Abstract: For an assembly of two bodies wherein one of the bodies has a part-ball portion and the other has a part-ball formed hollow seat of complementary surface, a slot is provided in the body with the hollow portion and the ball formed portion of the other body is mounted into the hollow portion, while a spring washer presses the bodies together when a snap ring having an extension engaging into the slot and being kept in a ring groove is inserted into the hollow portion. The body with the ball formed portion has retaining faces which are engaged by the washer and the washer also has an extension to enter into the slot, whereby the assembly assures, that one of the bodies can pivot relatively to the other body, but that the bodies are prevented from rotational movements relatively to each other.

Abstract: A hydrostatic transmission having a pump and a motor of the radial piston type with each cylinder slipper bearing rotatably supported by a hybrid or combination hydrostatic and hydrodynamic bearing on an internal bearing. The hydrostatic bearing component has a restricted port connecting hydrostatic pressure fluid from the cylinder to supply a distribution recess in the slipper bearing surface for hydrostatic pressure feed of the fluid film providing hydrostatic balancing pressure gradient between the slipper and internal bearing to balance a high percentage of the hydrostatic pressure load and to meet flow requirements for low speed operation.

Abstract: The axial piston machine, such as an engine or a pump, comprises a radial hydrostatic bearing for the drive shaft in the form of an oil gap between a conical shaft portion and a corresponding conical boring in a bearing block. The gap has a plurality of bearing pockets normally supplied with high-pressure oil via throttling means communicating with the high-pressure oil. An auxiliary axial hydrostatic bearing in the form of a bearing gap defined between the face of the bearing block near the tapering end of the bearing body and a radial extension of the drive shaft is supplied with an auxiliary low-pressure oil having an approximately constant pressure. A self-adjustable pressure chamber is provided in a plane parallel to the axial hydrostatic bearing gap and is defined by a collar supported on the drive shaft opposite the first radial extension and communicating with the axial bearing gap via a conduit.

Abstract: A piston for a hydrostatic piston machine, especially an axial-piston pump or motor in which the piston is formed with a ball head riding in a slide shoe which is supported by a fluid-pressure cushion against a countersurface, e.g. a swashplate. The piston is formed with a central passage which communicates with a bore in the ball head, this bore being provided with a throttle to prevent the fluid medium from being forced at an excessive rate into the fluid-pressure cushion and thereby lift the shoe from the countersurface. According to the invention, the end of the piston remote from the ball head is provided with a gap filter of large area and narrow gap width to prevent large particles from entering and blocking the passage and the throttle.

Abstract: Piston shoes in radial piston devices of the prior art were provided with balancing fluid pressure pockets of circular configuration or of elongation normal to the movement direction of the piston shoes. Piston shoes had to provide the space for said pockets and thereby extended over the diameter of the piston. That resulted in deformation of the piston shoe and in friction in areas that cannot be lubricated between the piston shoe outer face and the piston actuator guide face. The invention provides a pair of balancing pockets normal to that of the prior art and extended in the movement direction of the piston shoes. Piston shoes are therefore short in the direction of the pivot axis, deformations are prevented and the areas that cannot be lubricated are reduced to a minimum or removed. The piston shoe becomes thereby able to operate under higher pressures, increased relative speeds and with better efficiency at assured perfect lubrication between neighboring faces.

Abstract: A radial-piston machine has a rotor formed with a plurality of each a piston carrying radial cylinders. Each such piston is formed on its radially outer end with a part-spherical seat and a part-spherical portion of a respective piston shoe that rides on an eccentric cam in the housing is engageable in each seat. Each such piston shoe can move radially into and out of engagement with the respective piston. A pair of end members axially flank the piston shoes with play so that these shoes may also move axially relative to the motor. The piston-engaging portions of the shoes are always engaged radially in said cylinders. The cylinders may have outer portions with a cross-slot extending parallel to the axis of the rotor through said cylinders.

