JPS6144087A - Damping-force variable type front fork - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a variable damping force front fork designed to increase damping force particularly in a high speed range.

(Prior art) For front forks, especially rod-type front forks, the damping force in the low and medium speed range is generated by valves, square holes, etc., but the damping force in the high speed range is strictly controlled. This required management of the geometric dimensions of each flow path, which was extremely difficult in practice.

(Object of the Invention) The present invention has been made in view of the above, and its object is to provide a variable damping force front panel that can increase the damping force in the high speed range and that can easily control this damping force. There is a fork provided.

(Structure of the Invention) In order to achieve the above object, the present invention provides an oil lock piece on the outer periphery of the lower end of the seat pipe, an oil lock collar on the inner periphery of the lower end of the fork pipe, and a connection between the oil lock collar and the outer periphery of the seat vibe. It is characterized by a constriction section provided in between.

(Implementation 4N) Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a half-cut sectional view of the lower part of a front fork according to the present invention, FIG. 2 is a sectional view taken along line 2-2 in FIG. 1, and FIG. 3 is a partially enlarged sectional view of FIG. 1.

In the front fork (1) shown in FIG.

(2) is a bottom case which is open at the top, into which a fork pipe (3) is inserted and fitted from above so as to be vertically slidable. Further, a seat pipe (0) is installed at the bottom of the bottom case (2), and although not shown, the upper end piston part of this is in sliding contact with the inner periphery of the fork pipe (3). Inside the pipe (0), a rod (5) fixed to the upper end of the fork pipe (3) faces from above, and at the lower end of the rod (5) there is a seat pipe (4) that slides up and down on the inner periphery. Piston (8) that fits freely
) are tied together. Note that this piston (8) is provided with a valve mechanism (7) that generates a damping force.

Furthermore, an oil lock piece (8) is fitted around the lower end of the seat pipe (4).
A bottom piece (8) is fitted in the white lower part, and a valve mechanism (10) that generates a damping force is provided on the upper outer periphery of the bottom piece (8).

There is an oil hole (8) diagonally on the side wall of the bottom piece (9).
a) is bored, and an adjuster (11) with a needle-shaped tip is screwed into the bottom piece (8) so as to be able to move up and down. It engages with a dynamically driven dial (12).

On the other hand, an oil lock collar (13) is fitted to the inner periphery of the lower end of the fork pipe (3). This oil lock collar (13) also acts as a rebound receiving member, and a bulge (13a) projecting inward is formed at its upper part as shown in FIG. A constricted portion (10) is formed between the seat pipe (4) and the outer peripheral surface of the seat pipe (4).

Thus, oil chambers (A), (B), (C), and (D) filled with hydraulic oil are defined within the front fork (1).

Next, to explain the function of this front fork (1), in the compression process, the rod (5) and piston (6) move inside the seat pipe (4), and the fork pipe (3) moves inside the bottom case (2). As they move downward, the hydraulic oil in the oil chamber (B) flows through the throttle part (14) to the oil chamber (^), and the hydraulic oil in the oil chamber (C) flows through the valve (
The oil chamber (
Enter B) and squeeze! (14), the damping force is obtained by the resistance when passing through the valve (10) and the oil hole (9a).

In addition, during the extension stroke, the hydraulic oil in the oil chamber (A) passes through the throttle part (14) to the oil chamber (B), and the hydraulic oil in the oil chamber (B) passes through the orifice hole formed in the valve (7). Go through the oil room (
Enter C). As a result, the damping force characteristics in the compression stroke and the extension stroke are different, and this makes it extremely suitable for a front fork to be mounted on a motocross type bike with a compression speed of 10 m/s and an extension speed of 1.5 layers/S, for example. Damping force can be obtained.

FIG. 4 is a half-cut sectional view of the lower part of the font fork according to another embodiment, and in this embodiment, the sheet pipe (
A tapered surface (4a) that gradually expands downward in a part of the outer circumferential surface of the oil lock collar (13) that forms a constricted part (14) with the bulge (13a) of the oil lock collar (13).
) With such a configuration, damping force characteristics that depend on the position of the fork pipe (3) with respect to the bottom case (2) can be obtained.

(Effects of the Invention) As is clear from the above description, according to the present invention, an oil lock piece is provided on the outer circumference of the lower end of the seat pipe, an oil lock collar is provided on the inner circumference of the lower end of the fork pipe, and the oil lock collar is connected to the outer circumferential surface of the seat pipe. Since a bulge is provided to form a constriction between the parts, the desired damping force can be obtained by reducing the number of parts and simplifying the structure.In particular, the dimensions of the constriction are strictly controlled during manufacturing. Therefore, the damping force value can be easily controlled.

[Brief explanation of the drawing]

FIG. 1 is a half-cut sectional view of a front fork according to the present invention;
2 is a sectional view taken along line 2--2 in FIG. 1, FIG. 3 is a partially enlarged sectional view of FIG. 1, and FIG. 4 is a half-cut sectional view similar to FIG. 1 showing another embodiment. In the drawings, (1) is the front fork, (2) is the bottom case, (3) is the fork pipe, (4) is the seat pipe, (8) is the oil lock piece, (13) is the oil lock collar, and (13a) is the front fork. ) is a bulging part, and (14) is a constricted part. Patent applicant Showa Seisakusho Co., Ltd. Agent
Patent Attorney Part 2 1) Part 1 Patent Attorney
Kuni Ohashi, Patent Attorney Koyama
Knotted 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) In a front fork in which a fork pipe is slidably inserted and fitted into a bottom case, and an upper end piston part of a seat pipe planted in the inner bottom of the bottom case slides into contact with the inner periphery of the fork pipe, the seat pipe An oil lock piece is provided on the outer periphery of the lower end, and an oil lock collar is provided on the inner periphery of the lower end of the fork pipe, and a part of the oil lock collar bulges inward to create a connection between this bulge and the outer periphery of the seat pipe. A variable damping force front fork characterized by a constricted part formed between the parts. (2) The variable damping force type front fork according to claim 1, wherein the lower outer circumferential surface of the seat pipe is a tapered surface that widens downward.