JP2863595B2 - Upper arm pivot structure of front wheel suspension system for motorcycle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an upper arm pivot structure of a front wheel suspension device for a motorcycle, and more particularly, to an upper arm, a steering knuckle and a so-called double wishbone type front wheel suspension device. Related to the pivot structure.

(Prior Art) As the above-mentioned front wheel suspension device, there is one disclosed in Japanese Patent Application Laid-Open No. Sho 62-31580.

According to the above publication, a lower arm and an upper arm constituting a parallel link are pivotally supported at the front of the body frame so as to be vertically swingable. A steering knuckle that supports the front wheels is supported at the swinging ends of these two arms via ball joints, respectively, and the front wheels can be steered with the steering knuckles around a steering axis connecting the two ball joints. .

The ball joint interposed between the upper arm and the steering knuckle includes a ball, a ball receiver having a ball insertion hole for rotatably inserting the ball therein, and a joint shaft projecting from the ball and the ball receiver. It is configured.

The joint shaft projecting from the ball is positioned substantially coaxially with the steering axis and is fixed to an upper portion of the steering knuckle located above the front wheel, while the joint shaft projecting from the ball receiver is It is fixed to the swinging end of the upper arm. The crossing angle between the steering axis and the axis of the joint shaft fixed to the upper arm is substantially a right angle in side view.

When the front wheel is steered along with the steering knuckle around the steering axis while the motorcycle is running, the motorcycle is steered.

(Problems to be Solved by the Invention) By the way, in the above-mentioned conventional technology, the sliding portions of the ball and the ball receiver in the ball joint are exposed to the outside when viewed from the front wheel side.

For this reason, while the motorcycle is running, pebbles or mud that has been flipped up or rolled up by the front wheel is likely to directly collide with the sliding contact portion, and the sliding contact portion is damaged early. There is a risk.

(Purpose of the Invention) The present invention has been made in view of the above-mentioned circumstances, and is directed to an upper arm pivotally supported by a body frame.
When the steering knuckle that supports the front wheel is steerably supported by a ball joint, pebbles or the like that are flipped up or rolled up by the front wheel are brought into sliding contact between the ball and the ball receiver in the ball joint. It is an object of the present invention to prevent a direct collision, thereby suppressing damage to the sliding contact portion.

(Structure of the Invention) A feature of the present invention for achieving the above object is that a lower arm 31 and an upper arm 34 constituting a parallel link at the front portion of the body frame 2 are pivotally supported so as to be vertically swingable. The steering knuckles 30 supporting the front wheel 4 are supported on the swinging ends of the arms 31 and 34 via ball joints 32 and 37, respectively.
A ball joint interposed between the upper arm 34 and the steering knuckle 30 so that the front wheel 4 can be steered with the steering knuckle 30 around the steering axis A
37 comprises a ball 48, a ball receiver 49 having a ball insertion hole 49a for rotatably fitting the ball 48 therein, and joint shafts 50 and 51 projecting from the ball 48 and the ball receiver 49, respectively. A joint shaft 50 projecting from the ball 48 is positioned substantially coaxially with the steering axis A and is fixed to an upper portion of the steering knuckle 30 located above the front wheel 4, while projecting from the ball receiver 49. The joint shaft 51 is fixed to the swinging end of the upper arm 34, and the intersection angle β between the steering axis A and the axis of the joint shaft 51 fixed to the upper arm 34 is substantially perpendicular to the side view. In the upper arm pivot structure of the front wheel suspension device for a motorcycle, 1) the ball 48 is disposed below the upper portion of the steering knuckle 30 and the joy is directed upward from the ball 48; While projecting the bets shaft 50, the ball insertion hole
49a is a bottomed hole that opens upward from the ball receiver 49. 2) A recess 56 that opens downward is formed in the upper part of the steering knuckle 30, and the ball fits into the recess 56. The point is that an opening 49b above the hole 49a is provided.

(Operation) The operation of the above configuration is as follows.

1) A ball 48 is provided below the upper portion of the steering knuckle 30 and the joint shaft 50 is projected upward from the ball 48 to fix the joint shaft 50 to the upper portion of the steering knuckle 30. A ball fitting hole 49a for fitting the ball 48 therein is a bottomed hole that opens upward from the ball receiver 49.

Therefore, the ball 48 in the ball joint 37 is
The sliding portion between the ball receiver 49 and the ball receiver 49 is covered by the ball receiver 49 from below.

