JP3058526B2 - Damping force adjustable hydraulic shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force-adjustable hydraulic shock absorber which is used, for example, for damping the vibration of a vehicle and which can adjust the damping force according to the road surface condition.

[0002]

2. Description of the Related Art FIGS. 7 to 10 show a conventional damping force adjusting type hydraulic shock absorber.

In the drawing, reference numeral 1 denotes a cylinder constituting a main body of a hydraulic shock absorber, and 2 denotes a piston rod having one end inserted into the cylinder 1 and the other end projecting out of the cylinder 1. An insertion hole 3 is formed in the axial direction, and an oil passage 4 communicating with the insertion hole 3 is formed in the radial direction.

A piston 5 is provided at one end of the piston rod 2. The piston 5 defines two oil chambers A and B in the cylinder 1, and the piston 5 is inclined between the oil chambers A and B. Are communicated through oil passages 6 and 7 formed in the holes. Reference numerals 8 and 9 denote an extension-side damping force generation mechanism and a reduction-side damping force generation mechanism provided on both end surfaces of the piston 5.

[0005] Reference numeral 10 denotes a cylindrical member having a lid 10A screwed to one end of the piston rod 2, and the cylindrical member 10 has an open end 10B at one end and a lid 10A at the other end. And serves also as a lock nut for fixing the piston 5 to one end of the piston rod 2.

Reference numeral 11 denotes an orifice tube fitted and fixed in the cylindrical member 10. The orifice tube 11 is formed in a closed cylindrical shape with an outer diameter corresponding to the inner diameter of the cylindrical member 10. By caulking the opening end 10B side, it is positioned in the tubular member 10. Further, a rod insertion hole 11B for inserting an adjustment rod 14, which will be described later, is formed in the cover 11A of the orifice cylinder 11 in the axial direction.
The rod insertion hole 11B has a larger diameter than the adjustment rod 14.

As shown in FIG. 8, six oil passages 12A, 12B, 12C, 12D, 12E, and 60 are provided on the outer peripheral wall of the orifice cylinder 11 at intervals of, for example, 60 degrees in the circumferential direction.
12F (generally referred to as an oil passage 12) is formed in the axial direction, and large-diameter soft orifices 13A, 13A are provided at the positions of the oil passages 12A, 12D.
In the position of E, small-diameter medium orifices 13B, 13
B is drilled in the radial direction (hereinafter, orifice 1
The orifice 13 determines the damping force characteristic at the time of the reduction stroke as described later. No orifices are formed at positions corresponding to the oil passages 12C and 12F, and the positions are hard positions HH. Also,
The orifices 13 are formed on the outer peripheral wall of the orifice cylinder 11 at two locations spaced apart in the axial direction.

Reference numeral 14 denotes an adjusting rod inserted into the insertion hole 3 of the piston rod 2 with a relatively large gap. The distal end of the adjusting rod 14 extends into the orifice cylinder 11 through the rod insertion hole 11B. Base end is piston rod 2
Is connected to a rotary actuator (not shown) for damping force adjustment and the like on the protruding end side. Then, the adjusting rod 14 is rotated by the rotary actuator,
A later-described shutter 15 is rotated.

Reference numeral 15 denotes a damping force adjusting shutter rotatably provided in the orifice cylinder 11. The shutter 15 is formed in a closed cylindrical shape with an outer diameter corresponding to the inner diameter of the orifice cylinder 11. The adjustment rod 14 is provided on the portion 15A.
Are fixed by caulking means or the like. As shown in FIG. 8, a pair of notches 16 and 16 are formed on the peripheral wall of the shutter 15 at positions opposing each other in the radial direction.
A and 13B are selectively opened and closed. Reference numeral 17 denotes an annular oil passage formed between the insertion hole 3 of the piston rod 2 and the adjustment rod 14, and the oil passage 17 constantly communicates with the oil passages 4 and 12, and an oil passage 20 described later. , 22, etc., constitute an oil passage for communicating between the oil chambers A, B.

Reference numeral 18 denotes a check valve mounted on the outer peripheral side of the orifice cylinder 11. As shown in FIGS. 9 and 10, the check valve 18 has a disc-shaped bottom plate 18A and a radial direction from the bottom plate 18A. Six long-plate check valves 18B, 18B,... Formed by bending a long plate extending at 60-degree intervals at right angles.
And a space 18 between the check valves 18B.
C, 18C,... Each of the opposed check valve bodies 18B is provided with a large-diameter soft orifice 19A, 19A corresponding to the orifice 13A, 13A. A small diameter orifice 19B, 19B for the medium is formed in the stop element 18B in correspondence with the orifices 13B, 13B (hereinafter referred to as the orifice 19 as a whole).

