COOLING STRUCTURE OF DYNAMO-ELECTRIC MACHINE

摘要

In order to provide the cooling structure of a dynamo-electric machine in which cooling efficiency of a rotor is enhanced, linear protrusions protruding radially inward and extending in the axial direction are provided tightly on the inner circumferential surface of the coolant passage of a rotor shaft. The protrusions are a plurality of rod members supported at the opposite ends tehreof by two ring members press fitted to the inner circumferential surface of the coolant passage. The protrusion has a height equal to 10-15% of the inside diameter of the coolant passage. In the coolant passage, a disc having an orifice of inside diameter dimension equal to 20-40% of the inside diameter of the coolant passage may be provided in order to generate turbulence of coolant. The orifice is arranged coaxially, eccentrically, or obliquely with respect to the coolant passage or arranged in combination of those arrangements. Protrusions not only increase the contact area between the fluid and the inner circumferential surface of the shaft but also induce turbulence of coolant flow in the shaft, whereby heat transmission from the shaft to the coolant is increased and cooling effect of the rotor is enhanced.