Accession Number : ADA119165

Title :   Reliability Model for Planetary Gear Trains.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CENTER

Personal Author(s) : Savage,Michael ; Paridon,Charles A ; Coy,John J

PDF Url : ADA119165

Report Date : Jan 1982

Pagination or Media Count : 23

Abstract : A reliability model is presented for planetary gear trains in which the ring gear is fixed, the sun gear is the input, and the planet arm is the output. The input and output shafts are co-axial and the input and output torques are assumed to be co-axial with these shafts. Thrust and side loading are neglected. This type of gear train is commonly used in main rotor transmissions for helicopters and in other applications which require high reductions in speed. The reliability model is based on the Weibull distribution of the individual reliabilities of the transmission components. The transmission's basic dynamic capacity is defined as the input torque which may be applied for one-million input rotations of the sun gear. Load and life are related by a power law. The load-life exponent and basic dynamic capacity are developed as functions of the component capacities. (Author)

Descriptors :   *Gears, *Transmissions(Mechanical), *Helicopter rotors, *Shafts(Machine elements), *Reliability, *Mathematical models, Survival(General), Statistical distributions, Weibull density functions, Input, Output, Torque, Rings, Bearings

Subject Categories : Helicopters
      Statistics and Probability
      Machinery and Tools

Distribution Statement : APPROVED FOR PUBLIC RELEASE