Therefore, while the motorcycle 1 is traveling, pebbles and the like that are flipped up or rolled up by the front wheel 4 are prevented from directly colliding with the sliding contact portion.

2) A recess 56 that opens downward is formed in the upper portion of the steering knuckle 30, and an opening 49b that is above the ball fitting hole 49a is provided inside the recess 56.

Therefore, the sliding contact portion is covered by the upper portion of the steering knuckle 30 from above and from the outside in the horizontal direction.

Therefore, the direct collision of the pebbles or the like from the front wheel 4 side with the sliding contact portion is more reliably prevented by the upper portion of the steering knuckle 30.

Further, as described above, since the opening 49b is provided inside the recess 56, the ball receiver 49 is provided inside the recess 56.
At least the upper part of it.

Therefore, as described above, the upper surface of the front wheel 4 and the steering knuckle
The upper part of 30 can be made closer to each other in the vertical direction.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 2, reference numeral 1 denotes a motorcycle, 2 denotes a body frame, and a front wheel suspension device 3
The front wheel 4 is supported by the front wheel suspension device 3 so as to be steerable. A handle 5 is provided above the front wheel suspension device 3.

On the other hand, a rear wheel suspension 6
Is supported. The rear wheel suspension device 6 has a rear arm 7 pivotally supported by a pivot 8 at the rear of the vehicle body frame 2. A rear wheel 9 is supported on the swinging end of the rear arm 7. A shock absorber 10 is provided between the rear portion of the body frame 2 and the rear arm 7.
The shock absorber 10 absorbs an impact transmitted from the rear wheel 9 to the vehicle body frame 2 side.

An engine 12 is supported on the body frame 2. The engine 12 has a crankcase 12a, a cylinder 12c protruding forward and upward from the crankcase 12a, and a head cover 12b attached to an upper end of the cylinder 12c, and a power transmission device 13 is provided at a rear portion of the crankcase 12a. It is installed continuously. The power of the engine 12 is transmitted to the rear wheels 9 via the power transmission device 13 so that the motorcycle 1 can travel.

Also, a fuel tank 14 for the engine 12 is provided,
This fuel tank 14 is located above the engine 12 and the power transmission device 13. Further, a seat 15 for a rider is provided so as to be connected to the rear of the fuel tank 14. The rider rides on the seat 15 with the rider straddling it. Knee grips 16 for the rider are formed on the rear side surfaces of the fuel tank 14. In addition, 17 is cowling.

The body frame 2 will be described in more detail with reference to FIGS. 2 to 4 and FIG.

The body frame 2 has a pair of left and right main frames 20, 20, and each of the main frames 20 has a substantially U shape in a side view. Each of these main frames 20 has a bracket 21 protruding downward at the front end thereof. A front cross member 22 formed of a circular pipe is disposed between the left and right brackets 21, 21, and a flange 23 attached to each end of the front cross member 22 is detachably attached to each bracket 21 by a bolt 24. Screwed. In other words, the left and right main frames 2 are
The front portions of 0,20 are firmly connected to each other. Also,
The rear portions of the main frames 20, 20 are firmly connected by a rear cross member 25.

At the rear ends of the left and right main frames 20, 20, a rear arm bracket 26 for pivotally supporting the rear arm 7 is protruded. The rear arm bracket 26 pivotally supports the rear arm 7. A rear frame 27 projects from the rear of the main frames 20, 20 toward the rear and upper direction.
The sheet 15 is supported by 27.

The engine 12 and the power transmission device 13 are detachably screwed to the main frames 20 and the rear arm bracket 26 by mounting bolts 28 and are supported on the vehicle body frame 2.

1 to 6, the front wheel suspension 3
Will be described in detail.

The front wheel suspension device 3 is of a so-called double wishbone type and has a steering knuckle 30;
The front wheel 4 is supported on the lower end of the steering knuckle 30 as described above. On the other hand, a lower arm 31 is pivotally supported on the front cross member 22 by a pivot shaft 33 so that the lower arm 31 can swing up and down.
A lower end of the steering knuckle 30 is pivotally supported by 32.

An upper arm 34 is pivotally supported on the front upper portion of the main frames 20 and 20 by a pivot shaft 35 so as to be vertically swingable. The steering knuckle is attached to the front swing end of the upper arm 34.
The upper end of 30 is pivotally supported by another ball joint 37.

