JPH03281490A - Structure for pivotally supporting upper arm of front wheel suspension device for motor-cycle - Google Patents

Abstract

PURPOSE:To enhance an installation space for vehicle body parts by setting the crossing angle between a steering center shaft and a joint shaft secured to an upper arm, to a substantially right angle as viewing toward a side surface, so as to increase the swing angle of the upper arm. CONSTITUTION:A front swingable end part of an upper arm 34 is pivotally connected to the upper end part of a steering knuckle 30 in a front wheel suspension device by means of a ball joint 37. Joint shafts 50, 51 are projected from a ball 48 and a ball receptacle 49, respectively, so as to constitute the ball joint 37. The crossing angle beta between the joint shaft 51 extending rearward and a steering core axis A is set to a substantially right angle in such a condition a rider rides thereon in a static condition. Accordingly, the angle range to the extent such that the ball receptacle 49 and the join shaft 50 make contact with each other due to swinging motion, can be sufficiently enlarged, and accordingly, the dimensions of the front wheel can be increased. Further, the available space in the vehicle body can be enlarged, and accordingly, the arrangement of parts can be facilitated.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an upper arm pivot structure of a front wheel suspension for a motorcycle, and more specifically, to an upper arm and a steering wheel suspension in a so-called double wishbone type front wheel suspension.・Regarding the pivot structure with Nkuru.

(Prior Art) Some of the above-mentioned front wheel suspension systems have conventionally been configured as follows, for example.

That is, the upper arm that constitutes the suspension system extends almost horizontally from the rear end that is pivotally supported on the vehicle body side to the front end that is connected to the steering knuckle, and the front end is connected to the steering knuckle for the front wheels via a ball joint. supports the upper part of the The steering knuckle can be steered around the same axis 6 passing through the ball joint.

In the above configuration, the pole joint usually consists of a pole, a ball receiver into which the pole is rotatably fitted into the center opening of the pole, and joint shafts that respectively protrude from the pole and the ball receiver. . and,
One of these joint shafts is fixed to the upper end of the steering knuckle coaxially with the steering axis, and the other joint shaft is attached to the swinging end of the upper arm along the longitudinal direction of the upper arm. It is fixed in a horizontal position.

(Problems to be Solved by the Invention) Incidentally, the above-mentioned steering axis is a vertical axis tilted backward in order to obtain a predetermined caster angle. For this reason, the above-mentioned - side joint shaft provided coaxially with this steering axis center,
The intersection angle between the axes of the other joint shaft extending in the horizontal direction is an acute angle when viewed from the side.

For this reason, the above-mentioned upper arm swings when driving, etc.
If the crossing angle is about to change to a more acute angle, the pole joint shaft and the ball receiver will interfere with each other while the amount of change in the crossing angle is small, causing the upper arm to swing. may be severely restricted. In other words, with the above configuration, there is a problem in that the vertical swing dimension of the front wheels due to the steering knuckle cannot be sufficiently adjusted.

Furthermore, since it is necessary to provide vehicle body parts such as a radiator above the steering knuckle, it is required to secure as much space as possible.

(Object of the Invention) This invention has been made in view of the above-mentioned circumstances, and is designed to provide a sufficient vertical swing dimension of the front wheel that swings together with the steering knuckle along with the upper arm, and to It is an object of the present invention to provide sufficient body space for installing vehicle body parts above.

(Structure of the Invention) A feature of the present invention for achieving the above object is that the intersection angle between the steering axis and the axis of the joint shaft fixed to the upper arm is approximately perpendicular when viewed from the side. At the point.

(for production) The effect of the ``-2 configuration is as follows.

The intersection angle β between the steering axis A and the axis of the joint shaft 51 fixed to the upper arm 34 is approximately a right angle when viewed from the side. Therefore, the intersection angle between the axial center of the other joint shaft 50, which is provided substantially coaxially with the steering axis A, and the narrow center of the joint shaft 51 is also substantially a right angle.

As a result, the upper arm 34 swings when driving, etc.
In the case where the intersecting angle of both joint shafts 50, 51 changes to an acute angle and this progresses, the above intersecting angle that can be taken within a range that does not cause any trouble due to the structure of the upper ball joint (ball joint) 37. The amount of change will be larger than before.

Therefore, the swing angle of the upper arm 34 can be increased accordingly.

Further, as described above, the intersection angle β between the steering axis A and the axis of the joint shaft 51 is approximately a right angle, and the steering axis A is tilted backward because it is necessary to take a predetermined caster angle α. The vertical axis is Therefore, the joint shaft 51 is
The steering knuckle 3o extends rearward and downward from the upper end side of the steering knuckle 3o by the amount that the steering axis A is tilted rearward.

Therefore, the vehicle body space 53 above the upper arm 34 is expanded by that amount.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, 1 is a motorcycle, 2 is a body frame, a front wheel suspension device 3 is supported at the front of this body frame 2, and a front wheel 4 is supported on this front wheel suspension device 3 so as to be freely steerable. . Further, a handle 5 is provided above the front wheel suspension system 3 as described above.

