JPH09196103A - Front fork - Google Patents

Abstract

(57) Abstract: A spring fork supporting a lower end of a suspension spring is provided in a front fork set deep inside a lower end of an inner tube as an axle side tube, and durability of the spring is reduced. Without using the tool, the damper can be pulled out, making it ideal for mounting on a motorcycle with road racing specifications. SOLUTION: A spring receiver 12 having a damper upright inside and carrying a lower end of a suspension spring 8 for urging an outer tube 1 as a vehicle body side tube and an inner tube 2 as an axle side tube in an extension direction. The knuckle bracket 7 screwed to the lower end of the inner tube 2 has a locking portion 12a at the upper end for connecting a tool inserted between the suspension spring 8 and the cylinder body 3 forming the damper, and the cylinder is provided at the lower end. Valve block 3 screwed to the lower end of body 3
Engagement portion 1 with which the engagement portion 32a formed on the outer periphery of the lower end of 2 engages
2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front fork mounted on a motorcycle, and more particularly to an improvement of a front fork mounted on a road racing motorcycle.

[0002]

2. Description of the Related Art In a road race of a motorcycle, a front fork mounted on the motorcycle is completely replaced with a so-called cartridge damper so that the front fork has an optimum damping characteristic. There are many things to do.

The replacement of the damper is realized by pulling out the damper housed in the front fork, and it is said that the hydraulic oil is prevented from flowing out as much as possible when the damper is pulled out. There is.

Therefore, as a front fork that meets such a demand, for example, as shown in FIG. 2, the upper end side of an inner tube 2 as an axle side tube slides inside the lower end side of an outer tube 1 as a vehicle body side tube. There is an upright type front fork that is movably inserted, and a damper is installed upright.

That is, in the damper, the cylinder body 3 constituting the damper is erected at the axial center portion of the inner tube 2, and the piston also constitutes the damper while being connected to the cylinder body 3 so as to be retractable. The rod body 4 is arranged at the axial center of the outer tube 1.

By the way, in the damper, as shown in FIG. 3, a valve block 32 having a base valve (not shown) at the lower end opening of a cylinder 31 constituting the cylinder body 3.
It is configured to be closed by screwing.

The valve block 32, that is, the lower end of the cylinder 31, is a knuckle for connecting an axle (not shown) of a front wheel (not shown) by tightening a tightening bolt 6 with a ring nut 5 interposed. It is supposed to be connected to the bracket 7.

On the upper end side of the knuckle bracket 7,
The lower end of the inner tube 2 is screwed, and in this state, a space between the inner circumference of the inner tube 2 and the outer circumference of the cylinder 31 is set as a reservoir chamber R in which the suspension spring 8 is also arranged. R communicates with the above-mentioned air chamber with an oil surface (not shown) as a boundary.

On the other hand, the valve block 32 has an engaging portion 32a, which is formed in the shape of, for example, a hexagonal nut, which projects from the outer periphery of the cylinder 31 on the outer periphery of the lower end thereof.
It is supposed that an appropriate tool that is inserted between the cylinder 31 and the inner tube 2, and more precisely between the cylinder 31 and the suspension spring 8 is connected to the locking portion 32a.

Therefore, in the above-mentioned conventional front fork, the piston rod body 4 and the outer tube 1 are
By loosening and removing the cap nut 9 (see FIG. 2) that connects the and the outer tube 1, the outer tube 1 can be lowered with respect to the inner tube 2, and the upper end of the piston rod body 4 can be intersected with the piston rod body 4. It is possible to remove the spring guide 10 (see FIG. 2), the spacer 11 (see FIG. 2) and the suspension spring 8 which are provided on the outer peripheral side of the.

Then, with the spring guide 10, the spacer 11 and the suspension spring 8 removed, the cylinder 3
1 is a ring nut of the valve block 32 integrally provided with the cylinder 31 by a turning operation of an appropriate tool which is inserted through between the inner tube 2 and the inner tube 2 and is connected to a locking portion 32a formed on the valve block 32. 5 can be separated from the ring nut 5, and the cylinder body 3 can be separated from the ring nut 5.
Can be separated from the knuckle bracket 7, that is, the damper can be removed from the inner tube 2.

At this time, the hydraulic oil in the cylinder 31 flows out from the so-called opening of the valve block 32 and remains on the inner peripheral side of the inner tube 2. The lower end of the inner tube 2 is, so to speak. Since the axial center portion of the knuckle bracket 7 that closes is closed by the ring nut 5, the tightening bolt 6, and the like, so-called leakage to the outside is prevented.

[0013]

However, in the above-described conventional front fork, it is pointed out that the durability of the front fork is lowered or the damper may be difficult to pull out.

