JPH0565930A - Front fork - Google Patents

Abstract

PURPOSE:To allow the inclined state of a damper cylinder to be corrected into the vertical state by forming a rod guide of a cylinder head, a float case and a float provided in the radially movable state between the cylinder head and the float case. CONSTITUTION:There are provided a cylinder head 45 for connecting the base end of a rod guide 6 to the tip of a damper cylinder 3, and a float case 47 disposed with an optional space at the outer periphery of the cylinder head 45. A float 51 is provided in the radially movable state between the outer periphery of the cylinder head 45 and the inner periphery of the float case 47. The end part of the float case 47 is engaged with the cylinder head 45, and the outer periphery of the float case 47 is brought into contact with the inner periphery of a wheel side tube 2. Accordingly, even in the case of the tip of the damper cylinder 3 being slightly inclined at the assembling time, the float 51 moves radially by this inclined part so as to enable the correction of the inclined state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front fork which is interposed between a vehicle body of a motorcycle or the like and an axle thereof to serve as a shock absorber and a fork for damping vibrations from a road surface.

[0002]

2. Description of the Related Art As a front fork of this type, for example, one disclosed in Japanese Patent Publication No. 63-154482 is known.

In this front fork, an inner tube as a wheel side tube is slidably inserted into an outer tube as a vehicle body side tube, a damper cylinder is erected from the lower center of the inner tube, and a piston is inserted through the piston in the damper cylinder. The rod is movably inserted, and the piston defines a rod-side oil chamber and a piston-side oil chamber inside the damper cylinder.The upper end of the damper cylinder is the base end of the rod guide whose outer circumference contacts the inner circumference of the inner tube. The rod guide defines an air spring chamber and an oil chamber in the upper part of the outer tube and the inner tube, and a reservoir consisting of a gas chamber and an oil chamber in the lower part, and the reservoir is provided in the lower part of the inner tube. It is connected to the piston side oil chamber via a damping force adjusting valve. .

[0004]

In the above-mentioned conventional front fork, since the base end of the rod guide is fixed to the tip of the damper cylinder and the outer periphery thereof is fixedly abutted against the inner periphery of the inner tube, the damper is formed. There is no radial relief at the tip of the cylinder.

Therefore, when the damper cylinder is assembled with a slight inclination when assembled, the inclined state cannot be corrected to the vertical state, the sliding resistance of the piston rod increases, and the smooth expansion and contraction operation is performed. can get.

Further, when the rod guide is in fixed contact with the inner circumference of the inner tube, the rigidity of the inner tube changes at the boundary of the rod guide.
The curvature due to the bending of the inner tube changes in the vicinity of the rod guide, and there is a problem that a smooth expansion and contraction operation cannot be obtained between the inner tube and the outer tube, and between the damper cylinder and the piston rod.

Therefore, an object of the present invention is to correct the tilted state when the damper cylinder is assembled to a vertical state, thereby improving the slidability of the piston rod and without changing the overall rigidity of the wheel side tube. It is to provide a front fork capable of smoothly expanding and contracting a damper cylinder and a piston rod, and a vehicle body side tube and a wheel side tube.

[0008]

In order to achieve the above object, the structure of the present invention has a cylinder head having a rod guide fixed to a damper cylinder and an arbitrary interval while engaging an end portion with the cylinder head. The float case is located on the outer circumference of the cylinder head, and the float is provided between the outer circumference of the cylinder head and the inner circumference of the float case so as to be movable in the radial direction. It is characterized by being brought into contact with.

[0009]

When the tip of the damper cylinder is slightly inclined during assembly, the float moves in the radial direction by the amount of inclination, so the inclination state can be corrected, and an unreasonable load is not applied to the float case. When the piston rod is connected to the vehicle body side tube even if the damper cylinder is slightly inclined,
Alternatively, during the expansion and contraction operation, the damper cylinder is corrected while moving the float in the vertical direction in the opposite direction, and does not adversely affect the slidability.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment in which a gas filling valve is connected to the damping force adjusting valve to fill the gas in the gas chamber and the rod guide has a floating structure.

