Geroller hydraulic motor with anti-cogging structure

A hydraulic motor comprising:

• a drive assembly, a manifold, and a wear plate;
• said drive assembly including a stator and a rotor,
• each of said stator and said rotor having a longitudinal axis, the longitudinal axis of said stator being parallel to and spaced from the longitudinal axis of said rotor, each of said stator and said rotor having first and second end faces;
• at least one of said stator and said rotor including a plurality of rollers, each of said rollers having a longitudinal axis substantially perpendicular to the longitudinal axes of said stator and said rotor, each of said rollers having a generally circular outer surface and having first and second end faces, said circular surfaces of said rollers defining a first set of teeth that engage a second set of teeth on the other of said stator and said rotor, said first and second set of teeth defining expanding and contracting fluid chambers;
• said manifold including a surface adjacent to said first end faces of said stator and said rotor, a plurality of working fluid passages extending through said manifold surface, each of said fluid chambers being in fluid pressure communication with at least one of said manifold fluid passages;
• said wear plate including a surface adjacent to said second end faces of said stator and said rotor;
• and an anti-cogging fluid passage in at least one of said wear plate and said manifold, said anti-cogging passage extending between and establishing fluid pressure communication between one of said fluid chambers and one of said first and second end faces of said rollers.

A low speed high torque geroller hydraulic motor comprising:

• a drive assembly, a manifold, a wear plate and a housing;
• said drive assembly including a stator and a rotor,
• each of said stator and said rotor having a longitudinal axis, said longitudinal axis of said stator being parallel to and spaced from said longitudinal axis of said rotor, each of said stator and said roller having first and second radial end faces, said first radial end faces being coplanar in a first plane that is perpendicular to said longitudinal axes, said second radial end faces being coplanar in a second plane that is parallel to said first plane;
• said stator including a plurality of rollers, each of said rollers having a longitudinal axis perpendicular to the longitudinal axes of said stator and said roller, each of said rollers having a generally circular outer surface extending in the longitudinal direction of the roller and having first and second radial end faces, said first and second radial end faces of said rollers being coplanar with said first and second planes respectively of said radial end faces of said stator and said roller, said circular surfaces of said rollers defining a first set of teeth that effectively engage a second set of teeth on the other of said stator and said rotor in a moving longitudinally extending contact line upon relative rotational movement of said stator and said rotor, radially adjacent teeth of said first and second set of teeth defining expanding and contracting fluid chambers between circumferentially adjacent moving contact lines, and the fluid chamber on one side of said contact line being at a higher fluid pressure level relative to the fluid chamber on the other side of said contact line during operation of said motor;
• said manifold including a radial end face longitudinally immediately adjacent to and parallel with said first radial end faces of said stator and said rotor, a plurality of fluid passages extending longitudinally through said manifold end face, each of said fluid chambers being in fluid pressure communication with at least one of said manifold end face fluid passages;
• said wear plate including a radial end face longitudinally immediately adjacent to and and parallel with said second radial end faces of said stator and said rotor;
• said housing including an inner cavity, a drive link disposed in said inner cavity and mechanically connected to one of said stator and said rotor;
• and a plurality of anti-cogging fluid passages in said wear plate radial end face and in said manifold radial end face, said anti-cogging passages in said manifold radial end face establishing fluid communication between said fluid chamber on one side of each contact line and the first radial end face of the particular roller that engages a radially adjacent tooth to define said contact line, and said anti-cogging passages in said wear plate radial end face establishing fluid communication between said fluid chamber on said one side of said contact line and the second radial end face of said particular roller