JPH06183386A - Rear wheel suspension device for motorcycle - Google Patents

Abstract

PURPOSE:To improve the parts layout of a body and attain low center-of- gravity, and at the same time, transmit the damping force of a rotary damper to a swing arm unforcibly so as to prevent torsion and make rotation smooth. CONSTITUTION:A backward extended swing arm 19 is rotatably fixed to a pivot 18 erected in the body width direction on a body frame 2, and a rear wheel 20 is journalled to the free end part of the swing arm 19. A motorcycle 1 of such constitution is provided with a rotary damper 48 formed being provided with a damper shaft 49 formed into shaft shape and a damper body 51 rotatable with damping resistance around the damper shaft 49. The damper shaft 49 is placed parallel to the pivot 18 and fixed at both ends to the body frame 2. A damper bracket 59, a swing arm bracket 60 and a link 61 are further provided to convert the rotation of the swing arm 19 into the rotation of the damper body 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel suspension system for a motorcycle which uses a rotary rotary damper instead of a telescopic damper.

[0002]

2. Description of the Related Art In a general motorcycle, a pivot shaft extending in the vehicle width direction is mounted on a vehicle body frame, and a swing arm extending rearward is rotatably attached to the pivot shaft. The body layout is such that the rear wheel is pivotally supported at the free end (rear end).

A rear wheel suspension device (suspension device) is provided between the swing arm and the body frame.
The swing shock of the swing arm due to the vertical movement of the rear wheel is attenuated, and the position of the swing arm is restored.

As a rear wheel suspension system of a motorcycle, a mainstream system in recent years is one in which a shock absorber, which is a combination of a coil spring and a hydraulic damper, is connected to a vehicle body frame and the other end is connected via a link or the like. Is connected to the base end of the swing arm.

However, in the case of such a rear wheel suspension system, since the shock absorber, which is a relatively large component, is arranged in the central portion of the vehicle body, great restrictions are placed on the component layout of the vehicle body and at the same time, There was a difficulty that the center of gravity of the robot would become high.

Therefore, a rear wheel suspension system using a rotary damper instead of the shock absorber has been proposed. As shown in FIG. 6, the rotary damper 100 includes a damper shaft 101 formed in an axial shape, and a damper body 102 rotatable around the damper shaft 101 with damping resistance. In the related art, one in which one end of the damper shaft 101 projects from one side of the damper body 102 is used in the related art.
02 is fixed to the body frame side and the damper shaft 10
The layout is such that the first protruding portion is connected to the swing arm 105 via the links 103, 104 and the like.

In this case, as the swing arm 105 rotates about the pivot shaft 106 as a fulcrum, the damper shaft 1
01 is rotated and a damping resistance is generated when the damper shaft 101 rotates in the damper body 102, so that the swinging shock of the swing arm 105 is buffered by the damping resistance.

In such a rear wheel suspension system, the rotary damper 100 can be made compact and lightweight, and since the rotary damper 100 can be installed below the vehicle body, the layout layout of the vehicle body is improved and the center of gravity of the vehicle body is lowered. Can contribute to realization.

[0009]

However, in the conventional rear wheel suspension system using the rotary damper 100, the damping force of the rotary damper 100 is applied only to one side (the left side in FIG. 6) of the swing arm 105. 105 was in a twisted state.

For this reason, the swing arm 105 is difficult to rotate smoothly and is not practical, and it is necessary to reinforce the swing arm 105 in order to secure rigidity against twisting.
There was a concern that the manufacturing cost would increase as the weight of No. 5 increased.

The present invention has been made in view of the above problems, and improves the parts layout of the vehicle body and lowers the center of gravity by using the rotary damper, and at the same time transmits the damping force of the rotary damper to the swing arm without difficulty. It is an object of the present invention to provide a rear wheel suspension device for a motorcycle that can prevent the swing arm from twisting and can smoothly rotate the swing arm.

