JPH11255173A - Rear wheel suspension for motorcycles - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a rear wheel suspension device for a motorcycle in which a difference in weight between right and left can be reduced, a rear frame is short and high strength and rigidity can be secured. SOLUTION: An internal combustion engine main body 25 is integrally provided at a front portion of a transmission case 23 containing a transmission mechanism, and a power unit 20 which supports a rear wheel at a rear portion is swingably supported with respect to a vehicle body frame 5. A rear wheel suspension device for a motorcycle in which a shock absorber 50 interposed between the body frame 5 and the power unit 20 is provided on the opposite side of the transmission case 23 and the rear wheel 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit swing type motorcycle provided with a power unit for integrally supporting an internal combustion engine body at a front portion of a transmission case having a transmission mechanism therein and supporting a rear wheel at a rear portion. The present invention relates to a wheel suspension device.

[0002]

2. Description of the Related Art A general example of a rear wheel suspension system of a unit swing type motorcycle (Japanese Patent Laid-Open No. 4-292285) is shown in FIG.

[0003] A rear frame 02 contiguous to the front frame 01 extends obliquely upward rearward from the floor portion 01a.
Luggage box between right and left rear frames 02, 02
010 is sandwiched and supported, and a carrier 011 is mounted behind the 010.

[0004] The power unit 05 has an internal combustion engine main body 06 integrally provided at the front of a transmission case 07 containing a transmission mechanism, and an upper portion of the internal combustion engine main body 06 is connected to a rising inclined portion of a rear frame 02 via a hanger link 08. Be luggage box
010 is swingably supported below.

[0005] The transmission case 07 is biased to the left of the vehicle body, and a rear wheel 09 is supported at the rear portion thereof at the center of the vehicle width direction. A shock absorber 03 is interposed between the rear portion of the transmission case 07 deflected to the left and the rear frame 02 substantially above the rear portion.

Therefore, the shock absorber 03 is provided on the same side as the transmission case 07 with respect to the rear wheel 09, and the mounting position with the rear frame is located behind the hanger link 08 to which the power unit 05 is mounted.

[0007]

Since the shock absorber 03 is disposed on the same side as the transmission case 07 which is deviated to the left of the vehicle body, the weight is deviated to the left, and the difference between the left and right weights is large. The rear frame 02 has a long cantilever structure from the front rising part where the power unit 05 is mounted to the upper rear part where the shock absorber 03 is mounted, so high strength and rigidity are required, and weight is increased by reinforcement. .

Therefore, an example in which a rear wheel suspension mechanism including a shock absorber arranged at the center in the vehicle width direction is provided under the floor (below the floor portion 01a) (Japanese Patent Publication No. 1-52237, Japanese Patent Publication No. 3-10556).
However, it cannot be applied to motorcycles with a fuel tank under the floor.

The present invention has been made in view of the above point, and the object thereof is to reduce the difference in weight between left and right,
It is an object of the present invention to provide a motorcycle rear wheel suspension device capable of securing a high strength and rigidity with a short rear frame.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an internal combustion engine body integrally provided at a front portion of a transmission case having a built-in transmission mechanism, and a rear wheel supported at a rear portion. In a motorcycle rear wheel suspension device in which a power unit is supported to be swingable with respect to a body frame, a shock absorber interposed between the body frame and the power unit sandwiches the transmission case and a rear wheel. And a rear wheel suspension device for a motorcycle provided on the opposite side.

Since the shock absorber is provided on the opposite side of the transmission case and the rear wheel, it is possible to minimize the deviation of the weight to one side in the vehicle width direction and to reduce the difference between the left and right weights.

According to a second aspect of the present invention, a power unit integrally including an internal combustion engine main body at a front portion of a transmission case having a transmission mechanism therein and supporting a rear wheel at a rear portion swings with respect to a vehicle body frame via a pivot. In a rear wheel suspension device for a movably supported motorcycle, a first link member swingably supported on the opposite side of the power unit with the transmission case and a rear wheel interposed therebetween, and the power unit of a vehicle body frame. A shock absorber having one end pivotally connected to a pivot pivotally supported and having the other end pivotally connected to one side of the first link member; A rear wheel suspension device including a second link member having the other end pivotally mounted on a side thereof.

A shock absorber and a second link member are pivotally mounted on a first link member pivotally supported on the opposite side of the power unit with the transmission case and the rear wheel therebetween, and the transmission case and the rear wheel are sandwiched therebetween. Since the link mechanism of the rear wheel suspension is formed on the opposite side, it is possible to minimize the deviation of the weight toward the transmission case side in the vehicle body width direction, and to reduce the difference between the left and right weights.

