JPH02197488A - Rear arm device for motorcycle - Google Patents

Abstract

PURPOSE:To simplify a structure in the reverse direction displacement of a rear wheel by forming in a rear arm a rear wheel supporting forked arm bending its arm part to the upper for the base part so as to displace the rear wheel in a reverse direction to the turn direction. CONSTITUTION:A rear arm 8 is constituted of a rear arm base part 8a pivotally supported turnably to a main frame by a pivot 23 and arm members 8b, 8c supporting a rear wheel 9 and branching from the base part 8a. The arm members 8b, 8c are bent to the upper. By this constitution, for a front wheel turning, moment in the direction of an arrow head acts on the arm members 8b, 8c displaces the rear wheel in a reverse direction. Thus, the rear wheel can be easily displaced conversely to the turning direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rear arm device for displacing a rear wheel of a motorcycle in a direction opposite to a turning direction when the vehicle body is tilted around a curve.

[Conventional technology]

As shown in Fig. 3(a), when a motorcycle tilts its body around 1 on a curve and steers the front wheel 5, if the rear wheel 9 is displaced in the opposite direction to the turning direction, the same turning radius can be achieved. On the other hand, it is possible to turn with a smaller bank angle (inclination angle) than before.

To this end, in Japanese Patent Application No. 61-81002, the steering angle of the front wheels, the angle of inclination of the vehicle body, and the vehicle speed are detected, and a servo motor is driven by an electronic control device according to these values. A method for controlling the steering angle of the wheels has been proposed.

[Problem to be solved by the invention]

However, the conventional system described above requires detection means for detecting the steering angle of the front wheels, the tilt angle of the vehicle body, and the vehicle speed, and has the problem of requiring a complicated electronic control device.

An object of the present invention is to solve the above problem, and is a rear arm device capable of displacing the rear wheel in a direction opposite to the turning direction with a simple structure in which the rear arm member is provided with mechanical deformation means. The purpose is to provide

[Means to solve the problem]

In order to solve the above problem, the invention described in claim 1 includes a front wheel 5 supported by a vehicle body frame 2 via a front fork 4, and a rear arm 8 rotatably supported by the vehicle body frame 2. , and a rear wheel 9 supported by the rear arm 8, the rear arm 8 includes a rear arm base 8a, and arm members 8b and 8c branching from the rear arm base 8a and supporting the rear wheel 9. The arm member 8 b s 8 c is formed to be bent upward with respect to the rear arm base 8 a, and is characterized in that it allows the rear wheel 9 to be displaced in a direction opposite to the turning direction.

Further, the invention described in claim 2 includes a front wheel 5 supported by the vehicle body frame 2 via a front fork 4, a rear arm 8 rotatably supported by the vehicle body frame 2, and a front wheel 5 supported by the vehicle body frame 2 via a front fork 4; In a motorcycle 1 having a supported rear wheel 9, the rear arm 8 has a rear arm base 8.
a, and arm members 8b and 8c that branch from the rear arm base 8a and support the rear wheel 9, and a support block body 26 that is inserted into the arm members 8b and 8c.
The support block body 26 has a long hole 27 formed in an oblique direction, and an elastic body 29 that is fitted into the long hole 27. The wheel shaft 25 of the rear wheel 9 is inserted into the elastic body 29. It is characterized by allowing the rear wheel 9 to be displaced in a direction opposite to the turning direction.

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

[Effect]

In the invention according to claim 1, when the vehicle body is tilted at a curve and steered to the right, as shown in FIGS. 1 and 2, for example, the arm member 8b moves in an upward arc around the bending point 8d. On the other hand, the arm member 8
Since c deforms downward into a circular arc, it is possible to displace the rear wheel 9 by the steering angle θ in a direction opposite to the turning direction.

Further, in the invention according to claim 2, as shown in FIG. 3, both ends of the wheel shaft 25 are provided with elastic bodies 29
Since the rear wheel 9 is displaced obliquely upward or obliquely downward along the elongated hole 27, the rear wheel 9 can be similarly displaced by the steering angle θ in the direction opposite to the turning direction.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 shows an overall side view of a motorcycle to which the present invention is applied. A front fork 4 is rotatably supported on a head vibrator 3 constituting a body frame 2 of the motorcycle 1, and a front fork 4 is supported at the bottom thereof. 5 is provided, and a handle 6 is provided at the top. Further, a rear arm 8 is rotatably supported at the rear of the main frame 7 extending rearward from the head pipe 3, and a rear wheel 9 is supported on this.
On the other hand, the upper part of the main frame 7 is covered with a fuel tank 10. Furthermore, the rear of the main frame 7 L;! A seat T-rail 11 is connected, and a seat 12 is provided on the seat rail 11.