On the other hand, a rear wheel suspension system 6 is supported at the rear of the vehicle body frame 2. This rear wheel suspension device 6 has a rear arm 7 that is pivotably supported by a pivot shaft 8 at the rear of the vehicle body frame 2 so as to be vertically swingable. A rear wheel 9 is supported at the swinging end of this rear arm 7. A shock absorber 10 is also provided between the rear part of the vehicle body frame 2 and the rear arm 7.
is installed via a link mechanism 11, and this shock absorber 10 absorbs the shock transmitted from the rear wheel 9 to the vehicle body frame 2. An engine 12 is supported on the vehicle body frame 2. The engine 12 includes a crankcase 12a and a cylinder 12 that protrudes forward and upward from the crankcase 12a.
c,! 3 and a head cover 12b attached to the upper end of the cylinder 12C.
A power transmission device 13 is connected to the rear part of a. The power of the engine 12 is transmitted to the rear wheels 9 via the power transmission device 13, allowing the motorcycle l to travel.

Further, a fuel tank 14 for the engine 12 is provided, and this fuel tank 14 is connected to the engine 12 and the power transmission device.
It is located above 3. Furthermore, a lighter seat 15 is provided continuous to the rear of the fuel tank 14. A rider rides on this seat 15 in a straddling position, and knee grip portions 16 for this rider are formed on each rear side of the fuel tank 14. Others, 1
7 is cowling.

The vehicle body frame 2 will be explained in more detail with reference to FIGS. 2 to 4 and 6.

This body frame 2 consists of a pair of left and right main frames 20.20
, and each main frame 20 has a substantially U-shaped shape when viewed from the side. Each of these main frames 20 is provided with a bracket 21 that projects downward at its front end. A front cross member 22 formed of a circular vibrator is disposed between these left and right brackets 21, 21, and flanges 23 attached to each end of this front cross member 22 are detachably attached to each bracket 21 by ports 24. The front portions of the left and right main frames 20, 20 are firmly connected to each other by the front cross member 22 which is screwed. Also, the main frame 20.2
0 are firmly connected to each other by a rear cross member 25.

A rear arm bracket 26 for pivotally supporting the J arm 7 is protruded from the rear end of the left and right main frames 20.20,
The rear arm 7 is pivotally supported on this rear arm bracket 26. Further, a rear frame 27 is provided to protrude rearward and upward from the rear of the main frame 20, 20, and the seas 1-, 15 are supported by this rear frame 27.

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

1 to 6, the front wheel suspension system 3 will be explained in detail.

The front wheel suspension system 3 is of a so-called double wishbone type, and has a steering knuckle 30.
The front wheel 4 is supported at the lower end of this steering wheel bundle 30 as described above. On the other hand, a lower arm 3 is pivotally supported on the front cross member 22 by a pivot shaft 33 so as to be vertically swingable, and a lower pole joint 32 is connected to the front swing end of the lower arm 31 to connect the steering knuckle 3 to the front cross member 22.
The lower end of 0 is pivoted.

Further, an upper arm 34 is pivotally supported at the front upper part of the main frame 20.20 by a pivot shaft 35 so as to be vertically swingable.
The upper end of the steering knuckle 30 is pivotally supported at the front swing end of the upper arm 34 by an upper ball joint 37.

The lower arm 31 and the upper arm 34 constitute a parallel link, which pivotally supports the steering knuckle 30 with respect to the main frame 20, 20 so as to be vertically swingable. Further, the lower pole joint 32 and the upper pole joint 37 are located on the steering axis A, which is a vertical axis tilted backward, and the front wheels is said to be able to be steered. In addition.

As shown in FIG. 3, the angle formed between the steering axis A and the vertical axis is the caster angle a.

A shock absorber 36 is installed between the front upper part of the main frame 20 and the lower arm 31, and this shock absorber 36 holds the lower arm 31 in a predetermined posture, that is, the steering knuckle 30 in a predetermined posture, and also holds the lower arm 31 in a predetermined posture. , absorbs the impact that is about to be transmitted from the front wheels 4 to the vehicle body frame 2 side.

The vehicle body frame 2 has a steering frame 38 which has a triangular shape in side view and projects upward and forward from the front part of the main frame 20.20. A head vibrator 39 is attached to the protruding end of the steering frame 38, and the head vibrator 39 supports the handle 5 so as to be freely steerable.

A telescopic interlocking means 40 is interposed between the handle 5 and the steering knuckle 30. This interlocking means 40 includes a pair of front and rear shaft bodies 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. is slidably fitted into the case 45.

When the steering wheel 5 is operated, the front wheels 4 are steered via the interlocking means 40 and the steering knuckle 3o. Further, when the front wheel 4 swings up and down together with the steering knuckle 30, the change in relative position between the steering knuckle 30 and the handle 5 is controlled by the interlocking means 4o.
In this case, the shaft body 43 and the case 45 slide against each other to absorb the damage. Also, steering knuckle 30
, the handle 5, and the interlocking means 4o are absorbed by the elastic deflection of each leaf spring 42,44.

1, 5, and 6, the portion where the upper end of the steering knuckle 30 and the front swing end of the upper arm 34 are pivotally supported via the upper pole joint 37 will be explained. The upper ball joint 37 is connected to the pole 48.

