JPH10119868A - Front wheel suspension device for motorcycle and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower costs while operation stability is being kept excellent. SOLUTION: In the front wheel suspension device for a motorcycle, which is so constituted that a right and a left front fork 2 and 3 can be pivotally supported by a car body by way of an under bracket 4, concurrently a front wheel is rotatably supported in such a way as to be freely revolved, and the respective front forks allow each damping device 14 provided with a piston valve mechanism 26 producing damping force and a base valve mechanism 27 to be housed inside each inner tube 12 movingly fitted into each outer tube 11, the damper device of one front fork 2 furthermore possesses an extension side damping force producing adjustment device 29 producing extension side damping force capable of being adjusted by an external operation by an extension side operation part 28, and the damper device of the other front fork 3 furthermore possesses a pressing side damping force producing adjustment device 87 producing pressing side damping force capable of being adjusted by an external operation by a pressing side operation part 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel suspension device for a motorcycle or the like for suspending a front wheel of a motorcycle or the like.

[0002]

2. Description of the Related Art In a front fork assembly as a front wheel suspension device for a motorcycle or the like, left and right front forks are pivotally supported on a vehicle body via a steering bracket.
The front wheels are rotatably supported by these two front forks so that the front wheels can be steered.

[0003] Each of the above-mentioned front forks has the same structure in general, a body side tube and a wheel side tube are slidably fitted, and a suspension spring and a damper device are housed in both tubes. .

The damper device has the same structure in the left and right front forks, and includes an extension-side damping force generator, a compression-side damping force generator, and an extension-side damping force generating an extension-side damping force adjustable by an external operation. There is an apparatus having an adjustment device and a compression-side damping force generation adjusting device that generates a compression-side damping force that can be adjusted by an external operation (first related art).

In addition, as described in Japanese Utility Model Publication No. 49-1162, a front fork assembly is provided with only a damper device without disposing a suspension spring on one of the left and right front forks. There is an arrangement in which only a suspension spring is arranged on the other front fork and a damper device is not arranged (second prior art).

Further, as described in Japanese Utility Model Publication No. 51-41720, a suspension spring and a damper device are arranged on only one of the left and right front forks, and the other front fork is mounted on the front fork assembly. There is one in which a suspension spring and a damper device are not disposed (third conventional technique).

[0007]

In the first prior art, since one extension-side damping force generation adjusting device and one compression-side damping force generation adjusting device are disposed on each of the left and right front forks, a high cost structure is required. It is.

In the second prior art, only the suspension spring is disposed on one of the left and right front forks, and only the damper mechanism is disposed on the other. Therefore, although the cost is low, the imbalance between the left and right front forks is low. Violently, steering stability is reduced.

Further, in the third prior art, only one of the front forks is provided with a damper mechanism for generating a damping force and a suspension spring, and the other front fork is formed as a simple guide cylinder. Large imbalance in front fork suspension characteristics.

An object of the present invention is to provide a front wheel suspension device for a motorcycle or the like, which can reduce costs while ensuring good steering stability.

[0011]

According to the present invention, the left and right front forks can be pivotally supported on a vehicle body via a steering bracket, and the front wheels are rotatably pivotally supported. The fork includes a body-side tube supported by the steering bracket, a wheel-side tube pivotally supporting the front wheel and slidably fitted to the body-side tube, and damped by being housed in both tubes. A damper device having a damping force generating device that generates a force, and a front wheel suspension device such as a motorcycle configured to include: a damper device of one of the front forks, wherein An extension-side damping force generation adjusting device that allows the extension-side damping force to be adjusted by an external operation of the extension-side operation mechanism disposed at the upper end of the tube. The other damper device of the front fork has a compression side in which the compression side damping force can be adjusted by an external operation of a compression side operation mechanism disposed at an upper end of the vehicle body side tube of the other front fork. This has a damping force generation adjusting device.

According to a second aspect of the present invention, in the first aspect of the present invention, the damper device of the one front fork is provided with a damper cylinder which is erected on a wheel side tube and fills the inside with hydraulic oil. A hollow rod slidably disposed in the damper cylinder via a piston and having an upper end attached to the vehicle body side tube, a piston upper chamber and a piston in the damper cylinder partitioned by the piston A damping force generating device for generating a damping force by hydraulic oil flowing between the lower chamber and the oil sump chamber formed outside the damper cylinder; and a damping force generator arranged in the rod, the piston upper chamber and the oil The flow path in the rod communicating with the storage chamber can be changed by an extension-side operation mechanism arranged at the upper end of the body-side tube. And the extension side damping force generating adjusting device for adjustable side damping force generated by the extension stroke of over click, and has a.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described in the above, the damper device of the other front fork is provided upright on a wheel-side tube and filled with hydraulic oil therein, and slidably disposed in the damper cylinder via a piston. A hollow rod whose upper end is attached to the body side tube,
A damping force generating device for generating a damping force by a hydraulic oil flowing between each of an upper piston chamber and a lower piston chamber in the damper cylinder partitioned by the piston and an oil reservoir formed outside the damper cylinder; The flow passage in the rod, which is provided in the rod and communicates the lower piston chamber and the oil reservoir, can be changed by a pressure-side operation mechanism disposed at an upper end of the body-side tube. And a pressure-side damping force generation adjusting device capable of adjusting a pressure-side damping force generated in the pressure-side stroke of the front fork on the road.

[0014] The invention according to claim 4 is the invention according to claim 1 or 3.
In the invention described in (1), the damper device of the one front fork is provided upright on a wheel side tube and filled with hydraulic oil therein, and is slidably disposed in the damper cylinder via a piston. A hollow rod whose upper end is attached to the body side tube,
A damping force generating device for generating a damping force by a hydraulic oil flowing between each of an upper piston chamber and a lower piston chamber in the damper cylinder partitioned by the piston and an oil reservoir formed outside the damper cylinder; The flow path in the rod, which is disposed in the rod and communicates the upper piston chamber and the lower piston chamber, can be changed by an extension-side operation mechanism disposed at an upper end portion of the body-side tube, An extension side damping force generation adjusting device capable of adjusting the extension side damping force generated in the extension side stroke of the front fork in the flow path.

The first to fourth aspects of the present invention have the following effects. On one front fork, an extension side damping force generation adjustment device that generates an adjustable extension side damping force is installed,
There is no pressure side damping force generation adjustment device that generates an adjustable pressure side damping force, and the other front fork has
A compression damping force generation adjustment device that generates an adjustable compression damping force is installed, and no expansion damping force generation adjustment device that generates an adjustable expansion damping force is installed. The damping force generation adjusting device and the extension side damping force generation adjusting device can be reduced one by one. For this reason, the cost of the entire left and right front forks, that is, the cost of the front wheel suspension device of the motorcycle can be reduced.

The extension-side damping force of the front fork in the extension stroke is adjusted by an extension-side damping force generation adjusting device of one front fork, and the compression-side damping force of the front fork in the compression stroke is adjusted by the other front fork. Since it is adjusted by the compression side damping force generation adjustment device, the expansion side damping force generated by the left and right front forks during the extension process of the front fork is different, and is generated by the left and right front forks during the compression process of the front fork. Pressure side damping force is different. However, the respective differences between the extension side damping forces and the compression side damping forces are within the adjustment range of the damping force and are small. Therefore, even if a difference occurs between the left and right front forks in, for example, the extension side damping force (or the compression side damping force), the balance between the left and right front forks is not adversely affected, and the stability of the steering of the motorcycle is ensured satisfactorily. be able to.

