US3742819A - Telescopic piston-cylinder assembly for hydraulic machines and machine components - Google Patents

Telescopic piston-cylinder assembly for hydraulic machines and machine components Download PDF

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Publication number
US3742819A
US3742819A US00114935A US3742819DA US3742819A US 3742819 A US3742819 A US 3742819A US 00114935 A US00114935 A US 00114935A US 3742819D A US3742819D A US 3742819DA US 3742819 A US3742819 A US 3742819A
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United States
Prior art keywords
cylinder
piston
unit
assembly
seating
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Expired - Lifetime
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US00114935A
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English (en)
Inventor
L Freese
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NEW INUENT
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NEW INUENT
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0044—Component parts, details, e.g. valves, sealings, lubrication
    • F01B3/0052—Cylinder barrel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B1/00—Reciprocating-piston machines or engines characterised by number or relative disposition of cylinders or by being built-up from separate cylinder-crankcase elements
    • F01B1/06—Reciprocating-piston machines or engines characterised by number or relative disposition of cylinders or by being built-up from separate cylinder-crankcase elements with cylinders in star or fan arrangement
    • F01B1/0641—Details, component parts specially adapted for such machines
    • F01B1/0644—Pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B15/00—Reciprocating-piston machines or engines with movable cylinders other than provided for in group F01B13/00
    • F01B15/002—Reciprocating-piston machines or engines with movable cylinders other than provided for in group F01B13/00 having cylinders in star or fan arrangement, the connection of the pistons with the actuated or actuating element being at the outer ends of the cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0082—Details
    • F01B3/0085—Pistons

