JP2710982B2 - Rear wheel suspension for motorcycles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rear wheel suspension system for a motorcycle.
A power transmission case containing a power transmission mechanism for an engine and a rear wheel, and a rear wheel suspension device that supports the rear wheel to a vehicle body via a power unit in which an axle of the rear wheel is integrated. It is.

[Related Art] Conventionally, as a rear wheel suspension device applied to a motorcycle,
There is known a structure in which an engine, a power transmission case, and a rear wheel axle are integrated via a power unit to support the rear wheel to a vehicle body. A technique disclosed in JP-A-59-109593 is mentioned.

This technology is the first between the power transmission case and the body frame.
And a second cushion unit is disposed between the rear wheel axle and the vehicle body frame. Both of the cushion units are substantially viewed from the side of the vehicle body. Both cushion units have a positional relationship such that they overlap with each other, and the axis of the cushion unit is disposed obliquely forward and upward so as to pass behind the axle of the rear wheel.

[Problems to be Solved by the Invention] However, in the above-described conventional technology, when power is applied to the rear wheel 7 at the time of starting or accelerating, a phenomenon such as lifting of the power unit occurs.

Therefore, due to the upward movement of the power unit,
When an elastic vibration isolating member is interposed in the mounting portion of the power unit to the vehicle body, the vibration isolating effect may be impaired, and the ride comfort may be reduced.

The present invention is to solve such a problem remaining in the prior art.

[Means for Solving the Problems] The present invention provides a rear wheel suspension device for a motorcycle that can effectively solve the above-mentioned problems. In particular, the present invention provides an engine for a motorcycle and the rotation of the engine for the rear wheel. A power transmission mechanism for transmitting power to the power unit is housed, and a power transmission unit integrally formed with a power transmission case in which the rear wheel is rotatably supported is swingably connected to a lower portion of the vehicle body at a front portion thereof. And, in a rear wheel suspension device in which the vehicle body is connected via a cushion unit at a rear portion, the cushion unit is disposed on both sides of a power unit, and one of the cushion units has an axis line of the axle of the rear wheel. And the other cushion unit is positioned at a position where the axis intersects the axle or at a position forward of the same. As a first feature, the power unit has a front end fixed to the vicinity of the engine, and a rear end connected to the rear wheel axle. A swing arm is mounted, and the other cushion unit is connected to the swing arm in a cantilever structure. A third feature is that the swing arm is formed by casting.

[Operation] The rear wheel suspension device for a motorcycle according to the present invention has the above-described configuration, so that both cushion units are installed at the rear of the vehicle body as much as possible to enlarge the space above the power unit, and further to the rear wheel. Even if a force in the direction of lifting the power unit acts upon the power transmission, the force for lifting the front of the power unit upward is reduced by the resilience of the other cushion unit.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

In FIG. 1, reference numeral 10 denotes a scooter type motorcycle to which the present embodiment is applied, and a vehicle body frame 11, a front fork 12 rotatably mounted on a front portion of the vehicle body frame 11, A front wheel 13 rotatably mounted on the lower end of the front fork 12, a steering handle 14 mounted on the upper end of the front fork 12, and the body frame
11, a power unit 16 mounted on the lower rear part so as to swing vertically, a rear wheel 17 rotatably mounted on the power unit 16, the front fork 12 and the vehicle body. A front cover 18 provided to cover a front portion of the frame 11, a floor panel 19 that covers a substantially central portion of the body frame 11, and forms a footrest for a rider at a lower rear portion of the front fork 12, A rear cover 20 provided to cover a rear portion of the frame 11 and an upper portion of the power unit 16;
And a pair of cushion units 21 and 22 interposed between the power unit 16 and the power unit 16. The power unit 16 and the cushion units 21 and 22 constitute the rear wheel suspension device 23 of the present embodiment.

 Next, these details will be described.

The power unit 16 has a front portion that is
A pair of support members 24 protruding downward from each of both sides of the vehicle body at a position closer to the rear than the substantially central portion at the lower part of 11, and a pivot shaft 25 mounted between the support members 24, Further, it is connected to the vehicle body frame 11 via a substantially L-shaped link 26 rotatably connected to the pivot shaft 25.

The link 26 is provided with a pair of stoppers 27 extending upward. Each of the stoppers 27 is a cross member 28 attached to the vehicle body frame 11 at a position further above the pivot shaft 25. In, rubber 29
And from the front and rear direction of the vehicle body.

Next, the rear wheel suspension device 23 of the present embodiment will be described.

Power unit constituting rear wheel suspension device 23 of the present embodiment
On the side 16 (on the right side of the vehicle body) on the side where the rear wheel 17 is mounted, a swingome 30 made of cast iron is provided.

