JP2004324750A - Oil locking device of front fork of motorcycle or the like - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with an oil lock piece and to prevent noise of coming-off when shifting from a compressed state to an expansion cycle. <P>SOLUTION: In an oil locking device of a front fork 10 of a motorcycle or the like, a piston valve 20 is provided on the inner periphery at the tip of an inner tube 12. An annular inner-periphery-side flow path 33 is formed between the inner periphery of the piston valve 20 and the outer periphery of a hollow rod 16. An annular outer-periphery-side flow path 34 is formed between the outer periphery of the piston valve 20 and the inner periphery of a inner tube 12. Annular valve seats 31 and 32 to which upper and lower end faces of the piston valve 20 contacts/retracts are provided on the inner periphery at the tip of the inner tube 12. The upper/lower valve seats 31 and 32 are provided with a flow path for communicating the outer-periphery-side flow path 34 to oil chambers 21 and 22, before the outer periphery of the hollow rod 16. Notches 20 A and 20B penetrating radially are formed on the upper and lower end faces of the piston valve 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil lock device for a front fork such as a motorcycle.
[0002]
[Prior art]
As an oil lock device for a front fork of a motorcycle or the like, as described in Patent Document 1, a tapered oil hole limiting rod (oil lock piece) is abolished and close to the base of the hollow shaft 1, the axial direction of the side wall thereof A large number of small holes 2 having different hole diameters are provided at the same time, and these small holes 2 are sequentially closed by a piston body provided at the lower end of the inner tube, thereby oil-locking the oil chamber at the lower part of the piston body and buffering at the time of maximum compression. The technology which makes is disclosed.
[0003]
[Patent Document 1]
Japanese Utility Model Sho 56-119789 (1 page, Fig. 1)
[0004]
[Problems to be solved by the invention]
In the oil lock device disclosed in Patent Document 1, when moving from the most compression stroke to the extension stroke, the hydraulic oil is sufficiently contained in the oil lock oil chamber below the piston body until the piston body reaches the small hole 2 at the lowest position. When the oil lock oil chamber is not replenished and the piston body reaches a small hole 2 at the lowest position and the small hole is opened, a so-called noise (when a wine cork stopper is removed from the mouth of the bottle) A popping sound is generated.
[0005]
An object of the present invention is to eliminate an oil lock piece in an oil lock device for a front fork such as a two-wheeled vehicle and to prevent the occurrence of missing sound when shifting from the most compressed state to an extension stroke.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a hollow rod having a vehicle body side inner tube slidably fitted in a wheel side outer tube and having a partition wall portion slidably in contact with an inner periphery of the inner tube at a bottom portion of the outer tube. An oil chamber is provided on the outer periphery of the hollow rod, in which a piston valve provided on the inner periphery of the inner end of the inner tube advances and retreats, and an oil reservoir chamber in which the upper portion is an air chamber is defined on the inner periphery of the hollow rod. In an oil lock device for a front fork such as a two-wheeled vehicle provided with an oil hole communicating with the oil chamber and an oil reservoir chamber at a lower portion of the rod, the piston valve is provided on an inner periphery of a tip portion of the inner tube. An annular inner peripheral flow path is formed between the inner periphery and the hollow rod outer periphery, and an annular outer peripheral flow path is formed between the outer periphery of the piston valve and the inner tube inner periphery. Tube tip An annular valve seat in which the upper and lower end faces of the piston valve are in contact with and separated from each other is provided on the periphery, and the upper and lower valve seats are connected to the outer periphery of the hollow rod to communicate the outer peripheral flow path with the oil chamber. And a notch penetrating in the radial direction is formed on the upper and lower end faces of the piston valve.
