JPS63151593A - Front fork - 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] (Industrial application field) -Input on improvements.

(Prior Art) For example, there is an inverted front oak as shown in FIG. 2, which is installed between the body and the front wheels of a two-wheeled vehicle. This has an inner tube 2 slidably inserted inside an outer tube 1 held on the vehicle body side, and the inner tube 2 is connected to a single shaft via a bottom member 26. A damper cylinder 4 is erected inside the inner tube 2, and as a piston 5 slides inside the damper cylinder 4, hydraulic oil flows through the inner tube 2, and its flow resistance generates a reducing force. Piston rod 10 of piston 5
is supported by a rod guide 3 fixed to the upper end of the inner tube 2 and freely slides into the inner tube 1, and its end is supported by the proximal end of the outer tube 1. Further, a suspension spring 16 is interposed between the base end portion of the outer chain 11 and the rod guide 3.

(Problems to be Solved by the Invention) In this case, while the piston 5 has been fully displaced to the length 3, the outer tube 1 and the inner tube 2 are still fitted over a length l-2.

This fitting length 11 is necessary to maintain the rigidity of the front fork, but during compression side operation, the tip of the tube 1 interferes with the bottom member 26 before the piston 5 reaches the bottom of the damper cylinder 4. As a result, the effective stroke 12 of the front fork becomes much shorter than the sliding distance of the piston 5. Therefore, in order to ensure a sufficient effective stroke 12, the inner tube 2 and damper cylinder 4 must be rotated (as a result, the overall length of the front 7 oak becomes longer and cannot fit between the vehicle body and the axle). Otherwise, the housing space for the suspension spring 16 may be narrowed, making it impossible to obtain desired spring characteristics.

The present invention aims to solve these problems with the conventional 70-ton 7-oak by providing a front 7-oak that can provide a sufficient effective stroke without increasing the overall length or narrowing the storage space for the suspension spring. With the goal.

(Means for solving the problem α) The present invention includes an inner tube that is slidably inserted inside an outer tube, a damper cylinder that is coaxially housed in the inner tube, and a damper cylinder that is housed in the damper cylinder. Connect the piston rod of the piston to the 7-tube tube,
In the front 7 oak, a rod guide that supports the piston rod so that it can slide freely is fixed inside the inner tube, and an S-frame spring is interposed between the rod guide and the outer tube. It is formed in the middle, and the effective stroke of 70 to 7 years approximately matches the piston sliding distance of the damper cylinder.

(Function) The rod guide is formed in the middle of the inner tube, and the effective stroke of the front 7t is made almost equal to the sliding distance of the piston. The effective stroke of the front fork is increased without reducing the housing space for the spring and while ensuring a predetermined fitting length between the outer tube and the inner tube.

(Example) FIG. 1 shows an embodiment of the present invention.

The figure shows an inverted 70-ton 7-year-old child, with 1 being an outer tube and 2 being an inner tube slidably inserted into the outer tube 1. The basis of outer tube 1! The @ portion is supported by the vehicle body, and the base end portion of the inner tube 2 is attached to the axle via the bottom member 26. The 7-outer tie 1 and the inner tube 2 are slidably supported by a bearing 21 and a seal 22 provided at the upper end of the inner tube 2, and a bearing 23 and a guest seal 24 provided at the lower end of the 7-outer tie 1.

A rod guide 3 is fixed in the middle of the inner tube 2, and a damper cylinder 4 housing a freely sliding piston 5 is erected from the bottom of the inner tube 2 toward the rod guide 3. Ru.

The fixed position of the rod guide 3 is determined according to the fitting length of the outer tube 1 and the inner tube 2 necessary to ensure the rigidity of the front 7 oak when it is fully extended.

A piston 5 is slidably housed inside the damper cylinder 4, and oil chambers A and B filled with hydraulic oil are formed on both sides of the piston 5. The piston 5 is provided with a check valve 6 that allows hydraulic oil to flow only from the oil chamber B to the oil chamber A without resistance,
A needle valve 7 is provided in parallel to provide a predetermined resistance to oil passage from oil chamber A to oil chamber B to generate a rebound damping force. Further, an oil reservoir chamber C is formed on the outside of the damper cylinder 4, and the hydraulic oil in the oil chamber B is supplied to the bottom of the damper cylinder 4 in this oil reservoir chamber C.
A needle valve 8 that allows oil to flow out while generating a pressure-side damping force, and a check valve 9 that only allows oil to flow in the opposite direction without resistance are provided in parallel. Piston 5 is piston rod 10
The piston rod 10 is slidably supported by the rod guide 3 and protrudes into the outer tube 1, and its end is formed at the upper end of the outer tube 1 with a cushion 1.
It is attached via 1 and 12. The position of the piston 5 is 7 at the lower end of tube 1 (bearing 23, guest seal 2
The length of the piston rod 10 is set so that it is close to 4), and the sliding distance of the piston 5 is 7.
It almost matches the effective stroke of . Note that an adjustment rod 13 for adjusting the opening degree of the needle valve 7 from the outside is inserted through the piston rod 10.

