JPH03292277A - Rear wheel suspension device for motorcycle - Google Patents

Abstract

PURPOSE:To simplify and facilitate structure and mounting and to improve riding sensation by providing a damping force regulating member capable of regulating the damping force of a damping force generating device and an oil pressure transmitting device to transmit axial displacement of a buffer to the damping force regulating member by means of an oil pressure. CONSTITUTION:When, during running of a vehicle, an up load is exerted on a rear wheel from a road surface, a rear arm 7 is rocked upward against the energizing force of a suspension spring 16, whereby a cylinder 13 of a buffer 12 is contracted. In which case, since a moving amount detecting piston 23 is relatively moved downward within a hydraulic cylinder 20 and a regulating piston 18 is moved upward through the action of working oil 24. Through upward movement of a damping force regulating member 17, a damping force in a damping force generating device is changed. In the damping force, with the increase in an upward moving amount of the rear arm 7, i.e. the stroke of the buffer 12, a moving amount of the regulating piston 18, i.e. the damping force regulating member 17, is increased and a damping force in the damping force generating device is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rear wheel suspension system disposed between a motorcycle body and a rear arm.

[Prior Art] A rear wheel suspension system for a motorcycle is required to have a progressive characteristic in which the impact force is weak at the beginning and rebounds with a stronger force as a stronger force is applied.

For example, in Japanese Patent Application Laid-Open No. 61-1259013,
The reaction is provided with an adjustment member that can adjust the damping force generated by the damping force generator by axial displacement, and a link mechanism is provided between the adjustment member and the rear arm, and the adjustment member is axially moved in response to the rocking of the rear arm. A method has been proposed in which interlocking is performed so as to cause directional displacement.

[Problems to be Solved by the Invention] In recent years, the demand for improving the ride comfort of vehicles has become stronger, but in the above-mentioned conventional rear wheel suspension system,
Since a link mechanism is provided between the adjustment member and the rear arm, the structure and installation are complicated, and the durability against mud and dust is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a rear wheel suspension system for a motorcycle that is simple in structure and installation, and can improve riding comfort.

[1! Means for Solving the Problem] To achieve this, the rear wheel suspension system for a motorcycle according to the present invention includes a shock absorber 12 equipped with a damping force generating device inside the vehicle body frame 2.
and a rear arm 7 that is pivotally supported by the vehicle body frame 2, the damping force adjusting member 17 that makes it possible to adjust the damping force of the damping force generating device, and the shock absorber 12.
The damping force adjusting member 17 is characterized by having a hydraulic transmission device that transmits the axial displacement of the damping force adjusting member 17 by hydraulic pressure.

Note that the numbers added to the above configurations are for comparison with the drawings, and the configurations of the present invention are not limited thereby.

[Function] In the present invention, as shown in FIG. 1, for example, when the rear wheel 8 receives an upward load from the road surface while the vehicle is running, the rear arm 7 moves upward against the biasing force of the suspension spring 16. A movement detection piston 2 fixed to a cylinder 13 for swinging.
3 relatively moves downward within the second hydraulic cylinder 20,
Since the adjustment piston 18 moves upward due to the action of the hydraulic oil 24, the upward movement of the damping force adjustment member 17 causes
Change the damping force in the damping force generator.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 shows a side view of the rear wheel side of the motorcycle according to the present invention. ing. Further, a pair of left and right rear arms 7 are supported on the vehicle body frame 2 so as to be able to swing up and down by a rotation shaft 6, and a rear wheel 8 is rotatably supported on the rear arms 7.

Further, a bracket 8 is fixed to the rear arm 7, and a shock absorber 12 is disposed between a pivot shaft 10 provided on the bracket 9 and a pivot shaft 11 provided on the vehicle body frame 2.

FIG. 1 shows a rear wheel suspension system for a motorcycle according to the present invention.
FIG. 3 is an enlarged sectional view showing an example.

The buffer 12 has a cylinder 13 filled with buffer oil,
The cylinder 13 has a piston, an orifice, etc. (not shown), and is provided with a well-known damping force generating device. Further, a shock absorber 12 is connected to the piston and is connected to the cylinder 1.
3, a lower mounting plate 15 fixed to the lower end of the piston rod 14, and a shock absorber 12 disposed between the lower mounting plate 15 and the cylinder 13.
A lower mounting plate 15 is swingably connected to the rear arm 7 via a pivot shaft 10.

In this embodiment, a rod-shaped damping force adjusting member 17 is slidably disposed within the piston rod 14, an adjusting piston 18 is integrally formed at the lower end of the damping force adjusting member 17, and further, An adjusting piston 18 is fitted within the first hydraulic cylinder 18 . This adjustment piston 18 is configured to be biased downward by a spring (not shown).

