Electric motor rotor with extended shoulders for bearings

1. A product comprising:

a rotor core comprising a body, wherein the body includes an inner surface constructed and arranged to accommodate a shaft and an outer surface, a first end cap which extends radially from a first end of the body and a second end cap which extends radially from a second end of the body, wherein the first end cap, the second end cap, and the outer surface define an annular cavity;

at least one magnet contained within the annular cavity;

at least one bearing surface component adjacent at least one of the first end cap or the second end cap which extends axially outward from an outer surface of at least one of the first end cap or the second end cap, wherein the bearing surface component is a shoulder which extends axially from the first end cap or the second end cap and is one single continuous component with the first end cap or the second end cap; and

at least one bearing operatively attached to the at least one bearing surface component.

2. The product of claim 1 wherein the at least one bearing is a hydrodynamic bearing.

3. The product of claim 1 wherein the at least one bearing is a rolling element bearing.

4. The product of claim 1 wherein the at least one bearing surface component is an inner race for the at least one bearing.

5. The product of claim 1 further comprising a stator surrounding the rotor assembly, and wherein the rotor assembly is operatively attached to the shaft, and wherein the shaft is part of a turbo machine.

6. The product of claim 1 wherein at least one of the first end cap or the second end cap further comprises an axial lip constructed and arranged to position the at least one bearing.

7. A rotor assembly comprising:

a rotor core comprising: a body, wherein the body is cylindrical and includes an inner surface and an outer surface, wherein the inner surface is constructed and arranged to accommodate a shaft; a first end cap which extends radially from a first end of the body and a second end cap which extends radially from a second end of the body; an annular cavity defined by a portion of the outer surface of the body, an inner surface of the first end cap, and an inner surface of the second end cap;

at least one bearing sleeve which extends axially from an outer surface of the first end cap or the second end cap, wherein the at least one bearing sleeve is one single continuous component and is an inner running surface for a hydrodynamic bearing;

at least one magnet within the annular cavity; and

a rotor sleeve surrounding the annular cavity.

8. The rotor assembly of claim 7 wherein the at least one bearing sleeve is one single continuous component with the rotor core.

9. The rotor assembly of claim 7 wherein the at least one bearing sleeve is a separate component from the rotor core.

10. The rotor assembly of claim 7 further comprising at least one hydrodynamic bearing operatively attached to the at least one bearing sleeve.

11. The rotor assembly of claim 7 wherein at least one of the first end cap or the second end cap further comprises an axial lip having a thrust surface for at least one bearing.

12. A rotor core comprising:

a body, wherein the body is cylindrical and includes an inner surface constructed and arranged to accommodate a shaft and an outer surface;

a first end cap which extends radially from a first end of the body and a second end cap which extends radially from a second end of the body;

an annular cavity defined by a portion of the outer surface of the body, an inner surface of the first end cap, and an inner surface of the second end cap; and

at least one shoulder which extends axially from an outer surface of one of the first end cap or the second end cap and is one single continuous component with the first end cap or the second end cap and which is constructed and arranged to act as an inner bearing surface.

13. The rotor core of claim 12 wherein the bearing surface is an inner running surface for at least one hydrodynamic bearing.

14. The rotor core of claim 13 further comprising the at least one hydrodynamic bearing operatively attached to the at least one shoulder.

15. The rotor core of claim 12 wherein the inner bearing surface is an inner race for a rolling element bearing.

16. The rotor core of claim 15 further comprising operatively attaching a plurality of rolling elements and a bearing outer race to the inner race.

17. The rotor core of claim 12 wherein at least one of the first end cap or the second end cap further comprises an axial lip which extends away from the body.