The orifices 19A and 19B determine the damping force characteristic during the extension stroke of the piston rod 2 as described later, and the opening area thereof is
A, 13B. Also, each check valve element 18 adjacent to and opposed to the other side of each of the orifices 19A.
B has no orifice drilled and hard position HH
Is composed. On the other hand, the orifices 19 are formed at two locations in the axial direction of each check valve element 18B,
A is provided with a circular oil passage hole 20.

Reference numeral 21 denotes a bottom cover provided on the side of the opening end 10B of the cylindrical member 10. The bottom cover 21 is provided between the bottom cover 18A of the check valve 18 and the orifice tube 11 provided in the cylindrical member 10.
The orifice cylinder 11 and the check valve 18 are positioned in the cylindrical member 10 in the axial direction by caulking the opening end 10B of the cylindrical member 10.

Accordingly, the orifices 13A, 19
A is positioned so as to be coaxial in the radial direction as shown in FIG.
B and 19B are positioned so as to be coaxial in the radial direction to be a medium position MM, and a position where no orifice is formed is a hard position HH.

Reference numeral 22 denotes an oil passage hole formed in the bottom cover 21. The oil passage hole 22 is coaxial with the oil passage hole 20 of the check valve 18. Reference numeral 23 denotes a sliding plate formed of an annular flat plate disposed between the lid 11A of the orifice cylinder 11 and the lid 15A of the shutter 15.

The prior art is configured as described above, and its operation will now be described.

First, the adjusting rod 14 is rotated from outside the cylinder 1 by the rotary actuator to rotate the shutter 15, and the notch grooves 16 of the shutter 15 are set at predetermined positions, for example, a soft position S- shown in FIG. Set to S.

Therefore, when the piston rod 2 is in the extension stroke, the pressure in the oil chamber A becomes high, and the pressure oil in the oil chamber A is supplied to the oil passage 4, the annular oil passage 17, the oil passages 12A, 12D, the orifices 19A, The oil flows out from the oil passage holes 20 and 22 into the oil chamber B through the cutout grooves 16 and the cutout grooves 13A. At this time, the oil passage 12
Presses each check valve element 18B of the check valve 18 from the back surface toward the inside in the radial direction, and presses each check valve element 18B.
This pressure oil flows toward the inside of the shutter 15 through the orifices 19A and 13A in order to bring the pressure oil into close contact with the outer peripheral surface of the orifice cylinder 11. However, since the opening area of the orifice 19A is formed smaller than the opening area of the orifice 13A, a damping force corresponding to a predetermined software is generated by the resistance of the pressure oil flowing through the orifice 19A.
When the speed of the piston rod 2 increases, the damping force generation mechanism 8 opens to generate a predetermined damping force.

On the other hand, when the piston rod 2 is in the reduction stroke, the pressure in the oil chamber B becomes high, and conversely, the pressure oil in the oil chamber B is conveyed to the oil passage holes 22, 20, the notch groove 16, and the orifice 13A. , 19A, the oil passages 12A and 12D, the annular oil passage 17 and the oil passage 4 to the oil chamber A. At this time, the pressure oil that has reached the orifice 13A presses each check valve element 18B of the check valve 18 toward the outside in the radial direction, and separates from the orifice cylinder 11. For this reason, the pressure oil from the orifice 13A flows out of the space 18C between the check valves 18B into the oil passages 12A and 12D without resistance. As a result, a damping force corresponding to predetermined software is generated by the resistance of the pressure oil flowing through the orifice 13A. When the speed of the piston rod 2 increases, the damping force generating mechanism 9 opens,
A predetermined damping force is generated.

Next, the shutter 1 is moved by the adjusting rod 14.
Even when 5 is set from the soft position SS to the medium position MM, a damping force corresponding to a predetermined medium can be generated as described above.

Further, when the shutter 15 is set at the hard position HH by the adjusting rod 14, the orifices 13 and 19 are not formed at the hard position HH, and the shutter 15 and the like are provided. Thus, pressure oil does not flow between the oil chambers A and B, so that damping force characteristics depending on the damping force generating mechanisms 8 and 9 can be obtained.

