JP4955138B2 - Front fork - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a front fork, and more particularly to an improvement in a front fork that can increase a spring force during compression operation depending not only on a compression position but also on a compression speed.
[0002]
[Prior art and its problems]
For example, in a front fork that is mounted on the front wheel side of a motorcycle and absorbs road surface vibrations while traveling to maintain a good ride comfort, the spring force at the time of compression operation is applied only at the compression position. Some of them can be increased depending on the compression speed.
[0003]
For example, the front fork shown in FIG. 4 is set in an inverted type in which the outer tube 1 having a large diameter is a vehicle body side tube, whereas the inner tube 2 having a small diameter is an axle side tube. The accommodated suspension spring 3 urges the inner tube 2 in the extending direction so as to come out of the outer tube 1, the damper is accommodated inside, and the air spring is provided outside. Yes.
[0004]
At this time, a gas chamber G and an oil reservoir chamber (not shown) with the oil surface O as a boundary are provided on the inner peripheral side of the outer tube 1.
[0005]
On the other hand, as shown in the figure, the damper has a cylindrical gap that is a reservoir chamber R between the inner tube 2 and the inner periphery of the inner tube 2. 4, a rod 5 that is fixedly attached to the shaft core portion of the outer tube 1 and has a proximal end inserted into the cylinder 4, and is slidably received in the cylinder 4. It has a piston 6 that is connected to the base end of the rod 5 while partitioning the oil chamber R1 and the lower oil chamber R2.
[0006]
In the damper, the piston 6 allows the passage of oil between the upper oil chamber R1 and the lower oil chamber R2 to generate a predetermined expansion side damping force, and the expansion side damping valve 6a. And an extension check valve 6b in parallel with the side damping valve 6a.
[0007]
Further, in this damper, the base portion 2a which is the bottom portion of the inner tube 2 and closes the lower end of the cylinder 4 is allowed to pass oil between the reservoir chamber R and the lower oil chamber R2, and has a predetermined amount. It has a pressure side damping valve 2b that generates a pressure side damping force, and a pressure side check valve 2c in parallel with the pressure side damping valve 2b.
[0008]
The air spring is formed in a low-pressure tank structure, and has an air chamber A and an oil chamber R3 partitioned by a free piston F in the housing H. The oil chamber R3 is connected to the reservoir chamber R described above. It is supposed to be communicated.
[0009]
Incidentally, the air spring is set in a so-called separate tank structure as shown in the figure, and is distributed outside the front fork. However, considering its function, the air spring is provided in the reservoir chamber R in the damper. It is the same even if distributed.
[0010]
By the way, in this front fork, the reservoir chamber R and the oil reservoir chamber on the inner peripheral side of the outer tube 1 located above the reservoir chamber R are allowed to communicate via the control means 10. .
[0011]
Incidentally, this control means 10 is arranged in a partition wall 4a that bulges to the outer peripheral side of the upper end head portion of the cylinder 4 constituting the damper and divides the reservoir chamber R and the oil reservoir chamber. It is said.
[0012]
The control means 10 is set so as to allow the oil from the oil reservoir chamber to pass toward the reservoir chamber R at a medium to low speed but prevent the oil from passing at a high speed.
[0013]
Incidentally, the control means 10 is set so that the oil from the reservoir chamber R can pass regardless of the speed when passing toward the oil reservoir chamber.
[0014]
As a result, in the conventional front fork, a predetermined damping force is generated by the damper during the expansion / contraction operation, while a spring force is generated as follows during the compression operation. .
[0015]
That is, first, when the front fork is compressed at medium and low speeds, the oil discharged from the damper flows into the reservoir chamber R and the inner tube 2 is immersed in the outer tube 1 so that the oil level O of the oil reservoir chamber is reached. Rises, and the gas chamber G bordering on the oil level O is contracted.
[0016]
At this time, the speed of the oil flowing from the oil reservoir chamber into the reservoir chamber R through the control means 10 is slow, and therefore the resistance by the control means 10 is small, so that the pressure balance is applied to the contraction of the gas chamber G in the oil reservoir chamber. Further, the air chamber A in the reservoir chamber R is also contracted.
