JPH0239063Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of the Invention) The present invention relates to a front fork with a ball bearing, and particularly to an improvement of the ball bearing thereof.

(Prior art) The front fork of a motorcycle, etc., which consists of a fork pipe slidably inserted and fitted into a bottom case, is installed at an angle at the front of the motorcycle, etc., so it receives the side force during operation, and the fork pipe There is a problem in that uneven contact occurs in the oil seal etc. that slides on the outer periphery, increasing sliding resistance, and especially when the sliding resistance is high at the beginning of operation, the user feels sensually uncomfortable.

Therefore, in order to reduce the sliding resistance at the initial stage of operation, a ball bearing consisting of a plurality of balls held between inner and outer rings, one of which slides against the other, is interposed between the bottom case and the fork pipe. Suggested.

A generally conceivable structure in which such a ball bearing is installed is a bush 1 made by baking polytetrafluoroethylene 116 onto the surface of a metal back metal 120, as shown in FIG.
20 is prepared as a separate piece, and this bush 120 is press-fitted onto the outer periphery of the outer ring 117 on the sliding side. The bush 120 requires a relatively large thickness t' in order to maintain rigidity during press-fitting. On the other hand, due to space constraints, the inner circumference of the outer ring 117 and the bush 12
The width B between the 0 and outer circumferences must be kept to a constant value, so the actual thickness T' of the outer ring 117 must be relatively small, and its strength often becomes a problem, and in the worst case. In this case, cracks may occur in the outer ring 117, and the front fork may not be able to operate as expected. Incidentally, although only the outer ring has been described above, the situation is the same for the inner ring as well.

(Purpose of the invention) The invention was made to achieve the above-mentioned object, and its purpose is to improve durability by increasing the wall thickness of the inner and outer rings of a ball bearing. To provide a front fork with ball bearings that can be used.

(Structure of the invention) In order to achieve the above object, the invention interposes a ball bearing between the bottom case and the fork pipe, which holds a plurality of balls between inner and outer rings, one of which slides against the other. In the front fork with a ball bearing, the inner periphery of the inner ring or the outer periphery of the outer ring is coated with a polytetrafluoroethylene baking bush.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of the main part of a front fork according to the present invention, and FIG. 2 is an enlarged detailed view of section A in FIG. 1.

In a front fork 1 shown in FIG. 1, reference numeral 1 denotes a bottom case with an open upper end, into which a fork pipe 2 is inserted and fitted from above so as to be vertically slidable. Further, a seat pipe 3 whose upper end is open is installed in the lower part of the bottom case 1, and its upper end piston portion 3a is in sliding contact with the inner periphery of the fork pipe 2 as shown. A coil spring 4 is stretched between the upper end of the sheet pipe 3 in the fork pipe 2 and a fork bolt (not shown) screwed onto the upper end of the fork pipe 2.

By the way, bottom case 1 and fork pipe 2
Ball bearings 5 and 6 are interposed at the open end of the bottom case 1 and the lower end of the fork pipe 2, respectively.

The ball bearing 5 is configured by holding a plurality of balls 9 rotatably between an outer ring 7 fitted on the inner periphery of the bottom case 1 and an inner ring 8 fitted on the outer periphery of the fork pipe 2 so as to be vertically slidable. be done. The balls 9 are held regularly at regular pitches on the circumference by a retainer 10, and stopper rings 11 and 12 are fitted to the ends of the inner and outer rings 8 and 7 to prevent the balls 9 from coming off. has been done. and,
Above and below the ball bearing 5 on the inner periphery of the bottom case 1 are ring-shaped stoppers 13 against which the inner ring 8 should come into contact.
14 are fixed respectively.

Also, the ball bearing 6 is connected to the fork pipe 2.
Inner ring 15 and bottom case 1 fixed to the lower end of
It is constructed by rotatably holding a plurality of balls 18 between outer rings 17 which are vertically slidably fitted to the inner periphery via polytetrafluoroethylene baking bushes 16, 16. In addition, in the figure, 19 is a retainer 20,
21 is a stopper ring. Ring-shaped stoppers 22 and 23 are provided above and below the ball bearing 6, respectively, with which the outer ring 17 comes into contact. Therefore, at the initial stage of sliding of the front fork, the front fork slides on the bottom case via the ball bearing, and after the inner or outer ring comes into contact with either the upper or lower stopper, it slides via the bushing. , friction (high-frequency micro-vibration) at the initial stage of sliding is reduced.

On the other hand, an oil seal 24 that slides on the outer periphery of the fork pipe 2 is fitted on the inner periphery of the upper end of the bottom case 1, and a dust seal 25 is provided on the upper end of the bottom case 1. In addition, in the figure,
26 is a rebound spring, and hydraulic oil is sealed in the front fork.

By the way, the outer circumference of the outer ring 17 is partially coated with the polytetrafluoroethylene baking bushes 16, 16, and therefore, the width B between the outer ring 17, the inner circumference, and the outer circumference of the bushes 16 is constant. , if the thickness of the bushing 16 is t as shown in FIG. 2, then the thickness of the outer ring 17 is T=B-t, which is significantly larger than the thickness T' of the conventional outer ring 117 shown in FIG. can be increased. In this way, since the thickness of the outer ring 17 can be increased, the strength and durability of the outer ring 17 can be increased, and problems such as cracking during operation will not occur.

Although only the outer ring 17 of the ball bearing 6 has been described above, the inner circumferential side of the inner ring 8 of the other ball bearing 5 is also partially coated with a polytetrafluoroethylene baked-on bushing. The durability of the inner ring 8 is improved.

(Effects of the invention) As is clear from the above explanation, according to the invention, a ball bearing is formed by holding a plurality of balls between the inner and outer rings, one of which slides against the other, between the bottom case and the fork pipe. In the front fork with ball bearings,
Since the inner periphery of the inner ring or the outer periphery of the outer ring is partially coated with a polytetrafluoroethylene baking bush, the thickness of the sliding inner and outer rings can be increased to improve their durability.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the main part of a front fork according to the present invention, FIG. 2 is an enlarged detailed view of section A in FIG. 1, and FIG. 3 is a view similar to FIG. 2 according to the conventional example. In addition, in the drawing, 1 is a bottom case, 2 is a fork pipe, 3 is a seal pipe, 5, 6 are ball bearings, 7, 17 are outer rings, 8, 15 are inner rings, 16
is a polytetrafluoroethylene baking bush.

Claims (1)

[Scope of utility model registration request] In a front fork with a ball bearing, which is constructed by interposing a ball bearing holding a plurality of balls between inner and outer rings, one of which slides relative to the other, between a bottom case and a fork pipe, the inner ring is A front fork with a ball bearing, characterized in that a polytetrafluoroethylene baking bush is directly coated on the inner circumference or the outer circumference of the outer ring.