| Summary: | 碩士 === 國立中正大學 === 物理學系 === 84 === The torque of magnetic coupling with different magnetic
poles has been investigated by theoretical computations with two
dimensional modeling processes of finite element analysis. The
torque is sensitive to the number of magnetic poles, the
material of the magnetic gears, and the distance between the
magnetic gears. For a 2 mm separation distance of two magnetic
gears with 20 mm radius, the maximum torque occurs between 6 and
20 poles which is dependent on the thickness of the iron yoke
inside the magnets, and on the magnetization configuration
within a pole of the magnets. This is explained by analyzing the
magnetic coupling strength of each pole. Finally, the computer
calculation is tested using an experimental data taken from a
sintered NdFeB magnetic gear. The torque of the radial
magnetic coupling between perpendicular magnetic gears with
different magnetic poles has been investigated experimentally.
The torque of magnetic coupling decreases with increasing the
distance between the magnetic gears. For different multipole
magnetic couplings with the same magnetic field strength, the
torque of magnetic coupling is proportional to the number of
magnetic poles at distances smaller than a critical separation
distance dc, but it is inversely proportional to the number of
magnetic poles as the separation distance becomes larger than
dc. This critical separation distance for our sintered NdFeB
magnet system is 10 mm. This phenomenon is explained by
analyzing the magnetic coupling strength of different poles of
magnets on the perpendicular magnetic gears.
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