JPS58145585A - Front fork for car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a front fork for a vehicle that suspends a vehicle body and an axle.

The inner cylinder and the outer cylinder are slidably fitted, the diameter-enlarged tip of the sheet pipe planted in the inner bottom of the outer cylinder slides into contact with the inner cylinder, and the inner cylinder tip is equipped with a damping force generation mechanism. In a front fork for a vehicle, high airtightness is required between each sliding member in order to obtain a stable damping force, and therefore the sliding resistance generated between the inner cylinder and the outer cylinder becomes large.

Therefore, if the front fork is adjusted to provide effective damping force when the wheels receive a large impact, the front fork's damping will not be able to sufficiently absorb a small impact, and the impact will be transmitted to the vehicle body. There is a problem that ride comfort deteriorates.

In view of the above problems with this type of front fork, the inventor has
The present invention has been developed to effectively solve this problem, and its purpose is to fit a sliding pipe that slidably fits on the outer periphery of the inner cylinder between the upper bracket and the under bracket on the vehicle body side. By closing the upper end of the sliding pipe with a cap and by stretching a coil spring between the cap and the 7-octane bolt of the inner cylinder, small shocks are absorbed and alleviated by the expansion and contraction of the coil spring. To provide a front fork for a vehicle in which direction 1 of riding comfort is not shown.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional side view of a front fork 1 according to the present invention, in which an inner cylinder 3 is fitted into an outer cylinder 2 from above, and a seat pipe 4 is planted in the inner bottom of the outer cylinder 2. is,
The enlarged diameter end portion 4a of the seat pipe 4 is in sliding contact with the inner peripheral portion of the inner tube 3 as shown in the figure.

A guide bush 5 and an oil 7-lue 6 that slide on the outer periphery of the inner cylinder 6 are fitted into the inner periphery of the upper end of the outer cylinder 2, and the open upper end of the outer cylinder 2 is closed with a dust seal 7. On the other hand, an axle mounting bracket 8 is screwed onto the lower end of the outer cylinder 2.

Further, a fork bolt 9 is screwed onto the upper end of the inner cylinder 3,
On the other hand, a free valve 10 is provided in the lower part of the interior of the valve 3 so as to be in sliding contact with the outer periphery of the seat pipe 4.

Further, a plurality of orifices 11, 12, etc. are bored in the upper and lower outer peripheries of the sheet pipe 4, respectively.
A coil spring 13 is stretched inside the inner cylinder 6 and between the upper end of the seat pipe 4 and the fork bolt 9. In addition, 14 in the drawing is a rebound spring.

In this way, hydraulic oil and gas are sealed inside the inner and outer cylinders 3 and 2, and the hydraulic oil flows as the inner and outer cylinders 6.2 move relative to each other, and the pulp of this hydraulic oil flows. 10, the required damping force is obtained by the flow loss when passing through the orifices 11, 12, . . . .

On the other hand, a ring-shaped sliding member 16.16 slides from above on the outer periphery of the inner cylinder 6, and the S-ib 15 is fitted on the upper and lower sides of the inner periphery.
It is fitted so that it can freely slide up and down. The upper end of this sliding pipe 15 is closed with a cap 17, the lower end opening of this 15 is closed with a dust seal 18, and upper and lower parts of the outer periphery of this 15 are attached with upper and lower parts that are attachment members to the vehicle body.
A bracket 19 and an under bracket 20 are fitted respectively.

As shown in the figure, a coil screw 21 is stretched between the cap 17 and the fork gel 9 in the sliding pipe 15, and a rod 22 is suspended from the center lower part of the cap 17 with its upper end screwed. .

The rod 22 slidably passes through the fork bolt 9, and a stopper 23 is fastened to the lower end of the rod with a nut 24. A rebound spring 25 is interposed between the stopper 23 and the fork bolt 9. There is. A rebound rubber 26 is provided on the lower surface of the cap 17 and on the outer periphery of the rod 22. It is assumed that the spring constant of the coil spring 21 is smaller than that of the coil spring 13, so that it is easier to bend and deform under the same load.