This swing dome 30 is disposed so as to be substantially parallel to a power transmission case 32 continuously provided rearward from the engine 31 at a front portion of the power unit 16 with a space in the width direction of the vehicle body, The front end of the engine 31
Are fixed to the side rear end of the crankcase 33 by bolts 34 at two places, and the rear end is
The axle 35 has a bearing 36 as shown in FIGS.
And is fixed by a nut 37.

A mounting portion 30a extending substantially below the axle 35 is formed integrally with a rear portion of the swing dome 30, and a pivot shaft is provided on the mounting portion 30a from the power transmission case 32 to the outside of the vehicle body. 38 is fitted, this pivot shaft
The lower end of the one cushion unit 21 is rotatably fitted to 38, and is connected in a state where the lower end is prevented from being detached by a nut 39, and is supported by a cantilever structure.

On the other hand, the upper end of the one cushion unit 21 is rotatably connected to a support member 40 attached to the vehicle body frame 11 via a pivot shaft 41, and the pivot shaft 41 is In a normal state, a line connecting to the pivot shaft 38 provided on the swing dome 30 intersects with the axis of the axle 35 or is located in front of the vehicle body with respect to the axle 35. The installation positions of the two pivot shafts 38 and 41 are set so as to be located at the positions.

Therefore, the axis of one cushion unit 21 erected between these pivot shafts 38 and 41 intersects with the axis of the axle 35, or is located on the front side of the vehicle body with respect to this axle. I have.

Further, as shown in FIGS. 1 to 4, the other cushion unit 22 has a lower end provided on a bracket 42 protruding rearward of the vehicle body at a rear end of the power transmission case 32. A substantially U-shaped connecting member 43 and a bolt 44 rotatably connect with each other.
Is rotatably connected via a pivot shaft 46 to a support member 45 integrally attached to the support member 45.

The pivot shaft 46 is disposed coaxially with the pivot shaft 41 to which the upper end of the one cushion unit 21 is connected.

Further, in the present embodiment, spring guides 49 and 50 for suppressing vibration of the cushion spongs 47 and 48 are attached to the cushion units 21 and 22.

These spring guides 49 and 50 are formed in a substantially cylindrical shape as a whole by a synthetic resin, and as shown in FIGS. 5 and 6, are provided with a fixed length from the upper end at two locations spaced in the circumferential direction. Is formed, and one of the slits S1 extends to the lower end.

Further, flanges 51 and 52 are formed at the lower ends of the spring guides 49 and 50, with which the lower ends of the cushion springs 47 and 48 are brought into contact, and the outer peripheral surfaces are brought into contact with the insides of the cushion springs 47 and 48. A plurality of ridges 53 and 54 are formed along the length direction and at intervals in the circumferential direction.

The spring guides 49 and 50 are formed such that the outer diameter D at the lower end thereof is equal to or larger than the inner diameter d of the cushion springs 47 and 48, and
Due to the presence of S1, it is mounted in the cushion springs 47 and 48, and is brought into close contact with the inner surfaces of the cushion springs 47 and 48 by its elasticity, so that the vibration generated in the cushion springs 47 and 48 is absorbed by its elasticity. Has become.

In addition, the spring guides 49 and 50 have
Since 53 and 54 are formed, the cushion spring 47
・ Because the contact part with 48 is small, and it is formed so that it gradually becomes smaller as it goes to the upper end,
The mountability of the cushion springs 47 and 48 is good, and the operation of the cushion springs 47 and 48 is smoothly permitted.

In addition, the ridges 53 and 54 provide good contact with the cushion springs 47 and 48, so that the vibration damping action is effectively performed.

On the other hand, in FIGS. 2 to 4, reference numeral 55 denotes a silencer, the front end of which is fastened to the crankcase 33 by bolts 34 for fixing the swing arm 30 to the crankcase 33. The bracket 56 provided at the rear end is fixed to the support portions 30b and 30c formed integrally with the swing arm 30 by bolts 57,
It is attached to the power unit 16.

Thus, in the rear wheel suspension device 23 of this embodiment configured as described above, power is transmitted to the rear wheel 17 and is transmitted to the power unit 16 as shown by an arrow (e) in FIG. When a force acts to lift the front part of the cushion unit 22, the resilient force (f) of the other cushion unit 22 acts to amplify the force (e) as shown in FIG. Since the cushion unit 21 is positioned forward and backward with respect to the other cushion unit 22 across the axle 35, the resilience (g) of the one cushion unit 21 is, as shown in FIG. It acts to cancel the force (e) for lifting the power unit 16 and the elastic force (f).

Therefore, the force for pushing up the power unit 16 is suppressed.

By the way, in the above-described embodiment, a state is shown in which one cushion unit 21 is mounted under the condition that the axis thereof substantially intersects the axis of the axle 35.

