Methods of making dynamoelectric machine structures

Abstract

Shaft material of a given desired nominal diameter corresponding to a nominal desired shaft extension diameter for a particular motor is selected; shaft blanks are cut; optional operations such as chamfering and washing, grinding, machining of at least one flat and phosphatizing to inhibit rust are performed; a first accessory member is assembled in a predetermined position by heat shrinking; a rotor body is assembled with shaft; and a second accessory member is assembled by heat shrinking. For ball bearing applications, a person practicing the invention in one form may finish turn concentric journals on accessory members for the inner races of bearings after accessory members have been assembled with a shaft so that inner races of ball bearings may be lightly pressed onto the journals, and the rotor is assembled with end frames and stator. The concentric journals permit a press fit of ball bearings without substantially exceeding .0005 of an inch press fit and thus damage of the bearings is avoided. One preferred method includes stressing shaft portions and maintaining the stressed condition to increase stiffness of a rotor system and thereby increase the rotor system resonant frequency. Apparatus disclosed herein includes means for maintaining a desired perpendicular relationship between a shaft and various parts assembled therewith. Such apparatus assists in establishing desired dimensional relationships. In one exemplification, it is preferred to use aluminum collars that conform to a shaft surface and thus establish a more thorough and uniformly stressed condition of the shaft.