JP2001280395A - Shock mitigation structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a predetermined shock-mitigating function in multiple stages, and to enable a permanent display of the shock-mitigating function. SOLUTION: In an impact mitigation structure having an oil lock piece 4 disposed on an axle side tube 1 and an oil lock collar 5 disposed on a vehicle body side tube 2, the oil lock piece 4 is disposed on the axle side tube 1. Bottom part 1a
In addition to the adjusting pipe 14 which is arranged to be able to move up and down by operating the operation unit 20 disposed in the seat pipe 3, the adjusting pipe 14 is arranged so as to be able to move up and down in the axis of the seat pipe 3. A guide pin 10 having both ends penetrating a vertically extending guide hole 3 e formed in the lower end of the sheet pipe 3 while supporting the lower end of the guide pin 10 at an intermediate portion, and both ends of the guide pin 10 Is connected to a cylinder 16 disposed between the outer periphery of the lower end portion of the seat pipe 3 and the inner periphery of the oil lock piece 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a shock absorbing structure provided on a front fork mounted on a front wheel side of a motorcycle for reducing an impact at the time of a maximum compression operation of the front fork.

[0002]

2. Description of the Related Art Conventionally, a front fork mounted on a front wheel side of a motorcycle has conventionally been provided with an impact mitigation structure for alleviating an impact at the time of a maximum compression operation. Although various proposals have been made so far, on the other hand, for example, a shock absorbing structure having a new configuration shown in FIG. 6 can be proposed.

That is, as shown in FIGS. 6 and 7, this shock absorbing structure enables the height position of the oil lock piece 4 to be changed by operating the operation portion 20 and also allows the oil lock piece 4 to be raised when it is raised. , For example, the suspension spring 13
It is stated that the spring force of the front fork (see FIG. 9) can be increased to effectively reduce the impact at the time of the maximum compression operation of the front fork.

[0004] To briefly explain the outline, in this shock absorbing structure, first, an oil lock piece 4 is provided at an outer periphery of a lower end portion of a seat pipe 3 fixed to an axle portion of an axle side tube 1. As shown in FIG. 8, it is arranged so as to be raised by a lock pressure that stands in an oil lock chamber R partitioned on the rear side.

On the other hand, as shown in FIG. 9, an oil lock collar 5 is held on the inner periphery of the lower end of the vehicle body side tube 2 which is protruded into and retracted from the axle side tube 1. At the time of lowering, the oil lock piece 4 is fitted on the inner peripheral side (see FIG. 8).

Therefore, according to this shock absorbing structure, the axle-side tube 1 can be moved with a large stroke by the vehicle-body-side tube 2.
When the oil lock piece 4 is fitted into the oil lock collar 5 at the time of the maximum compression operation to be immersed in the oil, the oil from the oil lock chamber R partitioned behind the oil lock piece 4 appears between the two. You will escape through the gap.

As a result, the speed at which the body-side tube 2 enters the axle-side tube 1 is reduced by the flow path resistance generated by the passage of the oil through the gap, and the lock pressure standing in the oil lock chamber R is further reduced. As a result, the vehicle body side tube 2 is prevented from further immersing into the axle side tube 1, that is, further compression of the front fork is prevented, and the impact of the front fork caused by so-called bottoming can be reduced.

Incidentally, in this shock absorbing structure, the oil lock piece 4 is operated via an elevating piston 23 by operating an operating portion 20 disposed on the outer periphery of the bottom portion 1a of the axle-side tube 1. Is raised and lowered (see FIG. 7).

Therefore, when the oil lock piece 4 is raised by the operation of the operation section 20, the compression speed of the front fork is reduced and the oil lock piece 4 is not raised. Shock mitigation is manifested as a short compression stroke.

On the other hand, the shock absorbing structure has an adjusting pipe 14 having an upper end extending upward on the inner peripheral side of the seat pipe 3 and seating the lower end of the adjusting pipe 14 while supporting the adjusting pipe 14 at an intermediate portion. A guide pin 10 having both ends penetrating a vertically extending guide hole 3 e formed in the lower end of the pipe 4, and both ends of the guide pin 10 are connected to the oil lock piece 4 by press fitting. It is going to be.

