Search

DE-102024132730-A1 - Stator for a radial flux twin-rotor machine and radial flux twin-rotor machine

DE102024132730A1DE 102024132730 A1DE102024132730 A1DE 102024132730A1DE-102024132730-A1

Abstract

The present invention relates to a stator for a radial flux twin-rotor machine, in particular for a wheel hub motor, comprising a stator core with a flow-through cooling device for cooling the stator; a winding placed in the stator core, which is self-supporting for torque support of the stator and projects beyond the stator core at a first axial end and a second axial end arranged opposite the first axial end; wherein torque support of the winding is provided at the first axial end, and the stator core contains stator slots extending according to the winding path for arranging a single conductor bar of the winding, wherein the stator slots have a groove base located in the stator core that has a widening relative to the stator slot, forming a channel for an axial coolant flow of the flow-through cooling device. The present invention further relates to a radial flux rotor machine for a wheel hub drive with such a stator.

Inventors

  • Alexander Rosen
  • Lukas Michels

Assignees

  • DeepDrive GmbH

Dates

Publication Date
20260513
Application Date
20241108

Claims (16)

  1. Stator (1) for a radial flux twin-rotor machine, in particular for a wheel hub motor, comprising: a stator core (3) having a flow-through cooling device (2) for cooling the stator (1); a winding (4) placed in the stator core (3), which is self-supporting for torque support of the stator (1) and projects beyond the stator core (3) at a first axial end (5) and a second axial end (6) arranged opposite the first axial end (5); wherein a torque support of the winding (4) is provided at the first axial end (5), and the stator core (3) contains stator slots (7) extending in accordance with a winding path for arranging a single conductor bar (8) of the winding (4), whereby the stator slots (7) have a slot base (9) located in the stator core (3) which has a widening relative to the stator slot (7) and which forms a channel (22) for an axial coolant flow (KS) of the flow-through cooling device (2).
  2. Stator (1) after Claim 1 , characterized in that each of the stator slots (7) has the widening and/or the widening extends in the radial and/or tangential direction of the stator slot (7) into the stator core (3).
  3. Stator (1) after Claim 1 or 2 , characterized in that the stator core (3) has a division (10) into separate stator core areas (11a, b), wherein the lines (22) in the stator core areas (11a, b) are optionally provided for an introduction (E) of the coolant flow (KS) into the lines (22) from the first to the second axial end (5, 6) or for a return flow (R) of the coolant flow (KS) from the second to the first axial end (5, 6).
  4. Stator (1) after Claim 3 , characterized in that the division (10) is designed as a radial division (10) of the stator core (3) and has a radially outer stator core area (11a) and a radially inner stator core area (11b) in the stator core (3), which contain the respective lines (22) for the introduction (E) or the return line (R) of the coolant flow (KS).
  5. Stator (1) after Claim 3 , characterized in that the division (10) is designed as a tangential division (10) of the stator core (3) and has a first and a second tangential stator core area (11a, b) containing the respective lines (22) for the introduction (E) and return (R) of the coolant flow (KS).
  6. Stator (1) according to one of the preceding claims, characterized in that a diversion (23) for the coolant flow is provided at the second axial end (6), wherein the diversion (23) is provided in particular in a cover (13) arranged on a winding head (12) arranged at the second axial end (6) and the diversion (23) is fluidically connected to the respective lines (22) of the first stator core area (11a) and the second stator core area (11b).
  7. Stator (1) according to one of the preceding claims, characterized in that a support device (14) is provided which is arranged axially offset to the stator core (3) and which is designed to engage positively with the winding (4) at the first axial end (5), wherein the respective lines (22) open into a first region (15a) or a second region (15b) of the support device (14) which is substantially liquid-tight separated from it, and wherein an introduction (E) of the coolant flow (KS) from the first region (15a) and a return line (R) of the coolant flow (KS) into the second region (15b) is provided, wherein a radial or tangential separation of the first and second regions (15a, b) is provided.
  8. Stator (1) according to one of the preceding claims, characterized in that the stator core (3) contains a stator lamination stack (26) with stator slots (7) extending in accordance with a winding path and each having the widened slot base (9), wherein the stator laminations of the stator lamination stack (26) with recesses (27) provided for forming the stator slots (7) are each identical and/or wherein the orientation of the stator slots (7) and the conductors (22) is adjustable by means of a stacking of the stator laminations rotated relative to each other.
  9. Stator (1) after Claim 8 , characterized in that the stator lamination stack (26) comprises an inner sub-stack (31) with radially inner stator slots (7) having the widened slot base (9) and an outer sub-stack (32) with radially outer stator slots (7) having the widened slot base (9), wherein the stator laminations of the inner sub-stack (31) and the stator laminations of the outer sub-stack (32) are designed with the same geometry and/or wherein the stator laminations of the inner sub-stack (31) and the stator laminations of the outer sub-stack (32) are stacked twisted in opposite directions, or the stator laminations with recesses (27) provided for forming the stator slots (7) having a widened slot base (9) are designed differently, wherein the course of the stator slots (7) and lines (22) is adjustable by means of different distances between the recesses (27) in the individual stator laminations.
  10. Stator (1) according to one of the preceding claims, characterized in that the stator core (3) has a substantially but not completely liquid-tight seal (16) connecting the stator lamination stack (26) with a baking varnish and/or a coating, in particular a coating providing insulation of the stator lamination stack (26) or an encapsulation with a sealing material.
  11. Stator (1) according to one of the preceding claims, characterized in that a coolant of the coolant stream (KS) is selected from the group consisting of or comprising: oil, water, water-glycol mixture, synthetic coolant or mixtures thereof.
  12. Radial flux twin-rotor machine, in particular for a wheel hub drive, comprising: a mechanically fixed base (17); a stator (1) according to one of the preceding claims, in which the stator (1) is positively connected to the base (17) or to a support device (14) supported on the base (17) for torque support; a twin rotor (30) with a first rotor (18) arranged radially inside the stator core (3); and a second rotor (19) arranged radially outside the stator core (3), in which an introduction (E) and a return (R) of a coolant flow (KS) into the stator core (3) is provided via the base (17) and/or the support device (14).
  13. Radial flux double rotor machine according to Claim 12 , characterized in that the respective lines (22) open into a first or a second outlet area (20a, b) of the base (17) which is substantially liquid-tight, and an introduction (E) of the coolant flow (KS) from the first outlet area (20a) and a return line (R) of the coolant flow into the second outlet area (20b) is provided, wherein a radial or tangential separation of the first from the second outlet area (20a, b) is provided.
  14. Radial flux double-rotor machine according to one of the Claims 12 or 13 , characterized in that the flow-through cooling device (2) of the stator (1) is fluidically connected to a cooling device of the radial flow twin-rotor machine and/or the base (17) has a cooling body (24) which is designed to absorb heat dissipated from the stator (1), in particular from the winding (4), via the flow-through cooling device (2).
  15. Radial flux double-rotor machine according to one of the Claims 12 until 14 , characterized in that at least the first rotor (18) arranged radially outside the stator core (3) has at least one leakage discharge opening (21), preferably several leakage discharge openings (21), for coolant escaping through the lamination boundaries of the stator lamination stack (26) and/or at the winding head (12).
  16. Wheel hub drive with a radial flux double rotor machine according to one of the Claims 12 until 15 .

