JP2000159178A - Front wheel suspension for two wheeler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To devise the structure of a link for better appearance around a front fork and increase a degree of freedom in designing a suspension spring. SOLUTION: One end of an arm 17 is extended where it is almost superposed on a front fork 13 in the side view of a body, so that a Z-shaped link can be formed with a front wheel supporting arm 14, a push rod 15 and the arm 17 as shown in a heavy line. Basically, a bottom link type suspension has the Z-shaped link formed with the front wheel supporting arm, the push rod and the arm. The upper part of the push rod can be put close to the front fork and the front fork can be better in appearance around without requiring a complicated structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel suspension system for a motorcycle, and more particularly to an improved technique for a bottom link type suspension.

[0002]

2. Description of the Related Art As a front suspension for a motorcycle, a telescopic suspension or a bottom link suspension is currently the mainstream. The telescopic suspension has a structure that expands and contracts literally like a telescope, and is suitable for those having a relatively small caster angle (the angle between the vertical line and the front fork).

[0003] On the other hand, in a motorcycle having a large caster angle called a so-called American motorcycle, since the front fork is sleeping, it is difficult to absorb the vertical movement of the front wheels with a telescopic suspension. Since the bottom link type suspension is hardly affected by the caster angle, it can be said that the bottom link type suspension is suitable for a motorcycle having a large caster angle.

As a technique relating to a bottom link type suspension, for example, Japanese Utility Model Publication No. 60-15744, "Front Wheel Suspension System for Motorcycles" has been proposed. This suspension system is shown in FIGS. 1 and 2 of the publication. The front wheel W is suspended by parallel links (consists of reference numerals 3, 8, 6, F) and suspension coil springs (14). In addition,
FIG. 1 is a leading type suspension because the axle (5) of the front wheel (W) is in front of the suspension, and FIG. 2 is a trailing type because the axle (5) of the front wheel (W) is behind the suspension. It is called a suspension. FIG. 2 is a simplified version of FIG.

FIG. 15 is a principle diagram of a conventional typical bottom link type suspension. However, the code has been reassigned. One end of a front wheel support arm 102 is swingably attached to the lower end of the front fork 101, and the axle 104 of the front wheel 103 is attached to the tip of the front wheel support arm 102.
05, and another link 106 in which the upper part of the push rod 105 is extended from the upper part of the front fork 101.
By connecting the tip of this link 106 to the suspension spring 107 and the lower end of a hydraulic damper (not shown),
The front wheel 103 is suspended by a parallel link structure, and indicates that the axle 104 moves from or to when the front wheel 103 moves up or down.

[0006]

According to the above-mentioned parallel link structure, the link 106 satisfactorily follows the behavior of the front wheel support arm 102, and the tip of the link 106 is connected to the suspension spring 107.
The axle 104 can be supported by holding the axle. On the other hand, since the raising operation of the axle 104 and the compression operation of the suspension spring 107 simply correspond to each other, the characteristics of the suspension spring 107 must be simply adapted to the behavior of the axle 104, and the design of the suspension spring 107 is free. The degree becomes poor.

Further, because of the parallel link structure, the push rod 105 must be arranged substantially parallel to the front fork 101 and as far as possible. As a result, when the vehicle body is viewed from the side, the push rod 105
Is noticeable and does not look good. Therefore, it is unavoidable that the overhang 108 (FIG. 1)
5), the push rod 105 must be brought closer to the front fork 101 as much as possible. As a result, as shown in FIG. 2 of the above publication, the front fork must have a triangular and complicated structure. SUMMARY OF THE INVENTION It is an object of the present invention to improve the appearance of the front fork without increasing the complexity of the structure around the front fork by expanding the link structure, and to expand the degree of freedom in designing the suspension spring.