As shown in FIG. 9, the adjusting pipe 14 carries a lower end of the suspension spring 13 at a spring receiving portion 14a as an upper end.

Therefore, when the oil lock piece 4 is raised, the guide pin 10 is raised integrally with the oil lock piece 4, so that the lower end of the suspension spring 13 is raised. The spring force will be increased.

As a result, by increasing the spring force of the suspension spring 13, the compression speed of the front fork and the impact mitigation can be more effectively realized.

[0014]

However, it may be pointed out that in the above-described newly proposed shock absorbing structure, the desired shock absorbing function cannot be permanently exhibited.

That is, as a measure for improving the operability of the handlebar in a motorcycle, the front fork in recent years is made as light as possible. For example, the oil lock piece 4 is made of aluminum. Often formed.

On the other hand, in consideration of the function of the guide pin 10, iron having higher rigidity than aluminum is often used.

Therefore, even if this guide pin 10, that is, both ends of the guide pin 10 are press-fitted and connected to the oil lock piece 4, the holding force at that time, that is,
There is a concern that the oil lock piece 4 cannot be expected to exhibit great holding power.

As a result, the guide pin 10 is not connected to the oil lock piece 4 in the fixed state as set, and can move in the radial direction which is the left and right direction in the figure. The end of the guide pin 10 protrudes toward the outer peripheral side of the oil lock piece 4 and interferes with the oil lock collar 5. Therefore, the above-described proposed shock absorbing structure permanently exerts a predetermined shock absorbing function. There is a fear that it will not be possible to expect them to do so.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide not only a predetermined shock absorbing function but also a permanent shock absorbing function. It is an object of the present invention to provide an impact mitigation structure which is optimal for expecting an improvement in versatility of the front fork.

[0020]

In order to achieve the above-mentioned object, a structure of an impact mitigation structure according to the present invention is basically provided by a seat pipe fixedly disposed on a shaft core of an axle-side tube. An oil lock piece that is arranged on the outer peripheral side of the lower end portion so as to be able to ascend and descend and rises by a lock pressure that stands in an oil lock chamber partitioned behind the same.
In the shock absorbing structure having an oil lock collar which is held on the inner periphery of the lower end portion of the vehicle body side tube and fits the above oil lock piece on the inner peripheral side at the time of its lowest movement, the oil lock piece has an axle side tube In addition to having an adjustment pipe arranged so as to be able to ascend and descend to the shaft core portion of the seat pipe while operating the operation section disposed on the outer periphery of the bottom portion in A guide pin having both ends penetrating a vertically extending guide hole formed in the lower end of the seat pipe while supporting the lower end of the pipe at an intermediate portion, and both ends of the guide pin are seat pipes. Is connected to a cylinder disposed between the outer periphery of the lower end portion and the inner periphery of the oil lock piece.

More specifically, in the above-described configuration, more specifically, the adjustment pipe carries the lower end of a suspension spring whose upper end spring receiving portion urges the vehicle body side tube out of the axle side tube. Or a throttle resistance portion on the outer periphery in the vicinity of the upper end, and the throttle resistance portion is provided on the downstream side of the orifice which is opened by the sheet pipe to generate the extension damping force. I do.

The operating section has an elevating piston which is set adjacent to the lower end of the oil lock piece so as to be able to move up and down. Suppose the lock piece is raised.

Further, it is preferable that a valve for preventing generation of negative pressure noise is provided around the oil lock piece.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below on the basis of the illustrated embodiment. Even with the shock absorbing structure according to the present invention, basically, the shock absorbing structure proposed above is different from that of the present invention. The configuration is almost the same.

Therefore, in the following description, it is assumed that the features of the present invention will be described while explaining the points which have not been sufficiently explained in the above-mentioned proposal, and in that case, the structure of the above-mentioned proposal will be described. In the embodiment shown in the drawings, the same parts as those in the relaxation structure are given only the same reference numerals, and detailed description thereof will be omitted unless necessary.

