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US3593977A - Self-leveling hydropneumatic shock absorber - Google Patents

Self-leveling hydropneumatic shock absorber Download PDF

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Publication number
US3593977A
US3593977A US801469A US3593977DA US3593977A US 3593977 A US3593977 A US 3593977A US 801469 A US801469 A US 801469A US 3593977D A US3593977D A US 3593977DA US 3593977 A US3593977 A US 3593977A
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United States
Prior art keywords
chamber
cylinder
piston
shock absorber
reservoir
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.)
Expired - Lifetime
Application number
US801469A
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English (en)
Inventor
Erich Hahn
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.)
ThyssenKrupp Bilstein GmbH
Original Assignee
August Bilstein GmbH
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Filing date
Publication date
Application filed by August Bilstein GmbH filed Critical August Bilstein GmbH
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Publication of US3593977A publication Critical patent/US3593977A/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
    • B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
    • B60G17/044—Self-pumping fluid springs

Definitions

  • a first damping chamber (22) partly filled with air and communicating with a surrounding oil reservoir (11), a pumping chamber (23) connected with an inlet from the oil reservoir containing a check valve, an intermediate chamber (29) receiving oil from the pumping chamber through one-way orifices (26) of the partition (24), and a second damping; chamber (16) receiving I oil from the intermediate chamber through one-way passages [54] SELFJEVEUNG HYDROPNEUMATIC SHOCK (31) in the adjoining piston head (4) while also communicat- ABSORBER mg with a fluid space 15) under pressure from a surrounding 10 Claims, 1 Drawing Fig.
  • present invention relates to a self-leveling shock absorber, e.g. for automotive vehicles, wherein a dashpot assembly is urged into an extended position by a hydraulic liquid under pressurefrom an air cushion or similar pressure-accumulating means.
  • a system of this general character has been disclosed in my copending application Ser. No. 699,510 filed Jan. 22, 1968.
  • the piston of the dashpot assembly has'a head subdividing the interior of its cylinder into two compartments which are in restricted two-way communication via narrow orifices in the piston head, one of these compartments being connected with a fluid reservoir via a supply conduit containing cascaded check valves; this fluid-intake compartment is also open toward an annular space in which the hydraulic working liquid is subjected to the pressure of a surrounding air cushion.
  • An object of my presentinvention is to providean improved system of thistcharacter wherein the pumping chamber is not confined to the interior of a hollow piston but is disposed within the larger cylinder space surrounding the piston for more effective fluid delivery with smaller oscillatory amplitudes of the dashpot assembly.
  • Another object of this invention is to provide means in such a system for effectively retarding the discharge of excess hydraulic liquid (elg. oil) from the pumping chamber in the extended position of the assembly, thereby lessening the im pact due to the changeover from the closed to the open state of the regulating or overflow valve upon transition from a relatively contracted to a relatively extended position as a result of the compensatorypumping action or of a reduction in load.
  • excess hydraulic liquid elg. oil
  • a further object is to provide improved damping means effective in the outer dead center position of the expanding and contracting assembly.
  • piston of the dashpot assembly with two axially spaced piston heads which, together with an internal partition on the peripheral cylinder wall, define an annular pumping chamber and an intermediate chamber communicating with each other via one or more one-way passages in the partition, the intermediate chamber in turn being connected by way of similar one-way passages with an adjoining damping chamber formed between a transverse cylinder wall andthe nearer one of the two piston heads.
  • the damping chamber is connected with the fluid reservoirby a set of conduits which include an axially extending bore in the piston rod, this bore containing the aforementioned regulating valve which, as in my prior system, is opened only after the assembly has reached a certain degree of expansion.
  • the liquid in the reservoir may be maintained at approximately'atmospheric pressure, or at a somewhat higher pressure less than that of the main accumulator, by an overlying air volume confined within the closed housing.
  • means may advantageously be provided. for preventing the entry of entrained solids (e.g. metal particles detached from the walls upon prolonged wear) into the narrower portions of the return path, particularly if that path includes a throttling aperture ordiaphragm beyond the regulating valve to slow the reflux of oil from the damping chamber to the reservoir.
  • entrained solids e.g. metal particles detached from the walls upon prolonged wear
  • l provide a second damping space at the: opposite end of the as sembly, i.e., between the piston head bounding the pumping chamber and an end wall of the cylinder penetrated by the piston rod.
  • This damping space may permanently communicate with the reservoir through a port disposed beyond the sweep of the last-mentioned piston head, in contradistinction to the outlet which is unblocked by that'head only in a relatively extended position of the assembly.
  • he assembly when in equilibrium, always operateswith hydraulic liquid circulating from the pumping chamber via the intermediate and damping chambers back to the pumping chamber during part of the oscillating stroke, with a return to the reservoir of excess liquid aspirated into the pumping; chamber on a preceding phase.
  • the shock absorber shown in the drawing comprises a cylindrical housing 1 whose vertical axis coincides with that of a dashpot assembly including a piston rod 3 with two.piston heads 4, 18 in a hydraulic cylinder 2..
