JP2001082529A - Suspension device for motorcycle or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension device to leave the center of gravity of a motorcycle body at the rear side by increasing the air reaction force of a front fork during brake when the motorcycle body on the front side of the motorcycle is sunk and further suppress movement of the center of gravity of the motorcycle body to the rear side by decreasing the air reaction force of a front fork during acceleration when the motorcycle body on the front side is floated, and improve running stability of the motorcycle. SOLUTION: An air cylinder device 15 consisting of a cylinder 16 and a rod 17 slid in the cylinder 16 is pivotally supported between a motorcycle body frame 1 and an oscillation arm 11 to rotatably support a rear wheel 12 such that an air chamber in the air cylinder device 15 is compressed during braking and the air chamber is expanded during acceleration. The air chamber in the air cylinder device 15 is connected to an air chamber in a front fork 4 through a conduit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device interposed between a vehicle body and a wheel of a motorcycle or the like to absorb a shock from a road surface, and more particularly to a suspension device for an on-road racing motorcycle or the like. The present invention relates to a suitable suspension device.

[0002]

2. Description of the Related Art When a motorcycle is braked, the center of gravity of the vehicle moves to the front side due to the inertia force of the vehicle body. If the braking force is large, the rear wheels may be separated from the road surface and running stability may be impaired. In addition, during acceleration, the center of gravity of the vehicle moves to the rear side, and the front wheels are lifted up, so that the running stability may be impaired as in the case described above.

Further, in a motorcycle, when braking or accelerating, the center of gravity of the vehicle moves toward the front side or the rear side, respectively, and a behavior called pitching occurs, and this behavior may cause the tire of the front wheel or the rear wheel to lose the ground contact force. There is.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to increase the air reaction force of the front fork during braking when the front side of the vehicle body sinks, leaving the vehicle center of gravity on the rear side.
It is an object of the present invention to provide a suspension device that improves the running stability of a motorcycle by reducing the air reaction force in a front fork and suppressing the vehicle center of gravity from moving to the rear side during acceleration when the front side floats.

[0005]

According to a first aspect of the present invention, there is provided a front fork having a body side tube and a wheel side tube slidably fitted therein and having an air chamber formed therein. Provided between the side and the axle of the front wheel, the base end of a swing arm that pivotally supports the rear wheel at the tip at the rear end of the body frame is swingably supported, and the rear side of the body frame In a suspension device such as a motorcycle provided with a hydraulic shock absorber between a swing arm and a swing arm, a rod provided with a piston portion at a tip is slidably inserted into a cylinder, and the rod is provided inside the cylinder with the piston portion. An air cylinder device having an air chamber defined between the air cylinder devices, wherein the rod enters the cylinder of the air cylinder device when the swing arm pivots downward, and the air chamber in the air cylinder device is compression When the swing arm is pivoted upward, the rod of the air cylinder device is moved to the body frame so that the rod is retracted from the cylinder of the air cylinder device and the air chamber in the air cylinder device is enlarged. And one of the rocking arms, and the rod is pivotally supported on the other of the body frame and the rocking arm,
The air chamber in the air cylinder device is connected to the air chamber in the front fork via a conduit.

According to a second aspect of the present invention, in the first aspect of the present invention, an oil chamber is further provided in a lower portion of the front fork, and an air chamber is provided in an upper portion of the oil chamber. And a first free piston is provided to divide the air chamber into upper and lower air chambers.

According to a third aspect of the present invention, in the second aspect of the present invention, further, an orifice plate having an orifice hole formed therein is fixed to an inner periphery of a vehicle body side tube above the first free piston, A damper oil chamber communicating with the upper portion of the first free piston through the orifice hole is formed.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a second free piston is provided on an upper surface of a damper oil chamber formed above the first free piston. It is.