[0014] Since the pivotal attachment portion where the shock absorber is attached to the vehicle body frame is located near the pivot where the strength and rigidity of the power unit to be pivotally supported are both high, the required strength and rigidity can be easily secured without reinforcing the vehicle body frame. And an increase in weight can be avoided.

The pivot portion of the shock absorber is located near the pivot.
Since the suspension device is constituted by the link mechanism, shortage of the stroke of the shock absorber can be eliminated. In addition, by using a link mechanism to make the pivot of the shock absorber close to the pivot, it is not necessary to increase the height of the rear frame of the body frame, and the body frame is shortened to reduce the weight of the body and free design. The degree can be increased.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a left side view of a scooter type motorcycle 1 provided with a unit swing internal combustion engine according to the present invention.

A vehicle body front and a vehicle body rear are connected via a low floor portion, and a vehicle body frame forming a frame of the vehicle body includes a front frame 3 extending downward from a head pipe 2 at a vehicle body front portion, A pair of left and right horizontal frames 4, 4, which are branched into two at the lower portion of the front frame 3 and extend rearward below the floor portion, and inclined portions 5 a that rise obliquely rearward from the rear portions of the horizontal frames 4, 4. A pair of left and right rear frames 5 and 5 including horizontal portions 5b and 5b extending rearward at an appropriate height after forming 5a.

The horizontal portion 5 of the pair of right and left rear frames 5, 5
A luggage box 6 integrated with a tail portion is mounted on b and 5b, and a seat (not shown) is provided on the luggage box 6 so that the opening thereof can be freely opened and closed. The carrier 7 is attached to the rear of the luggage box 6.

A steering shaft 11 having a handlebar 10 is provided at an upper part of the vehicle body, a lower side of the steering shaft 11 is connected to a front fork 12, and a front wheel 13 is pivotally supported at a lower end of the front fork 12. Steered by the handle 10.

As shown in FIGS. 2 and 3, a frame pivot is provided between the bent portions which transition from the inclined portions 5a, 5a of the left and right rear frames 5, 5 to the horizontal portions 5b, 5b.
On the other hand, an engine pivot 17 is installed via rubber bushes 24a, 24a between a pair of left and right hanger brackets 24, 24 projecting from the front upper surface of a unit swing case 21 of the power unit 20, and a frame pivot 15
The engine hanger link 16 is connected to the engine pivot 17.

That is, as shown in FIG. 3, the engine hanger link 16 has a sleeve 16a pivotally supported by a frame pivot 15 via a rubber bush 15a, and a pair of left and right connecting portions 16b extending rearward from the sleeve 16a. , 16b
Is connected to the engine pivot 17.

A protruding piece 16c protrudes forward from the sleeve 16a, and is fitted in a housing 5d provided on a cross member 5c provided between the upper portions of the inclined portions 5a, 5a of the rear frame 5. The protruding piece 16c is inserted into the elastic body 5e.

Therefore, the rear frame 5 elastically regulates the rotation of the engine hanger link 16 pivotally supported by the frame pivot 15 via the rubber elastic body 5e. With such an engine hanger link 16, the power unit 20
The upper part on the front side is supported by the rear frame 5 and can swing up and down.

At the front of the unit swing case 21 of the power unit 20, a crankcase 22 is formed, and an internal combustion engine 25 is integrally provided. A transmission case 23 extends rearward from the left side of the crankcase 22, Rear wheel at rear
The power of the internal combustion engine 25 is transmitted to the rear wheels 29 by a belt transmission mechanism having an automatic transmission function. Transmission case
The left side surface of 23 is covered with a case cover 23a.

The internal combustion engine 25 is a two-stroke internal combustion engine, in which a cylinder 25a extends forward from the crankcase 22 to the vicinity of the horizontal while leaning forward, and the inclined portions 5a, 5a of the pair of right and left rear frames 5, 5 are provided. The cylinder 25a is located at a position penetrating the space (see FIGS. 1 and 2).

The internal combustion engine 25 employs a crankcase reed valve system in which a reed valve is provided in a crankcase, and an intake pipe 26 extends from an intake port on the upper surface of the crankcase 22 with reference to FIG. 1 and is connected to a carburetor 27. As shown in FIG. 1, an air cleaner 28 mounted on the rear part of the transmission case 23 is connected to the carburetor 27 to introduce air. The fuel tank 35 is mounted and fixed between the horizontal frames 4 and 4 on the floor.

An exhaust pipe 30 extending downward from a lower portion of the cylinder 25a of the internal combustion engine 25 is provided on the right side of the vehicle body by bypassing the lower part of the crankcase 22 backward and rightward.
(See FIG. 1).

