IMPACT OF SYSTEM-LEVEL FACTORS ON PLANETARY GEAR SET BEHAVIOR

ABSTRACT
Planetary gear sets are used commonly in many diverse product applications. Their
compact and co-axial design and ratio flexibility make them preferable to counter-shaft gear
drives. Planetary gear sets are complex, multi-mesh systems formed by multiple branches of
planet gears that are in mesh with a sun gear and a ring gear and are held by a common carrier
through needle bearings and planet pins. Their design presents unique challenges stemming from
a number of system-level issues, including their planet load sharing behavior, dynamic response,
rim deflections, and spline/support conditions. This study investigates the influence of severalsystem
level factors on gear stresses, and quantifies their impact on the resultant bending fatigue
lives of the gears in planetary gear sets.

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