JPH05105173A - Front wheel suspension device for motorcycle - Google Patents

Abstract

PURPOSE:To advantageously secure the rigidity of a front swing arm which can arrange an engine at the front and with which a vehicle can be made compact by shortening the between-shaft distance and a cushion unit can be connected. CONSTITUTION:A front swing arm 39 is pivotally supported in vertically swingable manner from the vicinity under an engine of a car body frame, and a steering knuckle 19 is supported by the front edge part of the arm 39. As for the arm 39, the left and right pivot arm parts 40 and 41 which are pivotally supported by a car body frame 6a are connected by a cross member part 42 extending in the car width direction, and the steering knuckle 19 is supported by an edge part 40c which is formed by extending one pivot arm part 40 forwardly. A cushion unit 45 is arranged in the car width direction in front of the pivotal supporting points 40a and 41a of the left and right pivot arm parts 40 and 41 and under the cross member part 42, and both the edges of the unit 45 are connected with a boss part 39a formed in the vicinity of the connection point between the left and right pivot arm parts 40 and 41 and the cross member part 42 through a link.

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, when a steering knuckle is supported by a front swing arm pivotally supported by a vehicle body in a vertically swingable manner. The present invention relates to the improvement of the arrangement structure of the cushion unit, which is advantageous in securing the rigidity corresponding to the bending moment acting on the front swing arm.

[0002]

2. Description of the Related Art In the case of a front wheel suspension system in which a front swing arm is swingably supported by a lower arm disposed below an engine of a vehicle body frame, and a steering knuckle is suspended and supported by the front swing arm, a cushion is used. Various problems occur depending on the arrangement position of the unit, the arrangement direction, and the like. For example, when the cushion unit is vertically arranged above the front swing arm, it becomes difficult to secure a space for arranging the exhaust pipe, the radiator and the like. This problem can be solved by disposing the cushion unit in the vehicle width direction as described in, for example, US Pat. No. 4,526,249.

[0003]

However, in the case of the above-mentioned U.S. Patent, since the cushion unit is arranged rearward of the vehicle body side pivot portion of the front swing arm, the engine arrangement position is pushed rearward, and as a result, the shaft is displaced. As the distance between the vehicles increases, the problem of increased vehicle weight arises.

The present invention has been made in view of the above-mentioned problems of the prior art. Compared with the conventional example described in the above publication, the engine can be arranged at the front side, the axial distance can be shortened, and the vehicle can be made compact. Another object of the present invention is to provide a front wheel suspension device for a motorcycle, which is advantageous in securing the rigidity of the front swing arm to which the cushion unit is connected.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a motorcycle in which a front swing arm is swingably pivoted up and down near a lower portion of an engine of a vehicle body frame, and a steering knuckle is supported at a front end portion of the front swing arm. In the front wheel suspension device, the front swing arm is pivotally supported by the body frame on the left,
The right pivot arm portions are connected to each other by a cross member portion extending in the vehicle width direction, the one pivot arm portion is extended forward, and the extension end portion supports the steering knuckle, and the left, A cushion unit is disposed forward of the pivot of the right pivot arm portion and below the cross member portion in the vehicle width direction, and both ends of the cushion unit are linked to the left and right pivot arm portions through links. It is characterized in that it is connected near the connection point between the cross member and the cross member.

[0006]

According to the front wheel suspension system of the present invention, since the cushion unit is arranged in front of the pivot point of the pivot arm portion of the front swing arm and below the cross member portion, the engine arrangement is caused by the cushion unit. The position of the engine can be arranged in front of the conventional one without any trouble in the position, and the distance between the shafts can be shortened to make the entire vehicle compact.

Here, when the cushion unit is connected to the front swing arm, the repulsive force from the unit acts on the front swing arm. Therefore, it is necessary to make the front swing arm rigid enough to cope with the repulsive force. .. According to the present invention, the cushion unit is arranged near the lower part of the cross member part that connects the pivot arm parts of the front swing arm and is connected near the connection point between the pivot arm part and the cross member part, that is, the front swing arm. Since it is connected to the highly rigid portion of the arm, it is advantageous in dealing with the repulsive force.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 are views for explaining a front wheel suspension system for a motorcycle according to an embodiment of the present invention. FIGS. 1 and 2 are plan and side views thereof, and FIGS. III-III
Line, VV line sectional view, FIGS. 4 and 6 are IV-IV line and VI-VI of FIG.
FIG. 7 is a left side view of a motorcycle equipped with the device of this embodiment.