Definitions

  • ABSTRACT A piston-cylinder assembly is provided, comprising two interengaging sleeve members telescopically extendable and contractable.
  • the assembly has at either end an internal frusto-conical sealing surface for pivotaily engaging a seat having a convex spherical surface, the contact line between the conical sleeve end and the spherical seat thus being a circle.
  • the assembly is intended to be operated by a pressure fluid, primarily hydraulic and of a pressure of 5,0006,000 psig.
  • the tremendous operative force developed is automatically exactly centered between the two spherical seats, in any relative position thereof, without subjecting the sleeve members to tilting moments.
  • By keeping the contact line diameter very close to the diameter of the effective pressure area of the assembly the seating forces are low, and therefore the friction developed during the relative pivot movements between the sleeve members and the seats is low, and yet the sealing is perfect.
  • the present invention relates generally to pressurefluid machines or machine components, particularly hydraulic piston machines such as axial and radial piston machines, but also to machines operating with gaseous media such as pneumatic machines, and such machines components as hydraulic or pneumatic swivel couplings and the like.
  • the working pressure acting on the piston is normally transmitted to the drive shaft of the machine, or a member connected with the shaft, by means of a piston rod, piston shoe or some corresponding machine component.
  • the force transmitting member executes a definite angular movement in relation to the piston. The oblique position of the member during the force transmitting moment brings lateral forces and tilting loads to bear on the piston, resulting in increased friction, increased wear and the risk of binding between both the piston and cylinder and between the piston and the force transmitting member at the common contacting surfaces of these members.
  • the object of the present invention is to provide for hydraulic machines and machine components an assembly, which can be designated a telescopic pistoncylinder assembly, whose main function is to permit the working fluid or pressure fluid of the machine to come into direct contact with the driven or driving shaft thereof (or a member fixedly connected with the shaft) thereby establishing a direct force transmitting connection between the fluid and the shaft without the intermediary of mechanical elements such as pivoted piston rods and the like.
  • the force developed by the pressure fluid is transmitted practically completely to the shaft of the machine hydraulically and the pistoncylinder assembly of the invention can in actual fact, be considered to constitute a movable seal in the hydraulic system.
  • FIG. 1 illustrates a central longitudinal section through a telescopic piston-cylinder assembly constructed in accordance with the invention and forming part of a hydraulic piston machine, and also shows associated seating surfaces
  • FIG. 2 illustrates a part of the embodiment of FIG. 1 in slightly larger scale
  • FIG. 3 is a longitudinal section through a pistoncylinder assembly of the present invention in an embodiment adapted for use in a hydraulic radial piston machine, the parts of which surrounding the assembly have been shown diagrammatically in radial section.
  • the piston-cylinder assembly illustrated in FIG. ll comprises an outer, sleeve-like, rotation--like, rotationsymmetrical cylinder 10 and a piston 12 slidably accomodated therein and being of the same constructional design, i.e. in the form of a rotation-symmetrical sleeve, the piston being sealed in a conventional manner in the cylinder by means of a sealing ring 13.
  • the outer, outwardly turned end portions 14 and 16 of the cylinder and piston, respectively, are provided with seating surfaces 28 and 30 which slidably engage opposing seating surfaces 22 and 24 located on stud-like seating bodies 18 and 20 respectively.
  • the seating surfaces 22 and 24 have a convex spherical shape.
  • the seating surfaces located in the ends 14, 16 of the piston-cylinder assembly are in the form of straight, truncated, internal conical surfaces or cones 28 and 30.
  • the axes of the conical surfaces coincide with the common center axis of the cylinder 10 and piston 12, and their wider ends extend outwardly of the center of the assembly.
  • circle lines 32 can best be seen from FIG. 2, which in slightly larger scale illustrates the right half of the embodiment of FIG. 1, it being assumed that the geometrical conditions are in principle the same at both ends of the piston-cylinder assembly.
  • Half of the cone angle of the conical seating surface 28 of the cylinder 10 is equal to i.e. the cone angle is 27.
  • the conditions are identical at the opposite end of the piston cylinder assembly, i.e. at piston end 16, and the piston 12 will be balanced hydraulically so that its mechanical abutting force against the seating surface 24 of the seating body merely consitutes approximately 1 percent of the total force developed axially by the pressure fluid.
  • the cone angle y and the radius of the part-spherical seating body can, as aforementioned, have other values than those at the cylinder end 14 of the assembly, since obviously the condition for the hydraulic balancing of the assembly as a whole are merely that the contact circles 32 are equal or practically equal at both ends.
  • the second of the three decisive advantages afforded to the inventor is that because of the symmetrical design the described pressure and force conditions will prevail independently of the position of the pistoncylinder assembly 10, 12 in relation to the outer spherical seating bodies 18, 20, i.e. independently of the angles ill and (Il between the center lines 36 of the assembly and the center lines 36 and 40 of the seating bodies 18 and 20 resp., FIG. 1. Irrespective of the angular position of the assembly in relation to the spherical seating bodies at the ends thereof, the resultant force of the forces created by the fluid pressure will always act along the center line of the unit.
  • the third advantage obtained with the pistoncylinder assembly of the present invention is connected with the fact that the seating surface 28 and 30 at the ends of the piston-cylinder assembly have an internally conical configuration.
  • these surfaces can in principle be of another geometrical shape, for example concave spherical surfaces having the same radius as respective outer seating surfaces 22 and 24, this latter shape being perhaps the more conventionally obvious one, wherewith the assembly would still obtain substantially the same functional properties as those aforedescribed.
  • the seating surfaces are concave and arcuate in shape
  • seating surfaces 28 and 30 having a concave spherical configuration must conform extremely acurately with the corresponding convex spherical seating surfaces, in order for the sealing clearances between the surfaces in question to obtain an exact and reproducable geometrical form (parallelitity) and size (clearance gap), a condition which requires expensive and time consuming production methods, finishing, for example, with a lapping operation.
