JPH0299481A - Front and rear wheel steering device for motor bicycle - Google Patents

Abstract

PURPOSE:To simplify steering of rear wheels by a method wherein a rear arm for supporting rear wheels is pivotally supported to a bracket supported to a car body frame through a resilient member, and the resilient main shaft of a resilient member is inclined based on the central axis in the longitudinal direction of a car body. CONSTITUTION:A bracket 8 is supported to a rear bracket 7 of a car body frame through a resilient member. A rear arm 9 is pivotally supported to the rear part of the bracket 8 by means of a bolt 11. Rear wheels 12 are rotatably supported to the rear end part of the rear arm 9. In this case, a cylinder part 17 of the bracket 8 has a radial central line the extension line of which crosses a longitudinal central line CL on a point (a) thereon, and is supported through a cylinder rubber 21 being a resilient member. The cylinder rubber 21 is inclined based on the central line CL so that a resilient main shaft crosses the central line CL at a point (b) thereon. This constitution automatically changes the direction of the rear wheels 12 through utilization of an external force exerted on the rear wheels 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a front and rear wheel steering device for a motorcycle.

[Conventional technology]

Conventionally, many ideas have been proposed for automobiles in which the front and rear wheels are steered together, and it is known that steering the front and rear wheels in the same phase improves running stability at medium and high speeds. For this reason, it is desired that motorcycles be able to steer the front and rear wheels, and there are examples of methods that meet this demand, such as Japanese Patent Laid-Open No. 61-1
There is one disclosed in Japanese Patent No. 57479. This is a system in which a cantilevered rear arm is swingably supported on the vehicle body frame, and an axle box that supports the rear wheel axle is supported at the rear end of this rear arm so that it can be turned left or right. By connecting to the front fork through members such as wires and links, the rear wheels are configured to turn left and right when the steering handle is operated.

(Problem to be Solved by the Invention) However, in such a structure, the axle box is rotatably supported with respect to the rear arm, and the rear wheel axle supported by the axle box and the drive shaft driven by the chain are connected. Although the axle box and front fork must be connected through a universal joint, the structure becomes extremely complicated because the axle box and front fork must be connected using wires, link members, and other members. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a front and rear wheel steering device for a motorcycle that can perform front and rear wheel steering with a simple structure.

[Means to solve the problem]

The front and rear wheel steering device for a motorcycle according to the present invention includes a rear arm that supports a rear wheel, or an engine and a rear wheel that are integrated into a bracket that is supported on a vehicle body frame via an elastic member that is elastically deformed mainly in the horizontal direction. The main axis of elasticity of the elastic member is inclined with respect to the center line in the longitudinal direction of the vehicle body. here,
The phrase "elastically deforming mainly in the horizontal direction" means that the elastic member deforms elastically so as to move the bracket horizontally.

[Operation] In the present invention, when a motorcycle is turned and a cornering force is applied to the rear wheel, the elastic member is elastically deformed, the rear arm or the unit swing type engine swings horizontally, and the rear wheel is turned. It becomes like this.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view taken along the line I-1 in FIG.
3 is a side view showing the main parts of the front and rear wheel steering system for a motorcycle, and FIG. 4 is a side view showing the entire motorcycle. In these figures, the reference numeral 1 indicates the body frame. shows. This body frame 1 has a head vibe 2,
A tank rail 4 extends rearward from the head vibe 2 and supports the fuel tank 3; a down tube 6 extends downward from the front of the tank rail 4 and supports the front side of the engine 5; It consists of a rear arm bracket 7 connected to the rear end. 8 is a bracket supported by the rear arm bracket 7 via an elastic member which will be described later, and 9 is a rear arm pivotally supported at the rear of the bracket 8 by a pivot bolt 11. This rear arm 9 is constructed by connecting left and right arm portions 9a, 9a with a cylindrical portion 9b at the front end and a reinforcing portion 9c disposed behind the cylindrical portion 9b. 12 is a rear wheel rotatably supported at the rear end of the rear arm 9; 13 is a shock absorber disposed at the center of the vehicle body immediately behind the engine 5 for damping vertical movement of the rear arm 9; A lower end portion of the shock absorber 13 is connected to the rear arm 9 via a link mechanism (not shown), and an upper end portion is pivotally attached to the upper rear side of the rear arm bracket 7.