[0009]

According to the first aspect of the present invention, the following operations are provided. At the time of braking, the vehicle center of gravity of the motorcycle moves to the front side due to inertia force, and the vehicle body side tube of the front fork enters the wheel side tube. Then, the air chamber in the front fork is compressed, and the pressure in the air chamber increases. At the same time, the rear side of the body frame rises, and the swing arm pivotably supported on the rear side of the body frame pivots downward.

As a result, the rod of the air cylinder device pivotally supported by the swing arm enters the cylinder of the air cylinder device pivotally supported by the vehicle body side frame, and the air chamber in the air cylinder device is compressed. . Then, the pressure of the air chamber in the front fork communicating with the air chamber via the conduit increases, and the load moved to the front side is pushed back to prevent the rear wheel tire from separating from the road surface.

At the time of acceleration, contrary to braking, the center of gravity of the vehicle moves to the rear side, the body-side tube of the front fork retreats from the inside of the wheel-side tube, and the air chamber inside the front fork expands. The pressure in the chamber drops.
At the same time, the rear body frame sinks, and the swing arm swingably supported by the body frame rotates upward. As a result, the rod of the air cylinder device rotatably supported by the swing arm retreats from the cylinder, the air chamber in the air cylinder device expands, and the air chamber in the front fork communicates via a conduit. Pressure drops. Therefore,
It prevents the center of gravity of the vehicle from moving to the rear side and prevents the front wheels from lifting.

Further, even during turning, the rear side of the vehicle body sinks due to centrifugal force. In this case, as in the case of acceleration, since the swing arm pivots upward and the rod withdraws from the air cylinder device, the air reaction force in the front fork decreases,
The contact force of the front tire and the ability to absorb vibration from the road surface can be increased.

According to the second aspect of the present invention, the following operations are provided. The first free piston is provided in the air chamber formed in the upper part of the front fork, and the air chamber is divided into upper and lower air chambers. Therefore, the hydraulic oil in the oil chamber formed in the lower part of the front fork becomes the first oil. Is not blocked by the free piston and does not enter the air cylinder device. Therefore, the operation of the air cylinder device is not hindered.

According to the third aspect of the present invention, the following operations are provided. When the swing arm has a small stroke at a high frequency, a similar pressure fluctuation occurs in the air cylinder device. This pressure fluctuation is transmitted to the upper air chamber in the front fork via the conduit, but is blocked by the damper oil chamber provided above the first free piston, and is not transmitted to the air chamber below the first free piston. . That is, the hydraulic oil in the upper part of the orifice plate cannot flow into the lower part of the orifice hole due to the resistance of the orifice hole. Therefore, even if the swing arm has a small stroke at a high frequency, the front fork does not vibrate minutely.

According to the fourth aspect of the invention, the following operation is provided. Since the second free piston is provided on the upper surface of the damper oil chamber formed above the first free piston, the hydraulic oil in the damper oil chamber does not enter the air chamber in the air cylinder device. Therefore, there is no hindrance to the operation of the air cylinder device.

[0016]

FIG. 1 is a schematic view showing a motorcycle to which a suspension device according to the present invention is applied. FIG. 2 is a cross-sectional view of an air cylinder device and an upper half cutaway view of a front fork of a first embodiment. 3 is a lower half sectional view of the front fork of the first embodiment, FIG. 4 is an upper half sectional view of the front fork of the second embodiment, FIG. 5 is an upper half sectional view of the front fork of the third embodiment, and FIG. FIG. 7 is a schematic diagram showing a motorcycle in which an air cylinder device of a suspension device is directly disposed between a body frame and a swing arm according to a third embodiment of the present invention.

