US3808950A - Flow-control arrangements in axial-cylinder pumps - Google Patents

Flow-control arrangements in axial-cylinder pumps Download PDF

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Publication number
US3808950A
US3808950A US00305408A US30540872A US3808950A US 3808950 A US3808950 A US 3808950A US 00305408 A US00305408 A US 00305408A US 30540872 A US30540872 A US 30540872A US 3808950 A US3808950 A US 3808950A
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United States
Prior art keywords
barrel
cylinder
sleeve
port
port plate
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Expired - Lifetime
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US00305408A
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English (en)
Inventor
A Davies
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Sauer Danfoss Swindon Ltd
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Plessey Handel und Investments AG
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Assigned to PLESSEY OVERSEAS LIMITED reassignment PLESSEY OVERSEAS LIMITED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: PLESSEY HANDEL UND INVESTMENTS AG, GARTENSTRASSE 2, ZUG, SWITZERLAND
Assigned to PLESSEY COMPANY PLC THE reassignment PLESSEY COMPANY PLC THE CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE SEPT. 23, 1981. Assignors: PLESSEY COMPANY LIMITED THE
Assigned to SUNDSTRAND HYDRATEC LIMITED CHENEY MANOR, AN ENGLISH COMPANY reassignment SUNDSTRAND HYDRATEC LIMITED CHENEY MANOR, AN ENGLISH COMPANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: PLESSEY OVERSEAS LIMITED, AN ENGLISH COMPANY
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Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F04B1/2014—Details or component parts
    • F04B1/2035—Cylinder barrels

