JPH02182592A - Inverted type front fork - Google Patents

Abstract

PURPOSE:To reduce weight and to improve a damping force by a method wherein, in an inverted type front fork for a motorcycle, a partition wall is formed in an inner pipe by which an air chamber on the end side coupled to an axle is partitioned away from an oil chamber on the outer pipe side, and an oil chamber is filled with working oil. CONSTITUTION:In an inverted type front fork A in which an inner pipe 4 is slidable within an outer pipe 1, a partition wall 12 is disposed to the lower part, protruded from the outer pipe 1, of the inner pipe 4 through a snap ring 11 to partition an oil chamber 4a1 from an air chamber 4b. The oil chamber 4a1 is filled with working oil, and the air chamber 4b forms a blocked gap. A hydraulic brake mechanism is situated in the outer pipe 1 to damp slide of the inner pipe 4. This constitution enables reduction of an unnecessary amount of working oil and reduction of weight, and permits reduction of a damping force.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inverted front fork for suspending a front wheel of a two-wheeled vehicle.

(Prior Art) Usually, a front fork that suspends the front wheel of a two-wheeled vehicle includes a pair of outer pipes and a pair of inner pipes that are slidably inserted into each of the outer pipes via a spring. The outer circumferential surface is in sliding contact with the inner circumferential surface of the outer pipe via a slide bush. Hydraulic oil is sealed inside these to dampen the sliding movement of the inner pipe.

This type of front fork has two types: an upright type in which the inner pipe is attached to the vehicle body and the outer pipe to the front wheel axle, and an inverted type in which the outer pipe is attached to the vehicle body and the inner pipe to the front wheel axle. However, in recent years, inverted front forks have come into widespread use due to their advantages over the royal type in terms of improved front fork rigidity and weight reduction.

In such an inverted front fork, the inside of the inner pipe is usually separated into an upper oil chamber and a lower oil chamber by a sliding member provided in the outer pipe so as to be able to slide freely along the inner circumferential surface of the inner pipe. The hydraulic oil is sealed in. These oil chambers communicate with each other via an orifice, and as the inner pipe slides relative to the outer pipe and the sliding member, hydraulic oil flows between the two oil chambers. At this time, since the hydraulic oil flows through the orifice, flow resistance is generated, thereby damping the sliding movement of the inner pipe.

In addition, in order to reduce the weight of such an inverted front fork as much as possible, the inner pipe is usually hollow from its upper end to its lower end, so hydraulic oil flows from the lower end of the inner pipe. Enclosed up to near the top.

However, especially in an inverted front fork where the sliding stroke of the inner pipe is relatively small, a relatively small amount of hydraulic oil is required to dampen the sliding movement of the inner pipe, and therefore, the amount of hydraulic oil that is sealed in the lower part of the inner pipe is sufficient. In many cases, the hydraulic fluid used is unnecessary. In such a case, the weight of the front fork increases due to the unnecessary amount of hydraulic oil, which hinders weight reduction.

Furthermore, in order to further improve the running performance of two-wheeled vehicles, it has been desired to further improve the damping force that dampens the sliding motion of the inner pipe.

(Problem to be Solved) The present invention solves this problem and reduces unnecessary amount of hydraulic oil in an inverted front fork in which hydraulic oil is sealed in the inner pipe to damp the sliding movement of the inner pipe. It is an object of the present invention to provide an inverted front fork which can be reduced in weight and further improve the damping force for damping the sliding movement of the inner pipe.

(Means for Solving the Problems) In order to achieve the above object, the inverted front fork of the present invention has an inner pipe slidably inserted into an outer pipe, and the end protruding from inside the outer pipe is attached to a front wheel of a two-wheeled vehicle. In an inverted front fork, the outer pipe is connected to the axle of the two-wheeled vehicle, the outer pipe is attached to the vehicle body side of the two-wheeled vehicle, and the inner pipe is sealed with hydraulic oil for damping the sliding movement of the inner pipe. A partition wall separating the interior into an air chamber on the end side connected to the axle and an oil chamber on the outer pipe side is provided inside the inner pipe, and the hydraulic oil is sealed in the core oil chamber. Features.

