WO2024185398A1 - 減衰バルブおよび緩衝器 - Google Patents

減衰バルブおよび緩衝器 Download PDF

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Publication number
WO2024185398A1
WO2024185398A1 PCT/JP2024/004472 JP2024004472W WO2024185398A1 WO 2024185398 A1 WO2024185398 A1 WO 2024185398A1 JP 2024004472 W JP2024004472 W JP 2024004472W WO 2024185398 A1 WO2024185398 A1 WO 2024185398A1
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WO
WIPO (PCT)
Prior art keywords
valve
annular
seat
valve body
opposing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2024/004472
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
瞭汰 五味
義史 小林
裕紀 横山
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KYB Corp
Original Assignee
KYB Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by KYB Corp filed Critical KYB Corp
Priority to DE112024001165.9T priority Critical patent/DE112024001165T5/de
Priority to CN202480005674.2A priority patent/CN120752457A/zh
Publication of WO2024185398A1 publication Critical patent/WO2024185398A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/34—Special valve constructions; Shape or construction of throttling passages
    • F16F9/348—Throttling passages in the form of annular discs or other plate-like elements which may or may not have a spring action, operating in opposite directions or singly, e.g. annular discs positioned on top of the valve or piston body
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/50—Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics
    • F16F9/512—Means responsive to load action, i.e. static load on the damper or dynamic fluid pressure changes in the damper, e.g. due to changes in velocity

Definitions

  • the present invention relates to a damping valve and a shock absorber.
  • Shock absorbers are used, for example, by being interposed between the body and wheels of a vehicle in order to improve the ride comfort of the vehicle, suppressing vibrations of the body and wheels with the damping force they exert when expanding and contracting.
  • Such a shock absorber includes, for example, a cylinder, a rod that is movably inserted into the cylinder, a piston that is slidably inserted into the cylinder and divides the inside of the cylinder into an expansion side chamber and a compression side chamber, a free piston that is slidably inserted into the cylinder and divides an air chamber below the compression side chamber in the cylinder, a damping passage provided in the piston that connects the expansion side chamber and the compression side chamber, and a damping valve provided in the damping passage.
  • vehicle shock absorbers are required to exhibit damping force characteristics that increase the damping coefficient in the very low speed range where the extension/retraction speed is lower than the low speed range, and quickly increase the damping force when the extension/retraction stroke switches, and make the damping coefficient smaller in the low speed range than in the very low speed range, and furthermore, in the medium to high speed range above low speed, the damping coefficient is proportional to the extension/retraction speed but smaller than in the low speed range.
  • the damping valve is equipped with an annular leaf valve that is fixed on the inner circumference and allows deflection on the outer circumference, and an annular opposing seat that faces the outer circumference of the leaf valve but does not come into contact with it, and a valve seat member that has a port on the inner circumference of the opposing seat, providing resistance to the flow of hydraulic oil between the expansion side chamber and the compression side chamber.
  • the present invention aims to provide a damping valve and shock absorber that can prevent excessive damping force.
  • the damping valve of the present invention comprises an annular valve body in which one of the inner or outer circumference is a fixed end and the other of the inner or outer circumference is a free end that is allowed to flex relative to the fixed end, an annular opposing seat portion that is opposing at least a portion of the circumferential surface of the valve body on the free end side, and a valve seat member having a port provided radially on the fixed end side of the valve body relative to the opposing seat portion, and an orifice provided on the valve body that communicates between the valve seat member side and the opposite valve seat member side of the valve body with the valve body and the opposing seat portion directly facing each other.
  • FIG. 1 is a vertical sectional view of a shock absorber to which a damping valve according to an embodiment of the present invention is applied.
  • FIG. 2 is a partially enlarged cross-sectional view of a shock absorber to which a damping valve according to an embodiment of the present invention is applied.
  • Fig. 3(A) is a plan view of a first leaf valve constituting a valve body of a damping valve according to an embodiment of the present invention
  • Fig. 3(B) is a plan view of a second leaf valve constituting a valve body of a damping valve according to an embodiment of the present invention
  • Fig. 3(C) is a plan view of a third leaf valve constituting a valve body of a damping valve according to an embodiment of the present invention.
  • FIG. 3(A) is a plan view of a first leaf valve constituting a valve body of a damping valve according to an embodiment of the present invention
  • Fig. 3(B) is a plan view of a second leaf valve
  • FIG. 4 is a diagram showing the damping force characteristics of a shock absorber to which the damping valve according to one embodiment of the present invention is applied.
  • FIG. 5 is a partially enlarged cross-sectional view of a damping valve in a first modified example of an embodiment of the present invention.
  • a shock absorber D in one embodiment comprises a shock absorber body A that is expandable and contractible and has a cylinder 1 as an outer tube and a rod 2 movably inserted into the cylinder 1, and an expansion side sub-valve EV and a compression side sub-valve CV as damping valves provided between an expansion side chamber R1 and a compression side chamber R2 as two working chambers provided in the shock absorber body A.
  • This shock absorber D is used by being interposed between the body and wheels of a vehicle (not shown) to suppress vibrations of the body and wheels.
  • the shock absorber body A includes a cylindrical cylinder 1 with a bottom as an outer tube, a rod 2 that is movably inserted into the cylinder 1, and a piston 3 that is connected to the rod 2 and movably inserted into the cylinder 1, and that divides the inside of the cylinder 1 into an extension side chamber R1 and a compression side chamber R2 as working chambers.
  • a bracket (not shown) is provided at the base end of rod 2, which is the upper end in FIG. 1, and rod 2 is connected to one of the vehicle body and the wheel via said bracket (not shown).
  • a bracket (not shown) is also provided at bottom 1a of cylinder 1, and cylinder 1 is connected to the other of the vehicle body and the wheel via said bracket (not shown).
  • shock absorber D is interposed between the vehicle body and the wheels.
  • rod 2 moves in and out of cylinder 1
  • shock absorber D expands and contracts
  • piston 3 moves up and down (axially) within cylinder 1.
  • the shock absorber body A also has an annular rod guide 10 that closes the upper end of the cylinder 1 and through which the rod 2 is inserted so as to be able to slide freely around its inner circumference. This makes the inside of the cylinder 1 an enclosed space. A free piston 11 is inserted so as to be able to slide freely on the opposite side of the piston 3 from the rod 2 inside the cylinder 1.
  • a liquid chamber L is formed above the free piston 11 in the cylinder 1, and an air chamber G is formed below it. Furthermore, the liquid chamber L is divided by the piston 3 into an extension side chamber R1 on the rod 2 side and a compression side chamber R2 on the piston 3 side, and the extension side chamber R1 and the compression side chamber R2 are each filled with liquid.