First, in the shock absorbing structure according to the present invention, as shown in FIG. 1, both ends of the guide pin 10 are disposed between the outer periphery of the lower end of the seat pipe 3 and the inner periphery of the oil lock piece 4. And is connected to the cylindrical body 16.

As a result, the oil lock piece 4 functions as a stopper opposing both ends of the guide pin 10, so that both ends of the guide pin 10 cannot protrude to the outer peripheral side of the oil lock piece 4, and as a result, A situation in which both ends of the guide pin 10 protrude toward the outer peripheral side of the oil lock piece 4 and interfere with the oil lock collar 5 does not occur, so that the predetermined shock absorbing function can be exhibited permanently.

At this time, an intermediate portion of the guide pin 10 is disposed on a shaft portion serving as an inner peripheral side of the seat pipe 3 and a lower end of the adjusting pipe 14 having an upper end extending upward is connected to the seat member 15.
It is said to be carried under the intervention of.

Incidentally, the adjusting pipe 14 carries the lower end of the suspension spring 13 by the spring receiving portion 14a, which is the upper end thereof, similarly to the above-mentioned proposal. Orifice 3d that generates damping force
May be provided in the vicinity of the upper end of the aperture resistance portion 14c existing on the downstream side in FIG.

Then, the adjusting pipe 14 is connected to the throttle resistor 14.
In the case where the guide pin 10 is raised, the throttle resistor 14c adjusts the opening of the orifice 3d when the guide pin 10 is raised, so that different extension damping forces are generated.

At this time, the adjusting pipe 14 forms a gap as an oil flow path between the adjusting pipe 14 and the seat pipe 3, and the seat member 15 maintains this gap, that is, the adjusting pipe 14 is centered. Function as spacers.

Therefore, in the shock absorbing structure having the adjusting pipe 14, when the oil lock piece 5 rises, as shown in FIGS. As the guide pin 10 of the body 16 rises, the adjustment pipe 14 rises, and the lower end of the suspension spring 13 carried on the upper end of the adjustment pipe 14 rises, so that the spring force of the suspension spring 13 is increased. Become.

On the other hand, the seat pipe 3 is screwed into the lower threaded portion 3a of the tightening nut 7 inserted from below and externally into the shaft core of the bottom portion 1a of the axle-side tube 1 to thereby rotate the shaft of the outer tube 1. It is said to be standing upright on the core.

At this time, the guide hole 3e, which is opened in the sheet pipe 3 and penetrates both ends of the guide pin 10, is formed in the form of an elongated hole along the axial direction of the sheet pipe 3. Is set so as to have a length that does not hinder the upward movement in the guide hole 3e.

The lower end position of the guide hole 3e is set so as not to contact the lower end of the guide pin 10 when the oil lock piece 4 is lowered and is seated on the bottom portion 1a. Have been.

The seat pipe 3 penetrates the vicinity of the lower end, that is, a portion adjacent to the upper end of the oil lock piece 4 to be described later to enable communication between the inner peripheral side and the outer peripheral side. Has a through hole 3b that enables the generation of a compression-side damping force when oil passes through.

The upper end of the seat pipe 3 is located on the inner peripheral side of the lower end of the inner tube 2, and under this state, the seal 8 interposed on the outer periphery of the upper end enlarged diameter portion 3c is closed. Sliding contact with the inner circumference of the inner tube 2 blocks the communication between the upper side and the lower side of the upper end enlarged diameter portion 3c (see FIG. 6).

Incidentally, the orifice 3 is formed by drilling the lower part of the upper end enlarged diameter portion 3c in the vicinity of the upper end of the seat pipe 3.
d, a reservoir chamber R on the inner peripheral side of the seat pipe 3
It is said that it will communicate with 3.

Although not shown, the axle-side tube 1 having the seat pipe 3 at its axle portion has a lower end connected to the axle of the front wheel of the motorcycle, and is provided with a bearing 6 with respect to the axle-side tube 1. Although not shown, the body-side tube 2 to be protruded and retracted is connected to a bracket for fixing a steering wheel while its upper end is connected to the body of the motorcycle.