[0017]
Therefore, for example, when the front fork performs a compression operation at medium and low speeds when the motorcycle runs on a flat road, the riding comfort in the motorcycle can be maintained well.
[0018]
When the front fork performs a compression operation with a large stroke, the damper is greatly compressed and a high damping force is generated, while the inner tube 2 is immersed in the outer tube 1 with a large stroke, whereby the gas chamber G The air chamber A is greatly contracted while being pressure balanced, and for example, a nose dive phenomenon in a motorcycle is prevented in advance.
[0019]
Next, when the front fork is compressed at a high speed, the presence of the control means 10 causes the gas chamber G and the air chamber A to be separated.
[0020]
As a result, the air chamber A contracts with the oil discharged from the damper to increase the spring force, and the spring force at this time becomes a rod reaction force in the damper.
[0021]
On the other hand, at this time, the gas chamber G is contracted by the immersion of the inner tube 2 into the outer tube 1 to increase the spring force, and the spring force at this time becomes the tube reaction force in the front fork.
[0022]
Therefore, when the front fork is compressed at high speed, the above-mentioned rod reaction force and tube reaction force become a combined reaction force, and the front fork is compressed at high speed in cooperation with the spring force of the suspension spring 3. It becomes the reaction force when operating.
[0023]
As a result, for example, when the motorcycle lands after jumping, it is possible to prevent inadvertent sinking of the front wheels, that is, an extreme nose dive phenomenon or so-called bottoming in the front fork.
[0024]
However, in the above-described front fork, depending on the configuration of the control means 10, that is, when the control means 10 is set to orifice control, the problem is that the spring force becomes excessively high particularly during compression operation at high speed. There is.
[0025]
As a result, for example, when the front fork rides on the road surface projection when the front fork is compressing at high speed, such as when a motorcycle is traveling at high speed on wasteland, the spring force becomes extremely high. There is a risk that the steering wheel will be pushed up and the steering wheel operation will be difficult.
[0026]
The present invention was devised in view of the above-described circumstances, and the object of the invention is not to depend on the expansion / contraction position, but to increase the spring force when the compression operation is performed at high speed. Thus, it is to provide a front fork that is optimal for expecting an improvement in versatility without affecting the steering operation in a motorcycle.
[0027]
[Means for Solving the Problems]
    In order to achieve the above object, the means of the present invention includes a vehicle body side tube, an axle side tube that is slidably fitted to the vehicle body side tube, and a damper cylinder that is erected on the shaft core portion of the axle side tube. And a partition member provided at an upper end head portion of the damper cylinder and contacting an inner periphery of the axle side tube, and a piston provided with a damping valve while being suspended from the vehicle body side tube, into the damper cylinder. A rod body slidably inserted, a suspension spring interposed between the partition wall member and the vehicle body side tube to constantly urge the vehicle body side tube in the extending direction, the damper cylinder, and the axle side tube A reservoir chamber partitioned between the reservoir chamber, an air spring having a low-pressure tank structure including an oil chamber and an air chamber connected to the reservoir chamber, and the vehicle body side tube. An oil reservoir chamber separated above the reservoir chamber by a wall member, a gas chamber which is also provided on the inner peripheral side of the vehicle body side tube and is formed with the oil surface of the oil reservoir chamber as a boundary; In a front fork provided on a partition member and comprising a control means for controlling communication between the reservoir chamber and the oil reservoir chamber, the control means is formed on the partition member to connect the oil reservoir chamber and the reservoir chamber. It is composed of a communicating hole and an annular leaf valve that is openable and closable at the outlet end of the through hole on the reservoir chamber side, and the annular leaf valve is opened during the compression operation at medium and low speeds, and the oil reservoir chamber The spring force of the air chamber caused by the increase in the hydraulic pressure of the reservoir chamber is generated by the oil that flows out from the reservoir chamber to the reservoir chamber and the oil that flows out from the damper cylinder into the reservoir chamber. Also serial annular leaf valve is openedThe annular leaf valve becomes the throttle resistanceThe oil sump chamber and the aboveReservoir chamberThe air chamber spring force caused by an increase in the hydraulic pressure of the reservoir chamber that has flowed out of the damper cylinder into the reservoir chamber at this time, and the spring force of the air chamber In addition, a reaction force at the time of compression operation corresponding to a medium-low speed and a high speed synthesized by the spring force of the compressed oil gas chamber and the spring force of the suspension spring accompanying the lowering of the vehicle body side tube is obtained. It is.