[0021]

In the prior art described above, the shutter 15 is formed in a closed cylindrical shape with an outer diameter corresponding to the inner diameter of the orifice cylinder 11, and a pressure is applied between the orifice cylinder 11 and the shutter 15. Since the oil is prevented from leaking, the rod insertion hole 11B drilled in the lid 11A of the orifice cylinder 11 is
If the center of the orifice cylinder 11 and the shutter 15 is slightly misaligned unless it is formed larger than the diameter of the orifice cylinder 11, the orifice cylinder 11 is fixed to the lid 15A of the shutter 15 by caulking or the like. The adjustment rod 14 interferes with the rod insertion hole 11B of the cylinder 11, or the outer peripheral surface of the shutter 15 contacts and interferes with the inner peripheral surface of the orifice cylinder 11, so that the shutter 15 can be smoothly rotated within the orifice cylinder 11. Disappears.

However, if the diameter of the rod insertion hole 11B of the orifice cylinder 11 is larger than that of the adjustment rod 14, a relatively large gap is interposed between the rod insertion hole 11B and the adjustment rod 14, so that the orifice cylinder 11 and the shutter Pressure oil leaks between the inside of the oil passage 15 and the oil passage 17 through the rod insertion hole 11B, and the damping force characteristic changes.

For this reason, in the prior art, the orifice cylinder 11
The sliding plate 23 made of an annular flat plate is disposed between the lid 11A of the shutter 15 and the lid 15A of the shutter 15, and the sliding plate 23 seals the sliding plate 23 between the two. It prevents leakage of pressurized oil. However, in the related art, for example, when the pressure oil in the oil chamber B becomes high pressure and acts on the cover 15A of the shutter 15 in a state where the shutter 15 is set to the hard position HH, the cover 15 15A is strongly pressed against the lid 11A of the orifice tube 11, and the shutter 15 cannot be smoothly rotated in the orifice tube 11, which makes it difficult to adjust the damping force.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention can smoothly rotate a shutter in an orifice cylinder, and can smoothly adjust a damping force. It is an object of the present invention to provide a damping force-adjustable hydraulic shock absorber that can easily prevent pressure oil from leaking into and out of an orifice cylinder from the periphery thereof and stabilize damping force characteristics.

[0025]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cylinder and an axially extending through hole, one end of which is inserted into the cylinder and the other end of which protrudes out of the cylinder. A piston rod, a piston fixed to one end of the piston rod, and defining two oil chambers in the cylinder, and a piston rod formed between the two oil chambers defined by the piston. An oil passage that communicates through the insertion hole, an orifice tube that is provided in the middle of the oil passage, and has an orifice formed in the radial direction, and an outer diameter corresponding to the inner diameter of the orifice tube. A shutter for adjusting damping force, which is formed in a tubular shape and is rotatably provided in the orifice tube so as to open and close the orifice, is provided in an insertion hole of the piston rod so as to rotate the shutter. Threaded, one end side is applied to the damping force adjustable hydraulic shock absorber through the lid of the orifice tube comprising a adjusting rod secured to the shutter.

The first aspect of the present invention has the following structure.
The feature is that the lid of the orifice cylinder and the lid of the shutter
In between, it is always in communication with the inside of the shutter, and the lid of the shutter
A back pressure chamber for applying a back pressure to the orifice tube, and a rod insertion hole through which one end of the adjustment rod is inserted and having a diameter larger than that of the adjustment rod is formed in the lid of the orifice cylinder; between the insertion hole and the adjusting rod has a through hole of diameter corresponding to the contact pre Symbol adjusting rod to the lid of the orifice tube and the sealing plate portion which is formed in the center side, of the sealing plate portion consisting of the sealing plate portion is integrally formed on the outer peripheral side and a plurality of legs for pressing with a spring property to the end face of the lid Shirusupuri
It is configured to be closed by ringing .

[0027]

According to the above construction, a back pressure corresponding to the pressure in the shutter can be constantly applied to the lid of the shutter.
For example, even when a high pressure in the shutter acts on the lid while the shutter is set to the hard position, it is possible to prevent the lid of the shutter from being strongly pressed against the lid of the orifice cylinder.

In addition, by using a seal spring, the gap between the rod insertion hole and the adjustment rod can be easily sealed, and it is possible to reliably prevent the damping force characteristic from being changed due to leakage of pressure oil through the rod insertion hole. .