On the right side of the crankcase 22, a fan cover 22a for covering the ACG and the cooling fan is provided.
Mounting bosses 22b, 22b are formed at two positions above and below the peripheral edge portion behind the fan cover 22a of the crankcase 22, and the mounting portions of the muffler support bracket 32 and the link support bracket 33 overlap the mounting bosses 22b, 22b. Bolt 34
It is fastened together by 34 (see FIGS. 2 to 4).

The muffler 31 is fixed to a portion extending rearward of the muffler support bracket 32, and the muffler 31 is supported by the crankcase 22 via the muffler support bracket 32. The link support bracket 33 is a plate member bent in a rectangular shape, and its upper and lower ends are fastened to the crankcase 22 together with the muffler support bracket 32 by bolts 34,34.

At the bent portion of the link support bracket 33,
Cushion arm as a first link member having a triangular shape
The lower corner 40 a of the 40 is pivotally supported by a pivot 41, and the cushion arm 40 is swingably attached to the power unit 20.

The rear end of the cushion connecting rod 43, which is a rod-shaped second link member, is connected to the front corner 40 of the cushion arm 40.
The cushion connecting rod 43 is pivotally connected to a bracket 45 extending rearward at a rising portion of the right rear frame 5 by a pivot 44. ing.

A shock absorber 50 is interposed between the rear corner portion 40c of the triangular cushion arm 40 and the bracket 46 extending above the front portion of the horizontal portion 5b of the right rear frame 5. That is, the front end of the shock absorber 50 is pivotally attached to the bracket 46 by the pivot 47, and the rear end is
It is pivotally attached to the rear corner 40c of the forty.

The pivot 47, which pivotally connects the front end of the shock absorber 50, is located above and close to the frame pivot 15, which pivotally supports the engine hanger link 16, so that the inclined portion 5a of the rear frame 5 has a short horizontal portion. The height of 5b is considerably lower than the conventional one.

The rear end of the shock absorber 50 whose front end is pivotally connected to the lower pivot 47 is connected to the rear corner of the cushion arm 40 located above the muffler 31. It is in a gently inclined posture.

Referring to FIG. 5, the power unit 20 in which the hanger bracket 24 on the upper part of the crankcase 22 is swingably supported by the rear frame 5 via the engine hanger link 16 is shown by a solid line with respect to the body frame. When pivoted upward from above, the pivot 41 of the cushion arm 40 integral with the power unit 20 pivots upward, as shown by the two-dot chain line, and the cushion arm 40 is regulated by the cushion connecting rod 43 and pivots to rotate to the rear angle. The part 40c compresses the shock absorber 50 substantially forward.

Although the front end of the shock absorber 50 is pivotally mounted in the vicinity of the frame pivot 15 which supports the power unit 20 so as to be swingable, a link mechanism is formed in the shock absorber 50 as shown in FIG. In addition, the compression stroke of the shock absorber 50 itself can be sufficiently large, and
Can be used effectively.

Since a shock absorbing link mechanism including a shock absorber 50 is formed on the right side of the vehicle body opposite to the transmission case 23 disposed on the left side of the vehicle body and the rear wheel 29, a weight is provided on one side in the vehicle width direction. Can be minimized and the difference in weight between the left and right sides can be reduced.

The bracket 46 at the pivotal portion where the shock absorber 50 is attached to the vehicle body frame is located near the frame pivot 15, which is high in strength and rigidity, in which the power unit 20 is swingably supported, and thus reinforces the vehicle body frame. The required strength and rigidity can be easily ensured without any increase, and an increase in weight due to reinforcement can be avoided.

Further, since the pivoting portion where the shock absorber 50 is attached to the rear frame 5 is located near the frame pivot 15, the height of the rear frame 5 does not need to be high and is set low. The portion 5b is also not extended rearward, so that the vehicle body frame can be shortened, the weight of the vehicle body can be reduced, and the degree of freedom in design can be increased.

Next, another embodiment will be described with reference to FIG. The vehicle according to the present embodiment is also a scooter-type motorcycle 61, and the body frame also includes a front frame 63, a horizontal frame 64, and a rear frame 65 that are substantially the same as the vehicle.
The power unit 70 has a lower portion of the crankcase 71 connected to and supported by a rising portion of a rear frame via an engine hanger link 75.

