JP2001263405A - Hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of part items, and to vary the damping force generated in a low speed range of a piston in a hydraulic shock absorber which can increase the damping force in the initial operation of the piston. SOLUTION: In the hydraulic shock absorber 10 having damping force generating valves 40 (50, 60) and damping force variable valves 70 (80, 90), the damping force generation valve 50 comprises a first subdisk valve 51 having an orifice 51A, a second subdisk valve 52, a subvalve seat 53, main disk valves 54-56, a main valve seat 57, and a ring 58 having a slit 58A and a flange portion 58B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hydraulic shock absorber.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic shock absorber capable of increasing a damping force in an early stage of operation of a piston, there is one disclosed in Japanese Utility Model Publication No. 5-38258. In this hydraulic shock absorber, a piston rod is inserted into a cylinder, a piston-side oil chamber and a rod-side oil chamber are partitioned into a piston-side oil chamber and a rod-side oil chamber within the cylinder by a piston provided on the piston rod. And a damping force generating valve device for controlling the flow of hydraulic oil in the oil passage to generate a damping force. The damping force generating valve device is provided in a first disc valve provided so as to close an oil passage of the piston, and formed with a passage facing the oil passage and communicating between the front and back, and a first disc valve. A second disk valve that abuts and closes the passage; a third disk valve that is disposed with a retainer interposed between the second disk valve and a peripheral side of the first disk valve and the third disk valve; A ring is provided and forms a space that allows the deflection of the second disk valve, and a slit is formed in the third disk valve and communicates the space with the cylinder chamber.

According to this configuration, at the initial stage of the operation of the piston, the hydraulic pressure in the oil passage is small, so that the passage of the first disk valve remains closed by the second disk valve, so that a high damping force can be obtained. . When the operating speed of the piston increases, the second disc valve opens the passage, and the oil in the oil passage flows through the gap from the passage of the third disc valve to the cylinder chamber. At this time, the orifice characteristic is obtained by one of the passages (the passage having the smaller opening area).

Further, when the piston speed increases, the first to
The third disk valve bends to obtain valve characteristics by the disk valve.

[0005] Conventionally, as a hydraulic shock absorber provided with a damping force variable valve device for varying the damping force of the hydraulic shock absorber,
There is one described in Japanese Utility Model Publication No. 5-23864. In this hydraulic shock absorber, in addition to providing a damping force generating valve device in a main oil passage provided in a piston, an opening area of a bypass oil passage that bypasses the main oil passage can be adjusted by a needle valve. At this time, the hydraulic shock absorber includes a sub-valve mechanism for providing a sub-valve (check valve) in the bypass oil passage, and the sub-valve mechanism is provided on a stud separate from the piston.

[0006]

[Problems to be solved by the invention]
The prior art described in Japanese Patent No. 38258 has the following problems.

A ring is interposed between the first disk valve and a ring to form an interval, and a third disk valve having a slit communicating the interval with the cylinder chamber, that is, a disk valve with a slit is provided in addition to the ring. Required, and the number of parts increases.

The damping force generated in the low speed range of the piston cannot be made variable.

The above-mentioned ring is sandwiched between the first disk valve and the third disk valve, and has a small radial gap with the outer periphery of the second disk valve so as to allow the second disk valve to bend. Need to go through. Also,
With the first disc valve closed, the third disc valve may open, in which case the ring also has an axial clearance between them. For this reason, the ring floats in the radial direction without the centering means in the radial direction, and also moves in the axial direction.

[0010] The prior art described in Japanese Utility Model Publication No. Hei 5-23864 has the following problems. A sub-valve mechanism is required separately from the piston, and the number of parts increases.

A space for disposing the sub-valve mechanism is required separately from the piston, and the damping force generating mechanism becomes longer in the axial direction.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic shock absorber capable of increasing a damping force in an early stage of operation of a piston, in which the number of parts can be reduced and a damping force generated in a low-speed range of the piston is made variable.

Another object of the present invention is to simply and fixedly arrange a ring for allowing the second sub-disc valve to bend so as to open and close the orifice of the first sub-disc valve at the beginning of operation of the piston.