(First Embodiment) (FIGS. 1 to 3 and 7) FIG. 1 shows a motorcycle to which a suspension device 10 according to the present invention is applied.
And a front fork 4 between the axle 3 that supports the front wheel 2. The front fork 4 is slidably fitted in an inner tube 5 forming a vehicle body side tube in an outer tube 6 forming a wheel side tube.
Is connected to the head pipe 7 at the front end of the front side 1A of the vehicle body frame 1 via upper and lower brackets 8 and 9 so as to be swingable in the left-right direction. The outer tube 6 is connected to the axle 3 of the front wheel 2.
Is combined with

A pivot shaft 8 fixed to the rear side 1B of the vehicle body frame 1 pivotally supports a base end portion of a swing arm 11 so as to be swingable. Is rotatably supported. A seat frame 1C extending rearward from an upper portion of the rear side 1B of the body frame 1 and forming a part of the rear side 1B of the body frame 1;
A hydraulic shock absorber 13 is provided between the swing arm 11 and a shaft a fixed to an intermediate portion of the swing arm 11. Since the hydraulic shock absorber 13 is a known one, a detailed description thereof will be omitted.

A down tube 14 which supports an engine (not shown) and forms a part of the body frame 1 is provided extending forward from a lower portion of the rear side 1B of the body frame 1 and provided below the down tube 14. An air cylinder device 15 is disposed substantially parallel to the down tube 14. The cylinder 16 of the air cylinder device 15 is pivotally supported by a shaft f fixed to the distal end of the down tube 14,
The base end of the rod 17 that slides inside is pivotally supported by the swing arm 11 via a link mechanism 20 described later.

Here, as shown in FIG. 2, the air cylinder device 15 comprises a cylinder 16 and a rod 17 which is slidably inserted into the cylinder 16 and has a piston portion 17A at the tip. A seal member 21 that is prevented from coming off by a stopper ring 21A is fitted on the inner periphery of the opening side of the cylinder 16, and a bush 22 is fitted on the outer periphery of the piston portion 17A at the tip of the rod 17. An air chamber A is formed between the inner circumference of the cylinder 16 and the piston 17A at the tip of the rod 17.

The link mechanism 20 is composed of an integral block 28 composed of a tension rod 27 and four sides 23, 24, 25, 26. The base end of the tension rod 27 is located at the middle of the swing arm 11. One end is pivotally supported on a shaft e fixed behind the fixed shaft a. Block 28
Each of the four vertices is inserted through a shaft a fixed to the intermediate portion of the swing arm 11, a shaft b fixed to the rear end of the damper tube 14, and a base end of the rod 17 of the air cylinder device 15. The shaft c and the shaft d inserted through the tip of the tension rod are pivotally connected to each other. In FIG. 2, reference numeral 16A denotes an axis f of the distal end of the down tube 14.
A mounting portion 17B of the cylinder 16 pivotally supported by the rod 17 is a mounting portion of the rod 17 pivotally supported by the shaft c of the block 28.

When the swing arm 11 is rotated downward in the direction P in FIG. 1, the block 28 is rotated clockwise about the shaft b to push the rod 17, and the rod 17 is moved by the air cylinder device 15 And the air chamber A in the air cylinder device 15 is compressed.

When the swing arm 11 is rotated upward in the direction Q in FIG. 1, the block 28 is rotated counterclockwise about the axis b to pull the rod 17, and
7 retreats from the inside of the cylinder 16 of the air cylinder device 15 to enlarge the air chamber A in the air cylinder device 15.

However, the link mechanism 20 is not always necessary, and as shown in the suspension device 100 of FIG.
A lever portion 11A is provided integrally with the swing arm 11 below the intermediate portion of the swing arm 11, and the air cylinder device 15 is provided between the lever portion 11A and a mounting portion 14A provided below the down tube 14. You may pivot.

In FIGS. 1 and 7, the cylinder 16 of the air cylinder device 15 is moved to the swing arm 11 side by the rod 1.
7 may be pivotally supported on the down tube 14 or the rear side 1B of the body frame 1, respectively. The point is the swing arm 11
The air cylinder A in the air cylinder device 15 is compressed between the body frame 1 and the swing arm 11 so that the air chamber A in the air cylinder device 15 is compressed at the time of downward rotation and the air chamber A is enlarged at the time of upward rotation.
5 may be provided.