  • the top of housing .1 is closed by a cap 1' holding the dashpot assembly in position while leaving clearance for the piston rod 3 which is connected above the housing with a structure 50 to be supported by the shock absorber, generally the chassis of an automotive vehicle.
  • the lower end of. the housing upon another structural element 51 which may form part of the axle housing of one of the wheels of the vehicle, e.g. of a dirigible front wheel thereof,
  • a washer 4'2 overlain by cap 1 bears upon gasket 7 seated in a disc 9 which forms an end wall of both housing 1 and cylinder 2, a packing ring 8 in-an outer peripheral groove of this disc forming an airtight seal between the interior of the housing and the ambient atmosphere.
  • a transverse partition 6 subdivides the annular space between housing 1 and cylinder 2 into two compartments 11 and 15, the upper compartment 11 being partly filled with oil overlain by a confined volume of air 12 under suitable pressure which may be adjusted through a normally closed inlet nipple not shown.
  • a similar air cushion 13 is disposed in the annular space 15 and is bounded by a flexible membrane 14 separating it: from a high-pressure chamber of variable volume which forms part of compartment 15 and communicates via ports 17 with a damping chamber 16 in the lower end of cylinder 2, the latter chamber being bounded by piston head 4 and by a disc 5 on the bottom of housing 1 forming the other end wall of cylinder 2.
  • the air cushion 13 may also be provided with a filling nipple, not shown, for regulating its pressure.
  • the space within cylinder 2 bounded by piston heads 4 and 18 is subdivided into two chambers of variable volume by an internal partition 24 of cylinder 2, the partition-forming ring being locked to the cylinder wall by a deformation 2 thereof
  • These chambers are a pumping chamber 23 between head 18 and partition 24, communicating with the oil reservoir 11 by way of an inlet containing a check valve 28-, and an intermediate chamber 29 between partition 24 and piston head 4 acting as a secondary pumping chamber.
  • a one-way fluid path from chamber 23 to chamber 29 is formed by several orifices 26 in partition 24, these orifices being overlain at their lower ends by a yieldable valve plate 27 under pressure from a spring 44 which is seated on a ring 45 sprung into'an annular groove of the inner cylinder wall.
  • the piston rod 3 is hollow and has an axial bore 33 open toward damping chamber 16; a channel 39 of reduced width extends from the top of that bore outwardly so as to open into pumping chamber 23.
  • a regulating valve 38 firmly seated at the junction of bore '33 with channel 39 comprises a movable plug 37 with a depending stem 36 extending partly into a tube 34 rising from cylinder wall 5, this tube also housing a coil spring 35 which bears upon a boss 36' of stem 36 to urge the valve member 37 against its seat so as to block communication between chambers 16 and 23.
  • Valve 38 has a recess above the seat of plug 37 which contains a throttling diaphragm 40 and a filter screen 41 wedged into the recess below the diaphragm to prevent the clogging of the diaphragm aperture by oil-en trained solids.
  • the assembly will tend to balance itself under varying load conditions at a level substantially coinciding with the incipient venting of damping chamber 16 to reservoir 11 via pumping chamber 23, i.e. the level at which the valve member 37 is unseated by tube 34 while the lower face of piston head 18 just clears the orifice 20, the assembly then'oscillating about that level in response to the normal uncveness of the road. lf the load of the vehicle is increased, the assembly temporarily contracts to cut off the outflow from chamber 15 until sufiicient additional liquid has been pumped into that chamber to compress the air cushion 13 to a degree generating the counterpressure required to restore the normal level.
  • the assembly expands so that the return path from chamber 16 to reservoir 11 is unblocked during most or all of an oscillatory cycle until enough oil has escaped from chamber 16 to restore the balance.
  • the continuity of the pumping action under all operating conditions mitigates the shocks accompanyingthe blocking and unblocking of the outlet 20 of chamber 23, thereby increasing to the comfort of the riders.
  • a shock absorber comprising:
  • a dashpot assembly in said housing including a cylinder rigid with said housing and a piston axially displaceable in said cylinder, said piston having a pair of axially spaced heads, said cylinder having a first end penetrated by said piston, a second end sealed by a transverse wall and an inner an- .nular partition slidably bearing upon said piston at a location between said piston heads, one of said piston heads proximal to said first end defining with said partition an annular pumping chamber of variable volume, the other of said piston heads defining with said partition an annular intermediate chamber of variable volume and with said transverse wall a damping chamber of variable volume;
  • first unidirectionally effective valve means forming a oneway inlet from said reservoir to said pumping chamber
  • said partition and said other'of said piston heads having passages provided with second and third unidirectionally effective valve means, respectively, for letting hydraulic liquid travel from said pumping chamber by way of said intermediate chamber to said damping chamber upon relative reciprocation of said piston and said cylinder in any relative position thereof;
  • conduit means forming a return path for excess liquid from said damping chamber to said reservoir; flow-blocking means in said return path effective in a relatively contracted'position of said dashpot assembly; release means effective in a relatively extended position of said dashpot assembly for deactivating said flow-blocking means; and i pressure-accumulating means for said hydraulic liquid communicating with said damping chamber.
  • shock absorber as defined in claim 7 wherein said pressure-accumulating means comprising an air cushion in said annular space.
  • a shock absorber as defined in claim 7 wherein said housing is provided with an end wall sealing said ring space and forming a damping space within said cylinder between said end wall and said one of said piston heads, said outlet being disposed on said cylinder in the region of said reservoir and portion of said cylinder I

