Rotor assembly balancing using a park lock gear and balancing plate

1 . A rotating assembly comprising:

a park lock gear, wherein the park lock gear comprises:

a cylindrical body, wherein the cylindrical body forms an internal spline, wherein a plurality of balancing holes are defined axially through at least a portion of the cylindrical body; and

a plurality of external teeth, wherein the plurality of external teeth extend radially outward from the cylindrical body, wherein the plurality of external teeth define a plurality of external tooth gaps, wherein the plurality of external teeth and the plurality of external tooth gaps are defined in a polar array about a center axis of the park lock gear;

a rotor shaft, wherein the rotor shaft forms an external spline, wherein the internal spline meshes with the external spline;

a rotor, wherein the rotor is configured to magnetically couple with a magnetic field causing the rotating assembly to rotate;

a sensor rotor; and

a balancing plate, wherein the park lock gear, the rotor, the sensor rotor, and the balancing plate are disposed radially outwards of and axially aligned with the rotor shaft, wherein the park lock gear, the rotor, the sensor rotor, and the balancing plate are affixed to and configured to rotate with the rotor shaft, wherein the rotor is disposed axially between the park lock gear and the balancing plate, wherein the park lock gear and the balancing plate are configured to balance the rotating assembly, wherein the park lock gear balances the rotating assembly by the plurality of balancing holes.

2 . The rotating assembly of claim 1 , wherein the park lock gear and the balancing plate statically balance and dynamically balance the rotating assembly.

3 . The rotating assembly of claim 1 , wherein the park lock gear is a ratchet gear, wherein the plurality of external teeth and the plurality of external tooth gaps are straight along an axial length of the park lock gear.

4 . The rotating assembly of claim 1 , wherein the plurality of balancing holes are one of blind-holes or through-holes.

5 . The rotating assembly of claim 4 , wherein the plurality of balancing holes are blind-holes, wherein the plurality of balancing holes are each defined on a same radial face of the cylindrical body.

6 . The rotating assembly of claim 5 , wherein an axial depth of the plurality of balancing holes is a same depth for each of the plurality of balancing holes.

7 . The rotating assembly of claim 5 , wherein the plurality of balancing holes are radially aligned.

8 . The rotating assembly of claim 7 , wherein the plurality of balancing holes are disposed at circumferential positions defined by an arc segment, wherein the arc segment does not fully revolve around the center axis of the park lock gear.

9 . The rotating assembly of claim 7 , wherein the plurality of balancing holes include a spacing between circumferentially adjacent of the plurality of balancing holes such that the plurality of balancing holes do not define a slot.

10 . The rotating assembly of claim 1 , wherein the park lock gear comprises one or more poka-yoke features, wherein the one or more poka-yoke features are configured to circumferentially align the internal spline with the external spline such that the internal spline and the external spline mesh at only one orientation.

11 . The rotating assembly of claim 10 , wherein the internal spline defines the one or more poka-yoke features, wherein the one or more poka-yoke features comprise one or more cuts along one or more teeth of the internal spline.

12 . The rotating assembly of claim 1 , wherein the rotor is disposed axially between the sensor rotor and the balancing plate, wherein the sensor rotor is disposed axially between the park lock gear and the rotor.

13 . The rotating assembly of claim 12 , comprising:

a bearing; and

a sleeve, wherein the bearing and the sleeve are disposed radially outwards of and axially aligned with the rotor shaft, wherein the bearing and the sleeve are affixed to and configured to rotate with the rotor shaft, wherein the rotor is disposed axially between the sensor rotor and the balancing plate, wherein the sensor rotor is disposed axially between the bearing and the rotor, wherein the bearing is disposed axially between the sleeve and the sensor rotor, wherein the sleeve is disposed axially between the park lock gear and the bearing.

14 . The rotating assembly of claim 1 , wherein the park lock gear is configured to lock and unlock rotation of the rotating assembly.