[0007]
According to a second aspect of the present invention, in the first aspect of the present invention, further, the outer periphery of the partition wall provided in the hollow rod is opened during the compression stroke, and the oil chamber on the outer periphery of the hollow rod is opened from the oil reservoir chamber above the partition wall. And a check valve that is closed during the extension stroke and that prevents the flow from the oil chamber on the outer periphery of the hollow rod to the oil reservoir chamber above the partition wall.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an overall cross-sectional view showing a front fork, FIG. 2 shows a lower structure of the front fork, (A) is an enlarged cross-sectional view of the lower part, (B) is a cross-sectional view around the check valve, and (C) is around the piston valve FIG. 3 is a cross-sectional view showing the final stage of the compression stroke of the front fork, FIG. 4 is a cross-sectional view showing the start stage of the expansion stroke of the front fork, FIG. 5 is a piston valve, and FIG. FIG. 6B is a top view, FIG. 6C is a bottom view, FIG. 6 shows a check valve, FIG. 6A is a sectional view, FIG. 6B is a top view, and FIG.
[0009]
A front fork 10 such as a motorcycle has a vehicle body side inner tube 12 slidably fitted in a wheel side outer tube 11 as shown in FIGS. A dust seal 13 and an oil seal 14 are provided at the opening end of the outer tube 11 where the inner tube 12 is inserted.
[0010]
A bolt 15 is inserted into the bottom of the outer tube 11, and a hollow rod 16 is erected by the bolt 15. The upper end portion of the hollow rod 16 is enlarged in diameter to form a partition portion 17 that is in sliding contact with the inner periphery of the inner tube 12. In the present embodiment, a check valve 40 (described later) made of a piston ring is provided in a ring groove 17 </ b> A provided on the outer periphery of the partition wall portion 17, and the check valve 40 is slidably contacted with the inner periphery of the inner tube 12.
[0011]
A suspension spring 19 is interposed between the upper end surface of the partition wall 17 of the hollow rod 16 and the spring seat 18 provided at the upper end of the inner tube 12. The spring sheet 18 is sealed to the inner diameter of the upper end of the inner tube 12 via an O-ring 18A and is held by a stopper ring 18B.
[0012]
The front fork 10 is provided with a piston valve 20 on the inner periphery of the inner end of the inner tube 12. The upper and lower oil chambers 21 and 22 where the piston valve 20 advances and retreats are defined on the outer periphery of the hollow rod 16. The oil reservoir chamber 23 is defined as an air chamber 24, and an oil hole 25 communicating the oil chambers 21, 22 and the oil reservoir chamber 23 is provided below the hollow rod 16. The oil reservoir chamber 23 extends to the inside of the inner tube 12, and the air chamber 24 is sealed with a spring seat 18 at the upper end portion of the inner tube 12. The oil holes 25 are formed at a plurality of positions in the axial direction and the circumferential direction of the hollow rod 16.
[0013]
On the inner periphery of the distal end portion of the inner tube 12, the valve housing 30 and the upper and lower annular valve seats 31, 32 are crimped and fixed to the inner tube 12, and are slidably contacted with the hollow rod 16 inside the valve housing 30 and can move up and down 20 is built-in. The piston valve 20 may be fixed so as not to move in the vertical direction. An annular inner circumferential flow path 33 is formed between the inner circumference of the piston valve 20 and the outer circumference of the hollow rod 16, and the outer circumference of the piston valve 20 and the inner circumference of the inner tube 12 (in this embodiment, the valve housing). 30 and the inner periphery of the annular outer peripheral side flow path 34 is formed.
[0014]
The upper and lower valve seats 31, 32 are provided on the inner periphery of the inner end of the inner tube 12, and the upper and lower end surfaces of the piston valve 20 contact and separate. The upper valve seat 31 forms an upper flow path 31 </ b> A that communicates the inner peripheral flow path 33 and the outer peripheral flow path 34 with the upper oil chamber 21 between the outer periphery of the hollow rod 16. The lower valve seat 32 forms a lower flow path 32 </ b> A that communicates the inner peripheral flow path 33 and the outer peripheral flow path 34 to the lower oil chamber 22 between the lower valve seat 32 and the outer periphery of the hollow rod 16.
