Patent ID: 6848831

Claim:
A support structure of a rotation shaft of a motor/generator connected to an external device, the rotation shaft having two ends, the structure comprising: a pair of bearings respectively fitted to the ends of the rotation shaft, each of the bearings having an end face perpendicular to the rotation shaft; a housing having bearing fitting parts that respectively support the bearings, the fitting parts allowing a displacement of the bearings in an axial direction of the rotation shaft; and a pair of pressurizing members each of which is disposed between the end face of each of the bearings and the housing, wherein the motor/generator is provided with a rotating body supported by the rotation shaft, the external device is an engine having a crankshaft connected to the rotation shaft, and the pressurizing member has a stiffness defined by a relation on resonance frequency of (Nei/60)×(N/2)≧(K/Mb) 1/2 , wherein K is a stiffness of one of the pressurizing members, Nei is an idle rotation speed of the engine, N is a number of cylinders of the engine, and Mb is a mass of the rotating body.