The lower arm 31 and the upper arm 34 form a parallel link, which is a steering knuckle 30.
Are pivotally supported on the main frames 20 and 20 so as to be vertically swingable. Further, the above-mentioned two ball joints 32 and 37 are located on a steering axis A which is a longitudinal axis inclined backward, and the front wheel 4 can be steered via a steering knuckle 30 which rotates around the axis A. Have been. As shown in FIG. 3, the angle between the steering axis A and the vertical axis is the caster angle α.

A shock absorber 36 is provided between the front upper portion of the main frame 20 and the lower arm 31, and the shock absorber 36 holds the lower arm 31 in a predetermined posture, that is, while holding the steering knuckle 30 in a predetermined posture. In addition, the shock absorbing from the front wheels 4 to the vehicle body frame 2 is absorbed.

The body frame 2 has a steering frame 38 having a triangular shape in a side view and protruding forward and upward from front portions of the main frames 20 and 20. A head pipe 39 is attached to a protruding end of the steering frame 38, and the head pipe 39 supports the handle 5 so as to be steerable.

Telescopic interlocking means 40 is interposed between the handle 5 and the steering knuckle 30. The interlocking means 40 includes a pair of front and rear shafts 43, 43 attached to the handle 5 via a leaf spring 42, and a case 45 connected to the upper end of the steering knuckle 30 via a leaf spring 44.
Each shaft 43 is slidably fitted in a case 45.

When the steering wheel 5 is steered, the front wheels 4 are steered via the interlocking means 40 and the steering knuckle 30. Also, the front knuckle 30 and the front wheels 4
The change in the relative position between the steering knuckle 30 and the handle 5 when the shaft swings up and down is absorbed by the shaft 43 and the case 45 sliding in the interlocking means 40 with each other. Further, a change in the inclination generated between the steering knuckle 30, the handle 5, and the interlocking means 40 is absorbed by the respective plate springs 42, 44 being elastically bent.

1, 5, and 6, a portion where the upper end of the steering knuckle 30 and the front swinging end of the upper arm 34 are pivotally supported via a ball joint 37 will be described.

The ball joint 37 is composed of a ball 48 and the ball 48
The ball insertion hole 49 that allows the inner part to be rotatably fitted around its center.
A ball receiver 49 having a, and joint shafts 50 and 51 protruding from the ball 48 and the ball receiver 49, respectively.

The upper portion of the steering knuckle 30 extends in the vehicle width direction and is located above the front wheel 4. The ball 48 is disposed below the upper portion of the steering knuckle 30 and above the front wheel 4. The joint shaft 50 is projected from 48 upward. The joint shaft 50 is formed in a bolt shape, and is fixed to the upper end of the steering knuckle 30 by screwing coaxially with the steering axis A. In addition, the ball insertion hole 49a is
It has a bottomed hole that opens upwards.

On the other hand, the joint shaft 51 protruding from the ball receiver 49 extends rearward and is fixed to the swing end of the upper arm.

On the lower surface side of the upper portion of the steering knuckle 30, a concave portion 56 that opens downward is formed. Inside the concave portion 56, the upper portion of the ball fitting hole 49a is fitted, and the concave portion 56 is formed. An opening 49b above the ball receiver 49 is provided inside 56.

Intersection angle β between the axis of the joint shaft 51 and the steering axis A
Is a stationary state in which a rider having an average weight rides on the motorcycle 1 and has a substantially right angle. From this, the intersection angle between the axes of the joint shafts 50 and 51 is substantially a right angle.

For this reason, the lower arm 31 and the upper arm
34 swings, the intersection angle between the axes of the two joint shafts 50 and 51 changes to an acute angle, and when this progresses, until the ball receiver 49 and the joint shaft 50 come into contact with each other. The amount of change in the crossing angle that can be obtained in the range is sufficiently large.

Therefore, the swing angle of the upper arm 34 increases accordingly, that is, the swing dimension of the front wheel 4 associated with the steering knuckle 30 can be sufficiently taken.

Further, as described above, the steering axis A and the joint axis 51
Is substantially a right angle, and the steering axis A is a vertical axis inclined backward. Therefore, the joint shaft 51 extends rearward and downward from the upper end side of the steering knuckle 30 by an amount corresponding to the inclination of the steering axis A rearward. Therefore, the vehicle body space 53 above the upper arm 34 is expanded correspondingly, so that the degree of freedom in arrangement of the radiator 54 and the like above the lower arm 31 is increased.

