Accession Number : ADA257375
Title : Dynamics of a Split Torque Helicopter Transmission
Descriptive Note : Technical memo.
Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CENTER
Personal Author(s) : Rashidi, Majid ; Krantz, Timothy
Report Date : Jan 1992
Pagination or Media Count : 14
Abstract : A high reduction ratio split torque gear train has been proposed as an alternative to a planetary configuration for the final stage of a helicopter transmission. A split torque design allows a high ratio of power-to-weight for the transmission. The design studied in this work includes a pivoting beam that acts to balance thrust loads produced by the helical gear meshes in each of two parallel power paths. When the thrust loads are balanced, the torque is split evenly. A mathematical model was developed to study the dynamics of the system. The effects of time varying gear mesh stiffness, static transmission errors, and flexible bearing supports are included in the model. The model was demonstrated with a test case. Results show that although the gearbox has a symmetric configuration, the simulated dynamic behavior of the first and second compound gears are not the same. Also, results show that shaft location and mesh stiffness tuning are significant design parameters that influence the motions of the system. Split torque gearbox; Gear dynamics; Load sharing; Transmission error.
Descriptors : *HELICOPTERS , *TRANSMISSION GEARS , *TORQUE , TEST AND EVALUATION , MATHEMATICAL MODELS , RATIOS , MODELS , DYNAMICS , PARAMETERS , STIFFNESS , ERRORS , TRANSMISSIONS(MECHANICAL) , GEARS , THRUST , STATICS , BEARINGS , BEHAVIOR , POWER , TUNING , BALANCE , CONFIGURATIONS , PATHS , MOTION , MESH , REDUCTION , TIME , SHARING
Subject Categories : Helicopters
Distribution Statement : APPROVED FOR PUBLIC RELEASE