[0014]

According to the present invention, a piston rod is inserted into a cylinder, and a piston-side oil chamber and a rod-side oil chamber are defined in the cylinder by a piston provided on the piston rod. A main oil passage that enables the piston-side oil chamber and the rod-side oil chamber to communicate with the piston,
A damping force generating valve device for controlling a flow of hydraulic oil in the main oil passage to generate a damping force, wherein the piston rod bypasses a main oil passage provided in the piston and a piston-side oil chamber and a rod. A bypass oil passage that allows communication with the side oil chamber, and a damping force variable valve that controls a flow of hydraulic oil in the bypass oil passage to generate a damping force by adjusting an opening area of the bypass oil passage. A hydraulic shock absorber comprising: a damping force generating valve device, wherein the damping force generating valve device opens both a main oil passage and a bypass oil passage of a damping force variable valve device on a piston round surface of the piston; A main oil passage that opens to the round surface is provided to open and close, and communicates with a bypass oil passage of the variable damping valve device that opens to the piston round surface of the piston. A first sub-disc valve having a orifice, a second sub-disc valve in contact with the first sub-disc valve and closing the orifice, a sub-valve seat in contact with the second sub-disc valve, and a sub-valve seat. A main disk valve that abuts, a main valve seat that abuts the main disk valve, and a space that is interposed between the first sub disk valve and the main disk valve to form a space that allows the second sub disk valve to bend; And a ring having a slit communicating the oil chamber in the cylinder with the interval.

According to a second aspect of the present invention, in the first aspect of the present invention, the total flow area of the slit provided in the ring is further reduced by the total flow area of the orifice provided in the first sub-disc valve. It is intended to be larger.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the ring further includes a flange portion which comes into contact with the outer periphery of the main disk valve.

[0017]

According to the first aspect of the present invention, the following effects are obtained. In the initial stage of the operation of the piston, both the oil pressure in the main oil passage of the piston and the oil pressure in the bypass oil passage of the variable damping valve device are small, so that the oil passage of the piston remains closed by the first sub-disc valve, In addition, since the orifice of the first sub-disc valve communicating with the bypass oil passage of the variable damping force valve device is kept closed by the second sub-disc valve, a high damping force can be obtained. When the operating speed of the piston increases to some extent and reaches a low speed range, the second sub-disc valve is bent to open the orifice, and the hydraulic oil in the bypass oil passage of the variable damping force valve device passes through the orifice to slit the ring. To the oil chamber of the cylinder, the damping force set in the damping force variable valve device and the damping force due to the bending of the second sub-disk valve are obtained. At this time, the second sub-disc valve may have only a check valve function and may not generate a damping force.

When the operating speed of the piston further increases and reaches a middle to high speed range, the first sub-disc valve and the main disc valve are bent and opened with the ring interposed therebetween, and the operating oil in the main oil passage of the piston communicates with the piston. Flows from the gap formed between the first sub-disc valves to the oil chamber of the cylinder,
The damping force due to the bending of the first sub disk valve and the main disk valve is obtained. This damping force can be changed by stacking a plurality of main disk valves. At this time, the second sub-disc valve closes the orifice of the first sub-disc valve, and the hydraulic oil in the bypass oil passage of the variable damping valve device is filled with the aforementioned gap formed between the piston and the first disc valve. From the cylinder to the oil chamber of the cylinder.

Since the ring is provided with a slit communicating the oil chamber in the cylinder with a gap formed between the first sub-disk valve and the main disk valve,
It is not necessary to provide a disk valve with a slit in addition to the ring, and the number of parts can be reduced.

By providing the above-described variable damping force valve device, the damping force generated in the low speed range of the piston can be changed.

A bypass oil passage of the variable damping force valve device is opened on the piston round surface of the piston, and a first sub-disc valve and a second sub-disc valve constituting a sub-valve mechanism for opening and closing this bypass oil passage are used as main disc valves. Since they are stacked, there is no need to provide a sub-valve mechanism separate from the piston, and the number of parts can be reduced.

Since there is no need to provide a sub-valve mechanism separately from the piston, no space is required for disposing the sub-valve mechanism, and the damping force generating mechanism can be made compact.

According to the second aspect of the invention, the following effects are obtained. The total flow passage area of the slit provided in the ring was made larger than the total flow passage area of the orifice provided in the first sub-disk valve. Therefore, the interval formed by the ring between the first sub-disc valve and the main disc valve always communicates with the oil chamber of the cylinder through the large opening slit, and the oil pressure within this interval does not rise, Does not open the main disc valve alone. That is, the first sub-disc valve and the main disc valve always stably fix the ring in the axial direction without any gap, thereby preventing the ring from dropping and generating abnormal noise.

According to the third aspect of the invention, the following effects are obtained. The ring can be centered by abutting the flange portion of the ring against the outer periphery of the main disk valve, and the ring can be positioned and fixed without always moving in the radial direction, thereby preventing the ring from falling off and generating abnormal noise.

When the ring is not provided with a collar,
Another radial positioning means may be provided on the ring, or the inner circumference of the ring may be brought into contact with the outer circumference of the second disc valve to center the ring.