[0008]

In order to achieve the above object, a front wheel supporting arm is attached to a front fork so as to be swingable, and an axle of a front wheel is mounted at a tip of the front wheel supporting arm. A push rod is set up from the middle, the upper end of the push rod is connected to one end of or near the upper link arranged near the bottom bridge, the other end of the upper link is swingably attached to the bottom bridge, and the upper link is connected to the suspension spring. By connecting one end of the upper link to a position almost overlapping with the front fork when the vehicle body is viewed from the side,
Z with front wheel support arm, push rod and upper link
Character links are configured.

Basically, the suspension is a bottom link type suspension, but the upper part of the push rod is brought close to the front fork by forming a Z-link with the front wheel support arm, the push rod and the upper link. As a result, the appearance of the front fork is improved without having a complicated structure. Furthermore, since it is a Z-shaped link, the length of the constituent members,
The mounting posture and the relative angle can be freely selected, and the degree of freedom in designing the suspension spring can be increased.

According to a second aspect of the present invention, a pivot shaft for fixing the front wheel support arm to the front fork is offset from the center of the front fork toward the rear wheel. By moving the pivot shaft of the front fork toward the rear wheel, the lower part of the push rod is separated from the front fork, and a space for storing components constituting the suspension device is secured.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that "before", "after",
“Left”, “right”, “up”, and “down” follow directions seen from the driver. Also, the drawings should be viewed in the direction of reference numerals. FIG. 1 is a side view of the front half of a motorcycle according to the present invention.
The motorcycle 1 has a vertically-oriented steering stem 4 attached to a head pipe 3 of a body frame 2 so as to be rotatable left and right.
A top bridge 11, which will be described later, is mounted on an upper portion of the steering stem 4, a bar handle 5 is mounted on the top bridge 11, and a bottom link type front wheel suspension device 10 is mounted on the steering stem 4.
The front brake 50 of the motorcycle 1 includes a brake disc 51 mounted on a side of the front wheel 32 and a caliper 56 for controlling the braking of the brake disc 51.
It is a hydraulic disc brake. 61 is a headlamp.

FIG. 2 is a side view of the front wheel suspension device according to the present invention. The front wheel suspension device 10 includes a top bridge 11 attached to an upper portion of the steering stem 4, a bottom bridge 12 attached to a lower portion of the steering stem 4, and a front fork 13 having an upper end attached to the top / bottom bridges 11, 12. A front wheel support arm 14 having a front end connected to the lower end of a front fork 13 extending forward and downward so as to be able to swing up and down; Push rod 15 and push rod 1 extending upward
In order to connect the upper end of 5 through a rod hanger 16,
An upper link 17 extending from the bottom bridge 12 to be able to swing upward and downward, a shock absorber 18 having a lower end connected to the upper link 17, and a front fork 13 for connecting an upper end of the shock absorber 18 extending upward. This is a trailing arm type suspension device including an upper bracket 19 attached to an upper portion. In the figure, reference numerals 21 to 25 are connection pins.

Since the trailing arm system is used, a front wheel axle 31 is mounted on the rear end of the front wheel support arm 14, and a front wheel 32 is rotatably mounted on the axle 31. The front wheel support arm 14 employs a bolting method called "split tightening" to attach the axle 31 without loosening. Split fastening means a split groove (slit) 14a extending to the front wheel support arm 14 to a hole into which the axle 31 is fitted.
Is formed, and the portion of the split groove 14a is tightened with the bolt 27. This figure shows that the left front wheel support arm 14 is attached by split tightening, but the same applies to the right front wheel support arm (not shown).

The front wheel suspension device 10 includes (1) a front fork 1 in front of a steering stem 4 in a side view.
3 with placing, that has been set loosely inclination angle of the front fork 13 than the inclination angle of the steering stem 4, and (2) in side view, the center of the center O ₁ on the shock absorber 18 of the front fork 13 O ₂ Are substantially matched. The shock absorber 18 includes a hydraulic damper 41 and a damper 4.
1 is a spring-covered shock absorber comprising a suspension spring 42 wound around the periphery of the shock absorber. As is apparent from FIG.
The outer diameter of the suspension spring 42, which is the maximum diameter of 8, is substantially equal to the diameter of the front fork 13.