[0012]

In order to achieve the above object, a rear wheel suspension system for a motorcycle according to the present invention includes a swing shaft extending rearward on a pivot shaft provided in a vehicle body frame in a vehicle width direction. In a motorcycle in which a rear wheel is pivotally rotatably supported and a rear wheel is pivotally supported at a free end of the swing arm, a damper shaft formed in an axial shape and a damping resistance around the damper shaft are provided. A rotary damper having a rotatable damper body is provided on a vehicle body frame, and both ends of the damper shaft are fixed to the vehicle body frame by making the damper shaft of the rotary damper parallel to the pivot axis and a swing arm. Damping force transmitting means for converting the rotation of the swing arm into the rotation of the damper body is provided between the center portion in the left-right direction of the vehicle and the damper body. It is intended to.

[0013]

With this structure, since the damping force of the rotary damper is applied to the center portion of the swing arm in the left-right direction via the damping force transmitting means, there is no risk of excessive twisting of the swing arm, and the swing arm is prevented. The rotation of is very smooth. Therefore, it is not necessary to reinforce the swing arm as a countermeasure against twisting, and it is possible to avoid an increase in the weight and cost of the swing arm.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a left side view of a motorcycle to which the present invention is applied. The motorcycle 1 is provided with, for example, a diamond-shaped vehicle body frame 2, and the vehicle body frame 2 includes a head pipe 3 located in the forehead and a pair of left and right extending from the head pipe 3 obliquely rearward and downward. The main pipe 4, an engine supporter 5 provided over the head pipe 3 and the main pipe 4, a pair of left and right center plates 6 fixed to the rear end of the main pipe 4, an intermediate portion of the main pipe 4, and a rear portion. It has a pair of left and right seat rails 7 and a seat stay 8 that extend obliquely rearward and upward from the ends. The left and right members 4, 6, 7, 8 are connected to each other by a bridge member (not shown) extending in the vehicle width direction.

Below the main pipe 4, the engine 1 is provided.
0 is suspended. The engine 10 is supported by being bolted to the engine supporter 5 and the center plate 6. In addition, 11 is a radiator and 12 is an exhaust muffler. A fuel tank 13 is provided on the main pipe 4.
The seating seat 14 located at the rear of the fuel tank 13 is mounted on the seat rail 7.

A front fork 16 supporting a front wheel 15 is pivotally attached to the head pipe 3 together with a handle bar 17 so as to be rotatable left and right. On the other hand, a swing arm 19 extending rearward is pivotally attached to a pivot shaft 18 provided in the center plate 6 in the vehicle width direction so as to be vertically rotatable, and a rear wheel 20 is axially supported at a free end of the swing arm 19. ing. The rear wheel 20 is driven by the engine 10 via a chain 21.

The rear end of the swing arm 19 is provided with a rear wheel suspension device 23 according to the present invention. FIG. 2 is a left side view showing the detailed structure of the rear wheel suspension device 23,
FIG. 3 is a sectional view developed along the line III-III in FIG. Further, FIG. 4 shows an embodiment of the present invention.
FIG. 4 is a sectional view developed along line IV-IV in FIG.

As shown in FIG. 2, the swing arm 19 is formed by connecting a pair of left and right arm members 24, 24 sandwiching the rear wheel 20 by a bridge member 25, and has a substantially H-shaped planar shape.

The rear wheel suspension device 23 is a device in which a restoring mechanism 26 using a torsion bar and a buffer mechanism 27 using a rotary damper are combined. First, the configuration of the restoration mechanism 26 will be described.

A torsion bar bracket 29 extending in the vehicle width direction is fixed to the lowermost portion between the left and right center plates 6 and 6 by welding or the like. The torsion bar bracket 29 is provided with three supporting arms 30, 31, 32 protruding from the supporting arm 30, 31, 32.
A torsion bar 33 is installed so as to be parallel to the pivot shaft 18.

The central portion of the torsion bar 33 is fixed to the vehicle body frame 2 by fitting the central support arm 31 with a spline 34 or the like. Further, the journal portion 3 is provided near the left and right ends of the torsion bar 33.
5, 35 are formed, and these journal parts 35, 35 are formed.
Bearings 3 on the left and right support arms 30 and 32, respectively.
Since the torsion bar 33 is supported via the rollers 6, 36, both ends of the torsion bar 33 can be twisted with respect to the center within its elastic range. Both ends of the torsion bar 33 project laterally from the left and right support arms 30 and 32, and splines 37 and 37 are formed on the projecting portions.