The centering of the ring is performed by the outer periphery of the main disk valve by the collar portion of the ring, and is not performed by the outer periphery of the second sub disk valve. Therefore, the radial size of the second sub disk valve can be freely changed ( The thickness can also be changed), and the above-described bending force and opening timing of the second sub-disc valve can be freely set to adjust the damping characteristics.

If the flange of the ring is continuous over the entire circumference, the height of the slit provided in the ring can be made equal to the total thickness of the second sub-disc valve and the sub-valve seat, and the total flow path of the aforementioned slit can be obtained. Since the area can be made larger, it is possible to reliably fix the ring in the axial direction as described above.

[0028]

FIG. 1 is a sectional view showing a hydraulic shock absorber.
FIG. 2 is an enlarged sectional view showing the damping force adjuster device of FIG. 1,
3 is an enlarged sectional view showing the valve device of FIG. 1, FIG. 4 is a schematic view showing the damping force generating valve device taken out, FIG. 5 is a plan view showing a ring, and FIG. 6 shows a modified example of the damping force generating valve device. FIG.

As shown in FIG. 1, the hydraulic shock absorber 10 has a cylinder 11, a piston rod 12, and a suspension spring 13. A lower spring seat 14 and a lock nut 15 are attached to the outer periphery of the cylinder 11, and the piston rod An upper spring seat 16 and a lock nut 17 are attached to a vehicle body-side mounting portion 20 screwed to the screw 12, and a suspension spring 13 is interposed between the lower spring seat 14 and the upper spring seat 16. The set length of the suspension spring 13 can be adjusted by screwing the spring seats 14 and 16 with respect to the cylinder 11.

The hydraulic shock absorber 10 includes an axle-side mounting portion 18 and a lock nut 19 screwed to a lower portion of the cylinder 11, and a vehicle-body-side mounting portion 20 screwed to an upper end portion of the piston rod 12. The suspension spring 13 absorbs the impact from the road surface, and the cylinder 11 incorporates a damping force generation valve device 40 and a damping force variable valve device 70 described later to dampen the expansion and contraction vibration of the suspension spring 13.

The hydraulic shock absorber 10 has a rod guide 21 for supporting the piston rod 12. The rod guide 21 is inserted into the cylinder 11 via an O-ring 22 and is prevented from coming off by a stopper ring 23.
The piston rod 12
Are slidable in a liquid-tight manner.

The hydraulic shock absorber 10 fills the cylinder 11 with hydraulic oil and makes a piston 27 provided on a piston bolt 26 integral with the piston rod 12 slidable. The piston 27 includes a piston-side oil chamber 28A that does not accommodate the piston rod 12 inside the cylinder 11,
A rod-side oil chamber 28B for accommodating the piston rod 12 is defined.

In the present embodiment, the hydraulic shock absorber 10 is of a single tube separation pressurizing type, in which a free piston 29 (O-ring 29A) is slidably disposed inside the cylinder 11, and the piston-side oil is moved by the free piston 29. Room 2
8A and a pressurized gas chamber 30 are defined. Hydraulic shock absorber 1
Reference numeral 0 denotes a gas sealing cap 31 for sealing a pressurized gas into the pressurized gas chamber 30, which is inserted into the cylinder 11 via an O-ring 32, and is prevented from coming off by a stopper ring 33. The free piston 29 moves during the compression stroke and the extension stroke of the hydraulic shock absorber 10 and absorbs a change in volume of the piston rod 12 that enters or leaves the cylinder 11.

The cylinder 11 has a bump stopper cap 34 outside the rod guide 21. At the time of maximum compression, the bump rubber 35 of the piston rod 12 abuts the stopper cap 34 to regulate the maximum compression stroke. . The cylinder 11 has a rebound rubber 37 at the inner end of the rod guide 21 via a washer 36. When the cylinder 11 is extended, the rebound rubber 37 abuts against a rebound stopper 38 of the piston bolt 26 to regulate the maximum extension stroke. I do.

The hydraulic shock absorber 10 includes a damping force generation valve device 40 (extension side damping force generation valve device 50 and a compression side damping force generation valve device 60) and a damping force variable valve device 70 (extension side damping force variable valve device 80). And a compression-side damping force variable valve device 90). The damping force generated by these valve devices 40 and 70 suppresses the expansion and contraction vibration of the cylinder 11 and the piston rod 12 due to the absorption of the shock by the suspension spring 13.