Further, an extension side operation mechanism for operating the extension side damping force generation adjusting device installed on one of the front forks,
The pressure-side operating mechanism that operates the pressure-side damping force generation adjustment device installed on the other front fork is also located at the upper end of the body-side tube of each front fork, so that the rider riding a motorcycle etc. The operation mechanism can be easily operated, and good operability can be secured.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. [A] First Embodiment FIG. 1 is an overall front view of a front fork assembly showing a first embodiment of a front wheel suspension device for a motorcycle or the like according to the present invention. FIG. 2 is a half sectional view showing one of the front forks in FIG. FIG. 3 is a side sectional view showing the periphery of the piston and the rod of FIG. FIG.
FIG. 3 is a half-side sectional view showing an upper end portion of FIG. FIG. 5 is a view on arrow V in FIG. FIG. 6 is a side sectional view showing the periphery of the base piston in FIG. FIG. 7 is a half sectional view showing the other front fork of FIG. FIG. 8 is a side sectional view showing the periphery of the piston and the rod of FIG. FIG. 9 shows FIG.
FIG. 3 is a half-side sectional view showing an upper end portion of FIG. FIG. 10 shows the X in FIG.
It is an arrow view.

(1) Overall Configuration (FIG. 1) As shown in FIG. 1, a front fork assembly 1 as a front wheel suspension device for a motorcycle or the like for suspending a front wheel of a motorcycle includes one upright front fork 2 and one upright type front fork 2. The other upright front fork 3 and the inner tube 12 as the vehicle body side tube are connected to the under bracket 4 and the upper bracket 5 as the steering bracket (FIG. 2,
7), the front fork 2 and the other front fork 3 hold the outer tube 11 as a wheel-side tube.
A front wheel (not shown) is rotatably supported, and a steering shaft 6 disposed at the center of each of the under bracket 4 and the upper bracket 5 is pivotally supported on a head pipe (both not shown) of the vehicle body frame. Steering is enabled.

(2) One front fork (FIGS. 2 to 6) As shown in FIG. 2, one front fork 2 has an inner tube 12 inserted into an outer tube 11 and a space between the two tubes 11 and 12. The suspension tube 13 includes a suspension spring 13 and a damper device 14 therein. As described above, the inner tube 12 is supported on the vehicle body side, and the outer tube 11 supports the front wheel. One front fork 2 shown in FIG. 2 shows the most compression stroke state.

A first inner tube is provided on the inner periphery of the open end of the outer tube 11.
The guide bush 16 is provided with a second guide bush 17 on the outer periphery of the lower end portion of the inner tube 12. The first guide bush 16 is in sliding contact with the outer peripheral surface of the inner tube 12, and the second guide bush 17 is
The outer tube 11 and the inner tube 12 are configured to be slidable by sliding contact with the inner peripheral surface of the inner tube.

The lower end of the suspension spring 13 is supported by the outer tube 11 via a lower spring seat 18 and a seat guide 19, and a damper cylinder 25 and a center bolt 30, which will be described later. In addition, suspension spring 1
The upper end of 3 is supported by the inner tube 12 via the upper spring seat 21 and the fork cap 24. The suspension spring 13 absorbs the impact force from the road surface.

As shown in FIG. 4, the fork cap 24 is screwed and fixed to the upper end of the inner tube 12 to close the upper end of the inner tube 12. A hollow joint bolt 23 is screwed and fixed to the fork cap 24, and an upper end portion of a piston rod 34 described later is screwed and fixed to the joint bolt 23. Lock nut 2
Numeral 2 is screwed to the upper end of the piston rod 34 and abuts on the joint bolt 23 to perform a function of preventing the piston rod 34 from loosening the joint bolt 23.

The damper device 14 is provided with the outer tube 1
1, a damper cylinder 25, a piston valve mechanism 26 as an extension-side damping force generator for generating an extension-side damping force, and a base valve mechanism 27 as a compression-side damping force generator for generating a compression-side damping force. And an extension-side damping force generation adjusting device 29 that can adjust the extension-side damping force by an external operation of the extension-side operation unit 28 as the extension-side operation mechanism. The damping force generated by the piston valve mechanism 26, the base valve mechanism 27, and the extension-side damping force generation adjusting device 29 causes the outer tube 11 and the in-tube 12 to expand and contract due to shock absorption by the suspension spring 13. Is suppressed.

The inner periphery of the lower end of the damper cylinder 25 is screwed to a center bolt 30, and the center bolt 30 is fixed to the bottom of the outer tube 11, so that the damper cylinder 25 stands upright on the outer tube 11. A reservoir chamber 31 as an oil reservoir is formed by being surrounded by the damper cylinder 25, the outer tube 11, and the inner tube 12. A communication hole 32 is formed in a lower portion of the damper cylinder 25, and the inside of the damper cylinder 25 (the base valve chamber 45C) and the reservoir chamber 31 communicate with each other through the communication hole 32.

The hydraulic oil is filled in the damper cylinder 25 and further stored in the reservoir chamber 31 at the central part and the lower part except the upper part. In the figure, the symbol H indicates the oil level of the hydraulic oil. The upper part of the reservoir chamber 31 is filled with gas (for example, air). When the pressure of this gas is accumulated during operation and rises, the plug bolt 2 attached to the fork cap 24
With 0, the pressure is reduced.

As shown in FIG. 3, the piston valve mechanism 26 has a piston 33, a piston rod 34, a sax valve 35, a square hole 36 formed in the piston 33, and a poppet valve 37.

The piston rod 34 has a hollow shape, and a hollow piston holder 38 is screwed around the inner periphery of the lower end. A piston valve stopper 39, a valve guide 40, a valve collar 41, and a piston 33 are sequentially fitted to the piston holder 38, and these are fastened by nuts 42 and attached to the piston holder 38. The upper end of the piston rod 34 is attached to the inner tube 12 via the joint bolt 23 and the fork cap 24 as described above.

A piston ring 43 is mounted on the outer periphery of the piston 33, and a piston holder 38 and a damper cylinder 25 are slidably provided. The piston 33 has a piston flow path 4 around a piston holder 38.
4 are formed therethrough. Further, the inside of the damper cylinder 25 is partitioned into an upper piston chamber 45A and a lower piston chamber 45B by the piston 33.

The sax valve 35 includes a disk valve 46, a valve presser 47, a valve spring 48, and a valve guide 40. Valve retainer 47
Is slidable on the outer periphery of the valve collar 41 against the spring force of the valve spring 48. Valve retainer 4
7, a valve channel 49 is formed to pass therethrough. The disc valve 46 is installed on the end face of the valve presser 47 on the side of the piston 33 so that the valve channel 49 can be closed.

When the relative speed of the piston 33 with respect to the damper cylinder 25 is medium or high during the compression stroke of the front fork 2, the Sachs valve 35 causes the valve presser 47 and the disc valve 46 to operate the piston flow path 44.
It is pressed against the spring force of the valve spring 48 by the hydraulic oil in the piston lower chamber 45B flowing through the inside,
This hydraulic oil is guided from the opening 50 of the valve guide 40 into the upper piston chamber 45A, and the negative pressure in the upper piston chamber 45A is eliminated.

