A hydraulic motor includes a rotor and a stator, wherein the rotor and the stator define a plurality of motor pockets for receiving a flow of hydraulic fluid, and the rotor rotates relative to the stator based on a pressure differential between the motor pockets. A commutator having porting controls the flow of hydraulic fluid into the motor pockets. The rotor rotates about a first axis and the stator orbits about a second axis, and the stator is configured to orbit such that the second axis orbits about the first axis. The commutator is eccentrically piloted about the first axis and the second axis so that the commutator both rotates and orbits to control the flow of hydraulic fluid into the motor pockets. With such configuration, an output shaft is driven by rotation of the rotor about the first axis without orbiting, obviating the need for a drive link.

A hydraulic motor includes a rotor and a stator, wherein the rotor and the stator define a plurality of motor pockets for receiving a flow of hydraulic fluid, and the rotor rotates relative to the stator based on a pressure differential between the motor pockets. A commutator having porting controls the flow of hydraulic fluid into the motor pockets. The rotor rotates about a first axis and the stator orbits about a second axis, and the stator is configured to orbit such that the second axis orbits about the first axis. The commutator is eccentrically piloted about the first axis and the second axis so that the commutator both rotates and orbits to control the flow of hydraulic fluid into the motor pockets. With such configuration, an output shaft is driven by rotation of the rotor about the first axis without orbiting, obviating the need for a drive link.

A control ring for controlling the flow of a pressure medium in a displacement pump is provided. The control extends along a first rotational axis, and includes a first and a second axial surface. The first axial surface has an interface section provided with at least a first and a second opening, which first and second openings are arc shaped and are separated by a first and a second land. The first land is provided with a first tapered groove extending from the first opening into the first land, and having its broader edge in a direction of the first opening and its tip in a direction of the second opening. The first tapered groove extends into the first land such that an angular distance between the first and second openings over the first land is different at different radial distances.

A control ring for controlling the flow of a pressure medium in a displacement pump is provided. The control extends along a first rotational axis, and includes a first and a second axial surface. The first axial surface has an interface section provided with at least a first and a second opening, which first and second openings are arc shaped and are separated by a first and a second land. The first land is provided with a first tapered groove extending from the first opening into the first land, and having its broader edge in a direction of the first opening and its tip in a direction of the second opening. The first tapered groove extends into the first land such that an angular distance between the first and second openings over the first land is different at different radial distances.

A commutator/manifold assembly controls a flow of hydraulic fluid in a hydraulic fluid system. The assembly includes a commutator having an offset design including an inner portion eccentrically encompassed within an outer portion, and offset commutator porting to control the hydraulic flow. A manifold includes manifold ports having a straight configuration by which walls defining the manifold ports run substantially along a longitudinal axis through an entirety of the manifold. The commutator is configured to rotate to sequentially align the commutator porting with differing portions of the manifold ports to control the flow. The commutator porting includes inner ports and outer ports that are isolated from each other by a commutator seal. A commutator ring has a guiding surface that guides rotation of the commutator. The rotation of the commutator provides a timed flow through the manifold ports straight through the manifold and without any directional flow restriction.

A commutator/manifold assembly controls a flow of hydraulic fluid in a hydraulic fluid system. The assembly includes a commutator having an offset design including an inner portion eccentrically encompassed within an outer portion, and offset commutator porting to control the hydraulic flow. A manifold includes manifold ports having a straight configuration by which walls defining the manifold ports run substantially along a longitudinal axis through an entirety of the manifold. The commutator is configured to rotate to sequentially align the commutator porting with differing portions of the manifold ports to control the flow. The commutator porting includes inner ports and outer ports that are isolated from each other by a commutator seal. A commutator ring has a guiding surface that guides rotation of the commutator. The rotation of the commutator provides a timed flow through the manifold ports straight through the manifold and without any directional flow restriction.

A driving power transmission device includes a fluid pressure type clutch device that transmits driving power between two shaft members, and a pump that supplies a fluid to the clutch device. The pump includes a pump that makes a pressure of sucked fluid high; a first flow passage through which the fluid according to a pressure discharged from the pump is supplied to the clutch device during a driving of the pump; a second flow passage through which the fluid discharged from the pump is held during a stop of the pump and a pressing force is applied to the clutch device by the fluid to be held; and a switching valve that is switchable between a normal mode where a discharge port of the pump communicates with the first flow passage and a locking mode where the discharge port of the pump communicates with the second flow passage.

A driving power transmission device includes a fluid pressure type clutch device that transmits driving power between two shaft members, and a pump that supplies a fluid to the clutch device. The pump includes a pump that makes a pressure of sucked fluid high; a first flow passage through which the fluid according to a pressure discharged from the pump is supplied to the clutch device during a driving of the pump; a second flow passage through which the fluid discharged from the pump is held during a stop of the pump and a pressing force is applied to the clutch device by the fluid to be held; and a switching valve that is switchable between a normal mode where a discharge port of the pump communicates with the first flow passage and a locking mode where the discharge port of the pump communicates with the second flow passage.

A pump apparatus with a switching valve includes an actuator that is rotationally driven, a pump, a switching valve and a driving power interrupting device. The pump discharges a fluid sucked by rotational driving of the actuator. The switching valve is changed in phase by the rotational driving of the actuator so as to be switchable among a plurality of destinations of the fluid discharged from a pump chamber of the pump. The driving power interrupting device for a valve is switchable between a state where rotational driving power of the actuator is transmitted to the switching valve and a state where the rotational driving power of the actuator is interrupted.

A pump apparatus with a switching valve includes an actuator that is rotationally driven, a pump, a switching valve and a driving power interrupting device. The pump discharges a fluid sucked by rotational driving of the actuator. The switching valve is changed in phase by the rotational driving of the actuator so as to be switchable among a plurality of destinations of the fluid discharged from a pump chamber of the pump. The driving power interrupting device for a valve is switchable between a state where rotational driving power of the actuator is transmitted to the switching valve and a state where the rotational driving power of the actuator is interrupted.