Gears are rotating mechanical parts with excellent power transmission efficiency and are widely used in machine tools, automobile, industrial machinery, and aviation industries. To enhance the performance of the gear, optimized design of the gear geometry is paramount. In this paper, we optimize the geometric tooth profile of helical gears which are among the gears of the transfer case gearbox by using the finite element program, Romax Designer to model and analyze the load and gear teeth of the gearbox power transmission system. The optimized gears were fabricated and compared to the results of the gear tests.

The gear ratio variable topology of a magnetic gear with an integrated harmonic modulator is analyzed using a magnetic permeance model. A dynamic characteristic equation is derived in consideration of the gear ratio between each layer constituting the magnetic gear: the driving side, the driven side, and the control side layer. Based on derived transfer function, the frequency characteristic between driving torque and angular speed of the driving side is analyzed. Theoretic model is compared with an experimental test result using the in-house dynamometer. In the general magnetic gears, the gear ratio is variable so that speed between each layer decelerates with gear ratio, but transmission torque is constant regardless of gear ratio. In this study, these characteristics are also verified through theoretical methods and experimental results, respectively.