The sax valve 35 moves the damper cylinder 25 during the extension stroke of the front fork 2.
When the relative speed of the piston 33 is medium to high, the inner peripheral side of the disc valve 46 bends and deforms due to the hydraulic oil in the piston upper chamber 45A flowing through the valve flow path 49 of the valve presser 47, and the damping at the medium side of the extension side is high. Generate power,
This hydraulic oil is supplied to the lower piston chamber 45 through the piston flow path 44.
Flow into B.

The square hole 36 is formed in the piston 33 so that the outer periphery of the piston 33 communicates with the piston flow path 44. When the relative speed of the piston 33 with respect to the damper cylinder 25 is low during the compression stroke of the front fork 2, the square hole 36 allows the hydraulic oil in the lower piston chamber 45 </ b> B to flow into the upper piston chamber 45 </ b> A. The negative pressure in the upper chamber 45A is eliminated. In addition, when the relative speed of the piston 33 with respect to the damper cylinder 25 is low during the extension stroke of the front fork 2, the square hole 36 allows the hydraulic oil in the upper piston chamber 45 </ b> A to pass through the piston flow path 44 and move downward through the piston flow path 44. It flows into the chamber 45B, during which a damping force is generated at the time of low speed on the extension side.

The poppet valve 37 is provided in a hollow portion 38A of a piston holder 38 so as to be movable in the axial direction of the piston holder 38, and is provided in a direction perpendicular to the axis of the piston holder 38. The flow path 51 can be opened and closed. That is, the poppet valve 37 has a closed cylindrical shape, and is configured to be able to be seated or unseated on the cylindrical valve seat 52 provided inside the piston holder 38. In the compression stroke of the front fork 2, the poppet valve 37 is seated on the valve seat 52 and closed by the pressure of the hydraulic oil in the lower piston chamber 45 </ b> B, thereby shutting off the holder flow path 51. In the extension stroke of the front fork 2, the poppet valve 37 is separated from the valve seat 52 and opened by the pressure of the hydraulic oil in the piston upper chamber 45 </ b> A, and the holder flow path 51 is brought into a communicating state, and the piston The hydraulic oil in the upper chamber 45A is supplied to the hollow portion 3 of the piston rod 34.
Lead into 4A.

As shown in FIG. 6, the base valve mechanism 27 includes a base piston 53, a sax valve 54, and a square hole 55.

Base piston 53, valve collar 56,
The valve guide 57 and the valve stopper 58 are sequentially fitted to the center bolt 30, and these are fastened by the nut 59 and attached to the center bolt 30. The center bolt 30 is connected to the outer tube 1 as shown in FIG.
1 is fastened to the bottom.

The base piston 53 has a base piston passage 60 formed therethrough around the center bolt 30. Further, the base piston 53 forms a base valve chamber 45C which is divided into a piston lower chamber 45B.

The sax valve 54 includes a disk valve 61, a valve presser 62, a valve spring 63, and a valve guide 57. Valve retainer 62
Is slidable on the outer periphery of the valve collar 56 against the spring force of the valve spring 63. Valve retainer 6
2, a valve channel 64 is formed to penetrate therethrough. The disc valve 61 is installed on the end face of the valve retainer 62 on the side of the base piston 53 so that the valve flow path 64 can be closed.

In the compression stroke of one of the front forks 2, when the relative speed of the piston 33 with respect to the damper cylinder 25 is medium or high, the Sachs valve 54 has a volume equivalent to the volume of the piston rod 34 entering the damper cylinder 25. When the hydraulic oil reaches the valve flow path 64 of the valve retainer 62 through the opening 65 of the valve guide 57, the hydraulic oil causes the inner peripheral side of the disc valve 61 to bend and deform.
Generates a high-speed damping force on the compression side. The hydraulic oil that has deformed and deformed the disk valve 61 reaches the base valve chamber 45C via the base piston flow path 60 of the base piston 53,
It flows into the reservoir chamber 31 from the communication hole 32 of the damper cylinder 25.

In the extension stroke of the front fork 2, when the relative speed of the piston 33 with respect to the damper cylinder 25 is a medium speed, the Sachs valve 54 operates by an amount corresponding to the volume of the piston rod 34 withdrawn from the damper cylinder 25. When the oil reaches the base piston flow path 60 from the reservoir chamber 31 via the communication hole 32 and the base valve chamber 45C, the hydraulic oil presses the disc valve 61 and the valve presser 62 against the spring force of the valve spring 63. Then, the hydraulic oil is guided from the opening 65 of the valve guide 57 into the lower piston chamber 45B, and the negative pressure in the lower piston chamber 45B is released.

The square hole 55 is formed in the base piston 53 so that the outer periphery of the base piston 53 communicates with the base piston flow path 60. This square hole 5
5 is a compression stroke of one of the front forks 2. When the relative speed of the piston 33 with respect to the damper cylinder 25 is low, hydraulic oil equivalent to the volume of the piston rod 34 entering the damper cylinder 25 is provided in the lower piston chamber. 45B, a damping force is generated at the time of low pressure side, and this hydraulic oil is supplied to the base piston flow path 60 and the base valve chamber 45C.
And, it leads to the reservoir chamber 31 through the communication hole 32.

Further, when the relative speed of the piston 33 with respect to the damper cylinder 25 is low during the extension stroke of the front fork 2, the square hole 55 has a volume equivalent to the volume of the piston rod 34 withdrawing from the damper cylinder 25. Is introduced into the lower piston chamber 45B from the reservoir chamber 31 through the communication hole 32, the base valve chamber 45C and the base piston flow path 60, and the negative pressure in the lower piston chamber 45B is eliminated.

The extension-side damping force generation adjusting device 29 is shown in FIG.
As shown in FIG. 5, a valve seat 66 screwed and fixed to the inner periphery of the upper end of the piston rod 34, and an extension needle valve 67 rotatably screwed and housed in the joint bolt 23 are provided. It is composed.

The extension side needle valve 67 has a distal end (lower end).
Can be advanced and retracted into the valve seat 66, and the upper end portion is the extension side operation portion 28. By rotating the extension-side operation section 28 of the extension-side needle valve 67 from outside with a tool such as a screwdriver, the extension-side needle valve 67 and the valve seat 6 are rotated.
6 can be changed. By the extension side needle valve 67, the piston rod 34 is passed through a bolt flow passage 69 formed in the joint bolt 23.
The hollow portion 34A and the reservoir chamber 31 can communicate with each other. Reference numeral 70 denotes a click mechanism for positioning the rotation position of the extension side needle valve 67.

In the compression stroke of one of the front forks 2, the poppet valve 37 of the piston valve mechanism 26 closes to block the holder flow path 51 during the compression stroke of the front fork 2. Although the hydraulic oil does not flow into the hollow portion 34A of the rod 34 and does not function, it functions during the extension stroke of the front fork 2. That is, during the extension stroke of one of the front forks 2, the damper cylinder 2
When the relative speed of the piston 33 with respect to 5 is medium to high, the poppet valve 37 opens, and the hydraulic oil in the upper piston chamber 45A flows into the hollow portion 34A of the piston rod 34 via the holder flow path 51, and extends. It is guided into the reservoir chamber 31 through the annular flow passage 68 between the side needle valve 67 and the valve seat 66. When the hydraulic oil flows through the annular flow path 68, a damping force is generated at the time of high speed on the extension side.