Abstract: A hollow piston for a hydrostatic piston machine and especially for a swash-plate-type axial-piston pump or motor, comprises a hollow outer cylinder member which is formed at one end with a ball head and at the other end with a cover. Extending centrally through this hollow piston is a central post having its opposite ends secured to or engaging the opposite ends of the outer piston member and formed with a central bore communicating between a passage in the cover and a passage in the ball head. At least one of these ends of the central post is juxtaposed with a respective end of the piston and the juxtaposed ends are formed with a conical surface and an edge engaging this surface to seal the post to the outer member.

Abstract: A static pressure thrust bearing includes a shoe member or a thrust axis provided with a static pressure pocket and a land for sealing the static pressure within the pocket, and a swash plate on a sliding surface provided with a slide surface upon which the shoe member is slidable. Lubricating oil flows through the shoe member and between the slide surface and the land surface, and each of the land and slide surfaces has a plurality of very small recesses so as to receive small particulates which may be within the lubricating oil. The difference of the static pressure occurring between the land surface and the slide surface alternately moves the small particulates originally disposed within one of the recesses thereof, into the other recesses as a result of the sliding movement of the shoe member whereby the small particulates are removed from the bearing by means of the lubricating oil.

Abstract: A variable delivery hydraulic equipment is designed to be operated as a pump or a motor and includes a cylinder block having a plurality of cylinder bores on the same circumference thereof and a plurality of plunger assemblies each disposed within the cylinder bore. The plunger assembly has a pair of plungers oppositely disposed within the cylinder bore so as to define a chamber therebetween and slidably movable within the cylinder bore. A pair of cams are disposed in contact with opposite plungers with the cylinder block disposed therebetween. The cams each have a cam surface for imparting a plurality of reciprocatory movements in one cycle to the opposite plunger in a manner that the moving velocities of the opposite plungers are different from each other in all phase position. The cam surfaces are formed to have sine curves each having two crests and a different stroke. In consequence, the volume of the chamber between the opposite plungers is always varied.

Abstract: A rotary machine usable as a pump, compressor, turbine or motor, for example. Rotating piston cylinders have radially movable pistons therein and the cylinders are mounted within a control ring and a housing. The control ring is tangentially pivoted within the housing to vary the volume flow through the machine and the torque application transmitted by a shaft, as well as the direction of flow through the machine. Pressure fluid operated balancing pistons are used to counter the axial thrust placed on the rotor by liquids applied to the rotor, regardless of the direction of flow through the machine.

Abstract: A fluid pressure unit with a cylinder block is provided with radial bores of rectangular cross section. Pistons are disposed in the bores, each of the pistons being provided with a piston cap which is subjected periodically to pressure of a medium and with a roller resting against the piston cap. A cam is provided around the cylinder block, upon which the respective rollers rest. Each roller defines a variable throttle space with a first side wall of a respective one of the radial bores, which wall is vertical with respect to the rotational direction. The piston cap forms a sealing point with at least a second of two side walls.

Abstract: The hydraulic motor has a shaft rotatably mounted in a housing and mounting an eccentric to which is journaled an annular ring. A plurality of radial pistons are adapted for sliding movement within spherical members having cylindrical bores for receiving the radial pistons. Each of the spherical members is adapted for oscillating movement between an annular abutment and a spring-mounted annular ring-type valve seat.The ring acts as a distributor sleeve or and as a conduit for fluid passing to and from the cylinders and a planar distributor.The hydraulic motor can be used either as a pump or a motor at low or high speeds and under high pressures and is reversible.

Abstract: A swash plate pump or motor is provided having a swivel plate surrounding the slippers and a positive hold down ring connected to the swash plate and bearing on said swivel plate to maintain it at a fixed distance from the slipper plate, said hold down ring having a series of successive controlled wedge angles on the face bearing on the swivel plate and oil feed means connected to each wedge angle whereby a hydrodynamic force is created holding the swivel plate and hold down ring apart.