In each of the above figures, 1 is a motorcycle, and 2 is a so-called diamond type vehicle body frame in which the engine unit 8 is a part of the frame. The vehicle body frame 2 has a pair of left and right upper frames 4 and 4 extending obliquely downward and rearward from a head pipe 3 connected to the upper left and right upper ends of a rear arm bracket 5, and the lower end left of the bracket 5.
The rear ends of a pair of left and right lower frames 6 extending substantially horizontally to the right are connected, and the lower frame 6 and the rear arm bracket 5 suspend and support the engine unit 8 and the engine unit 8 The cylinder body 8a and the head pipe 3 are connected by a pair of left and right down tubes 7, 7.

A fuel tank, an air cleaner and the like are mounted above the engine unit 8 and are covered with a tank cover 9. A radiator 10 is arranged in front of the engine unit 8 and is attached to the Danube tube 7. 1
Reference numeral 1 denotes a seat arranged behind the tank cover 9. The rear arm bracket 5 pivotally supports a pivot portion 12a at the front end of the rear swing arm 12 so as to be vertically swingable, and the rear wheel 13 is pivotally supported at the rear end portion of the rear swing arm 12.

A front wheel steering device 14 is supported by the head pipe 3. The front wheel steering device 14 supports a steering knuckle 16 that pivotally supports a front wheel 15, and supports the steering knuckle 16 so as to be slidable in an axial direction and rotatable about an axis, and a steering force from a steering handle 17. And a steering mechanism 18 for transmitting.

The steering knuckle 16 is composed of a knuckle portion 19 which pivotally supports the front wheel 15 at its lower end, and a steering shaft 20 fixed to the upper end of the knuckle portion 19. The knuckle portion 19 has a curved shape extending from the center of the upper edge of the front wheel 15 in the width direction to the axle through the side thereof, and a bearing case 21 is fixed to the lower end thereof. In addition, the steering shaft 2
0 is formed by forming two ball grooves 20a on the left and right sides of the round bar, and is set to a length such that the upper end is located near the lower end of the head pipe 3 in a normal state.

The steering mechanism 18 includes a lower steering cylinder 22 mounted on the steering shaft 20 so as to be axially movable and non-rotatable.
An upper steering tube 23 that is axially immovably and rotatably inserted in the head pipe 3, and the upper and lower steering tubes 2
It is composed of a universal joint 24 that rotatably connects the vehicles 2 and 23 around the vehicle front-rear axis a and the vehicle left-right axis b.

The lower steering tube 22 has a large number of steel balls 25.
Each set of steel balls 25 has a built-in set.
Is fitted in the ball groove 20a. This constitutes a ball spline mechanism that supports the steering shaft 20 so as to move axially and non-rotatably.

A pair of front and rear connecting arm portions 22a are integrally formed on the upper edge of the lower steering cylinder 22 so as to project upward, and the arm ring 22a has the joint ring 26 of the vehicle front-rear shaft. Front and rear shafts 26a are rotatably inserted on a. The left and right shafts 26b located on the left and right shafts b of the joint ring 26 are rotatably inserted into a connecting arm portion 23b integrally formed with the under bracket 23a, and the under bracket 23a is operated by the upper operation. It is fixed to the lower end of the direction cylinder 23. In this way, the universal joint 24 is constructed. 27, 2
Reference numeral 8 denotes a dust boot surrounding the universal joint 24 portion and the steering shaft 20 portion.

A handle holder 29 is provided on the upper end of the upper steering tube 23 projecting upward from the head pipe 3.
Is stuck. A slide shaft 30 having the steering handle 17 fixed to the upper end thereof is inserted in the handle holder 29 so as to be vertically slidable, and the slide shaft 30 can be fixed at a predetermined height position. .. 3
Reference numeral 1 is a cap that closes the upper end opening of the upper steering tube 23.

A pair of left and right tapered bearings 31, 3 are provided in a bearing case 21 fixed to the lower end of the steering knuckle 16.
2 is provided, and the front wheel 1 is provided by the bearings 31 and 32.
Five axles 33 are pivotally supported. A disk-shaped boss 33a formed at one end of the axle 33 has a disc 3 on the outer periphery.
A holder 35 having 4 is bolted and fixed, and a wheel 36 of the front wheel 15 is bolted and fixed to the boss portion 33a with the holder 35 sandwiched therebetween. In addition,
Reference numeral 37 is a wheel cylinder for sandwiching the disk 34 to generate a braking force, which is the knuckle portion 19
It is bolted to the inner surface of the.

The left and right bearings 3 of the axle 33 are also provided.
Between 1 and 32, the detected portion 33 by serration processing
A is formed, and a rotation sensor 38 is bolted and fixed to a portion between the left and right bearings 31 and 32 of the bearing case 21. The rotation sensor 38 is a non-contact type of electromagnetic induction type, and its detecting portion 38a faces the detected portion 33a with a predetermined gap.