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the conventional technology shown in FIG. 7 described above are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 1 to 3 show a first embodiment of the present invention.

In the figure, reference numeral 31 denotes a damping force adjusting shutter which is rotatably provided in the orifice tube 11. The shutter 31 is formed in a closed cylindrical shape almost in the same manner as the shutter 15 described in the prior art. , A pair of notch grooves 16,
16 is provided, but the lid 3 of the shutter 31 is provided.
A plurality of oil holes 31B, 31B,... Are bored in 1A in the axial direction so as to be radially separated from the fixing portion of the adjustment rod 14. Each of the oil holes 31B allows the inside of the shutter 31 and the oil chamber B to always communicate with a back pressure chamber 33 described later, and applies a back pressure corresponding to the pressure in the shutter 31 to the lid 31A of the shutter 31.

Reference numeral 32 denotes a sliding plate interposed between the lid 11A of the orifice cylinder 11 and the lid 31A of the shutter 31, and the sliding plate 32 is formed by an annular flat plate having a predetermined thickness. The outer peripheral side is positioned in the radial direction by the inner peripheral surface of the orifice cylinder 11. A large-diameter hole is formed on the inner peripheral side of the sliding plate 32, and a back pressure chamber 33 communicating between the inside of the shutter 31 and each oil hole 31B is formed between the lids 11A and 31A. The back pressure chamber 33 applies a back pressure corresponding to the pressure in the shutter 31 to the lid 31A of the shutter 31 to perform a floating seal with an oil film between the lids 11A and 31A. .

Further, reference numeral 34 denotes a lid 10A of the cylindrical member 10.
And a seal spring disposed between the cover member 11A of the orifice cylinder 11 and the seal spring 34. The seal spring 34 is formed as shown in FIGS. 2 and 3 by press-forming a thin metal plate having spring properties. A flat pentagonal seal plate portion 34A and three legs extending obliquely downward from the outer peripheral edge of the seal plate portion 34A with a predetermined inclination and spaced apart at an interval of about 120 degrees in the circumferential direction. Part 34
B, 34B,...

Here, the tip side of each leg portion 34B becomes a semicircular step portion 34C bent outward so as to be parallel to the seal plate portion 34A.
C is in contact with the lid 10A of the tubular member 10 shown in FIG. A through hole 34D having a hole diameter corresponding to the adjustment rod 14 is formed in the center of the seal plate portion 34A of the seal spring 34 in the axial direction.
D is fitted to the outer peripheral surface of the adjustment rod 14 with substantially no gap. The seal spring 34 is shown in FIG.
And the orifice tube 1 as shown in FIG.
When disposed between the first lid 11A and each of the legs 34B,
Is elastically deformed so as to expand outward in the radial direction, thereby pressing the surface of the seal plate portion 34A against the end surface of the lid portion 11A of the orifice cylinder 11 with a spring property, and the rod insertion hole 11B and the adjustment rod around the through hole 34D. 14 is closed.

The hydraulic shock absorber with damping force adjustment according to the present embodiment has the above-described configuration, and its basic operation is not significantly different from that of the prior art.

However, in the present embodiment, each oil hole 31B is formed in the lid 31A of the shutter 31, and the sliding plate 32 is provided between the lid 11A of the orifice cylinder 11 and the lid 31A of the shutter 31. It is located on the inner peripheral side, inside the shutter 31 and each oil hole 31
B, a back pressure chamber 33 that is always in communication with the orifice tube 11 is provided. The gap between the rod insertion hole 11B of the orifice tube 11 and the adjustment rod 14 is formed by the lid 10A of the cylindrical member 10 and the orifice tube 1
Seal spring 34 disposed between the first cover 11A and the first lid 11A.
Therefore, the following operation and effect can be obtained.

That is, even when the shutter 31 is rotated to the hard position HH and the high pressure in the oil chamber B acts on the lid 31A of the shutter 31 with the orifices 13 and 19 closed, the shutter 31 is closed. The inside of the back pressure chamber 33 and each oil hole 31
Since the communication is made through B, the same pressure is always applied to both side surfaces of the lid 31A, and the lid 31A of the shutter 31 is effectively prevented from being pressed against the lid 11A of the orifice cylinder 11. it can. The pressure oil in the back pressure chamber 33 allows a floating seal between the lids 11A and 31A via the sliding plate 32, and the shutter 31
Can be smoothly rotated in the orifice cylinder 11.