Abstract: A variable delivery hydraulic equipment is designed to be operated as a pump or a motor and includes a cylinder block having a plurality of cylinder bores on the same circumference thereof and a plurality of plunger assemblies each disposed within the cylinder bore. The plunger assembly has a pair of plungers oppositely disposed within the cylinder bore so as to define a chamber therebetween and slidably movable within the cylinder bore. A pair of cams are disposed in contact with opposite plungers with the cylinder block disposed therebetween. The cams each have a cam surface for imparting a plurality of reciprocatory movements in one cycle to the opposite plunger in a manner that the moving velocities of the opposite plungers are different from each other in all phase position. The cam surfaces are formed to have sine curves each having two crests and a different stroke. In consequence, the volume of the chamber between the opposite plungers is always varied.

Abstract: This invention relates to fluid handling devices where fluid flows through a rotary body with thereto associated pistons and piston shoes for working as a motor, pump, engine or transmission, and wherein the improvement consists in the provision of recesses in the rotary body for the reception of parts of the piston shoes; in the provision of securing walls on the rotary body for preventing excessive axial displacement of the piston shoes, and in the provision of a backwards shoulder on the pistons of the device for preventing excessive backwards tilting of the piston shoes of the device.

Abstract: A piston for a hydrostatic machine comprises a cam follower ball in a seating in a piston body. An aperture through the piston body provides access for working fluid to reach the seating to give lubrication and hydrostatic support. A low friction insert of synthetic plastics material in the seating provides a bearing surface for the ball. The insert is retained in the piston body by a lip which prevents or inhibits extrusion of the plastics material under working load pressure.

Abstract: A fluid-operated radial piston machine has two rotors rotating at the same angular velocity, with a working rotor being formed with substantially radial working chambers having working fluid flowing therethrough and having pistons reciprocable in the working chambers. The other rotor is a bearing rotor. Connections members are interposed between the pistons and the bearings rotor and are pivotally seated in the bearing rotor as well as in the respective pistons. The bearing rotor has axially extending incompletely circular grooves receiving cylindrical heads on the connection members, and the inner ends of the connection members are formed with cylindrical or spherical bearing surfaces seating in the pistons. Fluid pressure chambers are formed on the various bearing surfaces to receive fluid under pressure to reduce friction.

Abstract: In a piston machine of the type having a housing, a reciprocable piston in the housing and provided with an axial end portion and a piston-reciprocating element having a glide surface located opposite and movable with reference to the end portion for effecting the reciprocation of the piston, the invention provides for a glide shoe which is articulately connected to the end portion of the piston and which has a glide face in gliding contact with the glide surface of the piston-reciprocating element. The glide face has a recess which communicates via a passage with a source of pressure fluid, a sealing rim of substantially constant width surrounding the recess, and a plurality of face portions which are located outwardly of the sealing rim and configurated so that hydrodynamic pressure fields develop between the face portions and the respectively juxtaposed surface portions of the glide surface.

Abstract: In a pump or motor assembly having telescoped slidably relatively rotative surfaces whereby one of the members supports the other member for relative rotation and one of the members has passage means for hydraulic pressure fluid. Hydraulic bearing means between the surfaces in communication with the pressure fluid passage have distribution of hydraulic pressure fluid to the bearing means controlled by valve means to improve efficiency of the hydraulic bearing means to counteract off-center forces. In a preferred arrangement the bearing means comprise circumferentially spaced pockets in one of the relatively rotative surfaces, and the valve means control distribution of hydraulic pressure fluid to the pockets by modulating lowered pressure in any of the pockets.

Abstract: A fluid pump or motor is disclosed having a housing with a central opening in one side thereof and containing fluid inlet and outlet ports in which one portion of the housing includes a slipper bearing formed in the end opposite the central opening where the axes of the slipper bearing and central opening are in eccentric alignment with a shaft rotatably supported within the central opening of the housing where piston means for operating in a cylinder has the end nearest the center of the shaft with a segment of circular cross-section slot formed therein, the axis of which is parallel to the axis of the shaft with a slipper of substantially circular cross-section nested in the slot of each piston with the slipper extending beyond the walls of each piston in reduced radial configuration and working with a rotor having a plurality of radially arranged cylinders, each cylinder having a port at the outer end thereof and having the walls of each cylinder nearest the center of the rotor containing a dome shaped voi

Abstract: A hydraulic pump of the axial piston type comprising check valves each of which is adapted to open and allow the associated cylinder to discharge fluid when the pressure inside the cylinder has been raised above the discharge pressure of the pump by the piston on its compression stroke, passage means for communicating each of the cylinders with the low-pressure system including a pump suction pipe or drain tank during the period in which the piston on the compression stroke moves from a point at least short of the top dead center to a point past the center and where the cylinder communicates with the suction port, and pressure-reducing means disposed in the passage means.