Definitions

  • ABSTRACT A fluid-tight seal between each cylinder bore in the barrel of a swash-plate pump and the corresponding port bore in a port plate rotating with the barrel is established by a sleeve, which is accommodated in aligned counterbores of the two bores, provided at the mutually adjacent end faces of the barrel and port plate, and which is sealed in each of these counter bores by a separate compressed O-ring seal, common rotation of the port plate with the barrel being ensured by means independent of the sleeves.
  • the sleeve has sufficient play in the counter bores to allow for slight angular displacement between the respective end faces of the cylinder barrel and the stationary valve face of, for example, a valve plate.
  • the 0- rings are accommodated in annular recesses at each of the two ends of the sleeve and are compressed axially between washers resting respectively against the bottom shoulders of the two counter bores so that the resilience of the O-rings provides an axial thrust force urging the port plate into contact with the valve plate.
  • This invention relates to axial-cylinder pumps of the kind, thereinafter called the kind specified, in which a number of cylinders are arranged in a so-called cylinder barrel which is mounted for rotation about its axis in a pump housing with the cylinder bores extending substantially parallel to the axis of rotation and being spaced at equal radii round the latter and generally uniformly distributed round the axis, and in which the rotation of the barrel relative to the housing is utilised for producing periodic reciprocation of a piston in each cylinder for each revolution of the barrel, and in which furthermore control of the flow between each cylinder and a high-pressure and a low-pressure port respectively in accordance with the direction of movement of the piston is achieved by co-operation of a port, communicating with each cylinder and arranged in an end face of the barrel, with high-pressure and low-pressure ports in the stationary housing which, by means of mutually sliding sealing surfaces, respectively associated
  • the actuation of the pistons is achieved by co-operation of an extension of each piston with the surface of a track which is stationary in the housing, and which is inclined to a plane perpendicular to the axis of rotation in accordance with the desired stroke of the pistons.
  • the term pump when used in the present specification, is intended, unless the context otherwise requires, to be broad enough to include a machine whether it is to be operated to displace fluid when mechanically driven (pumps in the narrower sense) or for use to produce mechanical power when actuated by fluid pressure (operation as a fluidpressure motor).
  • the present invention has for an object to avoid the necessity of providing, in order to minimise leakage losses across the end face of the sleeve, such a sliding end-surface seal and thus the necessity of maintaining high axial contact pressurewhich results in the transmission of an undesirable force to the port plate.
  • Another object is to provide an axial-cylinder pump having a port plate, rotatable with the cylinder barrel, which is capable of reliable operation under conditions of relatively large angular displacement of the axis of the cylinder barrel relative to the axis of the port plate.
  • fluid-tight connection between each cylinder and its port in the port plate is established by a sleeve which extends into substantially aligned bores coaxial with the cylinder in the cylinder barrel and with its port in the port plate respectively, in each of which bores the sleeve is capable of a small amount of axial and swivel movement;
  • the port plate is coupled for common rotation with the cylinder barrel independently of the presence of these sleeves, and the sleeve is sealed in each of these bores by a sealing ring of resiliently compressible material, which is compressed in a circumferential groove or shoulder portion of one of the co-operating circumferential wall surfaces of the sleeve and bore so that it maintains, due to its resiliently compressed state, sealing contact with the other of the said co-operating surfaces.
  • each sealing ring is accommodated in an annular chamber formed within the bore by an outwardly projecting circumferential shoulder determining a reduced-diameter portion of the sleeve near the adjacent end thereof, and is compressed between the face of this annular shoulder and an opposing face formed or supported by the cylinder barrel and port plate respectively, so that the resilient compression of each sealing ring is utilised, in addition to its use for maintaining circumferential seal in the appropriate bore, for also maintaining some axial sealing force between the sealing face of the port plate and the cooperating stationary face which contains the highpressure and low-pressure ports of the pump housing.
  • FIG. 1 is an elevation of the pump in section through the axis of the cylinder barrel, taken in the direction of maximum inclination of the swash-plate surface to the face of the port plate,
  • FIG. 2 is a scrap section drawn to a larger scale and shows details of the arrangement of one of the sealing sleeves, and
  • FIG. 3 is a plan view of part of the port plate with a thrust washer.
  • a socalled cylinder barrel 2 is mounted for rotation about its axis in a housing 1.
  • the barrel 2 is connected for common rotation with a shaft 3, which is supported in the housing 1 by bearings 4 and 5.
  • the latter of these is a ball bearing of a kind capable of transmitting axial thrust as well as radial forces
  • the shaft 3 is provided with a flange 6 which co-operates with an end face of the cylinder barrel 2 to transmit axial thrust from the latter to the pump housing 1 through a further'flange 6a resting against the ball bearing 5.
  • the cylinder barrel 2 is provided with a number of cylinder bores 7 uniformly distributed round the axis of the shaft 3 at equal distances therefrom and extending substantially parallel to the shaft.
  • Each cylinder bore contains a piston 8 having a ballended extension 8a which, in a well-known way, cooperates with a track surface on a so-called swash plate 9 through the medium of a so-called slipper 10, a separate slipper 10 being provided on the extension of each piston member 8 for sliding co-operation with the track surface 1 1 of the swash-plate 9.
  • This surface is inclined to a plane at right angles to the axis of the shaft 3 so that, during each revolution of the cylinder barrel 2, each piston, if its slipper 10 is maintained in contact with the surface 11, will perform one reciprocation in its cylinder.
  • the swash plate 9 is equipped with a retainer ring 12 which co-operates with a shoulder 13 of each slipper 10.
  • port passages 14 and 15 of the pump housing 1 are continued in a so-called valve plate 16 to form the ports proper in the valve plate 16 of which the surface that faces the end of the cylinder barrel is highly finished, and a so-called port plate 17, having a similarly finished surface for co-operation with this surface of the valve plate 16, is provided with an individual cylinder port 18 for each cylinder bore 7 of the cylinder barrel 2.