Each leg 34 of the seal spring 34
B is elastically deformed between the lid 10A of the tubular member 10 and the lid 11A of the orifice cylinder 11, and presses the surface of the seal plate 34A against the end face of the lid 11A with a spring property.
Since a through hole 34D having a hole diameter corresponding to the outer diameter of the adjustment rod 14 is formed in the center of the seal plate portion 34A, a portion between the rod insertion hole 11B and the adjustment rod 14 is formed around the through hole 34D. Can be closed, and leakage of pressure oil between the oil passage 17 side and the back pressure chamber 33 via the rod insertion hole 11B can be reliably prevented.

Therefore, according to the present embodiment, the shutter 31
Can be smoothly rotated in the orifice tube 11, the damping force can be adjusted smoothly over a long period of time, and a seal spring 34 connects between the rod insertion hole 11B of the orifice tube 11 and the adjustment rod 14. It is possible to reliably seal, and it is possible to effectively prevent the damping force characteristic from being changed due to the leakage of the pressure oil through the rod insertion hole 11B.

Further, the seal spring 34 can be formed in a simple shape from a thin metal plate having spring properties, and even when the through hole 34D of the seal plate portion 34A comes into contact with the adjusting rod 14, the sliding resistance against the adjusting rod 14 is reduced. , And various effects such as smooth operation of the rotation of the adjustment rod 14 can be achieved.

FIGS. 4 to 6 show a second embodiment of the present invention. The feature of this embodiment is that an oil passage for communicating between two oil chambers defined in a cylinder by a piston is provided. A damping force valve is provided along with a damping force adjusting shutter on the way. In this embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted.

In the drawing, reference numeral 41 denotes a cylindrical member which also serves as a lock nut for fixing the piston 5 to one end of the piston rod 2, and the cylindrical member 41 is the cylindrical member 10 described in the prior art.
Although it has a lid 41A and an open end 41B in substantially the same manner as in the above, and is formed in a covered cylindrical shape, the tubular member 41 is formed relatively long. One end of the cylindrical member 41 has an enlarged diameter portion 41C having a diameter larger than that of the orifice tube 43 described later.
, And relatively large diameter oil holes 42, 42,... Are formed in the enlarged diameter portion 41C in the radial direction.

Reference numeral 43 denotes an orifice tube fitted and fixed in the cylindrical member 41. The orifice tube 43 is formed in a closed cylindrical shape almost in the same manner as the orifice tube 11 described in the prior art, and has an outer peripheral wall. Six oil passages 44, 44,... Are formed to extend to the position of the lid 43A at intervals of 60 degrees in the circumferential direction. The orifice tube 43 has a lid 43.
Rod insertion hole 4 larger in diameter than adjustment rod 14 in the center of A
3B is bored in the axial direction, and the rod insertion hole 43B prevents the adjustment rod 14 from interfering with the lid 43A even when the orifice cylinder 43 and a shutter 47 described later are misaligned. .

Reference numerals 45, 45,... Denote first orifices formed in the radial direction of the orifice tube 43. Each orifice 45 is formed two by two in the axial direction. The oil passages 44 are separated from each other in the direction. Reference numerals 46, 46,... Denote second orifices which are located on the opening end side of the orifice cylinder 43 and are bored in the radial direction. Each of the orifices 46 is spaced apart from the first orifice 45 in the axial direction. The orifice 45 is formed to have a smaller diameter than the orifice 45, and each of the orifices 45 and 46 constitutes a soft orifice and a medium orifice almost similarly to the orifice 13 described in the related art.

The orifice cylinder 43 has an outer peripheral wall which is located between the orifices 45 and 46 which are circumferentially separated from each other and does not form an orifice. HH. When the shutter 47 is set to the soft position SS or the medium position MM (see FIG. 8) so that the orifices 45 and 46 are opened by the cutout grooves 48 of the shutter 47 described later, In the extension stroke of 2, the pressure oil in the oil chamber A is changed to the oil passages 17, 44, the orifices 45,
The oil flows into the oil chamber B through the oil hole 46 and the oil hole 42, and the check valve 60, which will be described later, is opened during the reduction stroke of the piston rod 2. After flowing into the shutter 47, the orifice 45 and the oil passage 4
It flows toward the inside of the oil chamber A via 4 and 17.