Abstract: A radial type hydraulic pump motor according to the present invention has pistons, each of which is formed at its head portion with a concave or convex spherical surface. Engaged spherically with said spherical surface head portion is a piston shoe whose outer planar portion is slidably engaged with the inner planar portion of a crescent-shaped segment arcuately engaged with the inner peripheral surface of a drum case. Said piston shoe is formed at its outer planar portion with a hydraulic recess equal to the effective pressure receiving area of piston in area. Said recess is maintained in communication with a cylinder chamber. Accordingly, said spherically engaging portion and arcuately engaging portion make little sliding movements and only the outer planar portion of piston shoe and the inner planar portion of segment mutually make sliding movement under little contact pressure, thereby causing little wear to said engaging portion and sliding portion.

Abstract: A piston and slipper arrangement for a hydraulic pump or motor includes a tortuous fluid flow passage through the piston to a fluid pressure recess in the thrust face of the slipper at the opposite end of the piston. The fluid passage is formed by a plurality of spaced, cylindrical pockets interconnected by restricted flow channels which tangentially join the pockets.

Abstract: The invention provides a hollow core filled piston including core retaining means for mechanically interlocking and retaining a core of filler material within the piston against angular and axial displacement. The piston includes a hollow skirt portion defining a stepped-bore cavity, and retaining means for retaining a core of filler material within the cavity comprising a plurality of annular projections formed from the shoulder between the stepped bores. The invention further provides a tool for cutting and displacing segments of the shoulder to form the annular projections.

Abstract: A piston shoe for fluid pressure pump motors of the piston type is substantially disc-shaped and includes a concave portion provided upon one end face thereof for seating the convex portion of a piston rod associated with the piston and cylinder assemblies of the pump motor, while the other end face thereof is substantially flat for contacting the sliding surface of a swash plate. A holder or retainer is also provided in association with the shoe for retaining the piston rod within the concave seat, such retainer being secured to the shoe by biasing means, or alternatively by being pressed or crimped thereon.

Abstract: This invention relates to fluid handling devices where fluid flows through a rotary body with thereto associated pistons and piston shoes for working as a motor, pump, engine or transmission, and wherein the improvement consists in the provision of recesses in the rotary body for the reception of parts of the piston shoes; in the provision of securing walls on the rotary body for preventing excessive axial displacement of the piston shoes, and in the provision of a backwards shoulder on the pistons of the device for preventing excessive backwards tilting of the piston shoes of the device.

Abstract: A hydraulic pump or motor having: oil grooves in the internal partial-spherical surface of a piston for introducing pressure oil between said internal partial-spherical surface and a ball; oil grooves in the peripheral surface of the large diameter portion of said piston for introducing pressure oil between the outer peripheral surface of the large diameter portion of said piston and a cylinder; small diameter passages provided through said piston and extending from the upper end of said piston to said oil grooves, while communicating with an oil chamber for said piston; and necked or throttle portions provided in said small diameter passages, respectively, to thereby give rise to pressure drops for oil which is passing through said small diameter passages.

Abstract: A radial piston machine has a rotor which turns within the confines of a surrounding annular control face and is provided with substantially radial cylinder bores each accommodating a radially slidable piston having an outer end provided with a piston shoe formed with guide portions projecting circumferentially of the rotor beyond the associated piston and having contact faces which are in sliding engagement with the control face. Each of the contact faces has a hydrostatic bearing constituted by a depression surrounded by a sealing land, and recesses are formed in the respective contact faces outwardly spaced from the sealing lands, so as to separate the latter from outwardly adjacent portions of the contact faces.