An engine 14 is mounted between the down tube 13 extending downward from the front end of the main frame 7 and the main frame 7. A carburetor 17 and an air cleaner 18 are connected to a cylinder 15 that constitutes the engine I4. , an exhaust system 19 extends from the front side of the cylinder 15 through the lower part of the vehicle body, extends rearward, and is connected to a muffler 22 . The front and both sides of the motorcycle 1 are covered with a cowling 21, and the radiator 20 is cooled by introducing running air through the front opening of the cowling 21.

1 and 2 show one embodiment of the rear arm device of the present invention, FIG. 1 is a plan view, FIG. 2(a) is a side view of FIG. 1, and FIG. 2(b) is a rear arm device. It is a diagram seen from the rear.

The rear arm 8 consists of a rear arm base 8a rotatably supported on the main frame 7 by a pivot 23, and arm members 8b and 8C that branch from the rear arm base 8a and support the rear wheel 9. , 8c is
The bending point 8d with respect to the rear arm base 8a (Fig. 2(a)
) is bent upward.

The operation of the rear arm device having the above configuration will be explained.

As shown in FIG. 3(a), if we consider the case where the vehicle body is tilted at a curve and the front wheels 5 are steered to the right, the rear wheels 9 are tilted to the right as shown in FIG. 3(b). Therefore, a moment in the direction of the arrow acts on the arm members 8b and 8c.

Therefore, as shown by the dotted lines in FIGS. 2(a) and 2(b), the arm member 8b draws an arc upward with the bending point 8d as the center (
On the other hand, the arm member 8C deforms in a downward arc around the bending point 8d. the result,
As shown by the dotted line in FIG. 1, the rear wheels 9 can be displaced by a steering angle θ in a direction opposite to the turning direction. Note that when steering to the left, the above effect is reversed.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4(a) is a sectional view of the arm member, and FIG. 4(b) is a sectional view taken along line bb in the previous figure.

A support block body 26 for supporting the wheel shaft 25 of the rear wheel 9 is inserted into the arm member 8b (8c) and fixed with a bolt 30. A long hole 27 is formed in the support block body 26 in an oblique direction, and an elastic body 29 is fitted into the long hole 27. After fitting the washer 31 and collar 32 to the wheel shaft 25, the wheel shaft 25 is passed through the elastic body 29,
The elastic body 29 is tightened and fixed by a washer 33 and a nut 35.

To explain the operation of the rear arm device having the above configuration, as described above, when making a curve, the arm member 8b,
A force in an upside down direction acts on 8C. Therefore, both ends of the wheel shaft 25 are displaced against the elastic body 29, and are displaced diagonally upward or downward along the elongated hole 27. As a result, as shown by the dotted line in FIG. 1, the rear wheels 9 can be displaced by the steering angle θ in a direction opposite to the turning direction.

[Effects of the Invention] As described above, according to the present invention, the rear wheel can be displaced in the direction opposite to the turning direction with a simple structure in which the rear arm member is provided with a mechanical deformation means.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the glue/ear arm device of the present invention, FIG. 1 is a plan view, FIG. 2(a) is a side view of FIG. 1, and FIG. 2(b) is a rear arm device. View from the rear,
Figure 3 is a schematic diagram for explaining the action when the vehicle body curves, Figure 4 (a) is a sectional view of the arm member, Figure 4 (b)
) is a sectional view taken along b-bvA in the previous figure, and FIG. 5 is an overall side view of a motorcycle to which the present invention is applied. l...Motorcycle, 2...Body frame, 4...
Front fork, 5...Front wheel, 8...Rear arm, 8a...Rear arm base, 8b, 8C...Arm member, 9...Rear wheel, 25...Wheel shaft, 2
6... Support block body, 27... Long hole, 29...
Elastic body. Patent applicant Yamaha Motor Co., Ltd. Representative Patent Attorney
Hiroki Shirai (5 others) Figure 1 Figure 2 Figure 3 (a) (b) Figure 4 (a) Figure 4 (b)

Claims (2)

[Claims] (1) In a motorcycle having a front wheel supported on a body frame via a front fork, a rear arm rotatably supported on the body frame, and a rear wheel supported on the rear arm, the rear arm is , consisting of a rear arm base and an arm member that branches from the rear arm base and supports the rear wheel, and the arm member is bent upward with respect to the rear arm base and rotates the rear wheel in a direction opposite to the turning direction. A rear arm device for a motorcycle, characterized in that the rear arm device is capable of displacing the rear arm of a motorcycle. (2) In a motorcycle having a front wheel supported on a body frame via a front fork, a rear arm rotatably supported on the body frame, and a rear wheel supported on the rear arm, the rear arm is , consisting of a rear arm base, and an arm member branching from the rear arm base to support the rear wheel, further comprising a support block body inserted into the arm member, and a length formed diagonally on the support block body. It has a hole and an elastic body fitted into the elongated hole, and the wheel shaft of the rear wheel is fixed through the elastic body, so that the rear wheel can be displaced in a direction opposite to the turning direction. Rear arm device for motorcycles.