As shown in FIG. 2, an air joint 19 is screwed to the cylinder 16 of the air cylinder device 15, one end of a conduit 18 is connected to the air joint 19, and the other end of the conduit 18 is connected to the other end of the conduit 18. Other air joint 28
The other air joint 28 is screwed to a cap 36 for closing the upper end of the inner tube 5 of the front fork 4 described later. The air chamber A in the air cylinder device 15 communicates with the air chamber B in the front fork 4 via the conduit 18. 29 is an air valve.

As shown in FIGS. 2 and 3, the front fork 4 has an inner tube 5 connected to the vehicle body side slidably fitted in an outer tube 6 connected to the axle side. A bush 30 is fitted around the distal end of the tube 5, and a bush 31 is fitted around the inner circumference of the opening of the outer tube 6.
And the oil seal 32 are fitted. An oil chamber C is formed below the front fork 4, and an air chamber B is formed above the oil chamber C. Further, a cap 36 is screwed to the upper end of the inner tube 5 via an O-ring 35,
The ring 35 hermetically seals the upper air chamber B in the front fork 4.

A lower portion of the seat pipe 37 is screwed to a bottom portion of the outer tube 6 by a bolt 41 while sandwiching a flange portion 40A below the oil lock piece 40, and formed at an upper end portion of the seat pipe 37. The piston portion 37A has a piston ring 42 on the inner circumference of the inner tube 5.
Sliding contact via A copper packing 41A is interposed between the head of the bolt 41 and the lower end surface of the outer tube 6, and seals the oil chamber C in the front fork 4 in a liquid-tight manner.

The seat pipe 37 divides the oil chamber C in the front fork 4 into an outer oil chamber C1 and an inner oil chamber C2, and has a plurality of large-diameter holes 43 formed in the lower part and small holes in the upper part. 44 are formed.

A spacer collar 45 is sandwiched between the upper inner periphery of the inner tube 5 and the outer periphery of the cap 36, and an annular upper spring receiver 46 is provided at the lower end of the spacer collar 45 in contact with the upper collar. A suspension spring 47 is disposed between the receiver 46 and the upper end of the seat pipe 37 in the extension direction.

A cylindrical oil lock collar 50 is provided on the inner periphery of the distal end portion of the inner tube 5, and a valve stopper 51 provided at an upper portion and a washer 52 provided at a lower portion.
And these are fixed between the inner tube 5 and the inner peripheral step by caulking the tip of the inner tube 5 inward.

Further, an annular free valve 53 is provided between the valve stopper 51 and the tapered valve seat surface 50A formed in the upper inner periphery of the oil lock collar 50 so as to be vertically movable. A valve spring 54 interposed between the stopper 51 and the valve spring 54 urges the valve seat surface 50A of the oil lock collar 50.

A check valve 55 is vertically movable between a lower inner peripheral step portion of the oil lock collar 50 and the washer 52, and a slight gap is formed between the check valve 55 and the inner periphery of the oil lock collar 50. Provided.

A rebound spring 5 is provided between the valve stopper 51 and the piston portion 37A of the seat pipe 37.
7 are provided.

With such a configuration, the front fork 4 has a buffer function as described below.

(Compression stroke) When the inner tube 5 enters the outer tube 6, the suspension spring 47 bends and the upper air chamber B in the front fork 4 is compressed, and the spring reaction force of the suspension spring 47 and the upper air chamber B A reaction force is generated by combining the air reaction force of

When the free valve 53 moves upward, the hydraulic oil in the lower oil chamber of the free valve 53 flows into the upper oil chamber, and the volume of the inner tube 5 that has entered the oil chamber C1 outside the seat pipe 37. A considerable amount of hydraulic oil is in the seat pipe 37
Through the lower large-diameter hole 43 into the inner oil chamber C2. As a result, a compression-side damping force is generated in the lower large-diameter hole 43.

At the time of maximum compression, the check valve 55 and the oil lock collar 50 provided on the inner periphery of the distal end portion of the inner tube 5 are fitted to the outer periphery of the oil lock piece 40 provided on the outer periphery of the lower portion of the seat pipe 37, and the check valve 55 The hydraulic oil is confined in the lower part of the cylinder to buffer the most compression.

