US3255673A - Axial piston hydraulic units - Google Patents

Axial piston hydraulic units Download PDF

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Publication number
US3255673A
US3255673A US286317A US28631763A US3255673A US 3255673 A US3255673 A US 3255673A US 286317 A US286317 A US 286317A US 28631763 A US28631763 A US 28631763A US 3255673 A US3255673 A US 3255673A
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United States
Prior art keywords
cylinder block
bores
face
plate
piston
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Expired - Lifetime
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US286317A
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English (en)
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Thoma Hans
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Classifications

    • 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
    • F04B1/122—Details or component parts, e.g. valves, sealings or lubrication means
    • F04B1/124—Pistons
    • F04B1/126—Piston shoe retaining means
    • 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
    • F01B3/0055—Valve means, e.g. valve plate
    • 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
    • F01B3/0064—Machine housing
    • F01B3/0067—Machine housing cylinder barrel bearing means
    • 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
    • F01B3/007—Swash plate
    • 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
    • F01B3/0088—Piston shoe retaining means

Definitions

  • the present invention relates broadly to the art of hydraulic units, more particularly to axial piston hydraulic units of the general type disclosed in German Patent No. 829,553.
  • the invention therefore, specifically relates to certain improvements in hydraulic units of a type which can also be termed swash plate motor or pump units.
  • Such units include axially disposed pistons which have a spherical head to engage a complementary shaped socket on a slipper that bears against a non-rotatable inclined plate generally referred to in the art as a swash plate.
  • the lateral forces produced by the piston against the inclined plate are transmitted by the pistons back to the cylinder block where they are absorbed by appropriate bearings.
  • the fluid flow to and from the axially disposed cylinders is by way of a non-rotating control, or timing plate, formed 'with segmentally shaped inlet or delivery openings or ports. In the known devices the segmentally shaped inlet or delivery ports are in alignment with the piston accommodating bores or cylinders.
  • This mounting also produces a certain excess of pressure that holds the timing plate in intimate contact with the cylinder 'block. This excess pressure acts on the timing plate axially to avoid tilting moments between the timing plate and the adjacent face of the cylinder block, as the pressure against the timing plate from the said ports is located very close to the axis.
  • FIGURE 1 is a section taken on line 11 of FIG- URE 2
  • FIGURE 2 is a plan view of the non-rotating control or timing plate
  • FIGURE 3 is a section taken on line 33 of FIGURE 4 of element 17 which retains the piston heads in a common plane.
  • FIGURE 4 is a plan view of the device of FIGURE 3.
  • FIGURE 5 is a cross-sectional view on an enlarged scale illustrating the timing plate.
  • FIGURE 1 the unit includes a generally cylindrical casing 1 and end closures 2 and 3.
  • a cylindrical block 4 is rotatably mounted in casing 1 on hearings 5 and 6.
  • Bearings '5 and 6 are of a type to positively restrain the cylinder block against axial movement.
  • a plurality (from 5 to 8 bores, for instance) of bores 7, 7', etc. are arranged about the axis of the cylinder block 4 parallel to the axis of the block. The open ends of each of the bores are toward the closure 2.
  • a piston 8 or 8' (one for each bore 7, 7' etc.) is positioned in each bore and is provided with a generally spherical head 9 or 9' etc.
  • slippers 10, 10 are pressed axially outwardly by a retaining plate 11.
  • 'Retaining plate 11 is pressed outwardly 'by a spring 13 pressing inwardly on cylinder block 4 and outwardly on a member 12 having a spherical surface that coacts with a spherical surface on retaining plate 11, so that retaining plate 11 can assume any desired angle with respect to the axis of the cylinder block 4.
  • Slippers 10, 10' are pressed outwardly against a swash plate 14 that is carried by a yoke 15 .rockahle about an axis 1616 so that the inclination of swash plate 14 can be varied to lengthen or shorten the stroke of the pistons.
  • Retaining plate '11 is provided with a plurality of notches 17 each to embrace one slipper 10, '10 etc., each slipper 10, 10' being provided with a groove 18 to receive retaining plate '11. It is seen, therefore, that retaining plate 11 is adapted to bear on slippers 10, 10' in either direction,'and the hook shape of the recesses 17 tends to prevent radial outward movement of the slippers, and therefore the ends of the pistons are retained in axial alignment with the :bores. Also, the lower side of the groove in the slipper may press outwardly or upwardly on the retaining plate.
  • ports 19, 19' that extend inwardly toward the axis of the cylinder block so that the mouths of the'ports opposite closure 3 are clustered within a small circle near the axis of rotation.
  • the lower end of the cylinder block is otherwise solid.
  • the upper end of the cylinder block 4 is provided with a splined bore 20 to receive the driving shaft 21 by which the cylinder block may be rotated. Bore 20 extends only partly into, not through, cylinder block 4.
  • Timing plate 22 seen in FIGS. 1 and 2, has two arcuate or kidney-shaped ports, one for suction 23, one for exhaust 24. These ports are located to come into registry with the ports 19, 19' which lie very near to the axis of rotation.
  • the surface of the timing plate 2 2 is provided with a plane surface 25 at the center of a radius so that it extends radially beyond ports 23 and 24.
  • a circular groove 26 bounds area 25, and radial grooves 27 extend radially from groove 26 outwardly to provide a plurality of lands 28.
  • the surfaces 25 and 28 bear against the rotary cylinder block 4.
  • the lower closure 3 is provided with two bushings 29 and with two bushings '30 extending upwardly into timing plate 22.
  • Bushings 29 and 30 are provided 'with appropriate packings to seal the bushings to the timing plate 22.
  • bores 23, 23'! are provided to accommodate bushings 29 and bores 24', 24" accommodate bushings 30.
  • bushings 29, 29' and 30, 30' connect to inlet and outlet passages 23 and 24 of the timing plate to inlet 31 and outlet 32, respectively. While two bushings may be used, one at each port 23 and 24, it will be noted that, preferably as suggested by. FIG. 2, four bushings are used, that is, two bushings 29 for port 23 and two bushings 30 for port 24.
  • the groove in slipper 10 prevents axial movement of retaining plate 11 with respeet to the piston-slipper assembly so that the slippers 10, 10', etc., are all held to rotate in the plane of retaining plate 11 at all times, whether or not plate 11 is parallel to swash plate 14. It will further be seen that, in the part of the revolution where the port 19 opens as it passes into position over pressure port 24, there will be an upward thrust of fluid pressure which, without the groove 18, will press the piston outwardly so that the slipper and piston would extend above the plate 11. In this device the plate 11, by pressure of the lower or upwardly facing surfaces of grooves 18, 18' is biased upwardly in the direction of the bias of spring '13.
  • the timing or control plate 22 must form a practical seal against the end of the cylinder block 4.
  • the face-to-face contact between the cylinder block and timing plate that can be subject to pressure from the ports is'limited to a small disc at the center of the timing plate. This small area is bounded by annular groove 26.
  • Radial grooves 27 are provided leaving lands 28 to form bearing surfaces to press against the end of the cylinder block. Since the area including the ports is small and located so close to the center of rotation, it cannot develop a significant tendency to cock the timing plate 22 with respect to the cylinder block 4, and the pressures that need to be exerted by springs 37, 38, 39, 40 are therefore reduced.- The land areas 28 give a broad bearing base counteracting any tendency toward cocking that may occur. The real reason for the springs 37, 38, 39 and 40 isnot to provide sealing pressure between the cylinder and timing plate but primarily to retain the plate against the cylinder when the pump is not in operation.
  • timing plate 22 During the time that a piston as it descends to force liquid out of the ports 19, 19 via port 24 served by bushings 30, the only downward pressure on timing plate 22 is The greatest outward vector of force against the web between the two bushings 30, seen in FIG- URE 2, and there is an upward pressure against the shoulders of timing plate 22 overhanging the bushings which will be greater than the downward pressure since the area of the shoulders is greater than the area of the web between the bushings. By making the bushings larger and closer together, this effect maybe augmented. There will, of course, be direct pressure on the timing plate 22 from each cylinder at each end of the pressure stroke during the time ports 19, 19' partly overlap port 24. Similarly, there is a negative pressure between each cylinder and the timing plate at port 23, so that at each end of port 23-there is a negative pressure tending to balance the positive pres sure at the ends of port 24.
  • an axial piston hydraulic unit of the type including a casing, a rotatable cylinder block within the casing, said tive rotation of said cylinder block and casing, said swash plate means being provided with an aperture including the extension of the axis of rotation of said cylinder block,
  • a rotatable shaft drivingly secured to said cylinder block adjacent said swash plate extending outwardly of said casing through said aperture in said swash plate, means operatively secured to each piston end to maintain said piston ends in a common plane
  • said cylinder block having an end face remote from said swash plate constituting a distribution end, ports leading inwardly towardthe axis of rotation of said cylinder block from each of said piston accommodating bores to said distribution end so that said ports at said distribution end are clustered closely about the axis of rotation of said cylinder block, a timing plate having a first face in face-to-face contact with said distribution end of said cylinder block and a second face parallel to said first face, the improvement comprising said timing plate having two kidney-shaped openings in said first face opening toward said-cylinder block opposite said ports in said distribution end of said cylinder block, four bores extending into said timing plate from said second face, said four bores being clustered closely adjacent the extension of the axis of rotation of said cylinder block, said four bores
  • an axial piston hydraulic unit of the type including a casing, a rotatable cylinder block within the casing, said casing having a plurality of piston accommodating bores extending parallel to the axes of rotation of said cylinder block, a piston reciprocably disposed in each of said bores, each having a piston end extending outwardly from said cylinder block, swash plate means mounted in said casing positioned to operate said pistons upon relatively rotation of said cylinder block and easing, said swash plate means being provided with an aperture including the extension of the axis of rotation of said cylinder block, a rotatable shaft drivingly secured to said cylinder block adjacent said swash plate extending outwardly of said casing through said aperture in said swash plate, means operatively secured to each piston end to maintain said piston ends in a common plane, said cylinder block having an end face remote from said swash plate constituting a distribution end, ports leading inwardly toward the axis of rotation of said cylinder block from each of said piston accommodating bores to said
  • an axial piston hydraulic unit of the type including a casing, a rotatable cylinder block within the casing, said casing having a pluralityof piston accommodating bores extending parallel to the axes of rotation of said cylinder block, a piston reciprocably disposed in each of said bores, each having a piston end extending outwardly from said cylinder block, swash plate means mounted in said casing positioned to operate said pistons upon relative rotation of said cylinder block and casing, said swash plate means being provided with an aperture including the extension of the axis of rotation of said cylinder block, a rotatable shaft drivingly secured to said cylinder block adjacent said swash plate extending outwardly of said casing through said aperture in said swash plate, said cylinder block having an end face remote from said swash plate constituting a distribution end, ports leading inwardly toward the axis of rotation of said cylinder block from each of said piston accommodating bores to said distribution end so that said ports at said distribution end are clustered closely about the axi

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
US286317A 1962-10-09 1963-06-07 Axial piston hydraulic units Expired - Lifetime US3255673A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1177062A CH445298A (de) 1962-10-09 1962-10-09 Rückzugvorrichtung für hydraulische Axialkolbenmaschinen

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US3255673A true US3255673A (en) 1966-06-14

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CH (1) CH445298A (de)
GB (1) GB1006852A (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3611879A (en) * 1970-05-18 1971-10-12 Cessna Aircraft Co Axial piston device
US3739691A (en) * 1970-08-03 1973-06-19 W Bobier Fluid device
US3890882A (en) * 1970-08-03 1975-06-24 Wilfred S Bobier Fluid device having plastic housing and means for mounting a cylinder barrel
US4014250A (en) * 1971-04-05 1977-03-29 Robert Bosch G.M.B.H. Cylinder block positioning arrangement for a hydraulic axial piston machine
US4142450A (en) * 1976-01-13 1979-03-06 Thoma Jean U Axial piston rotary hydraulic machines
FR2532367A1 (fr) * 1982-08-24 1984-03-02 Bronzavia Sa Pompes a pistons axiaux solidaires de patins glissants sur une surface inclinee
US4896564A (en) * 1978-10-25 1990-01-30 Karl Eickmann Axial piston motor or pump with an arrangement to thrust the rotor against a shoulder of the shaft
US20040216601A1 (en) * 2003-02-03 2004-11-04 Kenji Matsumoto Rotating fluid machine
US11236736B2 (en) * 2019-09-27 2022-02-01 Honeywell International Inc. Axial piston pump with port plate having balance feed aperture relief feature

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3026765A1 (de) * 1980-07-15 1982-02-11 Linde Ag, 6200 Wiesbaden Axialkolbenpumpe fuer zwei foerderstroeme
FR2505398A1 (fr) * 1981-05-11 1982-11-12 Brille Maurice Embiellage pour une machine volumetrique a barillet

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525498A (en) * 1944-08-15 1950-10-10 Vickers Armstrongs Ltd Radial pump or hydraulic motor
US2577242A (en) * 1947-05-05 1951-12-04 Oilgear Co Axial type hydrodynamic machine
GB844496A (en) * 1957-05-31 1960-08-10 New York Air Brake Co Means for counteracting centrifugal force moments in rotary cylinder barrel engines
US3059432A (en) * 1962-05-08 1962-10-23 Thoma Hans Axial piston hydraulic units

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2525498A (en) * 1944-08-15 1950-10-10 Vickers Armstrongs Ltd Radial pump or hydraulic motor
US2577242A (en) * 1947-05-05 1951-12-04 Oilgear Co Axial type hydrodynamic machine
GB844496A (en) * 1957-05-31 1960-08-10 New York Air Brake Co Means for counteracting centrifugal force moments in rotary cylinder barrel engines
US3059432A (en) * 1962-05-08 1962-10-23 Thoma Hans Axial piston hydraulic units

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3611879A (en) * 1970-05-18 1971-10-12 Cessna Aircraft Co Axial piston device
US3739691A (en) * 1970-08-03 1973-06-19 W Bobier Fluid device
US3890882A (en) * 1970-08-03 1975-06-24 Wilfred S Bobier Fluid device having plastic housing and means for mounting a cylinder barrel
US4014250A (en) * 1971-04-05 1977-03-29 Robert Bosch G.M.B.H. Cylinder block positioning arrangement for a hydraulic axial piston machine
US4142450A (en) * 1976-01-13 1979-03-06 Thoma Jean U Axial piston rotary hydraulic machines
US4896564A (en) * 1978-10-25 1990-01-30 Karl Eickmann Axial piston motor or pump with an arrangement to thrust the rotor against a shoulder of the shaft
FR2532367A1 (fr) * 1982-08-24 1984-03-02 Bronzavia Sa Pompes a pistons axiaux solidaires de patins glissants sur une surface inclinee
US20040216601A1 (en) * 2003-02-03 2004-11-04 Kenji Matsumoto Rotating fluid machine
US11236736B2 (en) * 2019-09-27 2022-02-01 Honeywell International Inc. Axial piston pump with port plate having balance feed aperture relief feature

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Publication number Publication date
GB1006852A (en) 1965-10-06
CH445298A (de) 1967-10-15

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