A wheel side tube 2 is slidably inserted into a vehicle body side tube 1, a damper cylinder 3 stands up from the lower center of the wheel side tube 2, and a piston rod 5 is inserted in the damper cylinder 3 via a piston 4. Is movably inserted, and the tip of the piston rod 5 is connected to the vehicle body side tube 1 via a cap 7.

A base end of a floating rod guide 6 is coupled to the tip of the damper cylinder 3, and the outer periphery of the rod guide 6 abuts the inner periphery of the wheel side tube 2,
A hollow piston rod 5 is slidably fitted in the center of the rod guide 6.

The piston 4 defines an upper rod-side oil chamber 8 and a lower piston-side oil chamber 9 in the damper cylinder 3, and the two oil chambers 8 and 9 are ports 1 provided in the piston 4.
7, 18 and a passage 19 provided at a lower portion of the piston rod 5 and communicating with a check valve 20 provided at the outlet ends of the ports 17 and 18 and an extension damping valve 21, and an opening area of the passage 19 is adjusted. It communicates via the needle valve 22.

The needle valve 22 is moved and operated by a control rod 55 inserted in the piston rod 5.

The rod guide 6 defines an air spring chamber 13 above the wheel side tube 2 and the vehicle body side tube 1, and a reservoir 12 consisting of a gas chamber 10 and an oil chamber 11 below the wheel side tube 2. There is. Oil may be sealed below the air chamber 13.

A spring seat 24 is connected to an upper portion of the rod guide 6 via a seal case 23 which also serves as a screw cylinder, and a suspension for urging the vehicle body side tube 1 in the extending direction is provided between the spring seat 24 and the cap 7. Spring 14
Is installed.

A compression side damping force generating device 15 is provided below the damper cylinder 3, a compression side damping force adjusting valve 16 is provided at a bottom member 25 which is a lower portion of the wheel side tube 2, and a piston side oil chamber 9 and a reservoir 12 are provided. Communicate with the compression-side damping force generator 15 via the compression-side damping force adjusting valve 16.

The compression side damping force generator 15 includes a valve body 27 fastened by a bolt 26, a piston 28 provided on the valve body 27, a compression side damping force valve 32 provided at the outlet ends of the ports 29 and 30 of the piston 28, and It is composed of a check valve 31.

The oil in the piston side oil chamber 9 is compressed to the port 29 during compression.
From the pressure side damping valve 32 to open the pressure side damping valve 32 to the reservoir 12 through the oil hole 36 of the wheel side tube 2, and at this time the damping side damping valve 32 generates a damping force. It opens and is sucked into the piston side oil chamber 9.

Axial passages 33 and 35 are formed in the valve body 27 and the bolt 26, and a check valve 34 is provided in the passage 33 so as to be openable and closable.
Reference numeral 5 connects the piston side oil chamber 9 to the compression side damping force adjusting valve 16.

The compression damping force adjusting valve 16 includes a hollow valve housing 37, ports 38 and 39 formed in the valve housing 37, and a needle valve 4 for opening and closing the port 38.
0 and a hollow adjuster 42 deformably coupled to the needle valve 40. When the adjuster 42 is rotated from the outside, the needle valve 40 advances and retreats while rotating along the screw of the valve housing 37 to reduce the opening area of the port 38. To adjust.

During the compression operation, the oil in the piston side oil chamber 9 flows out from the passage 33.35 to the reservoir 12 via the needle valve 40, the ports 38, 39 and the oil passage 44 of the bottom member 25, and is throttled by the needle valve 40. The compression side damping force is generated according to the area.

A gas charging valve 41 is provided in the adjuster 42.
When a gas such as pressurized air or gas is supplied from the gas sealing valve from the outside as needed, the gas is supplied to the port 39 through a passage such as a notch or a hole provided in the needle valve. It is led to the reservoir 12 from the passage 44,
It is guided from the oil chamber 11 to the gas chamber 10.