  • an internal conical surface is relatively simple to produce with sufficient accuracy, e.g. by turning and grinding, at same time as relatively moderate toler ances on the diametrical measurements of the cooperating convex, spherical seating surface can be permitted.
  • tolerance can be permitted since deviation in the diameter of the sphere from a nominal measurement only affect the diameter of the contact circle 32, i.e. the degree of hydraulic balancing of the cylinder and piston, but not the geometrical shape and size of the sealing gap, since the tapering surfaces can adjust themselves to the spherical surfaces by mutual axial movements.
  • the ends of the piston-cylinder assembly can be held in engagement with respective outer seating surfaces by means of a coil spring 44 mounted externally of the assembly, the spring being arranged to engage external abutments 46 and 48 on the outer ends of the cylinder and the piston 12 respectively.
  • the ends of the assembly can however, be mechanically held against cooperating outer seatings in other, known ways.
  • the principle construction of the piston-cylinder assembly of the invention illustrated in FIG. 1 also teaches a practical non-motorial application of the assembly. If the outer seating body 18 cooperating with the cylinder 10 is, similarly to the opposing seating body 20, also provided with a through passing passage 27, as indicated with dotted lines, the assembly of the present invention can be used as a hydraulic machine element, e.g. in the form of a swivel or pivotable joint in a high pressure line for hydraulic or pneumatic fluids.
  • FIG. 3 illustrates how a piston-cylinder assembly according to the invention can be applied in a radial piston machine.
  • This machine includes a housing 72, in which a shaft 74'is rotatably mounted.
  • the shaft is provided with an eccentric 76 having a cylindrical surface and the center points of the eccentric are indicated by the references 0 and 0'.
  • the outer cylindrical surface '78 of the machine is provided on the inside thereof with a cylindrical surface 80, against which a seating body 82 bears, the supporting surface of the seating body conforming to the cylindrical surface of the housing, as shown in FIG. 3.
  • the radially inwardly turned surface 84 of the seating body 82 is convex and spherical in shape, and engaging said surface is the internally conical end surface of a piston forming part of a piston-cylinder assembly according to the invention, the cone angle of said conical end surface being 2
  • the interior of the piston-cylinder assembly communicates with the surroundings through a passage 86 arranged centrally in the seating body 82.
  • the opposite, radially inwardly directed end surface of the piston-cylinder assembly i.e., the end surface of the cylinder 92 forming part of the assembly, is shaped to conform with and engage the cylindrical surface of the eccentric 76.
  • the hydraulic conditions are essentially the same with this embodiment as those described in the aforegoing, the fluid pressure prevailing in the assembly acting directly on the surface of the eccentric, and by suitable design and dimensioning of the edge surface of the cylinder abutting the eccentric a high degree of hydraulic balance between the surfaces can be obtained.
  • the hydraulic balance is obtained at the opposing piston end in the manner aforedescribed, the cone angle 27, being adapted according to the radius of the seating surface 84.
  • the piston-cylinder assembly Upon rotation of the shaft 74, the piston-cylinder assembly will execute a pendulum movement around the center of the seating surface 84.
  • the unit 90, 92 presents the same principal and manufacturing advantages as the previously described embodiment of the assembly.
  • the assembly can be used to advantage for machines intended for gaseous working medium, e.g. compressed air motors or compressors.
  • a telescopic piston-cylinder assembly for use with a pressure fluid, comprising:
  • a telescopic unit having first and second bearing surfaces formed on the opposite ends thereof;
  • first and second reaction-force absorbing seat means respectively engaging said first and second bearing surfaces for supporting said unit; said first and second seat means having first and second seating surfaces, respectively, disposed in slidable bearing engagement with said first and second bearing surfaces, respectively, for permitting'angular movement of said unit relative to at least one of said seating surfaces; said telescopic unit having a maximum crosssectional pressure area defined by a predetermined diameter, and including a sleeve-like cylinder and a sleeve-like piston slidably received in said cylinder, the opposed ends of said cylinder and sleeve being axially overlapped, the other end of said cylinder and sleeve respectively having said first and second bearingsurfaces thereon;
  • passage means communicating with the interior of said unit for permitting pressure.fluid to be supplied to the interior of said cylinder;
  • said one seating surface being provided with a convex spherical slide surface, and the corresponding one of said first and second bearing surfaces as disposed in engagement with said one seating surface having an internal conical configuration whereby it engages said slide surface substantially along a circular line of contact, said circular line of contact between said slide surface and the corresponding bearing surface having a diameter substantially equal to or only slightly smaller than said predetermined diameter.
  • annular surface between the periphery of the maximum cross-sectional pressure area of the unit and the said circular line of contact is approximately between 0.5 and 2 percent of the total maximum cross-sectional pressure area.
  • An assembly according to claim 1 further including spring means positioned externally of said unit in surrounding relationship to said piston and cylinder for resiliently urging said piston and cylinder in opposite axial direction for maintaining the opposite ends of said unit in secure engagement with said first and second seat means.
  • a telescopic piston-cylinder assembly for a hydraulic machine including a telescopic unit having a sleeve-shaped piston slidably received in a sleeveshaped cylinder to which a pressure medium is introduced, the unit being movably disposed between and supported on a pair of spaced reaction-force absorbing seating surfaces each engaging a respective end of the unit, comprising the improvement wherein at least one of the seating surfaces is provided with a convex spherical slide surface disposed in engagement with the adjacent end of the piston-cylinder unit, said adjacent end of said unit having an internal bearing surface of conical configuration whereby said bearing surface engages said slide surface substantially along a circular line of contact whose diameter is only slightly smaller than the maximum diameter of the active pressure area of the piston-cylinder unit, said pressure area being the interior cross-sectional area of said unit perpendicular to the longitudinal axis of said unit.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Actuator (AREA)
  • Details Of Reciprocating Pumps (AREA)
  • Reciprocating Pumps (AREA)
US00114935A 1970-02-20 1971-02-12 Telescopic piston-cylinder assembly for hydraulic machines and machine components Expired - Lifetime US3742819A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE2183/70A SE343110B (enrdf_load_stackoverflow) 1970-02-20 1970-02-20