Reference numeral 47 denotes a damping force adjusting shutter rotatably provided in the orifice cylinder 43.
7 shutter 31 foot URN Similarly as described in the first embodiment, the lid 47A a plurality of oil holes 47B, 47B, ... is bored with a pair of notched grooves 48 in the peripheral wall of the shutter 47, 4
8 is formed, the shutter 47 is formed to be relatively long, and each orifice 4
5, 46 are opened and closed. The shutter 47 has a cover 47A fixed to the distal end side of the adjustment rod 14, and is rotated through the adjustment rod 14, so that the soft position SS, the medium position MM, and the hard position HH are set. (See FIG. 8).

Reference numeral 49 denotes a sliding plate disposed between the lid 43A of the orifice cylinder 43 and the lid 47A of the shutter 47. The sliding plate 49 is the sliding plate described in the first embodiment. Board 3
2 is formed substantially in the same manner as in FIG.
A back pressure chamber 50 is provided which is always in communication with the inside of the shutter 47 through the shutter. Then, between the rod insertion hole 43B and the adjusting rod 14 of the orifice tube 43 is closed by the seal spring 34 in the first embodiment the same way.

Reference numeral 51 denotes a damping force valve attached to the opening end 41B side of the cylindrical member 41 via a spacer tube 52 or the like. The damping force valve 51 is an opening end 41 of the cylindrical member 41.
A valve body 53 held between the spacer cylinder 52 by caulking the B side and a disc valve 58 described later
And a check valve 60 and the like. As shown in FIG. 6, for example, four valve seats 54, 54,... Are formed in a fan shape on one end side of the valve body 53, and between the valve seats 54 are formed on the other end side. , For example, four valve seats 55, 55, 55
Are formed in a fan shape as shown in FIG.

In the axial direction of the valve body 53,
One end side is opened between the valve seats 54, and the other end side is opened in each valve seat 55.
, And one end side is opened in each valve seat 55, and the other end side is opened between the valve seats 55.
, And each of the oil passages 56 or 57 has an orifice 4 having a total passage area opened by the shutter 47.
6 are formed so as to be larger than the total flow path area.

A fixing pin 5 is attached to the valve body 53 so as to be detached from and seated on each valve seat 54 of the valve body 53.
9 shows a disc valve mounted via 9, the disc valve 58 opening earlier than the extension side damping force generating mechanism 8 of the piston 5 when the extension speed increases in the extension stroke of the piston rod 2, A predetermined damping force is generated.

Further, reference numeral 60 denotes a check valve mounted on the valve body 53 via a fixing pin 59 so as to be detached from and seated on each valve seat 55 of the valve body 53. The pressure oil in the oil chamber B is urged in the valve closing direction to reduce the pressure oil in the oil chamber B during the contraction stroke of the piston rod 2.
, The valve is opened against the spring 61. When the check valve 60 is opened, the total flow area of each oil passage 56 is larger than the total flow area of each orifice 46 opened by the shutter 47, so that the pressure oil in the oil chamber B is reversed. It flows into the oil chamber A via the stop valve 60, each notch groove 48 of the shutter 47, each orifice 45, each oil passage 44, the oil passage 17, and the like. At this time, when pressure oil flows through each orifice 45, A damping force corresponding to the opening area of the orifice 45 is generated.

Thus, in the present embodiment having the above-described structure, the same effects as those in the first embodiment can be obtained by the back pressure chamber 50 and the seal spring 34. Further, since the damping force valve 51 is provided on the opening end 41B side of the cylindrical member 41, the piston rod 2 is controlled by the disc valve 58 and the check valve 60 of the damping force valve 51.
Various effects can be obtained, such as the ability to generate damping forces having different characteristics in the extension stroke and the contraction stroke.

In the first embodiment, the check valve 18 is attached to the outer peripheral side of the orifice cylinder 11 to generate different damping forces between the extension stroke and the contraction stroke of the piston rod 2. The present invention is not limited to this. For example, the check valve 18 may be eliminated.

Further, in each of the above embodiments, the seal spring 34 is described as being constituted by the substantially pentagonal seal plate portion 34A and the three legs 34B, 34B,... The number of the legs 34B may be two or four or more.
It is formed in a square or circular shape, and the through hole 34
D may be provided.

