Tribology International, Vol. 81, pp 291-299, January 2015

Failure Mechanisms of Ball Bearings under Lightly Loaded, Non-Accelerated Usage Conditions

Hyunseok Oh, Michael H.Azarian, Carlos Morillo, Michael Pecht and Edward Rhemb

Center for Advanced Life Cycle Engineering (CALCE), University of Maryland, College Park, MD 20740, USA

Dell Inc., One Dell Way, Round Rock, TX 78682, USA


This paper identifies the failure mechanisms of ball bearings in low-power motors for electronics cooling. This study contrasts with previous studies on bearing life in its precipitation of failures under lightly loaded, non-accelerated usage conditions that are more representative of electronics cooling applications. Life tests were conducted on bearings composed of steel balls, steel inner and outer races, and a glass-fibre reinforced poly amide cage. Failure analysis of the ball bearings indicated that lubricant loss, transfer film formation, and wear particle generation were the failure mechanisms. Severe wear was found in the glass-fibre reinforced poly amide cages after failure. Several features extracted from the acoustic emission signals were identified as indicators of bearing degradation.

Keywords Rolling element bearings; Grease; Wear; Acoustic emission

Complete article is available from the Publisher and to the CALCE Consortium Members.

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