JP2001263403A - Hydraulic buffer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of part item a hydraulic buffer which can increase the damping force in the initial operation of a piston. SOLUTION: In the hydraulic buffer 10 having damping force generating valves 40 (50, 60), the damping force generating 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]

However, the prior art has the following problems. It is necessary to provide a third disc valve having a slit communicating with the cylinder chamber, that is, a third disc valve having a slit communicating with the cylinder chamber, in addition to the ring, in addition to the ring. , The number of parts increases.

The above-mentioned ring is sandwiched between the first disk valve and the third disk valve, and has a small radial gap between the ring and 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.

An object of the present invention is to reduce the number of parts in a hydraulic shock absorber capable of increasing a damping force in an early stage of operation of a piston.

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.

[0009]

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. An oil passage that allows the piston to communicate with the piston-side oil chamber and the rod-side oil chamber, and a damping force generation valve device that controls the flow of hydraulic oil in the oil passage to generate a damping force. In the hydraulic shock absorber, the damping force generating valve device is provided so as to open and close an oil passage of the piston, and includes a first sub disk valve including an orifice communicating with the oil passage, and a first sub disk. A second sub-disc valve that contacts the valve and closes the orifice, a sub-valve seat that contacts the second sub-disc valve, and a main disc that contacts the sub-valve seat And Lube, a main valve seat in contact with the main disk valve, interposed between the first sub disk valve and the main disk valve, so as to form a gap to permit deflection of the second sub disk valve,
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.

[0012]

According to the first aspect of the present invention, the following operations are provided. At the beginning of the operation of the piston, the oil pressure in the oil passage of the piston is small, so that the oil passage of the piston remains closed by the first sub-disk valve, and the orifice of the first sub-disk valve is closed by the second sub-disk valve. Since it remains closed, a high damping force is obtained. When the operating speed of the piston increases to a certain extent and reaches a low-speed range, the second sub-disc valve bends to open the orifice, and the operating oil in the oil passage of the piston passes through the orifice from the slit of the ring to the oil chamber of the cylinder. And the damping force due to the bending of the second sub-disk valve is obtained.

When the operating speed of the piston further increases and reaches the 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 oil passage of the piston is disengaged with the piston and the second. The fluid flows from the gap formed between the one sub-disk valve to the oil chamber of the cylinder, and a 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.

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.

According to the second aspect of the present invention, the following operations are provided. 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 present 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. Since the area can be made larger, it is possible to reliably fix the ring in the axial direction as described above.

[0020]

FIG. 1 is a sectional view showing a hydraulic shock absorber.
2 is an enlarged sectional view showing the valve device of FIG. 1, FIG. 3 is a schematic view showing the damping force generating valve device taken out, FIG. 4 is a plan view showing a ring, and FIG. 5 is a modification 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 an impact from the road surface, and the cylinder 11 incorporates a damping force generating valve device 40 described later to suppress 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 is provided with 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 has a damping force generating valve device 40 (an extension side damping force generating valve device 50 and a compression side damping force generating valve device 60), and the damping force generated by these damping force generating valve devices 40. Thereby, 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 is suppressed.

(Damping Force Generating Valve Device 40) (FIGS. 1 to 4) As shown in FIG. 2, the damping force generating valve device 40 is a piston bolt screwed to the end of the piston rod 12 inserted into the cylinder 11. 26 is a pressure-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
And a compression-side oil passage 45 that communicates with the oil pressure.

The expansion-side damping-force generating valve device 50 is disposed on the side of the piston 27 facing the piston-side oil chamber 28A, and generates an expansion-side damping force during extension by closing the expansion-side oil passage 44. The compression side damping force generating valve device 60 is arranged on the side of the piston 27 facing the rod side oil chamber 28B, and generates a compression side damping force during compression by closing the compression side oil passage 45.

As shown in FIG. 3, the extension-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, 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 oil passage 44 of the piston 27, and includes an orifice 51A communicating with the extension-side oil passage 44. The second sub disc valve 52 contacts the first sub disc valve 51 and closes the orifice 51A. The sub valve seat 53 is
It contacts the sub-disc valve 52. The first main disc valve 54 contacts the sub-valve seat 53, and the second
The third main disk valves 55 and 56 are stacked on top of 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. 3 and 4, 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. 2, 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.

