抄録
An experiment was carried out to examine the application of an Sr-Zn-W-type hexagonal ferrite bonded magnet as a hysteresis bonded magnet in a non-contact-type torque limiter using a magnet. The magnetic properties of Sr-Zn-W-type hexagonal powders ware first examined in order to prepare a bonded magnet. The preparation conditions for a typical sample were as follows: chemical analysis composition, Sr2+0.93Zn2+0.93Fe2+1.02Fe3+16.07O27; reaction sintering condition, 1300°C × 4.0 h in air; average particle size after pulverizing, 0.85 μm. The magnetic properties of Sr-Zn-W-type hexagonal ferrite powders are σs = 95.5 × 10-6 Wb·m/kg, HcJ = 60.5 kA/m. Next, an injection molding bonded as a hysteresis bonded magnet was prepared by using these powders and Sr-M-type ferrite powders. Non-contact-type torque limiters were made experimentally by using these bonded magnets. The torque value of a torque limiter prepared from an Sr-Zn-W-type ferrite bonded magnet was found to be better than that of a torque limiter prepared from an Sr-M-type ferrite bonded magnet, and the leakage magnetic flux decreased by 13%.
