Setting bearing preload utilizing thermal exspansion/contraction

Abstract

Bearings in a motor or bearing cartridge are positioned relative to the shaft and an outer sleeve, and a bearing retainer is then pressed against the outer races of one of the bearings in order to hold the bearings in position and preload the bearings in a desired orientation. The bearing retainer is chilled to a temperature significantly different than the sleeve with which it cooperates; shrinking the retainer to a size where it may be slip fit within a sleeve or other means for supporting the bearings in place. The retainer is then pressed against the outer races of the bearings, and held in place while it returns to the temperature of the sleeve within which it is fit. In this way, the preload is defined and maintained for the long term, as the retainer is pressed tightly against the outer race of the bearings; and the retainer is held within the sleeve as it returns to the same temperature being chilled is eliminated. In an alternative approach, the retainer ring may be heated to expand its internal diameter, and after being heated to a temperature which is greater than the sleeve, is slipped over the outside of the sleeve while the bearings are being held with the required preload.