Coercivity specifying device

Abstract

Provided is a coercive force specifying device capable of creating a demagnetization curve for each segmented area of ​​a coercive force distributed magnet without destroying the coercive force distributed magnet or the like, and capable of accurately specifying the average coercive force for each segmented area. The coercive force specifying device of the present invention includes: a yoke having an insertion space into which a coercive force distribution magnet can be inserted; an exciting coil; and a detection coil for detecting a magnetization change when a magnetic field is applied to the coercive force distribution magnet. ; and a tracer for demagnetization curve based on the voltage value produced by the magnetization change, two or more annular grooves are opened on the end face, and detection coils are arranged in the grooves, which are stipulated in the coercive force distribution magnet For the divided regions corresponding to each of the two or more detection coils, the voltage value generated by the magnetization change detected by the detection coils is sent to the plotter, and the demagnetization curve of the corresponding divided region is created, and the average coercive force is specified.

Description

technical field [0001] The present invention relates to a coercive force specifying device for performing the above-mentioned processing on all the divided areas by creating a demagnetization curve for each divided area of ​​a coercive force distributed magnet used in a motor, etc., and specifying the average coercive force of each divided area. , so that the specific coercive force distribution magnet coercive force. Background technique [0002] A permanent magnet embedded in a rotor of an IPM motor or the like requires a coercive force capable of resisting demagnetization by an external magnetic field incident from the stator core side. [0003] The external magnetic field acting on the permanent magnets is generally largest at the corners of the permanent magnets on the stator core side and smaller at the center of the rotor core when the rotor in which the permanent magnets are embedded is viewed planarly. [0004] On the other hand, for the sintered permanent magnet, ...

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Problems solved by technology

[0007] However, at present, only a method of specifying the coercive force by forming a divided piece of a magnet that destroys the coercive force distribution is applied.

In addition, even if the coercive force measuring methods disclosed in Patent Documents 1 and 2, which are prior art disclosures, are used, the average coercive force of the entire coercive force distribution magnet can be measured, and the coercive force distribution magnet cannot be specified. The average coercive force of each part (each segmented area) of

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