Electric machine—over-moulding construction

摘要

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 molded from reinforced plastics and interconnected (optionally through one or more intermediate components). At least one clamshell has over-molded therein stator bar shoes that form part of said radial wall, and optionally one or more of the following components: cylindrical boss supports extending along the cylindrical outer wall part; connection studs that communicate electrically the chamber externally; stator coils; coolant inlet and outlet ports; and an outer race of a rotor bearing.

主权项

1. An electric machine comprising a rotor having permanent magnets and a stator having coils wound on stator bars for interaction with the magnets across an air gap defined between them, the rotor being journalled for rotation with respect to the stator about a rotation axis wherein the bars and coils thereon are enclosed by an annular stator housing and wherein the stator housing comprises two mating clamshells that mount the stator bars and coils in the machine, each stator bar having shoes at each end and each clamshell having cylindrical wall parts on inner and outer radii and a radial wall joining the inner and outer cylindrical wall parts, whereby the two clamshells are connected together between facing edges of said inner and outer cylindrical wall parts to form said stator housing, and in which the clamshells define between them an annular chamber through which cooling medium can be circulated around the coils to cool them,
characterised in that each stator bar is formed from at least two bar parts interconnected at a transverse split across the section of the stator bar and in that each clamshell is injection moulded from reinforced plastics, being overmoulded around the shoes of one bar part of the stator bar to retain and position in the radial wall said bar parts whereby said shoes form part of said radial wall.