By setting such an installation state in a normal state such as a non-riding state, the above-described operation can be effectively obtained.

That is, when one of the cushion units 21 is installed under the above-described conditions in the non-riding state, the cushion unit 21 is contracted during riding, and the axis thereof is shifted to the axle 35.
This is because they move forward.

Further, in a state where the vehicle body is lifted by the stand device and the load applied to the cushion unit 21 is removed,
When one of the cushion units 21 is installed under the above conditions, the amount of shrinkage of the cushion unit 21 during riding is larger than in the above-described case, and the effect of preventing the vehicle body from lifting is more effective.

Furthermore, in the present embodiment, since the connection between the swing arm 30 and one of the cushion units 21 is a cantilever structure using the pivot shaft 38, the space occupied around the mounting portion 30a is reduced, and the swing arm 30 itself is Since the shape of the swing arm 30 is simplified, casting of the swing arm 30 becomes easy.

The various shapes, dimensions, and the like of the components shown in the embodiment are merely examples, and can be variously changed based on the type of motorcycle to be applied, design requirements, and the like.

For example, when there is room in the space between the power unit 16 and the seat 15, as shown in FIG. 7, the mounting portion 30a provided on the swing arm 30 is positioned further forward of the vehicle body than in the previous embodiment. As a result, the moment applied to the power unit 16 by one of the cushion units 21 is increased, and the power unit 16
Can be more effectively suppressed.

In the above embodiment, each cushion unit
Although the example in which the rear portion of the body frame 11 to which the upper end portions of 21 and 22 are attached is arranged obliquely upward has been described,
Instead, as shown in FIG. 8, it may be bent obliquely downward.

With such a configuration, the space formed in the rear cover 20 can be enlarged, and the storage volume can be increased when an article storage box is provided below the seat 15 in the rear cover 20. .

[Effects of the Invention] As described above, according to the rear wheel suspension device for a motorcycle according to the present invention, one of the cushion units provided on both sides of the power unit intersects with the axis of the rear wheel axle. Position so as to be positioned at or forward of the rear wheel, even if a force that lifts the front portion of the power unit acts on the rear wheel when power is applied to the rear wheel, the power is applied to the one side. It is possible to suppress the lifting of the power unit by canceling out due to the resilience of the cushion unit, and to ensure good ride comfort.

Also, since the lower end of the other cushion unit is supported by the swing arm by a cantilever structure,
The structure of the support portion of the swing arm is simplified.

Further, by forming the swing arm by forging, it is possible to simplify the manufacturing of the component for mounting the other cushion unit, in combination with the simplification of the structure.

[Brief description of the drawings]

1 to 6 show one embodiment of the present invention. FIG. 1 is a left side view of a motorcycle to which one embodiment is applied, and FIG. 2 is a right side in which main parts are enlarged. 3, FIG. 3 is a sectional view taken along the line III-III in FIG. 2, FIG. 4 is a plan view showing an enlarged main part, and FIG. 5 is a view taken along the line VV in FIG. FIG. 6 is a cross-sectional view, FIG. 6 is an external perspective view showing the relationship between a spring guide and a cushion spring, and FIGS. 7 and 8 each show another embodiment of the present invention. FIG. 7 is a lower end of the cushion unit. FIG. 8 is an enlarged right side view showing an example in which the attachment positions of the parts are changed, and FIG. 8 is a left side view showing the example in which the shape of the body frame is changed. 10 ... motorcycle, 11 ... body frame, 16 ... power unit, 17 ... rear wheel, 21 ... one cushion unit, 22 ... the other cushion unit, 23 ... rear wheel suspension device, 30 ... Swing arm, 31 ... Engine, 32 ...
Power transmission case, 35 ... axle.

Claims (3)

(57) [Claims] An engine of a motorcycle and a power transmission mechanism for transmitting the rotation of the engine to a rear wheel are housed, and a power transmission case in which the rear wheel is rotatably supported is integrally formed. A rear wheel suspension device comprising a power unit connected to the lower part of the vehicle body at a front part thereof and a vehicle unit connected to the vehicle body via a cushion unit at a rear part thereof. And one cushion unit is disposed so that its axis is located behind the axis of the axle of the rear wheel, and the other cushion unit is disposed at a position where its axis intersects the axle or more. Rear wheel suspension device for a motorcycle, characterized in that the rear wheel suspension device is also arranged so as to be located forward. 2. A swing arm having a front end portion fixed to the vicinity of the engine and a rear end portion connected to an axle of a rear wheel is mounted on the power unit, and a cushion unit is connected to the swing arm in a cantilever structure. Rear wheel suspension system for motorcycles, characterized in that 3. The rear wheel suspension for a motorcycle according to claim 2, wherein the swing arm is formed by casting.