  • the liquid filled in the shock absorber body A may be hydraulic oil, water, an aqueous solution, or other liquid.
  • the air chamber G is filled with air or a gas such as nitrogen gas in a compressed state.
  • a bladder or bellows may be used to separate the liquid chamber L and the air chamber G, and the configuration of the movable partition that separates the liquid chamber L and the air chamber G may be changed as appropriate.
  • the shock absorber D is a single-rod, single-cylinder shock absorber, and when the shock absorber D expands or contracts, the free piston 11 expands or contracts the air chamber G to compensate for the volume of the rod 2 moving in and out of the cylinder 1.
  • the configuration for this volume compensation can also be changed as appropriate.
  • the reservoir may be used to compensate for the volume of the rod 2 moving in and out of the cylinder 1.
  • the reservoir may be formed in a tank separate from the cylinder 1.
  • the shock absorber D may also be configured as a double-rod shock absorber in which the piston 3 is attached to the center of the rod 2 and the ends of the rod 2 protrude outside the cylinder 1 from both ends of the cylinder 1.
  • the rod 2 is cylindrical and has a reduced outer diameter at the tip. It has a small diameter section 2a with the smallest diameter at the tip, a large diameter section 2b with an outer diameter larger than that of the small diameter section 2a and located above the small diameter section 2a in FIG. 2, a step section 2c located at the boundary between the small diameter section 2a and the large diameter section 2b, a screw section 2d located on the outer periphery of the tip of the small diameter section 2a, and four through holes 2e, 2f, 2g, and 2h that are located at positions offset from each other above the screw section 2d of the small diameter section 2a in FIG. 2 and communicate between the inside and outside of the small diameter section 2a.
  • the small diameter portion 2a of the rod 2 is fitted with the valve seat member 20, valve body 21, spacer 22 and valve stopper 23 of the extension side sub-valve EV, the spacer 24, the partition member 25, the valve seat member 26, valve body 27, spacer 28 and valve stopper 29 of the compression side sub-valve CV, the main valve stopper 6, the compression side main valve 5, the piston 3 and the extension side main valve 4, in that order, and secured by a piston nut 33 screwed into the threaded portion 2d at the tip of the small diameter portion 2a.
  • the piston 3 is annular and fixed to the outer periphery of the small diameter portion 2a of the rod 2, and is in sliding contact with the inner periphery of the cylinder 1, dividing the inside of the cylinder 1 into an expansion side chamber R1 on the upper side in Figure 1 and a compression side chamber R2 on the lower side in Figure 1.
  • the piston 3 is also provided with an expansion side passage 3a and a compression side passage 3b that connect the expansion side chamber R1 and the compression side chamber R2.
  • the extension-side main valve 4 which is annular and fits around the small diameter portion 2a of the rod 2 to open and close the extension-side passage 3a, is stacked at the lower end of the piston 3 in FIG. 2.
  • the extension-side main valve 4 is a laminated leaf valve made of multiple stacked annular plates, and its inner periphery is fixed to the small diameter portion 2a of the rod 2 to allow bending on the outer periphery. When the extension-side main valve 4 is seated on the lower end of the piston 3, it closes the outlet end of the lower end of the extension-side passage 3a.
  • extension-side passage 3a When the outer periphery is bent and separated from the piston 3, it opens the extension-side passage 3a and provides resistance to the flow of liquid from the extension-side chamber R1 to the compression-side chamber R2 through the extension-side passage 3a.
  • the extension-side main valve 4 is seated on the piston 3 to block the extension-side passage 3a against the flow of liquid from the compression-side chamber R2 to the extension-side chamber R1.
  • the compression side main valve 5 which is annular and fits around the outer periphery of the small diameter portion 2a of the rod 2 to open and close the compression side passage 3b, is stacked on the upper end of the piston 3 in FIG. 2.
  • the compression side main valve 5 is a laminated leaf valve made of multiple stacked annular plates, and its inner periphery is fixed to the small diameter portion 2a of the rod 2 to allow bending on the outer periphery.
  • the compression side main valve 5 When the compression side main valve 5 is seated on the upper end of the piston 3, it closes the outlet end of the upper end of the compression side passage 3b, and when the outer periphery is bent and separated from the piston 3, it opens the compression side passage 3b and provides resistance to the flow of liquid from the compression side chamber R2 to the extension side chamber R1 through the compression side passage 3b.
  • the compression side main valve 5 is seated on the piston 3 to block the compression side passage 3b against the flow of liquid from the extension side chamber R1 to the compression side chamber R2.
  • a main valve stopper 6 is stacked above the compression side main valve 5 in FIG. 2.
  • the main valve stopper 6 abuts against the side opposite the piston of the compression side main valve 5 to support the compression side main valve 5 and prevent excessive stress from acting on the compression side main valve 5, thereby protecting the compression side main valve 5.
  • the extension side sub-valve EV as a damping valve has a valve seat member 20, a valve body 21, and an orifice O1 provided in the valve body 21, as shown in Figure 2.
  • the valve seat member 20 is annular and includes a partition body 20a in the shape of a disk with a hole that fits onto the outer periphery of the small diameter portion 2a, an annular opposing seat portion 20b that protrudes downward from the outer periphery of the lower end of the partition body 20a in FIG. 2, a plurality of ports 20c that are provided on the same circumference and on the inner side of the opposing seat portion 20b at the lower end of the partition body 20a in FIG.
  • a window 20d that is an annular recess that is connected to the outlet end of each port 20c at the lower end of the partition body 20a in FIG. 2, an annular valve seat 20e that protrudes downward from between the opposing seat portion 20b and the port 20c at the lower end of the partition body 20a in FIG. 2, and an annular inner seat portion 20f that is provided on the inner periphery of the window 20d.
  • the opposing seat 20b surrounds the outer periphery of the annular valve seat 20e with a gap from the partition body 20a, and protrudes downward from the lower end of the annular valve seat 20e.
  • the height of the opposing seat 20b is higher than the annular valve seat 20e when viewed from the partition body 20a, and the height difference between the opposing seat 20b and the annular valve seat 20e is at least higher than the axial thickness of the leaf valve 21a of the valve body 21 described later.
  • the inner circumference of the valve body 21 is a fixed end and the outer circumference is a free end, so the annular valve seat 20e is provided on the inner circumference side that is the fixed end side of the valve body 21 in the radial direction with respect to the opposing seat 20b in the valve seat member 20.
  • the height of the seat surface that is the lower end surface of the inner circumference seat 20f in FIG. 2 is higher than the height of the seat surface that is the lower end surface of the annular valve seat 20e in FIG. 2, and is lower than the opposing seat 20b.
