Low-Noise, High-Strength, Spiral-Bevel Gears for Helicopter Transmissions
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CENTER
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Improvements in spiral-bevel gear design were investigated to support the ArmyNASA Advanced Rotorcraft Transmission program. Program objectives were to reduce weight by 25 percent, reduce noise by 10 dB, and increase life to 5000 hr mean-time-between-removal. To help meet these goals, advanced-design spiral- bevel gears were tested in an OH-58D helicopter transmission using the NASA 500- hp Helicopter Transmission Test Stand. Three different gear designs tested included 1 the current design of the OH-58D transmission except gear material X-53 instead of AISI 9310, 2 a higher-strength design the same as the current but with a full fillet radius to reduce gear tooth bending stress and thus, weight, and 3 a lower-noise design the same as the high-strength but with modified tooth geometry to reduce transmission error and noise. Noise, vibration, and tooth strain tests were performed and significant gear stress and noise reductions were achieved.... TransmissionsMachine elements, Gears, Noise, Vibration, Strain measurement.