  • This port plate 17 is coupled to the shaft 3 so as to rotate jointly with the barrel 2 but is slightly spaced axially from this barrel to leave a narrow gap 19, and a small amount of plate is also provided between the central bore 17a of the port plate and the shaft 3, to allow the lower end face 2a of the barrel 2 to assume a slight angle of inclination to the adjacent end face of the port plate 17 without interfering with the surface contact between the port plate 17 and valve plate 16.
  • a substantially leak-free connection between each cylinder bore 7 and its associated port 18 in the port plate 1'7 is however assured by the interposition, between the cylinder barrel 2 and the port plate 17, of a connector sleeve 20 for each cylinder as will be described further below.
  • a force, produced by hydraulic pressure and tending to hold the port plate 17 in contact with the valve plate 16 is provided by making the ports 18 in the port-plate kidney-shaped so as to be substantially narrower in the radial direction of the barrel than the diameter of the cylinder bores 7 and counterbore 21, and byconfining the area of which the distributed pressure of leakage fluid acts between the contacting sealing surfaces of the valve plate 16 and port plate 17, to a relatively narrow land 27 surrounding each of the ports 8. This is achieved by the provision in the end face of the port plate 17 of drained recesses 25, 26 which encircle this land.
  • Each connector sleeve 20 is accommodated for part of its length in a cylindrical counterbore 21 which is provided in the port plate 17 to continue the port 18 axially through the surface facing the cylinder barrel 2, and whose diameter is substantially larger than the width of the port 18 transversely of its direction of revolving movement about the barrel axis.
  • the other end of the sleeve 20 is accommodated in a counterbore 7a at the adjacent end of the associated cylinder bore 7 of the cylinder barrel, this counter-bore being separated from the cylinder bore 7 proper by an annular shoulder 22, and a thrust washer 29 is preferably interposed between the shoulder 22 and the sleeve 20 as described further below.
  • the dimensions of the sleeve 20 are such as to leave some axial clearance between the ends of the sleeve 20 and the bottom of the counter-bore 21 and/or shoulder 22 or thrust washer at the top of the counter-bore 7a, and to leave also some radial clearance at the circumference of the sleeve 20, thus allowing the sleeve 20 to accommodate angular displacement of the barrel 2 relative to the port plate 17 in the manner above indicated.
  • two seals are formed in the counter-bores 21 and 7a respectively by O-rings 23 and 24 of rubber or other resiliently compressible material.
  • O-rings are accommodated in suitable annular recesses of the sleeve 20, which respectively face the wall of the counter-bore 21 in the port plate 17. and the wall of the sleeve-accommodation counterbore 7a of the cylinder bore 7.
  • the O-rings are arranged to be compressed in their cross-section during the assembly of the device, so as to be applied to the wall of the said bores with sufficient force to ensure a liquid-tight seal.
  • the recesses accommodating the O-rings 23 and 24 are open at the end faces of the sleeve 20 as illustrated, and the O-rings 23 and 24 being so dimensioned in their cross-section as to be not only compressed in the radial direction of the sleeve 20 but to be also compressed in the longitudinal direction of the latter, between the shoulder forming the end face of the recess accommodating each O-ring and the shoulder 22 or thrustwasher 29 which restrains the axial movement of this O-ring towards the cylinder bore 7.
  • the O-rings 23 and 24 in addition to their scaling function, also act as thrust springs to provide a resilient force applying the end face of the port plate 17 to the co-operating surface of the valve plate 16 independently of any hydraulic pressure.
  • the length 18a of each port 18 of the port plate 17 in-the direction of its movement round the barrel axis is approximately equal to the diameter of the cylinder bore 7, as will be seen more clearly in PK 2.
  • the shoulder formed by the counter-bore 21 is used to support a substantially rigid thrust washer 28 of a radial width just sifficient to provide such adequate shoulder surface for the O-ring 24 while the diameter of its central aperture is at least approximately equal to the diameter of the axial passage 20a of the sleeve 20 so as to be clear of the port 18 except for the above-mentioned end areas 18b.
  • This arrangement makes it possible to keep the excess in diameter of the counterbores 7a in the cylinder barrel 2 over the diameter of the cylinder bore 7 at a minimum, thus minimising the hydrostatic thrust force which acts on the shoulder 22 between the bore 7 and counterbore 7a of the cylinder barrel 2 to urge the barrel away from the valve plate 16, and which must be taken-up by the bearing 5.
  • the thrust ring adjacent to that O-ring, or both thrust rings may be formed integral with the sleeve 20, so that the sleeve will butt against the shoulder 22 and/or the bottom of the bore 21, the O-ring in question being accommodated in a groove of the thus modified sleeve.
  • port plate 17 instead of being driven by a shaft connection as described, could be driven from the cylinder barrel 2, for example, by means of suitably arranged dowels.
  • An axial-cylinder pump comprising a pump housing, a cylinder barrel mounted in said housing for rotation about an axis of the barrel and having a plurality of cylinder bores extending parallel to said axis at equal radial distances therefrom, a piston in each cylinder, piston-actuating means operable during rotation of the barrel to produce periodic reciprocation of each piston in its associated cylinder, a port plate arranged coaxially with the barrel for common rotation therewith and having one end face adjacent to but slightly spaced axially from, one end face of the barrel and a second, oppositely directed face, said port plate having port bores, one for each cylinder and each communicating at said one face of the port plate with its associated cylinder and terminating at said second face of the port plate in a port for periodic alternate communication, as the barrel rotates, with ports in a valve face provided in the housing, said barrel having communication bores respectively communicating with each cylinder, and each port of the port plate having a communication bore aligned with one of said communication bores of the barrel, a sealing means
  • An axial-piston pump as claimed in claim 2 including an annular abutment plate supported on, and extending in a radial direction, the shoulder formed by the counterbore in the barrel.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Details Of Reciprocating Pumps (AREA)
US00305408A 1971-11-13 1972-11-10 Flow-control arrangements in axial-cylinder pumps Expired - Lifetime US3808950A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5284271A GB1398272A (en) 1971-11-13 1971-11-13 Flow-control arrangements in axial-cylinder pumps