  • the opposing seat 20b and the annular valve seat 20e protrude in the axial direction relative to the partition body 20a, and an annular recess is formed between the opposing seat 20b and the annular valve seat 20e.
  • the annular valve seat 20e is provided on the inner circumference side of the opposing seat 20b, and the height of the opposing seat 20b is higher than the annular valve seat 20e as described above, the opposing seat 20b and the annular valve seat 20e may be integrally provided to protrude in the axial direction from the partition body 20a without having an annular recess between them.
  • the valve body 21 is composed of three leaf valves 21a, 21b, and 21c, the inner periphery of which is fixed to the small diameter portion 2a as a fixed end and the outer periphery of which is allowed to flex as a free end.
  • the valve body 21 is overlapped with the lower end of the partition body 20a of the valve seat member 20 in FIG. 2 and fixed to the outer periphery of the small diameter portion 2a.
  • the valve body 21 is made up of a first leaf valve 21a that is annular, elastic, and located at the top in FIG. 2, a second leaf valve 21b that is annular, elastic, and stacked on the side opposite the valve seat member of the first leaf valve 21a and has the same inner and outer diameters as the first leaf valve 21a, and a third leaf valve 21c that is annular, elastic, and stacked on the side opposite the valve seat member of the second leaf valve 21b and has the same inner and outer diameters as the first leaf valve 21a.
  • the first leaf valve 21a is annular and has a hole 21a1 penetrating in the axial direction.
  • the peripheral surface of the outer periphery which is the free end, faces the opposing seat portion 20b and faces the annular valve seat 20e with a gap in the axial direction.
  • the valve can seat on the annular valve seat 20e.
  • the second leaf valve 21b is annular and is stacked on the opposite valve seat member side of the first leaf valve 21a and has a notch 21b1 that opens from the outer periphery, which is the free end, and communicates with the hole 21a1.
  • the notch 21b1 is configured to have a plurality of arc-shaped portions 21b2 provided on the same circumference of the second leaf valve 21b and a straight portion 21b3 that opens from the outer periphery of the leaf valve 21b and leads to the arc-shaped portion 21b2.
  • the third leaf valve 21c is annular and is stacked on the opposite side of the valve seat member to the second leaf valve 21b.
  • the space connected to the port 20c on the valve seat member side of the valve body 21 is connected to the expansion side chamber R1 on the side opposite the valve seat member of the valve body 21 by the hole 21a1 and the notch 21b1, and the top and bottom of the straight portion 21b3 at the notch 21b1 in FIG. 2 are blocked by the first leaf valve 21a and the third leaf valve 21c, leaving an opening on the outer periphery of the second leaf valve 21b of the straight portion 21b3, and the straight portion 21b3 functions as an orifice O1.
  • the first leaf valve 21a of the valve body 21 faces the opposing seat 20b in the radial direction, and faces the annular valve seat 20e in the axial direction with a gap because the inner peripheral seat 20f is higher than the annular valve seat 20e.
  • the outer peripheral surface of the free end of the first leaf valve 21a of the valve body 21 faces the inner peripheral surface of the opposing seat 20b of the valve seat member 20 in the radial direction with a small gap between them, so that when the first leaf valve 21a faces the opposing seat 20b, the gap between the first leaf valve 21a and the opposing seat 20b is extremely small, making it difficult for liquid to pass through the gap, and this state is the state in which the extension side sub-valve EV is closed. In this state in which the extension side sub-valve EV is closed, liquid is allowed to pass almost only through the orifice O1.
  • the expansion side sub-valve EV can open and close the port 20c, so it is not necessary for the entire outer peripheral surface of the first leaf valve 21a to face the entire inner peripheral surface of the opposing seat portion 20b in the radial direction.
  • the spacer 22, which is stacked on the side opposite the valve seat member of the valve body 21, has an outer diameter smaller than that of the valve body 21 and is fixedly fixed to the small diameter portion 2a.
  • the spacer 22 is composed of one annular plate, but may be composed of multiple annular plates. Therefore, when the valve body 21 receives pressure from the upper side of the valve seat member 20 in FIG. 2, attempting to pass through the port 20c downward, the outer periphery of the spacer 22 is deflected downward in FIG. 2 with the outer periphery of the spacer 22 as a fulcrum.
  • the outer periphery of the first leaf valve 21a is no longer directly opposite the inner periphery of the opposing seat portion 20b in the radial direction and is shifted downward relative to the opposing seat portion 20b, and the area of the flow path formed by the gap between the first leaf valve 21a and the opposing seat portion 20b is increased according to the amount of deflection of the first leaf valve 21a.
  • the expansion side sub-valve EV opens, and the expansion side sub-valve EV provides resistance to the flow of liquid while allowing the liquid to flow through the gap via the valve body 21.
  • valve body 21 When the valve body 21 receives pressure from the liquid passing upward through port 20c from below the valve seat member 20 in Fig. 2, it bends the outer periphery upward in Fig. 2, using the inner peripheral edge of the inner peripheral seat portion 20f of the valve seat member 20 as a fulcrum. When the valve body 21 bends by a preset amount or more, the first leaf valve 21a seats on the annular valve seat 20e and closes port 20c.
  • the extension side sub-valve EV functions as a damping valve that opens to allow the liquid flowing in one direction through the port 20c while providing resistance, and conversely, it can also function as a check valve that closes to block the liquid flowing in the other direction through the port 20c.
  • the expansion side sub-valve EV allows liquid to flow from the lower side to the upper side through the orifice O1 until the valve body 21 bends toward the valve seat member and the third leaf valve 21c faces the opposing seat 20b in the radial direction.
  • the amount of bending until the valve body 21 abuts against the annular valve seat 20e when functioning as a check valve and the amount of bending until the third leaf valve 21c faces the opposing seat 20b can be adjusted by setting the height of the seating surfaces of the inner seating surface 20f and the annular valve seat 20e, but the amount of bending may also be adjusted by interposing a spacer between the inner seating surface 20f and the valve body 21. When a spacer is used, the height of the seating surface of the inner seating surface 20f may be made lower than the height of the seating surface of the annular valve seat 20e, and the amount of bending may be adjusted by the number of stacked spacers.
  • valve stopper 23 is laminated on the side of the spacer 22 opposite the valve seat member, and when the valve body 21 is significantly deflected, it comes into contact with the valve body 21 to support the valve body 21 and prevent excessive stress from acting on the valve body 21, thereby protecting the valve body 21.
  • a spacer 24 is stacked below the valve stopper 23 in FIG. 2.
