JPH0649474B2 - Rear wheel suspension system for motorcycles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rear wheel suspension device that supports a rear wheel of a motorcycle by a cantilever type rear arm.

[Conventional technology]

Conventionally, a cantilever type rear arm as a rear wheel suspension device is provided with a single rear arm that is swingably supported at the rear portion of a vehicle body frame, and a cantilever type rear wheel is supported at its rear end. In small motorcycles such as scooters, it has long been known as a so-called unit swing type drive device in which an engine and a rear arm are integrally swingable. Further, in recent years, in order to reduce the weight of the rear wheel suspension device, a cantilever type rear arm has attracted attention again for a large motorcycle (for example, Japanese Utility Model Publication No. 53-53237).

[Problems to be solved by the invention]

Generally, when a rear wheel is supported by a cantilevered rear arm, the grounding point of the rear wheel and the axis of the rear arm are offset in the vehicle width direction. It receives a large bending force as well as a bending force in the direction. Since the base end of the rear arm is rotatable with respect to the body frame, the influence of the bending force is not a big problem in design, but it is often designed in order to increase the torsional rigidity in the rear arm which should be lightweight. With difficulty.

[Objects of the Invention, Means for Solving Problems]

The present invention aims to alleviate the above design difficulties,
It is designed to shorten the length of overhang of the rear wheel from the rear arm as much as possible, and to reduce the torsional torque acting on it as much as possible. A rear wheel suspension system for a motorcycle having a single swinging portion supported by a rear end and supporting a rear wheel inside a rear end of the swinging portion. Provided at the rear end of the moving part is a protruding part projecting to the rear wheel side from the swinging part and having a rear wheel axle bearing mounted therein, and the rear wheel axle rotatably supported by this protruding part. ,
A flange member having a structure in which the outer peripheral portion is formed with a certain width, is positioned between the protruding portion and the rear wheel, and the fitting type connection boss portion of the shaft center faces the protruding portion, is fixedly fitted;
A rear wheel is mounted on the outer peripheral portion of the flange member on the side opposite to the rear arm, and a braking disc is mounted on the rear arm side so as to be positioned inside the rim of the rear wheel and around the projecting portion, and the braking caliper is mounted on the braking portion. It is characterized in that a part of the rear arm is faced between the disc and the rear wheel and is arranged around the rear arm at a position overlapping the rear arm in a plan view, and a portion of the rear arm facing the braking disc is formed flat. is there.

〔Example〕

Hereinafter, the present invention will be described with reference to the illustrated embodiment. In the drawings, 1 is a motorcycle and 2 is a body frame thereof. A front wheel 4 is rotatably supported by a front fork 3 on a front portion of the vehicle body frame 2, and a rear wheel 6 is supported on a rear portion thereof by a rear arm 5. Reference numeral 7 denotes a shock absorber that connects the free end of the rear arm 5 and the vehicle body frame 2 and supports the vertical movement of the free end of the rear arm 5 so as not to be directly transmitted to the vehicle body frame 2. Reference numeral 8 denotes a power unit for driving the rear wheels 6 via a chain 9 and a driven sprocket 10, and a fuel tank 11 and a passenger's seat 12 are provided above the power unit.

As shown in FIG. 2, the rear arm 5 is formed by casting an aluminum alloy, and is machined to complete the rear arm 5. The rear arm 5 is a substantially cylindrical boss portion pivotally supported on the rear portion of the body frame 2.
5a and one side thereof, that is, a substantially square tubular rear wheel support that curves rearward from a position deviated from the center in the width direction of the vehicle to a position "one side" so as to avoid the tires of the rear wheels and extends rearward. Arm
With 5b. The rear wheel support arm portion 5b constitutes the swing portion according to the present invention. In the figure, a quadrilateral bulge indicated by a chain double-dashed line indicates the sectional shape of the support arm 5b. The rear arm 5 has a base end of the support arm portion 5b extending obliquely rearward from the outside of the tire in a plan view, and is bent from the side of the tire toward the inside of the rim to have a substantially V shape. Has been formed. The rear end of the rear wheel support arm portion 5b is closed, and a side surface thereof has a protrusion 5c that protrudes toward the center of the body frame 2 in the width direction, in other words, toward the rear wheel 6. The left and right through holes 5d formed in the vicinity of the rear end of the rear arm 5 including the protrusion 5c have two
The individual ball bearings 5e, 5e are fitted to each other, and a flange member 15 having a mounting flange and a flange member 16 of the driven sprocket 10 are coaxially fitted to the ball bearings 5e and 5e, respectively. The flange members 15 and 16 are ball bearings 5e.
Are fitted to each other by an inner spline formed inside the fitting type coupling boss portions 15a, 16a and an outer spline formed on the outer surface of the support shaft 17 as an axle according to the present invention, and are non-rotatably coupled to each other. It is fastened by a nut 18 so as not to come off. 17a is each flange member 1
It is a cylindrical portion that supports the inner ends of 5 and 16. In this embodiment, the outer spline formed on the outer surface of the support shaft 17 has a large diameter portion on the head 17b side and a small diameter on the nut 18 side, so that the support shaft 17 can be easily inserted and removed. is there. That is, the flange members 15 and 16 and the support shaft 17 are rotatably supported by the protrusion 5c via the ball bearing 5e. And the flange member 1
Mounting flanges 15b and 16b are respectively provided on 5 and 16 so as to close the through hole 5d of the rear arm 5. The mounting flange 15b of the flange member 15 is arranged on the rear wheel 6 side of the rear arm 5, and the mounting flange 16b of the flange member 16 is arranged on the side of the rear arm 5 opposite to the rear wheel 6.

