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Effect of Silicon Nitride Balls and Rollers on Rolling Bearing LifeThree decades have passed since the introduction of silicon nitride rollers and balls into conventional rolling-element bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel bearings. Life factors were determined and reported for hybrid bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and cylindrical roller hybrid bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid bearings are predicted to have a lower fatigue life than all-steel bearings by 58 percent for deep-groove bearings, 41 percent for angular-contact bearings, and 28 percent for cylindrical roller bearings.
Document ID
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Zaretsky, Erwin V.
(NASA Glenn Research Center Cleveland, OH, United States)
Vlcek, Brian L.
(University of Southern Georgia Statesboro, GA, United States)
Hendricks, Robert C.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
September 7, 2013
Publication Date
April 1, 2005
Subject Category
Structural Mechanics
Report/Patent Number
Meeting Information
Meeting: 2004 International Joint Tribology Conference
Location: Long Beach, CA
Country: United States
Start Date: October 24, 2004
End Date: October 27, 2004
Sponsors: Society of Tribologists and Lubrication Engineers, American Society of Mechanical Engineers
Funding Number(s)
WBS: WBS 22-714-09-16
Distribution Limits
Work of the US Gov. Public Use Permitted.
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