JPH022751B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a front wheel suspension system for a motorcycle.

(Prior technology) Front wheel suspension systems for motorcycles are generally divided into two types: a telescopic system with sliding inner and outer cylinders, and a link system. Each structure has its own features, but the current trajectory is The telescopic method, which is linear and has a sufficient stroke, has become mainstream.

In addition, some car models adopt a link system with good operability, such as a leading type, but this is limited to certain car models because the trajectory of the axle is arcuate and the stroke is not sufficient. That is the reality.

British Patent No. 526,116 discloses a parallelogram link type aircraft wheel suspension having two swing arms.

(Problems to be Solved by the Invention) By the way, when a quadrilateral link type suspension system is applied particularly to the front wheel of a motorcycle, it is necessary to improve the weight balance of the vehicle body and to reduce the moment of inertia relative to the steering stem axis. becomes.

Therefore, an object of the present invention is to create a quadrilateral link system that has good operability in order to transmit force in the rotational direction in accordance with the mechanistic Skotstratzsell theorem, but also has excellent weight balance and steering stability. An object of the present invention is to provide a front wheel suspension system for a motorcycle that can reduce the moment of inertia relative to a stem shaft.

(Means for Solving the Problems) In order to solve the above problems and achieve the objects, the present invention provides a front wheel suspension system for a motorcycle, in which an upper fork 3 is rotatably supported at the upper part of a head pipe 11. and a lower fork 6 with a wheel 8 pivotally supported on the front part thereof are connected by front and rear swinging arms 4, 5 to form a quadrilateral link in side view, and an elastic means 7 is provided that acts on the quadrilateral link, The swing arms 4 and 5 and the lower fork 6 are arranged on the rear side of the upper fork 3, and the rotation axis S of the upper fork 3 with respect to the head pipe 11 is arranged so as to intersect with the quadrilateral link in side view. It is characterized by what it did.

(Function) In particular, since the swing arms 4 and 5 and the lower fork 6 are arranged on the rear side of the upper fork 3, the quadrilateral link can be arranged close to the frame 1, and therefore the weight balance of the vehicle body is improved. Furthermore, since the rotation axis S of the upper fork 3 is arranged to intersect with this quadrilateral link in a side view, the moment of inertia of the quadrilateral link with respect to the steering stem axis is reduced.

(Example) Examples will be described below based on the accompanying drawings.

Fig. 1 is a side view of the motorcycle, Fig. 2 is a perspective view showing the link structure of the front wheel suspension system, and a head pipe 11 tilting backward is mounted on the front part of the frame 1 of the motorcycle.
A handle stem shaft (not shown) is rotatably inserted and supported in the head pipe 11, and a top bridge 35 and a bottom bridge are fixed in the middle at the upper and lower ends of the handle stem shaft. A bar handle 2 is fixedly installed.

A pair of left and right upper arms 31, 31 are fixed at the upper portions of both ends of the top bridge 35 and the bottom bridge 36, so that the upper fork 3
is configured. Front and rear swinging arms 4 and 5 are respectively pivoted at pivot points 41 and 51 at the lower ends and intermediate parts of the left and right upper arms 31 forming this upper fork 3, and the lower ends of these swinging arms 4 and 5 are pivoted at pivot points 41 and 51, respectively. A lower arm 61 is pivotally supported at the intermediate portion and rear end at pivot points 42 and 52, respectively. An axle 65 is installed between the front ends of the left and right lower arms 61, and a connecting shaft 66 is installed between the rear ends, thereby forming the lower fork 6.

At the lower part of the front swing arm 4 and the middle part of the upper arm 31, there is a shock absorber 7 serving as a springing means.
That is, a spring 71 and a shock absorber 72 are mounted coaxially, and a wheel 8 serving as a front wheel is mounted on the intermediate portion of the axle 65.

Thus, the front wheel suspension system is lower fork 3,
The front and rear swing arms 4, 5 and the lower fork 6 form a quadrilateral link in side view.

In the above, as shown in FIG. 3, the front and rear swing arms 4 and 5 are arranged so as to converge downward, that is, each pivot point 4 of the front swing arm 4 with respect to the upper arm 31 and the lower arm 61
1 and 42 and the line segment l ₂ that also connects the respective pivot points 51 and ₅₂ of the swinging arm 5 on the rear side intersect below, so that the line segment l ₁ and the line segment l The intersection point 0 with ₂ is located below the rear half 63 of the lower arm 61.