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

(Extension) When the operating speed of the piston 27 is low, the hydraulic pressure in the rod-side oil chamber 28B passes through the extension-side oil passage 44 of the piston 27 and the first sub-disc valve of the extension-side damping-force generating valve device 50. Acting on the orifice 51A of 51, the second sub-disc valve 52 is bent and pushed open, and the slit 58 of the ring 58 is determined from the distance 59 between the first sub-disc valve 51 and the first main disc valve 54.
The oil flows to the piston side oil chamber 28A via A. This allows
The damping force due to the bending resistance of the second sub-disk valve 52 is obtained.

When the operating speed of the piston 27 is medium to high,
The hydraulic pressure in the rod-side oil chamber 28 </ b> B is
4 acts on the first sub-disc valve 51 of the extension-side damping-force generating valve device 50, and flexes and opens the first sub-disc valve 51 and the first to third main disc valves 54 to 56, and the piston 27 and the first It flows from the gap formed between the one sub-disc valve 51 to the piston side oil chamber 28A. Thereby, the first sub disk valve 51 and the first to first
The damping force due to the bending resistance of the third main disk valves 54 to 56 is obtained. At this time, the second sub disc valve 52 is connected to the orifice 51 of the first sub disc valve 51.
Close A.

(At the time of compression) This is the same as at the time of expansion described above. That is, when the operating speed of the piston 27 is low, the oil pressure in the piston-side oil chamber 28A acts on the orifice 61A of the first sub-disc valve 61 of the compression-side damping force generation valve device 60 through the compression-side oil passage 45 of the piston 27. Then, the second sub-disc valve 62 is bent and pushed open, and flows from the space 69 between the first sub-disc valve 61 and the first main disc valve 64 to the rod-side oil chamber 28B via the slit 68A of the ring 68. Thereby, a damping force due to the bending resistance of the second sub-disk valve 62 is obtained.

When the operating speed of the piston 27 is medium to 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 pressure-side oil passage 45 of the piston 27, and the first sub-disk valve 61
And the first to third main disc valves 64 to 66 are bent and opened, and the piston 27 and the first sub disc valve 61 are opened.
Flows into the rod-side oil chamber 28B from the gap formed between them. Thereby, the first sub disk valve 61 and the first to first
The damping force due to the bending resistance of the third main disk valves 54 to 56 is obtained. At this time, the second sub disc valve 62 is connected to the orifice 6 of the first sub disc valve 61.
Close 1A.

In the modification shown in FIG. 5, 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
4 and 45, the hydraulic pressure in the piston 27
4 and 45 remain closed by the first sub-disc valves 51 and 61 and
Since the orifices 51A and 61A of the first and the first 61 remain closed by the second sub-disc valves 52 and 62,
High damping force can be obtained. When the operating speed of the piston 27 increases to some extent and reaches a low speed range, the second sub-disc valves 52 and 62 bend and the orifices 51A and 6A.
1A, the hydraulic oil in the oil passages 44, 45 of the piston 27 passes through the orifices 51A, 61A and the rings 58, 68
From the slits 58A, 68A of the oil chamber 28 of the cylinder 11
A, 28B, and the second sub-disc valves 52, 62
, A damping force due to the bending is obtained.

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.

The rings 58 and 68 are connected to 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 additionally provide disk valves with slits 58A and 68A in addition to the rings 58 and 68, and the number of parts can be reduced.

The slit 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.

The collars 58B, 6 are attached to the rings 58, 68, respectively.
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. 5).

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.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and the design may be changed without departing from the scope of the present invention. The present invention is also included in 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.

[0049]

As described above, according to the present invention, the number of parts can be reduced in the hydraulic shock absorber which can increase the damping force in the early stage of the operation of the piston.

Another object of the present invention is to easily 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.

[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 valve device of FIG. 1;

FIG. 3 is a schematic diagram showing a damping force generating valve device taken out therefrom.

FIG. 4 is a plan view showing a ring.

FIG. 5 is a schematic view showing a modified example 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 generation 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

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 that controls the flow of hydraulic oil in the oil passage to generate a damping force, wherein the damping force generating valve device includes: A first sub-disc valve provided to open and close the oil passage of the piston and having an orifice communicating with the oil passage; and a second sub-disc contacting the first sub-disc valve to close the orifice. A valve, a sub-valve seat that contacts the second sub-disc valve, a main disc valve that contacts the sub-valve seat, and a contact with the main disc valve A main valve seat, which is interposed between the first sub-disc valve and the main disc valve, forms a gap allowing the deflection of the second sub-disc valve, and communicates the gap with an oil chamber in the cylinder. A hydraulic shock absorber comprising: a ring comprising: 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.