JPS6346000B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a front fork of a motorcycle, etc.
Specifically, one side of the gas chamber divided by the free piston is communicated with the inside of the front fork, and the other side is connected via a switching valve that is linked to the sinking of the car body and an on-off valve that is linked to the operation of the brakes. This invention relates to a front fork connected to a high-pressure gas supply device.

Conventionally, a separate gas chamber was provided that communicated with the gas chamber inside the front fork via a communication path, and a switching valve that was linked to the brake lever was installed in the middle of the communication path, and the communication path was closed when the brake was applied. A so-called anti-nob-dive type front fork that prevents sinking when driving is known. However, the conventional structure is such that the gas spring characteristics are changed simply by changing the volume of the entire gas chamber.
The anti-nob-dive function did not work well, and the gas spring characteristics could only be controlled in two stages.

The present invention is designed to prevent the vehicle body from sinking by supplying high-pressure gas to the gas chamber leading to the inside of the front forks to increase the gas pressure inside the front forks when the vehicle body sinks by more than a certain amount due to braking. In particular, it is possible to widen the selection range of spring characteristics by changing the pressure of high-pressure gas, and at the same time, by changing the spring characteristics according to the amount of sinking of the car body, when the amount of sinking is large, the "hard cushion" will sink again. It provides a front fork that acts as a "soft cushion" when the volume is small.

Hereinafter, one embodiment of the present invention will be described based on the drawings. In FIG. 1, reference numeral 1 denotes a front fork in which a piston 3 is slidably fitted into a fork pipe 2 via a coil spring 4, and oil and compressible gas are sealed inside. The front part of a vehicle body such as a two-wheeled vehicle is suspended on the upper part of the piston rod 6, and the lower part of a bottom case 7 fixed to the lower end of the piston rod 6 is connected and supported to the front wheel axle side.

Reference numeral 8 denotes a gas chamber whose interior is divided into two chambers 10 and 11 by a free piston 9 fitted in a slidable manner; in the embodiment shown in FIG.
is built into fork pipe 2. Gas chamber 8
One chamber 10 communicates with the interior 2' of the fork pipe 2, and the other chamber 11 communicates with the air passage 1.
2. The ventilation passage 12 is linked to the sinking displacement of the vehicle body.
The switching valve 14 and the switching valve 13 are connected to the high-pressure gas supply device 15 through the switching valve 13 that opens and closes, and the switching valve 14 that opens and closes the ventilation passage 12' from the switching valve 13 in conjunction with the operation of the brake.
When the chamber 10 is opened, high-pressure gas flows into the chamber 11 and pushes the free piston of the gas chamber 8, thereby increasing the gas pressure inside the chamber 10 and the front fork leading thereto.

The switching valve 13 has a plunger 17 slidably fitted in a valve case 16 extending in the vertical direction.
Rod 1 integrally formed below plunger 17
8 is made to protrude to the lower outside of the valve case 16. The valve case 16 communicates with the ventilation path 12 to the gas chamber 8 and the ventilation path 12' to the on-off valve 14 through through holes 19, 19, and above these through holes 19, there is a ventilation path 12 connected to the ventilation path 12. A communicating exhaust path 20 and an exhaust port 21 to the outside are provided. The valve case side of the switching valve 13 configured as described above is connected to the vehicle body side, and the plunger rod 18 is connected to the wheel axle side, so that the plunger 17 and the valve case are connected by vertical positional fluctuation between the vehicle body and the axle. 16, and plunger 1
7, the passage hole 19 of the valve case 16 and the exhaust passage 20 are configured to be opened and closed alternately at certain times and closed simultaneously at other times.

The structure of the switching valve 13 is not limited to the embodiment shown in the figure.
Any other structure may be used as long as it opens and closes the exhaust passage 20. For example, the exhaust path 2 of the valve case 16
0 and the exhaust port 21 are provided below the through hole 19, and the plunger rod 18 is made to protrude to the outside above the valve case 16, and the plunger rod 18 is connected to the vehicle body side, and the valve case 16 is connected to the wheel axle side. It can also be a structure.

The on-off valve 14 is provided in the middle of a ventilation path 12' that communicates the switching valve 13 and the high-pressure gas supply device 15, and a rod 23 protruding outward from the on-off valve case 22 is remotely operated in conjunction with the operation of the brake. By reciprocating the rod 23, the valve member 24 fixed to the rod 23 opens and closes the internal passage 25 of the on-off valve case 22. That is, the valve member 24 is in the closed position due to the spring 26 when the brake is not activated.
When the rod 23 is pulled against the spring in conjunction with brake operation, the valve seat 24 ascends and opens the passage 25.

As for means for interlocking the opening/closing valve 14 and brake operation, there is a method in which the rod 23 connected to the valve member 24 is interlocked with a brake lever (not shown) via a brake wire, a hydraulic circuit, etc., or a reciprocating movement of the rod. An appropriate method can be used, such as a method in which the torque is linked to the torque during braking. Further, the on-off valve 14 may be a solenoid valve synchronized with the brake lever.

The high-pressure gas supply device 15 that communicates with the on-off valve 14 is illustrated as having a configuration in which a compressor 27 and a tank 28 for storing the high-pressure gas pressurized by the compressor are connected in series, but the tank 28 is omitted and the compressor 27 is connected. 27 may be directly connected to the on-off valve 14 via the air passage 12'.

FIG. 2 shows another embodiment of the present invention.
In the embodiment shown in the figure, the gas chamber 8 is built into the fork pipe 2, whereas in the example shown in FIG. It communicates with the inside of the fork pipe 2' through the fork pipe. In addition, from the chamber 11 of the gas chamber 8 to the ventilation path 12, the switching valve 13,
As for the circuit leading to the high pressure gas supply device 15 via the on-off valve 14, the configuration shown in FIG. 1 is applied as is.