The rear arm brackets 7 are disposed on both sides of the vehicle body so as to face each other, and the front center portions 7a of the side walls are inclined with respect to the longitudinal center &%CL of the vehicle body so that the facing distance becomes narrower as the front side goes forward. There is. Reference numeral 15 denotes a support wall that protrudes from inside the front center portion 7a so as to face it at a constant interval. Reference numeral 16 denotes a support bolt with a rectangular cross section that is horizontally suspended between the support wall 15 and the front center portion 7a, and a line extending from the center line that is perpendicular to the support wall 15 and the front center portion 7a is on the center line CL. The lines extend to intersect at point b.

A support wall 15 and a front center portion 7 are provided on the front side of the bracket 8.
A cylindrical portion 17.17 is provided facing between a and a. This cylindrical portion 17 extends parallel to the support wall 15, and a line obtained by extending the center line in the radial direction intersects at point a on the center line CL, and serves as an elastic member that mainly deforms elastically in the horizontal direction. Cylindrical rubber 2
1 and supported by a rear arm bracket 7.

The cylindrical rubber 21 is an outer cylinder 22 that is fitted and fixed to the cylinder part 17.
, an inner cylinder 23 fitted onto the support bolt 16, and a cylindrical rubber member 24 baked onto these members. As shown in FIG. 2, the inner cylinder 23 is formed to have an elliptical cross section with a square hole, and is regulated by a support bolt 16 so that the long axis of the ellipse extends in the vertical direction. That is, the thick portion of the rubber member 24 is disposed in the longitudinal direction of the vehicle body, and the thin portion is disposed in the vertical direction of the vehicle body, so that the cylindrical rubber 21 has a large amount of elastic deformation in the direction of horizontally moving the cylindrical portion 17. The amount of elastic deformation is set small in the direction in which the cylindrical portion l7 is moved in the vertical direction.

In addition, the main axis of elasticity of the cylindrical rubber 21 is between center line C and b of E.
It is inclined with respect to the center line CL so as to intersect at a point.

Note that 25 is a seat rail that supports the seat 26, and 27 is a seat rail that supports the seat 26.
is the pack stay that supports the rear part of the seat rail 25, and the 0 point is the center point of the rear wheel I2.

In the front and rear wheel steering device for a motorcycle configured in this way, when the front wheel is turned to the right and the motorcycle starts turning at high speed, the rear wheel 1 is turned as shown in FIG.
The vehicle body center line CL, which indicates the direction of No. 2, and the direction of travel become deviated by a slip angle θ. Therefore, a cornering force F is generated, and the center point g1 of the cylindrical rubber 21. Forces F, , F perpendicular to this cylindrical rubber 21 act on gt. Here, since the point b is located behind the cylindrical rubber 21, the forces F+ and Fz act in a direction to swing the bracket 8 clockwise. Note that displacement of the cylindrical rubber 21 in the axial direction due to the forces L+ and Lz is prevented by the rear arm bracket 7 and the support wall 15. As a result, the rubber member 24 is elastically deformed, and the bracket 8 and rear arm 9 swing clockwise in the figure around point b, so that the rear wheel 12 is oriented in the direction in which the motorcycle is turned. Become. That is, the direction of the rear wheels 12 can be controlled using the cornering force F generated on the rear wheels 12 without using any special device. Therefore,
Since it is possible to prevent the line connecting the center of the front wheel and the center of the rear wheel 12 from being misaligned with the traveling direction at the center of gravity of the motorcycle, running stability can be improved.

FIG. 6 is a sectional view corresponding to FIG. 1 showing the second embodiment, and in this figure, the same or equivalent members as shown in FIG. In this embodiment, the front center portion 7a of the pillar 7 is inclined with respect to the longitudinal center line CL of the vehicle body so that the facing distance becomes narrower toward the rear. Then, a bracket 1 is attached via a cylindrical rubber 21 to a support bolt 16 that is horizontally suspended between support walls 31 and 31 that protrude inward.
A cylindrical portion 17 of 8 is supported. The support bolt 16
The inclination angle is set so that point b, which is the intersection of the extended lines of the center line, and point 0, which is the center of the rear wheel 12, coincide with each other. Therefore, in this embodiment, the rear wheel 12
Since the bracket 8 and the rear arm 9 swing horizontally about point b, which coincides with the center of the rear wheel 12, the direction of the rear wheel 12 can be changed without changing the center position.