(Damping Force Generating Valve Device 40) (FIGS. 1, 3 to 5) The damping force generating valve device 40 is screwed to the end of the piston rod 12 inserted into the cylinder 11, as shown in FIG. Compression-side damping force generating valve device 6
0, the piston 27, the extension side damping force generating valve device 50, and the valve stopper 41 are inserted and fixed with a nut 42. At this time, the piston 27 is
A, the interior of the cylinder 11 is slid in contact with the piston ring 43B, and the piston side oil chamber 28A and the rod side oil chamber 28B
The main oil passage 44 and the main oil passage 45 are provided. Each of the expansion-side main oil passage 44 and the compression-side main oil passage 45 is provided with a later-described expansion-side bypass oil passage 72 of the expansion-side damping force variable valve device 80 and a later-described compression-side bypass oil passage 74 of the compression-side damping force variable valve device 90. , Piston 27
The upper and lower pistons are open on the round surface. In the present embodiment, the main oil passages 44 and 45 are opened radially outside the piston round surface, and the bypass oil passages 72 and 74 are opened radially inside the piston round surface.

The expansion-side damping-force generating valve device 50 is arranged on the side of the piston 27 facing the piston-side oil chamber 28A, and by closing the expansion-side main oil passage 44, generates an expansion-side damping force at the time of expansion. . Compression side damping force generating valve device 60
Is arranged on the side of the piston 27 facing the rod-side oil chamber 28 </ b> B, and generates a compression-side damping force during compression by closing the compression-side main oil passage 45.

As shown in FIG. 4, the expansion-side damping-force generating valve device 50 includes a first sub-disc valve 51, a second sub-disc valve 52, a sub-valve seat 53, and first to third main disc valves 54 to 56. , A main valve seat 57 and a ring 58. The first sub-disc valve 51 is provided to open and close the extension-side main oil passage 44 that opens on the piston round surface of the piston 27, and the extension-side damping force variable valve device 80 that opens on the piston round surface of the piston 27. An orifice 51A that communicates with a later-described bypass oil passage 72 is provided. The second sub disc valve 52 contacts the first sub disc valve 51 and closes the orifice 51A. The sub valve seat 53 contacts the second sub disc valve 52. The first main disc valve 54 contacts the sub-valve seat 53, and the second and third main disc valves 55,
Reference numeral 56 is stacked on the first main disk valve 54. The main valve seat 57 contacts the third main disc valve 56. The ring 58 is interposed between the first sub-disc valve 51 and the first main disc valve 54 to form a gap 59 that allows the second sub-disc valve 52 to bend, and the gap 59 is formed by the piston-side oil chamber 28. Are provided at a plurality of positions in the circumferential direction.

At this time, the extension side damping force generating valve device 50
Then, the total flow passage area of the slit 58 </ b> A provided in the ring 58 is changed to the orifice 5 provided in the first sub-disk valve 51.
1A to avoid an increase in the oil pressure at the interval 59, and the oil pressure at the interval 59
It prevents that only ~ 56 is opened.

As shown in FIGS. 4 and 5, the ring 58 is provided with a brim portion 58B which is continuous around the entire circumference.
8B is brought into contact with the outer periphery of the first main disc valve 54, whereby the ring 58 is centered and can be positioned and fixed.

As shown in FIG. 3, the compression-side damping-force generating valve device 60 is configured in exactly the same manner as the extension-side damping-force generating valve device 50. 2 Sub disk valve 52, sub valve seat 53, first to third main disk valves 54 to 56, main valve seat 57, first sub disk valve 61 similar to ring 58, second sub disk valve 62, sub valve Seat 63, first to third main disc valves 64-66, main valve seat 67,
A ring 68 is provided, forming an interval 69 similar to the interval 59. The first sub disc valve 61 has an orifice 61 similar to the orifice 51A of the first sub disc valve 51.
A, and the ring 68 is provided with a slit 58 of the ring 58.
A, a slit 68A and a flange 68 similar to the flange 58B.
B is provided.

(Variable Damping Force Valve Device 70) (FIGS. 1 to 3) The variable damping force valve device 70 is provided on each of the piston bolt 26 and the piston 27 integral with the piston rod 12 and the extension provided on the piston 27. The piston side oil chamber 28A and the rod side oil chamber 28B
And a compression-side bypass oil passage that connects the piston-side oil chamber 28A and the rod-side oil chamber 28B by bypassing the compression-side main oil passage 45 provided in the piston 27. Each of the paths 73 and 74 is provided. The extension bypass oil passage 72 provided in the piston 27 opens to the piston round surface of the piston 27 as described above, and communicates with the orifice 51A of the first sub-disc valve 51 of the extension damping force generating valve device 50. The pressure-side bypass oil passage 74 provided in the piston 27 opens to the piston round surface of the piston 27 as described above, and communicates with the orifice 61A of the first sub-disc valve 61 of the pressure-side damping force generating valve device 60.

