Coercivity specifying device

Abstract

Provided is a coercive-force specifying apparatus capable of creating a demagnetization curve for each divisional area of a coercive-force distributed magnet without breaking the coercive-force distributed magnet and of specifying an average coercive force for each divisional area precisely. A coercive force specifying apparatus of the present invention includes: a yoke including an insertion space into which a coercive-force distributed magnet is to be inserted; a magnetizing coil; a search coil that detects a magnetization change when the magnetic field is applied to the coercive-force distributed magnet; and a tracer that creates a demagnetization curve on a basis of a voltage value generated due to the magnetization change. The end face is provided with two or more loop-shaped thread grooves bored therein, the search coil being provided in each thread groove. The coercive-force distributed magnet includes a divisional area defined so as to correspond to each of the two or more search coils, and a voltage value due to a magnetization change detected by each search coil is transmitted to the tracer for creation of a magnetization curve at a corresponding divisional area as well as for specification of an average coercive force.

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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