JPH0331944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seat pipe installation device used, for example, in a front fork used in a motorcycle.

As is well known, a fork pipe having a main piston at its tip is slidably fitted into a bottom case filled with oil, and a sub-piston at the tip of a sheet pipe implanted from the bottom of the bottom case is attached to the fork pipe. A front fork is used which is slidably inserted into the fork and generates a damping force when compressed and when expanded. Conventionally, the seat pipe was installed at the bottom of the bottom case by providing a female thread on the inside of the pipe at the base of the seat pipe and fixing it directly to the bottom of the bottom case from the outside with a bolt via an oil lock piece. .

However, in this configuration where the base of the seat pipe is directly bolted to the bottom case, it is necessary not only to match the center of the bottom case and the center of the seat pipe at the base, but also to match the top end of the seat pipe accurately. . This is because the main piston and valve attached to the tip of the fork pipe, especially the Sachs type valve, slide closely against the inner circumference of the fork pipe and the outer circumference of the seat pipe during compression or expansion, respectively, causing the seat pipe to become biased. If the seat pipe and the valve are mounted in the opposite direction, the sliding movement between the main piston and the valve mechanism will not be smooth, and a gap will be created between the seat pipe and the valve due to wear at the biased portion, and the valve will no longer function as a valve. For this reason, the processing of the seat pipe, especially the precision of the perpendicularity of the end face that contacts the oil lock piece at the base, was particularly important, and precision processing and installation required skill.

The present invention eliminates these conventional drawbacks, and the base of the seat pipe is mounted so as to be slidable in the radial direction, so that some deviation is corrected by displacement of the base of the seat pipe. be. An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the implantation device of the present invention. In the figure, the fork pipe 1 has its upper end closed by a fork bolt (not shown), and its lower part, which has a main piston 1' at its lower end, is slidably inserted into and supported by a bottom case 2, and the fork pipe 1 is a shock absorber for the vehicle body. The fork bolts and the bottom case 2 are connected between the members to provide a well-known buffer function, and the fork pipe 1 has a buffer oil 3 for partitioning it in the sliding direction. A sub-piston 4, an orifice 6' for generating a damping force during the compression process, an orifice 6 and a valve mechanism 5 for generating the damping force during the extension process are provided. The above-mentioned sub-piston 4 is attached to the upper end of a seat pipe 7 installed from the base of the bottom case 2.

The bottom of the bottom case 2 and the seat pipe 7 mentioned above
The base of the seat pipe 7 is bottomed and a hole 7a is provided in the center so that the seat pipe 7 can slide in the radial direction. On the other hand, the bolt 8 is provided with a stepped portion 8a, and when the bolt 8 is fixed to the bottom of the bottom case 2 with the nut 9, the stepped portion 8a is fixed via the oil lock piece 10, and the head of the bolt 8 and the stepped portion 8a are fixed. The seat pipe 7 is made to be able to slide in the radial direction by making the gap slightly larger than the thickness of the bottom of the seat pipe 7.
Of course, the same effect can be obtained by providing the nut 9 with a stepped portion 9a and attaching it with the bolt 8 as shown in FIG.

In this way, even if the axis of the seat pipe 7 does not coincide with the axis of the bottom case 2, the sliding movement of the seat pipe 7 in the radial direction allows smooth sliding between the main piston and the valve 5. Because the material is held in place, there is no wear due to deviation. Moreover, the machining accuracy of the sheet pipe 7 is not required to be so high.

As explained in detail above, in the present invention, the base of the seat pipe is attached to the bottom case so that it can slide in the radial direction, so there is no wear due to deviation, the damping operation is smooth, and the life is long. There is a certain effect. Moreover, the sheet pipe can be easily processed and can be obtained at low cost.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the sheet pipe installation device of the present invention, and FIG. 2 is a cross-sectional view of essential parts similarly showing another embodiment of the present invention. 1...Fork pipe, 2...Bottom case,
7... Seat pipe, 8... Bolt, 8a... Step part, 9... Nut, 9a... Step part, 10...
Oil lock piece.

Claims (1)

[Claims] 1. A fork pipe having a main piston at the tip is slidably fitted into a bottom case filled with oil, while a sub piston at the tip of a sheet pipe planted from the bottom of the bottom case is slid into the fork pipe. In the front fork that is freely inserted, the base of the seat pipe is bottomed, a hole is provided in the center, and when the bolt and nut are screwed together through the oil lock piece, there is a step on either the bolt or the nut. A device for installing a seat pipe in a front fork, characterized in that only the seat pipe is slidable in the radial direction.