JP2600263Y2 - Front fork - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front fork having a vehicle height adjusting function.

[0002]

2. Description of the Related Art For example, in an on-off type motorcycle, the height of the vehicle body is increased so that the bottom of the vehicle body does not collide with a road surface during off-road driving. However, when traveling on a road with little unevenness in such an on / off road type vehicle, a high vehicle height is not necessary, but rather a request to adjust the vehicle height to a low vehicle height corresponding to the length of the rider's foot. There is.

As a means for adjusting the vehicle height for this purpose, for example, there is a method in which the initial load is changed by adjusting the position of a spring seat of a suspension spring suspended between a cylinder and a piston rod. In this case, the distance between the upper and lower spring seats does not actually change when riding, but the amount of piston rod entering the cylinder changes.In this method, not only the bump stroke but also the rebound stroke changes. The driver feels strangeness before and after adjusting the vehicle height.

Therefore, Japanese Patent Laid-Open Publication No. Hei 2-31036 or Japanese Utility Model Laid-Open Publication No. Hei 2-29886 proposes a vehicle height adjustment without changing the spring load. JP-A-2-
Japanese Patent No. 31036 discloses that an adjustment cylinder fixed to a wheel-side mounting bracket has a piston rod penetrated therein, and a piston fixed to the piston rod defines two oil chambers in the adjustment cylinder. The vehicle height is adjusted by connecting a cylindrical spring seat slidably disposed outside the adjusting cylinder and the piston rod, filling oil into one oil chamber and draining oil from the other oil chamber. I have to. Further, Japanese Unexamined Utility Model Publication No. 2-29886 discloses a front fork in which a vehicle body side tube on which a piston rod is mounted and a wheel side tube on which a cylinder is mounted are slidably fitted. A male screw part is formed in the part, and a female screw part screwed to the male screw part is formed in a lid member for attaching the piston rod to the body side tube, and the initial load of the suspension spring is changed by rotating the lid member. The height of the vehicle is adjusted by changing the relative position of the tube on the vehicle body side with respect to the piston rod without causing the piston rod to move. In both the former and the latter, the bump stroke is adjusted in conjunction with the vehicle height adjustment so that the distance between the fender mounted on the vehicle body and the tire at the time of maximum compression is kept constant to prevent mutual interference.

[0005]

Problems to be Solved by the Invention
According to the means disclosed in Japanese Patent Publication No. 1036 or Japanese Utility Model Application Laid-Open No. 2-29886, the vehicle height can be adjusted without changing the spring load and without changing the stroke distribution between the bumps and the rebound. There is no uncomfortable feeling before and after the vehicle, but the structure of the vehicle height adjustment is complicated and the adjustment operation is troublesome.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a vehicle body side tube and a wheel side tube which are slidably fitted to each other, a cylinder is mounted in the wheel side tube, and the cylinder is attached to the vehicle body side tube. In a front fork provided with a piston rod having a piston that is in sliding contact with an inner peripheral surface thereof and a suspension spring provided between the body-side tube and the wheel-side tube, the front fork is provided without changing the spring load of the suspension spring. the vehicle height adjusting member different fork bolt or the like having a length that varies the relative position of the vehicle body side tube and capable disposed replaced between the piston rod and the vehicle body-side tube relative, and the front follower
The stroke of compression stroke is
Is regulated between

[0007]

When the long vehicle height adjusting member is replaced with a short vehicle height adjusting member, the vehicle body side tube moves relative to the piston rod by the shortened length, and the vehicle height decreases. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a side view of a front portion of a motorcycle to which the front fork according to the present invention is applied, FIG. 2 is a cross-sectional view of the front fork in a fully extended state, and FIG. It is a principal part expanded sectional view at the time of extension. In addition, in FIG. 2, a long fork bolt is
The left side shows a short fork bolt attached.

The front fork 1 is provided as a pair of left and right,
The vehicle body side tube 11 of each front fork 1 is supported by a steering shaft in the head tube 4 via bridges 2 and 3, supports the wheel 5 at the lower end of each vehicle body side tube, and further has a fender on the lower surface of the lower bridge 3. 6 is attached.