[0015]
As shown in FIG. 5, the piston valve 20 is provided with upper and lower notches 20 </ b> A and 20 </ b> B penetrating in the radial direction on upper and lower end surfaces contacting and separating with the upper and lower valve seats 31 and 32.
[0016]
The check valve 40 is composed of a C-shaped piston ring that is mounted in a ring groove 17A provided on the outer periphery of the partition wall 17 of the hollow rod 16 so as to be movable up and down. The check valve 40 is in sliding contact with the inner periphery of the inner tube 12, and the ring groove 17A. An annular channel 41 is formed between the bottom of the groove. As shown in FIG. 6, the check valve 40 includes a notch 40 </ b> A penetrating in the radial direction on the lower end surface of the ring groove 17 </ b> A of the partition wall 17 that contacts the lower groove side wall near the upper oil chamber 21. The check valve 40 (a) moves downward during the compression stroke (moves downward as the inner tube 12 moves relative to the hollow rod 16 downward), and the upper end surface of the check valve 40 and the ring 17 A valve is formed between the upper groove side wall of the groove 17A to open the valve, and the hydraulic oil in the oil reservoir 23 at the upper part of the partition wall 17 passes through the annular flow path 41 and the notch 40A to the outer periphery of the hollow rod 16. The upper oil chamber 21 is allowed to flow to the upper oil chamber 21. (b) During the extension stroke, the upper oil chamber 21 moves upward (the oil pressure in the upper oil chamber 21 increases and the inner tube 12 moves upward relative to the hollow rod 16). And the upper end surface of the check valve 40 is brought into close contact with the upper groove side wall portion of the ring groove 17A of the partition wall portion 17, and the hydraulic oil in the upper oil chamber 21 on the outer periphery of the hollow rod 16 is Is prevented from flowing into the oil reservoir chamber 23.
[0017]
The front fork 10 is provided with an oil hole (small hole) 26 communicating with the upper oil chamber 21 and the oil reservoir 23 in the hollow rod 16, and this oil hole (small hole) is used during the extension stroke to use the upper oil chamber 21. Based on the passage resistance of the oil flowing out from the oil reservoir chamber 23, the extension side damping force is generated.
[0018]
In the front fork 10, a rebound spring 27 at the time of maximum extension is provided between the upper valve seat 31 provided on the inner tube 12 and the partition wall 17 of the hollow rod 16.
[0019]
In the front fork 10, the impact received by the wheels is absorbed and buffered by the suspension spring 19 and the air spring of the air chamber 24, and the expansion and contraction vibration of the suspension spring 19 due to the absorption of the impact is absorbed by the oil chamber 21, Suppressed by the damping force generated at 22.
[0020]
That is, the front fork 10 performs a damping action as follows.
(Compression process)
When the inner tube 12 enters the oil chambers 21 and 22 on the outer periphery of the hollow rod 16, the pressure in the lower oil chamber 22 below the piston valve 20 whose volume is reduced increases. The piston valve 20 moves upward and contacts the upper valve seat 31. The hydraulic oil in the lower oil chamber 22 below the piston valve 20 flows into the upper oil chamber 21 through the inner peripheral flow path 33 of the piston valve 20, as well as the outer peripheral flow path 34 and the piston valve 20 of the piston valve 20. The notch 20A on the upper end surface passes through the flow path formed between the upper valve seat 31 and flows into the upper oil chamber 21 to generate a compression-side damping force.
[0021]
Since the volume of the upper oil chamber 21 above the piston valve 20 is expanded and the pressure is lowered, the check valve 40 provided in the partition wall 17 of the hollow rod 16 is opened, and the oil above the partition wall 17 is opened. The hydraulic oil in the reservoir chamber 23 flows into the upper oil chamber 21 through the annular flow path 41 and the cutout portion 40A of the check valve 40.