Torque transmission means 39 is provided between both ends of the torsion bar 33 having the splines 37, 37 and the left and right sides of the swing arm 19. The torque transmission means 39 twists both ends of the torsion bar 33 in accordance with the rotation of the swing arm 19, and a pair of left and right torque arms 40, 40 spline-coupled to both ends of the torsion bar 33 in a rotationally integrated manner.
And a pair of left and right torque rods 41, 41, one end of which is pivotally attached to the torque arms 40, 40, and the swing arm 1.
9, a pair of left and right torque brackets 42, 42 fixed to the lower surfaces of the bridge members 24, 24 for pivotally attaching the other ends of the torque rods 41, 41.

The torque arms 40, 40 are fitted to the splines 37, 37 of the torsion bar 33 in a posture substantially parallel to the swing arm 19, and the bolt 4
It is fastened to the torsion bar 33 by 3. Further, the torque rods 41, 41 extend substantially at right angles from the lower surface of the swing arm 19 and are connected to the torque arms 40, 40. The bolts 44 are respectively provided between the torque arms 40, 40 and the torque rods 41, 41 and between the torque rods 41, 41 and the torque brackets 42, 42.
It is rotatably connected by such means.

Next, the buffer mechanism 27 will be described.

As shown in FIGS. 2 and 4, a pair of left and right damper stays 4 are provided inside the left and right center plates 6 and 6.
6, 46 are fixed by bolts 47 and the like, and a rotary damper 48 has a central axis between the damper stays 46, 46 and the pivot shaft 18 and the torsion bar 33.
It is supported to be parallel to.

The rotary damper 48 includes a shaft-shaped damper shaft 49 fixed to the damper stays 46, 46 by spline coupling or the like, and the damper shaft 4.
9 is supported on the outside of the bearing 9 through bearings 50, 50, etc.
It has a cylindrical damper body 51 that is rotatable around the damper shaft 49 with damping resistance.

FIG. 5 is a sectional view taken along line VV of FIG.
2 shows a conceptual internal structure of the rotary damper 48. An oil chamber 52 is formed in the damper body 51, and oil is filled in the oil chamber 52.

On the inner wall of the damper body 51, a movable partition plate 53 extending toward the damper shaft 49 is provided, for example, 4
The sheets are projected at equal angular intervals. A gap 54 is formed between the free ends of the movable partition plates 53 and the peripheral surface of the damper shaft 49.

On the other hand, on the peripheral surface of the damper shaft 49, fixed partition plates 55 alternately sandwiched between the movable partition plates 53 are radially provided. A gap 56 is formed between the free ends of these fixed partition plates 55 and the inner wall of the damper body 51.

A damping force transmission means 58 for converting the rotation of the swing arm 19 into the rotation of the damper body 51 is provided between the center of the swing arm 19 in the left-right direction and the damper body 51. . The damping force transmitting means 58 includes, for example, a damper bracket 59 provided on the outer peripheral surface of the damper body 51 and a swing arm bracket provided on the lower surface of the bridge member 25 provided on the swing arm 19 in the left-right center. 60 and a link 61 that connects the brackets 59 and 60. The brackets 59 and 60 and the link 61 are rotatably connected by a bolt 62 or the like.

Rear wheel suspension device 23 constructed as described above
Works as follows.

When the rear wheel 20 moves up and down due to the unevenness of the road surface and the swing arm 19 rotates about the pivot shaft 18 while the motorcycle 1 is running, the swing torque of the swing arm 19 is left and right. It is evenly transmitted to both ends of the torsion bar 33 by the rods 41, 41 and the torque arms 40, 40. As described above, the central portion of the torsion bar 33 is fixed to the vehicle body frame 2, and both end portions of the torsion bar 33 are supported so as to be twistable within the elastic range with respect to the central portion. When transmitted to both ends of the bar 33, both ends of the torsion bar 33 are twisted in the same direction with respect to the center.

When the torsion of the torsion bar 33 is restored to the torsion at both ends, the restoring torque is evenly applied to the left and right sides of the swing arm 19 via the torque arms 40, 40 and the torque rods 41, 41. The rotation of the swing arm 19 is restored.