(Effects of the Invention) According to the present invention, a lower arm and an upper arm that constitute a parallel link at the front portion of a body frame are pivotally supported so as to be able to swing up and down, and the swinging ends of both arms are respectively connected via ball joints. The steering knuckle supporting the front wheel is supported, the front wheel can be steered together with the steering knuckle around the steering axis connecting the two ball joints, and the ball joint interposed between the upper arm and the steering knuckle is a ball, A ball receiver having a ball insertion hole for rotatably fitting the ball therein, and a joint shaft projecting from each of the ball and the ball receiver. The joint shaft projecting from the ball is substantially aligned with the steering axis. Upper part of the steering knuckle located coaxially and above the front wheel And a joint shaft protruding from the ball receiver is fixed to the swinging end of the upper arm, and the crossing angle between the steering axis and the axis of the joint shaft fixed to the upper arm is viewed from the side. In the upper arm pivot structure of the front wheel suspension device for a motorcycle, which is substantially at right angles, 1) disposing the ball below an upper portion of the steering knuckle and projecting the joint shaft upward from the ball. The ball insertion hole is a bottomed hole that opens upward from the ball receiver.

Therefore, the sliding portion of the ball joint and the ball receiver in the ball joint is covered with the ball receiver from below.

Therefore, during running of the motorcycle, pebbles and the like that have been flipped up or rolled up by the front wheels are prevented from directly colliding with the sliding contact portion by the ball receiver,
Therefore, the sliding contact portion is prevented from being damaged.

2) A recess which opens downward is formed in the upper part of the steering knuckle, and an opening upward of the ball fitting hole is provided inside the recess.

Therefore, the sliding contact portion is covered by the upper portion of the steering knuckle from above and from the outside in the horizontal direction.

Therefore, direct collision of the pebbles or the like from the front wheel side with the sliding contact portion is more reliably prevented by the upper portion of the steering knuckle, and therefore, the sliding contact portion is damaged. It is more reliably suppressed.

Further, as described above, since the opening is provided inside the recess, at least the upper portion of the ball receiver enters the inside of the recess.

Therefore, as described above, the upper surface of the front wheel and the upper portion of the steering knuckle can be made closer to each other in the vertical direction by the amount of the ball receiver entering the recess, thereby making the front wheel suspension device more compact. be able to.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a partially enlarged sectional view of FIG. 2, FIG. 2 is an overall side view of a motorcycle, FIG. 3 is a partially enlarged view of FIG. 2, and FIG. FIG. 3 is a view taken along the line IV-IV of FIG. 3, FIG. 5 is a view taken along the line VV of FIG. 3, and FIG. 6 is a view taken along the line VI-VI of FIG. DESCRIPTION OF SYMBOLS 1 ... motorcycle, 2 ... body frame, 3 ... front wheel suspension device, 4 ... front wheel, 30 ... steering knuckle, 31
…… Lower arm, 32 …… Ball joint, 34 …… Upper arm, 37 …… Ball joint, 48… Ball, 49…
... Ball receiver, 49A ... Ball insertion hole, 49b ... Opening, 50
... joint shaft, 51 ... joint shaft, 53 ... body space, 54 ... radiator, 56 ... recess, A ... steering axis,
α: caster angle, β: crossing angle.

Claims (1)

(57) [Claims] 1. A steering knuckle in which a lower arm and an upper arm constituting a parallel link are pivotally supported on a front portion of a body frame so as to be vertically swingable, and the front wheels are supported at the swinging ends of both arms via ball joints. And the front wheel can be steered with the steering knuckle around the steering axis connecting the two ball joints.The ball joint interposed between the upper arm and the steering knuckle is used as a ball, and the ball is rotatable. A ball receiver having a ball insertion hole to be internally fitted, and a joint shaft projecting from each of the ball and the ball receiver, and the joint shaft projecting from the ball is positioned substantially coaxially with the steering axis. It is fixed to the upper part of the steering knuckle located above the front wheels. A motorcycle in which a joint shaft protruding from a ball receiver is fixed to a swinging end of an upper arm, and an intersection angle between the steering axis and the axis of the joint shaft fixed to the upper arm is substantially a right angle in a side view. In the upper arm pivot structure of the front wheel suspension device, 1) disposing the ball below the upper portion of the steering knuckle and projecting the joint shaft upward from the ball, A bottomed hole that opens upward from the ball receiver. 2) A recess that opens downward is formed in the upper part of the steering knuckle. Inside the recess, an upward opening of the ball insertion hole is formed. Upper arm pivot structure of the front wheel suspension system for motorcycles provided.