Transverse flux machine with segmented rotor

1 . A transverse flux machine (TFM) comprising:

a rotor assembly configured to rotate about an axis and including a plurality of segments stacked axially, each segment of the plurality of segments including a plurality of rotor cores and a plurality of permanent magnets; and

a stator assembly including a transverse flux core configured to direct a magnetic flux in each of an axial direction and a radial direction toward the rotor assembly,

wherein two segments of the plurality of segments have different lengths in an axial direction,

wherein the plurality of segments of the rotor assembly includes two exterior segments, each of the exterior segments defining an axial end of the rotor assembly,

wherein the plurality of segments of the rotor assembly includes at least one interior segment spaced apart from the axial ends of the rotor assembly, and

wherein the at least one interior segment has a shorter axial length than each of the exterior segments.

2 . The transverse flux machine of claim 1 , wherein the TFM has an internal rotor configuration, with the stator assembly extending annularly about the rotor assembly.

3 . The transverse flux machine of claim 1 , wherein the TFM has an external rotor configuration, with the rotor assembly extending annularly about the stator assembly.

4 . The transverse flux machine of claim 1 , wherein the TFM is a multi-phase machine having a plurality of stator windings, and wherein the transverse flux core of the stator assembly includes a plurality of stator cores, with each of the stator cores defining a ring shape and holding a corresponding stator winding of the plurality of stator windings, and wherein the stator cores are each axially aligned with a corresponding segment of the plurality of segments.

5 . The transverse flux machine of claim 1 , wherein the rotor assembly further includes two adjacent segments of the plurality of segments attached to one-another by a glue joint.

6 . The transverse flux machine of claim 1 , wherein the plurality of permanent magnets include a first set of permanent magnets having a first remnant flux density, and a second set of permanent magnets having a second remnant flux density that is lower than the first remnant flux density.

7 . The transverse flux machine of claim 6 , wherein the first set of permanent magnets having the first remnant flux density are disposed within the exterior segment, and wherein the second set of permanent magnets having the second remnant flux density are disposed within the interior segment.

8 . The transverse flux machine of claim 1 , wherein at least one rotor core of the plurality of rotor cores includes a soft magnetic core (SMC) material.

9 . The transverse flux machine of claim 1 ,

wherein the TFM is a multi-phase machine having at least three stator windings, and wherein the transverse flux core of the stator assembly includes a plurality of stator cores, with each of the stator cores defining a ring shape and holding a corresponding stator winding of the at least three stator windings,

wherein the stator cores are each axially aligned with a corresponding segment of the plurality of segments of the rotor assembly,

wherein each of the exterior segments includes a first set of permanent magnets having a first remnant flux density, and

wherein the at least one interior segment includes a second set of permanent magnets having a second remnant flux density that is lower than the first remnant flux density.

10 . A steer-by-wire system for a vehicle, comprising:

a handwheel actuator coupled to apply a torque to a steering wheel;

the handwheel actuator including a transverse flux machine (TFM), including:

a rotor assembly configured to rotate about an axis and including a plurality of segments stacked axially, each segment of the plurality of segments including a plurality of rotor cores and a plurality of permanent magnets; and

a stator assembly including a transverse flux core configured to direct a magnetic flux in each of an axial direction and a radial direction toward the rotor assembly,

wherein the plurality of segments includes two exterior segments, each of the exterior segments located adjacent to a corresponding axial end of the rotor assembly, and wherein the plurality of segments includes an interior segment which is spaced apart from the axial ends of the rotor assembly, wherein the exterior segments each include a first set of permanent magnets having a first remnant flux density, and the interior segment includes a second set of permanent magnets, and

wherein the interior segment has at least one of: a shorter axial length than the exterior segments, and/or the second set of permanent magnets having a second remnant flux density that is lower than the first remnant flux density of the first set of permanent magnets.

11 . The steer-by-wire system of claim 10 , wherein the handwheel actuator is coupled to the steering wheel via a direct drive mechanism.

12 . The steer-by-wire system of claim 10 , wherein the TFM has an internal rotor configuration, with the stator assembly extending annularly about the rotor assembly.

13 . The steer-by-wire system of claim 10 , wherein the TFM has an external rotor configuration, with the rotor assembly extending annularly about the stator assembly.

14 . The steer-by-wire system of claim 10 , wherein the TFM is a multi-phase machine having a plurality of stator windings, and wherein the transverse flux core of the stator assembly includes a plurality of stator cores, with each of the stator cores defining a ring shape and holding a corresponding stator winding of the plurality of stator windings, and wherein the stator cores are each axially aligned with a corresponding segment of the plurality of segments.

15 . The steer-by-wire system of claim 10 , wherein the rotor assembly further includes two adjacent segments of the plurality of segments attached to one-another by a glue joint.

16 . The steer-by-wire system of claim 10 , wherein the second remnant flux density of the second set of permanent magnets is lower than the first remnant flux density of the first set of permanent magnets.

17 . The steer-by-wire system of claim 10 , wherein at least one rotor core of the plurality of rotor cores includes a soft magnetic core (SMC) material.

18 . The steer-by-wire system of claim 10 , wherein the interior segment has a shorter axial length than the exterior segments.

19 . A transverse flux machine (TFM) comprising:

a rotor assembly configured to rotate about an axis and including a plurality of segments stacked axially, each segment of the plurality of segments including a plurality of rotor cores and a plurality of permanent magnets; and

a stator assembly including a transverse flux core configured to direct a magnetic flux in each of an axial direction and a radial direction toward the rotor assembly,

wherein the plurality of permanent magnets include a first set of permanent magnets having a first remnant flux density, and a second set of permanent magnets having a second remnant flux density that is lower than the first remnant flux density, and

wherein the first set of permanent magnets having the first remnant flux density are disposed within an exterior segment of the plurality of segments located adjacent to an axial end of the rotor assembly, and wherein the second set of permanent magnets having the second remnant flux density are disposed within an interior segment of the plurality of segments which is spaced apart from the axial end of the rotor assembly.

20 . The transverse flux machine of claim 19 , wherein the TFM is a multi-phase machine having a plurality of stator windings, and wherein the transverse flux core of the stator assembly includes a plurality of stator cores, with each of the stator cores defining a ring shape and holding a corresponding stator winding of the plurality of stator windings, and wherein the stator cores are each axially aligned with a corresponding segment of the plurality of segments.