Search

JP-2026514489-A - Electric motor with cooling system

JP2026514489AJP 2026514489 AJP2026514489 AJP 2026514489AJP-2026514489-A

Abstract

An electric motor (1) comprising a stator (3), a rotor (2), a housing (20), a cooling system (4), and a motor drive system comprising a circuit board (6) and a plurality of power semiconductors (12), wherein the housing (20) comprises a stator housing section (21) including a peripheral wall (22a) surrounding the stator (3), and a drive system housing section (25) including a base wall (26) located at the axial end of the stator housing section (21), and the circuit board (6) mounted on the base wall (26). The cooling system comprises a cooling channel (9) for circulating a coolant, the cooling channel being bounded by a wall portion including part of the peripheral wall (22a) and part of the base wall (26), and configured such that the liquid in the cooling channel cools both the stator and the motor drive system simultaneously.

Inventors

  • メレル・セドリック

Assignees

  • ソンスボ モーション ボンクール エスア

Dates

Publication Date
20260511
Application Date
20240419
Priority Date
20230424

Claims (11)

  1. An electric motor (1) comprising a stator (3), a rotor (2), a housing (20), a cooling system (4), a motor drive system including a circuit board (6) and a plurality of power semiconductors (12), wherein the housing (20) comprises a stator housing section (21) surrounding the stator (3) and a drive system housing section (25) including a base wall (26), the circuit board (6) mounted on the base wall (26), and the stator housing section (21) and the drive system housing section (25) are separate components assembled and fixed together. An electric motor characterized in that the stator housing section (21) includes an inner circumferential wall (22a) and an outer circumferential wall (22b), the inner circumferential wall being joined to the outer circumferential wall at a first axial end (37a), both the inner circumferential wall and the outer circumferential wall extending from the first axial end to an assembly interface at a second axial end (37b), and the cooling system includes a cooling channel (9) for flowing a coolant through, the cooling channel being formed and bounded between the inner circumferential wall (22a), the outer circumferential wall (22b), and the base wall (26), and the fluid in the cooling channel being configured to cool both the stator and the motor drive system simultaneously.
  2. The electric motor according to claim 1, wherein seals (33a, 33b) are fitted within the assembly interface between the stator housing section and the base wall, and the base wall (26) is assembled in a sealed state in contact with the second axial ends of the inner and outer circumferential walls.
  3. The electric motor according to claim 1 or 2, wherein the cooling system (4) includes a single inlet (31) for the flow of the coolant to enter the cooling channel and a single outlet (32) for the flow of the coolant to exit the cooling channel.
  4. The electric motor according to claim 1, wherein the cooling channel (9) completely encloses the stator, except for the separation wall (34a, 34b) between the inlet (31) and the outlet (32).
  5. The electric motor according to claim 4, wherein the separation wall (34a, 34b) between the inlet (31) and the outlet (32) has a small tolerance gap (34c) configured such that less than 5% of the overall coolant flow leaks directly across the separation wall from the inlet to the outlet.
  6. The electric motor according to claim 1, wherein the plurality of power semiconductors (12) are mounted on the circuit board in a position that overlaps the cooling channel in the axial direction.
  7. The electric motor according to claim 1, wherein the base wall (26) of the drive system housing section (25) includes at least one heat transfer reinforcing structure (35), such as a rib, fin, support, projection, groove, or recess, within the cooling channel (9).
  8. The electric motor according to claim 1, wherein the cooling channel (9) has an axial portion (9a) and a radial portion (9b), the axial portion extending along the circumferential wall (22a), the radial portion extending on the base wall (26), and the axial portion (9a) overlapping the stator (3) for a length (a1) exceeding 50% of the axial length (a2) of the stator.
  9. The electric motor according to claim 8, wherein the axial portion (9a) and the radial portion (9b) of the cooling channel together form a single non-constricted channel.
  10. The electric motor according to claim 8 or 9, wherein the axial portion (9a) and the radial portion (9b) of the cooling channel form a constricted portion that is fluidly interconnected by a restricted fluid interconnection passage (9c).
  11. The electric motor according to claim 1, wherein the stator housing section (21) is a single, integrally molded part.

