JPH0640372A - Front wheel support device - Google Patents

Abstract

PURPOSE:To provide a front wheel support device provided with a front fork having a sufficient length and not applied with large reaction force to the contact portion between an inner tube and an outer tube from the ground by resolving the problem of a conventional front wheel support device. CONSTITUTION:A front wheel support device is integrally provided with a boss section 13 fixing a wheel shaft 12 at the upper portion than the lower end on the side faced to a front fork 3 on the outer tube 8 of the front fork 3 slidably coupled with an inner tube 7 into the outer tube 8 via metal rings 7c, 8a, and a wheel shaft 12 is held there.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel supporting device used in a motorcycle, and more particularly to a front wheel supporting device having a front fork characterized by a wheel shaft supporting portion.

[0002]

2. Description of the Related Art Conventionally, as a front wheel supporting device for supporting a front wheel of a motorcycle, two tubes are combined in a telescopic manner so that the inner cylinder and the outer cylinder make a stroke while contacting each other, or the inner cylinder. Also, there is a so-called telescopic type in which a metal ring is provided on each of the outer cylinder and a front fork configured to make a stroke while the inner cylinder and the outer cylinder make contact with each other at the position of the metal ring to support the wheel shaft of the front wheel. On the other hand, as a structure for supporting a front wheel by a front fork, a hole in which a wheel shaft of the front wheel is fitted is formed at a lower end of the front fork, and a wheel shaft is installed between the hole and the hole (Japanese Patent Laid-Open Publication No. Sho. 61-178237) or a front part of the lower part (not the lower end) of the front fork, which is provided with a recess into which the wheel shaft is detachably fitted. A type that fixes the wheel shaft (JP-A-61-92981)
There was one.

[0003]

However, the front wheel support device of the type in which the wheel shaft is supported by the lower end of the front fork described above supports the wheel shaft substantially on the axis of the front fork. In the case of such a telescopic type, there is an advantage that the reaction force from the ground on the contact portion between the inner cylinder and the outer cylinder, for example, the metal ring can be reduced.
Since the support portion is provided at the lower end of the front fork, there is a problem that the length of the front fork itself is limited, and as a result, the stroke length is limited. Further, since the front wheel support device of the type that supports the wheel shaft on the front side of the lower part of the front fork described above has no lower limit, the length of the front fork itself, that is, the stroke length of the front fork, can be sufficiently secured. Although it has an advantage, since the position supporting the wheel shaft is offset in the front direction from the axis of the front fork, there is a problem that the reaction force from the ground on the contact portion between the inner cylinder and the outer cylinder, for example, the metal ring, increases. was there.
Therefore, the present invention solves the problems of the conventional front wheel supporting device as described above, the length of the front fork can be sufficiently taken, and the contact portion between the inner cylinder and the outer cylinder, for example, the metal ring is applied. An object of the present invention is to provide a front wheel support device having a front fork that does not increase the reaction force from the ground.

[0004]

In order to achieve the above-mentioned object, a front wheel support device of the present invention is constructed such that an inner cylinder is fitted into an outer cylinder so as to be slidable and a wheel shaft is supported. In a front wheel support device having a front fork,
The wheel shaft is supported at a position above at least the lower end of the front fork facing the front fork.

[0005]

In the front wheel support device constructed as described above, since the wheel shaft is installed between the support parts provided at the lower part of the front fork, more specifically at least above the lower end, the front wheel is supported. The front wheel support portion does not limit the length of the front fork. Also, because the support portion of the wheel shaft is provided on the side facing the front fork, the position supporting the wheel shaft does not offset in the front direction on the axis of the front fork, and the contact portion between the inner cylinder and the outer cylinder does not have to be offset. The reaction force from the excessive ground is not applied.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the front fork of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partially cutaway schematic side view showing a main part of a motorcycle using a front fork which constitutes a front wheel support device of the present invention, and FIG. 2 is a schematic sectional view showing details of a combined state of the front fork and the front wheel,
FIG. 3 is a schematic cross-sectional view of a boss portion and a holding member showing details of a supporting portion of a wheel shaft. Reference numeral 1 in the figure shows a motorcycle, in which a head pipe 2 having a steering shaft (not shown) rotatably fixed and a pair of front forks 3 and 3 are connected by an under bracket 4 and an upper bracket 5. The front wheel 6 is supported between the front forks 3 and 3.