The variable damping force adjusting valve device 80 is provided with a damping force adjusting rod 8 operated by the expanding adjuster device 81.
2 advances and retreats in the hollow portion of the piston rod 12 (piston bolt 26), and the needle valve 83 at the tip of the damping force adjusting rod 82 opens the extension side bypass oil passage 71 (valve seat 71 A) provided in the piston bolt 26. By adjusting the area, the flow of the hydraulic oil in the expansion side bypass oil passages 71 and 72 is controlled to generate the expansion side damping force during expansion. The compression-side damping force variable valve device 90 is configured such that the damping force adjustment rod 92 operated by the compression-side adjuster device 91 is connected to the piston rod 1.
2 (the damping force adjusting rod 82, the piston bolt 26) moves forward and backward in the hollow portion, and the needle valve 93 at the tip of the damping force adjusting rod 92 causes the pressure side bypass oil passage 73 (the valve seat 73A) provided in the piston bolt 26 to move. By adjusting the opening area, the flow of hydraulic oil in the compression-side bypass oil passages 73 and 74 is controlled to generate a compression-side damping force during compression.

The orifices 51A, 61A of the first sub-disc valves 51, 61 are connected to the variable damping force valve device 8.
The bypass oil passages 71 and 73 of 0 and 90 are set as follows. Needle valve 8 for bypass oil passages 71 and 73
3 and 93, the orifices 51A and 61A of the first sub-disc valves 51 and 61 are fully opened.
Then, the orifices 51A, 61A of the first sub-disc valves 51, 61 have a flow passage area larger than the bypass oil passages 71, 73 of the damping force variable valve devices 80, 90 so as not to perform the throttling action.

As shown in FIG. 2, the expansion-side adjuster device 81 of the expansion-side damping force variable valve device 80 fixedly inserts the operating rod 85 to which the dial 84 is fixed to the upper end of the hollow portion of the piston rod 12. The operating rod 85 is rotatably inserted into the stopper 12A, and the lower end of the operating rod 85 is connected to the upper end of the damping force adjusting rod 82 so as to be integrally rotatable only in the rotational direction. At this time, the damping force adjusting rod 82
It is screwed into the inner periphery of the hollow part of the piston rod 12,
The hollow portion of the piston bolt 26 is slid in a liquid-tight manner through the O-ring 82A by being rotated by the extension side adjuster device 81, and the needle valve 83 at the tip is brought into contact with and separated from the valve seat 71A of the extension side bypass oil passage 71. Adjust the opening area. The dial 84 is disposed in a window-shaped cavity 20A provided in the vehicle body-side mounting member 20 and is rotatable. The dial 84 is provided with a ball (not shown) at a plurality of positions in the circumferential direction of the stopper 12A. Each of them is sequentially engaged, and the setting is changed with a sense of moderation at each of the plurality of rotation operation stop positions.

As shown in FIG. 2, the pressure-side adjuster device 91 of the pressure-side damping force variable valve device 90 rotatably inserts the operation rod 95 to which the dial 94 is fixed into the hollow portion of the operation rod 85 described above. The distal end of the operating rod 95 is connected to the upper end of the damping force adjusting rod 92 so as to be integrally rotatable only in the rotational direction. At this time, the damping force adjusting rod 92 is screwed into the inner periphery of the hollow portion of the operating rod 85, and is rotated by the compression side adjuster device 91 so that the hollow portion of the damping force adjusting rod 82 and the hollow portion of the piston bolt 26 are rotated. O-rings 92A, 92
The needle valve 93 at the distal end slides in a liquid-tight manner through B, and comes into contact with and separates from the valve seat 73A of the pressure-side bypass oil passage 73 to adjust the opening area thereof. The dial 94 is attached to the vehicle body-side mounting member 20.
In the window-shaped hollow portion 20A provided on the dial 94, the engagement concave portion is arranged in parallel with the dial 84 so as to be rotatable, and the balls 96 built in the dial 84 are arranged at a plurality of circumferential positions on the end face of the dial 94. Are sequentially engaged, and the setting is changed with a sense of moderation at each of the plurality of rotation operation stop positions.