[0028]
In the above-described configuration, the annular support may be formed of an elastic body so that the inner peripheral end of the annular leaf valve can be lowered when the annular leaf valve is opened.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
    Embodiments of the present invention will be described below with reference to the drawings.
  The front fork of the present invention is similar to the front fork shown in FIG. 4. The outer tube 1 is a vehicle body side tube, the inner tube 2 is an axle side tube that is slidably fitted to the outer tube 1, and the inner tube 2 is From the standing damper cylinder 4 erected on the shaft core, the annular valve seat 13 as a partition member provided on the upper end head of the damper cylinder 4 and contacting the inner periphery of the outer tube 1, and the outer tube 1 A rod body 5 slidably inserted into the damper cylinder 4 via a piston 6 having a damping valve 6 a while being suspended, and interposed between the annular valve seat 13 and the outer tube 1. A suspension spring 3 that constantly urges the outer tube 1 in the extending direction, the damper cylinder 4 and the inner A reservoir chamber R partitioned between the tube 2, an air spring having a low pressure tank structure comprising an oil chamber R 3 and an air chamber A connected to the reservoir chamber R, and the annular ring provided in the outer tube 1. An oil reservoir chamber that is separated above the reservoir chamber R by a valve seat 13 and a gas chamber that is provided on the inner peripheral side of the outer tube 1 and is formed with the oil level 0 of the oil reservoir chamber as a boundary. And a control means 10 provided on the annular valve seat 13 for controlling the communication between the reservoir chamber R and the oil reservoir chamber.
  And in this invention, the said control means 10 is formed in the said annular valve seat 13, the through-hole 13a which connects the said oil reservoir chamber and the said reservoir chamber R, and the exit end by the side of the reservoir chamber R of this through-hole 13a And an annular leaf valve 11 that can be freely opened and closed.
  Further, the annular leaf valve 11 is opened during the compression operation at medium and low speeds, and the oil flowing out from the oil reservoir chamber to the reservoir chamber R and the oil flowing out of the damper cylinder 4 into the reservoir chamber R are used as described above. Even if the spring force of the air chamber A due to the increase of the hydraulic pressure of the reservoir chamber R is generated, even if the annular leaf valve 11 is opened during the compression operation at a high speed.The annular leaf valve 11 becomes a throttle resistance.The oil sump chamber and the aboveReservoir chamber RAnd the spring force of the air chamber A caused by the increase in the hydraulic pressure of the reservoir chamber R that has flowed out of the damper cylinder 4 into the reservoir chamber R at this time is generated. A reaction force at the time of the compression operation according to the medium / low speed and the high speed synthesized by the spring force of A, the spring force of the compressed gas chamber G accompanying the lowering of the outer tube 1 and the spring force of the suspension spring 3 is obtained. Is.
Although described in detail below, the basic structure and operation are the same as those of the front fork in FIG.
[0030]
Therefore, in the illustrated embodiment, where the configuration is the same as in the case of the front fork shown in FIG. In the following, the description will focus on the features of the present invention.
[0031]
That is, first, in the front fork according to the present invention, the air chamber A is disposed in the front fork in the illustrated manner. More specifically, the air fork is provided on the outer periphery of the cylinder 4 constituting the damper. In this state, it is present in the reservoir chamber R.
[0032]
At this time, the air chamber A is composed of a bellows 21 which is an elastic body having a predetermined mechanical strength and abundant elasticity, and the upper and lower ends of the bellows 21 are fastened to the outer periphery of the cylinder 4 constituting the damper. As a result, it is assumed that it is arranged so as to surround the cylinder 4, that is, the outer periphery of the damper.
[0033]
The air chamber A may be formed in a mode in which the bellows is fixed to the inner periphery of the inner tube 2 although not illustrated, considering the function thereof, instead of the illustrated one. As long as it does not interfere with the control means 10 which will be described later, it may be accommodated in the reservoir chamber R in a floating state while being formed in an independent shrinkable bag shape. Further, as in the case of the conventional example described above. Alternatively, a separate tank structure may be set and distributed outside the front fork.
