RADIAL ANISOTROPIC CYLINDRICAL SINTERED MAGNET AND PERMANENT MAGNET MOTOR

摘要

A cylindrical radial anisotropic sintered magnet in which remanent magnetic flux density in the radial direction of the cylinder increases/decreases at a period of 90° along the circumferential direction of the cylinder, maximum remanent magnetic flux density in the radial direction over the entire circumference of the cylinder is 0.95-1.60T, and the minimum remanent magnetic flux density in the radial direction is 50-95% of the maximum value; and a permanent magnet motor having a plurality of stator teeth and incorporating the radial anisotropic sintered magnets while being magnetized into 4n poles (n is an integer of 1-20) such that the boundary between N pole and S pole is located in the range of ±10° in the circumferential direction with the radial direction exhibiting the minimum remanent magnetic flux density in the middle. The inventive radial anisotropic sintered magnet is free from chipping or cracking during sintering and age cooling processes even in a shape having a small ratio between inside and outside diameters, and has excellent magnetic characteristics. A high-performance permanent magnet motor can be produced inexpensively using the radial anisotropic sintered magnet.