Therefore, the gas chamber 10 is pressurized, and the oil chamber 11, the rod-side oil chamber 8 and the piston-side oil chamber 9 are also pressurized by this, and the air chamber is not mixed in the oil in each oil chamber. Therefore, the decrease and instability of the damping force during the expansion and contraction operation are prevented.

As shown in FIG. 3, the rod guide 6 includes a cylinder head 45 and an outer peripheral annular groove 4 of the cylinder head 45.
6, a float case 47 provided at an arbitrary interval while being opposed to 6, and a cylinder head 45 and a float case 47.
And a float 51 which is located between and and is movable in the annular groove 46 while floating in the radial direction.

The nut 52 is attached to the bottom of the float case 47.
This nut 52 has a rotation stopper protrusion 52a on the inner circumference.
The protrusion 52a engages with the edge of the cylinder head 45 to prevent the float case 47 from rotating.

The nut 52 pushes the float 51 in the axial direction, and seals 53, 53 are provided on the upper surface and the inner surface of the float 51.
And these seals 53, 53 separate the upper air spring chamber 13 from the lower reservoir 12.

A frustoconical taper 54 is formed on the upper side of the seal case 47, and a seal 50 composed of an annular O-ring abuts on the taper 54. The seal 50 is fitted with a flanged bolt 49 via a washer 48. The seal 50 is fastened by the wheel tube 2 and the float case 4
It seals between 7 and.

The taper 54 guides the seal 50 when the seal 50 is tightened, and prevents damage during movement.

A through hole 55 is formed in the wheel tube 2 so that the inside and outside communicate with each other and through which oil flows.

At the time of assembling the front fork, first, the wheel side tube 2 and the damper cylinder 3 are filled with oil,
Then, from the vehicle body side tube 1 side to the oil chamber 11 of the reservoir 12
The volume of the gas chamber 10 is set to the design volume with the oil level of the side facing.

On the other hand, with the float case 47 and the float 51 attached to the outer periphery of the cylinder head 45, the cylinder head 45 is inserted from above the inside of the tube 1 on the vehicle body side, and its base end is screwed onto the upper portion of the damper cylinder 3.

Further, the seal 50 is inserted and tightened with the washer 48 and the bolt 49.

At the time of the above-mentioned assembly, the cylinder head 4
Since the float 51 and the seal 50 pass through the through hole 55 and move in the direction of the gas chamber 10 at the time of assembling 5 and the seal 50, the gas chamber 10 can be pressurized by the moving stroke of these members.

The float 51 is movable in the radial direction along the float case 47 and the nut 52 to correct the inclination of the damper cylinder 3 at the time of assembly or when an external force acts and change the rigidity of the wheel side tube 2. To prevent it.

Reference numeral 56 is a bearing, 57 is a cushion spring, and 58 is a return spring of the needle valve 22.

FIG. 4 shows another embodiment relating to the mounting position of the gas charging valve, and the gas chamber 10 and the rod guide 6 are shown in FIG.
The same as the embodiment of

The gas filling valve 59 is composed of a hollow valve case 60 provided in the bottom portion 25 so as to open in the reservoir 12 in the radial direction, and a filling valve 61 provided in the valve case 60. The gas chamber 10 is pressurized by directly supplying air, gas or the like into the reservoir 12 from 61 as necessary.

In the above embodiment, the damping force adjusting valve 17 is a normal valve and the adjuster 42a is a solid body.

Since the gas sealing valve 59 is provided on the bottom member 25, it does not interfere even when the vehicle body side tube 1 is lowered to the maximum compression.

FIG. 5 shows another embodiment relating to the mounting position of the gas sealing valve, and the other structures such as the rod guide 6 are the same as the embodiment of FIG.

In this embodiment, the gas sealing valve is provided with the cap 7.
The gas such as air and gas supplied from the gas sealing valve is introduced into the gas chamber 10 through the piston rod 5.