15 . An electric drive unit comprising:

a rotating assembly comprising:

a park lock gear, wherein the park lock gear comprises:

a cylindrical body, wherein the cylindrical body forms an internal spline, wherein a plurality of balancing holes are defined axially through at least a portion of the cylindrical body; and

a plurality of external teeth, wherein the plurality of external teeth extend radially outward from the cylindrical body, wherein the plurality of external teeth define a plurality of external tooth gaps, wherein the plurality of external teeth and the plurality of external tooth gaps are defined in a polar array about a center axis of the park lock gear;

a rotor shaft, wherein the rotor shaft forms an external spline, wherein the internal spline meshes with the external spline;

a rotor, wherein the rotor is configured to magnetically couple with a magnetic field causing the rotating assembly to rotate;

a sensor rotor; and

a balancing plate, wherein the park lock gear, the rotor, the sensor rotor, and the balancing plate are disposed radially outwards of and axially aligned with the rotor shaft, wherein the park lock gear, the rotor, the sensor rotor, and the balancing plate are affixed to and configured to rotate with the rotor shaft, wherein the rotor is disposed axially between the park lock gear and the balancing plate, wherein the park lock gear and the balancing plate are configured to balance the rotating assembly, wherein the park lock gear balances the rotating assembly by the plurality of balancing holes;

a stator; and

a park lock pawl, wherein the park lock gear is configured to and unlock the rotating assembly to and from the stator via the park lock pawl.

16 . The electric drive unit of claim 15 , wherein the park lock pawl comprises a pawl tooth, wherein the park lock pawl is configured to translate the pawl tooth radially inwards to engage with one of the plurality of external tooth gaps and radially outwards to disengage from the one of the plurality of external tooth gaps.

17 . The electric drive unit of claim 15 , comprising a sensor stator, wherein the sensor stator is axially aligned with and disposed radially outwards of the sensor rotor, wherein the sensor stator is configured to sense a rotary position of the rotating assembly via the sensor rotor.

18 . The electric drive unit of claim 15 , comprising an output shaft and a planetary gearset, wherein the output shaft is disposed radially inwards of and axially aligned with the rotor shaft, wherein the output shaft is engaged with the rotating assembly via a differential of the planetary gearset.

19 . A method of assembling a rotating assembly, the method comprising:

affixing a rotor to a rotor shaft;

affixing a balancing plate and a sensor rotor to the rotor shaft;

affixing a park lock gear to the rotor shaft; and

axially drilling the park lock gear and the balancing plate to balance the rotating assembly, wherein the axially drilling forms a plurality of balancing holes,

wherein the rotating assembly comprises the park lock gear, the rotor shaft, the rotor, the balancing plate, and the sensor rotor, wherein the park lock gear comprises:

a cylindrical body, wherein the cylindrical body forms an internal spline, wherein the plurality of balancing holes are defined axially through at least a portion of the cylindrical body; and

a plurality of external teeth, wherein the plurality of external teeth extend radially outward from the cylindrical body, wherein the plurality of external teeth define a plurality of external tooth gaps, wherein the plurality of external teeth and the plurality of external tooth gaps are defined in a polar array about a center axis of the park lock gear;

wherein the rotor shaft forms an external spline, wherein the internal spline meshes with the external spline;

wherein the rotor is configured to magnetically couple with a magnetic field causing the rotating assembly to rotate; and

wherein the park lock gear, the rotor, the sensor rotor, and the balancing plate are disposed radially outwards of and axially aligned with the rotor shaft, wherein the park lock gear, the rotor, the sensor rotor, and the balancing plate are affixed to and configured to rotate with the rotor shaft, wherein the rotor is disposed axially between the park lock gear and the balancing plate, wherein the park lock gear and the balancing plate are configured to balance the rotating assembly, wherein the park lock gear balances the rotating assembly by the plurality of balancing holes.

20 . The method of claim 19 , further comprising:

removing the park lock gear from the rotor shaft;

affixing a bearing and a sleeve to the rotor shaft after the park lock gear is removed from the rotor shaft; and

affixing the park lock gear to the rotor shaft after the bearing and the sleeve are affixed to the rotor shaft,

wherein the rotating assembly comprises the bearing and the sleeve,

wherein the bearing and the sleeve are disposed radially outwards of and axially aligned with the rotor shaft, wherein the bearing and the sleeve are affixed to and configured to rotate with the rotor shaft, wherein the rotor is disposed axially between the sensor rotor and the balancing plate, wherein the sensor rotor is disposed axially between the bearing and the rotor, wherein the bearing is disposed axially between the sleeve and the sensor rotor, wherein the sleeve is disposed axially between the park lock gear and the bearing.