JPH0995281A - Front wheel suspension device for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of cushion unit, which is required at two positions of right and left in the conventional device, to a half. SOLUTION: A steering shaft 4, which is supported by the same shaft with a head pipe 5 freely to be turned, is used as an outer tube, and an inner tube 24 is inserted into the outer tube so as to form a cushion unit, and a lower end of a push rod 26 connected to the inner tube 24 is connected to an intermediate part of a pivot arm 20. One end of the pivot arm 20 is connected to a front wheel shaft 15, and the other end thereof is journalled to a lower end of a front fork 22 and a pivot 21.

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 device suitable for a small motorcycle such as a scooter.

[0002]

In Japanese Utility Model Laid-Open No. 58-43583, a front fork is provided at the lower end of a steering shaft, and the lower end of the front fork is connected to one end of a link arm.
A front wheel suspension system is shown in which a front axle is supported at the other end of the link arm and a cushion unit is attached between the intermediate part of the link arm and the front fork.

[0003]

The conventional front wheel suspension system requires a pair of left and right cushion units which are vertically arranged with the front wheel sandwiched therebetween. Therefore, the steering moment of inertia generated around the steering axis becomes relatively large, and it has been desired to make the steering moment of inertia smaller in order to realize light handling. In addition, the large number of parts complicates the structure, increases unsprung weight, and limits design freedom.

[0004]

The invention according to claim 1 is
A front fork rotatably supported left and right via a steering shaft rotatably supported on a head pipe, and a front wheel having one end pivotally supported at a lower end of the front fork and rotatably supporting a front wheel at the other end. A front wheel suspension system for a motorcycle, comprising a pivot arm having an axle and a cushion unit connecting the pivot arm and the front fork, wherein the cushion unit is arranged on a steering axis. To do.

According to a second aspect of the present invention, in the front wheel suspension system according to the first aspect, one of the two relatively slidable inner and outer members constituting the cushion unit, which has a lower end protruding from the upper end, has the first shaft. A push rod that connects the lower end to the pivot arm at the second shaft landing point is provided, and the first and second shaft landing points are respectively positioned on the steering axis in a side view. Characterize.

According to a third aspect of the present invention, in the first or second aspect, the steering shaft is also used as a component of the cushion unit.

The invention according to claim 4 is characterized in that, in claim 1 or claim 2, the steering shaft and the cushion unit are formed separately from each other.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment will be described below with reference to the drawings. 1 is a side view of a front wheel suspension device, FIG. 2 is a rear perspective view of the front wheel suspension device, and FIG. 3 is a side view of a front portion of a motorcycle to which the front wheel suspension device is applied.

First, in FIG. 3, a front wheel 1 is supported by a vehicle body frame 3 via a front wheel suspension device 2. A steering shaft 4 to be described later has a head pipe 5 at the front end of the body frame 3.
It is rotatably supported via a handle 6, and a handle 6 is attached to the upper end thereof.

A fuel tank 7 is provided outside on the body frame 3.
Is provided, and the seat 8 is supported behind it.
A winker 9 and a headlight 1 are provided on the upper surface of the fuel tank 7.
0 is provided.

An engine hanger 11 extends downward from the front end of the vehicle body frame 3, and a seat support 12 extends downward from the rear end of the vehicle body frame 3.
A mold engine 9 is supported.

In the drawings, reference numeral 14 is a mission, 15 is a front wheel axle, 16 is a brake disk supported on the rim side, and 1 is a brake disc.
7 is a torque rod, 18 is a brake caliper, and 19 is a front fender.

As is apparent from FIGS. 1 and 2, the front wheel suspension system 2 includes a pivot arm 20, a fork arm 22,
A cushion unit including the connecting member 23, the inner tube 24, and the steering shaft 4, a connecting member 25, and a push rod 26 are provided.

Of these, the pivot arm 20, the front fork 22, the connecting members 23 and 25, and the push rod 2
6 are provided in left and right pairs, respectively.

The front fork 22 extends in the vertical direction,
The upper end is connected to the steering shaft 4 via the connecting member 23.

The steering shaft 4 has the same structure as a cushion unit of an inner-outer double cylinder type which has been conventionally used by a retractable inner tube 24 inside thereof, and the steering shaft 4 in this case is a conventional cushion unit. Corresponds to the outer tube in.

Therefore, the center line of the steering shaft 4, that is, the steering axis C coincides with the center lines of the cushion unit and the head pipe 5, and they are arranged concentrically.

A known hydraulic damping mechanism is provided inside the cushion unit constituted by the steering shaft 4 and the inner tube 24 to absorb the vibration of the front wheel 1.

