JPH02300536A - Oil lock mechanism for inverted front fork - Google Patents

Abstract

PURPOSE:To ensure an oil lock action by attaching an oil lock member adapted to be fitted in an annular oil chamber at a stroke position near to the most compressed position of a front fork so as to define an oil lock chamber thereunder. CONSTITUTION:When a front fork comes to a most compressed position on its stroke, an oil lock collar 16 is fitted on an oil lock piece 8 so as to eliminate a gap to define an oil chamber S4' which is communicated with an oil chamber S3 through an oil hole 14 while oil chambers S1, S2, S3, S4' are closed at the time when the oil lock collar 16 is fitted on the oil lock piece 8 so as to have internal pressure equal to each other. Accordingly, they serve as oil lock chambers to inhibit the front fork from further moving. Thus, the oil lock chambers having no leakage may be defined in comparison with a conventional arrangement, and further, the bulks of the oil lock chambers may be increased, thereby it is possible to ensure an oil lock action.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an oil lock mechanism for an inverted front fork.

(Prior technology) An inverted front fork, in which an inner tube that is attached to the axle side from below is inserted into an outer tube that is attached to the vehicle body, has a shorter stroke than a royal front fork that has a fork pipe inserted from above into the bottom case. Because it has the advantage of being large, it is widely used as the front fork of motorcycles, etc.

An oil lock mechanism disclosed in US Pat. No. 4,561,669 is known as an oil lock mechanism for preventing collisions between members of an inverted front fork when it is fully compressed. This oil lock mechanism involves inserting a piston rod attached to an outer tube from above into a damper cylinder placed inside an inner tube, providing an oil lock collar at the upper end of the damper cylinder, and installing an oil lock piece at the top of the piston rod. The oil lock piece is fitted into the oil lock collar at the stroke position near the maximum compression of the front fork to exert the oil lock effect.

(Problems to be Solved by the Invention) In the conventional oil lock mechanism described above, a small amount of hydraulic oil flows into the damper cylinder from between the piston rod and the rod guide at the bottom of the oil lock chamber, so that the oil lock effect is impaired. In addition, since the oil lock collar is disposed at the upper end of the damper cylinder, it is not possible to form an oil lock chamber with sufficient volume. Furthermore, since the gas chamber is formed in the upper part of the outer tube, the oil lock chamber traps air bubbles, making the oil lock characteristics unstable.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an inverted front fork in which an inner tube attached to the axle side is inserted from below into an outer tube attached to the vehicle body side. A first oil lock member is attached to the inner tube or a member that moves up and down integrally with the outer tube, and a second oil lock member is attached to the outer tube or a member that moves up and down integrally with the outer tube. Maximum compression (at a near stroke position and below the oil level in the oil chamber,
The first and second oil lock members are fitted together.

(Function) When the front fork is compressed and its stroke position approaches the maximum compression position, the second oil lock member provided on the outer tube side engages with the first oil lock member provided on the inner tube side, thereby locking the oil. Acts as a lock.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall view of an inverted front fork using an oil lock mechanism according to the present invention, and FIGS. 2 and 3 are enlarged views of essential parts of FIG. 1 showing the operation of the oil lock mechanism.

In the front fork, an inner tube 2 is slidably inserted into an outer tube 1 from below through a bush 3 and an oil seal 4, and an axle mounting bracket 5 is fixed to the lower end of the inner tube 2.

A cylindrical body 6 whose upper part is constricted and whose lower half is press-fitted and fixed into the inner tube 2 is disposed at the bottom of the inner tube 2, and a damper cylinder is attached to a threaded part carved inside the upper end of the cylindrical body 6. 7 The lower ends are screwed together. The outer periphery of the damper cylinder 7 has a tapered upper portion which is a first oil lock member. An oil lock piece 8 is provided, and a rod guide 9 is provided at the upper end of the damper cylinder 7. A piston rod 10 whose upper end is connected to the outer tube 1 is inserted through the rod guide 9. A piston that slides on the inner peripheral surface of the damper cylinder 7 is fixed to the lower end of the damper cylinder 7. Here, the piston rod 10 is hollow and has an operating rod for adjusting damping force inserted therein.

The inside of the damper cylinder 7 is defined by the piston 11 into oil chambers St and S2, and below the oil chamber S2 is defined an oil chamber S3 by a bottom valve 13. It communicates with the chamber S3 through an oil hole 14 drilled in the cylinder 6, and the upper part of the oil chamber S4 is connected to the gas chamber S5.
It becomes.