Further, the oil lock piece 4 is slidably interposed on the outer periphery of the cylindrical body 16 interposed on the outer periphery of the lower end portion of the above-mentioned seat pipe 3, and has the same thickness and appropriate thickness. A lower end side main body part 4a formed in a cylindrical shape having a length, and an upper end side oil hole rod part which is integrally connected to an upper end of the main body part 4a and extends upward and has an outer peripheral surface having a tapered surface 4b. 4c.

At this time, in the oil lock piece 4, the lower end of the main body 4a is
Is formed, and the area thereof is set smaller than the pressure receiving area on the inner tube 2 side.

At this time, the oil lock piece 4 has a flange 4d on the inner periphery of the lower end of the main body 4a.
6 is to be carried.

Incidentally, the above-mentioned oil hole rod portion 4c is formed with the above-mentioned tapered surface 4b so that the thickness thereof gradually decreases toward the upper end side.

On the other hand, the operating portion 20 which allows the oil lock piece 4 to be moved up and down is arranged on the outer periphery of the bottom portion 1a of the axle side tube 1 as shown in FIG. It has a lifting piston 23 which is set to be movable up and down. When the lifting piston 23 rises by the supply of an external force such as fluid pressure, the oil lock piece 4 is raised (see FIG. 2).

To explain a little, the operating section 20 moves the piston 22 forward by rotating the operation dial 21 as shown in the figure, and the oil storage chamber R
The oil of No. 4 flows into the pressure chamber R5, and the raising / lowering piston 23 that partitions the pressure chamber R5 is raised by the inflow of the oil.
The oil lock piece 4 is raised.

At this time, the communication passage 1c for communicating the oil storage chamber R4 with the pressure chamber R5 is set to exhibit a throttle effect.
About seal 22a for leak prevention interposed in
This need not be a high-pressure seal, and the seal 22
a can be improved in durability.

The operating section 20 is not shown, but is not shown. Instead of using a fluid pressure comprising a so-called pump as shown in the figure, an external force is transmitted mechanically without using a fluid pressure. May be configured.

When the hydraulic pressure is used, it is possible to use the oil to be charged into the front fork. When the mechanical means is used, the whole oil is used as compared with the case where the hydraulic pressure is used. The configuration can be simplified.

While the oil lock piece 4 is configured as described above, the oil lock collar 5 is held on the inner periphery of the lower end of the vehicle body side tube 2, but the upper and lower ends are pressurized and deformed. It is assumed that the lower end is fixed by being caulked and fixed to the inner periphery of the lower end of the vehicle body side tube 2 and has an extension side damping valve 11 on the inner peripheral side of the upper end. (See FIG. 6).

In the oil lock collar 5, the inside diameter of the intermediate portion, which is the so-called main body, is made to match the outside diameter of the main body 4a of the oil lock piece 4.

The extension damping valve 11 is mounted on the inner peripheral side of the upper end of the oil lock collar 5 so as to be able to move up and down, while being disposed at the upper end.
To maintain a so-called seated state, that is, a valve closed state.

The extension-side damping valve 11 has a gap (not shown and not shown) in the inner periphery on the lower end side in sliding contact with the outer periphery of the seat pipe 3. It has an annular groove 11a communicating with the lower gap on the inner circumference on the upper end side to be opposed, and forms an annular gap (not shown) between it and the outer circumference of the seat pipe 3.

The extension-side damping valve 11 has a cutout 11b on the outer peripheral side at the upper end, and when the extension-side damping valve 11 rises, the lower side of the extension-side damping valve 11 is provided. Care is taken so that the oil can flow upward without interruption.

Incidentally, with the arrangement of the extension side damping valve 11,
The extension side damping valve 1 on the outer peripheral side of the seat pipe 3
1 and an expansion oil chamber R1 is defined above, and the expansion damping valve 1
It is assumed that a pressure side oil chamber R2 is defined below the lower side 1 and, at this time, an inner peripheral side of the seat pipe 3 is a reservoir chamber R3.

