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A Dynamic Load Distribution Model of Planetary Gear Sets

Ryali, Lokaditya
http://orcid.org/0000-0003-1524-6276
http://rave.ohiolink.edu/etdc/view?acc_num=osu1638411883596124

Abstract Details

2021, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
Planetary gearsets are indispensable power transfer components in several mechanical systems and are preferred over counter-shaft gears due to their coaxial arrangement, high power density, minimal radial loads, and multiple possible kinematic combinations. In spite of their several benefits and widespread use, the complex arrangement of components in a planetary gear system makes them susceptible to noise and vibration issues. Analysis and design tools specific to planetary gear sets are sparse, accurate models that are available for detailed analyses of planetary gear sets require significant computational effort and expert users. In contrast, the computationally efficient lumped parameter models available in the literature are not very effective for root cause analysis because of the simplifications made in modeling the gear meshes. These challenges become multifold with the advent of electric drive units, not only due to their high operating loads and speeds but also due to the fact that there is no broadband noise from the engine to mask the transmission noise. Considering the aforementioned challenges with planetary gear design and lack of accurate and computationally efficient analysis tools, this dissertation presents a three-dimensional dynamic load distribution model for planetary gearsets. The proposed formulation uses a numerical integration scheme in conjunction with an iterative elastic contact algorithm to solve the multibody contact problem, and unlike previous models, can implicitly capture the influence of probable assembly and manufacturing errors in a planetary gear set. The developed dynamic load distribution model for planetary gears builds upon the quasi-static model of Hu et al. as its basis. Therefore to build trust in the fundamental framework, tightly controlled quasi-static planetary gear experiments were conducted to thoroughly validate the quasi-static model before developing the dynamic model. A unique experimental methodology, that synchronously measures various quasi-static responses of a planetary gear set, namely planet load sharing, overall transmission error, and floating sun gear orbits, was developed. The influence of various design parameters and operating conditions such as planet mesh phasing, carrier pin position errors, gear tooth modifications, and input torque on the system’s response were investigated, and finally, these experimental results were accurately captured by theory using the static planetary load distribution model. The baseline dynamic model considered all the bodies in the system to be rigid, with elastic flexibility considered only at the gear teeth. This model was used to substantially study the effect of various system parameters on the dynamic characteristics of planetary gear sets. In view of powertrain components being continually optimized to their design limits, the baseline dynamic model is further extended to account for additional compliances in the system. Finite element based models are used to capture the influence of input/output shaft, carrier, planet pin, and ring gear flexibilities on the response of the planetary gear system. Owing to its computational efficiency and fidelity, the developed dynamic model has immense industrial viability and can be used both as a design and an analysis tool. It can also be used to conduct parametric studies to explore the effects of various component and system level design parameters on the dynamic response of gearset.
David Talbot (Advisor)
Ahmet Kahraman (Committee Member)
Carlos Castro (Committee Member)
Manoj Srinivasan (Committee Member)
355 p.
Aerospace Engineering; Mechanical Engineering
Gears, Planetary Gear Sets, Dynamic Load Distribution, Contact Mechanics

Recommended Citations

Citations

  • Ryali, L. (2021). A Dynamic Load Distribution Model of Planetary Gear Sets [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1638411883596124

    APA Style (7th edition)

  • Ryali, Lokaditya. A Dynamic Load Distribution Model of Planetary Gear Sets. 2021. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1638411883596124.

    MLA Style (8th edition)

  • Ryali, Lokaditya. "A Dynamic Load Distribution Model of Planetary Gear Sets." Doctoral dissertation, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1638411883596124

    Chicago Manual of Style (17th edition)

osu1638411883596124
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This open access ETD is published by The Ohio State University and OhioLINK.