That is, in the above-mentioned conventional front fork, the spring for supporting the lower end of the suspension spring 8 disposed between the inner peripheral side of the inner tube 2 and the outer peripheral side of the cylinder body 3 constituting the damper. An inner peripheral stepped portion 7 formed on a knuckle bracket 7 in which a receiver 12 continuously connects the lower ends of the inner tubes 2.
Since it is held at a and is set in a deep place, so to speak, it becomes difficult to extract the spring receiver 12 to the outside without leaking the hydraulic oil to the outside.

Accordingly, the valve block 32 is rotated by separating the valve block 32 from the ring nut 5 by rotating the appropriate tool, that is, inserting the tool between the cylinder 31 and the spring bearing 12. In order to improve the operability at the time of doing, the spring bearing 12 must be formed so-called small so as to secure a gap sufficient for inserting a tool between the cylinder 31 and the spring bearing 12. become.

When the spring bearing 12 is so-called small, the seat surface for carrying the suspension spring 8 on the spring bearing 12 becomes small, and the suspension spring 8 cannot be held in a stable state.

When the spring bearing 12 is intentionally thickened in the inner diameter direction to secure a sufficient seating surface, it is sufficient to insert a tool between the spring bearing 12 and the cylinder 31. It becomes impossible to secure the gap that becomes
There is a danger that it will be difficult to remove the damper.

The present invention was devised in view of the above-mentioned circumstances, and an object thereof is to provide a spring bearing for supporting a lower end of a suspension spring at a so-called deep portion of a lower end of an inner tube as an axle side tube. Provides a front fork that is optimal for being mounted on a road-race motorcycle, even if it is set, allowing the damper to be pulled out using tools without lowering the durability of the spring bearing. It is to be.

[0019]

In order to achieve the above object, the structure of the present invention is provided so that the upper end side of an inner tube as an axle side tube can slide within the lower end side of an outer tube as a vehicle body side tube. A cylinder body that is inserted and constitutes a damper is erected on the axial center portion of the inner tube, and a piston rod body that constitutes the damper and is connected to the cylinder body so as to be retractable is disposed at the axial center portion of the outer tube. , A suspension spring for urging the inner tube to project from the outer tube is arranged on the inner peripheral side of the inner tube and the outer peripheral side of the cylinder body,
In a front fork in which a spring receiver carrying the lower end of the suspension spring is supported by a knuckle bracket screwed to the lower end of the inner tube, the spring receiver connects the tool inserted between the suspension spring and the cylinder body to the upper end. It is assumed that the engaging portion has an engaging portion and that the lower end has an engaging portion with which the engaging portion formed is engaged with the outer periphery of the lower end of the valve block screwed to the lower end of the cylinder body.

It is preferable that the spring bearing is landed on the inner bottom landing portion of the knuckle bracket for landing the ring nut screwed on the inner circumference of the lower end of the valve block.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings. Basically, the front fork according to the embodiment of the present invention is basically the same as the above-mentioned conventional front fork (see FIG. 2). (See) is configured similarly.

Therefore, in the illustrated embodiment, the parts having the same configurations are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted unless necessary. The main features of the present invention will be described.

That is, according to the present invention, as shown in FIG. 1, the spring receiver 12 that carries the lower end of the suspension spring 8 is engaged with the tool that inserts between the cylinder 31 and the inner tube 2 at the upper end. The valve block 3 having the portion 12a and screwed to the lower end of the cylinder 31 at the lower end.
Engagement portion 1 with which the engagement portion 32a formed on the outer periphery of the lower end of 2 engages
2b.

In the illustrated embodiment, the state in which the locking portion 32a of the valve block 32 and the engaging portion 12b of the spring receiver 12 are connected is maintained by mounting the stop ring 13 on the engaging portion 12b. I am trying.

On the other hand, in the present invention, the spring bearing 12 is
The inner bottom landing portion 7b formed on the knuckle bracket 7 that connects the lower ends of the inner tubes 2 to each other, that is, the inner bottom landing portion 7b on which the ring nut 5 is landed, is grounded.

Therefore, in the spring receiver 12 according to the present invention, the cylinder 31 is rotated by operating the tool which is inserted between the cylinder 31 and the inner tube 2 and is connected to the locking portion 12a. In other words, the valve block 32, which is integrally provided, can be separated from the ring nut 5.

At this time, in the above-mentioned conventional front fork, the engaging portion 32a with which the tool is connected is provided with the spring bearing 1.
Since the tool is arranged below 2, the tool must be inserted so as to intersect the spring bearing 12, and therefore the operability when inserting the tool is deteriorated.

However, according to the present invention, since the engaging portion 12a with which the tool is connected is formed at the upper end of the spring bearing 12, the tool cannot be inserted while the spring bearing 12 is crossed. Is not introduced, and therefore the tool is not
This is advantageous in that the operability when connecting to 2a is improved.

Next, in the spring bearing 12 of the present invention,
Since it is assumed that the lower end is grounded and supported by the inner bottom landing portion 7b, the spring bearing 12 can be formed to be thick as a whole, and weakening of the spring bearing 12 can be avoided.