In the front fork 2, in the piston valve mechanism 26, a disc valve 46 that generates a damping force at the time of the extension side middle and high speed, a square hole 36 that generates a damping force at the time of extension side low speed, and the base In the valve mechanism 27, the disk valve 61 that generates the damping force when the compression side is at a high speed and the square hole 55 that generates the damping force when the compression side is at a low speed cannot be adjusted by an external operation. On the other hand, the damping force at the middle speed of the extension side generated in the annular flow path 68 between the extension side needle valve 67 and the valve seat 66 is caused by rotating the extension side operation section 28 of the extension side needle valve 67 from outside. The configuration can be adjusted by changing the channel area of the annular channel 68.

Here, as shown in FIG. 2, a sheet guide 19 is fitted into the upper end opening of the damper cylinder 25, and a rod guide 71 is accommodated in the sheet guide 19. Reference numeral 72 denotes an O-ring, which closes the upper end of the damper cylinder 25 in a liquid-tight manner. A third guide bush 73 is fixed to the inner periphery of the rod guide 71, and the third guide bush 73 can slide on the outer peripheral surface of the piston rod 34.

A rebound spring 74 is provided around the upper end of the damper cylinder 25. The rebound spring 74 abuts on the valve stopper 39 of the piston valve mechanism 26 when the one front fork 2 is fully extended, and regulates the maximum extension stroke of the one front fork 2. Further, an oil lock piece 75 is sandwiched between the bottom of the outer tube 11 and the damper cylinder 25,
An oil lock collar 76 is provided at the lower end of the inner tube 12.
Is attached. When the one front fork 2 is fully compressed, the oil lock function is exerted by the oil lock piece 75 and the oil lock collar 76, and the maximum compression stroke of the one front fork 2 is restricted.

An oil seal 77 is provided at the upper end opening of the outer tube 11 adjacent to the first guide bush 16. The oil seal 77 is attached to the outer tube 11 by a washer 78 and a stopper ring 79. A dust seal 80 is further provided adjacent to the oil seal 77. The oil seal 77 is provided in the reservoir chamber 3 through an opening 81 formed in the inner tube 12.
Hydraulic oil in 1 is guided and maintained in a wet state.

(3) The other front fork (FIGS. 7 to 1)
0) The other front fork 3 shown in FIG. 7 shows the most compressed state similarly to the one front fork 2 described above. In the other front fork 3, the same parts as those in the above-described one front fork 2 are denoted by the same reference numerals, and description thereof will be omitted.

In the other front fork 3, as shown in FIG. 7, an outer tube 11 and an inner tube 12 are slidably disposed, and a suspension spring 13 and a damper device are provided in both tubes 11 and 12. The damper device 86 is different from the damper device 14 of the one front fork 2. That is, the damper device 86 includes the damper cylinder 25, the piston valve mechanism 26, and the base valve mechanism 27, and further includes the compression-side damping force generation adjusting device 87 instead of the extension-side damping force generation adjusting device 29. You.

The compression-side damping force generation adjusting device 87 is disposed at the upper end of the inner tube 12.
As shown in FIG. 8, the poppet valve 37 and the valve seat 52 described above are removed from the piston holder 38 of the piston valve mechanism 26, and the lower piston chamber 45B is moved through the hollow portion 38A of the piston holder 38 to move the piston rod 34.
Is always communicated with the hollow portion 34A. Further, the piston upper chamber 45A and the piston lower chamber 45B are
Through the hollow portion 38A and the holder flow path 51.

The compression-side damping-force generation adjusting device 87 is configured as shown in FIG.
As shown in FIG. 10, a valve seat 88 screwed and fixed to the inner periphery of the upper end of the piston rod 34, and a pressure side needle valve 89 rotatably screwed and housed in the joint bolt 23. It is configured to have.

The pressure-side needle valve 89 has a distal end (lower end) which can be advanced and retracted into the valve seat 88, and an upper end which serves as a pressure-side operation section 90 as a pressure-side operation mechanism. By rotating the compression side operation unit 90 from the outside with a tool such as a screwdriver, the compression side needle valve 89 and the valve seat 8 are rotated.
8, the flow path area of the annular flow path 91 can be changed. The compression side needle valve 89 allows the hollow portion 34 of the piston rod 34 to pass through the bolt passage 69 of the joint bolt 23.
A and the reservoir chamber 31 can communicate with each other.

In the compression stroke of the other front fork 3, when the relative speed with respect to the damper cylinder 25 is medium or high, the hydraulic oil in the lower piston chamber 45B causes the hydraulic oil in the lower piston chamber 45B of the piston rod 34 to become hollow. Part 34
A, and flows into the pressure side needle valve 89 and the valve seat 88.
Through the annular flow passage 91 into the reservoir chamber 31. When the hydraulic oil flows through the annular flow path 91, a damping force is generated at the time of the pressure side middle and high speed.

As described above, since the upper piston chamber 45A and the lower piston chamber 45B are always in communication with each other through the holder flow path 51, the piston for the damper cylinder 25 can be moved in the compression stroke of the other front fork 3. When the relative speed of the piston 33 is low, the hydraulic oil in the lower piston chamber 45B is guided into the upper piston chamber 45A through the square hole 36 of the piston 33, and the piston holder 38
Is guided into the upper piston chamber 45A through the hollow portion 38A and the holder flow path 51, and the negative pressure in the upper piston chamber 45A is eliminated.

Further, in the extension stroke of the other front fork 3, the upper piston chamber 45A and the lower piston chamber 45B are always in communication with each other via the holder flow path 51 as described above. 3 during the extension stroke of the piston 3 with respect to the damper cylinder 25.
When the relative speed of the piston 3 is low, the hydraulic oil in the upper piston chamber 45A generates a damping force at the time of the extension side low speed while flowing into the lower piston chamber 45B through the square hole 36 of the piston 33, and the holder. The fluid flows into the lower piston chamber 45B through the flow path 51 and the hollow portion 38A of the piston holder 38, and generates a damping force at the time of the extension side low speed while flowing through the holder flow path 51.

Incidentally, in the piston valve mechanism 26,
In the compression stroke of the other front fork 3, when the relative speed of the piston 33 with respect to the damper cylinder 25 is medium or high, the hydraulic fluid in the lower piston chamber 45 </ b> B passing through the piston flow path 44 of the piston 33 causes the sax valve 35 to move.
The disc valve 46 and the valve presser 47 are pressed against the spring force of the valve spring 48, and this hydraulic oil flows through the opening 50 of the valve guide 40 into the piston upper chamber 45A, and the negative pressure of the piston upper chamber 45A is reduced. Relieve pressure. Further, during the extension stroke of the other front fork 3, the piston valve mechanism 26
When the relative speed of the piston 33 with respect to the valve 5 is medium to high, the inner peripheral portion of the disk valve 46 is bent and deformed by the hydraulic oil flowing through the opening 50 of the valve guide 40 and the valve flow path 49 of the valve presser 47, and the extension side medium high speed This hydraulic oil flows into the lower piston chamber 45B through the piston flow path 44 of the piston 33 while generating a damping force.

In the base valve mechanism 27,
In the compression and extension strokes of the other front fork 3, the same functions (damping force generation and negative pressure cancellation) as those in the compression and extension strokes of the one front fork 2 are performed.