A ball receiver 49 into which the pawl 48 is rotatably fitted into its center opening;
and a joint shaft 50.5 which respectively protrudes from. The joint shaft 50 of the pawl 48 is in the form of a bolt, and is fixed to the upper end of the steering knuckle 30 coaxially with the steering axis A.

On the other hand, the joint shaft 5I of the ball receiver 49 extends rearward, and the axial center of the joint shaft 5I and the steering axis A
The intersection angle β with 5 is approximately a right angle when the motorcycle l is at rest with a rider of average weight riding on it. Also,
For this reason, the intersecting angle between the axes of both joint shafts 50, 51 is approximately a right angle.

For this reason, when the lower arm 31 and the upper arm 34 swing during driving, etc., and the intersecting angle between the axes of the joint shafts 50 and 51 changes to an acute angle, and this progresses, the ball Receptacle 49 and joint shaft 5
The amount of change in the above-mentioned crossing angle that can be taken in the range up to contact with 0 becomes sufficiently large.

Therefore, the swing angle of the upper arm 34 increases accordingly, and in other words, a sufficient swing dimension of the front wheel 4 due to the steering knuckle 3° can be obtained.

In addition, as described above, the steering axis A and the joint axis 51
The intersecting angle β between the steering axis A and the axis A is approximately a right angle, and the steering axis A is a vertical axis tilted backward.

Therefore, the joint shaft 5I extends rearward and downward from the upper end of the steering knuckle 30 by the amount that the steering wheel A is tilted rearward. Therefore, the vehicle body space 53 above the upper arm 34 is expanded by that amount, and therefore, the degree of freedom in arranging the radiator 54 and the like above the lower arm 31 is increased.

Although the above is based on the illustrated example, the intersecting angle may be approximately a right angle6.Furthermore, the pole 48 may be fixed to the upper arm 34, and the ball receiver 49 may be fixed to the steering knuckle 30.

(Effects of the Invention) According to the present invention, since the intersection angle between the steering axis and the axis of the joint shaft fixed to the upper arm is approximately a right angle in side view, the steering axis The intersection angle between the axial center of the other joint shaft provided substantially coaxially with the axial center of the joint shaft is also substantially a right angle. As a result, the upper arm swings when driving, etc., and the intersecting angle between the axes of the two joint shafts changes to an acute angle, and
As this progresses, the amount of change in the crossing angle that can be taken within a range that does not cause any problems due to the structure of the pole joint will become larger than in the past.

Therefore, the swing angle of the upper arm can be increased accordingly.
In other words, a sufficient amount of swinging of the front wheels due to the steering knuckle can be achieved.

Further, as described above, the angle of intersection between the fine point of the steering axis and the axis of the joint shaft is approximately a right angle, and the steering axis is a vertical axis tilted backward. Therefore, the joint shaft extends rearward and downward from the upper end of the steering knuckle by the amount that the steering axis is tilted rearward, and the vehicle body space above the upper arm is expanded by that amount.

Therefore, when a vehicle body part such as a radiator is to be installed above the lower arm, there is an advantage that the vehicle body part can be easily installed.

(Margin below)

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a partially enlarged sectional view of Fig. 2, Fig. 2 is an overall side view of the motorcycle, Fig. 3 is a partially enlarged view of Fig. 2, and Fig. 4 is a partially enlarged sectional view of Fig. 2. FIG. 3 is a view taken along the line rV-IV in FIG. 3, FIG. 5 is a view taken along the line V-V in FIG. 3, and FIG. 6 is a view taken along the line Vl-VT in FIG. 3. l...Motorcycle, 2...Body frame, 3...Front wheel suspension, 4...Front wheel, 30...Steering knuckle,
31...Lower arm, 32...Lower pole joint, 3
4. Upper arm, 37. Upper pole joint (ball joint), 48-. Ball, 49.. Ball receiver, 50. Joint shaft, 51.- Joint shaft, 53.
Vehicle body space, 54...Radiator, A...Steering axis, α...
・Caster angle, β...Cross angle. Patent applicant: Yamaha Motor Co., Ltd., Figure 9

Claims (1)

[Claims] 1. A lower arm and an upper arm, which form a parallel link, are pivotally supported in the front part of the vehicle body frame so as to be able to swing vertically, and a steering knuckle is supported via a ball joint at the swinging end of each of these arms. The above-mentioned steering knuckle can be steered around a steering axis connecting the joints, and the ball joint interposed between the above-mentioned upper arm and the steering knuckle has a ball, a ball receiver into which the ball is rotatably fitted, and these balls. and a joint shaft protruding from the ball receiver, respectively.One of these joint shafts is fixed to the steering knuckle approximately coaxially with the above-mentioned steering axis, while the other joint shaft is attached to the swing of the upper arm. In the upper arm pivot structure of a front wheel suspension system for a motorcycle fixed to the moving end, the intersection angle between the steering axis and the axis of the joint shaft fixed to the upper arm is almost a right angle in side view. Upper arm pivot structure for front wheel suspension system.