Accession Number : AD0437467


Title :   AN EXPERIMENTAL INVESTIGATION OF THE FATIGUE LIFE AND LIMIT LOAD CHARACTERISTICS OF NEEDLE ROLLER BEARINGS UNDER OSCILLATING LOAD CONDITIONS.


Descriptive Note : Rept. for Mar 56-Sep 63,


Corporate Author : FRANKLIN INST PHILADELPHIA PA LABS FOR RESEARCH AND DEVELOPMENT


Personal Author(s) : Tawresey,J S ; Shugarts,W W ,Jr


Report Date : Mar 1964


Pagination or Media Count : 153


Abstract : This investigation was made to determine, by test of full scale bearings, the factors influencing life of a bearing in cyclic oscillation, as encountered in helicopter rotor hinges. A field survey was made to guide selection of an appropriate size and type of bearing for test and establish the principal operating variables. A machine was designed, a prototype unit was built and tested, followed by the construction of seven additional machines. Four test bearings were run simultaneously in each machine, under essentially identical conditions. Each test bearing was subjected to fixed conditions of load, speed, amplitude of oscillation, and lubrication. It was run continuously until evidence developed of incipient failure in the form of spalling or flaking breakout of the raceways. The elapsed time in test prior to failure, marks the life of the bearing. The well known and characteristic deviation of individual bearing lives, within a group of bearings, was evident in all test runs. Approximately 750 bearings were tested in 25 different test runs, comprising a systematic combination of operating variables. (Author)


Descriptors :   FATIGUE(MECHANICS) , HELICOPTER ROTORS , LUBRICATION , LOADS(FORCES) , LIFE EXPECTANCY(SERVICE LIFE) , INSTRUMENTATION , PERFORMANCE(ENGINEERING) , GREASES , OILS , FAILURE(MECHANICS) , MONITORS , TORQUE , HYDRAULIC EQUIPMENT


Distribution Statement : APPROVED FOR PUBLIC RELEASE