The axle 31 has a bracket 52 orthogonal to the axle 31 mounted so as to swing up and down.
The bracket 52 includes a first bracket 53 attached to the axle 31 and a second bracket 54 attached to the tip of the first bracket 53. The second bracket 54 is a member that connects the distal end side of the second bracket 54 to an intermediate portion in the longitudinal direction of the front fork 13 via a torque transmission link 55 and attaches the caliper 56 and the front fender 62. The two ends of the torque transmitting link 55 are connected to the connecting pins 5.
A link member, such as a bracket 52, for preventing rotation of the bracket 52, which is connected so as to be able to swing up and down at 7, 58.

FIG. 3 is an exploded side view of the front wheel suspension device according to the present invention, and shows the connection relationship of each member in the front wheel suspension device 10. In this figure, particularly, a connecting portion 12a is provided at a lower end of the bottom bridge 12, and a rear end connecting portion 17a of the upper link 17 (also referred to as "crank") is provided at the connecting portion 12a.
Are connected so as to be able to swing up and down, and the lower end portion 18a of the shock absorber 18 is connected so as to be able to swing up and down to a front end connecting portion 17b of the upper link 17, and an intermediate connecting portion 17c of the upper link 17 is connected.
Shows that the upper connecting portion 16b of the rod hanger 16 is connected so as to be able to swing up and down. The intermediate connecting portion 17c is provided midway in the longitudinal direction of the upper link 17 and higher than the front end connecting portion 17b. This figure also shows that the split groove 14a of the front wheel support arm 14 is cut out to a fitting hole 14b for fitting a front wheel axle.

FIG. 4 is a perspective view of the front wheel suspension device according to the present invention, and shows a pipe (front fork pipe) 13 of a front fork 13 which is a component of the front wheel suspension device 10.
a, the left and right front wheel support arms 14, push rods 15, and shock absorbers 18 are shown. The top / bottom bridges 11 and 12 have a substantially U-shape in plan view so as not to interfere with the left and right shock absorbers 18 and 18. In addition, the first and second brackets 53 and 54 and the torque transmission link 5
5 is also provided one each for left and right. Left and right torque transmission links 5
5 and 55 are slightly curved toward the center of the vehicle body so as not to interfere with the push rods 15 and 15. Note that the torque transmission links 55, 55 are
If it does not interfere with 5, it may be a straight structure.

FIG. 5 is a front view in cross section of a main part of the front wheel suspension device according to the present invention, and shows the front wheel suspension device 10 which is symmetrical with respect to the center CL of the vehicle body. Rod hanger 1
6 are left and right rod mounting portions 16a, 16a into which the upper ends of the push rods 15, 15 are screwed, and the upper link 1
7 is a substantially inverted Y-shaped member as viewed from the front, in which a central upper connecting portion 16b connected to the front end 7 is integrally formed. Upper link 17
Is a single member connecting the lower end portions 18a, 18a of the left and right shock absorbers 18, 18. The upper bracket 19
It is a member bridged between the left and right front fork pipes 13a, 13a below the top bridge 11. An upper cushion member 43 such as rubber is attached to the upper bracket 19.
By suspending the damper rods 45, 45, which are the upper end portions of the shock absorbers 18, 18, via the lower cushion members 44, 43 so as to be able to swing in all directions in plan view, the shock absorbers 18, 18 are suspended from the top bridge 11. Can be connected to the side. That is, the shock absorbers 18, 18 are not directly connected to the top bridge 11, but are connected to the top bridge 11 via the upper bracket 19. The shock absorbers 18 may be directly connected to the top bridge 11.

FIG. 6 is a plan sectional view of the front wheel support arm according to the present invention, which is developed on the basis of each connecting portion. This figure shows the front forks 13
The front end portions (one end portions) of the front wheels 4 and 14 are connected by connecting pins 21 and 21, and the push rods 15 and 15 are connected to the intermediate portions of the front wheel supporting arms 14 and 14 by the connecting pins 22 and 22. Axle 3 between the rear end (other end) of
1 indicates that the first brackets 53, 53 have been attached to the axle 31.