  • the spacer 24 is formed in a bottomed cylindrical shape, with a hole 24a at the bottom that allows the small diameter portion 2a of the rod 2 to pass through, and a notch 24c that connects the inside and outside of the cylindrical portion 24b.
  • the cylindrical portion 24b faces radially through holes 2e and 2f in the small diameter portion 2a, and the inside of the cylindrical portion 24b is connected to the inside of the rod 2. Since the spacer 24 is arranged on the side opposite the valve seat member of the valve body 21, the upper end of the spacer 24 may be used as a valve stopper and the valve stopper 23 may be eliminated.
  • the partition member 25 is cylindrical with a bottom, and has a hole 25a at the bottom that allows the small diameter portion 2a of the rod 2 to pass through.
  • the open side faces upward and is placed on the lower end of the spacer 24 in FIG. 2, and the cylindrical portion is fitted into the outer periphery of the valve seat member 20 to be fixed to the outer periphery of the small diameter portion 2a of the rod 2.
  • the partition member 25 has an outer diameter smaller than the inner diameter of the cylinder 1, and forms an annular gap between the cylinder 1 and the partition member 25, and separates the space R3 within the expansion side chamber R1 together with the valve seat member 20.
  • the space R3 is connected to the expansion side chamber R1 via a port 20c provided in the valve seat member 20, and is connected to the compression side chamber R2 through the notch 24c of the spacer 24, the through holes 2e and 2f of the small diameter portion 2a, and the inside of the rod 2.
  • the port 20c, the space R3, the through holes 2e, 2f, and the inside of the rod 2 form an expansion-side sub-passage EP as a damping passage that connects the expansion-side chamber R1 and the compression-side chamber R2.
  • the expansion-side sub-passage EP thus configured connects the expansion-side chamber R1 and the compression-side chamber R2 in parallel with the expansion-side passage 3a provided in the piston 3. Therefore, the expansion-side sub-valve EV is provided in the expansion-side sub-passage EP that bypasses the expansion-side passage 3a and connects the expansion-side chamber R1 and the compression-side chamber R2.
  • the compression side sub-valve CV as a damping valve is disposed between the partition member 25 and the compression side main valve 5 and is attached to the outer periphery of the small diameter portion 2a.
  • the compression side sub-valve CV includes a valve seat member 26 and a valve body 27.
  • the valve seat member 26 is annular and includes a perforated disk-shaped partition body 26a that fits onto the outer periphery of the small diameter portion 2a, an annular opposing seat portion 26b that protrudes downward from the outer periphery of the lower end of the partition body 26a in FIG. 2, an annular groove 26c provided on the inner periphery of the partition body 26a, a plurality of ports 26d that open from the inner periphery side of the opposing seat portion 26b at the lower end of the partition body 26a in FIG. 2 and communicate with the annular groove 26c, and It is equipped with a window 26e, which is an annular recess at the lower end in FIG.
  • annular valve seat 26f that is provided at the lower end of the partition body 26a in FIG. 2 between the opposing seat 26b and the port 26d and protrudes downward
  • annular inner seat 26g provided on the inner periphery of the window 26e
  • multiple restriction portions 26h that protrude in the axial direction from within the window 26e of the partition body 26a.
  • the opposing seat 26b surrounds the outer periphery of the annular valve seat 26f and protrudes downward from the lower end of the annular valve seat 26f.
  • the height of the opposing seat 26b is higher than the annular valve seat 26f when viewed from the partition body 26a, and the height difference between the opposing seat 26b and the annular valve seat 26f is at least higher than the axial thickness of the leaf valve 27a of the valve body 27 described later.
  • the inner circumference of the valve body 27 is a fixed end and the outer circumference is a free end, so the annular valve seat 26f is provided on the inner circumference side that is the fixed end side of the valve body 27 in the radial direction with respect to the opposing seat 26b in the valve seat member 26.
  • the height of the seat surface that is the lower end surface of the inner circumference seat 26g in FIG. 2 is higher than the height of the seat surface that is the lower end surface of the annular valve seat 26f in FIG. 2 and lower than the opposing seat 26b.
  • the opposing seat 26b and the annular valve seat 26f protrude axially from the partition body 26a as one unit, and the annular valve seat 26f is provided adjacent to the inside of the opposing seat 26b.
  • the annular valve seat 26f may be spaced apart from the opposing seat 26b on the inner circumference side of the opposing seat 26b and protrude from the partition body 26a.
  • valve seat member 26 is provided with a plurality of restricting portions 26h that protrude in the axial direction from the inner circumferential side, which is the lower end of the partition body 26a and is closer to the fixed end of the valve body 27 than the annular valve seat 26f in the radial direction.
  • the restricting portions 26h are provided between the annular valve seat 26f and the inner circumferential seat portion 26g and between the ports 26d, 26d in the window 26e in the circumferential direction of the partition body 26a, but the installation position of the restricting portions 26h can be arbitrarily changed in design as long as they are between the annular valve seat 26f and the inner circumferential seat portion 26g and do not interfere with the port 26d.
  • the shape of the restricting portions 26h when the valve seat member 26 is viewed in the axial direction may be arc-shaped or circular, and can be arbitrarily changed in design.
  • the restricting portion 26h is provided between the ports 26d, 26d, in order to avoid the port 26d, but it is preferable to provide the restricting portion 26h at equal intervals on the same circumference in order to uniformly support the valve body 27 in the circumferential direction when the valve body 27 is deflected toward the valve seat member, but it does not necessarily have to be provided at equal intervals on the same circumference as long as it can support the valve body 27.
  • the height of the seat surface of the restricting portion 26h is the same as the seat surface of the annular valve seat 26f, but it may be lower than the annular valve seat 26f as long as the valve body 27 can be supported by abutting against the leaf valve 27a when seated on the annular valve seat 26f.
  • the valve body 27 is composed of a leaf valve 27a and two elastic annular plates 27b and 27c that are stacked on the leaf valve 27a.
  • the inner periphery of the valve body 27 is fixed to the small diameter portion 2a as a fixed end, and the outer periphery, which is allowed to flex, is a free end.
  • the valve body 27 is stacked on the lower end of the partition body 26a of the valve seat member 26 in FIG. 2 and fixed to the outer periphery of the small diameter portion 2a.
  • the valve body 27 is made up of a leaf valve 27a that is annular, elastic, and located at the top in FIG. 2, has a notch 27a1 that opens from the outer periphery that is the free end, an annular plate 27b that is annular, elastic, and stacked on the side opposite the valve seat member of the leaf valve 27a, and has a smaller outer diameter than the leaf valve 27a, and an annular plate 27c that is annular, elastic, and stacked on the side opposite the valve seat member of the annular plate 27b, and has a smaller outer diameter than the annular plate 27b.