That is, in the above-mentioned conventional front fork, since the spring receiver 12 is supported by the inner peripheral stepped portion 7a formed on the knuckle bracket 7, the inner peripheral stepped portion 7a is formed. However, there is a problem that the wall thickness of the spring bearing 12 cannot be increased in the inner diameter direction, and therefore the spring bearing 12 is easily weakened as a whole.

However, in the present invention, the spring bridge 12
As described above, since the lower end is landed on and supported by the inner bottom landing portion 7b, the inner circumferential step portion 7a described above is
Therefore, it is possible to increase the inner diameter of the corresponding portion of the knuckle bracket 7.

Therefore, the region where the spring bearing 12 is distributed becomes wider, and the spring bearing 12 can be made thicker as a whole, and as a result, weakening of the spring bearing 12 is avoided. It is advantageous in that it can be done.

Moreover, according to the present invention, the spring receiver 12
Since the whole can be formed thick, the above-mentioned locking portion 12
It goes without saying that the formation of a and the engaging portion 12b is facilitated, and in particular, the engaging portion 12a can be effectively formed from a mechanical point of view, and thus the above-mentioned connectivity of the tools is improved. That is, a large torque can be applied when the tool is rotated, which is also advantageous in that the so-called operability when using the tool is improved.

[0034]

As described above, according to the present invention, the spring bearing carrying the lower end of the suspension spring connects the tool inserted at the upper end between the inner tube and the cylinder forming the cylinder body of the damper. It is assumed that the tool has a locking portion and the lower end has an engaging portion with which the locking portion formed is engaged with the outer periphery of the lower end of the valve block screwed to the lower end of the cylinder. It becomes possible to rotate by connecting to the locking portion formed on the upper end of the receiver, and as a result, it becomes possible to separate the valve block integrally having the cylinder from the ring nut, and to remove it from the ring nut. By the separation, the cylinder body can be separated from the knuckle bracket, that is, the damper can be pulled out from the inner tube.

At this time, since it is assumed that the engaging portion for connecting the tools is formed at the upper end of the spring bearing, there is no problem that the tool is inserted while intersecting the spring bearings, and therefore,
There is an advantage that the operability when connecting the tool to the locking portion is improved.

Further, in the present invention, since the spring bearing is supported by the inner bottom landing portion of the knuckle bracket, the spring bearing can be formed thick as a whole.
This makes it possible to avoid weakening the spring bearing.

Further, since the spring bearing can be formed to be thick as a whole, it is easy to form the above-mentioned engaging portion and engaging portion, and in particular, the engaging portion is mechanically effective. Since it is possible to form the shape of the tool, it is possible to improve the connection of the tools, and it is possible to apply a large torque when rotating the tools, which improves the so-called operability when using the tools. It is also advantageous in terms of

As a result, according to the present invention, in the front fork in which the spring bearing for supporting the lower end of the suspension spring is set at the so-called deep portion of the lower end of the inner tube as the axle side tube, the durability of the spring bearing is improved. There is an advantage that the damper can be pulled out by using a tool without deteriorating the performance, and it is most suitable for mounting on a motorcycle of road race specification.

[Brief description of the drawings]

FIG. 1 is a partial front view showing a partially cutaway lower end portion of a front fork according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view showing a front fork as a conventional example.

FIG. 3 is a partial front view showing the lower end portion of the front fork of FIG. 2 similarly to FIG.

[Explanation of symbols]

 1 Outer tube as a vehicle body side tube 2 Inner tube as an axle side tube 3 Cylinder body constituting a damper 4 Piston lodder constituting a damper 5 Ring nut 7 Knuckle bracket 7b Inner bottom landing portion 8 Suspension spring 12 Spring bearing 12a, 32a Locking part 12b Engaging part 32 Valve block

Claims (2)

[Claims] 1. An upper end side of an inner tube as an axle side tube is slidably inserted into a lower end side of an outer tube as a vehicle body side tube, and a cylinder body constituting a damper is erected at an axial center portion of the inner tube. The piston rod body, which constitutes the damper and is connected to the cylinder body so as to be retractable, is arranged at the axial center of the outer tube, and the suspension spring that urges the inner tube to protrude from the inner tube is In the front fork, which is arranged on the inner peripheral side of the tube and on the outer peripheral side of the cylinder body, and in which a spring receiver that carries the lower end of the suspension spring is supported by a knuckle bracket that is screwed onto the lower end of the inner tube, Has a locking portion at the upper end for connecting a tool inserted between the suspension spring and the cylinder body, and a cylinder at the lower end. A front fork characterized in that it has an engaging portion with which a formed engaging portion engages with the outer periphery of the lower end of a valve block screwed to the lower end of the body. 2. The front fork according to claim 1, wherein the spring bearing is landed on an inner bottom landing portion of a knuckle bracket for landing a ring nut screwed on the inner circumference of the lower end of the valve block.