[0034]
By the way, when the gas chamber G formed on the inner peripheral side of the outer tube 1 constituting the front fork with the oil surface O as a boundary is compared with the above-described air chamber A, the gas chamber is in volume. G is set to be larger than the air chamber A. For example, when the front fork is fully extended, the volume of the air chamber A is 60 cc, whereas the volume of the gas chamber G is 1000 cc. At this time, the pressure in the air chamber A and the gas chamber G is 98 KPa (kilopascal).
[0035]
By the way, the cross-sectional area of the rod 5 constituting the damper is 1 cm.²When the pressure receiving area on the inner tube 2 side (indicated by the symbol D in FIG. 1) is 10 cm, excluding the cross-sectional area of the rod 5.²It is set to become.
[0036]
In addition, as shown in the figure, the damper discharges an amount of oil corresponding to the intrusion volume integral of the rod 5 into the reservoir chamber R through the hole 4b (see FIG. 2) opened in the cylinder 4 during the compression operation, and extends. An amount of oil corresponding to the withdrawal volume of the rod 5 during operation is set to be sucked from the reservoir chamber R through the hole 4b.
[0037]
Next, as shown in the figure, the control means 10 is configured so that the outer periphery of the cylindrical body 7 connected upward to the upper end of the cylinder 4 constituting the damper and the outer periphery of the cylindrical body 7 face each other. It is positioned between the inner periphery and is arranged so as to divide the upper oil reservoir chamber and the lower reservoir chamber R.
[0038]
That is, as shown in FIG. 3, the control means 10 has an annular leaf valve 11 having an outer peripheral side end as a bent end in a state of being interposed on the outer periphery of the upper end head portion in the cylinder 4 constituting the damper. In addition, the inner peripheral side end on the back side of the annular leaf valve 11 is carried by the annular support 12 interposed on the outer periphery of the upper end head portion.
[0039]
The annular leaf valve 11 is also interposed in the outer periphery of the upper end head portion of the cylinder 4, and the outer periphery of the annular leaf valve 11 is in sliding contact with a slight gap (not shown) serving as a passage on the inner periphery of the inner tube 2. The valve seat member 13 is adjacent to the lower end surface.
[0040]
At this time, the annular leaf valve 11 is pierced into the annular valve seat member 13 with the outer peripheral side end being a bent end on the lower end surface of the annular valve seat member 13 and the inner peripheral side end being a fixed side end, and an oil sump is formed. The downstream end of the through hole 13a allowing the communication between the chamber and the reservoir chamber R is disposed so as to be openable and closable.
[0041]
The annular support 12 is locked to a step portion (not shown) formed with a flange 4 c on the outer periphery of the upper end of the cylinder 4, and the annular valve seat member 13 is a lower end of the cylindrical body 7. It is supposed that it is fixed at a predetermined position by a fixing nut 14 screwed into a thread 7a formed on the outer periphery of the side.
[0042]
An annular spring seat 15 is placed on the upper end of the annular valve seat member 13 so as not to close the upstream end of the port 13a. The suspension spring 3 is placed on the upper end of the annular spring seat 15. It is supposed that the lower end of is locked.
[0043]
Incidentally, from this point of view, the annular valve seat member 13 is fixed at a predetermined position by the urging force of the suspension spring 3, so that the fixing of the annular valve seat member 13 at the predetermined position is performed as described above. It can be said that the nut 14 is unnecessary, and further, it is not necessary to form the thread 7a on the outer periphery on the lower end side of the cylindrical body 7.
[0044]
In addition, when the annular valve seat member 13 is fixed without using the fixing nut 14, the annular valve seat member 13 can be easily removed. Therefore, the annular leaf valve 11 is bent and has different rigidity. Therefore, it is advantageous in that the valve characteristics obtained with the annular leaf valve 11 can be arbitrarily selected.