A front swing arm 39 is pivotally supported at the front end of the lower frame 6 of the vehicle body frame 2 so as to be vertically swingable. The front swing arm 39 includes a pair of left and right pivot arm portions 40, 41 which are connected to each other by the cross member portion 4.
2 and the left arm 40 is connected to the front wheel 1
5 is a substantially h-shaped one in a plan view which is extended to the vicinity of the axle 33 of No. 5. The pivot parts 40a and 41a formed at the rear ends of the left and right pivot arm parts 40 and 41 are tapered bearings 4
The lower frame 6 is rotatably supported by the fulcrum 6a of the lower frame 6 via the shaft 3.

Also, an extension portion 40b of the left arm portion 40.
Is bent inward in the vehicle width direction, and a ball joint 44 is fixed to a boss portion 40c formed at the front end thereof. This ball joint 44 is a rod-shaped stud 44.
A spherical ball 44b is integrally formed at the tip of a and is arranged in the ball case 44c, and the stud 44a faces the vehicle width direction. The ball 44b is on the extension of the steering shaft 20 and the front wheel 15
Is positioned immediately above the axle 33 and the ball case 44c is supported by a ball receiving portion 19a formed above the bearing case 21 of the knuckle portion 19. As a result, the steering knuckle 16 is attached to the front swing arm 3
It can move up and down on an arc having a radius of 9 and can rotate around the axis of the steering shaft 20.

A cushion unit 45 is arranged below the cross member portion 42 of the front swing arm 39 in the vehicle width direction. The cushion unit 45 has a coil spring 45b arranged around a damper 45a, and a substantially convex middle portion 46a of a first link 46 at the left and right ends in the axial direction of the coil spring 45b is a first portion in the vehicle longitudinal direction.
It is rotatably connected around the rotary shaft 47a. The first
The inner convex portion 46b of the link 46 has a holding portion 6b formed at the tip of the lower frame 6 and a second rotating shaft 4 in the vehicle front-rear direction.
7b is rotatably connected, and the outer convex portion 46c is rotatably connected to the lower end of the second link 48 about a third rotation shaft 47c in the vehicle front-rear direction. The holding portions 6b of the lower frame 6 are connected to each other by a cross rod 49, and further connected by a cross plate 50 arranged so as to sandwich the first link 46.

A ball bearing 48a is interposed between the lower end of the second link 48 and the third rotating shaft 47c, and the upper end of the second link 48 has a fourth rotation in the vehicle width direction. It is connected to the boss portion 39a of the front swing arm 39 via a shaft 47d and a ball bearing 48b.
The boss portion 39a is integrally formed at the connecting portion between the cross member portion 42 and the left and right pivot arm portions 40, 41.

Next, the function and effect of this embodiment will be described. In the front wheel suspension system of the present embodiment, when an upward load is applied to the front wheel 15 by a convex portion of the road surface or the like, the front swing arm 39 swings upward around the pivot parts 40a and 41a, and the steering knuckle 16 is rotated. The steering shaft 20 slides upward in the lower steering cylinder 22. At this time, the steering knuckle 1
6, the ball 44b portion of the ball joint 44 moves on an arc having a radius of the front swing arm 39, so that the ball joint 6 slightly rotates about the left and right rotation axes b of the universal joint 24. Further, by swinging the front swing arm 39 upward,
The second link 48 moves up, and along with this, the first link 46
Rotates inwardly around the second rotation shaft 47b, whereby the cushion unit 45 is compressed inward, and the upward load is absorbed by the biasing force of the coil spring 45b.

In the front wheel suspension system performing such an operation, the cushion unit 45 is attached to the front swing arm 3
Since it is arranged below 9 and in front of the pivot parts 40a and 41a in the vehicle width direction, the arrangement position of the cushion unit 45 does not restrict the arrangement position of the engine unit 8. Therefore, the engine unit can be arranged on the front side as compared with the above-mentioned conventional device in which the cushion unit is arranged behind the pivot portion, and the distance between the shafts can be shortened to downsize the vehicle. Further, there is no restriction on the arrangement space of the radiator, the exhaust pipe, etc. unlike the conventional device in which the cushion unit is arranged above the swing arm.

Further, as described above, the cushion unit 45
Is disposed below the front swing arm 39 in the vehicle width direction, the center of gravity can be lowered by the weight of the cushion unit 45. Further, the cross rod 49 and the cross plate 5 arranged in front of and behind the cushion unit 45.
Since the front ends of the lower frames 6 are connected by 0,
The repulsive force of the cushion unit 45 can be received as a tensile force by these both members, and the load on the lower frame 6 can be reduced.