Next, the operation of the front wheel suspension device 10 having the above configuration will be described with reference to FIGS. FIG. 7 is an operation diagram (part 1) of the front wheel suspension device according to the present invention, and shows a state of the front wheel suspension device 10 when a downward load is not acting on the front wheel 32. The front wheel 32 is at the lower limit level, and the upper link 17 at this time is at the lower limit position D shown in the figure. As a result, the shock absorber 18 is in the most extended state. Shock absorber 18
Is substantially the same as the front surface of the front fork 13.

FIG. 8 is an operation diagram (part 2) of the front wheel suspension device according to the present invention, in which the state of the front wheel suspension device 10 when the front wheel 32 is at the intermediate level, that is, the shock absorber 18 is in the state shown in FIG.
It shows that it contracted to some extent from the state of. When a downward light load about the weight of the motorcycle 1 acts on the body frame 2, the light load is applied to the head pipe 3 → the steering stem 4 → the top / bottom bridge 11, 12 → the front fork 13 → the front wheel support arm 14 → the axle 31. → front wheel 32
On the road surface F. The reaction force from the road surface F to the shock absorber 1 in the route of the front wheel 32 → the axle 31 → the push rod 15 → the rod hanger 16 → the upper link 17
It is transmitted to 8. As a result, the front wheel support arm 14 is
Swing slightly upward from the state of
As the rod hanger 16 rises, the front end of the upper link 17 swings upward.
8 contracts by a stroke corresponding to a light load. The front side surface of the shock absorber 18 at this time is substantially the same as the front side surface of the front fork 13.

FIG. 9 is an operation diagram (part 3) of the front wheel suspension device according to the present invention, and shows a state of the front wheel suspension device 10 when the front wheel 32 is at the upper limit level, that is, a state where the shock absorber 18 is most contracted. Show. When a heavy downward load is applied to the body frame 2, the heavy load is transmitted to the road surface F along the same route as the route shown in FIG. A reaction force from the road surface F is transmitted from the front wheel 32 to the shock absorber 18. As a result, the rear portion of the front wheel support arm 14 further swings upward, and the push rod 15 and the rod hanger 16 move upward, so that the front end of the upper link 17 swings upward to the upper limit position U. It contracts by the stroke corresponding to the load. The front side surface of the shock absorber 18 at this time is substantially the same as the front side surface of the front fork 13.

As is apparent from the above description, the front wheel suspension device 10 extends the upper link 17 forward and downward from the bottom bridge 12 in a side view so as to swing upward and downward, and connects the lower end of the shock absorber 18 to the upper link 17. The upper end of the shock absorber 18 is connected to the upper bracket 19 on the top bridge 12 side. In FIG. 9, the upper link 17 swings up and down by a swing angle θ in a range between a lower limit position D indicated by an imaginary line and an upper limit position U indicated by a solid line. When the upper link 17 swings, the shock absorber 18 swings back and forth with reference to the upper bracket 19.

The center of the shock absorber 18 is set so as to substantially coincide with the center of the front fork 13. In addition, the suspension spring 4 which is the maximum diameter of the shock absorber 18
The outer diameter of 2 is set substantially equal to the diameter of the front fork 13. Further, in a state where the shock absorber 18 is most contracted, the upper link 17 is at an upper limit position U in a direction substantially orthogonal to the front fork 13 in a side view. Accordingly, in the range of the swing angle θ of the upper link 17, that is, in the range of ascending and descending of the front wheel 32, the shock absorber 1
8 does not protrude forward of the front fork 13.

FIG. 10 is an explanatory view showing that the link structure of the present invention is a Z-shaped link. A front wheel support arm 14 is attached to a front fork 13 so as to be able to swing. The axle 31 of the front wheel 32 is attached, the push rod 15 is set up from the middle of the front wheel support arm 14, and the upper end of the push rod 15 is connected to one end of the upper link 17 or its vicinity, and the other end (right end) of the upper link 17 Is swingably attached to the bottom bridge 12, the upper link 17 is connected to the lower end of the suspension spring 42, and the upper link 17 is provided when the vehicle body is viewed from the side.
Is extended to a position substantially overlapping with the front fork 13, thereby forming a Z-shaped link with the front wheel support arm 14, the push rod 15, and the upper link 17 as shown by a thick line.

As is apparent from the figure, the Z-shaped link indicated by the bold line is a non-parallel link having different angles α and β, and these angles α and β can be freely set as necessary.
Dimensions (length) of front wheel support arm 14 and upper link 17
Can be freely set, so that the degree of freedom in designing the suspension spring 42 can be increased. Also, since the upper part of the push rod 15 can cross the front fork 13, the push rod 1
5 can be brought close to the front fork 1
The appearance can be improved without making the three turns a complicated structure, and the moment of inertia around the front fork 13 can be reduced to enhance the steering performance.

Next, a pivot shaft 21 for fixing the front wheel support arm 14 to the front fork 13 is offset from the center of the front fork 13 by δ toward the rear wheel. As a result, the space S between the front fork 13 and the lower part of the push rod 15 can be appropriately secured, and suspension components such as the torque transmission link 55 can be easily arranged.

Next, the shape and operation of the front wheel support arm 14 will be described with reference to FIGS. FIG. 11 is a schematic view of a front wheel suspension device provided with a downwardly convex front wheel support arm, which is a drawing based on FIG. 10, wherein the front wheel support arm 14 is a downwardly convex V-shaped arm. In the figure, a sufficiently large space S exists between the front fork 13 and the push rod 15. When the front wheel 32 relatively rises from this state, the connecting pin 22 moves to a point A along an arc centered on the pivot shaft 21. As a result, the space S increases. Therefore, there is no difficulty in arranging components in the space S.

FIG. 12 is a schematic view of a front wheel suspension device having a rod-shaped front wheel support arm.
Is a simple rod-shaped arm in which the pivot shaft 21, the connecting pin 22 and the axle 31 are substantially aligned. In the figure, there is a space S1 between the front fork 13 and the push rod 15, and when the front wheel 32 relatively rises from this state, the connecting pin 22 moves to the point B along an arc centered on the pivot shaft 21. Move up to. As a result, the space S1 becomes narrow. Therefore, care must be taken when arranging components in this space S1.

FIG. 13 is a schematic view of a front wheel suspension device having an upwardly convex front wheel support arm.
Is an upwardly convex V-shaped arm. In the drawing, a space S2 exists between the front fork 13 and the push rod 15, and when the front wheel 32 relatively rises from this state, the connecting pin 22 moves to a point C along an arc centered on the pivot shaft 21. Move up to. As a result, the space S2 becomes extremely narrow. Therefore, extra care must be taken to place components in this space S2.

Considering the above-mentioned FIGS. 11 to 13, the point that a sufficiently large space can be secured is lower than that of the front arm support arm 14C (FIG. 13), which is a convex arm-shaped upper arm. A convex V-shaped front wheel support arm 14 (FIG. 1)
1) is more preferable, and it can be seen that the rod-shaped front wheel support arm 14B (FIG. 12) is intermediate between the two.

FIG. 14 is a view showing a modified embodiment of FIG. 2. In this front wheel suspension device 10, the push rod 15 is a non-straight, specifically, a curved push rod having a V shape. I do. The other configuration is the same as that of FIG. 2, and the detailed description is omitted by using the reference numerals. Despite the adoption of the curved push rod, a line connecting the pivot shaft 21, the connecting pin 22 at the lower end of the push lot 15, the connecting pin 25 at the upper end of the push rod 15, and the connecting pin 23 at the base of the upper link 17 (thick line) ) Form a Z-shaped link as shown in the figure.

Therefore, in the first aspect, “the Z-link is formed by the front wheel support arm, the push rod and the upper link” means that the pivot shaft 21, the connecting pin 22 at the lower end of the push rod 15, and the upper end of the push rod 15. Connecting pin 2
5 and the connection pin 23 at the base of the upper link 17 to form a Z-link.

In this embodiment, the trailing suspension is described as an example, but the Z-link structure of the present invention and the offsetting by δ may be applied to the leading suspension. Further, the front wheel suspension device of the present invention is suitable for a motorcycle, but can also be adopted for a motorcycle (bicycle) without an engine.

[0035]

According to the present invention, the following effects are exhibited by the above configuration. The front wheel suspension device according to claim 1 is basically a bottom link type suspension. However, by forming a Z-shaped link between the front wheel support arm, the push rod, and the arm, the upper part of the push rod can be brought close to the front fork. The appearance can be improved without having a complicated structure around the front fork. Further, since the link is a Z-shaped link, the length, the mounting posture, and the relative angle of the constituent members can be freely selected, and the degree of freedom in designing the suspension spring can be increased.

According to a second aspect of the present invention, the pivot shaft for fixing the front wheel support arm to the front fork is offset from the center of the front fork toward the rear wheel, and the pivot shaft of the front fork is moved toward the rear wheel. ,
The lower part of the push rod is separated from the front fork, so that a space for storing components constituting the suspension device can be secured.

[Brief description of the drawings]

FIG. 1 is a side view of a front half of a motorcycle according to the present invention.

FIG. 2 is a side view of the front wheel suspension device according to the present invention.

FIG. 3 is an exploded side view of the front wheel suspension device according to the present invention.

FIG. 4 is a perspective view of a front wheel suspension device according to the present invention.

FIG. 5 is a cross-sectional front view of a main part of the front wheel suspension device according to the present invention.

FIG. 6 is a plan sectional view of a front wheel support arm according to the present invention.

FIG. 7 is an operation diagram (part 1) of the front wheel suspension device according to the present invention.

FIG. 8 is an operation diagram (part 2) of the front wheel suspension device according to the present invention.

FIG. 9 is an operation diagram (part 3) of the front wheel suspension device according to the present invention.

FIG. 10 is an explanatory view showing that the link structure of the present invention is a Z-shaped link.

FIG. 11 is a schematic diagram of a front wheel suspension with a downwardly convex front wheel support arm.

FIG. 12 is a schematic view of a front wheel suspension device having a rod-shaped front wheel support arm.

FIG. 13 is a schematic diagram of a front wheel suspension with an upwardly convex front wheel support arm.

FIG. 14 is a diagram showing a modified embodiment of FIG. 2;

FIG. 15 is a principle diagram of a conventional typical bottom link type suspension.

[Explanation of symbols]

1 ... motorcycle (motorcycle), 2 ... body frame, 10 ...
Front wheel suspension device, 13: Front fork, 14: Front wheel support arm, 15: Push rod, 17: Upper link, 21: Pivot shaft, 31: Axle (front wheel axle), 3
2: Front wheel, 42: Suspension spring, δ: Offset amount.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shinji Ito 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3D014 DE06 DE13 DE14 DE34 DE36

Claims (2)

[Claims] 1. A front wheel support arm is swingably mounted on a front fork, an axle of a front wheel is mounted on a front end of the front wheel support arm, a push rod is set up in the middle of the front wheel support arm, and an upper end of the push rod is near a bottom bridge. The other end of the upper link is swingably attached to the bottom bridge, the upper link is connected to the lower end of a suspension spring, and when the vehicle body is viewed from a side, the upper A front wheel suspension system for a two-wheeled vehicle, wherein one end of a link is extended to a position substantially overlapping with a front fork, thereby forming a Z-shaped link with a front wheel support arm, a push rod, and an upper link. 2. The two-wheeled vehicle front wheel suspension device according to claim 1, wherein a pivot shaft for fixing the front wheel support arm to the front fork is offset from the center of the front fork toward the rear wheel.