Abstract: In a piston machine of the type having a housing, a reciprocable piston in the housing and provided with an axial end portion and a piston-reciprocating element having a glide surface located opposite and movable with reference to the end portion for effecting the reciprocation of the piston, the invention provides for a glide shoe which is articulately connected to the end portion of the piston and which has a glide face in gliding contact with the glide surface of the piston-reciprocating element. The glide face has a recess which communicates via a passage with a source of pressure fluid, a sealing rim of substantially constant width surrounding the recess, and a plurality of face portions which are located outwardly of the sealing rim and configurated so that hydrodynamic pressure fields develop between the face portions and the respectively juxtaposed surface portions of the glide surface.

Abstract: The bearing surface of each piston is provided with hydrostatic pressure medium during operation to maintain the axis of the piston perpendicular to the guide surface. The pressure medium is supplied through throttle passages which terminate in feed openings at the corners or at uniformly distributed points remote from the piston axis. Cooperating guide ledges are also provided on each foot and on the guide member to prevent the piston bearing surfaces from falling away from their respective guide surfaces of the guide member.

Abstract: In a hydraulic motor or pump comprising a casing, a shaft, means journalling said shaft in said casing, an eccentric on said shaft, a bearing block within said casing and about said eccentric and having a bore permitting relative rotation between said bearing block and said eccentric, a plurality of hydraulic cylinders formed and grouped in said bearing block radially about said eccentric in a common plane normal to the axis of said shaft, a plunger slidable in each of said cylinders, said plunger having an outer end face, flat faces of abutments formed in said casing at its internal surface for engagement with said outer end faces of said plungers, respectively, means urging said plunger in the direction of said face abutment of said casing during the operation of said motor or pump, and said bearing block having a port communicating between its bore and the interior of each of said cylinder interior, whereby pressure liquid is admitted to the cylinders in turn one after another during the operation of said

Abstract: The invention refers to an axial-piston pump or motor, having a piston which defines, with a cylinder, a chamber. A first end of the piston bears against a plate by means of a hydrostatic shoe having a cavity in the bearing face, a duct connecting the chamber to that cavity and being furnished with a constriction.The piston has a recess which is arranged in the cylindrical portion of its second end remote from the first end, the constriction being constituted by the clearance lying between at least one collar portion of the piston which separates the recess from the chamber and the cylinder. A second recess is provided in the piston, the constriction being located between the first and second recesses.The invention is applicable to the execution of a pump having high operational characteristics, particularly as far as concerns pressure.

Abstract: Radial piston pump or motor has within its housing a stationary pintle valve, an external shaft connected to a rotating spider of which are mounted pressure balanced pivotal cylinders. Rigid piston - shoe assemblies engage the cylinders and ride on a cylindrical raceway the eccentricity of which is adjustable for stroke. Balanced annular sealing is provided between the pivotal cylinders and arcuately surfaced pockets therefor in the rotating spider/rotor.

Abstract: An axial piston machine has a cylinder barrel mounted on a shaft and rotatable with respect to a portion of the casing. Between the cylinder block and the casing portion is a disc. The side of the disc adjacent the casing portion is concave and abutting casing portion is correspondingly convex. The disc is restrained against rotation and forms part of the valving means for the cylinder barrel. In one embodiment the casing and shaft are in two articulated sections. The shaft sections lie in a common plane and are pivotable with respect to each other about a point and the casing sections are pivotable about an axis normal to that plane and offset with respect to the shaft pivot point. In another embodiment the casing and shaft are each a single unit.

Abstract: The piston is formed with a piston head and a sleeve, fitted together such that the piston head has an outer end diameter matching the diameter of the cylinder, and then is formed with an offset inwardly extending shoulder, against which the piston sleeve can bear, to permit machining of the inner face of the piston head to form a bearing cup for a spherical head of a piston rod, and then assembly of the piston sleeve to bear against the abutment; drain line and oil connection lines may be formed in the piston to lead lubricating oil to the bearing cup. The piston head and sleeve can be connected by adhesives and, if necessary, tangentially located transverse pins.