The structure of the front fork 1 is such that a vehicle body side tube 11 and a wheel side tube 12 are slidably fitted to each other, a damper cylinder 13 is mounted on the bottom of the wheel side tube 12, and an upper end of the vehicle body side tube 11 is provided. Fork bolt 14a or fork bolt 14b as vehicle height adjusting member
The piston 16 fixed to the lower end of the piston rod 15 is slidably in contact with the inner peripheral surface of the damper cylinder 13.

The upper end of the piston rod 15 is screwed into a fork bolt 14a or 14b and fixed by a lock nut 17, and the lower end of the lock nut 17 supports an upper spring seat 18; A lower spring seat 19 is supported at the upper end, and a suspension spring 20 is compressed between the spring seats 18 and 19. The upper spring seat 1
The position 8 is not limited to the above, and may be fixed at an intermediate position of the piston rod 15 .

Further, an oil lock collar 21 is provided on an inner peripheral portion of a lower end of the vehicle body side tube 11, and an oil lock piece 22 is provided on an outer peripheral portion of a lower end of the wheel side tube 12, and the oil lock collar 21 and the oil lock piece 22 are provided. The front fork 1 is in the most compressed state at the fitted position.

In the above, in order to lower the vehicle height, the fork bolts are changed from the long fork bolts 14a to the short fork bolts 14b. Then, as shown in FIG. 2, the length between the center of the axle mounting bracket 26 of the front fork and the upper end of the fork bolt at the time of maximum extension is L.
The vehicle height changes from 1 to L1 ', and the vehicle height decreases by L1-L1'.

At this time, the bump stroke changes from L2 to L2 ', and this change is equal to the difference T in the length between the fork bolts 14a and 14b. Also,
The rebound stroke L3 does not change before and after the vehicle height adjustment.

In the illustrated example, the fork bolts 14a and 14b having different lengths are shown as the vehicle height adjusting members. However, as shown in FIG. 3, between the upper end of the piston rod 15 and the fork bolt 14b. The spacer 24 may be interposed.

[0016]

[Effects of the Invention] As described above, according to the present invention,
The vehicle height can be changed without changing the spring load only by replacing the vehicle height adjusting member such as a fork bolt, and the structure is extremely simple and advantageous in cost as compared with the related art. Further, if the compression stroke of the front fork is regulated between the vehicle body side tube and the wheel side tube as shown in FIG. 2, the amount of down adjustment of the vehicle height and the amount of shortening the compression stroke become equal. Also, interference between the wheels and the fender attached to the vehicle body does not occur.

[Brief description of the drawings]

FIG. 1 is a side view of a front portion of a motorcycle to which a front fork according to the present invention is applied.

FIG. 2 is a cross-sectional view of the front fork when it is fully extended.

FIG. 3 is an enlarged sectional view of a main part of a front fork according to another embodiment when the front fork is fully extended.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Front fork, 11 ... Body side tube, 12 ...
Wheel side tube, 13 ... damper cylinder, 14a, 14
b: Fork bolt, 15: Piston rod, 16: Piston, 18, 19: Spring seat, 20: Suspension spring, 24: Spacer, L1, L1 '... Fork bolt from center of axle mounting bracket of front fork at maximum extension L2, L2 ': bump stroke, L3: rebound stroke, T: difference in length between long and short fork bolts.

Claims (3)

(57) [Scope of request for utility model registration] 1. A vehicle body side tube and a wheel side tube are slidably fitted to each other, and a cylinder is mounted in the wheel side tube.
In a front fork in which a piston rod having a piston slidingly contacting the inner peripheral surface of the cylinder is fixed to a vehicle body side tube and a suspension spring is provided between the vehicle body side tube and the wheel side tube, the front fork has a spring load of the suspension spring. A height-adjusting member having a different length for changing the relative position of the vehicle body-side tube with respect to the piston rod without changing the piston rod is replaceably disposed between the piston rod and the vehicle body-side tube , and a compression fork of the front fork is provided.
The troke is regulated between the body tube and the wheel tube.
A front fork characterized by being controlled . 2. A front fork according to claim 1 Symbol placement, wherein the vehicle height adjusting member is a different fork bolt lengths. 3. A front fork according to claim 1 Symbol placement, wherein the vehicle height adjusting member is a spacer which is interposed between the base end portion of the piston rod and the fork bolt.