Abstract: An improved drive shaft is disclosed of the type used in a rotary fluid pressure device including an input-output shaft and a gerotor gear set having an externally toothed member which orbits and rotates within an internally toothed member. Both the input-output shaft and the externally toothed member define straight internal splines, and the drive shaft includes a set of crowned, involute external splines at each end thereof, in engagement with the respective straight internal splines. The crowned external splines are hobbed with a hob on which the cutter teeth have a pressure angle .phi..sub.H greater than the primary pressure angle .phi..sub.S of the crowned splines. The increased pressure angle .phi..sub.H of the cutter teeth makes it possible to reduce the crown angle on the splines, while still maintaining the necessary clearance X between each external spline and the adjacent internal spline at any given axial distance Y along the external spline from the central plane.

Abstract: A rotary fluid pressure device such as a motor or pump of the type utilizing a Geroler.RTM. gear set. The internal teeth of the Geroler.RTM. are tubular members mounted on bearings to be slightly movable. Between each adjacent pair of tubular teeth is a check valve in the form of a roller which is mounted to be movable slightly more than are the tubular teeth. A resilient band surrounds the rollers, biasing each of them inwardly toward engagement with the adjacent teeth, but permitting each of the roller check valves to move out of sealing engagement with the adjacent teeth when the fluid pressure in the adjacent volume chamber exceeds the combined biasing force of the resilient band and the fluid in the outer fluid chamber. The invention provides a low cost Geroler.RTM. gear set permitting greater manufacturing tolerances, and having improved low speed characteristics and volumetric efficiency, resulting from minimized tooth-tip leakage.

Abstract: A rotary fluid pressure device of the type including agerotor gear set having an externally-toothed rotor orbiting and rotating within an internally-toothed stator. An intermediate shaft has one end in splined engagement with the rotor and the other end defining a large set of internal splines. The device includes an output shaft assembly, also defining a large set of internal splines. A large dogbone shaft having external splines at each end transmits torque between the intermediate shaft and the output shaft assembly. The intermediate shaft has an axial bore which communicates pressurized lubricant to the one end of the dogbone shaft, a portion of the pressurized lubricant flowing radially outward over the end of the dogbone and through the spline connection between the dogbone and the intermediate shaft.

Abstract: A rotary fluid pressure device of the type including a gerotor gear set having an externally-toothed rotor orbiting and rotating within an internally-toothed stator. An intermediate shaft has one end in splined engagement with the rotor and the other end defining a large set of internal splines. The device includes an output shaft assembly, also defining a large set of internal splines, with a large dogbone shaft transmitting torque between the intermediate shaft and the output shaft assembly. A portion of the housing disposed between the gerotor gear set and the end of the intermediate shaft defining the internal splines is engaged by the enlarged portion of the intermediate shaft, resulting in large and random axial forces being exerted by the intermediate shaft. To absorb such thrust forces, a wear ring is seated within a recess formed in the housing portion and includes an annular wear surface defining an axis substantially coincidental with the axis of the internally-toothed stator.

Abstract: A stator-rotor assembly wherein rollers are used to form the internal teeth of the stator. The rotor has one less tooth than the stator and cooperates in gear relationship with the internal teeth of the stator. The stator has a plurality of cylindrically shaped pockets each containing a cylindrical roller. Each pocket is covered with a crushable porous coating to a thickness of X units. The radius of the pocket is R units and the radius of the rollers is equal to or greater than R-X units and less than R units. Each roller crushes the coating at spaced locations to trap fluid between the rollers and the pocket. The rotor has an average diameter that interferes with the tangent circle of the stator-roller assembly.

Abstract: Fluid inlet and outlet porting for a rotary fluid displacement device including a housing defining a cylindrical chamber and a pair of cooperating respective internally and externally toothed ring and star members in the chamber, the ring member encompassing the star member and having teeth at least one more in number than the star member, the members rotating on spaced parallel axes with the teeth thereof moving into and out of intermeshing engagement to provide alternately expanding and contracting fluid compartments. Inlet and outlet ports opening respectively to the expanding and contracting chambers, extend generally circumferentially of the ring member, the inlet port having one end in the shape of portions of the teeth of the ring and star members, said one end of the inlet port being disposed adjacent an area wherein the teeth of the members are out of intermeshing engagement.

Abstract: A casing, formed to provide fluid inlet and outlet openings and a stationary internal gear intermediate the openings, the casing journaling a rotary shaft coaxial with the internal gear. Primary and secondary rotors are fixed on the shaft in axially spaced relationship, the primary rotor having fluid passages communicating with one of the openings. A fluid transfer element is fixed on the shaft between the secondary rotor and an end of the casing, and defines a fluid passage communicating with the other casing opening. The primary rotor includes a rotary internal gear disposed near the stationary internal gear. The secondary rotor has a plurality of external tooth elements, and a cooperating ring is eccentrically mounted thereon, the ring having internal tooth elements one more in number than those of the secondary rotor. The tooth elements cooperate to define inner and outer walls of successively expanding and contracting fluid chambers.