Moreover, a seat pipe 15 as a pipe member whose upper end is fixed to the outer tube 1 faces between the inner tube 2 and the damper cylinder 7, and the lower end of this seat pipe 15 has an oil locking member serving as a second oil lock member. Lock collar 16 is installed. This oil lock collar 16 has a stepped portion in the middle, and this stepped portion is used as a spring seat 17, and this spring seat 17 and the cylindrical body 6
A suspension spring 19 is compressed between the lower spring seat 18 and the inner tube 2.

Furthermore, a bushing 20 is fitted around the outer periphery of the spring seat 17, and the seat pipe 15 fixed to the outer tube 1 side and the spring seat 17 slide on the inner periphery of the inner tube 2 via the bushing 20. 21 is a seat pipe! This is the opening drilled at 5.

In the above, when the front fork is compressed from the state shown in FIG.
The hydraulic oil in the oil chamber S4 flows into the oil chamber St through the bottom valve 13, the oil chamber S3, and the oil hole 14, and the hydraulic oil in the oil chamber S4 flows into the damper cylinder. 7 and moves upward through the gap g between the outer circumferential surface and the inner circumferential surface of the oil lock collar 16. Then, when the stroke of the front fork approaches the maximum compression position, the oil lock collar 16 fits into the oil lock piece 8 as shown in FIG. 3, the gap g disappears, and an oil chamber S4'' is defined.Here, Oil room S
4° communicates with the oil chamber S3 through the oil hole 14, but when the oil lock collar 16 and the oil lock collar 8 are fitted, the oil chambers S1, S2. S3 and S4° are sealed and have the same pressure, and act as an oil lock chamber, preventing further compression of the front fork.

Further, as shown in FIG. 4, a volume compensation chamber is formed in the damper cylinder 7 by a bladder, and the damper cylinder 7
In a front fork of a type in which the oil chamber S4 on the outer periphery and the oil chamber S3 inside the damper cylinder 7 do not communicate with each other, only the oil chamber outside the damper cylinder serves as an oil lock chamber.

FIGS. 5 and 8 show another embodiment, and are shown in a simplified manner to make the structure easier to understand.

That is, the embodiment shown in FIG. 5 is similar to the first embodiment in that the damper cylinder 7 is fixed to the inner tube 2 side and the piston rod 10 is fixed to the outer tube 1 side, but the inner tube An oil lock piece 8 is disposed on the inner periphery of the damper cylinder 7, and an oil lock collar 16 that fits into the oil lock piece 8 is slid on the outer periphery of the damper cylinder 7.

Furthermore, in the embodiment shown in FIG. 6, unlike the previous embodiment, the damper cylinder 7 is fixed to the outer tube 1 side, the piston rod 10 is fixed to the inner tube 2 side, and the piston rod 10 and the inner An oil lock piece 8 is disposed between the inner tube 2 and the inner tube 2, and an oil lock collar 16 that fits into the oil lock collar 8 is slid onto the inner peripheral surface of the inner tube 2.

Furthermore, in the embodiment shown in FIG. 7, the damper cylinder 7 is fixed to the outer tube 1 side, and the piston rod 1
0 is fixed to the inner tube 2 side, which is similar to the embodiment shown in FIG. A pipe member 15 partially provided with an oil lock collar 16 is brought into contact with the outer peripheral surface of the damper cylinder 7.

Furthermore, the embodiment shown in FIG. 8 is a modification of the first embodiment shown in FIGS. 1 to N3. That is, in the first embodiment,
Although the oil lock piece 8 is provided extending upward from the bottom of the damper cylinder 7, in this embodiment, the oil lock piece 8 is fixed in the middle of the damper cylinder 7 via a stopper ring.

Even with the above configuration, when the front fork is compressed to a position close to maximum compression, the oil lock collar 15 fits into the oil lock piece 8 to perform an oil lock action.

In the illustrated example, the seat pipe 15 is connected to the outer tube 1, but in the first BL and the second embodiment, the seat pipe 15 is connected to the piston rod 10.
In the '43 embodiment, the seat pipe 15
may be attached to and supported by the damper cylinder 7.

Also, instead of using a part of the oil lock collar 16 as the spring seat 17, the suspension spring 19 is placed in a different location, such as a damper.
A spring seat may be provided on the outer periphery of the cylinder 7 and compressed between this spring seat and the upper end of the actor tube or the lower end of the inner tube.Furthermore, the oil hole 14 formed in the cylinder 6 may be formed in another part. Good too.

