Methods and systems for oil cooled rotor laminations

1. A system for cooling an electric motor, comprising:

a rotor shaft rotatably mounted inside a motor housing;

a lamination stack integrally connected to the rotor shaft;

an encoder-end balance plate integrally connected to a first end of the lamination stack and a first end of the rotor shaft;

an output-end balance plate integrally connected to a second end of the lamination stack and a second end of the rotor shaft; and

a coolant supply coupled to the output-end balance plate and the rotor shaft;

wherein a closed-loop coolant pathway is sequentially formed between the coolant supply, the rotor shaft, the encoder-end balance plate, the lamination stack, and the output-end balance plate; and

wherein the closed-loop coolant pathway includes:

a hollow portion of the rotor shaft in which coolant is flowed from an output end of the rotor shaft towards an encoder end of the rotor shaft;

a plurality of holes in the rotor shaft adjacent to the encoder end that are fluidly connected to a plurality of inner pathways in the encoder-end balance plate; and

a plurality of axial channels in the lamination stack that are fluidly connected to a recessed region of the encoder-end balance plate;

wherein coolant flows radially outward through the plurality of holes and the plurality of inner pathways.

2. The system of claim 1 , wherein the closed-loop coolant pathway includes one or more passages and/or recesses of the output-end balance plate that receive coolant from the plurality of axial channels.

3. The system of claim 2 , wherein the closed-loop coolant pathway flows coolant from the one or more passages and/or recesses of the output-end balance plate to the coolant supply.

4. The system of claim 1 , wherein the encoder-end balance plate is sealed to the first end of the lamination stack and the first end of the rotor shaft.

5. The system of claim 1 , wherein the output-end balance plate is sealed to the second end of the lamination stack and the second end of the rotor shaft.

6. The system of claim 1 , further comprising an output end bearing in contact with the output-end balancing plate.

7. The system of claim 1 , wherein the encoder-end balance plate encompasses the plurality of holes of the rotor shaft.

8. An electric motor comprising:

an encoder-end balance plate including a central aperture surrounded by a recessed region;

an output-end balance plate including a central aperture, a recessed region, grooves, a plurality of holes, and a plurality of supports in contact with an end of a lamination stack of a rotor;

wherein the rotor is coupled to the encoder-end balance plate and the output-end balance plate; and

wherein the encoder-end balance plate is configured to divert oil from a rotor shaft to axial holes within a rotor and the output-end balance plate is configured to divert the oil from the axial holes in the rotor to an oil pump; and

a closed-loop oil pathway including:

a hollow portion of the rotor shaft in which oil is flowed from an output end of the rotor shaft towards an encoder end of the rotor shaft;

a plurality of holes in the rotor shaft adjacent to the encoder end that are fluidly connected to a plurality of inner pathways in the encoder-end balance plate; and

a plurality of axial channels in the lamination stack that are fluidly connected to the recessed region of the encoder-end balance plate.

9. The electric motor of claim 8 , wherein the output-end balance plate includes a disk shaped top portion connected to a tubular shaft, with the central aperture running through the top portion and the tubular shaft.

10. The electric motor of claim 9 , wherein the top portion includes the recessed region and a support face that surrounds the central aperture, the support face including a plurality of holes that continue into a shell comprising the tubular shaft.

11. The electric motor of claim 10 , wherein the plurality of holes are traversed by a first groove within the support face and terminate within a second groove that surrounds an outer perimeter of the tubular shaft.

12. The electric motor of claim 10 , wherein the recessed region connects with the plurality of axial channels within the rotor.

13. The electric motor of claim 8 , further comprising a locking nut coupled to the output end of the rotor shaft and clamping the lamination stack between the output-end balancing plate and the encoder-end balancing plate.

14. The electric motor of claim 8 , wherein the one or more holes are encompassed by the recessed region of the encoder-end balance plate.

15. The electric motor of claim 14 , wherein the recessed region is connected to the plurality of axial channels within the rotor.