[0022]
Further, the hydraulic oil corresponding to the volume of entry of the inner tube 12 into the oil chambers 21 and 22 passes through the plurality of oil holes 25 formed in the lower portion of the hollow rod 16 from the lower oil chamber 22, and the inside of the hollow rod 16. It flows to the peripheral oil reservoir 23. The compression side damping force is generated by the plurality of oil holes 25.
[0023]
When the piston valve 20 sequentially closes the plurality of oil holes 25 below the hollow rod 16 and enters the final stage of the compression stroke, as shown in FIG. 3, the lower oil chamber 22 (oil lock oil chamber below the piston valve 20). The hydraulic oil 22A) passes only through the flow path formed between the inner peripheral flow path 33 and the outer peripheral flow path 34 of the piston valve 20 and the notch 20A on the upper end surface of the piston valve 20 with the upper valve seat 31. The oil flows into the upper oil chamber 21. As a result, the flow area of the hydraulic oil from the oil lock oil chamber 22A to the upper oil chamber 21 is reduced to be in an oil lock state, the compression side damping force is increased, and the outer tube 11 and the inner tube 12 are bottomed. Buffer.
[0024]
(Extension process)
When the outer tube 11 and the inner tube 12 are moved from the bottomed state to the extension stroke, the piston valve 20 moves downward and contacts the lower valve seat 32 as shown in FIG. The hydraulic oil in the upper oil chamber 21 above the piston valve 20 flows between the inner peripheral flow path 33 and the outer peripheral flow path 34 of the piston valve 20, and the notch 20 </ b> B on the lower end surface of the piston valve 20 between the lower valve seat 32. The oil lock oil chamber 22A below the piston valve 20 flows to the oil lock oil chamber 22A, smoothly eliminates the negative pressure in the oil lock oil chamber 22A, and prevents the sound from coming off during the extension stroke transition.
[0025]
Further, when the piston valve 20 is raised, the hydraulic oil in the upper oil chamber 21 above the piston valve 20 is notched in the inner peripheral side flow path 33 and the outer peripheral side flow path 34 of the piston valve 20 and the lower end surface of the piston valve 20. 20B passes through a flow path formed between the lower valve seat 32 and the lower oil chamber 22 below the piston valve 20, and flows through the oil hole (small hole) 26 formed in the upper portion of the hollow rod 16. To the oil reservoir chamber 23 on the inner periphery of the hollow rod 16. The expansion-side damping force is generated by the inner circumferential flow path 33, the outer circumferential flow path 34, and the oil hole (small hole) 26 of the piston valve 20. The oil hole (small hole) 26 may not be provided.
[0026]
According to this embodiment, there exist the following effects.
(Operational effect corresponding to claim 1)
(1) In the front fork 10, in the oil lock device for buffering at the time of the most compression, the oil lock piece can be eliminated, and when moving from the most compressed state to the expansion stroke, the inner peripheral side of the piston valve 20 Due to the presence of the flow path 33, the outer peripheral flow path 34, and the cutout portion 20B, the negative pressure in the oil lock oil chamber 22A can be smoothly eliminated to prevent the sound from coming off.
[0027]
(Function and effect corresponding to claim 2)
(2) When the front fork 10 is in the oil-locked state at the most compressed stage, the hydraulic oil in the oil-locked oil chamber 22A flows from the inner peripheral flow paths 33 and 34 of the piston valve 20 and the notch 20A on the upper end surface of the piston valve 20. It flows to the upper oil chamber 21 above the piston valve 20 through the flow path.
[0028]
Therefore, the flow path formed by the notch 20A on the upper end surface of the piston valve 20 needs to be set to a sufficiently small cross-sectional area for oil lock. However, if the notch 20A is made small, the piston will be in the normal compression stroke. When the hydraulic oil in the lower oil chamber 22 below the valve 20 flows into the upper oil chamber 21 in the upper part, the cutout portion 20A acts as an orifice, and the upper oil chamber 21 tends to be negative pressure.
