Patent ID: 8797023

Claim:
A coercive force specifying apparatus, at least comprising: a yoke including an insertion space into which a coercive-force distributed magnet is to be inserted, the coercive-force distributed magnet including parts each having a different coercive force; a magnetizing coil that generates magnetic field at the yoke; 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, wherein the yoke has an end face facing the insertion space, the end face being provided with two or more loop-shaped thread grooves of 1 mm or less in depth and 0.3 mm in width bored therein, in each of the thread grooves the search coil being provided, the search coil including conductive wire and insulating coat surrounding therearound, wherein the coercive-force distributed magnet includes a divisional area defined so as to correspond to a plurality of 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, which is implemented at all of the divisional areas to specify a coercive force of the coercive-force distributed magnet.