The reaction force obtained by combining the spring reaction force of the suspension spring 47 and the air reaction force of the air chamber A and the compression damping force buffer the compression of the front fork 4.

(Extension Stroke) When the inner tube 5 retreats from the outer tube 6, the suspension spring 47 expands and the volume of the air chamber B increases. At the time of this extension, the free valve 53 is seated on the valve seat surface 50A of the oil lock collar 50, so that the hydraulic oil in the upper oil chamber of the free valve 53 passes through the small hole 44 on the upper part of the seat pipe 37 and passes through the small hole 44 It flows to the inner oil chamber C2. Thereby, the extension side damping force is generated in the small hole 44. In addition, hydraulic oil corresponding to the volume of the inner tube 5 withdrawn from the oil chamber C1 outside the seat pipe 37 passes through the large-diameter hole 43 from the oil chamber C2 inside the seat pipe 37 and the free valve 53.
And the negative pressure in the lower oil chamber of the free valve 53 is prevented.

In the transitional stage of the extension stroke in which the oil lock collar 50 comes out of the oil lock piece 40, the check valve 55 on the inner circumference of the inner tube 5 moves downward, and the check valve 55 moves from the inner circumference of the check valve 55.
Replenish hydraulic oil to the oil chamber below.

At the time of the maximum extension, the rebound spring 57 abuts against the lower end of the piston portion 37A at the upper end of the seat pipe 37 to buffer the maximum extension.

The suspension device 10 of the present invention operates as follows. When the motorcycle is braked and decelerated when entering a corner from a high-speed straight running state, the center of gravity of the vehicle body moves to the front side 1A of the vehicle body frame 1 by inertia force, and the inner tube 5 of the front fork 4 is in the outer tube 6 And the front side 1A of the body frame 1 sinks. On the other hand, the rear side 1B of the body frame 1
Is lifted, and the swing arm 11 rotates around the pivot shaft 8 in the direction P in FIG. 1, that is, rotates downward.

As a result, when the swing arm 11 is rotated downward, the block 28 is moved to the shaft b behind the down tube 14.
, The rod 17 pivotally supported on the block 28 by the axis c is pushed forward, and the rod 17 enters the cylinder 16. As a result, the air chamber A in the air cylinder device 15 is compressed, and the air reaction force in the upper air chamber B in the front fork 4 communicating with the air chamber A via the conduit 18 increases, so that the body frame 1 The load moved to the front side 1A is pushed back.

When the motorcycle accelerates, the center of gravity of the vehicle moves to the rear side 1B of the body frame 1, the front side 1A of the body frame 1 rises, and the rear side 1B of the body frame 1 sinks. Then, the swing arm 11 rotates around the pivot shaft 8 in the Q direction in FIG. 1, that is, rotates upward, and the block 28 rotates counterclockwise around the shaft b behind the down tube 14, The rod 17 pivotally supported on the block 28 by the axis c is pulled backward, and the rod 17 is withdrawn from the cylinder 16 of the air cylinder device 15,
The air chamber A in the air cylinder device 15 is enlarged. As a result, the air reaction force of the upper air chamber B in the front fork 4 communicating with the air chamber A via the conduit 18 is reduced, and the retraction of the inner tube 5 from the outer tube 6 is suppressed,
The movement of the vehicle center of gravity toward the rear side can be suppressed.

Further, even during turning, the rear side 1B of the vehicle body frame 1 sinks due to centrifugal force, so that the swing arm 11 rotates upward about the pivot shaft 8 as in the case of acceleration. The rod 17 of the cylinder device 15 is the cylinder 1
6, the air chamber A in the air cylinder device 15 expands, and the front fork 4 communicates via the conduit 18.
The air reaction force of the air chamber B in the inside decreases. As a result, the lifting of the front side 1A of the vehicle body frame 1 can be suppressed, and the contact force and absorbency of the tire of the front wheel 2 can be increased.