In the extension-side adjuster device 81, when only the dial 84 is operated to rotate, not only does the extension-side damping force adjusting rod 82 move forward and backward, but also the compression-side damping force screwed to the operating rod 85. The adjustment rod 92 also moves forward and backward. Accordingly, when the extension side adjuster device 81 is used, the dial 84 and the dial 94 are grasped together and simultaneously rotated to prevent the compression side damping force adjustment rod 92 from unexpectedly moving back and forth, and the extension side damping force adjustment rod 8
Only 2 can advance and retreat. In addition, the compression-side adjuster device 91
In use, only the dial 94 on the pressure side is rotated.

Accordingly, the hydraulic shock absorber 10 performs a damping action as described below by the damping force generating valve device 40 and the damping force variable valve device 70 described above.

When the operating speed of the piston 27 is low, the oil pressure in the rod-side oil chamber 28B is adjusted by the needle valve 83 of the variable-side damping force variable valve device 80 through the expansion-side bypass oil passages 71 and 72. The orifice 51A of the first sub-disc valve 51 of the extension side damping force generating valve device 50
And the second sub-disc valve 52 is bent and pushed open, and flows from the space 59 between the first sub-disc valve 51 and the first main disc valve 54 to the piston side oil chamber 28A via the slit 58A of the ring 58. . Thereby, the needle valve 83 of the extension-side damping force variable valve device 80 is
Force due to throttle resistance of the second sub-disc valve 5
A damping force due to the deflection resistance of 2 is obtained.

When the operating speed of the piston 27 is medium or high,
The oil pressure in the rod-side oil chamber 28B acts on the first sub-disk valve 51 of the expansion-side damping force generating valve device 50 from the expansion-side main oil passage 44 of the piston 27, and the first sub-disk valve 51 and the first to third The main disk valves 54 to 56 are bent and opened, and flow from a gap formed between the piston 27 and the first sub disk valve 51 to the piston side oil chamber 28A. Thereby, a damping force due to the bending resistance of the first sub disk valve 51 and the first to third main disk valves 54 to 56 is obtained. At this time, the second sub-disk valve 52 closes the orifice 51A of the first sub-disk valve 51, and the oil passing through the expansion-side bypass oil passages 71, 72 of the expansion-side damping force variable valve device 80 is supplied to the piston 27 described above.
From the gap between the first sub-disc valve 51 and the first sub-disc valve 51 to the piston-side oil chamber 28A.

(At the time of compression) This is the same as at the time of decompression described above.

That is, when the operating speed of the piston 27 is low, the oil pressure in the piston-side oil chamber 28A passes through the pressure-side bypass oil passages 73 and 74 adjusted by the needle valve 93 of the pressure-side damping force variable valve device 90, and the pressure-side damping occurs. Force generating valve device 6
0 acts on the orifice 61A of the first sub-disc valve 61 to deflect the second sub-disc valve 62 and push it open. It flows to the rod side oil chamber 28B via the slit 68A. Thereby, the damping force due to the throttle resistance of the needle valve 93 of the compression side damping force variable valve device 90 and the second sub disc valve 62
, A damping force due to the bending resistance is obtained.

When the operating speed of the piston 27 is medium or high,
The oil pressure in the piston-side oil chamber 28A acts on the first sub-disk valve 61 of the compression-side damping-force generating valve device 60 from the compression-side main oil passage 45 of the piston 27, and the first sub-disk valve 61 and the first to third main disks. Valve 64-66
Is flexed to open, and flows from the gap formed between the piston 27 and the first sub-disc valve 61 to the rod-side oil chamber 28B. Thereby, the damping force due to the bending resistance of the first sub-disk valve 61 and the first to third main disk valves 54 to 56 is obtained. At this time, the second sub-disc valve 62 closes the orifice 61A of the first sub-disc valve 61, and the oil passing through the compression-side bypass oil passages 73 and 74 of the compression-side damping force variable valve device 90 is discharged from the piston 2
Flow from the gap between the first sub-disk valve 61 and the first sub-disk valve 61 to the rod-side oil chamber 28B.

In the modification shown in FIG. 6, the slit 58A is formed in the ring 58 of the extension side damping force generating valve device 50 (the same applies to the ring 68 of the compression side damping force generating valve device 60).
This is an example in which only the flange portion 58B is not provided. In this case, the inner diameter of the ring 58 is minutely arranged on the outer periphery of the second sub-disc valve 52 so that the center of the ring 58 incorporated in the extension side damping force generating valve device 50 is performed by the outer periphery of the second sub-disc valve 52. Assemble through the gap.

