JPH0739743Y2 - Rear wheel support device for unit swing engine of motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Use) The present invention relates to a rear wheel support device for a unit swing engine of a motorcycle such as a scooter.

(Prior Art) Many motorcycles use a unit swing type engine, as represented by a scooter, which is integrally suspended with a rear wheel and vertically oscillated so as to be vertically suspended. That is, a swing case extending from one side of the engine crankcase to the rear is continuously provided, a rear wheel is pivotally supported and integrated at a rear portion of the engine crankcase, and a front end portion is pivotally supported on the frame and a rear portion is connected to the frame by a rear swing unit. In the swing case, the power transmission system from the crankshaft to the rear axle is housed.

In the power transmission system, a belt (chain) transmission mechanism is generally arranged as a primary reduction from the crankshaft to the intermediate shaft, and a gear transmission mechanism is arranged as a secondary reduction from the intermediate shaft to the rear axle. An internal expansion type brake is used as the braking device.

However, in an off-road type motorcycle equipped with this type of unit swing type engine, the rear wheels may float up while traveling on rough terrain or wasteland, in which case the rear wheels become unloaded. When the rotation speed increases and the next touchdown, abnormally large force may be applied to the rear axle and damage the rear axle and the reduction gear. That is, in a general motorcycle, even if a similar shock is applied, the chain and the chain tensioner have a buffering effect, but in the unit swing type engine, since the reduction gear is directly incorporated on the rear axle, the primary conduction This is because shock torque is applied to the rear axle and reduction gear before reaching the belt and chain parts.

(Problems to be Solved by the Invention) As described above, in the unit swing type engine of a motorcycle, the rear axle or the reduction gear may be damaged when the rear wheels are lifted and come into contact with the ground when traveling on rough terrain or the like. In view of the above problem, the present invention has a damper member interposed between the rear wheel and the rear axle to reduce the shock generated in the rear axle due to a sudden rotation fluctuation of the rear wheel and prevent a damage accident. An object of the present invention is to provide a rear wheel support device for a unit swing type engine of a two-wheeled vehicle.

[Constitution of device]

(Means for Solving the Problems) In order to achieve the above-mentioned object, a rear wheel pivotal support device in a unit swing type engine of a motorcycle according to the present invention integrally includes a swing case extending rearward on one side of a crankcase. A rear wheel support device for a unit swing type engine of a motorcycle, in which a rear wheel is rotatably supported in the rear part and the swing case is vertically oscillatably suspended at a lower rear part of a vehicle body, in a swing case. The brake drum integrally with the rear wheels is rotatably supported on the rear axle protruding outward on the same side as the crankcase of, and the drive disk facing the outer surface of the side plate of the brake drum is fixed to the rear axle so as to rotate integrally. Equipped with a rubber damper that cushions the transmission of rotational torque between the brake drum side plate and the drive disc, and connects them in the rotational direction. However, the projecting tip of the rear axle is rotatably supported by the free end of a swing arm extending rearward from the other side of the crankcase.

(Operation) With this configuration, the rubber damper absorbs a shock applied to the rear axle when the rear wheels are lifted up and grounded during traveling, and the rear axle and the reduction gear are prevented from being damaged. Since a rubber damper is used, hardness, shape, etc. can be freely set, and a wide range of damper characteristics can be obtained. Even during sudden acceleration / deceleration while driving, the rider's comfort is improved by the damper action.

Further, the rear axle is stably swingably supported by a swing case extending rearward from one side of the crankcase and a swing arm extending rearward from the other side of the crankcase, while a rubber damper cushions a shock applied to the rear axle. Thus, the strength of the rear axle and the reduction gear can be reduced, the cost can be reduced, and the displacement of the brake drum in the thrust direction can be suppressed by causing the rubber damper to act in the thrust direction as well.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional plan view of the unit swing type engine taken along the arrow BB in FIG. As an overall configuration, the swing case 3 is extended from one side of the crankcase 2 of the engine unit 1 to the rear side, and the rear wheel 4 is pivotally supported on the rear part of the swing case 3, whereby the engine unit and the rear wheel are integrally formed. As in the scooter shown in FIG. 3, the front end is pivotally supported on the lower rear part of the vehicle body so as to be vertically swingable (support shaft 5), and the rear part is connected to the vehicle body by the rear cushion unit 6 for buffer suspension. It was done.

A cover 7 is attached to the swing case 3, and a power transmission system is housed inside. In the power transmission system, first, a drive V pulley 9 is axially mounted on a crankshaft 8 protruding into the swing case 3, and a V belt 12 is hung between the driven V pulley 11 and an intermediate shaft 10. The transmission is arranged as the primary transmission. The rotation of the driven V pulley 11 is transmitted to the intermediate shaft 10 via a centrifugal shoe type starting clutch 13.
Next, the drive gear 14 formed on the intermediate shaft 10 and the driven gear 16 fixed to the rear axle 15 are engaged with each other, and the gear transmission is provided as a secondary transmission. The gear transmission is housed in an oil bath type in a separate chamber 18 defined by an inner cover 17.

The rear axle 15 projects outward from the swing case 3 on the same side as the crank case 2, and its tip end is axially supported by the rear end of a swing arm 19 extending from the opposite side of the crank case 2.