[0029]
Therefore, in the present invention, a check valve 40 that opens during the compression stroke is provided in the partition wall 17 of the hollow rod 16 so that negative pressure in the upper oil chamber 21 above the piston valve 20 during the compression stroke can be prevented. However, the check valve 40 is not necessarily provided, and a piston ring may be provided instead of the check valve 40. In this case, the upper oil reservoir 23 and the lower oil chamber 21 of the partition wall portion 17 are In both the compression stroke and the expansion stroke, communication is not performed.
[0030]
In the piston valve 20, the flow passage area of the inner peripheral flow passage 33 formed by the piston valve 20 is smaller than the flow passage area formed by the notches 20A and 20B.
[0031]
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 there are design changes and the like without departing from the gist of the present invention. Is included in the present invention.
[0032]
【The invention's effect】
According to the present invention, in an oil lock device for a front fork such as a two-wheeled vehicle, the oil lock piece can be eliminated, and the occurrence of a missing sound can be prevented when shifting from the most compressed state to the extension stroke.
[Brief description of the drawings]
FIG. 1 is an overall cross-sectional view showing a front fork.
FIG. 2 shows a lower structure of the front fork, (A) is an enlarged sectional view of the lower part, (B) is a sectional view around the check valve, and (C) is a sectional view around the piston valve.
FIG. 3 is a cross-sectional view showing the final stage of the compression stroke of the front fork.
FIG. 4 is a cross-sectional view showing a start stage of a front fork extension stroke.
5A and 5B show a piston valve, where FIG. 5A is a cross-sectional view, FIG. 5B is a top view, and FIG. 5C is a bottom view.
6A and 6B show a check valve, where FIG. 6A is a cross-sectional view, FIG. 6B is a top view, and FIG. 6C is a bottom view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Front fork 11 Outer tube 12 Inner tube 16 Hollow rod 17 Bulkhead part 20 Piston valve 20A, 20B Notch part 21, 22 Oil chamber 23 Oil reservoir chamber 24 Air chamber 25 Oil hole 31, 32 Valve seat 31A, 32A In the flow path 33 Circumferential channel 34 Peripheral channel 40 Check valve

Claims (2)

The inner tube on the vehicle body side is slidably fitted into the outer tube on the wheel side,
At the bottom of the outer tube, a hollow rod provided with a partition wall slidably contacting the inner periphery of the inner tube is erected,
On the outer periphery of the hollow rod, an oil chamber in which the piston valve provided on the inner periphery of the inner end of the inner tube advances and retreats is defined,
An oil reservoir chamber with an air chamber at the top is defined on the inner periphery of the hollow rod,
In an oil lock device for a front fork such as a two-wheeled vehicle provided with an oil hole communicating with the oil chamber and the oil reservoir at the lower part of the hollow rod,
The piston valve is provided on the inner periphery of the tip of the inner tube, and an annular inner peripheral flow path is formed between the inner periphery of the piston valve and the outer periphery of the hollow rod, and the outer periphery of the piston valve and the inner An annular outer peripheral flow path is formed between the tube inner periphery,
An annular valve seat in which the upper and lower end surfaces of the piston valve are in contact with and separated from each other is provided on the inner periphery of the inner end of the inner tube, and the outer flow path is disposed between the upper and lower valve seats and the outer periphery of the hollow rod. A flow path communicating with the chamber,
An oil lock device for a front fork of a two-wheeled vehicle or the like, characterized in that a cutout portion penetrating in a radial direction is formed on the upper and lower end faces of the piston valve. A valve is opened on the outer periphery of the partition wall provided in the hollow rod during the compression stroke, allowing hydraulic oil to flow from the oil reservoir chamber above the partition wall to the oil chamber on the outer periphery of the hollow rod, and closed during the extension stroke. 2. The oil lock device for a front fork of a motorcycle or the like according to claim 1, further comprising a check valve that prevents a flow from an oil chamber on an outer periphery of the hollow rod to an oil reservoir chamber on an upper portion of the partition wall.

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