(Effects of the Invention) As explained above, according to the present invention, in an inverted front fork, the first oil lock member is provided on the inner circumference of the inner tube or the outer circumference of the damper cylinder, and the first oil lock member is provided on the inner circumference of the inner tube or the outer circumference of the damper cylinder, and Since the second oil lock member is provided on the member that moves up and down, it is possible to define an oil lock chamber that is free from oil temperature compared to conventional oil lock mechanisms.Moreover, the volume of the oil lock chamber can be increased, which improves the oil lock effect. will be ensured.

[Brief explanation of drawings]

Fig. 1 is an overall view of an inverted front fork to which the oil lock mechanism according to the present invention is applied, Figs. 2 and 3 are enlarged views of main parts of Fig. 1 showing the action of the oil lock mechanism, and Fig. 4 Figures 8 through 8 are schematic diagrams showing another embodiment. In the drawings, 1 is an outer tube, 2 is an inner tube, 7 is a damper cylinder, 8 is a first oil lock member, 10 is a piston rod, 15 is a pipe member, 16 is a second oil lock member, [9 is It is a suspension spring. Patent applicant Showa Seisakusho Co., Ltd. Agent
Patent Attorney Part 2 1) Part 1 Patent Attorney
Kuni Ohashi Patent Attorney Small
Yama Yes procedure amendment (voluntary) November 7th, 1999:, 3

Claims (5)

[Claims] (1) Insert the inner tube that is attached to the axle side from below into the outer tube that is attached to the vehicle body side, the damper cylinder is fixed inside the inner tube, and the piston that slides inside the damper cylinder is installed on the outer tube. In an inverted front fork in which the upper end of a piston rod attached to the lower end is connected, a first oil lock member is disposed on the outer periphery of the damper cylinder, a pipe member is attached to the outer tube or the piston rod, and the pipe member is attached to the outer tube or the piston rod. A second oil lock member is provided at the lower end of the member, and is in sliding contact with the inner circumferential surface of the inner tube and is fitted into the first oil lock member to form an oil lock chamber at a stroke position close to the maximum compression of the front fork. The inverted front fork features an oil lock mechanism. (2) Insert the inner tube attached to the axle side from below into the outer tube attached to the vehicle body side,
In an inverted front fork, a damper cylinder is fixedly installed in the inner tube, and the upper end of the piston rod, which has a piston attached to the lower end that slides inside the damper cylinder, is connected to the outer tube. A first oil lock member is provided, a pipe member is attached to the outer tube or the piston rod, and the lower end of the pipe member is in sliding contact with the outer peripheral surface of the damper cylinder and at a stroke position close to the maximum compression of the front fork. An oil lock mechanism for an inverted front fork, characterized in that a second oil lock member is provided which fits into the first oil lock member to form an oil lock chamber. (3) Insert the inner tube attached to the axle side from below into the outer tube attached to the vehicle body side,
In an inverted front fork, a damper cylinder is fixed in the outer tube, and the lower end of the piston rod is attached to the upper end of the inner tube, and a piston that slides inside the damper cylinder is attached to the inner tube. A first oil lock member is disposed on the outer tube or damper cylinder, a pipe member is attached to the outer tube or the damper cylinder, and the lower end of the pipe member is in sliding contact with the inner circumferential surface of the inner tube and is close to the maximum compression of the front fork. a second oil lock member that fits into the first oil lock member at the stroke position to form an oil lock chamber;
An oil lock mechanism for an inverted front fork characterized by having an oil lock member. (4) Insert the inner tube that will be attached to the axle from below into the outer tube that will be attached to the vehicle body,
In an inverted front fork, a damper cylinder is disposed in the outer tube, and the lower end of a piston rod, which has a piston attached to the upper end that slides inside the damper cylinder, is connected to the inner tube. A first oil lock member is provided, a pipe member is attached to the outer tube or the damper cylinder, and the lower end of the pipe member is in contact with the outer circumferential surface of the damper cylinder and at a stroke position close to the maximum compression of the proto fork. An oil lock mechanism for an inverted front fork, characterized in that a second oil lock member is provided which fits into the first oil lock member to form an oil lock chamber. (5) A portion of the second oil lock member is a spring seat that supports one end of a suspension spring that biases the outer tube and the inner tube in the extension direction. An oil lock mechanism for an inverted front fork as described in any of the above.