  • valve body 27 the space connected to the port 26d on the valve seat member side of the valve body 27 is connected to the expansion side chamber R1 on the side opposite the valve seat member of the valve body 27 by a notch 27a1 provided in the leaf valve 27a, and this notch 27a1 functions as an orifice O2.
  • valve body 27 When the valve body 27 thus configured is placed on the inner peripheral seat 26g of the partition body 26a of the valve seat member 26, the leaf valve 27a of the valve body 27 faces the opposing seat 26b in the radial direction, and since the inner peripheral seat 26g is higher than the annular valve seat 26f, it faces the annular valve seat 26f with a gap in the axial direction.
  • the outer peripheral surface of the free end of the leaf valve 27a of the valve body 27 faces the inner peripheral surface of the opposing seat 26b of the valve seat member 26 with a small gap in the radial direction, so when the leaf valve 27a faces the opposing seat 26b, the gap between the leaf valve 27a and the opposing seat 26b is extremely small, making it difficult for liquid to pass through the gap, and this state is the state in which the compression side sub-valve CV is closed.
  • the compression side sub-valve CV is closed in this way, the passage of liquid is permitted almost exclusively through the orifice O2.
  • the compression side sub-valve CV can open and close the port 26d, so it is not necessary for the entire outer peripheral surface of the leaf valve 27a to face the entire inner peripheral surface of the opposing seat portion 26b in the radial direction.
  • the spacer 28 stacked on the side opposite the valve seat member of the valve body 27 has an outer diameter smaller than that of the annular plate 27c arranged on the side closest to the valve seat member of the valve body 27, and is fixed immovably to the small diameter portion 2a.
  • the spacer 28 is composed of one annular plate, but may be composed of multiple annular plates. Therefore, when the valve body 27 receives pressure from the upper side of the valve seat member 26 in FIG. 2, which is passing through the port 26d downward, the outer periphery of the spacer 28 is deflected downward in FIG. 2, with the outer periphery of the spacer 28 as a fulcrum.
  • the outer periphery of the leaf valve 27a is no longer directly opposite the inner periphery of the opposing seat portion 26b in the radial direction, and is shifted downward with respect to the opposing seat portion 26b, and the area of the flow path formed by the gap between the leaf valve 27a and the opposing seat portion 26b is increased according to the amount of deflection of the leaf valve 27a.
  • the compression side sub-valve CV opens, and the compression side sub-valve CV provides resistance to the flow of liquid while allowing the liquid to flow through the gap via the valve body 27.
  • the leaf valve 27 is seated on the annular valve seat 26f when it receives pressure from the liquid passing through the port 26d upward from the lower part of the valve seat member 26 in FIG. 2, and the outer periphery of the valve seat member 26 is deflected upward in FIG. 2 with the inner periphery of the inner periphery seat portion 26g of the valve seat member 26 as a fulcrum.
  • the valve body 27 is deflected by a preset amount or more, the leaf valve 27a is seated on the annular valve seat 26f, and the port 26d is maintained in communication with the expansion-side chamber R1 only via the orifice O2.
  • the compression-side sub-valve CV communicates the expansion-side chamber R1 with the port 26d via the orifice O2, and limits the flow path area.
  • the contraction side sub-valve CV as a damping valve allows the liquid to flow by bending the free end of the valve body 27 toward the side opposite the valve seat member to open, and conversely, when liquid flows from the bottom to the top of port 26d in FIG.
  • the contraction side sub-valve CV functions as a damping valve that opens to allow and provide resistance to the flow of liquid flowing in one direction through port 26d, and conversely, functions as a check valve that activates only the orifice O2 for the flow of liquid flowing in the other direction through port 26d.
  • the compression side sub-valve CV allows liquid to flow from the lower side to the upper side through the port 26d until the valve element 27 bends towards the valve seat member and seats on the annular valve seat 26f.
  • the amount of deflection which is the amount of deflection until the valve element 27 abuts on the annular valve seat 26f, can be adjusted by setting the height of the seating surfaces of the inner circumferential seat portion 26g and the annular valve seat 26f, but the amount of deflection may also be adjusted by interposing a spacer between the inner circumferential seat portion 26g and the valve element 27.
  • the height of the seating surface of the inner circumferential seat portion 26g may be made lower than the height of the seating surface of the annular valve seat 26f, and the amount of deflection may be adjusted by the number of stacked spacers.
  • valve stopper 29 is laminated on the side of the spacer 28 opposite the valve seat member, and when the valve body 27 is significantly deflected, it comes into contact with the valve body 27 to support the valve body 27 and prevent excessive stress from acting on the valve body 27, thereby protecting the valve body 27.
  • the annular groove 26c formed on the inner periphery of the valve seat member 26 faces the through holes 2g, 2h provided in the small diameter portion 2a in the radial direction, so that the port 26d is connected to the inside of the rod 2. Therefore, the expansion side chamber R1 is connected to the compression side chamber R2 through the port 26d, the through holes 2g, 2h, and the inside of the rod 2.
  • the port 26d, the through holes 2g, 2h, and the inside of the rod 2 form a compression side sub-passage CP as a damping passage that connects the expansion side chamber R1 and the compression side chamber R2.
  • the compression side sub-passage CP configured in this manner is parallel to the compression side passage 3b provided in the piston 3 and connects the expansion side chamber R1 and the compression side chamber R2. Therefore, the compression side sub-valve CV is provided in the compression side sub-passage CP that bypasses the compression side passage 3b and connects the expansion side chamber R1 to the compression side chamber R2.
  • a cylindrical rotary valve 12 is housed within the rod 2, with its outer circumferential surface in sliding contact with the inner circumferential surface of the rod 2, allowing it to rotate circumferentially within the rod 2.
  • the rotary valve 12 has holes 12a, 12b, 12c, and 12d that communicate between the inside and outside at positions that can face the through holes 2e, 2f, 2g, and 2h, respectively, and when rotated by a control rod 13 inserted into the rod 2, the degree of communication between the through holes 2e and 12a, the through holes 2f and 12b, the through holes 2g and 12c, and the through holes 2h and 12d can be changed, and the through holes 2e, 2f, 2g, and 2h can be blocked without facing the holes 12a, 12b, 12c, and 12d.
  • the rotary valve 12 can adjust the area of each of the four flow passages consisting of the through hole 2e and the hole 12a, the through hole 2f and the hole 12b, the through hole 2g and the hole 12c, and the through hole 2h and the hole 12d depending on the circumferential rotation position relative to the rod 2, and can adjust the resistance to the flow of hydraulic oil passing through the flow passages.