In the other front fork 3, the piston valve mechanism 26 has a disk valve 46 for generating a damping force at the middle speed of the extension side, a square hole 36 for generating a damping force at the low speed of the extension side, and a base valve mechanism. 27
In FIG. 6, the disk valve 61 that generates the damping force at the time of the compression side middle and high speed and the square hole 55 that generates the damping force at the time of the compression side low speed cannot adjust the damping force by an external operation. On the other hand, the damping force generated in the annular flow path 91 between the compression side needle valve 89 and the valve seat 88 at the time of the compression side middle and high speeds is obtained by rotating the compression side operation portion 90 of the compression side needle valve 89 from the outside, and It is configured to be adjustable by changing the flow path area 91.

(4) Operation Next, the operation of the front fork assembly 1 including the one front fork 2 and the other front fork 3 will be described. (4-1) Compression Step of One Front Fork 2 In the compression step of one front fork 2, the poppet valve 37 closes to shut off the holder flow path 51.
Therefore, when the relative speed of the piston 33 to the damper cylinder 25 is low, the hydraulic oil in the lower piston chamber 45B flows into the upper piston chamber 45A through the square hole 36 of the piston valve mechanism 26, and the upper piston chamber 45A Is eliminated. At the same time, hydraulic oil equivalent to the volume of the piston rod 34 entering the damper cylinder 25 is supplied from the piston lower chamber 45B to the square hole 55 of the base valve mechanism 27.
Then, it flows into the reservoir chamber 31 through the base valve chamber 45C and the communication hole 32 while generating a damping force at the time of the compression side low speed.

In the compression stroke of the front fork 2, when the relative speed of the piston 33 with respect to the damper cylinder 25 is medium or high, the poppet valve 37 is also in the closed state, and the disc valve in the sax valve 35 of the piston valve mechanism 26. 46 and valve retainer 4
7 is pressed by the hydraulic oil in the lower piston chamber 45B against the spring force of the valve spring 48, and this hydraulic oil is released through the opening 50 of the valve guide 40 to the upper piston chamber 4B.
5A, the negative pressure in the upper piston chamber 45A is eliminated. Further, at the middle and high speeds, the hydraulic oil equivalent to the volume of the piston rod 34 entering the damper cylinder 25 flows from the lower piston chamber 45B into the opening 65 of the valve guide 57 in the base valve mechanism 27 and the valve flow of the Sachs valve 54. The inner peripheral portion of the disc valve 61 is bent and deformed through the passage 64, and flows into the reservoir chamber 31 through the base valve chamber 45 </ b> C and the communication hole 32. When the disk valve 61 is flexed and deformed, a damping force is generated at the time of the compression side medium speed.

(4-2) Compression stroke of the other front fork 3 In the compression stroke of the other front fork 3, when the relative speed of the piston 33 with respect to the damper cylinder 25 is low, the operation in the lower piston chamber 45B is performed. Oil flows through the square hole 36 of the piston valve mechanism 26 and the piston upper chamber 4
5A, and through the hollow portion 38A of the piston holder 38 and the holder flow path 51, the upper piston chamber 45A
And the pressure in the upper piston chamber 45A is released. At this low speed, hydraulic oil equivalent to the volume of the piston rod 34 entering the damper cylinder 25 flows from the piston lower chamber 45B into the square hole 5 of the base valve mechanism 27.
5 to generate a damping force at the time of low pressure side, and flow into the reservoir chamber 31 via the base valve chamber 45C.

In the compression stroke of the other front fork 3, when the relative speed of the piston 33 with respect to the damper cylinder 25 is medium or high, the disc valve 46 and the valve presser 47 of the piston valve mechanism 26 move the hydraulic oil in the lower piston chamber 45B. As a result, the hydraulic oil is pressed against the spring force of the valve spring 48, and a part of the hydraulic oil is guided into the upper piston chamber 45A through the opening 50 of the valve guide 40, and the negative pressure in the upper piston chamber 45A is released. Also,
At the middle and high speeds, the remaining hydraulic oil in the lower piston chamber 45B passes through the hollow portion 38A of the piston holder 38 and the hollow portion 34A of the piston rod 34, and the pressure side needle valve 89 and the valve in the pressure side damping force generation adjusting device 87. It flows into the reservoir chamber 31 through the annular flow path 90 with the seat 88 while generating a damping force at the medium side and high speed on the pressure side. Further, at the time of the middle and high speeds, the hydraulic oil equivalent to the volume of the piston rod 34 entering the damper cylinder 25 is discharged to the lower piston chamber 45B.
Through the opening 65 of the valve guide 57 in the base valve mechanism 27 and the valve passage 64 of the valve retainer 62 to bend and deform the inner peripheral portion of the disc valve 61 to generate a damping force at the medium side and high speed on the pressure side, It flows to the reservoir chamber 31 via the chamber 45C.

(4-3) Extension process of one front fork 2 In extension process of one front fork 2, the poppet valve 37 is opened and the upper piston chamber 45 A is connected to the piston rod 34 through the holder flow path 51. It is in communication with the hollow portion 34A. Accordingly, when the relative speed of the piston 33 with respect to the damper cylinder 25 is low, the hydraulic oil in the upper piston chamber 45A passes through the square hole 36 of the piston valve mechanism 26 to generate a damping force at the time of the low speed on the extension side. It flows into the lower chamber 45B. At this low speed, the hydraulic oil in the reservoir chamber 31 corresponding to the volume of the piston rod 34 retreating from the damper cylinder 25 is discharged to the base valve chamber 45.
C flows into the lower piston chamber 45B through the square hole 55 of the base valve mechanism 27 via C, and the negative pressure in the lower piston chamber 45B is released.

In the extension stroke of the front fork 2, when the relative speed of the piston 33 with respect to the damper cylinder 25 is medium to high, a part of the hydraulic oil in the upper piston chamber 45 A is removed by the valve guide 4 of the piston valve mechanism 26.
The inner peripheral portion of the disk valve 46 is bent and deformed through the opening 50 of the “0”, and flows into the lower piston chamber 45B while generating a damping force at the time of high speed at the extension side. At the time of the middle and high speeds, the upper piston chamber 45A and the piston rod 3
4 is in communication with the hollow portion 34A, the remaining hydraulic oil in the upper piston chamber 45A reaches the hollow portion 34A of the piston rod 34 via the holder flow path 51, and the extension side damping force generation adjusting device 29 It flows into the reservoir chamber 31 through the annular flow path 68 between the extension side needle valve 67 and the valve seat 66 while generating a damping force at the time of extension side middle and high speed. Further, at the middle and high speeds, the hydraulic oil in the reservoir chamber 31 corresponding to the volume of the piston rod 34 retreating from the damper cylinder 25 passes through the base valve chamber 45C and the base valve mechanism 2.
7 presses against the disc valve 61 and the valve retainer 62 against the spring force of the valve spring 64, flows from the opening 65 of the valve guide 57 into the lower piston chamber 45B, and eliminates the negative pressure in the lower piston chamber 45B. .

(4-4) Extension process of the other front fork 3 In the extension process of the other front fork 3 shown in FIG. 7, the piston upper chamber 45A, the piston lower chamber 45B, and the hollow portion 34A of the piston rod 34 are mutually connected. In communication. Therefore, when the relative speed of the piston rod 33 to the damper cylinder 25 is low, the piston upper chamber 45
A part of the hydraulic oil in A flows through the square hole 36 of the piston valve mechanism 26 into the lower piston chamber 45B while generating a damping force at the time of the extension side low speed, and the remaining hydraulic oil in the upper piston chamber 45A is removed. Then, it flows into the lower piston chamber 45B through the holder flow path 51 while generating a damping force at the time of low speed on the extension side. Also,
At this low speed, hydraulic oil equivalent to the retreat volume of the piston rod 34 from the damper cylinder 25 flows from the reservoir chamber 31 through the base valve chamber 45C, through the square hole 55 of the base valve mechanism 27, and into the lower piston chamber 45B. This eliminates the negative pressure in the lower piston chamber 45B.