The inner circumference of the cylindrical body 16 is set so as to be in sliding contact with the outer circumference of the lower end of the seat pipe 3 and the outer circumference is in sliding contact with the inner circumference of the oil lock piece 4. Both ends of the guide pin 10 are connected to the mounting hole 16a opened in the direction.

At this time, both ends of the guide pin 10 are opposed to the inner periphery of the oil lock piece 4, and the oil lock piece 4 functions as a so-called stopper.
It is not necessary that the guide pin 10 is press-fitted into the mounting hole 16a, and even if it is loosely inserted, both ends of the guide pin 10 do not protrude to the outer peripheral side of the oil lock piece 4.

Incidentally, the cylinder 16 is arranged to be placed on a flange 4d formed on the inner periphery of the lower end of the oil lock piece 4 described above.

In view of the above, as compared with the case where care must be taken to prevent both ends of the guide pin 10 from protruding to the outer periphery of the oil lock piece 4 in the new proposal described above, Are connected to the oil lock piece 4 in a fixed state.
It is advantageous that the cylindrical body 16 has a large holding force in the connection with the cylindrical body 16, so that it is not necessary to perform a fine processing in forming the mounting hole 16 a in the cylindrical body 16. Become.

As a result, even if the guide pin 10 is made of iron, not only the oil lock piece but also the cylinder 1
6 can be made of aluminum, so that there is no need to worry about an unnecessary increase in weight even if the number of components as the cylindrical body 16 increases.

Therefore, with the shock absorbing structure according to the present invention formed as described above while having the configuration of the above-described new proposal, the compression operation of the front fork with a large stroke is as follows. Will work.

That is, when the front fork is compressed with a large stroke, the oil lock collar 5 held on the inner periphery of the lower end of the inner tube 1 is provided on the bottom 1 a of the outer tube 1. 4 will be fitted.

At this time, at the start of the fitting, the oil from the bottom portion 1a through the gap formed between the inner periphery of the oil lock collar 5 and the outer periphery of the oil lock piece 4 is supplied to the reservoir chamber R3 side. The compression speed of the front fork is reduced by the throttle resistance caused by the oil flowing through the gap.

On the other hand, the throttling resistance caused by the passage of the oil through the gap causes the outer tube 1 to be held by the inner tube 2 holding the oil lock collar 5.
An oil lock chamber R is defined in the bottom portion 1a of the oil lock chamber, and further compression of the front fork is prevented by the lock pressure in the oil lock chamber R.

At this time, as shown in FIG. 3, the oil lock piece 4 rises along with the seat pipe 3 by the lock pressure in the oil lock chamber R. At this time, the oil lock piece 4 rises by an amount corresponding to the rise. , Inner tube 2
, That is, the compression stroke of the front fork is increased.

By the way, when the oil lock piece 5 rises, the cylinder 1 that rises with the oil lock piece 4
As the guide pin 10 of the adjustment pipe 6 is raised, the adjustment pipe 14 is raised, and the suspension spring 13 carried by the spring receiving portion 14a at the upper end of the adjustment pipe 14 is provided.
Of course, the lower end is raised to increase its spring force.

As described above, the conventional shock absorbing structure is formed and assembled under high precision control so that the throttle resistance between the oil lock piece 4 and the oil lock collar 5 can be exhibited as set. As compared with the case, in the shock absorbing structure according to the new proposal and the shock absorbing structure according to the present invention, even if the throttle resistance is slightly reduced, that is, the gap management for obtaining the predetermined throttle resistance is performed. Even if a high precision control is not required for the, it is possible to achieve effective shock mitigation by increasing the spring force.

Therefore, in the shock absorbing structure according to the new proposal and the shock absorbing structure according to the present invention, the oil lock piece 4 and the oil lock collar 5 are different from the conventional shock absorbing structure. This is advantageous in that a high degree of precision is not required for the accuracy control between the parts and a predetermined oil lock effect can be obtained.

