POLARIZING METHOD FOR MAGNET FOR THRUST MAGNETIC BEARING AND MAGNET FOR THRUST MAGNETIC BEARING

摘要

PROBLEM TO BE SOLVED: To provide a polarizing method for a magnet for a thrust magnetic bearing and the magnet for the thrust magnetic bearing which improves stability of rotation by removing influence due to unevenness of precision on dimension of the magnetic bearing and magnetic characteristic.;SOLUTION: Polarization of the magnets 41, 42 for the thrust magnetic bearing, for example, polarization in the radial direction of each magnet 41, 42, is performed based on the following formula so that a branch position P in the radial direction of lines of magnetic force M of each magnet 41, 42 coincides with an intermediate position of inner radius R₁ and outer radius R₂ of each magnet 41, 42. W(R)=a×k₁(R)×{(1/(R-R₁)²)}+b, wherein R: distance in the radial direction from the center of each magnet; R₁: inner radius of each magnet; R₂: outer radius of each magnet; k₁(R): coefficient obtained by taking permeability in a material around each magnet into account; a: amount of polarization on inner peripheral face of each magnet; b: constant for compensating magnet leak magnetic flux; and W(R): amount of polarization in distance R in the radial direction.;COPYRIGHT: (C)2003,JPO