Further, the partition wall is provided so as to be slidable along the inner circumferential surface of the inner pipe.

(Function) According to this means, the inside of the inner pipe is separated into the oil chamber and the air chamber by the partition wall, the hydraulic oil is sealed in the oil chamber in the inner pipe, and the air chamber becomes a void. Therefore, it is possible to reduce the amount of hydraulic oil sealed in the inner pipe.

When the partition wall is slidably provided along the inner circumferential surface of the inner pipe, the partition wall slides relative to the inner pipe when the inner pipe slides, causing the internal pressure of the air chamber to increase. changes, it becomes possible to attenuate the sliding movement of the inner pipe by the restoring force of the internal pressure.

(Example) An example of an inverted front fork of the present invention will be described with reference to FIGS. 1 to 3. Figure 1 is a side view of the front part of a motorcycle equipped with an inverted front fork, Figures 2 and 3 are
The figures are explanatory sectional views of the upper and lower parts of the inverted front fork, respectively.

In Figs. 1 to 3, 1 is an outer pipe of an inverted front fork A that suspends a front wheel 2 of a motorcycle on a body frame 3, and 4 is an inner pipe whose upper part is inserted into the outer pipe 1 so that it can freely slide. It's a pipe.

As shown in the first figure, the outer pipe 1 is attached to a head pipe 3a at the front end of the vehicle body frame 3 via a top bridge 5a and a bottom bridge 5b, which are fixed to the upper end and the middle part with bolts 6a and 6b, respectively.
It is rotatable together with the handle 7 around the axis of the head pipe 3a.

As shown in the first figure, the inner pipe 4 is connected to the axle 2a of the front wheel 2 via an axle holder 8 fitted to the lower end projecting downward from inside the outer pipe 1, and as shown in the second figure. The upper end thereof is connected to the upper end of the outer pipe 1 within the outer pipe 1 via a spring 9 and is biased downward. As shown in the second figure, the inner pipe 4 is connected to the outer pipe via a slide bush 10a provided on the outer peripheral surface of the tip thereof and a slide bush 10b provided on the inner peripheral surface of the lower end of the outer pipe 1. It is in sliding contact with the inner circumferential surface of 1 and is slidable.

As shown in FIGS. 2 and 3, this inner pipe 4 is hollow over its entire length, and its lower end is closed by an axle holder 8 fitted into the lower end. A partition wall 12 fixed to the inner circumferential surface of the inner pipe 4 via a snap ring 11 is provided at the lower part of the inner pipe 4 protruding from the inside of the outer pipe 1, as shown in the third figure. is separated by the partition wall 12 into an upper oil chamber 4a and a lower air chamber 4b. The core oil chamber 4a is filled with hydraulic oil for damping the sliding motion of the inner pipe 4, and the air chamber 4b is a closed gap.

Furthermore, a hydraulic braking mechanism 13 for damping the sliding movement of the inner pipe 4 is provided within the outer pipe 1 as shown in the second diagram. This hydraulic braking mechanism 13 is the outer pipe 1
The piston 14 is provided with a piston 14 extending downward from the upper end, and the piston 14 is inserted into the interior of the inner pipe 4 from its tip, so that the sliding member 15 at its tip is in contact with the oil chamber 4a.
The oil chamber 4a is slidably contacted with the inner circumferential surface of the inner pipe 4, and the oil chamber 4a is separated into a first oil chamber 4a+ and a second oil chamber 4az by the sliding member 15. The first oil chamber 4a+ and the second oil chamber 4az communicate with each other via communication holes 15a, 15b provided in the sliding member 15 and an orifice 16 provided in the piston 14.

As the inner pipe 4 slides within the outer pipe, the sliding member 15 of the hydraulic braking mechanism 13 moves in the opposite direction to the oil chamber of the inner pipe 4 relative to the inner pipe 4. Slide inside 4a.