Incidentally, in the shock absorbing structure according to the above-mentioned new proposal and the shock absorbing structure according to the present invention, when the front fork reverses from the most compressed state and extends, the oil lock piece 4 is attached to the seat pipe 3. Since the oil lock piece 4 can be moved up and down, the oil lock piece 4 that has been raised can quickly move down, resulting in excellent responsiveness. Therefore, the negative pressure phenomenon in the oil lock chamber R can be suppressed and the negative pressure can be reduced. The generation of the pressure noise can be suppressed, and the quick extension operation of the front fork can be realized.

Incidentally, in order to more reliably prevent the generation of the negative pressure noise at the time of reversal to the extension operation, it is preferable to provide a valve for preventing the generation of the negative pressure noise around the oil lock piece 4. preferable.

The valve is formed, for example, as shown in FIG. 4 in a so-called check valve structure. First, the valve is cut at the inner periphery of the upper end of the elevating piston 23 in the operating section 20 described above. It is assumed that a valve accommodating groove 23b having a step 23a is formed so as to be chipped.

Next, the annular leaf valve 1 is placed on the step 23a.
7 is mounted on the annular leaf valve 17, and an annular disk 18 having a small size substantially similar to the valve accommodating groove 23b and having an annular leaf valve 17 disposed on the outer periphery is mounted on the annular leaf valve 17. The disk 18 carries the oil lock piece 4.

As a result, as shown in FIG. 5, when the front fork reverses from the most compressed state and extends, the oil lock piece 4 is seated on the annular disk 18, that is, on the lifting piston 23. The lower end of the oil lock piece 4 and the lifting piston 2
Even if a gap is not formed between the upper end of the valve 3 and the upper end of the oil passage 3, the annular leaf valve 17 rises to allow the flow of the oil, and the generation of the negative pressure noise is surely suppressed. You will get.

In the shock absorbing structure according to the above-mentioned new proposal and the shock absorbing structure according to the present invention,
When the front fork reverses and expands from the most compressed state, the urging force of the suspension spring 13 finally acts on the oil lock piece 4, so that the raised oil lock piece 4 can be more quickly. It is possible to descend, and the responsiveness is further improved.

When the front fork extends with a large stroke, the upper end of the oil lock collar 5 held on the inner periphery of the lower end of the inner tube 1 comes into contact with the extension spring 9, and this extension spring 9 shrinks,
The impact at the time of maximum elongation is reduced.

The shock absorbing structure according to the new proposal and the shock absorbing structure according to the present invention include:
When the rider rides on the vehicle, that is, when the front fork expands and contracts in a so-called 1G state, it operates as follows.

That is, first, when the motorcycle runs on a flat road that is a good road, the inner tube 2
Protrudes from the outer tube 1 to contract the extension-side oil chamber R1, and oil from the extension-side oil chamber R1 passes through the orifice 3d and flows out to the reservoir chamber R3.

At this time, when the oil passes through the orifice 3 d, a damping force on the extension side is generated, and in this embodiment, between the inner circumference of the damping valve 11 and the outer circumference of the seat pipe 3. Is allowed, and a damping force on the extension side is also generated due to the gap flow.

At this time, an insufficient amount of oil in the pressure side oil chamber R2 is supplied from the reservoir chamber R3 through the through hole 3b.

Next, at the time of compression when traveling on a flat road, the inner tube 2 is immersed in the outer tube 1, and at this time, the oil shortage in the expansion oil chamber R1 is removed from the compression oil chamber R2 by the damping valve 11. And the amount of oil corresponding to the amount of immersion of the inner tube 2 is discharged from the pressure side oil chamber R2 through the through hole 3b to the reservoir chamber R3.

Then, when the oil passes through the through hole 3b, a pressure-side damping force is generated. When the damping valve 11 is opened, no damping force is generated.

[0081]

As described above, according to the present invention, both ends of the guide pin are connected to the cylinder 1 disposed between the outer periphery of the lower end of the seat pipe and the inner periphery of the oil lock piece. As a result, the oil lock piece functions as a stopper facing both ends of the guide pin, and therefore, both ends of the guide pin cannot protrude to the outer peripheral side of the oil lock piece. As a result, both ends of the guide pin A situation in which the oil lock piece projects to the outer peripheral side and interferes with the oil lock collar is not caused, and the predetermined shock absorbing function can be permanently exhibited.