The sliding pipe 15 is connected to the vehicle body through the upper bracket 19 and the under bracket 20 provided on the outer periphery of the sliding pipe 15, and the lower end of the outer tube 2 is connected to the axle by the mounting bracket 8. .

Next, the operation of the front fork 1 explained above will be described.

First, to explain the compression stroke, as mentioned above, the spring constant of the coil spring 21 is smaller than that of the coil spring 16, and the coil spring 21 is more easily deflected. Only the sliding pipe 15 moves downward relative to the inner and outer cylinders 3.2, so that small external shocks are effectively absorbed and alleviated by the deflection of the coil spring 21, improving riding comfort. Improvements will be made.

Thereafter, when the amount of compression deformation of the coil spring 21 increases and the reaction force of the spring 210 increases beyond the force necessary to compress the coil spring 13, the inner cylinder 6 starts to invade the outer cylinder 2,
As the inner cylinder 3 enters, the internal hydraulic oil flows, and as described above, the required damping force is generated due to the flow loss of the hydraulic oil. As a result, even large impacts are effectively absorbed and alleviated, and propagation of the impact toward the vehicle body is effectively blocked, improving ride comfort.

Next, when the front fork 1 moves to an extension stroke, the sliding pipe 15 first moves upward due to the reaction force of the coil spring 21, and then the inner cylinder 6 moves upward with respect to the outer cylinder 2 without being attenuated.

Therefore, small impacts are effectively absorbed and alleviated by the elongation and deformation of the coil spring 21 within the sliding tube 15.

In this way, even when the front fork 1 is adjusted to obtain an effective damping force when the wheel receives a large impact, small impacts can be effectively absorbed and alleviated by the expansion and contraction of the coil spring 21 as the sliding pipe 15 expands and contracts. Therefore, the riding comfort can be further improved.

Next, modified embodiments of the present invention are shown in FIGS. 2 and 3, respectively.

The example shown in FIG. 2 connects the sliding pipe 115 and the outer cylinder 102 with a dust boot 130 to protect the sliding surface of the inner cylinder 103, and the example shown in FIG. is positioned on the upper surface of the fork bolt 209, the sliding member 215 is attached to the outer circumferential side of the inner cylinder 203, and the rebound spring 225 is attached to the sliding pipe 21.
5 and the inner cylinder 203, it is clear that the above effects can also be achieved in these embodiments.

As is clear from the above description, according to the present invention, a sliding pipe that is slidably fitted to the outer periphery of the inner cylinder is fitted between an upper bracket and an under bracket on the vehicle body side, and the upper end of the sliding pipe is connected to a cap. In addition, since a coil spring is stretched between the cap and the fork bolt of the inner cylinder, small shocks can be effectively absorbed and alleviated by the expansion and contraction of the coil spring, further improving riding comfort. can.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a longitudinal sectional side view of a front fork according to the present invention, and FIGS. 2 and 3 are broken side views of main parts of the front fork according to modified embodiments of the present invention. It is a diagram. In the drawing, 2 is an outer cylinder, 6 is an inner cylinder, 9 is a fork bolt, 1
6.21 is a coil spring, 15 is a sliding pipe, 17 is a cap, 19 is an upper bracket, and 20 is an under bracket. Patent applicant Showa Seisakusho Co., Ltd. Agent Patent attorney Yo Shimoda Patent attorney Kunihiko Ohashi

Claims (1)

[Claims] In a vehicle front fork where an inner cylinder and an outer cylinder are slidably fitted to suspend the vehicle body and the axle, a sliding pipe that is slidably fitted to the outer periphery of the inner cylinder is connected between the upper bracket and the under bracket on the car body side. A front fork for a vehicle, characterized in that the upper end of the sliding pipe is closed with a cap, and a coil spring is stretched between the cap and the fork bolt of the inner cylinder.