Modeling, Modal Properties, and Mesh Stiffness Variation Instabilities of Planetary Gears

Planetary gear noise and vibration are primary concerns in their applications in helicopters, automobiles, aircraft engines, heavy machinery, and marine vehicles. Dynamic analysis is essential to the noise and vibration reduction. This work analytically investigates some critical issues and advances the understanding of planetary gear dynamics. A lumped-parameter model is built for the dynamic analysis of general planetary gears. The unique properties of the natural frequency spectra and vibration modes are rigorously characterized. These special structures apply for general planetary gears with cyclic symmetry and, in practically important case, systems with diametrically opposed planets. The special vibration properties are useful for subsequent research. Taking advantage of the derived modal properties, the natural frequency and vibration mode sensitivities to design parameters are investigated. The key parameters include mesh stiffnesses, support/bearing stiffnesses, component masses, moments of inertia, and operating speed. The eigensensitivities are expressed in simple, closed-form formulae associated with modal strain and kinetic energies. As disorders (e.g., mesh stiffness variation, manufacturing and assembling errors) disturb the cyclic symmetry of planetary gears. their effects on the free vibration properties are quantitatively examined. Well-defined veering rules are derived to identify dramatic changes of natural frequencies and vibration modes under parameter variations. The knowledge of free vibration properties, eigensensitivities and veering rules provide important information to effectively tune the natural frequencies and optimize structural design to minimize noise and vibration. Parametric instabilities excited by mesh stiffness variations are analytically studied for multi-mesh gear systems. The discrepancies of previous studies on parametric instability of two-stage gear chains are clarified using perturbation and numerical methods.

  • Record URL:
  • Corporate Authors:

    Ohio State University, Columbus

    Department of Mechanical Engineering
    Columbus, OH  United States  43210

    National Aeronautics and Space Administration

    400 Maryland Avenue, SW
    Washington, DC  United States  20546

    Army Research Laboratory

    Aberdeen Proving Ground, MD  United States  21001
  • Authors:
    • Parker, Robert G
    • Lin, Jian
  • Publication Date: 2001-5


  • English

Media Info

  • Media Type: Web
  • Edition: Final Contractor Report
  • Features: Appendices; Bibliography; Figures; Tables;
  • Pagination: 121p

Subject/Index Terms

Filing Info

  • Accession Number: 01104336
  • Record Type: Publication
  • Report/Paper Numbers: NASA CR--2001-210939, ARL-CR-462
  • Contract Numbers: NAG3-1979
  • Files: NTL, TRIS
  • Created Date: Jul 2 2008 1:43PM