Therefore, according to the present embodiment, the following operations are provided. At the beginning of the operation of the piston 27, the oil passage 4
The hydraulic pressure in the pumps 4 and 45 is also controlled by the damping force variable valve device 70 (8
0, 90), the oil pressure in the bypass oil passages 71, 72, 73, 74 is also small, so that the oil passages 44, 45 of the piston 27 remain closed by the first sub-disc valves 51, 61 and the damping force is variable. Valve device 70 (80, 90)
1st communicating with the bypass oil passage 71,72,73,74 of
Orifices 51A, 6 of sub-disc valves 51, 61
1A is kept closed by the second sub-disc valve, so that a high damping force is obtained. And piston 2
When the operating speed of 7 reaches some low speed and reaches the low speed range,
The second sub-disc valves 52, 62 are bent to open the orifices 51A, 61A, and the damping force variable valve device 70 (8
0, 90), the hydraulic oil in the bypass oil passages 71, 72, 73, 74 passes through the orifices 51A, 61A and the ring 5
8, 68 flow to the oil chambers 28A, 28B of the cylinder 11 from the slits 58A, 68A, and the damping force variable valve device 70
The damping force set to (80, 90) and the damping force due to the bending of the second sub-disk valves 52, 62 are obtained. At this time, the second sub-disc valves 52 and 62 may have only a check valve function and do not generate a damping force.

When the operating speed of the piston 27 further increases and reaches the middle to high speed range, the first sub-disc valves 51, 61
And the main disc valves 54 to 56 and 64 to 66 are bent and opened with the rings 58 and 68 interposed therebetween, and the hydraulic oil in the oil passages 44 and 45 of the piston 27 flows between the piston 27 and the first sub disc valves 51 and 61. Flows into the oil chambers 28A, 28B of the cylinder 11 from the gap formed in the first sub disk valves 51, 61 and the main disk valves 54-5.
6, a damping force due to the bending of 64 to 66 is obtained. This damping force is applied to the main disc valves 54-56, 64-66.
Can be changed by laminating a plurality of sheets. At this time, the second sub-disc valves 52, 62 close the orifices 51A, 61A of the first sub-disc valves 51, 61, and the bypass oil passages 71, 72, 73, 74 of the damping force variable valve device 70 (80, 90). Hydraulic oil flows into the oil chambers 28A and 28B of the cylinder 11 from the gap formed between the piston 27 and the first disk valve.

The rings 58 and 68 are composed of the first sub disk valves 51 and 61 and the main disk valves 54 to 56 and 6 respectively.
Cylinders 11 and 69 formed between
Slits 58A, 6 communicating with the oil chambers 28A, 28B inside
Since 8A is provided on the rings 58 and 68, it is not necessary to provide a disk valve with a slit in addition to the rings 58 and 68, and the number of parts can be reduced.

The aforementioned variable damping force valve device 70 (8
0, 90), the damping force of the piston 27 generated in the low speed range can be varied.

The variable damping force valve device 70 (80, 9
The first and second sub-disc valves 51, 61 and 52 constituting the sub-valve mechanism for opening and closing the bypass oil passages 72, 74 in the piston round surface of the piston 27, and opening and closing the bypass oil passages 72, 74. , 62 are laminated on the main disk valves 54 to 56 and 64 to 66, so that there is no need to provide a sub-valve mechanism separate from the piston 27, and the number of parts can be reduced.

Since there is no need to provide a sub-valve mechanism separately from the piston 27, no space is required for disposing the sub-valve mechanism, and the damping force generating mechanism can be made compact.

The slits 58 provided in the rings 58, 68
A, the total flow passage area of 68A
The total flow passage area of the orifices 51A and 61A provided in the first and the 61 was made larger. Therefore, the first sub disc valve 5
1, 61 and main disc valves 54 to 56, 64 to 6
6, the gaps 59, 69 formed by the rings 58, 68 are always provided with the large opening slits 58A, 68A from the cylinder 11
The oil pressure in the gaps 59 and 69 does not rise, and the oil pressure in the gaps 59 and 69 does not open only the main disk valves 54 to 56 and 64 to 66. That is, the first sub-disc valve 5
1, 61 and main disc valves 54 to 56, 64 to 6
Numeral 6 stably fixes the rings 58 and 68 in the axial direction without any gap, and prevents the rings 58 and 68 from falling off and generating abnormal noise.

The collar portions 58B, 68 of the rings 58, 68
By contacting B with the outer circumferences of the main disk valves 54 to 56 and 64 to 66, the rings 58 and 68 can be centered, and the rings 58 and 68 are positioned and fixed without always moving in the radial direction. Falling off,
Generation of abnormal noise can be prevented.

It should be noted that the collars 58B, 6
If the ring 8B is not provided, another radial positioning means may be provided on the rings 58, 68, or the inner circumferences of the rings 58, 68 may be brought into contact with the outer circumference of the second disk valve so that the rings 58, 68 are provided.
8 can be centered (FIG. 6).