Description

AREA OF INVENTION The present invention relates to a stator for a radial flux twin-rotor machine, in particular for a wheel hub motor. The invention further relates to a radial flux twin-rotor machine, in particular for a wheel hub drive with such a stator. TECHNICAL BACKGROUND Electric machines with a stator and up to two rotationally fixed rotors, so-called radial flux rotor machines or radial flux double rotor machines (also referred to simply as double rotor, multiple rotor, or dual rotor), are suitable for increasing both the torque density and the efficiency of electric drives compared to conventional electric machines. Particularly in wheel hub drives, such radial flux rotor machines offer decisive advantages in terms of achievable efficiency and the required installation space in the vehicle. An example of a radial flux double-rotor machine is in the DE 10 2021 003 942 A1 This type of radial flux twin-rotor machine is characterized by high torque and power density. Radial flux twin-rotor machines utilize established and mass-producible manufacturing processes for the winding and stator core, enabling the support of the torque generated in the stator core. Cooling the components of an electric drive machine is crucial for its efficiency. Stators of conventional electric machines are typically equipped with water or oil cooling, as these offer better thermal performance than air cooling. Cooling is achieved, for example, by cooling the stator shell, the rotor shaft, or the winding end. Coolant is supplied and discharged axially through the electric machine or the machine parts to be cooled. Cooling systems are also known in which a coolant flow is supplied to the stator via a first axial end and, after passing through channels provided in the stator, is discharged at the axially opposite end of the stator along with the heat transferred to the coolant. In twin-rotor machines, such a coolant flow cannot be implemented because the twin rotors cover the axial end of the stator that is not used for torque support. Therefore, cooling has so far been achieved by one-sided conductive cooling via the conductors, the support element that holds the conductor ends, and an associated coolant channel. SUMMARY OF THE INVENTION Against this background, the present invention is based on the objective of providing a stator for a radial flux twin-rotor machine which offers improved cooling performance and has a cooling system already integrated into the stator during manufacturing. According to the invention, this problem is solved by a stator with the features of claim 1 and/or a radial flux double rotor machine with the features of claim 12. Accordingly, the following is planned: - A stator for a radial flux twin-rotor machine, in particular for a wheel hub motor, comprising a stator core with a flow-through cooling device for cooling the stator; a winding placed in the stator core, which is designed to be self-supporting for torque support of the stator and projects beyond the stator core at a first axial end and a second axial end arranged opposite the first axial end; wherein torque support of the winding is provided at the first axial end, and the stator core contains stator slots extending in accordance with a winding path for arranging a single conductor bar of the winding, wherein the stator slots have a groove base located in the stator core, which has a widening relative to the stator slot and forms a channel for an axial coolant flow of the flow-through cooling device. - A radial flux twin-rotor machine, in particular for a wheel hub drive, with a mechanically fixed base and a stator according to the invention, wherein the stator is positively connected to the base or a support device supported on the base for torque support; a twin rotor with a first rotor arranged radially inside the stator core; and a second rotor arranged radially outside the stator core, wherein an introduction and a return of the coolant flow into the stator core is provided via the base and/or the support device. - A wheel hub drive with a radial flux double rotor machine according to the invention. The insight underlying the present invention is that in radial flux- Twin-rotor machines require improved cooling due to the higher continuous currents through the conductors in order to achieve higher continuous torques and power outputs. Improved cooling can be achieved by increasing the cooling surface area. The underlying idea of the present invention is to widen the base of the slots in the stator core of some or all of the slots in which the conductor bars of the windings are arranged, and to use the widened area of the stator slot, i.e., the slot base widened relative to the stator slot, as a conduit for the coolant. By widening the base of some or all of the stator slots located in the stator yoke, the magnetically unused part of the stator can be used for cooling. This results in improved thermal performance and a reduction in in