A flywheel/motor assembly is disclosed that comprises a motor housing having a sidewall and an end wall extending substantially perpendicularly from the sidewall. The end wall enclose a motor assembly having a rotatable shaft extending therefrom. The motor housing has at least one air flow opening therethrough. A flywheel is coupled to the shaft, and includes a pulley side and a motor side opposite the pulley side, wherein the motor side is aligned substantially with the end wall and does not extend over the sidewall. A plurality of vanes are associated with the flywheel, wherein adjacent vanes form channels therebetween. A ring is coupled to the plurality of vanes and at least partially encloses the channels and forms exhaust ports away from the shaft. Rotation of the flywheel draws air through the motor housing's openings into the channels and out the exhaust ports. The pulley side may include balancing bores for receiving balancing material to balance the finished assembly. An angular interference fit between the flywheel and motor shaft may also assist in balancing the finished assembly. A ventilation fan system may also be connected to the shaft at an end opposite the flywheel.
An electric motor includes a rotor shaft arranged in a casing and having an axial hollow bore formed therethrough for passage of lubricating oil, a rotor, a stator, a pair of bearings each having an inner race and an outer race, a pair of bearing fixing parts supporting the rotation of the rotor shaft, and bearing cooling devices each having a cylindrical heat dissipation portion fixedly secured to the rotor shaft so as to be in contact with either one of end faces of the individual inner races, the heat dissipation portion extending from the one end face of each inner race to a side opposite to the bearings. A pair of spaces between rotor-side end faces of the bearings and the bearing fixing parts, respectively, are in communication with ring gaps between the heat dissipation portions and the rotor shaft, respectively, through radial communication holes in the rotor shaft.