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US3742819A true US3742819A (en) 1973-07-03

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US00114935A Expired - Lifetime US3742819A (en) 1970-02-20 1971-02-12 Telescopic piston-cylinder assembly for hydraulic machines and machine components

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US (1) US3742819A (enrdf_load_stackoverflow)
DE (1) DE2107653B2 (enrdf_load_stackoverflow)
GB (1) GB1288704A (enrdf_load_stackoverflow)
SE (1) SE343110B (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4469013A (en) * 1981-04-08 1984-09-04 Oliostip S.P.A. Radial-piston hydraulic motor
EP0266806A3 (en) * 1986-08-11 1988-08-17 Riva Calzoni S.P.A. Hydraulic motor comprising radially arranged, tubular propulsion elements
US5022310A (en) * 1989-03-07 1991-06-11 Stewart Robert M Fluid power transmission
WO2007059866A1 (de) * 2005-11-25 2007-05-31 Bosch Rexroth Ag Axialkolbenmaschine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3430362A1 (de) * 1984-08-17 1986-02-27 Paul Pleiger Maschinenfabrik GmbH & Co KG, 5810 Witten Radialkolbenmotor
DE3526496A1 (de) * 1985-07-24 1987-01-29 Linde Ag Axialkolbenmaschine in schwenkschlittenbauform
WO2013087666A1 (de) * 2011-12-15 2013-06-20 Robert Bosch Gmbh Hydrostatische axialkolbenmaschine

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1187642A (en) * 1914-10-17 1916-06-20 Max J Milz Pipe-joint
US1500921A (en) * 1919-06-21 1924-07-08 Bramson Mogens Louis Flexible pipe line
US1679276A (en) * 1926-10-27 1928-07-31 Republic Brass & Mfg Co Plumbing fixture
US2146133A (en) * 1936-06-01 1939-02-07 Waterbury Tool Co Power transmission
US2157692A (en) * 1936-04-29 1939-05-09 Waterbury Tool Co Power transmission
US2955850A (en) * 1956-11-15 1960-10-11 Strachan & Henshaw Ltd Pipe coupling having telescopic and lateral compensating means
US3040716A (en) * 1958-06-28 1962-06-26 Hahn Theodor Piston engines
US3108543A (en) * 1959-06-23 1963-10-29 Licentia Gmbh Fluid motor or pump
US3507522A (en) * 1964-12-15 1970-04-21 Atomenergi Ab Pipe joint
DE1811156A1 (de) * 1968-11-27 1970-06-11 Kessler & Co Tech Chem Gmbh Raeumlich beweglicher Laengenausgleicher fuer Rohrleitungen

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1187642A (en) * 1914-10-17 1916-06-20 Max J Milz Pipe-joint
US1500921A (en) * 1919-06-21 1924-07-08 Bramson Mogens Louis Flexible pipe line
US1679276A (en) * 1926-10-27 1928-07-31 Republic Brass & Mfg Co Plumbing fixture
US2157692A (en) * 1936-04-29 1939-05-09 Waterbury Tool Co Power transmission
US2146133A (en) * 1936-06-01 1939-02-07 Waterbury Tool Co Power transmission
US2955850A (en) * 1956-11-15 1960-10-11 Strachan & Henshaw Ltd Pipe coupling having telescopic and lateral compensating means
US3040716A (en) * 1958-06-28 1962-06-26 Hahn Theodor Piston engines
US3108543A (en) * 1959-06-23 1963-10-29 Licentia Gmbh Fluid motor or pump
US3507522A (en) * 1964-12-15 1970-04-21 Atomenergi Ab Pipe joint
DE1811156A1 (de) * 1968-11-27 1970-06-11 Kessler & Co Tech Chem Gmbh Raeumlich beweglicher Laengenausgleicher fuer Rohrleitungen

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4469013A (en) * 1981-04-08 1984-09-04 Oliostip S.P.A. Radial-piston hydraulic motor
EP0266806A3 (en) * 1986-08-11 1988-08-17 Riva Calzoni S.P.A. Hydraulic motor comprising radially arranged, tubular propulsion elements
US5022310A (en) * 1989-03-07 1991-06-11 Stewart Robert M Fluid power transmission
WO2007059866A1 (de) * 2005-11-25 2007-05-31 Bosch Rexroth Ag Axialkolbenmaschine

Also Published As

Publication number Publication date
DE2107653A1 (de) 1971-09-02
DE2107653B2 (de) 1975-11-27
SE343110B (enrdf_load_stackoverflow) 1972-02-28
GB1288704A (enrdf_load_stackoverflow) 1972-09-13

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