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Damping Devices (AREA)
  • Vehicle Body Suspensions (AREA)
US801469A 1968-02-22 1969-02-24 Self-leveling hydropneumatic shock absorber Expired - Lifetime US3593977A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681655983 DE1655983A1 (de) 1968-02-22 1968-02-22 Hydropneumatisches Federbein mit selbsttaetiger Niveauregulierung,insbesondere fuer Kraftfahrzeuge

Publications (1)

Publication Number Publication Date
US3593977A true US3593977A (en) 1971-07-20

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Family Applications (1)

Application Number Title Priority Date Filing Date
US801469A Expired - Lifetime US3593977A (en) 1968-02-22 1969-02-24 Self-leveling hydropneumatic shock absorber

Country Status (3)

Country Link
US (1) US3593977A (fr)
DE (1) DE1655983A1 (fr)
FR (1) FR2002427A1 (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837444A (en) * 1972-11-17 1974-09-24 F Allinquant Oleopneumatic shock absorbers
JPS51116527A (en) * 1975-06-24 1976-10-14 Maremont Corp Hydraulic spring assisting unit also functioning as automatic levelling buffer
JPS51139019A (en) * 1975-06-24 1976-12-01 Maremont Corp Hydraulic spring assisting unit also functioning as automatic levelling buffer
JPS5248776A (en) * 1975-06-24 1977-04-19 Maremont Corp Automatically damped buffer and supporting unit for fluid spring
US4085925A (en) * 1976-03-31 1978-04-25 Carl Ullrich Peddinghaus Hydro-pneumatic shock absorber
JPS5493518A (en) * 1977-12-28 1979-07-24 Atsugi Motor Parts Co Ltd Hydroopneumatic suspension for car
US4877223A (en) * 1988-09-21 1989-10-31 Jeffrey K. Hackett Load leveling shock absorber
US20040148976A1 (en) * 2003-01-30 2004-08-05 Young-Ho Kim Damper of drum type washing machine
US20060266602A1 (en) * 2003-08-12 2006-11-30 Robertson Graeme K Shock absorber assembly
US20070119672A1 (en) * 2005-11-29 2007-05-31 Fox Factory, Inc. Damping cylinder with annular bladder