In the extension stroke of the other front fork 3, when the relative speed of the piston 33 with respect to the damper cylinder 25 is medium to high, the hydraulic oil in the upper piston chamber 45 A discharges the disc valve 4 in the piston valve mechanism 26.
6 flows into the lower piston chamber 45B while flexing and deforming the inner peripheral portion of the piston 6 so as to generate a damping force at the time of high speed at the extension side. At this medium to high speed, hydraulic oil corresponding to the retreat volume of the piston rod 34 from the damper cylinder 25 passes from the reservoir chamber 31 to the base valve chamber 45C, and the disk valve 61 and the valve retainer 62 of the base valve mechanism 27 It is pressed against the spring force of 63 and flows into the lower piston chamber 45B to eliminate the negative pressure in the lower piston chamber 45B.

(5) Effects of the First Embodiment As described above, the front fork assembly 1 of the first embodiment has the following effects. On one front fork 2, a stretching side damping force generation adjusting device 29 that generates a damping force at the middle speed of the stretching side that can be adjusted by the stretching side operation unit 28 is installed, and a compression side that generates an adjustable compression side damping force. No damping force generation adjusting device is installed, and the other front fork 3 is provided with a compression side damping force generation adjusting device 87 that generates a damping force at the compression side medium / high speed that can be adjusted by the compression side operating section 90, Since the extension-side damping force generation adjusting device that generates the adjustable extension-side damping force is not installed, the compression damping force generation adjusting device and the stretching-side damping force generation adjustment device are used as the whole of the left and right front forks 2 and 3. Can be reduced one by one. For this reason, the cost of the front left and right front forks 2 and 3 as a whole, that is, the front fork assembly 1 of the motorcycle can be reduced.

The extension side damping force of the front forks 2 and 3 in the extension stroke of the front fork assembly 1 is adjusted by the extension side damping force generation adjusting device 29 of one of the front forks 2. Since the compression damping force of the front forks 2 and 3 in the compression stroke is adjusted by the compression damping force generation adjusting device 87 of the other front fork 3, during the extension stroke of the front forks 2 and 3 in the front fork assembly 1, The extension side damping forces generated in the left and right front forks 2 and 3 are different from each other, and the front forks 2 and 3 in the front fork assembly 1 are different.
3 in the compression stroke, the left and right front forks 2, 3
Are different from each other in the pressure side damping force. However, the difference between these damping forces is within the adjustable range of the damping force and is extremely small. Therefore, even if, for example, a difference is generated between the left and right front forks 2 and 3 (or between the compression side damping forces), the left and right front forks 2 and 3
Thus, the steering stability of the motorcycle can be ensured without adversely affecting the balance of No. 3.

Further, the extension side operation section 28 for operating the extension side damping force generation adjusting device 29 installed on one front fork 2 also operates the compression side damping force generation adjustment device 87 installed on the other front fork 3. The pressure side operation unit 90 to perform
Both are arranged at the upper end of the inner tube 12 of each of the front forks 2 and 3, so that a rider who rides on a motorcycle or the like can easily operate the operation sections 28 and 90 during traveling, and secure good operability. it can.

[B] Second Embodiment FIG. 11 is a half sectional side view showing one front fork of a front fork assembly showing a second embodiment of a suspension system for a motorcycle or the like according to the present invention. is there.
FIG. 12 is a half-side sectional view showing the lower part of FIG.

The front fork assembly 100 according to the second embodiment includes one of the front forks 2 of the front fork assembly 1 shown in FIG.
To one of the upright type front forks 11 shown in FIG.
It has been replaced with 0.

As shown in FIG. 11, the front fork 110 has an inner tube 112 inserted into an outer tube 111 and a suspension spring 113 and a damper device 114 built in between the two tubes 111 and 112. The inner tube 112 is supported on the vehicle body side, and the axle bracket 11 of the outer tube 111 is
At 5, the front wheels are supported. Front fork 1 shown
Numeral 10 indicates a 1G stroke state in which a rider is riding alone on a motorcycle.

A first guide bush 116 is provided on the inner periphery of the open end of the outer tube 111, and a second guide bush 117 is provided on the outer periphery of the lower end of the inner tube 112. The first guide bush 116 is the inner tube 11
The outer tube 111 and the inner tube 112 are slidable by sliding contact with the outer peripheral surface of the second tube 2 and sliding contact of the second guide bush 117 with the inner peripheral surface of the outer tube 111.

The lower end of the suspension spring 113 is connected to a lower spring seat 118 and a later-described damper cylinder 13.
1, and supported by the outer tube 111 via the axle bracket 115. The upper end of the suspension spring 113 has an upper spring seat 121 and a lock nut 1.
22, joint bolt 123 and fork cap 1
24 supported by the inner tube 112. The suspension spring 113 absorbs an impact force from a road surface.

The fork cap 124 is screwed and fixed to the upper end of the inner tube 112 to close the upper end of the inner tube 112. This fork cap 124
A hollow joint bolt 123 is screwed and fixed to
An upper end of a piston rod 140 described later is screwed and fixed to the joint bolt 123. Lock nut 122
Is screwed into the upper end of the piston rod 140 and abuts on the joint bolt 123 to perform the function of preventing the piston rod 140 from loosening the joint bolt 123. The upper spring seat 121 includes a lock nut 122.
And positioned.

As shown in FIG. 12, the damper device 114 includes a damper cylinder 131 erected from the outer tube 111, a piston valve mechanism 134 having a piston 132 for generating an extension-side damping force, and a compression-side damping force. And a base valve mechanism 137 provided with a bottom piston 135 and a square hole 136 that generate the pressure, and an extension-side damping force that enables the damping force generated during the extension-side middle and high-speed operation to be adjusted by an external operation of the extension-side operation mechanism 125. And a generation adjusting device 133. These piston valve mechanism 134, base valve mechanism 137 and extension side damping force generation adjusting device 13
3, the suspension spring 11
Outer tube 1 generated by the absorption of impact force by the outer tube 1
The expansion and contraction sliding of the inner tube 11 and the inner tube 112 is suppressed.

The damper cylinder 131 is disposed in the outer tube 111, and is screwed to a piston holder 149 described later to be erected. A reservoir chamber 138 is formed surrounded by the damper cylinder 131, the outer tube 111, and the inner tube 112. A communication hole 139 is formed in the damper cylinder 131, and the communication hole 139 allows the inside of the damper cylinder 131 (the base valve chamber 14).
5C) and the reservoir chamber 138 are communicated.

The piston 132 in the piston valve mechanism 134 is fixed to a piston rod 140 via a hollow piston holder 141. This piston 13
2, the interior of the damper cylinder 131 becomes the upper piston chamber 14
5A and a lower piston chamber 145B. The piston 132 is provided with an extension side flow path (not shown) and a compression side flow path 14.
2 are formed so as to penetrate in the axial direction, and the extension side valve 143 and the compression side valve (check valve) 14
4 are provided.