  • the control rod 13 is driven by a rotary actuator (not shown), such as a stepping motor attached to the tip of the rod 2, but the rotary actuator may be housed within the rod 2.
  • the rotary valve 12 is provided in the middle of the expansion-side sub-passage EP and the compression-side sub-passage CP, and when rotated by the control rod 13, the degree of communication (flow path area) between the holes 12a, 12b, 12c, 12d and the corresponding through holes 2e, 2f, 2g, 2h can be changed to change the resistance to the flow of liquid passing through the expansion-side sub-passage EP and the compression-side sub-passage CP.
  • the rotary valve 12 has two holes 12a, 12b for adjusting the flow area of the expansion-side sub-passage EP and two holes 12c, 12d for adjusting the flow area of the compression-side sub-passage CP, but the number of holes can be changed as desired according to the setting of the maximum flow area.
  • the number of through holes provided in the rod 2 may be set in accordance with the number of holes provided in the rotary valve 12.
  • the holes 12a, 12b, 12c, and 12d provided in the rotary valve 12 may be offset in the circumferential direction, and the through holes 2e, 2f, 2g, and 2h provided in the rod 2 may also be provided at appropriate positions corresponding to the holes 12a, 12b, 12c, and 12d.
  • the hole 12b and the through hole 2f may be connected when the hole 12a and the through hole 2e provided in the middle of the expansion side sub-passage EP face each other and communicate with each other, or the hole 12b and the through hole 2f may be set to face each other at a timing different from the timing when the hole 12a and the through hole 2e face each other. This also applies to the relationship between the holes 12c, 12d and the through holes 2g, 2h provided in the middle of the compression side sub-passage CP.
  • the damping valves, EV (rebound side sub-valve) and CV (compression side sub-valve), and D (shock absorber) are configured as described above.
  • the operation of D (rebound side sub-valve) and CV (compression side sub-valve), and D (shock absorber) is described below.
  • the piston 3 moves upward in the cylinder 1 in FIG. 1 to compress the expansion-side chamber R1.
  • the expansion-side sub-passage EP and the compression-side sub-passage CP are in communication with each other through the rotary valve 12, the liquid in the expansion-side chamber R1 compressed by the upward movement of the piston 3 tries to move to the expanding compression-side chamber R2 through the expansion-side sub-passage EP together with the expansion-side passage 3a provided in the piston 3.
  • the expansion speed of the shock absorber D when the expansion speed of the shock absorber D is in the extremely low speed range and close to 0, the pressure in the expansion-side chamber R1 rises, but the differential pressure between the pressure in the expansion-side chamber R1 and the pressure in the compression-side chamber R2 does not reach the opening pressure of the expansion-side main valve 4, so the expansion-side main valve 4 does not open and keeps the expansion-side passage 3a closed.
  • the compression-side main valve 5 receives the pressure of the expansion-side chamber R1 from the back side and closes the compression-side passage 3b.
  • the valve body 27 remains closed with the outer circumferential surface of the leaf valve 27a facing the inner circumferential width of the facing seat 26b, keeping the flow area in the annular gap between the valve body 27 and the facing seat 26b extremely small, and the expansion side chamber R1 is connected to the port 26d almost exclusively by the orifice O2.
  • the extension main valve 4 When the extension speed of the shock absorber D is in the very low speed range and close to zero, the extension main valve 4 also keeps the extension passage 3a closed, so the liquid in the extension chamber R1 passes through the orifice O1 in the extension sub-passage EP and through the orifice O2 in the compression sub-passage CP to move to the compression chamber R2 because the extension sub-valve EV and the compression sub-valve CV remain closed.
  • the valve body 27 of the compression side sub-valve CV is deflected by the pressure in the expansion side chamber R1 and seats on the annular valve seat 26f of the valve seat member 26, so that the port 26d remains in communication with the expansion side chamber R1 only through the orifice O2, allowing the liquid to pass through the compression side sub-passage CP, but the flow path area of the expansion side sub-valve EV is larger than the flow path area of the orifice O2.
  • the damping force is generated mainly by the valve body 21 and the opposing seat portion 20b of the extension side sub-valve EV, and the flow path area of the extension side sub-valve EV increases in accordance with the increase in piston speed, so that the damping force characteristic of shock absorber D becomes a characteristic with a smaller slope than the damping force characteristic line in the very low speed range, as shown in FIG. 4.
  • valve body 21 bends significantly and abuts against the valve stopper 23, maximizing the flow area in the annular gap between the opposing seat 20b, while the extension-side main valve 4 bends and moves away from the piston 3 to open the extension-side passage 3a.
  • the liquid moves from the extension-side chamber R1 to the compression-side chamber R2 through the gap between the extension-side main valve 4 and the piston 3, and the increase in piston speed increases the amount of bending of the extension-side main valve 4, and the flow area in the gap between the extension-side main valve 4 and the piston 3 becomes larger than the flow area in the annular gap between the valve body 21 and the opposing seat 20b in the extension-side sub-valve EV. Therefore, the shock absorber D generates a damping force mainly due to the resistance that the extension-side main valve 4 provides to the flow of liquid.
  • the damping force characteristic of the shock absorber D becomes a characteristic that generates a damping force with a slope that is almost constant with respect to the increase in piston speed, as shown in FIG. 4.
  • the resistance to the flow of liquid passing through the extension side sub-passage EP can be adjusted, so the damping force of the shock absorber D in this embodiment can be adjusted.
  • the shock absorber D when the shock absorber D is extended, the rod 2 retreats from the cylinder 1, but the free piston 11 moves upward in FIG. 2 within the cylinder 1 to expand the air chamber G and compensate for the volume of the rod 2 that retreats from the cylinder 1.
  • the contraction speed of the shock absorber D when the contraction speed of the shock absorber D is in the extremely low speed range and close to 0, the pressure in the compression side chamber R2 rises, but the pressure difference between the pressure in the compression side chamber R2 and the pressure in the expansion side chamber R1 does not reach the opening pressure of the compression side main valve 5, so the compression side main valve 5 does not open and keeps the compression side passage 3b closed.
  • the expansion side main valve 4 receives the pressure of the compression side chamber R2 from the back side and closes the expansion side passage 3a.
  • valve body 21 when the contraction speed of the shock absorber D is in the very low speed range and close to zero, the valve body 21 remains closed with the outer peripheral surface of the first leaf valve 21a facing the inner circumference of the opposing seat portion 20b within the axial width range, keeping the flow path area in the annular gap between the valve body 21 and the opposing seat portion 20b extremely small, and the expansion side chamber R1 is connected to the port 20c almost exclusively by the orifice O1.