As described above, the sinking of the front side 1A of the vehicle body frame 1 is prevented during braking, and
Since the lifting of the front side 1A of the vehicle body frame 1 is suppressed, the pitching behavior of the vehicle body can be suppressed.

In the present embodiment, as shown by a two-dot chain line in FIG. 2, a first free piston 56 is slidably provided on the inner periphery of the spacer collar 45 in the front fork 4 so as to be slidable. B can be divided into upper and lower air chambers. 58 is an O-ring and 59 is a piston ring.
The first free piston 56 is connected to the air cylinder device 1 via the conduit 18 even when the hydraulic oil in the lower oil chamber C is ejected upward.
5 to prevent the air cylinder A from entering the air chamber A.
5 so as not to hinder the operation of the fifth embodiment.

According to the first embodiment, the following operations are provided. At the time of braking, the vehicle center of gravity of the motorcycle moves to the front side 1A of the vehicle body frame 1 by inertia force, and the vehicle body side inner tube 5 of the front fork 4 enters the wheel side outer tube 6. Then, the air chamber B in the front fork 4 is compressed to increase the pressure, and at the same time, the rear side 1B of the body frame 1 rises, and the swing arm 11
Rotates downward about the pivot shaft 8 (P direction in FIG. 1).

As a result, the rod 17 of the air cylinder device 15 pivotally supported by the swing arm 11 enters the cylinder 16 pivotally supported by the down tube 14 of the body frame 1, and the air chamber A in the cylinder 16 Is compressed. And
The pressure in the air chamber B in the front fork 4 communicating with the air chamber A via the conduit 18 increases. Thereby, the load moved to the front side 1A of the body frame 1 is pushed back, and the tire of the rear wheel 12 is prevented from separating from the road surface.

Conversely, during acceleration, the vehicle center of gravity moves to the rear side 1B of the vehicle body frame 1, the vehicle body side inner tube 5 of the front fork 4 retreats from the wheel side outer tube 6, and the air chamber inside the front fork 4 B expands and the pressure drops. Also, the rear side 1 of the body frame 1
B sinks, and the swing arm 11 rotates upward about the pivot shaft 8 (the Q direction in FIG. 1). As a result, the swing arm 1
The rod 17 of the air cylinder device 15 pivotally supported by 1 retreats from inside the cylinder 16, and the air chamber A in the air cylinder device 15 expands. Then, the pressure of the air chamber B in the front fork 4 communicating via the conduit 18 decreases. As a result, the vehicle center of gravity is prevented from moving to the rear side 1B of the body frame 1, and the front wheels 2 are prevented from rising.

Also, during turning, the rear side 1B of the body frame 1 sinks due to centrifugal force, and the front side 1A rises. In this case, as in the case of acceleration, the rod 17 is moved from within the air cylinder device 15 as well. Because of the retreat, the air reaction force in the front fork 4 is reduced, and the contact force and absorbency of the tire of the front wheel 2 can be increased.

When the first free piston 56 is provided in the air chamber B formed in the upper part of the front fork 4 to divide the air chamber B into upper and lower air chambers, the air chamber B is formed in the lower part of the front fork 4. The hydraulic oil in the oil chamber C is blocked by the first free piston 56, and the air cylinder device 15
Can be prevented from being mixed into the inside. This can prevent the operation of the air cylinder device 15 from being hindered.

(Second Embodiment) (FIG. 4) In the second embodiment, as shown in FIG. 4, an orifice hole 60A is formed in the inner periphery of the lower end of the cap 36 of the front fork 4 in the first embodiment. An orifice plate 60 is screwed and fixed, and a hydraulic oil is sealed in the upper part of the first free piston 56 to form a damper oil chamber D which communicates with the upper and lower portions of the orifice plate 60 via orifice holes 60A. It is. The air chamber B of the first embodiment is defined by the damper oil chamber D into an upper air chamber B1 and a lower air chamber B2.