Next, the front fork sinking prevention operation according to the present invention will be explained in relation to vehicle height fluctuation and brake operation.

When the brake is not applied, the on-off valve 14
The valve member 24 is pressed against the stepped valve seat of the internal passage 25 by the spring 26 to close the passage 25, and since the vehicle body does not sink, the switching valve 13
The plunger 17 closes the through hole 19 and opens the exhaust passage 20 and the exhaust port 21. Therefore, in this state, the free piston 9 of the gas chamber 8 is pressed toward the chamber 11 by the compressible fluid pressure inside the front fork 2', and the capacity of the chamber 10 of the gas chamber 8 is at its maximum. Therefore, the cushion spring characteristics of the front fork are in the softest state.

Now, when the brakes are applied to the vehicle body, the valve member 24 of the on-off valve 14 is pulled up from the valve seat against the spring 26, and the internal passage of the on-off valve 14 opens.
High pressure gas from 5 is sent to switching valve 13.
However, when the brakes are weak and the amount of depression of the vehicle body does not exceed a certain amount, the switching valve's passage 19 is closed, so the cushion spring characteristics are relatively soft.

When the vehicle body sinks by more than a certain amount due to the reaction of braking, the passage 19 of the switching valve 13 opens and the exhaust passage 20 is closed, so high-pressure gas flows into the chamber 11 of the gas chamber 8 and moves the free piston 9 to the chamber 10 side. Press down on chamber 1 of gas chamber 8.
Lower the capacity of 0. As a result, the front fork's cushion spring characteristics increase, creating a force that lifts the sunken car body. When the vehicle body is lifted to a certain point, the through hole 19 of the switching valve 13
is closed by the plunger 17, and when the vehicle body is lifted a little further, the exhaust passage 20 of the switching valve 13 and the exhaust port 21 are communicated, and a portion of the high-pressure gas is released from the exhaust port 20, so that the cushion is slightly lowered.
Eventually, the plunger 17
It becomes stable when both the exhaust passage 20 and the exhaust passage 20 are closed.
When the brake is released, the vehicle body rises to its original height, so the exhaust passage 20 and exhaust port 21 of the switching valve 13 are completely opened, the high pressure gas that had previously entered the chamber 11 is released, and the free piston 9 is moved to the front fork. It is pushed toward the chamber 11 by the compressed fluid pressure and returns to its original state.

The front fork of the present invention operates as described above, but since the time it takes for the plunger 17 to return varies depending on the amount of depression of the vehicle body,
Correspondingly, the amount of high-pressure gas sent into the gas chamber 8 changes. Therefore, if the amount of sinking is large, it will take time to recover, and the amount of high-pressure gas sent to the gas chamber 8 will increase accordingly, and the gas pressure of the front fork will be adjusted to a higher level, causing the front fork to work as a stiff cushion. On the other hand, if the amount of sinking is small, a soft cushion will work.

The high-pressure gas from the exhaust port 21 of the switching valve 13 may be discharged into the atmosphere, but it may also be returned to the compressor 27 via a pipe or the like.

As described above, the present invention supplies high-pressure gas to one side chamber of the gas chamber communicating with the front forks in conjunction with the brake operation, thereby improving the function of preventing sinking during braking, and by adjusting the gas pressure. In addition to significantly expanding the selection range of spring characteristics against sinking during braking, it is also equipped with a switching valve that operates depending on the amount of sinking of the vehicle body, so when the amount of sinking is large, the so-called hard cushion can be used again. When the amount of sinking is small, the soft cushion works, improving riding comfort and preventing accidents.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing one embodiment of a front fork according to the present invention, and FIG. 2 is a partial sectional view showing another embodiment. 1...Front fork body, 2...Fork pipe, 8...Gas chamber, 9...Free piston, 12,1
2'...Vent passage, 13...Switching valve, 14...Opening/closing valve,
15... High pressure gas supply device, 17... Plunger,
20...Exhaust path, 21...Exhaust port, 24...Valve member.

Claims (1)

[Claims] 1. In a front fork of a two-wheeled vehicle in which a piston is slidably fitted into a fork pipe and oil and compressible gas are sealed inside, the fork pipe 2 of the front fork 1 is partitioned with a free piston 9 inside or outside the fork pipe 2. two chambers 10,
A gas chamber 8 having a gas chamber 11 is provided, and a chamber 1 on one side is provided.
0 to the inside 2' of the fork pipe 2, and the chamber 11 on the other side to the high pressure gas supply device 15 via ventilation passages 12, 12', and between these ventilation passages 12, 12', Exhaust path 2
The plunger rod 18 of the plunger 17 has an exhaust passage consisting of an exhaust port 21 and an exhaust port 21, and alternately opens and closes the exhaust passage and the through holes 19 of the ventilation passages 12 and 12' as the vehicle body and axle are vertically displaced. and a valve case 16, one of which is connected to the axle side and the other to the vehicle body side.
3 is provided, and when the amount of sinking of the vehicle body during braking is less than a certain amount, the plunger 17 closes in the through hole 19.
is kept closed, the passage hole 19 is opened at a certain amount or more, the exhaust passage 20 is closed, and the switching valve 1 is kept closed.
3 and the high-pressure gas supply device 15.
2', a valve member 24 is pulled in conjunction with the operation of the brake to open an internal passage 25 communicating with the ventilation passage, and an on-off valve 14 is connected which sends high-pressure gas from the high-pressure gas supply device 15 to the switching valve 13. A front fork for a two-wheeled vehicle, etc., characterized in that it is configured by: