US3520232A - Radial piston pump and motor device - Google Patents

Radial piston pump and motor device Download PDF

Info

Publication number
US3520232A
US3520232A US751801A US3520232DA US3520232A US 3520232 A US3520232 A US 3520232A US 751801 A US751801 A US 751801A US 3520232D A US3520232D A US 3520232DA US 3520232 A US3520232 A US 3520232A
Authority
US
United States
Prior art keywords
piston
rings
pistons
segments
reaction ring
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
US751801A
Other languages
English (en)
Inventor
Jaromir Tobias
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Application granted granted Critical
Publication of US3520232A publication Critical patent/US3520232A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • F01B13/00—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion
    • F01B13/04—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion with more than one cylinder
    • F01B13/06—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion with more than one cylinder in star arrangement
    • F01B13/061—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion with more than one cylinder in star 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
    • 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
    • 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
    • F01B1/0668—Supporting and guiding means for the piston
    • 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
    • F01B1/0675—Controlling
    • F01B1/0686—Controlling by changing the effective piston stroke
    • F01B1/0689—Controlling by changing the effective piston stroke by changing the excentricity of one element relative to another element
    • 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
    • F01B13/00—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion
    • F01B13/04—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion with more than one cylinder
    • F01B13/06—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion with more than one cylinder in star arrangement
    • F01B13/061—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion with more than one cylinder in star arrangement the connection of the pistons with the actuated or actuating element being at the outer ends of the cylinders
    • F01B13/062—Reciprocating-piston machines or engines with rotating cylinders in order to obtain the reciprocating-piston motion with more than one cylinder in star arrangement the connection of the pistons with the actuated or actuating element being at the outer ends of the cylinders cylinder block and actuating or actuated cam both rotating

Definitions

  • a radial piston pump or motor including a pintle shaft, a cylinder block rotatable about the pintle shaft, and a reaction ring chassis shiftable transversely of the pintle shaft, a ring assembly rotatably mounted on the chassis, and a series of piston-reaction ring segments carried by said ring assembly to be movable relative to each other and the ring assembly, said segments including piston members extending radially into the bores of the block, the piston members including parti-spherical piston heads to permit a relative tilting of the pistons within the bores.
  • This invention is in the field of radial piston pumps and motors.
  • Radial piston pumps and motors typically comprise a pintle shaft, a cylinder block rotatable about the shaft, including a series of radially directed bores, the bores being connected to the discharge areas of the pintle shaft during rotation by radially directed fluid passages.
  • Pistons are mounted within the bores for radial shifting movement, the distal ends of the pistons being engaged against a surrounding reaction ring, the axis of which reaction ring may be displaced from the axis of rotation of the block.
  • the outer ends of the pistons in certain constructions, are not directly engaged by the reaction ring, the pistons in such instances being provided with pivotal connections to piston shoes, which shoes, in turn, slide against and engage the surrounding reaction ring.
  • the reaction ring rotates with the block and induces an inward and outward movement of the pistons.
  • the device is used as a motor
  • fluid under pressure is introduced to the supply area of the pintle shaft and is taken from the discharge area, inducing rotation of the block.
  • the block is rotated, causing fluid under pressure to be expressed through the discharge area of the pintle shaft.
  • the piston heads are cylindrical, the length of the cylindrical piston portions in slidable engagement with the cylinder walls varying with the requirements of the particular pump or motor.
  • elongated cylindrical pistons have been employed but the use of these devices involves other drawbacks. Specifically, where an elongated piston is employed, lubrication throughout the length of the piston becomes a problem since normal leakage about the periphery of the piston is effective to lubricate a portion only of the length of the piston. Similarly, the use of an elongated piston will obviously increase the over-all size of the radial piston device of a given displacement.
  • Lubrication in this area is often provided by controlled leakages through passages in the pistons and and piston slippers, which introduce a film or oil between the piston slippers and the reaction ring. While the losses which inhere in utilizing such controlled lubrication are individually relatively small, they are collectively significant since elficiency loss is measured as a multiple of the losses of each component of the system. -In many instances, such lubrication is effected through minute passages formed in the length of the pistons and piston slippers, which passages communicate with fluid in the cylinder proper.
  • a radial piston pump or motor comprising a pintle shaft having a fluid supply and discharge areas, a cylinder block having radially directed cylinder bores, passages communicating the bores with the supply and discharge areas sequentially during rotation, a reaction ring chassis shiftable transversely of the pintle shaft, including a ring assembly rotatable relative to the chassis, the device being particularly characterized by a series of piston-reaction ring segments movable relative to each other and mounted on the ring for angular or arcuate movement about the axis of the rings, the segments including piston members aflixed thereto and terminating in parti-spherical piston heads disposed in sealing relation of the cylinder bores.
  • the segments may be individually mounted and dismounted, and may move toward and away from each other in a plane perpendicular to the axis of the pintle shaft in the course of rotation, while at all times maintaining the pistons perpendicular to the axis of rotation of the rings, whereby the force vectors of the pistons are at all times aligned for optimum efficiency.
  • a further object of the invention is the provision of a device of the class described which may be readily manufactured and assembled and wherein replacement of individual piston-reaction ring segments may be effected without disassembly of the entire device.
  • a further object of the invention is the provision of a device of the class described wherein forces exerted by or against the pistons are at all times aligned in a direction to operate with utmost efficiency.
  • Still a further object of the invention is the elimination of the difiicult lubrication problems resulting from the requirement of conducting lubricant under high pressure to the area between the piston head or piston slipper and the reaction ring, a position which, in all prior known devices of this sort, is a considerable radial distance from the pintle shaft.
  • FIG. 1 is a vertical sectional view through a hydraulic pump or motor in accordance with the invention, certain details of the apparatus being depicted in simplified form to facilitate an understanding of the invention;
  • FIG. 2 is a discontinuous section taken on the line 2-2 of FIG. 1;
  • FIG. 3 is a section taken on the line 33 of FIG. 2.
  • a pintle shaft having fluid input and output conduits 11, 12, which may be connected either to a source of fluid under pressure and a reservoir, where the device is used as a motor, or to a hydraulic motor, where the device is used as a pump.
  • the pintle shaft is provided with laterally open discharge and supply areas 13, 14, separated by diametrically opposed lands 15, 16 in a well known manner.
  • the pintle shaft in the illustrated embodiment is provided with a continuous cylindrical portion 17 at its innermost end for defining a seal.
  • a cylinder block assembly 18 is mounted for rotation on the pintle shaft.
  • the block 18 is disclosed to comprise a hollow shell, for purposes of lightness, it being recognized that the conventional solid casting having radially directed cylinder bores may be substituted for the shell, where lightness is not a consideration.
  • the block 18 is provided with seal areas 19, 20 engaged against solid peripheral areas of the pintle shaft axially displaced from the fluid supply-discharge areas, which seal areas may incorporate any usual form of rotary seal 20.
  • the block includes an end Wall 21 connected to an output or input shaft 22, as by a pair of machine screws 23 (one only being illustrated) displaced from the center of the shaft.
  • a series of radially directed cylinder bores 24 (seven in the illustrated embodiment), are formed in the block.
  • fluid in the discharge and supply areas 13 or 14 is communicated to the bores 24 through flow passages 25 extending between the cylindrical bores and the supply and discharge areas of the pintle shaft.
  • the supply passages 25 are configurated in the manner set forth in said patent, i.e. they are elongated in the direction of the axis of the pintle shaft and foreshortened in the angular direction at the pintle shaft, and grow progressively shorter and wider and merge smoothly with the cylinder bores 4 at the area radially outwardly spaced from the pintle shaft.
  • a reaction ring chassis 26 is supported on the frame of the device (not shown) in a manner to permit lateral movement of the chassis with respect to the pintle shaft within the limits permitted by the eccentricity slots 27, 28 formed at the opposed ends of the chassis. It will be understood that lateral movement may be applied to the chassis by any suitable manual or automatic means.
  • the apparatus for imparting lateral movement is depicted as an adjustment lever 29 mounted on a fixed fulcrum pin 30.
  • the lower end of the lever 29 carries a bifurcated yoke 31 which surrounds drive pin 32 on the chassis, it being understood that pivotal movement of the lever about the pin 30 will cause a side-to-side adjustment of the chassis.
  • the chassis is provided with a spaced pair of rings 33, 34, separated from the circular periphery of walls 35, 36 forming the chassis 26 by roller bearing assemblies 37, 38.
  • pistonreaction ring segments 39 which are generally U-shaped in vertical section (see FIG. 2), the U-shaped elements being defined by generally trapezoidal side legs 40, 41, the outer ends of which legs are linked by arcuate bridging elements 42.
  • the legs 40, 41, at their innermost radial ends 43, are arcuate, to conform to the radius of curvature of the outer periphery of the rings 33 and 34.
  • the ends 43 are enlarged in the direction of the axis of the pintle shaft in comparison to the thickness of the major portion of the legs 40, 41, defining radially outwardly directed arcuate shoulders 44, 45.
  • the legs of the piston-reaction ring segments are maintained in juxtaposition to the outer periphery of the rings 33, 34 by inner and outer arcuate attachment fixtures 46, 47.
  • the attachment fixtures are generally L-shaped in section, including inwardly directed, arcuate overlap shoulders 48, 49, respectively, disposed in mating complemental relation to the outwardly directed shoulders 44, 45, respectively, defined by the enlargement portion 43 at the inner ends of the legs.
  • the radii of curvature of the inturned portions 48, 49 and the shoulders 44, 45 are the same, so as to provide a smooth mating alignment to these parts.
  • the legs 40, 41 of the piston-reaction ring segments are secured to the rings 33, 34 against relative radial outward movement by cross pins 50 which pass through aligned apertures in the inner and outer fixtures 46, 47 and in the rings 33, 34.
  • the cross pins 50 have thus an enlarged head 51 lying against the inner and outer segments 46, 47, the shank 52 of the pins extending through the aligned apertures in the inner segment 46, ring 34, outer segment 47, and a washer 53.
  • Cotter pins 54 or like securing members may be passed through apertures formed in the outer ends of the pins 50 to maintain the pins in the desired position.
  • at least two pin members are employed to hold each pair of fixtures 46, 47.
  • the segments 39 may be moved angularly relatively to the rings by the above noted arrangement so that adjacent piston-reaction ring segments 39 are enabled to approach and retreat from each other in the course of rotary movement, such approach and retreat travel being confined with a plane perpendicular to the axis of rotation of the rings 33, 34.
  • leg portions of all of the piston-reaction ring segments are secured to the rings in a similar fashion.
  • one or more roller bearmgs may be interposed between the piston-reaction ring segments and the rings 33, 34, rather than relying upon the arcuate mating bearing surfaces previously described.
  • the rings may be provided with outwardly directed flanges and the reaction ring segments may be provided with roller bearing components which engage against the inwardly directed surfaces of the flanges, the above structure being mentioned by way of example only.
  • piston rods 55 From the bridging portions 42 of the piston-reaction ring segments there extend radially inwardly directed tubular piston rods 55. It will be understood that while the piston rods 55 have been shown as integral with the bridging portion 42, it is altogether feasible to provide a replaceable connection wherein the rod is removably secured to the bridging element.
  • the radial innermost ends of the rods 55 are provided with piston heads 56, the peripheries of which heads are parti-spherical in section.
  • the parti-spherical plston heads permit relative tilting movement of the pistons within the bores 24, the parti-spherical nature of the heads assuring a sealed condition of the bores throughout all tilted positions.
  • the shaft 22 is connected to a source of rotative power, thus to drive the cylinder block 18 about the pintle shaft.
  • the rotation of the block will cause a concomitant rotation of the rings 33, 34 and the reaction ring segments 39.
  • the adjustment lever 29 is arranged so that the axis of rotation of the rings 33, 34 is in alignment with the axis of the pintle shaft, no inward or outward movement of the pistons relative to the cylinder bores will be experienced and no pumping action will take place.
  • the segments 39 will be equally spaced from each other throughout the entire rotation of the device.
  • the amount of eccentricity permitted should be calculated to prevent interference between the sides of the piston rods 55- and the bores 24 of the block, it being appreciated that the greater the eccentricity, the greater the separation and approach of the piston-reaction ring segments and, hence, the greater the tilting of the pistons in the cylinders.
  • the unit may be readily assembled and disassembled for replacement of an individual reaction ring-piston segment, for instance, without the necessity for disassembling the remaining segments.
  • the over-all diameter of the unit will be reduced by a considerable factor and the unit will be lighter in weight.
  • lubrication is facilitated by avoiding the necessity of transporting lubricating fluid under pressure into space between the outer-most ends of the pistons and the reaction rings, as is required in all prior known radial piston devices.
  • the piston axis must always be precisely aligned with the center of the rotating rings 33, 34, the force vector alfecting the pistons will always be aligned and exerted in the most efficient manner possible.
  • the axes of the pistons are radially directed with respect to the axis of the cylinder block. This requires that the end of the piston or the piston shoe engage against the reactron rmg at an angle with respect to the reaction ring, rather than perpendicular to the engaged portions of the reaction ring. Such angular relation of the parts induces a tilting moment in the pistons, with the result that a purely radial force is not applied.
  • the tilting moment results in increased wear on the sides of the pistons and cylinder bores as well as at the area of engagement between the piston heads and the reaction ring.
  • piston-reaction rmg segments are shown as essentially integral components comprising integral leg portions 40 and 41 and bridging portion 42, it will be evident that these elements may be comprised of separate parts, subsequently integrated by machine screws, cross pins, etc.
  • a radial piston pump or motor comprising a pintle shaft having fluid supply and discharge areas, a cylinder block rotatably mounted on said shaft having radially directed cylinder bores and passages connecting said bores with said areas, and a chassis surrounding said pintle shaft and movable transversely with respect thereto, the improvement which comprises a spaced pair of rings at opposite sides of said block mounted on said chassis for rotation about a common axis, a series of generally U-shaped piston assemblies, in number corresponding to the number of said bores, mounted on said rings, each said assembly comprising a spaced pair of legs, a leg of each said assembly being movably connected to a dif ferent one of said rings for sliding movement relative to said rings in an arcuate path concentric with the axis of rotation of said rings, a bridging member joining the ends of said legs remote from said rings spaced radially outwardly of said block and a piston member rigidly fixed to and extending radially from said bridging member into a
  • each said leg portion includes an outwardly directed arcuate surface concentric with the axis of said rings, said fastener means comprising arcuate segments removably secured to said rings and having inwardly directed arcuate bearing surfaces in outwardly lapping, slidable engagement with the outwardly directed arcuate surfaces of said leg portions.
  • a radial piston pump or motor comprising a pintle shaft having fluid supply and discharge areas, a cylinder block rotatably mounted on said shaft and having radially directed cylinder bores and passages connecting said bores with said areas, a ring chassis surrounding said pintle shaft and movable transversely with respect thereto, the improvement which comprises a bearing ring assembly rotatably mounted on and surrounding said chassis, said ring assembly being rotatable relative to said chassis about an axis parallel with the axis of said shaft, a plurality of reaction ring segments, mounting means connecting said segments to said ring assembly to permit relative sliding movement of said segments and ring assembly in an arcuate path concentric with the axis of rotation of said ring assembly, while limiting relative radial movement of said parts, a piston member fixed to each of said segments against angular movement and extending radially inwardly toward the axis of said ring, the inner ends of said piston members being defined by parti-spherical piston heads disposed in sealing relation of
  • said mounting means includes a segment removably secured to said ring assembly and having an inwardly directed arcuate surface in outward lapping engagement of a complemental, outwardly directed bearing surface formed on said reaction ring segment.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Hydraulic Motors (AREA)
US751801A 1968-08-12 1968-08-12 Radial piston pump and motor device Expired - Lifetime US3520232A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US75180168A 1968-08-12 1968-08-12

Publications (1)

Publication Number Publication Date
US3520232A true US3520232A (en) 1970-07-14

Family

ID=25023530

Family Applications (1)

Application Number Title Priority Date Filing Date
US751801A Expired - Lifetime US3520232A (en) 1968-08-12 1968-08-12 Radial piston pump and motor device

Country Status (10)

Country Link
US (1) US3520232A (fr)
AT (1) AT296031B (fr)
BE (1) BE727835A (fr)
CH (1) CH492127A (fr)
DE (1) DE1900366A1 (fr)
FR (1) FR1600600A (fr)
GB (1) GB1208648A (fr)
IL (1) IL31184A (fr)
NL (1) NL6901116A (fr)
SE (1) SE349100B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3955477A (en) * 1973-11-27 1976-05-11 Sulzer Brothers Limited Hydrostatic piston machine having a guide for laterally guiding a cylinder block pintle

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1243494A (en) * 1917-03-19 1917-10-16 Harry C Dunning Steam-engine.
GB232373A (en) * 1924-02-19 1925-04-23 Hans Thoma Improvements in revolving-cylinder pumps or motors for hydraulic transmission of power
US2510247A (en) * 1942-05-19 1950-06-06 Joseph S Parenti Apparatus for compressing fluids
US3107622A (en) * 1960-11-14 1963-10-22 Suden Adolph F Graf Von Combined hydraulic and pneumatic pump and motor unit for simultaneous air, vacuum and fluid circulation
US3274946A (en) * 1964-04-13 1966-09-27 Edward E Simmons Pump
US3345916A (en) * 1965-11-17 1967-10-10 Tobias Jaromir High efficiency hydraulic apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1243494A (en) * 1917-03-19 1917-10-16 Harry C Dunning Steam-engine.
GB232373A (en) * 1924-02-19 1925-04-23 Hans Thoma Improvements in revolving-cylinder pumps or motors for hydraulic transmission of power
US2510247A (en) * 1942-05-19 1950-06-06 Joseph S Parenti Apparatus for compressing fluids
US3107622A (en) * 1960-11-14 1963-10-22 Suden Adolph F Graf Von Combined hydraulic and pneumatic pump and motor unit for simultaneous air, vacuum and fluid circulation
US3274946A (en) * 1964-04-13 1966-09-27 Edward E Simmons Pump
US3345916A (en) * 1965-11-17 1967-10-10 Tobias Jaromir High efficiency hydraulic apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3955477A (en) * 1973-11-27 1976-05-11 Sulzer Brothers Limited Hydrostatic piston machine having a guide for laterally guiding a cylinder block pintle

Also Published As

Publication number Publication date
IL31184A0 (en) 1969-01-29
SE349100B (fr) 1972-09-18
FR1600600A (fr) 1970-07-27
IL31184A (en) 1972-12-29
NL6901116A (fr) 1970-02-16
GB1208648A (en) 1970-10-14
DE1900366A1 (de) 1970-04-16
AT296031B (de) 1972-01-25
CH492127A (fr) 1970-06-15
BE727835A (fr) 1969-07-16

Similar Documents

Publication Publication Date Title
RU2078942C1 (ru) Сборочный узел двигателя или насоса
US2335284A (en) Rotary fluid pressure device
US3107955A (en) Bearing
JPH01200068A (ja) アキシャルピストンポンプ
US1945391A (en) Pump
US2205913A (en) Pump
US3186352A (en) Variable displacement piston pump
US2421846A (en) Fluid pressure engine
US3067694A (en) Piston pump
US2426100A (en) Hydraulic pump or motor of the radial cylinder type
US3520232A (en) Radial piston pump and motor device
US2709408A (en) Variable displacement radial piston pump
US2246074A (en) Motor
US4426914A (en) Axial piston pump
US3739691A (en) Fluid device
US3277834A (en) Rotary radial piston machine with enlarged piston stroke
US2674196A (en) Piston assembly for axial type hydrodynamic machines
US3899957A (en) Radial piston fluid translating device with cylinder positioning means
JPS6235082A (ja) 回転斜板型アキシヤルピストンポンプ・モ−タ
US1924124A (en) Pump
US3828657A (en) Piston for swash plate pump
US2381741A (en) Pump or motor unit
US2373449A (en) Pump
US2041172A (en) Pump or motor
US2248738A (en) Hydraulic pump or motor