  • the compression side main valve 5 When the contraction speed of shock absorber D is in the very low speed range and close to zero, the compression side main valve 5 also keeps the compression side passage 3b closed, so that the liquid in the compression side chamber R2 passes through the orifice O2 in the compression side sub-passage CP and through the orifice O1 in the extension side sub-passage EP to move to the extension side chamber R1 because the expansion side sub-valve EV and the compression side sub-valve CV remain closed.
  • the liquid passes through the annular gap between the leaf valve 27a and the opposing seat portion 26b in the compression side sub-valve CV, passes through the compression side sub-passage CP, and moves from the compression side chamber R2 to the expansion side chamber R1.
  • the valve body 21 in the expansion side sub-valve EV bends under the pressure in the compression side chamber R2 and seats on the annular valve seat 20e of the valve seat member 20.
  • the outer periphery of the third leaf valve 21c stacked on the side opposite the valve seat member of the second leaf valve 21b with the notch 21b1 faces the opposing seat 20b in the radial direction, so that the annular gap between the third leaf valve 21c and the opposing seat 20b is extremely small, making it difficult for liquid to pass through the gap between the third leaf valve 21c and the opposing seat 20b. Therefore, when the contraction speed of the shock absorber D reaches a low speed range, the expansion side sub-valve EV blocks the opening of the port 26d to prevent liquid from passing through the compression side sub-passage CP.
  • the compression side sub-valve CV increases the flow path area to be larger than the flow path area of orifice O2
  • the expansion side sub-valve EV functions as a check valve to block the expansion side sub-passage EP.
  • shock absorber D when the piston speed during the contraction operation of shock absorber D increases and changes from the very low speed range to the low speed range, the damping force is generated mainly by the valve body 27 and the opposing seat portion 26b of the compression side sub-valve CV, and the flow path area of the compression side sub-valve CV increases in response to the increase in piston speed, so that the damping force characteristics of shock absorber D have a slope that is smaller than the damping force characteristic line in the very low speed range, as shown in Figure 4.
  • valve body 27 bends significantly and abuts against the valve stopper 29, maximizing the flow path area in the annular gap between the opposing seat 26b, while the compression side main valve 5 bends and moves away from the piston 3 to open the compression side passage 3b.
  • the liquid moves from the compression side chamber R2 to the extension side chamber R1 through the gap between the compression side main valve 5 and the piston 3, and the increase in piston speed increases the amount of bending of the compression side main valve 5, and the flow path area in the gap between the compression side main valve 5 and the piston 3 becomes larger than the flow path area in the annular gap between the valve body 27 and the opposing seat 26b in the compression side sub-valve CV. Therefore, the shock absorber D generates a damping force mainly due to the resistance that the compression side main valve 5 provides to the flow of liquid.
  • the damping force characteristic of the shock absorber D becomes a characteristic that generates a damping force with a slope that is almost constant with respect to the increase in piston speed, as shown in FIG. 4.
  • the resistance to the flow of liquid passing through the compression side sub-passage CP can be adjusted, so the damping force of the shock absorber D in this embodiment can be adjusted.
  • the extension side sub-valve EV and the compression side sub-valve CV as damping valves in this embodiment are provided with annular valve bodies 21, 27 with an inner periphery as a fixed end and an outer periphery as a free end that is allowed to bend relative to the fixed end, annular opposing seats 20b, 26b that are annular and face at least a portion of the circumferential surface on the free end side of the valve bodies 21, 27, valve seat members 20, 26 having ports 20c, 26d provided radially closer to the fixed end side of the valve bodies 21, 27 than the opposing seats 20b, 26b, and orifices O1, O2 provided in the valve bodies 21, 27 to communicate between the valve seat member side and the non-valve seat member side of the valve bodies 21, 27 when the valve bodies 21, 27 and the opposing seats 20b, 26b are directly opposed to each other.
  • extension side sub-valve EV and the compression side sub-valve CV as the damping valves configured in this way, even if the free ends of the valve bodies 21, 27 and the opposing seats 20b, 26b are directly opposite each other, liquid can pass through the orifices O1, O2 in places other than the gaps between the valve bodies 21, 27 and the opposing seats 20b, 26b. Therefore, with the extension side sub-valve EV and the compression side sub-valve CV as the damping valves, even if the flexural rigidity of the valve bodies 21, 27 is set high, the damping force does not become excessive when the expansion/contraction speed of the shock absorber D is in the very low speed range.
  • extension side sub-valve EV and the compression side sub-valve CV as the damping valves in the present embodiment described above open and open the ports 20c and 26d when the valve bodies 21 and 27 bend toward the side opposite the valve seat member, and seat on the annular valve seats 20e and 26f when the valve bodies 21 and 27 bend toward the valve seat member and function as check valves.
  • the annular valve seats 20e and 26f may be eliminated and the ports 20c and 26d may be opened whether the valve bodies 21 and 27 bend toward the valve seat member or toward the side opposite the valve seat member.
  • valve seat members 20, 26 in the extension side sub-valve EV and the compression side sub-valve CV as damping valves in this embodiment are provided with annular valve seats 20e, 26f that are provided between the opposing seat portions 20b, 26b and the ports 20c, 26d and axially face the valve bodies 21, 27, on which the valve bodies 21, 27 can be seated and separated.
  • the valve bodies 21, 27 bend to open the port 20c, 26d and provide resistance to the flow of liquid passing through the port 20c, 26d, and when pressure is applied to the valve bodies 21, 27 toward the valve seat members 20, 26 side, the valve bodies 21, 27 seat on the annular valve seats 20e, 26f to block the port 20c, 26d. Therefore, it can function as a damping valve for the flow of liquid passing through the port 20c, 26d in one direction and as a check valve for the flow of liquid passing through the port 20c, 26d in the other direction.
  • valve body 21 in the extension side sub-valve EV as a damping valve in this embodiment includes a first leaf valve 21a which is annular and has an outer periphery, which is the peripheral surface of the free end, facing the opposing seat portion 20b and has a hole 21a1 penetrating in the axial direction so that it can be seated on and removed from the annular valve seat 20e, a second leaf valve 21b which is annular and stacked on the anti-seat member side of the first leaf valve 21a and has a notch 21b1 that opens from the outer periphery, which is the free end, and communicates with the hole 21a1, and a third leaf valve 21c which is annular and stacked on the anti-seat member side of the second leaf valve 21b, and an orifice O1 is formed by the notch 21b1.