Therefore, in the present invention, as compared with the case where it is necessary to take care not to project both ends of the guide pin to the outer periphery of the oil lock piece in the above-mentioned new proposal, As compared with the case where both ends of the guide pin need to be connected to the oil lock piece in a fixed state, on the condition that the cylindrical body has a large holding force in connecting both ends of the guide pin to the cylindrical body. It is advantageous in that no elaborate processing is required in forming the mounting hole in the cylindrical body,
Even if the guide pin is made of iron, the cylinder can be made of aluminum as well as the oil lock piece, so that there is no need to worry about unnecessarily increasing the weight even if the number of parts as the cylinder increases. become.

In addition to the above-mentioned new proposal, according to the present invention, when the front fork is most compressed, and when the front fork is in the vicinity of the most compression, the inner circumference of the oil lock collar and the outer circumference of the oil lock piece are not connected. The compression speed of the front fork is suppressed by the throttle resistance caused by the passage of oil through the gap formed between the front fork and the front fork due to the lock pressure in the oil lock chamber partitioned behind the oil lock piece at the time of maximum compression. Further compression will be prevented.

At this time, since the oil lock piece can be moved up and down along with the seat pipe, the oil lock piece rises by the lock pressure in the oil lock chamber. There is an advantage that the compression stroke of the front fork, that is, the compression stroke of the front fork is increased.

When the most compressed front fork is inverted and extended, the oil lock piece, which has risen along with the seat pipe, can quickly descend to have excellent responsiveness. The negative pressure phenomenon in the chamber can be suppressed, and the generation of negative pressure noise can be suppressed, and the front fork can be quickly extended.

If the front fork reaches the maximum compression state while the oil lock piece is raised by the operation of the operating portion, the oil lock piece is further raised.
As compared with the case where the oil lock piece is not raised in advance, there is an advantage that the stroke at the time of the most compression of the front fork can be increased.

The lower end is connected to the oil lock piece while carrying the lower end of a suspension spring that is vertically movably housed on the inner peripheral side of the seat pipe and urges the body side tube in the extension direction. If it is assumed that there is an adjustment pipe that is locked to the guide pin, the guide pin is also raised by raising the oil lock piece, so that the adjustment pipe is raised and the lower end of the suspension spring is raised. The spring force of the spring will be increased.

As a result, at the time of maximum compression of the front fork, the spring force of the suspension spring increases in addition to the so-called oil lock effect, so that more effective impact relaxation can be achieved.

Therefore, in the conventional shock absorbing structure,
Compared with the case where the oil lock piece is formed and assembled under high precision control so as to exhibit the throttle resistance as set between the oil lock piece and the oil lock collar, in the oil lock structure according to the present invention, Even if the throttle resistance is slightly reduced, that is, even if high precision management is not required for gap management for obtaining a predetermined throttle resistance, the spring force is increased, and as a result,
It can be said that the expected impact can be mitigated.

Therefore, in the shock absorbing structure having the above-described adjusting pipe, the oil lock piece is not required to have a higher degree of precision in the accuracy control with the oil lock collar as compared with the conventional shock absorbing structure. This is advantageous in that a predetermined oil lock effect can be obtained.

In the shock absorbing structure having the adjusting pipe, the urging force of the suspension spring acts on the oil lock piece via the adjusting pipe when the front fork reverses from the most compressed state and extends. From doing
The oil lock piece comes out of the oil lock collar more quickly, and the extension operation can be performed more quickly.

Further, in the case where the adjusting pipe has a throttle resistance portion on the outer periphery near the upper end, and the throttle resistance portion is formed in the sheet pipe so as to be located downstream of the orifice generating the extension damping force. The throttle resistance is raised along with the rise of the adjusting pipe, so that throttle resistance can be applied downstream of the orifice to increase the extension damping force generated by this orifice. become.