The lower end of the steering shaft 4 and the inner tube 24
An oil seal 27 is provided in a sliding portion around the inner tube 24, and the inner tube 24 has a connecting member 25 protruding in the left-right direction.
Is provided.

The upper end of the push rod 26 is rotatably connected to the connecting member 25, and the connecting portion serves as a first shaft landing point 28.

The push rod 26 extends vertically in a normal state of the vehicle (in a stationary state before the occupant gets on the occupant), and has a lower end portion rotatably connected to an intermediate portion of the pivot arm 20. The connecting portion is the second shaft attachment point 29.

The first and second shaft landing points 28 and 29 are respectively located on the steering axis C in a normal state of the vehicle in a side view (FIG. 1). If this condition is met,
The push rod 26 may have a linear shape or a curved shape.

Below the inner tube 24, the front fender 19 is supported by the inner tube 24 or the steering shaft 4.

As is apparent from FIG. 2, a boss 30 is provided inside the push rod 26 on one side, and one end 31 of the torque rod 17 is axially attached to the boss 30, and the other end is connected to the middle portion of the caliper bracket 32. It is pivoted.

One end 33 of the caliper bracket 32 is attached around the front wheel axle 15, and the other end 34 is attached with the brake caliper 18 (FIG. 3).

Next, the operation of the present embodiment will be described. The impact applied to the front wheel 1 from the road surface is rotated around the pivot 21 in the counterclockwise direction in FIG. 1, and the push rod 26 is pushed upward to push up the inner tube 24 to be damped by the cushion unit. Let

At this time, since the amount of swing of the push rod 26 is relatively small and the push rod 26 moves up and down substantially along the steering axis C, the operation of the cushion unit is smooth. In addition, the pivot arm 20 and the push rod 26
Represents the relative movements associated with each swing, and
It will be possible at 29. Such an operation is performed in the normal state of the vehicle by setting the first and second shaft landing points 28, 29.
Is maintained if it is positioned on the steering axis C in a side view.

In addition, since only one cushion unit is required to be used along the steering axis C, compared with the conventional case where two cushion units are provided in parallel to each other apart from the steering axis C, steering The moment of inertia is significantly reduced, resulting in lighter handling.

In addition, since the amount of cushion units required to be two in the past is halved to one, the number of parts can be reduced and the unsprung weight can be reduced.
Since the cushion unit is integrated with the steering shaft 4 and the outer tube of the cushion unit is also used as the steering shaft 4, the structure is extremely simple and lightweight.

Further, as compared with the conventional cushion unit, since the push rod 26 can be deformed relatively freely, the degree of freedom in design is increased. Further, since the steering shaft 4 of this embodiment is configured as a cushion unit, it becomes relatively thick and has high rigidity.

It is also possible to dispose the outer tube of the cushion unit separately from the steering shaft 4 and dispose the steering shaft 4 and the cushion unit coaxially with the head pipe 5. In this case, the steering shaft 4 may be hollow, and one end side of a conventionally used telescopic type cushion unit may be inserted therein. In this case, a conventional product can be used, so that versatility is increased.

[Brief description of drawings]

FIG. 1 Side view of front wheel suspension system

FIG. 2 is a rear perspective view of the front wheel suspension system.

[Fig. 3] Front side view of a motorcycle to which a front wheel suspension system is applied

[Explanation of symbols]

1: Front wheels, 2: Front wheel suspension system, 3: Body frame, 4:
Steering shaft, 5: head pipe, 20: pivot arm, 2
1: Pivot, 22: Front fork, 24: Inner tube, 26: Push rod

Claims (4)

[Claims] 1. A front fork rotatably supported left and right through a steering shaft rotatably supported on a head pipe, and one end of the front fork is pivotally supported at its lower end and a front wheel is pivoted at the other end. A front wheel suspension system for a motorcycle, comprising: a pivot arm having a front wheel axle that is freely supported; and a cushion unit that connects the pivot arm and the front fork, wherein the cushion unit is arranged on a steering axis. A front wheel suspension system for a motorcycle, characterized in that 2. A relatively slidable inner and outer member constituting a cushion unit, the upper end of which is connected to a member protruding downward at a first shaft landing point and the lower end of which is a second shaft landing point. Provide a push rod that connects to the pivot arm with
The front wheel suspension system for a motorcycle according to claim 1, wherein the first and second shaft landing points are respectively located on a steering axis in a side view. 3. The front wheel suspension system for a motorcycle according to claim 1 or 2, wherein the steering shaft is also used as a component of the cushion unit. 4. The front wheel suspension system for a motorcycle according to claim 1, wherein the steering shaft and the cushion unit are configured separately.