In disposing the cushion unit 45 in front of the pivot parts 40a, 41a and below the front swing arm 39, the boss parts 39a for attaching the cushion unit 45 to the front swing arm 39 are pivoted to the left and right pivots. Since it is formed at the connection point between the arm portions 40 and 41 and the cross member portion 42 that connects them, that is, because it is connected to the portion of the front swing arm 39 having high rigidity, the rigidity corresponding to the repulsive force from the cushion unit 45. Is advantageous in securing. Further, in this case, the cushion unit 45 is provided with a pair of left and right first and first cushion units.
Since it is connected to the front swing arm 39 by the second links 46 and 48, the load can be distributed to the left and right, which is also advantageous in terms of ensuring rigidity.

Further, since the inner convex portion 46b located below the first link 46 is pivotally supported by the lower frame 6, when the steering knuckle 16 contracts and the front swing arm 39 swings upward, That is, when the vehicle height becomes low, the first link 46 rotates inward, and thus the bank angle can be secured large.

Furthermore, the first and second links 46, 4 are also provided.
In arranging 8, the links are arranged so as to be along the direction of the rotational trajectory of the front swing arm 39 when viewed in the vehicle width direction, that is, in the caster direction, so the posture change of the cushion unit 45 can be small. The operability can be improved accordingly.

The vehicle body frame to which the front wheel suspension system of the present invention can be applied is not limited to the diamond type frame as in the above embodiment, but is also applicable to the so-called double cradle type frame shown in FIGS. 8 and 9, for example. it can. The vehicle body frame 51 has the following structure.
A pair of left and right lower frames 53 extending forward is connected to the left and right ends of the rear arm bracket 52, and the front ends of the lower frames 53 are connected to each other by a cross frame 54a. The front portion of the lower frame 53 and the upper end of the rear arm bracket 52 are connected to each other by a pair of left and right connecting plates 54b.
And the left and right plates 54b are connected by the upper frame 55. Reference numeral 56 is a seat rail that supports the seat.

Although not shown, the front portion of the upper frame 55 supports the head pipe 3 via a bracket or the like. Further, the front swing arm 39 is supported by the support portion 53a formed on the front portion of the lower frame 53.
Pivotally supporting the pivot parts 40a and 41a of the lower frame 53, and the inner convex part 46 of the first link 46 at the front end part of the lower frame 53.
Axis b is supported.

[0031]

As described above, according to the front wheel suspension system for a motorcycle according to the present invention, the cushion unit is disposed in the vehicle width direction in front of the pivot point of the front swing arm and near the lower part of the cross member. Therefore, there is no restriction on the arrangement position of the engine unit, there is an effect that the vehicle can be downsized, and it is advantageous in that the front swing arm has a structure having rigidity corresponding to the repulsive force from the cushion unit. effective.

[Brief description of drawings]

FIG. 1 is a plan view showing a front wheel suspension system for a motorcycle according to an embodiment of the present invention.

FIG. 2 is a left side view of the apparatus of the above embodiment.

3 is a sectional view taken along line III-III in FIG.

4 is a sectional view taken along line IV-IV in FIG.

5 is a sectional view taken along line VV of FIG.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a left side view of a motorcycle equipped with the device of the embodiment.

FIG. 8 is a rear perspective view showing a modified example of the vehicle body frame in which the front wheel suspension system of the above-described embodiment can be adopted.

9 is a perspective view of the vehicle body frame of FIG. 8 as seen from the front.

[Explanation of symbols]

 1 Motorcycle 6 Lower Frame (Body Frame) 16 Steering Knuckle (Front Fork) 39 Front Swing Arm 39a Boss (Near Connection Point) 40, 41 Left and Right Pivot Arms 40a, 41a Pivot (Pivot) 40b Extension Part 40c Boss part (front end part of front swing arm) 42 Cross member part 45 Cushion unit 46, 48 First and second links

Claims (1)

[Claims] 1. A front wheel suspension system for a motorcycle, wherein a front swing arm is pivotally supported in a vertically movable manner near a lower portion of an engine of a body frame, and a front knuckle is supported by a front end portion of the front swing arm. The left and right pivot arm portions pivotally supported by the body frame are connected to each other by a cross member portion extending in the vehicle width direction, one of the pivot arm portions is extended forward, and the steering end is operated by the extended end portion. A structure for supporting the knuckle is provided, and a cushion unit is arranged in the vehicle width direction in front of the pivotal fulcrums of the left and right pivot arm parts and near the lower part of the cross member part, and both ends of the cushion unit are arranged. A front wheel suspension system for a motorcycle, wherein the front wheel suspension system is characterized in that the above-mentioned left and right pivot arm sections are connected to each other near a connection point between the cross member sections via a link.