The pressure side valve 144 is connected to the front fork 1
In the compression stroke of No. 10, when the relative speed of the piston 132 to the damper cylinder 131 is medium to high, the valve is opened by the hydraulic oil (oil level h) guided from the lower piston chamber 145B to the pressure side flow path 142, and this hydraulic oil is opened. To the upper piston chamber 145A to eliminate the negative pressure in the upper piston chamber 145A.

Further, during the extension stroke of the front fork, when the relative speed of the piston 132 with respect to the damper cylinder 131 is medium to high during the extension stroke of the front fork, the hydraulic oil guided from the piston upper chamber 145A to the extension side flow path is used. It is flexed and deformed, and the hydraulic oil flows to the lower piston chamber 145B, and generates a high-speed damping force during extension.

The bottom piston 135 of the base valve mechanism 137 is fixed to the piston holder 149 and the holder piece 148. This bottom piston 135
, A compression-side flow path (not shown) and an expansion-side flow path 150 are formed penetrating in the axial direction, and a compression-side valve 151 and an expansion-side valve (check valve) 152 are attached to both axial end surfaces. . This bottom piston 135 forms a base valve chamber 145C that is partitioned into a piston lower chamber 145B. Piston holder 149 and holder piece 1
Reference numeral 48 denotes a hollow shape, which is screwed together, and the piston holder 149 is fixed to the axle bracket 115 via a hollow center bolt 153.

In the compression stroke of the front fork 110, when the relative speed of the piston 132 with respect to the damper cylinder 131 is medium or high, the pressure side valve 151 moves into the piston rod 140 which enters the damper cylinder 131.
Is deformed when it is guided from the lower piston chamber 145B to the pressure side flow path, this hydraulic oil is guided to the reservoir chamber 138 via the base valve chamber 145C and the communication hole 139, and Generates damping force at medium and high speeds.

In the extension stroke of the front fork 110, the hydraulic oil equivalent to the volume of the piston rod 140 withdrawing from the damper cylinder 131 moves from the reservoir chamber 138 to the communication hole 139 and the base valve chamber 145 C during the extension stroke of the front fork 110. The valve is opened when the flow reaches the expansion side flow path 150 through the piston, and this hydraulic oil is guided to the lower piston chamber 145B, and the negative pressure in the lower piston chamber 145B is eliminated.

The square hole 1 of the base valve mechanism 137
36 is formed in the piston holder 149 and connects the lower piston chamber 145B and the base valve chamber 145C to the communication hole 1.
Communication can be made via 39. In the compression stroke of this one front fork 110, the damper cylinder 131
When the relative speed of the piston 132 is low, the piston rod 140 that enters the damper cylinder 131
Hydraulic oil equivalent to the intrusion volume of the reservoir chamber 13 flows from inside the piston lower chamber 145B through the square hole 136 and the communication hole 139.
8, the hydraulic oil flows through the square hole 136, and a damping force at the low pressure side is generated. In the extension stroke of one of the front forks 110, when the relative speed of the piston 132 to the damper cylinder 131 is low, hydraulic oil corresponding to the retreat volume of the piston rod 140 from the damper cylinder 131 is communicated from the reservoir chamber 138. It flows into the lower piston chamber 145B through the hole 139 and the square hole 136,
The negative pressure in the lower piston chamber 145B is eliminated.

The expansion-side damping force generation adjusting device 133 includes an expansion-side needle valve 155 rotatably disposed in a piston holder 141.
Is operated by the extension side operation mechanism 125. The extension-side operation mechanism 125 includes an operation rod 1 housed in a piston rod 140 and rotatably fitted to the extension-side needle valve 155.
26, and a needle valve adjuster 127 rotatably screwed into the joint bolt 123 and rotatably fitted to the operation rod 126.

By rotating the needle valve adjuster 127 with a tool such as a screwdriver, the extension side needle valve 15 is rotated.
The flow path area of the annular flow path 128 between the piston 5 and the piston holder 141 can be changed. The extension side needle valve 155 allows the holder flow path 12 formed in the piston holder 141 to be opened.
9, the upper piston chamber 145A and the lower piston chamber 145
B is provided so as to be able to communicate.

When the relative speed of the piston 132 with respect to the damper cylinder 131 is medium or high during the extension stroke of the front fork 110, the extension side damping force generation adjusting device 133 transfers the hydraulic oil in the piston upper chamber 145A to the holder flow. Piston lower chamber 145 via passage 129 and annular passage 128
B, when the hydraulic oil flows through the annular flow path 128, a damping force is generated at the time of high speed on the extension side.

In the front fork 110,
The piston valve mechanism 134 generates an expansion side valve 143 that generates a damping force at medium- and high-speeds on the expansion side. The damping force of the square hole 136 cannot be adjusted by an external operation. On the other hand, the extension side damping force generation adjusting device 133
The damping force at the middle side of the extension side generated in the annular flow path 128 between the needle valve adjuster 127 and the piston holder 141 at the time of extension is provided so as to be adjustable by operating the needle valve adjuster 127 of the extension side operation mechanism 125 from outside. Can be

Here, as shown in FIG. 11, the rod guide case 15
The rod guide 159 is accommodated in the rod guide case 158. Reference numeral 160 denotes an O-ring. A third guide bush 161 is fixed to the inner periphery of the rod guide 159.
Are configured to be slidable on the outer peripheral surface of the piston rod 140.

Further, a rebound spring 130 is mounted on the outer periphery of the damper cylinder 131, and the rebound spring 130 allows one of the front forks 11.
The maximum extension stroke of 0 is regulated. Further, a hydraulic oil lock piece 156 is fixed to the bottom of the outer tube 111, and a hydraulic oil lock collar 157 is attached to the lower end of the inner tube 112. These hydraulic oil lock pieces 1
The hydraulic oil lock function is exerted by 56 and the hydraulic oil lock collar 157, and the most compression stroke of one front fork 110 is regulated.

A hydraulic oil seal 162 is attached to the lower end opening of the outer tube 111 so as to be adjacent to the first guide bush 116 in the axial direction.
Further, a dust seal 163 is provided adjacent to 62. Hydraulic oil in the reservoir chamber 138 is guided to the hydraulic oil seal 162 through an opening 154 opened in the inner tube 112, and is maintained in a wet state.

Next, the operation of one front fork 110 will be described. In the compression stroke of the one front fork 110, the square hole 13 of the base valve mechanism 137 is formed.
When the hydraulic oil flows through the hydraulic valve 6, a damping force at the low pressure side is generated, and the hydraulic oil is supplied to the hydraulic valve 15 of the base valve mechanism 137.
When 1 is flexurally deformed, a damping force is generated at the time of the compression side middle and high speed.

In the extension stroke of one of the front forks 110, when hydraulic oil flows through the extension side needle valve 155 of the extension side damping force generation adjusting device 133 and the annular flow path 128 of the piston holder 141, the extension side medium speed is high. When the hydraulic oil causes the expansion valve 143 of the piston valve mechanism 134 to bend and deform, a damping force at the time of the expansion medium speed is generated.

Only the damping force of the extension-side damping force generating / adjusting device 133 at the time of extension-side middle-high speed can be adjusted by operating the needle valve adjuster 127 of the extension-side operation mechanism 125 from outside.

