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7.24.20.LoseyMSThesis.pdf (9.57 MB)

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Analysis of Magnetic Gear End-Effects to Increase Torque and Reduce Computation Time

Losey, Bradley
http://rave.ohiolink.edu/etdc/view?acc_num=osu1595514209192582

Abstract Details

2020, Master of Science, Ohio State University, Mechanical Engineering.
Magnetically geared machines perform gearing operations by utilizing magnetic force interactions between the rotors as opposed to mechanical force interactions. Many benefits of magnetic gears derive from the fact that there is no contact between the rotors. Contactless gearing allows for quieter operation, eliminates the need for lubrication outside the bearings, decreases the need for maintenance, and provides inherent overload protection. Another benefit is that the magnetic gear design lends itself to direct implementation in motors as opposed to having a separate mechanical gearbox. A magnetic gear has three fundamental components: a high speed rotor, a low speed rotor, and a flux modulator. These components work in tandem to generate magnetic field harmonics which scale the torque and speed of the input shaft. There are many magnetic gear designs that accomplish this task, but this thesis focuses on coaxial magnetic gears (CMGs) that utilize Halbach array magnet rotors and no back iron. In this design, the flux modulator is radially nested within the low and high speed rotors with the high speed rotor typically positioned at the inner most layer. Inherent to magnetic gear behavior is a 3D inefficiency known as end-effect loss. This loss causes flux to leak over the axial ends of the gear and back to its source. This flux never makes it to the flux modulator and never contributes to torque. End-effect losses can cause a significant decrease in output torque (10% to 40% depending on the design) and can only be modeled with large 3D simulations. The first aspect of this research involves the development of a reduced length modeling method which accounts for the axial variation of end-effect losses within the gear to shorten the computation time of magnetic gearing models. It has been shown for the models in this thesis that computation time can be cut in half while the torque results stay within 5% of their true value. Several magnetic gear design variables have been correlated to the severity of end-effect losses to guide general implementation of the modeling technique to CMGs. The second aspect involves the creation of a novel magnetic gear design for the purpose of mitigating end-effect losses. This cladding magnet-coaxial magnetic gear (CM-CMG) utilizes axially oriented magnets on the axial ends of the gear to mitigate flux leakage over the ends of the gear. It has been found that a CM-CMG can generate up to 12.4% more torque than an equally massive CMG design. Theory has been developed to guide the application of cladding magnets to general CMG designs.
Marcelo Dapino (Advisor)
Rebecca Dupaix (Committee Member)
167 p.
Mechanical Engineering
Magnetic Gears; End-Effects; Reduced Length Modeling; Cladding Magnets; Aerospace Lightweighting; Finite Element Modeling

Recommended Citations

Citations

  • Losey, B. (2020). Analysis of Magnetic Gear End-Effects to Increase Torque and Reduce Computation Time [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595514209192582

    APA Style (7th edition)

  • Losey, Bradley. Analysis of Magnetic Gear End-Effects to Increase Torque and Reduce Computation Time. 2020. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1595514209192582.

    MLA Style (8th edition)

  • Losey, Bradley. "Analysis of Magnetic Gear End-Effects to Increase Torque and Reduce Computation Time." Master's thesis, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595514209192582

    Chicago Manual of Style (17th edition)

osu1595514209192582
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