[0055]

As described above in detail, according to the calling <br/> light according to claim 1, said shutter constantly communicating with the said shutter between the lid portion and the lid portion of the shutter of the orifice tube Back pressure on the lid
Forming a back pressure chamber which Ru allowed to act, the lid portion of the orifice tube
Has a rod insertion hole through which one end of the adjustment rod is inserted.
And close the gap between the rod insertion hole and the adjustment rod.
The sealing spring to be closed abuts the lid of the orifice cylinder
A through hole with a hole diameter corresponding to the adjustment rod
The integrated seal plate and the outer peripheral side of the seal plate
The sealing plate is formed on the end face of the lid with a spring property.
Since it is constituted by a plurality of pressing legs, the back pressure chamber
Thus, the shutter can be smoothly rotated within the orifice cylinder by the back pressure acting on the shutter lid, and the adjustment of the damping force can be performed smoothly over a long period of time.

Further, since the gap formed between the rod insertion hole of the orifice cylinder and the adjustment rod is closed by the seal spring, it is possible to prevent pressure oil from leaking through this gap. Various effects are exhibited, such as being able to stabilize the damping force characteristics and being able to form the seal spring itself with a simple shape at a low cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a damping force adjusting type hydraulic shock absorber according to a first embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a seal spring in FIG. 1;

FIG. 3 is a sectional view taken in the direction of arrows III-III in FIG. 2;

FIG. 4 is a longitudinal sectional view of a main part showing a damping force adjusting type hydraulic shock absorber according to a second embodiment.

5 is a sectional view taken along the line VV in FIG. 4 showing a valve seat and the like of the damping force valve.

FIG. 6 shows another valve seat and the like of the damping force valve.
It is arrow VI-VI direction sectional drawing in the middle.

FIG. 7 is a vertical sectional view of a main part showing a damping force adjusting type hydraulic shock absorber according to the related art.

FIG. 8 is a sectional view taken in the direction of arrows VIII-VIII in FIG.

FIG. 9 is a plan view of the check valve shown in FIG. 7;

FIG. 10 is a perspective view of the check valve shown in FIG. 7;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston rod 3 Insertion hole 4, 12, 17, 44 Oil passage (oil passage) 5 Piston 10, 41 Cylindrical member 10A, 11A, 31A, 41A, 43A, 47A Lid 11, 43 Orifice cylinder 13, 19 , 45, 46 Orifice 14 Adjusting rod 31, 47 Shutter 32, 49 Sliding plate 33, 50 Back pressure chamber 34 Seal spring 34A Seal plate 34B Leg 34D Through hole 51 Damping force valve A, B Oil chamber

Continuation of front page (56) References JP-A-1-135937 (JP, A) JP-A-3-51546 (JP, A) JP-A-3-272340 (JP, A) , U) Actually open 1988-48045 (JP, U) Actually open 1988-173534 (JP, U) Actually open 1988-182032 (JP, U) Actually open 2-109038 (JP, U) Actually open 4-39343 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16F 9/44 F16F 9/34 B60G 17/08

Claims (1)

(57) [Claims] A piston having an insertion hole formed in an axial direction, one end of which is inserted into the cylinder, and the other end of which is fixed to one end of the piston rod; A piston defining two oil chambers in the cylinder, an oil passage communicating between the two oil chambers defined by the piston through an insertion hole formed in the piston rod, and a middle of the oil passage. And an orifice tube having a closed cylindrical shape with an orifice formed in the radial direction, and a closed cylindrical shape having an outer diameter corresponding to the inner diameter of the orifice tube, and the orifice tube for opening and closing the orifice. A damping force adjusting shutter rotatably provided therein, and a shutter inserted through the insertion hole of the piston rod for rotating the shutter, with one end penetrating through the lid of the orifice cylinder. In the damping force adjustable hydraulic shock absorber comprising a anchored adjusting rod in Yatta, between the front Symbol lid of the orifice tube and the lid portion of the shutter,
A back pressure chamber is formed that constantly communicates with the inside of the shutter and applies a back pressure to the lid of the shutter. One end of the adjustment rod is provided in the lid of the orifice cylinder.
Is inserted and the rod becomes larger than the adjustment rod.
A hole is formed, and the orifice is provided between the rod insertion hole and the adjustment rod.
Penetration of the hole diameter that abuts on the lid of the cylinder and corresponds to the adjustment rod
A seal plate having a hole formed on the center side;
The seal plate portion is formed integrally on the outer peripheral side and is attached to the end surface of the lid portion.
Seals consisting of multiple legs that press with springiness
A damping force-adjustable hydraulic shock absorber characterized in that it is closed by pulling .