Methods and apparatus pertaining to positive displacement pumps, and further to hydraulic actuation systems. In some embodiments the pumps are gear pumps with bi-directional operation. In some embodiments the actuation system includes a motor-driven, reversible operation gear pump providing fluid under pressure to a rod and cylinder.

Methods and apparatus pertaining to positive displacement pumps, and further to hydraulic actuation systems. In some embodiments the pumps are gear pumps with bi-directional operation. In some embodiments the actuation system includes a motor-driven, reversible operation gear pump providing fluid under pressure to a rod and cylinder.

A fluid pump for a linear actuator is provided. The pump causes a rod in the actuator to extend or retract by controlling the flow of fluid to and from portions of a fluid chamber on either side of a piston disposed within the fluid chamber and supporting the rod. The pump includes a valve structure that enables the pump to redistribute fluid obtained from one portion of the fluid chamber on one side of the piston to the other portion of the fluid chamber on the other side of the piston without first returning the fluid to a fluid reservoir thereby increasing the efficiency of the pump.

A fluid pump for a linear actuator is provided. The pump causes a rod in the actuator to extend or retract by controlling the flow of fluid to and from portions of a fluid chamber on either side of a piston disposed within the fluid chamber and supporting the rod. The pump includes a valve structure that enables the pump to redistribute fluid obtained from one portion of the fluid chamber on one side of the piston to the other portion of the fluid chamber on the other side of the piston without first returning the fluid to a fluid reservoir thereby increasing the efficiency of the pump.

The invention relates to a pump (2) intended to pump an additive in an SCR system for a vehicle. The pump is configured to rotate in a first direction of rotation in order to convey additive stored in a tank towards an injector via an injection channel. The pump includes a chamber (23) which houses a gear system (22). The chamber (23) is in fluid communication with the tank and the injection channel via an inlet channel (24) and an outlet channel (25) respectively. The pump is such that the inlet channel and the outlet channel are arranged so that after draining the injection channel, the chamber collects and retains the additive.

A central distribution unit (CDU) for circulating coolant is disclosed. The CDU may operate under negative pressure and can have a number of operation modes including: normal operation, pump priming, fill, drain, purge and vacuum test. The CDU includes various valves, pumps and sensors, the placement and actuation of which transitions the CDU into the various modes.

A pump with two independent motors is disclosed. The first motor is mechanically connected to a first rotor comprising a first plurality of teeth radiating from the center of the first rotor. The second motor is mechanically connected to a second rotor comprising a second plurality of teeth radiating from the center of the first rotor, wherein the first plurality meshes with the second plurality. A sealed case may house the first and second rotors, and the case may include a suction inlet and a pressure outlet. Rotating the rotors propels a liquid from the suction inlet to the pressure outlet. Because the motors are independent of each other, when one motor fails to rotate the other motor will rotate both rotors and maintain the propelling liquid from the suction inlet to the pressure outlet. The pump may be a gear pump or a rotary lobe pump.

A rotational mechanical transformer has been arranged for transfer and transformation of velocity, force, angular momentum, torque, energy/work, energy density, and pressure, associated with at least one rotating device. The transformer includes an actuator having at least one cylinder arranged to contain the at least one working fluid, an externally supported shaft and a drive shaft having parallel axes orthogonally displaced by a predetermined displacement, and each respectively connected to at least one connecting arm and at least one additional connecting arm. The at least one cylinder includes at least one actuator rod and at least one blind end each respectively connected with at least one revolving eccenter axle and the at least one drive shaft, and have been arranged to allow for angular displacements of the at least one actuator with respect to the parallel axis.

A rotational mechanical transformer has been arranged for transfer and transformation of velocity, force, angular momentum, torque, energy/work, energy density, and pressure, associated with at least one rotating device. The transformer includes an actuator having at least one cylinder arranged to contain the at least one working fluid, an externally supported shaft and a drive shaft having parallel axes orthogonally displaced by a predetermined displacement, and each respectively connected to at least one connecting arm and at least one additional connecting arm. The at least one cylinder includes at least one actuator rod and at least one blind end each respectively connected with at least one revolving eccenter axle and the at least one drive shaft, and have been arranged to allow for angular displacements of the at least one actuator with respect to the parallel axis.

This disclosure generally relates to an automatic bicycle, particularly to a hydraulic automatic transmission bicycle which can automatically and adaptively change gear ratios. More particularly, this disclosure relates to those hydraulic automatic transmission bicycles which use fluid pressure to change such gear ratios, and which include various hydraulic automatic transmissions which may be provided in various configurations and may operate in various methods and sequences to provide automatic and infinitely variable gear ratios.