  • the valve body 21 when the valve body 21 bends toward the opposite side of the valve seat member 20 so as to move away from the valve seat member 20, the valve body 21 functions as a damping valve by providing resistance to the flow of liquid passing through the gap between the valve body 21 and the opposing seat portion 20b, and when the valve body 21 bends toward the valve seat member side and seats on the annular valve seat 20e, the outer periphery, which is the free end of the third leaf valve 21c, faces the opposing seat portion 20b directly, minimizing the gap between the third leaf valve 21c and the opposing seat portion 20b and making it difficult for liquid to pass through the gap, so that when it functions as a check valve, the port 20c can be substantially closed even if it has an orifice O1.
  • the port 20c when it functions as a check valve, the port 20c can be substantially closed even if it has an orifice O1, so that the damping force characteristics of the extension side of the shock absorber D can be set independently.
  • valve body 27 in the compression side sub-valve CV as a damping valve may be annular, with the peripheral surface of the outer periphery, which is the free end, facing the opposing seat portion 26b, and may have a notch 27a1 opening from the outer periphery, which is the free end, and the orifice O2 may be formed by the notch 27a1.
  • the depth of the notch 27a1 may be set so that the tip of the notch 27a1 does not face the port 26d when the valve body 27 is seated on the annular valve seat 26f.
  • the valve body 27 receives the pressure of the expansion side chamber R1 from the back side and seats on the annular valve seat 26f, the communication between the notch 27a1 and the port 26d is cut off, and the port 26d can be blocked by the valve body 27.
  • the orifice O2 is formed by providing a notch 27a1 on the free end of the valve body 27, it is also possible to completely block the port 26d by the valve body 27.
  • the orifice may be formed by a groove 26b1 provided in the opposing seat portion 26b of the valve seat member 26.
  • the extension side sub-valve EV and the compression side sub-valve CV function as damping valves as check valves, if there is no need to completely close the port 26d with the valve body 27, and the port 26d is opened whether the valve body 27 is deflected toward the valve seat member side or the opposite valve seat member side, it is sufficient to provide the groove 26b1 that forms the orifice in the opposing seat portion 26b, which makes it easier to install the orifice.
  • the inner periphery of the valve body 21, 27 is the fixed end and the outer periphery is the free end, and the outer periphery of the valve body 21, 27 is opposed to the inner periphery of the opposing seat 20b, 26b to form the extension side sub-valve EV and the compression side sub-valve CV as damping valves.
  • the damping valve may be formed by forming the outer periphery of the valve body as the fixed end and the inner periphery as the free end, providing an opposing seat on the inner periphery of the valve body, and opposing the inner periphery of the valve body to the outer periphery of the opposing seat.
  • the orifice may be formed by a notch that opens from the inner periphery of the valve body.
  • valve seat member 26 in the compression side sub-valve CV as a damping valve in this embodiment is provided with a restricting portion 26h that is disposed radially closer to the fixed end of the valve body 27 than the annular valve seat 26f, faces the valve body 27 in the axial direction, and abuts against the valve body 27 when the free end of the valve body 27 bends toward the valve seat member by a predetermined amount or more to restrict the bending of the valve body 27.
  • the shock absorber D of this embodiment is equipped with a cylinder (outer tube) 1, a rod 2 inserted axially movably into the cylinder (outer tube) 1, a shock absorber body A having at least an extension side chamber (working chamber) R1 and a compression side chamber (working chamber) R2 through which liquid flows as the rod 2 moves relative to the cylinder (outer tube) 1, and an extension side sub-valve EV and a compression side sub-valve CV as damping valves provided between the extension side chamber (working chamber) R1 and the compression side chamber (working chamber) R2.
  • the shock absorber D configured in this manner is equipped with the extension side sub-valve EV and the compression side sub-valve CV, it is possible to prevent the damping force from becoming excessive in the extremely low speed range of the expansion and contraction speed of the shock absorber D, and to improve the ride comfort of the vehicle.
  • the damping force characteristics of the expansion side of the shock absorber D can be set independently, and the compression side sub-valve CV generates a damping force when the liquid flows from the compression side chamber R2 to the expansion side chamber R1, and the orifice O2 provides resistance when the liquid flows from the expansion side chamber R1 to the compression side chamber R2, so the damping force characteristics of the compression side of the shock absorber D can be set independently.
  • the extension side sub-valve EV and the compression side sub-valve CV as damping valves are provided in the extension side sub-passage EP and the compression side sub-passage CP that bypass the extension side passage 3a and the compression side passage 3b of the piston 3, and the damping valves are arranged in parallel with the extension side main valve 4 and the compression side main valve 5 of the piston 3, but the damping valves may be used as the extension side main valve or the compression side main valve.
  • the extension side sub-valve EV and the compression side sub-valve CV as damping valves are provided in the extension side sub-passage EP and the compression side sub-passage CP that bypass the extension side passage 3a and the compression side passage 3b of the piston 3, but only the extension side sub-valve EV or only the compression side sub-valve CV may be provided in the shock absorber D.
  • the two working chambers are the expansion side chamber R1 and the compression side chamber R2, but if the shock absorber D is a twin-tube shock absorber that has an outer shell as an outer tube around the outer periphery of the cylinder and a reservoir between the cylinder and the outer shell, a damping valve DV may be provided between the compression side chamber and the reservoir. Therefore, the port in the damping valve may connect the expansion side chamber R1 and the compression side chamber R2, or may connect the compression side chamber and the reservoir.
  • the speed range in which damping force is generated mainly by the extension side sub-valve EV and the compression side sub-valve CV as damping valves is the low speed range, but the speeds that divide very low speed, low speed, and high speeds that exceed low speed can be set as desired by the designer.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Fluid-Damping Devices (AREA)
PCT/JP2024/004472 2023-03-09 2024-02-09 減衰バルブおよび緩衝器 Ceased WO2024185398A1 (ja)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017180550A (ja) * 2016-03-29 2017-10-05 日立オートモティブシステムズ株式会社 緩衝器
JP2018076920A (ja) * 2016-11-09 2018-05-17 トヨタ自動車株式会社 ショックアブソーバ
JP2019183918A (ja) * 2018-04-06 2019-10-24 Ｋｙｂ株式会社 バルブ及び緩衝器
JP2021076139A (ja) * 2019-11-06 2021-05-20 Ｋｙｂ株式会社 バルブ及び緩衝器

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017180550A (ja) * 2016-03-29 2017-10-05 日立オートモティブシステムズ株式会社 緩衝器
JP2018076920A (ja) * 2016-11-09 2018-05-17 トヨタ自動車株式会社 ショックアブソーバ
JP2019183918A (ja) * 2018-04-06 2019-10-24 Ｋｙｂ株式会社 バルブ及び緩衝器
JP2021076139A (ja) * 2019-11-06 2021-05-20 Ｋｙｂ株式会社 バルブ及び緩衝器

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