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1188407B (de) * 1959-05-12 1965-03-04 Grundig Max Querverschiebliche Kupplung, insbesondere zum Antrieb der Spulenkoerper bei Tonbandgeraeten
US5476161A (en) * 1990-07-24 1995-12-19 University Of Huddersfield Higher Education Corporation Self-energizing, self-levelling controllable damper unit for a vehicle suspension
FR2758601B1 (fr) * 1997-01-20 1999-03-19 Max Sardou Suspension a controle d'assiette integre
JP5077549B2 (ja) * 2007-10-31 2012-11-21 日立オートモティブシステムズ株式会社 油圧緩衝器の製造方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147826A (en) * 1961-11-21 1964-09-08 Ford Motor Co Hydro-pneumatic suspension strut
US3450235A (en) * 1966-06-15 1969-06-17 Hoesch Ag Self-leveling shock absorber

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147826A (en) * 1961-11-21 1964-09-08 Ford Motor Co Hydro-pneumatic suspension strut
US3450235A (en) * 1966-06-15 1969-06-17 Hoesch Ag Self-leveling shock absorber

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837444A (en) * 1972-11-17 1974-09-24 F Allinquant Oleopneumatic shock absorbers
JPS51116527A (en) * 1975-06-24 1976-10-14 Maremont Corp Hydraulic spring assisting unit also functioning as automatic levelling buffer
JPS51139019A (en) * 1975-06-24 1976-12-01 Maremont Corp Hydraulic spring assisting unit also functioning as automatic levelling buffer
JPS5248776A (en) * 1975-06-24 1977-04-19 Maremont Corp Automatically damped buffer and supporting unit for fluid spring
US4085925A (en) * 1976-03-31 1978-04-25 Carl Ullrich Peddinghaus Hydro-pneumatic shock absorber
JPS5493518A (en) * 1977-12-28 1979-07-24 Atsugi Motor Parts Co Ltd Hydroopneumatic suspension for car
US4877223A (en) * 1988-09-21 1989-10-31 Jeffrey K. Hackett Load leveling shock absorber
US7204104B2 (en) * 2003-01-30 2007-04-17 Lg Electronics Inc. Damper of drum type washing machine
US20040148976A1 (en) * 2003-01-30 2004-08-05 Young-Ho Kim Damper of drum type washing machine
US20060266602A1 (en) * 2003-08-12 2006-11-30 Robertson Graeme K Shock absorber assembly
US7513490B2 (en) * 2003-08-12 2009-04-07 Graeme Kershaw Robertson Shock absorber assembly
USRE44609E1 (en) * 2003-08-12 2013-11-26 Graeme Kershaw Robertson Shock absorber assembly
US20070119672A1 (en) * 2005-11-29 2007-05-31 Fox Factory, Inc. Damping cylinder with annular bladder
US20110005877A1 (en) * 2005-11-29 2011-01-13 Fox Factory, Inc. Damping cylinder with annular bladder
US7921974B2 (en) 2005-11-29 2011-04-12 Fox Factory, Inc. Damping cylinder with annular bladder
US8342488B2 (en) 2005-11-29 2013-01-01 Fox Factory, Inc. Damping cylinder with annular bladder

Also Published As

Publication number Publication date
FR2002427A1 (fr) 1969-10-17
DE1655983A1 (de) 1971-07-01

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