Patent ID: 8803396

Claim:
A rotor assembly mounted to rotate around an axis of rotation (X-X′) and comprising: two magnet wheels ( 10 ) separated by an axial spacing and arranged opposite each other, each of the wheels ( 10 ) comprising an end shield ( 11 ) substantially perpendicular to the axis (X-X′) and claws ( 12 ) extending axially from the end shield ( 11 ) towards the other wheel ( 10 ); the end shield ( 11 ) of one of the magnet wheels comprising an axial face ( 111 ) opposite the other wheel; the claws ( 12 ) of one wheel ( 10 ) being attached to the end shield ( 11 ) by respective bases ( 121 ) mutually separated by peripheral spaces ( 13 ); and a fan ( 30 ) positioned on the axial face ( 111 ) of the end shield ( 11 ) of one of the wheels ( 10 ) opposite the other wheel ( 10 ) so as to axially seal at least partly one of the peripheral spaces ( 13 ); the fan ( 30 ) comprising a plate ( 31 ) substantially perpendicular to the axis (X-X′) and attached to the end shield ( 11 ), and blades ( 32 ) protruding from the plate ( 31 ); the plate ( 31 ) having a sealing part ( 311 ) axially sealing at least one of the peripheral spaces ( 13 ); the plate ( 31 ) of the fan ( 30 ) comprising a substantially annular solid part ( 312 ) having a radially outer edge; the sealing part ( 311 ) comprising an axial relief ( 314 ) in the form of a thin tab comprising a first face ( 315 ) axially inclined from the solid part ( 312 ) of the plate ( 31 ) at the side of the claws ( 12 ) and from the axis of rotation (X-X′) so that the first face ( 315 ) extending obliquely between the solid part ( 312 ) and the axis of rotation (X-X′); the tab further comprising a second face ( 316 ) extending from a distal end of the first face ( 315 ) parallel to the axis (X-X′); the axial relief ( 314 ) extending from the plate ( 31 ) between the claws ( 12 ); the claws ( 12 ) having radially outer surfaces ( 123 ) defining a diameter of the rotor assembly; the second face ( 316 ) of the tab ( 314 ) lying in the extension of the outer faces ( 123 ) of two claws ( 12 ) and partially sealing the space separating these two outer faces over a short axial length; the solid part ( 312 ) is provided with recessed zones ( 318 ) hollowed radially inwardly from the radially outer edge of the solid part ( 312 ), each of the recessed zones ( 318 ) being delimited by a base and two lateral sides diverging from the base up to the radially outer edge of the solid part ( 312 ); the sealing part ( 311 ) extending from the base of the recessed zone ( 318 ).