Patent ID: 8157544

Claim:
A motor-driven supercharger comprising: a turbine shaft having a turbine impeller in one end thereof; a compressor impeller rotationally driven by the turbine shaft; a bearing housing supporting the rotatable turbine shaft; a motor stator fixed within the bearing housing; and a motor rotor rotationally driven by the motor stator, wherein the motor stator has a stator iron core, a stator winding, and a mold member embedding the stator iron core and the stator winding therein and having a high coefficient of thermal conductivity, and further comprising an outer sleeve closely attached to an outer peripheral surface of the mold member and to an inner surface of the bearing housing, wherein the outer sleeve forms a liquid tight water cooling jacket, wherein the mold member has a hollow cylinder portion embedding the stator iron core therein, and a pair of radially outward extending collar portions respectively contacting both ends in an axial direction of the hollow cylinder portion, and embedding the stator winding therein, the outer sleeve includes a part that is sandwiched in the axial direction between the pair of radially outward extending collar portions, and that has a pair of outboard surfaces respectively contacting inner surfaces in the axial direction of the pair of the radially outward extending collar portions, each of the radially outward extending collar portions has a part positioned at the outer side of the hollow cylinder portion in a radial direction of the turbine shaft, the part of each of the radially outward extending collar portions has the inner surface extending in the axial direction of the radially outward extending collar portion.