Description

This invention relates to an electric motor equipped with a cooling system. It is well known in the art that some components of powerful electric motors generate heat during operation, and cooling is often necessary to avoid damage due to overheating. For example, the power semiconductors of the stator and inverter are often cooled in powerful electric motors. For instance, metal-oxide-semiconductor field-effect transistors can be used as power semiconductors in inverters. In some motors, the electronics necessary to operate the motor, including the inverter, are integrated into the motor itself. In some prior art solutions, the stator and power electronics are cooled by two separate, independent cooling circuits. In other prior art solutions, the stator and power electronics are cooled by a single cooling circuit with a relatively complex path through the motor housing. This is a perspective view of an electric motor according to a first embodiment of the present invention.This is a perspective view of the disassembled assembly of the base portion of the stator housing and the motor drive system housing of an electric motor according to a first embodiment of the present invention.This is a perspective view of the disassembled assembly of the base portion of the stator housing and the motor drive system housing of an electric motor according to a first embodiment of the present invention.This is a cross-sectional view of an electric motor according to a first embodiment of the present invention.This is a perspective cross-sectional view of a part of an electric motor according to a first embodiment of the present invention.This is a perspective view of a motor drive system housing for an electric motor according to a first embodiment of the present invention.This is a perspective view of a motor drive system housing for an electric motor according to a modified example of the first embodiment of the present invention.This is a perspective view of the stator and stator housing of an electric motor according to a first embodiment of the present invention.This is a perspective view of an electric motor according to a second embodiment of the present invention.This is a perspective cross-sectional view of an electric motor according to a second embodiment of the present invention. Referring to the drawings, the electric motor 1 according to an embodiment of the present invention includes a rotor 2, a stator 3, a motor drive system, and a housing 20 in which the rotor, stator, and motor drive system are mounted. The electric motor 1 further includes a cooling system 4, which includes a cooling channel 9 formed within the housing 20, where a coolant is received into the cooling channel and flows through it. The motor drive system includes a circuit board 6 and electronic components mounted on the circuit board, including at least one inverter containing a power semiconductor 12. The inverter supplies drive current to the electrical phase of the electric motor; thus, a motor with multiple phases has multiple corresponding inverters. The power semiconductors of the inverter can take the form of bipolar transistors, insulated-gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs) based on materials such as Si, SiC, or GaN, which are well-known in the field of electric motor inverters, or high-electron-mobility transistors (HEMTs) based on materials such as GaN. In certain embodiments, the electric motor 1 can be a high-voltage electric motor with a nominal DC voltage exceeding 850V, particularly exceeding 1000V, and especially exceeding 1500V. The housing 20 includes a stator housing section 21 that houses the stator 3, and a drive system housing section 25 that houses a circuit board 6 containing electronic components of the motor drive system, including power semiconductors 12. The drive system housing section 25 is advantageously positioned at the axial end of the stator housing section 21, thereby positioning the circuit board 6 of the motor drive system adjacent to the axial end of the stator 3, where axial is defined herein as the direction of the rotation axis of the rotor 2. Mounting the motor drive system on the axial end of the stator 3 advantageously results in a compact configuration and allows for efficient cooling of both the stator and the electronic components of the motor drive system, as will be described in more detail below. The stator housing section 21 includes an inner circumferential wall 22a that surrounds and contacts the stator 3. This inner circumferential wall also forms the boundary of the cooling channel 9 on the side opposite to the side in contact with the stator. Heat generated in the stator is primarily dissipated into the cooling fluid flowing through the cooling channel by conduction via the inner circumferential wall 22a. The inner circumferential wall 22a continues to an end wall 23 via a bend, and the axial end of the stator 3 is located