Further, first and second hydraulic cylinders 19 and 20 are fixedly attached to the lower mounting plate 15, and the first and second hydraulic cylinders 19 and 20 are connected by a hydraulic hose 21. Furthermore, an auxiliary cylinder 22 is provided at the lower end of the cylinder 13.
The movement detection piston 23 is fixed, the second hydraulic cylinder 20 is slidably fitted into the auxiliary cylinder 22, and the movement detection piston 23 is fitted into the second hydraulic cylinder 20. Ru. Then, hydraulic oil 24 is sealed between the adjustment piston 18 and the movement amount detection piston 23,
It constitutes a hydraulic transmission device.

The operation of the present invention having the above configuration will be explained. When the rear wheel 8 receives an upward load from the road surface while the vehicle is running, the rear arm 7 swings upward against the biasing force of the suspension spring 16, so that the cylinder 13 of the shock absorber 12 contracts. Therefore, the movement detection piston 23 relatively moves downward within the second hydraulic cylinder 20, and the adjustment piston 18 moves upward due to the action of the hydraulic oil 24, so that the upward movement of the damping force adjustment member 17 causes the adjustment piston 18 to move upward. , changing the damping force in the damping force generator described above.

As the amount of upward swinging of the rear arm 7, that is, the stroke of the shock absorber 12 increases, the damping force increases as the amount of movement of the adjustment piston 18, that is, the damping force adjustment member 17 increases, as shown by line A in FIG. Increase the damping force in the damping force generator.

Note that by changing the ratio of the pressure-receiving areas of the adjustment piston 18 and the movement amount detection piston 23, the amount of axial displacement of the first adjustment piston can be freely set.

FIG. 3 shows another embodiment of the invention, in which a cam mechanism 26 is connected via a link 25 to an adjusting piston 18 that fits within a first hydraulic cylinder 19 fixed to a lower mounting plate 15; The lower end of the damping force adjusting member 17 is brought into contact with the cam surface 26a of the cam mechanism 26. The rotation shaft 26b of the cam mechanism 26 is provided on a bracket (not shown) fixed to the lower mounting plate 15. Therefore, when the adjusting piston 18 moves as shown in FIG. It will move upward by the amount of movement shown by line B in FIG. 2, and will have progressive characteristics.

4 and 5 show still other embodiments of the invention. In the figure, reference numeral 27 denotes a hydraulic transmission device that includes the first and second hydraulic cylinders 18 and 20 described in FIG. 1 and a flexible hydraulic hose 21, and is attached to the vehicle body frame 2.

In the embodiment shown in FIG. 4, a detection boss 28 is fixed to the side wall of the shock absorber 12, and the swinging of the shock absorber 12 is detected by the movement detection piston 28 explained in FIG.
and the adjustment piston 18. In addition, in the embodiment shown in FIG.
8 to the movement amount detection piston 23 and the adjustment piston 18 described in FIG.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made.

For example, one end of the hydraulic transmission device may be disposed on the front fork, and the adjustment piston may be moved by sensing the stroke of the front fork. Further, the hydraulic transmission device may be operated in conjunction with the movement of a rear pedal brake, a front brake lever, or a separately provided manual lever.

Further, in the above embodiment, the damping force adjusting member 17 is disposed within the piston rod 14, but it may be disposed at any location.

[Effects of the Invention] As explained above, according to the present invention, since the axial displacement of the shock absorber is transmitted to the damping force adjustment member by hydraulic pressure, the structure and installation are simple and easy, and piping can be freely connected from any location. It is possible to improve riding comfort. In addition, it is resistant to mud, dust, etc., and its durability can be improved.

[Brief explanation of drawings]

FIG. 1 shows a rear wheel suspension system for a motorcycle according to the present invention.
FIG. 2 is a diagram for explaining the present invention in detail; FIGS. 3, 4, and 5 are schematic diagrams showing other embodiments of the present invention; FIG. 6 is an enlarged sectional view showing an embodiment; 1 is a side view of the rear wheel side of the motorcycle according to the present invention. 2...Vehicle frame, 7...Rear arm, 12...
- Shock absorber, 17... Damping force adjustment member, 18... Adjustment piston, 23... Travel amount detection piston.

Claims (1)

[Claims] (1) In a motorcycle in which a shock absorber equipped with a damping force generating device inside is arranged between a body frame and a rear arm pivotally supported by the body frame, the damping force of the damping force generating device can be adjusted. A rear wheel suspension system for a motorcycle, comprising: a damping force adjusting member; and a hydraulic transmission device that transmits axial displacement of the shock absorber to the damping force adjusting member using hydraulic pressure.