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Effects of Planetary Gear Ratio on Mean Service LifePlanetary gear transmissions are compact, high-power speed reductions which use parallel load paths. The range of possible reduction ratios is bounded from below and above by limits on the relative size of the planet gears. For a single plane transmission, the planet gear has no size at a ratio of two. As the ratio increases, so does the size of the planets relative to the sizes of the sun and ring. Which ratio is best for a planetary reduction can be resolved by studying a series of optimal designs. In this series, each design is obtained by maximizing the service life for a planetary with a fixed size, gear ratio, input speed power and materials. The planetary gear reduction service life is modeled as a function of the two-parameter Weibull distributed service lives of the bearings and gears in the reduction. Planet bearing life strongly influences the optimal reduction lives which point to an optimal planetary reduction ratio in the neighborhood of four to five.
Document ID
Document Type
Conference Paper
Savage, M. (Akron Univ. Akron, OH United States)
Rubadeux, K. L. (Hendrickson Co. Canton, OH United States)
Coe, H. H. (Army Research Lab. Cleveland, OH United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1996
Subject Category
Structural Mechanics
Report/Patent Number
NAS 1.15:107275
Meeting Information
Power Transmission and Gearing(San Diego, CA)
Funding Number(s)
OTHER: 505-62-36
PROJECT: DA Proj. 1L1-62211-A-47A
Distribution Limits
Work of the US Gov. Public Use Permitted.

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NameType 19970018785.pdf STI