In the front fork assembly 100 including the one front fork 110 configured as described above and the other front fork 3 described above, only the one front fork 110 is operated by the extension side operation mechanism 125. An adjusting device 133 for generating a damping force at the extension side which is adjustable to generate a damping force at the medium speed at the extension side is installed. Of the left and right front forks 1
As a whole, the extension side damping force generation adjusting device and the compression side damping force generation adjusting device can be reduced one by one, and the cost can be reduced.

Further, the damping force of the left and right front forks 110 and 3 is only different within the damping force adjustment range of the extension side damping force generation adjusting device 133 and the compression side damping force generation adjusting device 87. The balance of the front forks 110 and 3 is not lost, and the steering stability of the motorcycle can be secured well.

Further, the extension-side operating mechanism 1 for adjusting the extension-side damping force generation adjusting device 133 of the front fork 110
25 needle valve adjusters 127 are the inner tube 1
12, the rider can easily adjust the damping force from above, as in the case of the pressure-side operation portion 90 of the other front fork 3, and secure good operability.

In the first and second embodiments, the square hole 36 of the piston valve mechanism 26, the square hole 55 of the base valve mechanism 27, and the one front fork 2 of the front fork 2 and the front fork 3 of the other. Square hole 1 of base valve mechanism 137 in fork 110
36 may be omitted.

[0101]

As described above, according to the front wheel suspension system for a motorcycle or the like according to the present invention, it is possible to reduce the cost while ensuring good steering stability.

[Brief description of the drawings]

FIG. 1 is an overall front view of a front fork assembly showing a first embodiment of a front wheel suspension device for a motorcycle or the like according to the present invention.

FIG. 2 is a half sectional view showing one front fork of FIG. 1;

FIG. 3 is a side sectional view showing a periphery of a piston and a rod of FIG. 2;

FIG. 4 is a half sectional view showing an upper end portion of FIG. 2;

FIG. 5 is a view on arrow V in FIG. 4;

FIG. 6 is a side sectional view showing around a base piston of FIG. 2;

FIG. 7 is a half sectional view showing the other front fork of FIG. 1;

FIG. 8 is a side sectional view showing the vicinity of a piston and a rod of FIG. 7;

FIG. 9 is a half sectional view showing the upper end of FIG. 7;

FIG. 10 is a view as viewed in the direction of the arrow X in FIG. 9;

FIG. 11 is a half sectional view showing one of the front forks of a front fork assembly showing a second embodiment of the suspension system for a motorcycle or the like according to the present invention.

FIG. 12 is a half-side sectional view showing the lower part of FIG. 11;

[Explanation of symbols]

 Reference Signs List 1 front fork assembly 2 one front fork 4 under bracket (steering bracket) 11 outer tube (wheel side tube) 12 inner tube (vehicle side tube) 14 damper device 25 damper cylinder 26 piston valve mechanism (extension damping force generator) 27 Base valve mechanism (compression-side damping force generator) 28 Extension-side operation section (extension-side operation mechanism) 29 Extension-side damping force generation adjusting device 31 Reservoir chamber 33 Piston 34 Piston rod 35 Sachs valve 36 Square hole 37 Poppet valve 45A On piston Chamber 45B Piston lower chamber 45C Base valve chamber 46 Disc valve 51 Holder channel 53 Base piston 54 Sachs valve 55 Square hole 61 Disc valve 66 Valve seat 67 Extension needle valve 68 Ring Flow path 86 Damper device 87 Compression side damping force generation and adjustment device 88 Valve seat 89 Compression side needle valve 90 Compression side operating section 91 Annular flow path 100 Front fork assembly 110 One front fork 111 Outer tube (wheel side tube) 112 Inner tube (body side) Tube) 114 damper device 125 extension side operation mechanism 127 needle valve adjuster 128 annular flow path 131 damper cylinder 132 piston 133 extension side damping force generation adjusting device 134 piston valve mechanism (extension side damping force generation device) 135 bottom piston 136 square hole 137 Base valve mechanism (compression-side damping force generator) 138 Reservoir chamber 140 Piston rod 143 Extension-side valve 145A Upper piston chamber 145B Lower piston chamber 145C Base valve chamber 151 Compression valve B 155 Extension needle valve

Claims (4)

[Claims] The left and right front forks can be pivotally supported on a vehicle body via a steering bracket.
Each front fork rotatably supports a front wheel, and the front forks each include a vehicle body-side tube supported by the steering bracket, and a wheel-side tube that supports the front wheel and is slidably fitted to the vehicle body-side tube. And a damper device including a damping force generating device that generates damping force by being housed in both of these tubes. A front wheel suspension device such as a motorcycle configured to include: The device has an extension-side damping force generation adjustment device in which the extension-side damping force can be adjusted by an external operation of an extension-side operation mechanism disposed at the upper end of the body-side tube in the one front fork. The damper device on the other side of the front fork is provided outside the pressure side operation mechanism disposed at the upper end of the body side tube of the other front fork. Front wheel suspension device such as a motorcycle, characterized in that it has a compression side damping force generating adjusting device compression side damping force is adjustable by the operation of the. 2. The damper device of one of the front forks, comprising: a damper cylinder that stands on a wheel-side tube and fills the inside with a hydraulic oil; and a slidably disposed via a piston in the damper cylinder. A hollow rod having an upper end attached to the vehicle body side tube, an upper piston chamber and a lower piston chamber in the damper cylinder partitioned by the piston, and an oil reservoir formed outside the damper cylinder. A damping force generating device for generating a damping force by hydraulic oil flowing between the chambers; and a flow passage in the rod, which is provided in the rod and communicates the piston upper chamber and the oil reservoir, with the vehicle body The extension side operating mechanism arranged at the upper end of the side tube can be changed to adjust the extension side damping force generated in the extension side stroke of the front fork in the flow path. Front wheel suspension device such as a motorcycle according to claim 1 and the extension side damping force generating adjusting device, and has a. 3. The damper device of the other front fork, a damper cylinder standing upright on a wheel side tube and filling the inside with hydraulic oil, and slidably disposed in the damper cylinder via a piston. A hollow rod having an upper end attached to the vehicle body side tube, an upper piston chamber and a lower piston chamber in the damper cylinder partitioned by the piston, and an oil reservoir formed outside the damper cylinder. A damping force generating device for generating a damping force by hydraulic oil flowing between the chambers, and a flow passage in the rod, which is disposed in the rod and communicates the piston lower chamber and the oil reservoir, with the vehicle body The pressure can be changed by a pressure side operation mechanism disposed at the upper end of the side tube, and the pressure side damping force generated in the pressure side stroke of the front fork can be adjusted in the flow path. Front wheel suspension device such as a motorcycle according to claim 1 or 2, one having a compression side damping force generating adjusting device. 4. The damper device of one of the front forks is provided with a damper cylinder erected on a wheel-side tube and filled with hydraulic oil therein, and slidably disposed in the damper cylinder via a piston. A hollow rod having an upper end attached to the vehicle body side tube, an upper piston chamber and a lower piston chamber in the damper cylinder partitioned by the piston, and an oil reservoir formed outside the damper cylinder. A damping force generating device that generates a damping force by hydraulic oil flowing between the chambers; and a passage in the rod, which is provided in the rod and communicates the upper piston chamber and the lower piston chamber, with the vehicle body The extension side damping force generated during the extension side stroke of the front fork can be adjusted in the above-mentioned flow path by making it changeable by the extension side operation mechanism arranged at the upper end of the side tube. Front wheel suspension device such as a motorcycle according to claim 1 or 3 and the extension side damping force generating adjusting device, and has a to.