7 to 9 show the case where the present invention is applied to a scooter, FIG. 7 is a side view showing the entire scooter, and FIGS. 8 and 9 are side views showing the third and fourth embodiments. 1 is a cross-sectional view corresponding to FIG. In these figures, 41 is a scooter, which has a footboard 44 on which legs are placed between a steering handle 42 and a seat 43, and is equipped with a unit swing type engine 45 at the rear. This unit swing type engine 45 has an engine body 45a, a bearing part 45b that supports the rear wheel 12, and a transmission case 4 that incorporates a transmission device that transmits the output of the engine body 45a to the rear wheel 12.
5e and is integrally supported.

46'' is a main pipe that extends from the front side of the vehicle body under the footboard 44 to the rear of the vehicle body and constitutes the vehicle body frame, and 47 is a stay that projects from the center lower part of this main vibe 46.The stay 47 has a cross-sectional shape of In FIG. 8 showing the third embodiment, support walls 51 and 51 are formed substantially similar to the bracket 7, and in FIG. 9 showing the fourth embodiment, support walls 51 and 51 are provided. 52. 52 is provided to protrude toward the inside of the vehicle body.Furthermore, the bracket 8 is also formed in substantially the same manner as the one that pivotally supports the rear arm, and the cylindrical portion 17 is provided to protrude forward in the third embodiment. In the fourth embodiment, the unit swing type engine 45 has a pivot port 11 that passes through a pair of brackets 53 and 53 that project from the front surface of the engine body 45a.
It is pivotally supported at the rear of the bracket 8.

Therefore, such a unit swing type engine 4
5, when cornering force acts on the rear wheel 12, the cylindrical rubber 21 is elastically deformed,
The rear wheels 12 are oriented in the direction in which the scooter 41 is turned. That is, since the main elastic axes of the left and right cylindrical rubbers 21 intersect at point b rearward of the cylindrical rubbers 21, the rear wheels 12 are operated in the same phase as the steering handle 42.

In addition, in the above embodiment, the cylindrical rubber 21 provides
Although an example has been described in which the bracket 8 is supported movably in the horizontal direction, the present invention is not limited to this. It can also be configured to be regulated by an elastic member such as rubber, a coil spring, or a leaf spring.

(Effects of the Invention) As explained above, according to the present invention, the rear arm supporting the rear wheel or the engine and the rear wheel are attached to the bracket rotatably supported in the horizontal direction on the vehicle body frame via an elastic member. The integrally supported unit swing type engine is pivotally supported, and the elastic main axis of the elastic member is inclined with respect to the center line in the longitudinal direction of the vehicle body, so when the motorcycle is turned and cornering force is applied to the rear wheel, the elastic member Since the rear arm or unit swing type engine can be elastically deformed to swing in the horizontal direction, the rear wheels can be turned.

Therefore, the direction of the rear wheels can be automatically changed using an external force acting on the rear wheels, and there is no need for special means for steering the rear wheels as in the past, resulting in a simple structure. It is possible to perform front and rear wheel steering.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view taken along the line I-1 in FIG.
-n line sectional view, Figure 3 is a side view showing the main parts of the front and rear wheel steering system for a motorcycle, Figure 4 is a side view showing the entire motorcycle, and Figure 5 is a schematic diagram of the main parts to explain the operation. figure,
FIG. 6 is a sectional view corresponding to FIG. 1 showing the second embodiment;
Figure 7 is a side view showing the entire scooter, Figures 8 and 9
The figure is a sectional view corresponding to FIG. 1 showing the third and fourth embodiments. 1...Vehicle frame, 7.11. Rear arm bracket, 8...Bracket, 9...Rear arm,
12... Rear wheel, 21... Cylindrical rubber, 45...
・Unit swing type engine. Figure 2 Figure 3 Patent applicant Yamaha Motor Co., Ltd.

Claims (2)

[Claims] (1) A rear arm that supports the rear wheel is pivoted to a bracket supported on the vehicle body frame via an elastic member that is elastically deformed mainly in the horizontal direction, and the elastic main axis of the elastic member is aligned with the longitudinal centerline of the vehicle body. A front and rear wheel steering device for a motorcycle, which is tilted toward the front. (2) A unit swing type engine that integrally supports the engine and rear wheels is pivotally supported on a bracket supported on the vehicle body frame via an elastic member that elastically deforms mainly in the horizontal direction, and the elastic member A front and rear wheel steering device for a motorcycle, which has an elastic main axis tilted with respect to a center line in the longitudinal direction of the vehicle body.