[0045]
In addition, a concave groove 13b that opens laterally, that is, toward the inner periphery of the inner tube 2, is formed on the outer periphery of the annular valve seat member 13, and is formed annularly in the concave groove 13b. In addition, the check valve 16 is arranged in a state having an appropriate interval (not shown) serving as a passage between the check groove 16 and a so-called inner bottom in the concave groove 13b while being movable in the vertical direction.
[0046]
Further, when the check valve 16 is in the state shown in the drawing, that is, when the check valve 16 is descending in the concave groove 13b, the oil from the oil reservoir chamber flows out into the reservoir chamber R through the concave groove 13b. It is supposed to prevent that.
[0047]
Although not shown, the check valve 16 allows the oil from the reservoir chamber R to return to the oil sump chamber through the recess groove 13b as a passage when rising in the recess groove 13b. It is said.
[0048]
The cylinder 7 described above is illustrated as an oil lock case that constitutes an oil lock structure that operates when the front fork is compressed most, and the cylinder 7 that is the oil lock case has an inner peripheral side. In many cases, the oil lock piece 8 that is held in a fixed state is inserted into the tip end side that is the upper end of the rod 5 that constitutes the damper so as to be able to appear and retract (see a virtual diagram in FIG. 1).
[0049]
Therefore, the control means 10 allows the oil in the oil sump chamber to open the annular leaf valve 11 and flow out into the reservoir chamber R when the front fork is compressed at medium and low speeds. become.
[0050]
  On the other hand, in the control means 10, when the front fork is compressed at high speed, the oil in the oil sump chamber cannot sufficiently flow into the reservoir chamber R even if the annular leaf valve 11 is opened. That is, the control means 10 communicates between the oil reservoir chamber and the reservoir chamber R.InadequateIt will be.
[0051]
At this time, in the present invention, since the outer peripheral end of the annular leaf valve 11 is bent to generate a so-called flow resistance, the flow resistance is reduced as compared with the case where the flow resistance is generated by the restriction by the orifice. A sudden rise can be prevented.
[0052]
Note that, in the case where pressure accumulation is induced in the reservoir chamber R due to repeated large stroke compression operations in an extremely short time, the reservoir chamber R side becomes the high pressure side regardless of the speed. Occasionally, the check valve 16 rises and the accumulated pressure in the reservoir chamber R is released to the oil reservoir chamber.
[0053]
In the front fork formed as described above, the damping force can be generated by the damper during the expansion / contraction operation, and the following operation is performed according to the speed during the compression operation.
[0054]
  That is, first, when the front fork is compressed at a high speed, it cannot be left to the expectation that oil from the oil sump chamber flows out to the reservoir chamber R through the control means 10, and therefore, the control means 10 is said to have a throttle resistance. Oil sump chamberAnd the reservoir chamber R are not sufficiently connected.
[0055]
As a result, the air chamber A disposed in the reservoir chamber R contracts only by the outflow of the oil discharged from the damper that performs the compression operation to the reservoir chamber R, that is, only by the increase of the hydraulic pressure in the reservoir chamber R. The spring force is increased, and the spring force at this time becomes the rod reaction force in the damper.
[0056]
On the other hand, the gas chamber G between the oil reservoir chamber and the oil level O is contracted only by the immersion of the inner tube 2 into the outer tube 1, that is, only when the oil level O rises, and the spring force is increased. The spring force at this time becomes the tube reaction force in the front fork.
[0057]
As a result, when the front fork is compressed at a high speed, the rod reaction force and the tube reaction force described above are combined, and the front fork is compressed in cooperation with the spring force of the suspension spring 3. It becomes a reaction force when.
[0058]
By the way, the rod reaction force and the tube reaction force are as follows.
[0059]
  That is, when the front fork is compressed at high speed, the throttle resistance of the control means 10 is large and the gas chamber G and the air chamber ACommunication becomes insufficientTherefore, when it is assumed that the volume of the gas chamber G is changed from 1000 cc to 100 cc and the volume of the air chamber A is changed from 60 cc to 30 cc, the compression ratio in the gas chamber G is 1000 cc / 100 cc = 10. The compression ratio in A is 60 cc / 30 cc = 2.