Publications (1)

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US3808950A true US3808950A (en) 1974-05-07

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US00305408A Expired - Lifetime US3808950A (en) 1971-11-13 1972-11-10 Flow-control arrangements in axial-cylinder pumps

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US (1) US3808950A (it)
JP (1) JPS4858403A (it)
AU (1) AU4856672A (it)
BE (1) BE791148A (it)
CA (1) CA966009A (it)
DE (1) DE2255156A1 (it)
ES (1) ES408674A1 (it)
FR (1) FR2160157A5 (it)
GB (1) GB1398272A (it)
IT (1) IT970428B (it)
NL (1) NL7214995A (it)
SE (1) SE7214717L (it)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3980003A (en) * 1975-02-07 1976-09-14 Caterpillar Tractor Co. Variable hydrostatic bearing between barrel and head of axial piston units
US4286503A (en) * 1977-03-24 1981-09-01 Stefan Fule Machine of the axial piston pump type which can be used as a pump or as a motor
US4793239A (en) * 1978-10-25 1988-12-27 Karl Eickmann Axial piston motor or pump with an arrangement to thrust the rotor against a bearing of the shaft
US5214994A (en) * 1992-01-15 1993-06-01 Caterpillar Inc. Seal ring with attached biasing means
WO1993014298A1 (en) * 1992-01-15 1993-07-22 Caterpillar Inc. An axial piston fluid translating unit with sealed barrel plate
US20070028608A1 (en) * 2004-02-11 2007-02-08 George Kadlicko Rotary hydraulic machine and controls
US20150078930A1 (en) * 2012-03-30 2015-03-19 Mitsubishi Heavy Industries, Ltd. Fluid pressure pump
CN112576470A (zh) * 2020-12-10 2021-03-30 山东泰丰智能控制股份有限公司 一种轴向柱塞泵回程盘的辅助机构

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS525227B2 (it) * 1973-12-12 1977-02-10
IT1082397B (it) * 1977-04-05 1985-05-21 Gherner Lidio Motore idraulico a pistoni assiali
JPS5554679A (en) * 1978-10-16 1980-04-22 Japan Steel Works Ltd:The Slant plate type axial piston pump-motor
JPS5773867A (en) * 1980-10-25 1982-05-08 Honda Motor Co Ltd Multi-plunger type hydraulic apparatus
JPS58128477A (ja) * 1982-01-25 1983-08-01 Hitachi Constr Mach Co Ltd 液圧回転機
JPS6165080A (ja) * 1984-09-05 1986-04-03 Hitachi Constr Mach Co Ltd 液圧回転機
DE4301134C2 (de) * 1993-01-18 1995-05-18 Danfoss As Hydraulische Axialkolbenmaschine
DE4424607A1 (de) * 1994-07-13 1996-01-18 Danfoss As Hydraulische Axialkolbenmaschine
DK3070329T3 (da) * 2013-11-13 2019-06-03 Eco Sistems Watermakers S L Hydraulisk aksial stempelpumpe med en svævende ophængt roterende tromle