A rotating body 63 is rotatably inserted into the cap 7, a spring holder 62 is vertically movable between the cap 7 and the rotating body 63, and the rotating body 63 is interlocked with a spring adjuster 72. ..

When the adjuster 72 rotates, the rotating body 63 rotates, and at this time, the spring holder 62 engaged with the key 73 moves vertically, and the initials of the suspension spring 14 are adjusted via the spacers 67 and 68.

A housing 70 also serving as an adjuster is provided in the spring adjuster 72, and a gas sealing valve 71 is provided in the housing 70.

A slider 64 is vertically movably inserted in the center of the rotating body 63, the slider 64 abuts on a needle valve control rod 65 in the piston rod 5, and a passage 69 provided in the slider 64 is filled with gas at one end. The gas chamber 1 is opened through the passage 66 in the piston rod 5 and the downward radial passage 67 while opening to the valve 71.
It is connected to 0.

When the housing 70 is rotated, the slider 6
4 moves up and down, and the movement is transmitted to the needle valve 22 via the control rod 65.

When gas is introduced from the gas charging valve 71, it is supplied to the gas chamber 10 through the passage 69-passage 66-passage 67 to pressurize the gas chamber 10 as needed.

[0050]

The present invention has the following effects.

Since the rod guide is composed of the cylinder head and the float case, and the float provided between the cylinder head and the float case so as to be movable in the radial direction,
Even when the damper cylinder is slightly tilted when assembled, the float moves by this tilt, no unreasonable load is applied to the float case, and the tilted state of the damper cylinder can be corrected to the vertical state.

Since an unreasonable load does not act on the float case, the rigidity of the wheel side tube with which the float case abuts does not increase only near the rod guide. Therefore, the curvature due to the bending of the wheel side tube during traveling is uniform and a smooth expansion and contraction operation can be performed between the vehicle body side tube and the wheel side tube.

If the piston rod is vertical when the piston rod is attached to the vehicle body side tuft or while traveling, the float moves in the direction opposite to the above, and the damper cylinder can be corrected to the vertical state, and the piston rod can move smoothly. You can perform flexible expansion and contraction.

[Brief description of drawings]

FIG. 1 is a partially cutaway vertical front view of a device front fork according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of FIG.

3 is a partially enlarged cross-sectional view of FIG.

FIG. 4 is a partially cutaway vertical front view of a front fork according to another embodiment of the present invention.

FIG. 5 is a partially cutaway vertical front view of a front fork according to another embodiment of the present invention.

[Explanation of symbols]

 1 Body Side Tube 2 Wheel Side Tube 3 Damper Cylinder 4 Piston 5 Piston Rod 6 Rod Guide 7 Cap 8 Rod Side Oil Chamber 9 Piston Side Oil Chamber 10 Gas Chamber 11 Oil Chamber 12 Reservoir 13 Air Spring Chamber 14 Suspension Spring 45 Cylinder Head 47 Float case 51 float

Claims (1)

[Claims] 1. A wheel side tube is slidably inserted into a vehicle body side tube, a damper cylinder is erected from the lower center of the wheel side tube, and a piston rod is movably inserted into the damper cylinder via a piston. The piston divides the rod-side oil chamber and the piston-side oil chamber in the damper cylinder, the base end of the rod guide is attached to the tip of the damper cylinder, and the outer circumference of this rod guide is set to the inner circumference of the wheel side tube. In contact with each other, the rod guide is partitioned into an air spring chamber and a reservoir composed of a gas chamber and an oil chamber in the wheel side tube, and a suspension spring is interposed between the rod guide and the tip cap of the vehicle body side tube. In the front fork, the rod guide is attached to the cylinder head in which the base end is joined to the tip of the damper cylinder, and It is composed of a float case arranged at an arbitrary interval and a float provided between the outer circumference of the cylinder head and the inner circumference of the float case so as to be movable in the radial direction, and the end of the float case is engaged with the cylinder head. A front fork characterized in that the outer periphery of the front fork is brought into contact with the inner periphery of the wheel side tube.