Further, the rotation of the swing arm 19 is transmitted to the damper body 51 of the rotary damper 48 via the damping force transmitting means 58 to rotate the damper body 51 around the damper shaft 49. As a result, the movable partition plate 53 provided on the damper body 51 side rotates between the fixed partition plates 55 provided on the damper shaft 49 side,
The oil in the oil chamber 52 is caused to flow between the partition plates 53 and 55. Then, the flow resistance when the oil passes through the gaps 54 and 56 becomes a damping force against the rotation of the damper body 51, and this damping force is transmitted to the swing arm 19 via the damping force transmission means 58, and the swing arm 19 moves. A sudden turning shock is buffered.

In this way, the rotation of the swing arm 19 when the motorcycle 1 is traveling is restored and buffered, and a good ride comfort is provided.

The rear wheel suspension device 23 configured as described above
Since the restoration mechanism 26 using the torsion bar 33 and the buffer mechanism 27 using the rotary damper 48 can be made compact and lightweight, and the entire device can be installed below the vehicle body, It is possible to improve the component layout of the two-wheeled vehicle 1, lower the center of gravity, and further reduce the weight.

According to the present invention, the rotary damper 4
Since the damping force of No. 8 is applied to the central portion in the left-right direction of the swing arm 19 by the damping force transmitting means 58, the swing arm 19 is prevented from being unduly twisted, and the swing arm 19 rotates very smoothly. Will be things. Therefore, it is not necessary to reinforce the swing arm 19 as a countermeasure against twisting as in the related art, and it is possible to avoid an increase in the weight and cost of the swing arm 19.

The restoring mechanism 26 does not necessarily have to use the torsion bar 33, and may have another type using, for example, a coil spring or a leaf spring.

[0040]

As described above, in the rear wheel suspension system for a motorcycle according to the present invention, the swing arm extending rearward is rotatably pivoted on the pivot shaft provided in the vehicle body frame in the vehicle width direction. In a motorcycle in which the rear wheel is attached to the free end portion of the swing arm, the damper shaft formed in an axial shape and rotatable around the damper shaft can be rotated with damping resistance. A rotary damper having a damper body is provided on the vehicle body frame, and both ends of the damper shaft are fixed to the vehicle body frame by aligning the damper shaft of the rotary damper with the pivot axis, and a central portion of the swing arm in the left-right direction. The damping force transmitting means for converting the rotation of the swing arm into the rotation of the damper body is provided between the damper body and the damper body.

Therefore, since the damping force of the rotary damper is applied to the central portion in the left-right direction of the swing arm via the damping force transmitting means, there is no possibility of unreasonable twisting of the swing arm, and the swing arm rotates extremely. Becomes smooth. Therefore, it is not necessary to reinforce the swing arm as a countermeasure against twisting, and it is possible to avoid an increase in the weight and cost of the swing arm.

[Brief description of drawings]

FIG. 1 is a left side view of a motorcycle to which the present invention is applied.

FIG. 2 is a left side view showing the detailed structure of the rear wheel suspension device.

FIG. 3 is a sectional view developed along line III-III in FIG.

FIG. 4 shows an embodiment of the present invention and is taken along line IV-IV of FIG.
Sectional drawing developed along the line.

5 is a cross-sectional view taken along the line VV of FIG.

FIG. 6 is a perspective view of a rear wheel suspension device showing a conventional technique.

[Explanation of symbols]

 1 Motorcycle 2 Vehicle Body Frame 18 Hippot Shaft 19 Swing Arm 20 Rear Wheel 23 Rear Wheel Suspension 46 Damper Stay 48 Rotary Damper 49 Damper Shaft 51 Damper Body 58 Damping Force Transmission Means 59 Damper Bracket 60 Swing Arm Bracket 61 Link 62 Bolt

Claims (1)

[Claims] 1. A two-wheel automatic vehicle in which a swing arm extending rearward is rotatably and pivotally attached to a pivot shaft provided in a vehicle body frame in a vehicle width direction, and a rear wheel is pivotally supported at a free end of the swing arm. In a vehicle, a vehicle body frame is provided with a rotary damper having a damper shaft formed in an axial shape and a damper body rotatable around the damper shaft with damping resistance. Both ends of the damper shaft are fixed to the vehicle body frame by making the damper shaft parallel to the pivot axis, and the rotation of the swing arm is converted into the rotation of the damper body between the center part of the swing arm in the left-right direction and the damper body. Automatic 2 characterized by having damping force transmitting means for
Rear wheel suspension system for wheeled vehicles.