drive shaft 23 is rotated in the opposite direction to the rotating direction of the output shaft J1, that is, the rear arm 2
A reaction force is applied that pushes down the edge of 0. For this reason, the phenomenon of tail rise at the time of start, which is common with shaft drives, is alleviated, and the driving force of the rear wheels 34 can be transmitted favorably to the ground m1.

In the above-described embodiment, the rear wheel is cantilevered, but it may be supported between the left and right rear arms, and the vehicle according to the present invention is not limited to a motorcycle, but can also be a motorcycle with two rear wheels. According to the present invention, which has been described in detail in the above embodiments, the front end of the rear arm is rotatably connected to the output shaft that outputs engine power.
The output shaft also functions as a pin shaft for the rear arm,
Therefore, a special pivot shaft for supporting the rear arm can be omitted, and since the rotation center of the rear arm Q and the output shaft are located coaxially, there is a special pivot shaft on the drive shaft that extends rearward in relation to the output shaft. There is no need to provide a joint, so the number of parts can be reduced, and the structure is simple and has the advantage of being compact and lightweight.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show one embodiment of the present invention, in which FIG. 1 is a side view of a motorcycle, FIG. 2 is a sectional view, and FIG. 3 is a partially sectional side view. 9- 6...Engine, 2...Crankcase, 9...
Crankshaft, 17... Output shaft, 19.27... Bevel gear, 20... Rear arm, 22... Front end (gear case), 23... Drive shaft, 34... Rear wheel. Applicant's agent Patent attorney Takehiko Suzue-10- JP-A-59-202986 (4)

Claims (1)

[Claims] An output shaft that outputs engine power is provided in the crankcase parallel to the crankshaft, and a rear arm that supports the rear wheels and extends rearward drives the rear wheels along a direction perpendicular to the output shaft. Insert the drive shaft for
This drive shaft is driven by another bevel gear that meshes with the bevel gear provided on the output shaft, and these bevel gears are housed in the front end of the rear arm, and the front end of the rear arm is connected to the shaft of the output shaft. The structure of the rear arm of a vehicle such as a shaft drive motorcycle, which is characterized by being pivoted so that it can rotate in multiple directions.