The mounting flange 15b of the flange member 15 has an outer peripheral portion 1
5c is formed with a certain width (thickness), and this outer peripheral portion 1
The rear wheel 6 and the braking disc 20 are supported on one side and the other side of 5c. The rear wheel 6 is attached to the outer peripheral portion 15c on the side opposite to the rear arm 5. Braking disc 20
Is between the rear wheel 6 and the rear wheel support arm portion 5b, that is, the rear wheel 6
Is arranged on the inner side of the rim 6b and on the outer side in the radial direction of the protrusion 5c, and cooperates with the caliper 21 and the pad 22 to form a disc brake. The rear arm 5
A flat surface 5f is formed on a portion of the rear wheel support arm 5b facing the braking disc 20. Reference numeral 23 is a bolt for fixing the braking disc 20 to the flange member 15 together with the rear wheel 6 described later. As shown by the chain double-dashed line in FIG. 2, a part of the caliper 21 faces the braking disc 20 and the rear wheel 6 and overlaps the rear arm 5 around the rear arm 5 in plan view. It is located in a position. The rear wheel 6 is a so-called cast wheel in which the spoke 6a, the rim 6b, and the hub 6c are integrally cast with a light alloy, and the spoke 6a is opposite to the rear wheel support arm portion 5b from the widthwise center of the rim 6b. It is provided so as to be deviated in the direction, and forms a space inside the rim 6b where the disc brakes such as the braking disc 20 and the caliper 21 are arranged. 6d is a tire.

The mounting flange 16b of the flange member 16 is provided with a mounting bolt 26 protruding inward via a cushioning rubber 25, and the driven sprocket 10 is fastened thereto. Reference numeral 27 is a bolt for fixing the lower end of the shock absorber 7 to the rear arm 5, and 28 is a decorative cover fitted to the inner peripheral surface of the hub 6c.

The rear end of the rear arm 5 adjusts the tension of the chain 9, so that the rear arm 5 is supported so as to be adjustable in the front-rear direction with respect to the vehicle body frame 2 and lockable at that position. That is, the support ring 2a of the rear arm 5 is welded to the body frame 2,
A support member 31 for supporting the pivot 30 is slidably supported in the front-rear direction, and a bolt 32 and two nuts 33 provided on the support member 31 can adjust the front-rear position and lock it. It is configured to be possible. A spacer 34 is interposed between the left and right support members 31, and the spacer 34 rotatably supports both ends of the boss portion 5a via bearings 35, 35. 36 is a dust seal.

Since this embodiment has the above construction, the power unit 8
Is driven, and the driven sprocket 10 is driven through the chain 9.
Is driven, the flange member 16 rotates, and accordingly, the flange member 15 also rotates via the support shaft 17, and the rear wheels 6 are driven to travel the motorcycle 1. When the rear wheel 6, the chain 9 and the driven sprocket 10 are exchanged during assembly or inspection and maintenance, the rear arm 5 is a cantilever type and there is no rear arm 5 on one side of the wheel. The wheels can be exchanged. Also, when replacing the driven sprocket 10, the nut 1
By removing 8 and removing the support shaft 17, it is possible to immediately remove the driven sprocket 10 together with the flange member 16,
Further, since the flange member 15 remains supported by the rear arm 5 by the bearing 5e even after the removal, the reassembly is easy. Further, even when the player participates in the competition, a plurality of driven sprockets 10 having different numbers of teeth are attached to the flange member 16 in advance to prepare for the replacement work, which enables quick replacement work.