[0060]
Therefore, the above tube reaction force is
10cm²× 10 × 98KPa = 980N (Newton)
The above rod reaction force is
1cm²× 2 × 98KPa = 19.6N
The total 999.6 N becomes a reaction force that cooperates with the spring force of the suspension spring 3.
[0061]
Next, when the front fork is compressed at medium and low speeds, the oil discharged from the damper that is compressed flows out into the reservoir chamber R and the inner tube 2 is immersed in the outer tube 1 so that the oil level O rises. Then, the gas chamber G with the oil level O as a boundary is contracted.
[0062]
At this time, the speed at which the oil from the oil reservoir chamber flows out into the reservoir chamber is also slow, and therefore the throttle resistance in the control means 10 is small, so that the air chamber A is also contracted so as to balance the contraction of the gas chamber G. .
[0063]
And the reaction force which is a spring force at this time is as follows.
[0064]
That is, when the front fork is compressed at medium and low speeds, the throttle resistance of the control means 10 is small, so the gas chamber G and the air chamber A are pressure balanced and contracted, and the compression ratio is
(1000cc + 60cc) / (100cc + 30cc) ≈8.2,
Therefore, the reaction force at this time is
(10cm²+ 1cm²) × 8.2 × 98 KPa = 883.96 N
This reaction force becomes a reaction force that cooperates with the spring force of the suspension spring 3.
[0065]
From the above, when the front fork is compressed at a high speed, a higher reaction force, that is, a spring force, is generated compared to when the front fork is compressed at a medium speed.
[0066]
As a result, when the motorcycle on which this front fork is mounted normally travels on a flat road, it absorbs road vibration and maintains a comfortable ride on the motorcycle, while operating a sudden brake, etc. When the nose dive phenomenon is caused, the vehicle body posture can be properly maintained by the high spring force.
[0067]
Also, for example, when a motorcycle rides on a road projection when driving at a high speed on a bad road, or landing after jumping, a mischievous front wheel side sinking, that is, an extreme nose dive phenomenon or a so-called front fork It will be possible to prevent the bottoming in advance.
[0068]
In this front fork, it is a temporary situation that the spring force becomes high in order to maintain the body posture of the motorcycle properly. Therefore, the so-called internal pressure does not increase continuously. This will not degrade the ride comfort, but will not reduce the durability of the seal.
[0069]
By the way, as described above, the annular support 12 is formed of a rigid body, and the inner peripheral side end of the annular leaf valve 11 is sandwiched between the inner peripheral side end of the annular valve seat member 13 in a fixed state. However, instead of this, the annular support 13 may be formed of an elastic body such as rubber so that the inner peripheral side end of the annular leaf valve 11 can be lowered.
[0070]
In such a setting, even if the front fork is compressed at the same speed, the valve characteristic is changed depending on the position, that is, the inclination degree or the like is changed in the linear shape for displaying the valve characteristic. This is advantageous in that it becomes possible.
[0071]
In the above description, the front fork is set upside down. However, the front fork may be set upright such that the outer tube 1 is an axle side tube and the inner tube 2 is a body side tube. Of course, the same effect as described above can be expected.
[0072]
【The invention's effect】
As described above, according to the present invention, a damping force is generated by the damper when the front fork is extended and contracted, while not only depending on the compression position but also the compression speed when the front fork is compressed. In addition, it is possible to obtain a spring force as a predetermined reaction force, and in particular, since the spring force is not increased unnecessarily during high-speed compression operation, for example, when a motorcycle is traveling on a rough road at a high speed. When landing after jumping on a road surface protrusion or jumping, it is possible to prevent inadvertent sinking of the front wheel side, that is, extreme nose dive phenomenon or so-called bottoming in the front fork.
[0073]
At this time, the above-described situation where the spring force is increased is a temporary situation, and therefore, the so-called internal pressure is not continuously increased, and therefore, the ride comfort is not deteriorated. In addition, there is no fear of reducing the durability of the seal.
[0074]
Further, in the present invention, when the annular support carrying the inner peripheral side end of the annular leaf valve is formed of an elastic body such as rubber, the inner peripheral side end of the annular leaf valve can be lowered. Even if the front fork is compressed at the same speed, it is advantageous in that the valve characteristic can be changed depending on the position, that is, the inclination degree or the like can be changed in the linear shape for displaying the valve characteristic.