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2969810A (en) * 1955-12-27 1961-01-31 Edward C Dudley Wobble plate pump
US3124079A (en) * 1964-03-10 Jxanjacquxs j joyer
US3175510A (en) * 1962-10-16 1965-03-30 Amato Michael A D Variable displacement pump

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3124079A (en) * 1964-03-10 Jxanjacquxs j joyer
US2969810A (en) * 1955-12-27 1961-01-31 Edward C Dudley Wobble plate pump
US3175510A (en) * 1962-10-16 1965-03-30 Amato Michael A D Variable displacement pump

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3980003A (en) * 1975-02-07 1976-09-14 Caterpillar Tractor Co. Variable hydrostatic bearing between barrel and head of axial piston units
US4286503A (en) * 1977-03-24 1981-09-01 Stefan Fule Machine of the axial piston pump type which can be used as a pump or as a motor
US4793239A (en) * 1978-10-25 1988-12-27 Karl Eickmann Axial piston motor or pump with an arrangement to thrust the rotor against a bearing of the shaft
GB2276212A (en) * 1992-01-15 1994-09-21 Caterpillar Inc An axial piston fluid translating unit with sealed barrel plate
WO1993014298A1 (en) * 1992-01-15 1993-07-22 Caterpillar Inc. An axial piston fluid translating unit with sealed barrel plate
US5279205A (en) * 1992-01-15 1994-01-18 Caterpillar Inc. Axial piston fluid translating unit with sealed barrel plate
US5214994A (en) * 1992-01-15 1993-06-01 Caterpillar Inc. Seal ring with attached biasing means
GB2276212B (en) * 1992-01-15 1995-04-12 Caterpillar Inc An axial piston fluid translating unit with sealed barrel plate
US20070028608A1 (en) * 2004-02-11 2007-02-08 George Kadlicko Rotary hydraulic machine and controls
US7992484B2 (en) 2004-02-11 2011-08-09 Haldex Hydraulics Corporation Rotary hydraulic machine and controls
US9115770B2 (en) 2004-02-11 2015-08-25 Concentric Rockford Inc. Rotary hydraulic machine and controls
US20150078930A1 (en) * 2012-03-30 2015-03-19 Mitsubishi Heavy Industries, Ltd. Fluid pressure pump
US10788024B2 (en) * 2012-03-30 2020-09-29 Mitsubishi Heavy Industries, Ltd. Fluid pressure pump
CN112576470A (zh) * 2020-12-10 2021-03-30 山东泰丰智能控制股份有限公司 一种轴向柱塞泵回程盘的辅助机构
CN112576470B (zh) * 2020-12-10 2021-07-06 山东泰丰智能控制股份有限公司 一种轴向柱塞泵回程盘的辅助机构

Also Published As

Publication number Publication date
CA966009A (en) 1975-04-15
DE2255156A1 (de) 1973-05-17
AU4856672A (en) 1974-05-09
BE791148A (fr) 1973-03-01
GB1398272A (en) 1975-06-18
NL7214995A (it) 1973-05-15
FR2160157A5 (it) 1973-06-22
JPS4858403A (it) 1973-08-16
SE7214717L (it) 1973-05-14
IT970428B (it) 1974-04-10
ES408674A1 (es) 1975-11-01

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AS Assignment

Owner name: PLESSEY COMPANY PLC THE

Free format text: CHANGE OF NAME;ASSIGNOR:PLESSEY COMPANY LIMITED THE;REEL/FRAME:004236/0441

Effective date: 19820630

Owner name: SUNDSTRAND HYDRATEC LIMITED CHENEY MANOR, SWINDON,

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:PLESSEY OVERSEAS LIMITED, AN ENGLISH COMPANY;REEL/FRAME:004236/0451

Effective date: 19831020