As described above, according to the present invention, in a motorcycle having a cantilevered rear arm, a bearing is provided on a protruding portion that protrudes to one side from the rear end of the rear arm, and the rear wheel is supported by the bearing. Since it is supported, the length of the rear wheel offset from the axis of the rear arm in the vehicle width direction can be shortened, so that the twisting force acting on the rear arm can be reduced. Further, since the braking disk is arranged radially outward of the protruding portion, the number of protruding objects protruding toward the vehicle side is reduced compared to the case where both the braking disk and the driven sprocket are arranged outside the rear arm. There is an effect that the width does not become wide.

Further, since the flange to which the rear wheel and the braking disc are attached is fixedly fitted to the axle with the fitting type connection boss portion facing the inside of the protrusion, the inside of the protrusion should be part of the flange attachment portion. Therefore, the rear wheel / braking disc mounting portion can be formed narrow while ensuring the length of the fitting portion between the flange and the axle. At the same time, the outer peripheral portion of the flange is formed to have a certain width, and the rear wheel is mounted on the outer peripheral portion on the side opposite to the rear arm and the braking disc is mounted on the rear arm side. It can be fixed to and can be firmly supported.

That is, the rear wheel and the braking disc support structure can be formed narrow while ensuring rigidity. Moreover, since the braking disc is arranged around the protrusion, the periphery of the protrusion provided to reduce the offset amount of the rear wheel as described above can be utilized without waste, and the mounting density of parts is increased and the rear arm rear portion can be used. The width becomes narrower.

Further, since the braking caliper is partially exposed between the braking disc and the rear wheel and is disposed around the rear arm and at a position overlapping the rear arm in plan view, the braking caliper can be brought as close as possible to the rear arm. . The space where a part of the braking caliper faces is skillfully utilized as a space formed by sandwiching the outer peripheral portion of the flange by both of them in order to enhance the supporting strength of the rear wheel and the braking disc. .

In addition, since the portion of the rear arm that faces the braking disc is formed flat, the rear arm is less likely to interfere with the braking disc, and both can be brought as close as possible.

Therefore, the rear arm rear portion can be formed narrow, and the braking caliper and the braking disc can be arranged as close to the rear arm as possible, so that a compact rear wheel suspension device can be obtained. When the rear wheel suspension system becomes narrow and compact in this way, the unsprung load decreases and
The torsional rigidity of the rear arm can be sufficiently ensured.

As in the embodiment, if the rear wheel spokes are provided so as to be offset from the center of the rim in the width direction in the direction opposite to the rear wheel support arm, even if the rear arm axis is brought close to the rear wheel, The space existing on the inner circumference of the rim can be increased, and the disc brake can be easily accommodated without difficulty. Furthermore, if the rear arm is made entirely of light alloy and is hollow, the weight of the vehicle can be significantly reduced compared to the conventional steel arm. In the plan view, the rear wheel support arm can be made to approach the wheel as a whole by bending only the tire portion outward in an arc shape.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show one embodiment of the present invention. FIG. 1 is a side view of a motorcycle, and FIG. 2 is an enlarged sectional view showing a II-II section thereof. 5: rear arm, 5a: boss, 5b: rear wheel support arm, 5c: protruding part, 20: braking disc, 21: caliper.

Claims (3)

[Claims] 1. A cantilever type rear arm having one swinging portion that is swingably supported on the rear portion of a body frame and extends rearward, and supports a rear wheel inside a rear end portion of the swinging portion. In the rear wheel suspension device of a motorcycle, comprising:
A rear wheel axle bearing is mounted on the inner side of the swinging portion so that the rear wheel axle is rotatably supported by the protruding portion. A flange member having a structure that is formed between the protruding portion and the rear wheel and has a fitting centered connecting boss portion facing the inside of the protruding portion is fitted and fixed to the rear arm on the outer peripheral portion of the flange member. The rear wheel is mounted on the opposite side, and the braking disc is mounted on the rear arm side so as to be positioned inside the rear wheel rim and around the protrusion, and the braking caliper is mounted between the braking disc and the rear wheel. A rear wheel suspension of a motorcycle, characterized in that the rear arm is arranged so as to partially face the rear arm and at a position overlapping the rear arm in a plan view, and a portion of the rear arm facing the braking disk is formed flat. Apparatus. 2. The rear wheel has cast spokes, which are offset from the center of the rim in the width direction in the direction opposite to the swinging portion, and the braking disc is arranged inside the rim. The rear-wheel suspension system for a motorcycle according to claim 1. 3. The rear wheel suspension system for a motorcycle according to claim 1, wherein the rear arm is made of light alloy and is cast into a hollow shape.