As a result, when the swing arm 11 makes a small stroke at a high frequency, a small high-frequency pressure fluctuation also occurs in the air cylinder device 15. The pressure fluctuation in the air cylinder device 15 is transmitted to the damper oil chamber D via the conduit 18.
Of the orifice plate 60
The first free piston 56 does not move because the upper working oil is blocked by resistance when passing through the orifice hole 60A. Accordingly, the high frequency vibration of the swing arm 11 is not transmitted to the air chamber B2 below the first free piston 56, so that the front fork 4 does not vibrate minutely at high frequency.

Further, as in the first embodiment, a second free piston 63 is provided on the upper surface of the damper oil chamber D formed above the first free piston 56 as shown by a two-dot chain line in FIG. And the hydraulic oil in the damper oil chamber D does not enter the air cylinder device 15, so that the air cylinder device 1
5 does not hinder operation.

According to the second embodiment, the following operation is provided in addition to the operation of the first embodiment.

When the swing arm 11 makes a small stroke at a high frequency, a similar pressure fluctuation occurs in the air cylinder device 15. This pressure fluctuation is caused by the first free piston 5
6 and is not transmitted to the air chamber B2 below the first free piston 56. That is, the hydraulic oil above the orifice plate 60 is
Because of the resistance of the orifice hole 60A, the first free piston 56 cannot flow into the lower part of the orifice hole 60A even if a sudden pressure fluctuation occurs in the upper part of the damper oil chamber D.
Does not move. Therefore, it is possible to avoid a sudden pressure change in the air chamber B2 below the first free piston 56, and to prevent the front fork 4 from vibrating slightly.

When the second free piston 63 is provided on the upper surface of the damper oil chamber D formed above the first free piston 56, the damper oil chamber D and the air chamber B1 in the front fork 4 are partitioned. Thus, the working oil in the damper oil chamber D can be prevented from being mixed into the air chamber A in the air cylinder device 15.

(Third Embodiment) (FIGS. 5 and 6) As shown in FIGS. 5 and 6, an inverted front fork 70 with a built-in damper is used as the front fork of the first and second embodiments. Since other configurations are the same as those of the first embodiment, the same components will be described using the same reference numerals.

Since the inverted front fork 70 is also a known one, its detailed description is omitted, but the inner tube 71 forming the wheel side tube slides in the outer tube 72 forming the body side tube, and the inner tube 71 A piston rod 74 attached to the outer tube 72 is inserted into a damper cylinder 73 erected at the bottom, and a piston 75 is attached to the tip of the piston rod 74. The piston 75 is provided with an extension-side damping force generator 76, and a compression-side damping force generator 77 is provided below the damper cylinder 73. An oil chamber E communicating with an oil chamber D in the damper cylinder 73 via an oil hole 80 is provided on the outer periphery of the damper cylinder 73, and an air chamber F is provided above the oil chamber E on the outer periphery of the damper cylinder 73. .

A sub-tank 82 is mounted in front of the axle bracket 81 at the lower end of the inner tube 71 on the vehicle body side.
A third free piston 83 is slidably provided in the sub tank 82. The third free piston 83 defines an oil chamber that communicates with an oil chamber E outside the damper cylinder at the lower part and an air chamber G at the upper part. Therefore, since the air chamber G above the third free piston 83 and the upper air chamber F inside the front fork 70 are arranged with the oil chamber E outside the damper cylinder 73 interposed therebetween, the two air chambers F , G have the same pressure.

Here, as in the first embodiment, the air chamber G above the third free piston 83 is connected via the conduit 18 to
It is communicated with the air chamber A in the air cylinder device 15. still,
84 is a compression side damping force adjusting device.

The suspension device 10 of the present embodiment is
It works as follows. Air cylinder device 15 during braking
When the air chamber A is compressed, the air chamber A and the conduit 18 are compressed.
The third free piston 83 in the sub-tank 82 communicated via the lower part moves downward, raises the oil level of the oil chamber E on the outer periphery of the damper cylinder 73, and compresses the air chamber F on the upper part of the front fork. As a result, the sinking of the front side 1A of the body frame 1 is suppressed.

