| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for specifying a coercive force of a coercive force distribution magnet, capable of precisely identifying the coercive force (average coercive force) in an arbitrary region (arbitrary virtually divided areas) of the coercive force distribution magnet without destroying the coercive force distribution magnet.SOLUTION: A coercive force specification method includes the steps of: virtually setting a plurality of divisional areas A1-A7 in an arbitrary plane extending in an easy magnetization direction of a coercive force distribution magnet E, creating a demagnetization curve of each divisional area according to a measurement result by search coils 3a-3g corresponding to the divisional areas, respectively, and removing as needed an error due to demagnetization of a divisional area positioned relatively inner side so as to correct the demagnetization curve; performing second order differential to each demagnetization curve so as to identify magnetic flux density Bx of an inflection point indicating a demagnetization starting point on the demagnetization curve; and setting a recoil ratio μr being a material constant of the coercive force distribution magnet as a gradient of a straight line, and substituting an identified Bx with a relational expression including residual magnetic flux density Br, coercive force Hx and magnetic flux density Bx, so as to obtain Hx. |