[0075]
In the present invention, it is assumed that the annular valve seat member that makes the annular leaf valve adjacent to the lower end surface is fixed at a predetermined position by the urging force of the suspension spring without screwing the fixing nut. In this case, a fixing nut is not required for fixing the annular valve seat member to a predetermined position, and further, it is not necessary to form a thread on the outer periphery on the lower end side of the cylindrical body in order to screw the fixing nut. Is advantageous.
[0076]
As well as fixing the annular valve seat member without using a fixing nut, it becomes easy to remove the annular valve seat member, and therefore the annular leaf valve can be easily converted into one with different flexural rigidity. Therefore, it is advantageous in that the valve characteristics obtained with the annular leaf valve can be arbitrarily selected.
[0077]
As a result, according to the present invention, not only depends on the expansion / contraction position, but also the spring force when the compression operation is performed at a high speed should not be unnecessarily increased so as not to affect the steering operation in the motorcycle. Ideal for expecting improved versatility.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal sectional view showing an intermediate portion of a front fork according to the present invention.
FIG. 2 is a partial longitudinal sectional view showing a lower end portion of a front fork according to the present invention.
FIG. 3 is a partial cross-sectional view showing an enlarged control means portion in FIG. 1;
FIG. 4 is a longitudinal sectional view showing in principle a front fork as a conventional example.
[Explanation of symbols]
1 Outer tube
2 Inner tube
2a Base part
2b Pressure side damping valve
2c Pressure check valve
3 Suspension spring
4 Cylinders constituting the damper
4a Bulkhead
4b hole
5 Rod constituting the damper
6 Piston constituting the damper
6a Extension side damping valve
6b Extension side check valve
7 cylinder
7a inner space
8 Oil lock piece
10 Control means
11 Annular leaf valve
12 Ring support
13 Annular valve seat member
13a through hole
14 Fixing nut
15 Annular spring seat
16 Check valve
16a Notch
21 Bellows
22 Tightening band
A air chamber
G gas chamber
O Oil level
R Reservoir chamber
R1 Upper oil chamber
R2 Lower oil chamber

Claims (1)

A vehicle body side tube, an axle side tube that is slidably fitted to the vehicle body side tube, a damper cylinder standing on the shaft core portion of the axle side tube, and an upper end head portion of the damper cylinder. A partition member abutting on the inner periphery of the axle side tube, a rod body slidably inserted into the damper cylinder through a piston provided with a damping valve while being suspended from the vehicle body side tube, and the partition member; A suspension spring interposed between the vehicle body side tube and constantly urging the vehicle body side tube in the extending direction; a reservoir chamber defined between the damper cylinder and the axle side tube; and the reservoir chamber. An air spring having a low-pressure tank structure including an oil chamber and an air chamber connected to each other, and an oil reservoir provided in the vehicle body side tube and separated above the reservoir chamber by the partition member A gas chamber formed on the inner circumferential side of the vehicle body side tube and bordering on the oil surface of the oil reservoir chamber, and a reservoir chamber and the oil reservoir chamber provided in the partition member. In the front fork comprising a control means for controlling the communication between the oil reservoir and the reservoir chamber, the control means is formed in the partition member, and an outlet of the through hole on the reservoir chamber side. The annular leaf valve is provided at the end so as to be openable and closable. The annular leaf valve is opened during a compression operation at medium and low speeds, and the oil that has flowed from the oil reservoir chamber into the reservoir chamber and the damper cylinder from above. while generating the spring force of the air chamber by the oil spilled into the reservoir chamber caused by the oil pressure increase in the reservoir chamber, the annular Lee be opened is the annular leaf valve during compression operation at a high speed Valve becomes the throttle resistance is insufficient communication between the oil reservoir chamber and the reservoir chamber, the air chamber due to the pressure increase in the reservoir chamber flows into the reservoir chamber from the time within the damper cylinder The spring force of the air chamber, the compressed spring force of the gas chamber accompanying the lowering of the vehicle body side tube, and the spring force of the suspension spring are combined according to the medium low speed and the high speed. Front fork characterized by obtaining reaction force during compression operation.

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