A brake drum 22 having an open swing case side is formed at an inner center portion of a wheel disc 21 that supports the rim 20 of the rear wheel 4, and a rear axle 15 is formed by a shaft hole boss 24 extending from a side plate 23 on the opposite side to an inner surface side. Is rotatably supported by. On the rear axle 15 adjacent to the outer surface side of the side plate 23, a drive disk 26 integrally supported by a spline 25 is arranged.

As shown in FIG. 2, a large number of recessed chambers 27 are formed on the surface of the drive disc 26 facing the brake drum side plate 23.
A rubber damper 28 having a similar outer shape and having an inner hole 30 is fitted therein. On the other hand, many protrusions are formed on the outer surface of the brake drum side plate 23.
29 is formed and fits into the inner hole 30 of the rubber damper 28. That is, the brake drum 22 and the drive disc
The rubber damper 28 couples 26 in the rotational direction, and the driving force of the rear axle 15 is transmitted to the brake drum 22 and the rear wheel 4 via the drive disk 26. The rubber damper 28 buffers torque transmission during this period.

Reference numeral 31 is a brake panel extending from the swing case 3 so as to face the open surface of the brake drum 22, and a brake cam 32 is pivotally supported on the lower portion. The cam shaft 33 projects to the outside and the brake lever 34 is fixed. The brake lever 34 faces downward, and the rear brake cable 35 is routed along the lower surface of the vehicle body.

In this way, the rear wheels 4 are driven by the engine 1 without any trouble,
Since the rubber damper 28 cushions not only the shock at the time of sudden acceleration / deceleration but also the shock when the rear wheel 4 jumps and comes into contact with the ground, damage to the rear axle 15 and the reduction gears 14, 16 is effectively prevented.

FIG. 4 shows another embodiment of the brake drum 22a.
The drive disk 26a is rotatably supported on the rear axle 15a with the open surface facing away from the other side, and the drive disk 26a connected to the rear side by a spline 25a is connected in the rotational direction via a rubber damper 28a. It is the same as the one in the figure.
The brake panel 36 is arranged on the swing arm 19 side.
Then, the brake cam 32a is arranged on the upper part, and as shown by the dotted line in FIG. 3, the upward brake lever 34a is fixed and the rear brake cable 35a is arranged above the swing case 3, and as described above, It eliminates the anxiety that when it is laid down below, it collides with other objects and is easily damaged. In this way, since the swing case 3 can be used without changing the brake panel 31, the components can be used in common to improve the routing without significantly increasing the cost.

[Effect of device]

As described above, the rear wheel axle support device in the unit swing type engine of the motorcycle according to the present invention rotates the brake drum integrated with the rear wheel on the rear axle that projects outward on the same side as the crankcase of the swing case. A drive disk, which is freely supported and is opposed to the outer surface of the side plate of the brake drum, is fixed to the rear axle so as to rotate integrally therewith, and a rubber damper is interposed between the side plate of the brake drum and the drive disk to buffer the transmission of rotational torque. Since the rear axle is rotatably supported by the free end of the swing arm extending rearward from the other side of the crankcase, the rear axle is stabilized from both sides by the swing case and the swing arm. While it can be freely rocked, it is added to the rear axle due to abrupt rotation changes of the rear wheels. Shock torque rubber damper is buffered can prevent damage to the rear axle and the reduction gear,
Further, since a large shock load is not transmitted to the rear axle and the reduction gear, the strength of the rear axle and the reduction gear can be reduced, and the cost can be reduced. Further, even during sudden acceleration / deceleration during traveling, acceleration / deceleration can be smoothly performed by the damper action of the rubber damper that buffers the transmission of the rotational torque, and the riding comfort can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of a unit swing type engine taken along the arrow BB of FIG. 3 showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a rubber damper portion taken along the arrow AA of FIG.
FIG. 3 is a side view of the scooter, and FIG. 4 is a plan view partially crossing a main part of a unit swing type engine showing another embodiment. 1 ... Engine, 2 ... Crankcase, 3 ... Swing case, 4 ... Rear wheel, 15,15a ... Rear axle, 22,22a ... Brake drum, 26,26a ... Drive disk, 28,28a ... Rubber damper.

Claims (1)

[Scope of utility model registration request] 1. A swing case extending rearward is integrally connected to one side of a crankcase, and a rear wheel is pivotally supported at a rear portion of the crankcase so that the swing case can be vertically swung so as to be buffer-suspended at a lower rear portion of a vehicle body. In the rear wheel pivotal support device for the unit swing type engine of the above motorcycle, the brake drum integral with the rear wheel is rotatably supported on the rear axle protruding outward on the same side as the crankcase of the swing case, A drive disc facing the outer surface of the side plate of the brake drum is fixed to the rear axle so as to rotate integrally therewith, and a rubber damper for buffering the transmission of the rotation torque is interposed between the brake drum side plate and the drive disc to couple them in the rotating direction. , A protruding end of the rear axle is rotatably supported by a free end of a swing arm extending rearward from the other side of the crankcase. Rear wheel shaft supporting apparatus in the unit swing type engine of the motorcycle, characterized in that the.