Radial piston device with reduced pressure drop

A radial piston device comprising:

• a housing having a hydraulic fluid inlet and a hydraulic fluid outlet;
• a pintle attached to the housing and having a pintle shaft, wherein the pintle shaft defines a pintle inlet and a pintle outlet, the pintle inlet in fluid communication with the hydraulic fluid inlet, and the pintle outlet in fluid communication with the hydraulic fluid outlet;
• a rotor mounted on the pintle shaft and configured to rotate relative to the pintle about a rotor axis of rotation that extends through a length of the pintle shaft, the rotor defining a plurality of radially oriented cylinder;
• a plurality of pistons, each being displaceable in each of the plurality of cylinders;
• and
• a drive shaft rotatably supported within the housing and having a driving end and a power transfer end, the drive shaft including a shaft body at the driving end, a power transfer flange at the power transfer end, and a stem connecting the shaft end and the power transfer flange between the driving end and the power transfer end, wherein the power transfer flange is coupled to the rotor and defines a drive shaft flow passage between the hydraulic fluid inlet and the pintle inlet of the pintle shaft,
• wherein the stem includes a plurality of arms and an arm connection point, the plurality of arms extending from the power transfer flange and connected to the arm connection point, the plurality of arms having portions radially offset from a shaft axis of rotation, and the arm connection point connected to the shaft body, wherein the arm connection point is arranged to be axially offset from the drive shaft flow passage toward the shaft body.

A radial piston device comprising:

• a housing having a hydraulic fluid inlet and a hydraulic fluid outlet;
• a pintle having a first end and a second end opposite to the first end along a pintle axis, the pintle attached to the housing at the first end and having a pintle shaft between the first end and the second end, wherein the pintle shaft defines a pintle inlet and a pintle outlet, the pintle inlet in fluid communication with the hydraulic fluid inlet at the second end, and the pintle outlet in fluid communication with the hydraulic fluid outlet at the first end;
• a rotor mounted on the pintle shaft and configured to rotate relative to the pintle about a rotor axis of rotation that extends through a length of the pintle shaft, the rotor defining a plurality of radially oriented cylinders and defining a plurality of rotor fluid ports;
• a plurality of pistons, each being displaceable in each of the plurality of cylinders;
• a drive shaft rotatably supported within the housing and having a driving end and a power transfer end, the drive shaft including a shaft body at the driving end, a power transfer flange at the power transfer end, and a stem connecting the shaft end and the power transfer flange between the driving end and the power transfer end, wherein the power transfer flange is coupled to the rotor and defines a drive shaft flow passage between the hydraulic fluid inlet and the pintle inlet of the pintle shaft;
• and
• a funnel coupled to the pintle shaft at the second end thereof and configured to be open to the drive shaft flow passage to guide a hydraulic fluid from the hydraulic fluid inlet to the pintle inlet, the funnel arranged to remain stationary with respect to the pintle shaft as the rotor rotates about the pintle shaft.

A radial piston device comprising:

• a housing having a hydraulic fluid inlet and a hydraulic fluid outlet;
• a pintle having a first end and a second end opposite to the first end along a pintle axis, the pintle attached to the housing at the first end and having a pintle shaft between the first end and the second end, wherein the pintle shaft defines a pintle inlet and a pintle outlet, the pintle inlet in fluid communication with the hydraulic fluid inlet at the second end, and the pintle outlet in fluid communication with the hydraulic fluid outlet at the first end;
• a rotor having a pintle bore mounted onto the pintle shaft, the rotor configured to rotate relative to the pintle about a rotor axis of rotation that extends through a length of the pintle shaft, the rotor defining a plurality of radially oriented cylinders and defining a plurality of rotor fluid ports;
• a plurality of pistons, each being displaceable in each of the plurality of cylinders;
• and
• a drive shaft rotatably supported within the housing and having a driving end and a power transfer end, the drive shaft including a shaft body at the driving end, a power transfer flange at the power transfer end, and a stem connecting the shaft end and the power transfer flange between the driving end and the power transfer end, wherein the power transfer flange is coupled to the rotor and defines a drive shaft flow passage between the hydraulic fluid inlet and the pintle inlet of the pintle shaft;
• and
• wherein the plurality of cylinders is in paired configuration to form cylinder sets including at least two cylinders, the at least two cylinders located adjacent one another along an axis parallel to a rotor axis, wherein the cylinder sets are offset from one another along an axis parallel to the rotor axis,
• wherein the rotor has a rotor inlet face and a rotor outlet face,
• wherein a first group of the cylinder sets are arranged closer to the rotor inlet face than to the rotor outlet face, and a second group of the cylinder sets are arranged closer to the outlet face than to the rotor inlet face,
• wherein the rotor includes common fluid chambers configured to provide a fluid communication between the cylinder sets and the rotor fluid ports, respectively,
• wherein a first group of the common fluid chambers are formed from the rotor inlet face along an axis parallel to the rotor axis, the first group of the common fluid chambers associated with the second group of the cylinder sets, and
• wherein a second group of the common fluid chambers are formed from the rotor outlet face along an axis parallel to the rotor axis, the second group of the common fluid chambers associated with the first group of the cylinder sets.

A radial piston device comprising:

• a housing having a hydraulic fluid inlet, an inlet chamber, and a hydraulic fluid outlet, the inlet chamber having a first chamber end and a second chamber end along a longitudinal axis of the housing;
• a pintle attached to the housing, the pintle including a pintle shaft defining a pintle inlet and a pintle outlet, the pintle inlet arranged adjacent the second chamber end of the inlet chamber and being in fluid communication with the hydraulic fluid inlet through the inlet chamber, and the pintle outlet being in fluid communication with the hydraulic fluid outlet;
• a rotor mounted on the pintle shaft and configured to rotate relative to the pintle about a rotor axis of rotation that extends through a length of the pintle shaft, the rotor defining a plurality of radially oriented cylinders and defining a plurality of rotor fluid ports;
• a plurality of pistons, each being displaceable in each of the plurality of radially oriented cylinders, wherein the plurality of rotor fluid ports are in fluid communication with the plurality of radially oriented cylinders, and wherein the plurality of rotor fluid ports are alternately in fluid communication with either the pintle inlet or the pintle outlet as the rotor rotates relative to the pintle about the rotor axis of rotation;
• a thrust ring disposed about the rotor, wherein the thrust ring is in contact with each of the plurality of pistons, and wherein the thrust ring has a thrust ring axis that is radially offset from the rotor axis of rotation so that the plurality of pistons reciprocates radially within the rotor as the rotor rotates about the rotor axis of rotation;
• and
• a drive shaft being coupled to the rotor and rotatably supported within the housing,
• wherein the inlet chamber has a side wall extending between the first chamber end and the second chamber end, the side wall configured to have a cross-sectional area of the inlet chamber at the first chamber end smaller than a cross-sectional area of the inlet chamber at the second chamber end.

A device comprising:

• a housing having a hydraulic fluid inlet and a hydraulic fluid outlet;
• a pintle attached to the housing and having a pintle shaft, the pintle shaft defining a pintle inlet and a pintle outlet, the pintle inlet being in fluid communication with the hydraulic fluid inlet, the pintle outlet being in fluid communication with the hydraulic fluid outlet;
• a rotor rotatably mounted on the pintle shaft and having a plurality of cylinders;
• a plurality of pistons, each being displaceable in each of the plurality of cylinders;
• and
• a drive shaft coupled to the rotor and rotatably supported within the housing,
• wherein the pintle shaft defines a first fluid communication between the hydraulic fluid inlet and at least part of the plurality of cylinders and a second fluid communication between at least part of the plurality of cylinders and the hydraulic fluid outlet, and
• wherein the pintle includes a pintle wall extending at least partially within the pintle shaft along a pintle axis.