That is, a pair of left and right engine hangers 7 for mounting the engine pivot 73 under the crankcase 71.
A frame pivot 67 is provided between a pair of left and right brackets 66, 66 extending rearward from the rising portion of the rear frame 65.
75, a sleeve is supported by a frame pivot 67, a connecting portion 75b extending rearward from the sleeve is connected to the engine pivot 73, and a projecting piece 75c projecting forward from the sleeve is provided at a lower portion of the rear frame 65. Rubber elastic body fitted in a housing 65d provided on the cross member that is erected
65e.

On the right side of the crankcase 71, a muffler support bracket 77 for supporting a muffler 76 is fixed behind the fan cover 71a, and a cushion bracket 78 is further fixed to the muffler support bracket 77.

A pivot 81 and a rear frame at substantially the same height as the lower portion of the crankcase 71 of the cushion bracket 78 are provided.
A shock absorber 80 is interposed between the 65 and the pivot 82 at the upper part of the inclined portion. Since the pivot 81 is located below, the shock absorber 80
It crosses the right side of the crankcase 71 diagonally with an inclination of 5 degrees.

A frame pivot 67 for swingably supporting the power unit 70 is provided below the rear frame 65,
The shock absorber 80 is separated from the pivot portion (axis 82) to the rear frame 65, and the other end of the shock absorber 80 to the power unit 70 (axis 81) is located below, so that the rear frame 65 The compression stroke of the shock absorber 80 itself can be increased while keeping the horizontal portion 65b low.

Transmission case and rear wheel arranged on left side of vehicle body
By arranging the shock absorber 50 on the right side of the vehicle body on the opposite side with respect to 85, it is possible to minimize the deviation of the weight to one side in the vehicle body width direction, and to reduce the difference between the left and right weights. Since the link mechanism is not configured, the number of parts can be reduced and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall left side view of a scooter type motorcycle according to one embodiment of the present invention.

FIG. 2 is a right side view of the main part.

FIG. 3 is a top view in which a part of the same portion is omitted.

FIG. 4 is a perspective view of a main part showing a link mechanism.

FIG. 5 is an explanatory diagram for explaining movement of a link mechanism.

FIG. 6 is a right side view of a main portion of a scooter type motorcycle according to another embodiment.

FIG. 7 is a left side view of a main part of a conventional scooter type motorcycle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scooter type motorcycle, 2 ... Head pipe, 3 ... Front frame, 4 ... Horizontal frame, 5 ... Rear frame, 6
... luggage box, 7 ... carrier, 10 ... handle,
11 ... steering shaft, 12 ... front fork, 13
... front wheel, 15 ... frame pivot, 16 ... engine hanger link, 17 ... engine pivot, 20 ... power unit, 21 ... unit swing case, 22 ... crankcase, 23 ... transmission case, 24 ... hanger bracket, 25 ... internal combustion engine, 26 … Intake pipe, 27… carburetor, 28… air cleaner,
29 ... rear wheel, 30 ... exhaust pipe, 31 ... muffler, 32 ... muffler support bracket, 33 ... link support bracket, 34 ... bolt, 35 ... fuel tank, 40 ... cushion arm, 41, 42 ...
Axis, 43… Cushion connecting rod, 44… Axis, 45, 46…
Bracket, 47, 48 Axis, 50 Shock absorber, 61 Scooter type motorcycle, 63 Front frame, 64 Horizontal frame,
65 ... rear frame, 66 ... bracket, 67 ... frame pivot, 70 ... power unit, 71 ... crankcase, 72 ...
Engine hanger, 73 ... engine pivot, 75 ... engine hanger link, 76 ... muffler, 77 ... muffler support bracket, 78 ... cushion bracket, 80 ... shock absorber, 8
1, 82 ... Axis, 85 ... Rear wheel.

Claims (2)

[Claims] 1. A motorcycle having an internal combustion engine body integrally provided at a front portion of a transmission case having a built-in transmission mechanism, and a power unit supporting a rear wheel pivotally supported at a rear portion thereof so as to be swingable with respect to a vehicle body frame. A rear wheel suspension device for a motorcycle, wherein a shock absorber interposed between the vehicle body frame and the power unit is provided on the opposite side of the transmission case and the rear wheel. An internal combustion engine body is integrally provided at a front portion of a transmission case having a built-in transmission mechanism, and a power unit which supports a rear wheel at a rear portion is swingably supported by a body frame via a pivot. A rear wheel suspension system for a motorcycle, comprising: a first link member pivotally supported on a side opposite to the transmission case of the power unit and a rear wheel between the transmission case and the power unit; A shock absorber having one end pivotally connected near the pivot to be pivoted and the other end pivotally connected to one side of the first link member; and the other end pivotally connected to the other side of the first link member while one end is pivotally connected to the body frame. A rear wheel suspension device for a motorcycle, comprising: a second link member attached to the motorcycle.