JP2002081486A - Front fork - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front fork having less friction resistance and good machining and assembling property. SOLUTION: The front fork having an inner tube 2 slidably inserted into an outer tube 1 for guiding the outer periphery of the inner tube via a bearing provided in an inside gap 7 at the end of the outer tube in the axial direction comprises a recess 16 formed in the inner periphery inside the end of the outer tube along the axial direction and a ball bearing 14 laid in the recess.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front fork which is interposed between a vehicle body and an axle of a vehicle such as a motorcycle and serves as a shock absorber and a fork for attenuating vibration from a road surface.

[0002]

2. Description of the Related Art In general, a motorcycle such as a motorcycle is provided with a front fork serving also as a shock absorber between a vehicle body and an axle.

In this front fork, for example, a wheel-side outer tube and a vehicle-body-side inner tube are slidably inserted into the outer tube, and a bearing for guiding the inner tube in the axial direction is provided inside the end of the outer tube. Is what it is.

[0004]

In the above-mentioned conventional front fork, it is common to use a cylindrical slide bearing as a bearing to smoothly extend and retract the inner tube.

[0005] However, since the above-mentioned plain bearing is cylindrical, it has a large frictional resistance to the inner tube and adversely affects the expansion and contraction operation of the inner tube.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a front fork with low friction resistance, good workability and easy assembling.

[0007]

Means for Solving the Problems To achieve the above object, a means of the present invention is to provide a bearing in which an inner tube is slidably inserted into an outer tube and is provided in a gap inside an end portion of the outer tube. In the front fork which guides the outer circumference of the inner tube in the axial direction through the inner tube, a recess along the axial direction is formed in the inner circumference at the end of the outer tube, and a ball bearing is interposed in the recess. Things.

In this case, a ball bearing is press-fitted into the inner space at the end of the outer tube, thereby forming a recess along the axial direction on the inner circumference at the end of the outer tube with the ball bearing. It is preferable to intervene.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

The front fork A has a wheel-side outer tube 1 connected to the axle of the vehicle, an inner tube 2 connected to the vehicle body and slidably inserted into the outer tube 1, and a center of the outer tube 1. It comprises a hollow rod 3 standing up into the inner tube 2, and a suspension spring 5 interposed between a cap at the upper end of the inner tube 2 and an upper end guide 4 of the hollow rod 3.

The upper end 1a of the outer tube 1 is enlarged in diameter. A bearing mechanism 6 is provided in an inner gap 7 (see FIG. 5) of the upper end 1a to guide the outer periphery of the inner tube 2 in the axial direction. I have.

A piston portion 8 is provided at a lower portion of the inner tube 2, and a valve 9 for generating a damping force is provided at the piston portion 8. A distance between the piston portion 8 and the guide portion 4 at the time of maximum extension is provided. Spring 10 that works with cushion
Is provided.

An orifice 13 is formed below the hollow rod 3 so as to communicate an internal oil chamber 11 and an external reservoir 12 to generate a damping force on the compression side.

The bearing mechanism 6 comprises one or a plurality of lower ball bearings 14, a washer 19, an intermediate oil seal 15 and an upper dust lip 18.

It is preferable that a plurality of ball bearings 14 are provided in the vertical direction, but one ball bearing may be provided.

The ball bearings 14 are arranged in the circumferential direction as shown in FIGS. 2 and 4, but it is preferable to provide one ball bearing on the front side of the vehicle and two or more ball bearings on the rear side.
The number can be freely selected according to the load.

Next, when assembling the ball bearing 14 into the gap 7, the jig P is used as shown in FIG.

The jig P is an inner peripheral surface 1b of the outer tube 1.
Pipe-shaped lower jig P1 movably inserted along
And an upper jig P2 screwed to the upper end of the jig P1 via a screw 23.

An annular step 20 is provided on the outer periphery of the upper jig P1.
The upper jig P2 is provided with a radial concave portion 21 on the lower end surface and a curved holding portion 22 on the outer peripheral side connected to the concave portion 21.

The ball bearing 14 is preliminarily provided with the stepped portion 2.
0, the concave portion 21 and the holding portion 22,
The jig P2 is held by further lowering the upper jig P2 via 3. At this time, the outer surface of the ball bearing 14 protrudes outward by a length T from the upper jig P2. When the jig P is forced into the outer tube 1 in this state, the ball bearing 14 is forcibly pressed into the gap 7 at the upper end 1a of the outer tube.

At this time, the dimension of the gap 7 is smaller than the dimension in the outer diameter direction when the ball bearing 14 is mounted on the jig P. When the ball bearing 14 is press-fitted, the upper end 1a is formed on the outer surface of the ball bearing 14. A recess 16 is formed along the axial direction on the inner periphery of the ball bearing, and the ball bearing 14 is accommodated in the recess 16 so that movement in the circumferential direction is regulated and held. When the jig P is pulled out, the ball bearing 14 falls off from the recess 16, but when the inner tube 2 is inserted, the ball bearing 14 is inserted again into the gap 7 along the recess 16. The material of the outer tube 1 is preferably formed of aluminum, iron, or the like that is softer than the material of the ball bearing 14 so that the recess 16 is formed.

The portion corresponding to the depression 16 at the upper end 1a of the outer tube 1 is compressed to increase the density and increase the strength. The recess 16 may be formed in advance by cutting along the axial direction on the inner periphery of the gap 7 without using the jig P.

The ball bearing 14 guides the outer periphery of the inner tube 2 by point contact and is used as a main bearing. Although the above embodiment describes an upright type front fork, it goes without saying that the present invention is also applicable to an inverted type front fork.

[0024]

According to the present invention, the following effects can be obtained.

(1) According to the invention of each claim, since the ball bearing is used as the bearing, the outer tube has a point contact with the outer periphery of the inner tube, and the frictional resistance is small, so that the slidability of the inner tube can be improved. .

(2) According to the second aspect of the present invention, since the depression is formed when the ball bearing is press-fitted, the ball bearing is held in the depression and is prevented from moving in the circumferential direction, and the play of the backlash is reduced. Occurrence can be prevented. Further, the end of the outer tube has a depression formed on the inner periphery thereof, and the end is compressed by that amount, so that the density is increased and the strength of this end can be increased.

[Brief description of the drawings]

FIG. 1 is a partially cutaway longitudinal side view of a front fork.

FIG. 2 is a cross-sectional plan view taken along line XX of FIG.

FIG. 3 is an enlarged sectional view of the bearing mechanism of FIG. 1;

FIG. 4 is a partially enlarged sectional view of FIG. 2;

FIG. 5 is an enlarged sectional view of a state where a ball bearing is press-fitted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer tube 1a Upper end part 1b Inner peripheral surface 2 Inner tube 7 Gap 14 Ball bearing 16 Recess 19 Washer P Jig

Claims (2)

[Claims] 1. A front fork in which an inner tube is slidably inserted into an outer tube, and an outer periphery of the inner tube is axially guided through a bearing provided in an inner clearance at an end of the outer tube. A front fork, wherein a recess is formed in the inner periphery of the inner end portion of the outer tube along the axial direction, and a ball bearing is interposed in the recess. 2. A ball bearing is press-fitted into a gap inside the end of the outer tube to form a recess along the axial direction on the inner circumference inside the end of the outer tube, and the ball bearing is interposed in the recess. The front fork according to claim 1, wherein