The flanges 58B, 68 of the rings 58, 68
B, the centering of the rings 58, 68 is performed by the outer circumference of the main disk valves 54 to 56, 64 to 66, and is not performed by the outer circumference of the second sub disk valves 52, 62. The radial size of 62 can be freely changed (thickness can also be changed), and the above-described bending force and opening timing of the second sub-disc valves 52 and 62 can be freely set to adjust the damping characteristics.

The flanges 58B, 68 of the rings 58, 68
If B is continuous over the entire circumference, the height of the slits 58A and 68A provided in the rings 58 and 68 can be made equal to the total thickness of the second sub-disc valve and the sub-valve seat,
Since the total flow area of the slits 58A and 68A can be made larger, it is possible to reliably fix the rings 58 and 68 in the axial direction as described above.

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 without departing from the scope of the present invention. The present invention is also included in the present invention. The present invention includes any design change or the like within a range not departing from the gist of the present invention. For example, in the present invention, the damping force generating valve device may include at least one of the extension side and the compression side.

In the present invention, the damping force variable valve device may have at least one of the extension side and the compression side. Further, the damping force variable valve device is not limited to a device using a needle valve, but may be a device using a rotary valve (a device having a plurality of orifices having different hole diameters communicating with a bypass oil passage).

[0068]

As described above, according to the present invention, in a hydraulic shock absorber capable of increasing the damping force in the initial stage of the operation of the piston, the number of parts can be reduced and the damping force generated in the low-speed range of the piston can be made variable. be able to.

According to the object of the present invention, it is possible to simply and fixedly arrange a ring for allowing the second sub-disc valve to bend so as to open and close the orifice of the first sub-disc valve in the early stage of operation of the piston. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a hydraulic shock absorber.

FIG. 2 is an enlarged sectional view showing the damping force adjuster device of FIG.

FIG. 3 is an enlarged sectional view showing the valve device of FIG. 1;

FIG. 4 is a schematic diagram showing a damping force generating valve device taken out therefrom.

FIG. 5 is a plan view showing a ring.

FIG. 6 is a schematic view showing a modification of the damping force generating valve device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hydraulic shock absorber 11 Cylinder 12 Piston rod 27 Piston 28A Piston side oil chamber 28B Rod side oil chamber 40, 50, 60 Damping force generating valve device 44, 45 Oil path 51, 61 First sub disk valve 51A, 61A Orifice 52, 62 Second sub-disc valve 53, 63 Sub-valve seat 54-56, 64-66 Main disc valve 57, 67 Main valve seat 58, 68 Ring 58A, 68A Slit 58B, 68B Collar 59, 69 Spacing 70, 80, 90 Variable damping force valve device 71, 72, 73, 74 Bypass oil passage

Claims (3)

[Claims] 1. A piston rod is inserted into a cylinder, and a piston-side oil chamber and a rod-side oil chamber are defined in the cylinder by a piston provided on the piston rod. And a damping force generating valve device for controlling the flow of hydraulic oil in the main oil passage to generate a damping force. The main oil passage provided on the piston rod on the piston By controlling the flow area of the hydraulic oil in the bypass oil passage by adjusting the opening area of the bypass oil passage and the bypass oil passage that enables communication between the piston-side oil chamber and the rod-side oil chamber by bypassing the oil passage. A damping force variable valve device for generating a damping force by means of a damping force generating valve device, wherein the damping force generating valve device comprises a main oil passage and a damping force variable on a piston round surface of the piston. The bypass oil passage of the variable damping valve device, which is provided so as to open and close a main oil passage that opens on a piston round surface of the piston and opens a bypass oil passage of the lube device together with the main oil passage that opens on a piston round surface of the piston. A first sub-disc valve having an orifice communicating with the first sub-disc valve, a second sub-disc valve contacting the first sub-disc valve and closing the orifice; a sub-valve seat contacting the second sub-disc valve; A main disc valve in contact with the valve seat, a main valve seat in contact with the main disc valve, and a gap interposed between the first sub disc valve and the main disc valve to allow the second sub disc valve to flex. And a slit communicating the interval with an oil chamber in the cylinder. Hydraulic shock absorber comprising and a ring made. 2. The hydraulic shock absorber according to claim 1, wherein a total flow area of the slit provided in the ring is larger than a total flow area of the orifice provided in the first sub-disc valve. 3. The hydraulic shock absorber according to claim 1, wherein the ring includes a flange portion that contacts an outer periphery of the main disk valve.