Abstract: A wheel-hub motor (100) comprises a rotor (14) having permanent magnets, although other field generation means are available, and a stator (12). The stator has coils (22) wound on stator bars (16) for interaction with the magnetic field of the rotor across an air gap (26a,b) defined between them. The stator (12) forms a housing of a chamber (70) containing refrigerant (82). The stator housing has heat dissipating fins (96) accessible by the open environment whereby air movement relative to the housing caused at least by rotation of the rotor absorbs heat from the fins. The motor may be an axial flux machine, the coils being wound on bars that are disposed circumferentially spaced around a rotation axis (80) of the rotor. The wheel of the vehicle is mounted directly on the rotor housing.

Abstract: An electric machine (10) comprises a rotor (14a, b) having permanent magnets (24a, b) and a stator (12) having coils (22) wound on stator bars (16) for interaction with the magnets across an air gap (26a, b) defined between them. The bars (16) and coils (22) are enclosed by an annular stator housing (42a, b) that extends between the air gap. A chamber (52, 54, 56) is defined that incorporates cooling medium to cool the coils. The stator housing comprises two mating clamshells (42a, b) that mount the stator bars and coils in the machine. Each clamshell is moulded from reinforced plastics and interconnected (optionally through one or more intermediate components).