Affiliations: [a] Institute of Mechanical Science and Engineering, Jilin University, Changchun, Jilin, China | [b] Institute of Technology, Yanbian University, Yanji, Jilin, China
Abstract: Using interaction forces between two magnetic sleeves,
the contactless magnetic driver changes the rotating motion of a motor into
reciprocating motion by a link mechanism. In an ideal state, the two sleeves
of the driver are coaxial, but due to manufacturing and/or assembly errors,
the real working state is non-coaxial. The air gap and consequently the
magnetic field and interaction forces are altered. Therefore, it is very
important to predict the changing of interaction force for some application.
Assuming that the magnetizations are rigid and uniform, a mathematical model
of the interaction force between two axial magnetized sleeves is developed
based on the theory of equivalent magnetic charges. The model considers two
magnetic sleeves at any relative position and attitude, and is verified
experimentally for the two sleeves being coaxial. A numerical solution is
implemented to compare interaction forces at the coaxial and non-coaxial
states. Through numerical prediction, eccentricity between the sleeves of
0.5 mm generates a radial force approximately 70 N. The modeling method is
also applicable to cuboidal magnets.
Keywords: Magnetic driver, interaction force, non-coaxial, magnetic sleeve, magnetic charges
