JPS604032B2 - Front forks of motorcycles, etc. - Google Patents

Description

[Detailed Description of the Invention] When a two-wheeled vehicle, etc. is running at high speed and suddenly brakes, an extremely large load is applied to the handlebars due to the inertia of the rider, which causes the handlebars to sink significantly, impairing controllability, which is dangerous. It is.

In order to eliminate this phenomenon, a valve chamber linked to the brake was conventionally formed on the side of the bottom case, but this had the disadvantage of making the foundation of the fork extremely complicated. The present invention eliminates this drawback and provides a front fork whose characteristics can be easily adjusted. FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, in which a bottom case 1 has a fork pipe 2.
The lower parts of the fork vip 2 are slidably fitted together, oil 3 is filled inside them, and the piston 5 at the upper end of the sheet pipe 4 shielded at the bottom of the bottom case 1 is slidably fitted inside the fork vip 2. A vehicle body suspension spring 6 is stretched between the piston 5 and the upper part of the pipe 2.

In addition, an oil seal 7 is provided at the upper end of the bottom case 1.
A check valve 8 is formed at the lower end of the fork pipe 2, which opens when the pipe descends and closes when it rises, and an orifice 9 and a relatively large oil hole 10 are provided at the upper and lower parts of the seat pipe 4, respectively. . Further, an operating punch 11 is arranged inside the seat pipe 4, and a valve 12 is attached to the upper end of the operating punch 11.
is provided opposite to the oil hole 13 of the piston, and a spring 14 is suspended between the valve 12 and the piston 5. The lower end of this operation village 11 is pulled out to the outside via the O-ring 15, and the movable cable 16
It is connected to. Further, a cylindrical auxiliary oil chamber 17 is connected to the lower part of the bottom case 1, a free piston 19 having an O-ring 18 is fitted into the oil chamber, and a high-pressure gas 20 is sealed behind it, and this high-pressure gas is A stopper 21 is provided which keeps the free piston 19 under constant pressure. The high-pressure gas chamber further includes a piston 2 having an O-ring 22.
3, and this piston is brought into contact with the adjusting screw 24. The bottom case 1 of the above-mentioned front fork is connected to the shaft of the front wheel, the front part of the vehicle body is suspended on the fork pipe 2, and the flexible cable 16 is connected to the brake lever, and the valve 12 is always connected. It's open.

When a motorcycle or the like travels in this state and the fork pipe 2 descends due to the impact received from the road surface, the check valve 8 opens, and the oil at the bottom of this valve easily flows into the top, and the oil at the bottom of the pipe 2 becomes oily. The pipe 2 easily descends, with only a relatively small damping force being generated as it flows through the holes 10 and 13 to the top of the piston. Next, when the pipe 2 attempts to rise due to the force of the spring 6, the check valve 8 closes, and the oil above it flows through the orifice 9, generating a large damping force.
In the parenthesized state, the free piston 19 is in pressure contact with the stopper 21, and no pressure is applied to the oil 3 or the air on the oil surface. Therefore, the relationship between the downward distance L of the fork pipe 2 and the reaction force P of the suspension spring 6 It is determined only by the characteristics, and is expressed as, for example, curve A in FIG. However, when the brake is applied, the control panel 11 is connected via the movable cable 16.
is driven upward, the valve 12 comes into pressure contact with the lower surface of the piston 5 and the oil hole 13 is closed.

Therefore, when a large load is applied to the fork pipe 2 due to the inertia of the passenger and it tries to descend, the oil pressure at the lower part of the piston 5 increases, and the free piston 19 moves up by the oil pressure, compressing the high-pressure gas 20. That is, assuming that the pressure of the gas 20 is P, the relationship between the downward distance L of the fork pipe 2 and the reaction force P is expressed as, for example, a curve B by the sum of the air spring caused by the gas 201 and the suspension spring 6. As described above, in the front fork of the present invention, when the brake is applied, the reaction force applied to the fork pipe increases rapidly, and its compression is prevented. This prevents the steering wheel from sinking when the brakes are suddenly applied while driving at high speeds, thereby maintaining stability in steering. If the pipe 2 receives a stronger impact from the road surface in the braced state, the pipe 2 descends along the curve B, so that the impact can be alleviated.
Also, adjust the screw 24 to adjust the pressure of the high pressure gas 20 to p2, p.
If it is set to 3, the characteristics will be as shown by curves C and D, so the desired characteristics can be easily obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a characteristic curve of the front fork of the present invention. In the figure, 1 is the bottom case, 2 is the fork pipe, 3 is the oil, 4 is the seat pipe, 5 is the piston, 8 is the check valve, 11 is the operation port, 12 is the valve, 13 is the oil hole, and 16 is the oil hole. 17 is an auxiliary oil chamber, 19 is a free piston, and 2 rivers are high pressure gas. Next/Dokuji Z Captive

Claims (1)

[Claims] 1. The lower part of the fork pipe is slidably fitted into the bottom case, the inside of the fork pipe is filled with oil, and the piston formed at the upper end of the sheet pipe installed in the bottom of the bottom case is inserted inside the fork pipe. Slidably fit together.
An operating lever that interlocks with a brake lever of a motorcycle or the like is disposed in the seat pipe, and a valve formed at the tip of the operating lever is provided opposite to the oil hole so that the oil hole of the piston closes when the brake is applied. At the same time, a free piston is fitted into an auxiliary oil chamber connected to the lower part of the bottom case, and high pressure gas is sealed behind the free piston so that the pressure can be adjusted;
A front fork for a two-wheeled vehicle, etc., further comprising a stopper which the free piston comes into contact with under pressure of high-pressure gas.