Here, the front swinging arm 4 is formed shorter than the rear swinging arm 5, and therefore the quadrilateral link has a substantially rhombic shape that is long in the vertical direction, and the shock absorber 7 is disposed in the longitudinal direction within this rhombic link. be done.

Then, above the line segment _{l 3} connecting the axle 65 support point of the lower arm 61 and the pivot point 42 and the line segment l ₁
The bisector _l4 of the angle formed by
In addition, the axle 65 is placed within the angular range formed by the upper part of the line segment _l5 connecting the processes 42 and 52 and the lower part of the line segment _l1 .

In addition, when no load is applied to the vehicle body, the line segment l ₃ is arranged almost horizontally, that is, the front half 62 in front of the intermediate pivot point 42 of the lower arm 61 is arranged almost horizontally, and the initial setting is made. On the other hand,
The line segment l ₂ , that is, the rear half 6 of the lower arm 61
3 is formed by tilting upward at the rear.

Further, both swing arms 4 and 5 and the lower arm 61 are arranged on the rear side of the lower arm 31, and the axis S of the steering stem shaft supported in the head pipe 11 is arranged so as to intersect with the quadrilateral link when viewed from the side. The arrangement is such that the axis S intersects the front and rear swing arms 4 and 5.

Further, the rear swing arm 5 is arranged substantially vertically.

According to the embodiment, since the front and rear swinging arms 4 and 5 constituting the quadrilateral link in side view are arranged so as to converge downward, the instantaneous movement of the front wheel suspension system during the vertical stroke of the axle 65 as shown in FIG. center 0
This allows a sufficient stroke of the axle 65 to be obtained, and the axle 6 can be adjusted based on the length of the swinging arms 4, 5, the angle of convergence, etc.
5 can be set arbitrarily.

Moreover, as in the embodiment, the bisector _l4 of the angle formed by the lower part of the line segment _l1 and the upper part of the line segment _l3 is arranged to be substantially perpendicular to the travel path L of the axle shaft 65, and the line If the axle 65 is placed within the angular range formed by the lower part _l1 and the upper part _l5 , a linear travel path L of the axle 65 can be obtained as shown in FIG.

Also, as in the embodiment, the line segment l ₃ , that is, the lower arm 6
If the front half 62 of 1 is arranged almost horizontally in the initial setting state, the vehicle height can be reduced and the arrangement structure is _excellent in absorbing uneven road surfaces _. That is, forming the rear half 63 of the lower arm 61 by bending it upward is advantageous in terms of preventing the lower arm rear half 63 from being hit by the ground.

In particular, since both the swing arms 4 and 5 and the lower fork 6 are arranged on the rear side with respect to the lower fork 3, the quadrilateral link can be arranged closer to the frame 1, thereby improving the weight balance of the vehicle body.

Furthermore, since the quadrilateral link is arranged so that the axis S of the steering shaft intersects with the front and rear swing arms 4 and 5 when viewed from the side, the moment of inertia of the quadrilateral link with respect to the steering shaft is reduced. can do.

(Effects of the Invention) As described above, according to the front wheel suspension system for a motorcycle of the present invention, although it uses a quadrilateral link system with good operability, it has excellent weight balance and can reduce the moment of inertia with respect to the steering stem axis. can.

[Brief explanation of drawings]

FIG. 1 is a side view of the motorcycle, FIG. 2 is a perspective view showing the link structure of the front wheel suspension, and FIG. 3 is a schematic side view showing the arrangement and operation thereof. In the drawings, 1 is a frame, 11 is a head pipe, 3 is an upper fork, 31 is an upper arm, 35, 36 are bridges, 4, 5 are swing arms, 41, 42, 51, 52 are pivot points, 6 is the lower fork, 61 is the lower arm, 65 is the axle,
66 is a connecting shaft, 7 is a shock absorber, 8 is a wheel, _l1 ... _l5 are line segments, 0 is a momentary center, L is a stroke path of the axle, and S is an axis of the handle stem shaft.

Claims (1)

[Claims] 1. An upper fork rotatably supported at the upper part of the head pipe and a lower fork with a wheel pivotally supported at the front are connected by front and rear swinging arms to form a quadrilateral link in side view. A springing means acting on the quadrilateral link is provided, a swing arm and a lower fork are disposed on the rear side of the upper fork, and the rotational axis of the upper fork with respect to the head pipe is set to A front wheel suspension system for a motorcycle, characterized in that the front wheel suspension system is arranged so as to intersect with a shaped link.