JPS6243911Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a front fork for hydraulic shock absorbing, such as used in a motorcycle.

While conventional front forks absorb strong shocks and vibrations, they are not able to adequately handle small shocks and vibrations.

Therefore, this invention provides a hydraulic shock absorbing front fork that, in addition to its normal shock absorbing function, also absorbs small vibrations from the road surface, providing a comfortable shock absorbing function at all times.

An embodiment of this invention will be described below based on the drawings. The drawing shows a front fork used in a motorcycle, and as shown in FIG. 1, the upper end of the fork pipe 1 is closed by a fork bolt 2, and the lower part is slidably inserted into and supported by a bottom case 3. The fork bolts 2 and the bottom case 3 are connected between the members of the vehicle body that are to be buffered to provide a well-known buffering function. oil and air 5, a free piston 6 that partitions these, upper and lower springs 7 and 8 that hold the free piston 6 at a neutral position between the oil chamber 12 side and the air chamber 11 side from above and below, and the free piston 6. A communication pipe 16 for communicating the oil chamber 12 side and introducing compressed air from the valve 14 is built-in.

The above-mentioned free piston 6 is formed into a hollow disk shape, and has O-rings 17,
18 is provided around the circumference and is fitted into the fork pipe 1 with a communication pipe (described later) inserted therethrough. As a result, an air chamber 11 is formed above the free piston 6, and an oil chamber 12 is formed below the free piston 6, which are airtightly separated from each other.

An upper spring 7 is fitted inside the air chamber 11 side, and a lower spring 8 is fitted inside the oil chamber 12 side, so that the free piston 6 is elastically supported in the axial direction of the inner hole 10. While resting on the upper surface of the spring 8, the upper spring 7 is in a free state.

The above-mentioned communication pipe 16 is installed vertically at the center of the lower surface of the fork bolt 2, and when attached to the fork pipe 1, its lower end opening 24 extends toward the oil chamber 12 that extends vertically through the free piston 6. As a result, the free piston 6 is airtightly fitted into the communication pipe 16 and is in a state where it can freely slide in the axial direction.
Further, the piston receiver 19 is prevented from being removed from the communication tube 16 by a flange-shaped piston receiver 19 formed around the lower end of the communication tube 16 and an O-ring 20 provided on the upper surface thereof. Therefore, the free piston 6 moves up and down within the vertical length of the communication pipe 16, and the length is such that when the free piston 6 moves upward, a sufficient air compression effect can be obtained in the air chamber 11. Set to .

The internal passage 21 of the communication pipe 16 is connected to the oil chamber 1.
The lower end opening 24 facing the second side is provided in communication with a compressed air introduction valve 14 attached to the fork bolt 2 above the lower end opening 24. On the other hand, the air valve 22 attached to the fork bolt 2 and the sub-tank 15 provided outside are connected by a communication pipe 23 made of an elastic material such as rubber.
5 and the air chamber 11 are communicated with each other. Although the sub-tank 15 is fixed to other external members by appropriate fixing means, the sub-tank may be provided integrally with the fork pipe. Also, the valve 14 in the oil chamber 12
Cavitation of the oil in the oil chamber 12 can be prevented by appropriately adjusting the pressure of the compressed air introduced through the oil chamber 12. Reference numeral 13 denotes a spring receiver, which locks the upper end surface of the upper spring 7 during buffering. 25 is a plug for adjusting compressed air in the sub tank 15. Note that in place of the upper spring 7, another elastic body such as a stopper rubber made of rubber or resin may be used.

The front fork constructed in this way has a damping mechanism (not shown) based on the well-known damping effect of buffer oil through the connection between the fork pipe 1 and the bottom case 3, in order to cope with shocks stronger than those on normal road surfaces. The free piston 6 also absorbs small shocks and vibrations. That is, in response to a small impact, the free piston 6 pushes up the oil 4 inside and moves upward to compress the air in the air chamber 11. At that time, air chamber 1
The air in the tank 1 passes through the communication pipe 23 and is simultaneously compressed in the sub tank 15. Based on these two air compression actions, slight shocks, slight vibrations, etc. are reliably absorbed by the air reaction force, and the riding comfort of the vehicle body etc. is reliably improved. Further, at this time, since the free piston 6 moves upward while being elastically buffered by the upper spring 7, no sudden internal impact is exerted on the fork bolt 2 or the like located above.
Further, when the free piston 6 descends, it is elastically received by an O-ring 20 for receiving the piston.

In this way, it is configured to utilize the air reaction force in the air chamber inside the fork pipe and the sub-tank as a buffer against small shocks, etc., so any vibration can be absorbed. Cavitation can also be prevented by adjusting the compressed air pressure, resulting in a front fork with extremely high buffering capacity.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention, and FIG. 1 is a longitudinal sectional front view of the main part showing a front fork for hydraulic shock absorbing. 1...Fork pipe, 3...Bottom case,
4...oil, 5...air, 6...free piston,
7... Upper spring, 8... Lower spring, 11
...Air chamber, 12...Oil chamber, 15...Sub tank, 16...Communication pipe.

Claims (1)

[Scope of utility model registration request] In a front fork for hydraulic shock absorbing, in which a fork pipe containing oil and air for shock absorption is slidably supported by a bottom case, there is a free spacer that partitions the fork pipe into an oil chamber side and an air chamber side in the axial direction thereof. A piston is provided, the free piston is slidable in the axial direction and held at a neutral position within the fork pipe by an elastic body, and a communication pipe communicating with the oil chamber side via the free piston is provided within the fork pipe. A front fork for hydraulic shock absorption that is installed vertically and connects the sub-tank and air chamber installed on the outside with a communicating pipe.