The inner tube 2 above the rod guide 3 opens into the outer tube 1, and an air spring chamber containing regulating oil and air is formed therein. At the bottom of this air spring chamber, a cylindrical oil lock case 14 through which the piston rod 10 freely slides is fixedly installed back to back with the rod guide 3, and a lock piece 15 that fits into this case is attached to the piston rod 10. It will be permanently installed. The fixing position of the lock piece 15 is determined so that it fits into the oil lock case 14 near the membrane pressure position of the piston 5. Further, a suspension spring 16 is interposed between the oil lock case 14 and the base end of the seventh tube 1 through an air spring chamber. Note that 17, 18, and 19 are seals for blocking the top and bottom of the rod guide 3, and 20 is a spring for preventing the piston 5 from fully extending. Further, 25 is a holder for the spring 20, which is attached to the piston rod 10.

Next, the effect will be explained.

When the 70 ton is moved to the pressure side from the position shown in FIG. The hydraulic oil corresponding to the volume entered by the piston rod 10 flows out into the oil reservoir chamber C through the needle valve 8 while generating a crushing force. At the same time, inner tube 2 is 7
By entering the air spring chamber, the compressed air and the suspension spring 16 repel the contraction of the front 7 oak. Note that this spring load can be arbitrarily set in advance by adjusting the amount of regulating oil sealed in the air spring chamber. In this way, as the piston 5 approaches the grain pressure position, the bottom member 1 also approaches the bottom member 26, and eventually the lock piece 15 attached to the piston rod 10 fits into the oil lock case 14. As a result, oil lock case 1
4 decreases, and the adjustment oil inside flows out from the gap with the oil piece 15, but as the lock piece 15 enters, the flow becomes difficult, and the contraction of the front 7 oak is prevented by a strong force. Therefore, there is no risk of the piston 5 bottoming out or the outer tube 1 colliding with the bottom member 26.

On the other hand, when the front fork shifts to the extension side operation, the upward displacement of the piston 5 causes the hydraulic oil in the oil chamber A to flow through the needle valve 7 and into the oil chamber B while generating the extension side destructive force. The hydraulic oil that had flowed out to the oil chamber B flows back to the oil chamber B from the check valve 9. However, as the piston 5 approaches the most extended position, its upward displacement is restricted by the spring 20 as shown in the figure, so the piston 5 does not collide with the rod guide 18, and even at this most extended position, the inner tube 2 is still fitted over a sufficient length to the outer tube 1, so there is no fear that the rigidity of the 7-inch fork will be insufficient.

The expansion and contraction of the front 7 oak is performed as described above,
Since the distance until the outer tube 1 comes into contact with the bottom member 26 is approximately equal to the sliding distance of the piston 5, a large effective stroke can be obtained. Since the length of the spring and the volume of the air spring chamber are sufficient, it provides a sufficient buffering function even against large impacts.

Although the above is an example in which the present invention is applied to an inverted type front fork, the same effect as described above can be obtained in an upright type 7a and 7oak.

(Effects of the Invention) As described above, the present invention forms a rod guide in the middle of the inner tube that oil-tightly and slidably supports the piston rod inserted into the inner tube from the outer tube. The effective stroke of the piston is made to almost match the sliding distance of the piston in the inner tube, so while ensuring the specified mating length of the outer tube and inner tube, the overall length of the front 7 oak and the accommodation space for the onkaku spring can be reduced. By lengthening the effective stroke of the shock absorber without changing it, the shock absorbing function will be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a front 7 oak showing an embodiment of the present invention, and FIG. 2 is a schematic sectional view of a front fork showing a conventional example. 1... Outer tube, 2... Inner chape, 3
...Rod〃id, 4...Gunpashi ring, 5...
・Piston, 10...Piston rod v116...Suspension spring. Patent applicant Kayabae Gyo Co., Ltd. Figure 2

Claims (1)

[Claims] The inner tube is slidably inserted inside the outer tube, the damper cylinder is coaxially housed in the inner tube, the piston rod of the piston housed in the damper cylinder is connected to the outer tube, and the piston rod is connected to the outer tube. In a front fork in which a rod guide that is freely slidably supported in the middle is fixed inside the inner tube, and a suspension spring is interposed between the rod guide and the outer tube, the rod guide is formed in the middle of the inner tube. , and the effective stroke of the front fork is made approximately equal to the piston sliding distance of the damper cylinder.