The front fork 3 slidably fits the inner cylinder 7 to the outer cylinder 8 and supports a load by a spring penetrating the inner cylinder 7 and an oil-type shock absorber formed inside to absorb an impact. It is of the so-called Ceriani type, which is configured to absorb. In the figure, 9 is a hollow cylinder whose upper part is slidably fitted inside the inner cylinder 7 and whose lower part is fixed to the bottom part of the outer cylinder 8 with bolts 9a. The oil filled inside is a front fork 3 In response to the expansion and contraction of the oil, the oil flows between the oil chamber 10 and another oil chamber (not shown) provided inside the oil chamber 10 and the inner cylinder 7 to absorb the shock. The inner cylinder 7 is configured by screwing a sliding tube 7b to a hollow support tube 7a formed in a tapered shape so as to expand from both ends in a substantially central direction. An annular metal ring 7c is provided at the bottom. The support pipe 7a is preferably made of a light metal material such as aluminum, and if it is made of such a material, the weight of the front fork can be reduced. The outer cylinder 8 is formed in a hollow cylindrical shape that opens upward, and an annular metal ring 8a and an annular oil seal 8b are fitted to the enlarged portion of the outer cylinder 8 and fixed by a circlip (no reference numeral). However, an annular dust seal 8c is provided at the upper end. The inner cylinder 7 is fitted to the outer cylinder 8 configured as described above so as to come into contact with the metal rings 7c and 8a so as to be slidable, and is exposed to the outside of the sliding pipe 7b constituting the inner cylinder 7. A cylindrical protective cover 11 made of an appropriate material such as resin so as to cover the portion is attached to the outer cylinder 7.
The front fork 3 is fixed to the upper end of the front fork 3, and the front wheel 6 is supported by the lower part of the front fork 3. The upper part of the front fork 3, more specifically, the maximum diameter part of the support pipe 7a forming the inner cylinder 7, is fixed by the under bracket 4.

The front wheel supporting portion of the front fork 3 will be described below. The inside portion of the surface of the outer cylinder 8 constituting the front fork 3 described above, specifically, the front fork 3
A boss portion having an arc-shaped concave portion 13a on which the end portion of the wheel shaft 12 can be detachably fitted
13 are integrally formed. The concave portion of the boss portion 13 described above
After fitting the end of the wheel shaft 12 to 13a, cover the holding member 14 formed in substantially the same shape as the boss 13 and firmly fix the boss 13 and the holding member 14 with the bolts 15 and 15. Thus, the wheel shaft 12, that is, the wheel shaft
The front wheel 6 mounted on the ball 12 through the ball bearing 16 is held by the front fork 3. The front wheel 6 is composed of a wheel 17 and a tire 18, and is fitted to the wheel shaft 12 from the left end portion of the wheel shaft 12 in FIG. 2 and fixed to the wheel shaft 12 with a circlip 19. In the figure, 20 is an annular dust seal, and 21 is an annular positioning collar, both of which are fixed to the wheel shaft 12 side. In the figure, reference numeral 22 is a circlip for fixing the outer member (no reference numeral) of the ball bearing 16 to the wheel, which is fixed to the wheel 17 side.

In this embodiment, the front fork forming the front wheel supporting device is described by using the Ceriani type, but the structure of the front fork is not limited to this, and a pair of front forks are opposed to each other. Any structure may be used as long as the boss portion for mounting the wheel shaft is provided on the surface to be mounted. For example, an upright type having another structure may be used.

In the front fork which constitutes the front wheel support device of this embodiment, the wheel shaft is integrally provided at the boss portion above the lower end of the front fork.
Since it is configured to be held by 12, there is an effect that the front fork can have a sufficient length and the inner cylinder can be configured separately for the sliding pipe and the support pipe. Further, in the front fork constituting the front wheel support device of the present embodiment, the inner cylinder is divided into a sliding pipe and a support pipe,
Expanding the diameter of the support tube from both ends in the substantially central direction,
Since the maximum diameter portion is configured to be held by the under bracket, it is possible to increase the rigidity of the portion held by the under bracket that normally receives a strong bending moment in the front fork.

[0011]

Since the front wheel support device of the present invention is constructed so that the wheel shaft is held at a portion above the lower end of the front fork, the front fork can have a sufficient length and the degree of freedom in design can be increased. The effect is increased. Further, since the front wheel support device of the present invention is configured to hold the wheel shaft on the opposite side of the front fork, even if the wheel shaft is held above the lower end, the contact portion between the inner cylinder and the outer cylinder is not affected. Therefore, the reaction force from the ground does not increase and the operability of the front fork does not decrease. further,
Since the front wheel support device of the present invention is configured to support the wheel shaft on the opposite side of the front fork, the length of the wheel shaft can be made shorter than that of the conventional one, thereby reducing manufacturing cost and weight. The effect of being able to reduce.

[Brief description of drawings]

FIG. 1 is a partially cutaway schematic side view showing a main part of a motorcycle using an embodiment of a front wheel support device of the present invention.

FIG. 2 is a partially cutaway schematic front view showing details of a connecting portion of a front fork and a wheel shaft.

FIG. 3 is a cross-sectional view showing details of a boss portion of a front fork.

[Explanation of symbols]

 1 Motorcycle 2 Head pipe 3 Front fork 4 Under bracket 5 Upper bracket 6 Front wheel 7 Inner tube 7a Support tube 7b Sliding tube 7c Metal ring 8 Outer tube 8a Metal ring 8b Oil seal 8c Dust seal 9 Cylinder 9a Bolt 10 Oil chamber 11 Protection Cover 12 Wheel shaft 13 Boss 13a Recess 14 Holding member 15 Bolt 16 Ball bearing 17 Wheel 18 Tire 19 Circlip 20 Dust seal 21 Positioning collar 22 Circlip

Claims (1)

[Claims] 1. A front wheel support device having a front fork configured to fit an outer cylinder into an outer cylinder so as to be slidable and supporting a wheel shaft, wherein the wheel shaft faces the front fork. A front wheel support device characterized by being supported at a position above at least the lower end of the.