When accelerating or turning, the air chamber A in the air cylinder device 15 expands, the third free piston 83 in the sub tank 82 moves upward, and the oil level of the oil chamber E on the outer periphery of the damper cylinder is increased. , The volume in the air chamber F above the front fork is increased, and the reaction force is reduced.
As a result, the lifting of the front side 1A of the body frame 1 is suppressed.

Therefore, according to the third embodiment, the same operation as that of the first embodiment can be achieved.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to this embodiment, and the design can be changed within the scope of the present invention. The present invention is also included in the present invention.

[0068]

As described above, according to the present invention, during braking when the front side 1A of the body frame 1 of the motorcycle sinks, the air reaction force of the front forks 4, 70 is increased to shift the vehicle center of gravity toward the rear side. When the vehicle is accelerated while the front side 1A of the body frame 1 is floating, the front fork 4,
It is possible to provide the suspension devices 10 and 100 that improve the running stability of the motorcycle by reducing the air reaction force of 70 to prevent the center of gravity from moving to the rear side.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a motorcycle to which a suspension device of the present invention is applied.

FIG. 2 is a sectional view of an air cylinder device and an upper half sectional view of a front fork of the first embodiment.

FIG. 3 is a lower half sectional view of the front fork of the first embodiment.

FIG. 4 is an upper half sectional view of a front fork according to a second embodiment.

FIG. 5 is an upper half sectional view of a front fork according to a third embodiment.

FIG. 6 is a lower half sectional view of a front fork according to a third embodiment.

FIG. 7 is a schematic diagram showing a motorcycle in which an air cylinder device of a suspension device is directly disposed between a body frame and a swing arm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body frame 1A Front side of body frame 1B Rear side of body frame 5 Body side tube 6 Wheel side tube 10, 100 Suspension device 11 Swing arm 15 Air cylinder device 16 Cylinder 17 Rod 18 Conduit 20 Link mechanism 56 First free Piston 60 Orifice plate 63 Second free piston A Air chamber in air cylinder device B Upper air chamber in front fork C Oil chamber

Claims (4)

[Claims] 1. A front fork having a body side tube and a wheel side tube slidably fitted therein and having an air chamber formed therein is provided between a front side of a body frame and an axle of a front wheel. On the rear side, the base end of a swing arm that rotatably supports the rear wheel at the tip is swingably supported, and a hydraulic shock absorber is provided between the rear side of the body frame and the swing arm. In a suspension device for a motorcycle or the like, an air cylinder device in which a rod provided with a piston portion at a tip is slidably inserted into a cylinder and an air chamber defined between the piston portion and the cylinder is formed inside the cylinder. When the swing arm pivots downward, the rod enters the cylinder of the air cylinder device to compress the air chamber in the air cylinder device, and when the pivot arm pivots upward, The cylinder of the air cylinder device is pivotally supported on one of the vehicle body frame and the swing arm so that the rod retreats from the cylinder of the air cylinder device and the air chamber in the air cylinder device is enlarged. Wherein the rod is pivotally supported on the other of the body frame and the swing arm, and an air chamber in the air cylinder device is connected to an air chamber in the front fork via a conduit. apparatus. 2. An oil chamber is provided in a lower part of the front fork, an air chamber is provided in an upper part of the oil chamber, and a first free piston is provided in the air chamber to divide the air chamber into upper and lower air chambers. A suspension device for a motorcycle or the like according to claim 1. 3. A damper oil chamber having an orifice plate having an orifice hole formed on the inner periphery of the tube on the vehicle body above the first free piston, and communicating with the upper portion of the first free piston via the orifice hole. The suspension device for a motorcycle or the like according to claim 2, wherein the suspension device is formed. 4. The suspension device for a motorcycle or the like according to claim 3, wherein a second free piston is provided on an upper surface of a damper oil chamber formed above the first free piston.