Insert type rotor for radial piston device

1. 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;

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 rotor includes a rotor body and a rotor insert received into the rotor body, wherein the rotor insert includes a plurality of fluid ports;

wherein the rotor defines a plurality of cylinder sets in fluid communication with the plurality of fluid ports of the rotor insert;

wherein the drive shaft includes a stem portion located within the housing such that hydraulic fluid flows around the stem and into an inlet of the pintle, wherein the stem portion tapers in a direction away from the housing hydraulic fluid outlet.

2. The device according to claim 1 , wherein the rotor body defines an axial bore extending along a rotor axis of rotation, the axial bore configured to receive the rotor insert, and wherein the rotor insert defines a pintle bore rotatably mounted on the pintle shaft.

3. The device according to claim 1 wherein the rotor insert is received into the axial bore of the rotor body by either interference fit or shrink fit.

4. The device according to claim 1 , wherein the rotor insert is mounted onto the axial bore of the rotor body with an adhesive or bolt joints.

5. The device according to claim 1 , wherein the rotor body comprises at least partially the plurality of cylinders, and wherein the rotor insert comprises a plurality of rotor fluid ports, each configured to selectively permit the first fluid communication or the second fluid communication.

6. The device according to claim 1 , wherein each of the plurality of cylinder sets defines a first radial cylinder and a second radial cylinder axially spaced from the first radial cylinder, each of the first and second radial cylinders receiving a piston of the plurality of pistons,

wherein each of the rotor fluid ports is configured to correspond to each of the cylinder sets and is in fluid communication with the first and second cylinders of the corresponding cylinder set,

wherein the pintle defines a pintle inlet in fluid communication with the hydraulic fluid inlet and a pintle outlet in fluid communication with the hydraulic fluid outlet, and

wherein the rotor insert fluid ports alternatingly provide fluid communication either between their corresponding first and second cylinders and the pintle inlet, or between their corresponding first and second cylinders and the pintle outlet, as the rotor rotates about the rotor axis.

7. The device according to claim 5 , wherein the plurality of cylinders comprises a first cylinder set, and wherein the plurality of rotor fluid ports comprises a first rotor fluid port that is in fluid communication with the first cylinder set.

8. The device according to claim 1 , wherein the rotor body includes a radial hollow configured to receive the rotor insert, and wherein the rotor body defines a pintle bore rotatably mounted on the pintle shaft.

9. The device according to claim 8 , wherein the rotor insert is received into the radial hollow of the rotor body by either interference fit or shrink fit.

10. The device according to claim 8 wherein the rotor insert is mounted onto the radial hollow of the rotor body with an adhesive or bolt joints.

11. The device according to claim 8 , wherein the rotor insert comprises at least partially the plurality of cylinders, and wherein the rotor body comprises a plurality of rotor fluid ports, each configured to selectively permit the first fluid communication or the second fluid communication.

12. The device according to claim 11 , wherein the plurality of cylinders comprises a first cylinder set, and wherein the plurality of rotor fluid ports comprises a first rotor fluid port that is in fluid communication with the first cylinder set.

13. A radial piston device comprising:

a housing having a hydraulic fluid inlet and a hydraulic fluid outlet;

a pintle attached to the housing, the pintle including a 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 mounted on the pintle shaft, the rotor being configured to rotate relative to the pintle about a rotor axis of rotation that extends through a length of the pintle shaft, the rotor comprising:

a rotor body defining an axial bore extending along the rotor axis of rotation and at least partially defining a plurality of radially oriented cylinders; and

a rotor insert defining a pintle bore rotatably mounted on the pintle shaft and defining a plurality of rotor fluid ports, wherein the rotor insert is fitted into the axial bore and;

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 reciprocate 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 drive shaft includes a stem portion located within the housing such that hydraulic fluid flows around the stem and into the pintle inlet, wherein the stem portion tapers in a direction away from the housing hydraulic fluid outlet.

14. The device according to claim 13 , wherein the rotor insert is received into the axial bore of the rotor body by either interference fit or shrink fit.

15. The device according to claim 13 , wherein the rotor insert is mounted onto the axial bore of the rotor body with an adhesive or bolt joints.

16. The radial piston device according to claim 13 , further comprising a flexible coupling for coupling the drive shaft with the rotor.

17. The radial piston device according to claim 16 , wherein the flexible coupling defines a flexible coupling flow passage in fluidic communication with the hydraulic fluid inlet and the pintle inlet.

18. The radial piston device according to claim 13 , wherein the radial piston device is used as a pump in which torque is input to the drive shaft to rotate the rotor.

19. The radial piston device of claim 18 , wherein the plurality of radially oriented cylinders comprises a first cylinder set, and wherein the plurality of rotor fluid ports comprises a first rotor fluid port that is in fluidic communication with the first cylinder set,

wherein when the rotor is in a first position, the first rotor fluid port is in fluid communication with the pintle inlet, and wherein when the rotor is in a second position substantially opposite to the first position around the pintle shaft, the first rotor fluid port is in fluid communication with the pintle outlet,

wherein when the rotor is in the first position, fluid is drawn from the hydraulic fluid inlet into the first rotor fluid port via the pintle inlet and is drawn radially outward into the first cylinder set, and

wherein when the rotor is in the second position, the fluid is forced from the first cylinder set and the first rotor fluid port into the hydraulic fluid outlet via the pintle outlet.

20. A method of manufacturing a rotor used in a radial piston device, the method comprising:

forming a radial hollow in a rotor body, wherein the rotor body includes a pintle bore configured to be rotatably mounted on a pintle shaft;

forming a plurality of rotor fluid ports in the rotor body;

forming at least partially a plurality of cylinders in the rotor body; and

forming a ridge portion circumferentially at a corner on a bottom surface of the radial hollow, the ridge portion configured to define a common fluid chamber between an inner insert surface of the rotor insert and the bottom surface of the radial hollow;

inserting the rotor insert into the radial hollow of the rotor body such that the plurality of plurality of cylinders are in fluid communication with the plurality of rotor fluid ports.

21. The device of claim 1 , wherein at least some of the plurality of cylinder sets are located axially more proximate to an inlet end of the rotor in comparison to others of the plurality of cylinder sets.

22. The device of claim 1 , wherein the housing defines an interior wall tapering in the same direction as the drive shaft stem portion.