Therefore, the hydraulic oil sealed in the oil chamber 4a is
The communication hole 15a between the oil chamber 4a and the second oil chamber daz,
15b and the orifice 16, but when the hydraulic oil flows through these communication holes 15a, 15b and the orifice 16, flow resistance occurs, thereby damping the sliding movement of the inner pipe 4.

Note that the partition wall 12 has the sliding member 15 as described above.

It is provided as close to the upper side of the inner pipe 4 as possible at a position where it does not come into contact with the sliding member 15 during sliding.

In the front fork A having such a configuration, as described above, the partition wall 12 is provided in the inner pipe 4, hydraulic oil is sealed in the oil chamber 4a above the partition wall 12, and the air chamber 4b below is used as a void. Since the partition wall 12 is provided as close to the upper side of the inner pipe 4 as possible to make the oil chamber 4a small, the amount of hydraulic oil sealed in the oil chamber 4a is the minimum amount necessary, and the front Fork A is lightweight.

Next, another example of the inverted front fork of the present invention will be described in the fourth example.
This will be explained according to the diagram. FIG. 4 is an explanatory sectional view of the lower part of this inverted type front fork.

In this front fork, the partition wall 12 of the front fork A is not fixed to the inner circumferential surface of the inner pipe 4, but is slidable along the inner circumferential surface.

The air chamber 4b on the lower side of the partition wall 12 is pressurized and balanced with the weight of the hydraulic oil sealed in the upper oil chamber 4a.

Similar to the sliding member 15, this partition wall 12 slides relative to the inner pipe 4 in a direction opposite to the sliding direction as the inner pipe 4 slides. At this time, since the internal pressure of the air chamber 4b changes, a restoring force acts to return the internal pressure to its original state, and this restoring force is caused by the sliding of the inner pipe 4, similar to the operation of the hydraulic braking mechanism 13. It acts to attenuate the

Therefore, this front fork has a higher damping force for damping the sliding movement of the inner pipe 4 than the front fork A. And, like front fork A,
Since the air chamber 4b on the lower side of the partition wall 12 is a void,
Of course, it is lightweight.

(Effects) As is clear from the above description, according to the inverted front fork of the present invention, a partition wall is provided in the inner pipe to separate the interior of the inner pipe into an oil chamber and an air chamber, and hydraulic oil is stored in the core oil chamber. By enclosing it, the unnecessary amount of hydraulic oil can be reduced, and the air chamber becomes a void,
The weight of the inverted front fork can be reduced.

In addition, when the partition wall is provided to be slidable along the inner circumferential surface of the inner pipe, the restoring force of the internal pressure caused by the change in the internal pressure of the air chamber when the inner pipe slides is applied to the inner pipe. By acting as a damping force for damping the motion, the damping force can be improved, and a front fork that is lightweight and has excellent operability can be provided.

[Brief explanation of the drawing]

FIG. 1 is a side view of the front part of a motorcycle equipped with an example of an inverted front fork of the present invention, FIGS. 2 and 3 are explanatory sectional views of the upper and lower parts of the front fork, respectively, and FIG. FIG. 2 is an explanatory cross-sectional view of the lower part of another example of the inverted front fork of the present invention. A...Inverted front door...Outer pipe 2a...Axle 4...Inner pipe 4b...Air chamber Fork 2...Front wheel 3...Vehicle frame 4a...Oil chamber 12... Bulkhead and 1 other person FIG, 1 4-' FIG, 3

Claims (1)

[Scope of Claims] 1. The end of the inner pipe slidably inserted into the outer pipe and protruding from inside the outer pipe is connected to the axle of the front wheel of the two-wheeled vehicle, and the outer pipe is attached to the vehicle body side of the two-wheeled vehicle. , in an inverted front fork in which hydraulic oil for damping sliding of the inner pipe is sealed in the inner pipe, the inside of the inner pipe is connected to an air chamber on an end side connected to the axle; 1. An inverted front fork, characterized in that a partition wall separating the inner pipe from an oil chamber on the outer pipe side is provided inside the inner pipe, and the hydraulic oil is sealed in the oil chamber. 2. The inverted front fork according to claim 1, wherein the partition wall is slidably provided along the inner peripheral surface of the inner pipe.