Therefore, when the oil lock piece is raised by the operation of the operating section, the throttle resistance rises due to the rise of the adjusting pipe accompanying the oil lock piece, and the throttle resistance is applied downstream of the orifice. As a result, the extension-side damping force at the time of the extension operation of the front fork is increased, so that more effective impact relaxation at the maximum extension can be achieved.

When the oil lock piece is lifted by operating the operating portion, the extension side damping force generated by the oil passing through the orifice when the front fork extends is increased, and the spring in the suspension spring is increased. As the force increases, the compression side damping force and the extension side damping force during expansion and contraction of the front fork, that is, the absorbed energy, can be increased to make the riding comfort in a motorcycle so-called hard. According to the invention, it is possible not only to realize the effective impact relaxation at the time of the maximum compression of the front fork in multiple stages, but also to enable the permanent exertion of the predetermined impact relaxation function,
This is ideal for expecting improvement in versatility.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing an oil lock piece side in an impact relaxation structure according to an embodiment of the present invention.

FIG. 2 is an enlarged partial longitudinal sectional view showing a state where an oil lock piece in FIG. 1 is raised by operating an operation unit.

FIG. 3 is a view showing a state in which an oil lock collar is fitted so as to cover the oil lock piece in FIG. 1, similarly to FIG. 2;

FIG. 4 is a partial longitudinal sectional view showing an oil lock piece side in a half-mounted state in an impact relaxation structure according to another embodiment.

5 is a view showing a state in which the check valve is opened under a state in which the oil lock piece in FIG. 4 is raised by operating the operation unit, similarly to FIG. 4;

FIG. 6 is a view showing a shock absorbing structure proposed prior to the present invention, similarly to FIG. 1;

FIG. 7 is a view showing a state in which the oil lock piece in FIG. 6 has been raised by the sub operation, similarly to FIG. 6;

8 is a diagram showing a state in which the oil lock case is fitted to the oil lock piece in FIG. 6 so as to cover the oil lock piece, similarly to FIG. 6;

FIG. 9 is a partial longitudinal sectional view showing a state in which an upper end side of a seat pipe is located on an inner peripheral side of a vehicle body side tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Axle side tube 1a Bottom part 1c Communication path 2 Body side tube 3 Seat pipe 3a Lower end screwing part 3b Through hole as orifice 3c Upper end enlarged diameter part 3d Orifice 3e Guide hole 4 Oil lock piece 4a Body part 4b Tapered surface 4c Oil Bore part 4d Flange 5 Oil lock collar 6 Bearing 7 Tightening nut 8 Seal 9 Extension spring 10 Guide pin 11 Damping valve 11a Annular groove 11b Notch 12 Non-return spring 13 Suspension spring 14 Adjustment pipe 14a Spring receiving part 14b Throttle resistance Part 15 Seat member 16 Cylindrical body 16a Mounting hole 17 Annular leaf valve 18 Annular disk 20 Operating part 21 Operating dial 22 Piston 23 Lifting piston 23a Step 23b Valve accommodating groove R Oil lock chamber R1 Extension oil chamber R2 Pressure oil chamber R3 Reservoir R4 oil storage chamber R5 pressure chamber

Claims (1)

[Claims] 1. A lock pressure standing in an oil lock chamber, which is disposed on the outer peripheral side of a lower end portion of a seat pipe fixedly mounted on an axle portion of an axle side tube so as to be able to ascend and descend and partitioned behind the lower end portion. The shock mitigation comprises an oil lock piece that rises at the bottom and an oil lock collar that is held on the inner circumference of the lower end of the body side tube and fits the above oil lock piece on the inner circumference when it is lowered most down. In the structure, while the oil lock piece can be moved up and down by operating the operation unit arranged at the bottom part of the axle side tube, the adjustment pipe arranged so as to be able to move up and down at the axis of the seat pipe A guide pin having both ends penetrating a vertically extending guide hole formed in the lower end of the seat pipe while supporting the lower end of the adjusting pipe at an intermediate portion. Characterized in that both ends of the guide pin are connected to a cylinder disposed between the outer periphery of the lower end of the seat pipe and the inner periphery of the oil lock piece. Construction