| 摘要 |
PURPOSE:To make the hysteresis at the time of torque detection small, to improve linearity and to enhance torque detecting sensitivity. CONSTITUTION:A shaft base material consisting of a structural steel is hardened in a process 1. A magnetorestrictive material consisting of an Fe-Al alloy having 13 to 16wt.% content of Al is thermally sprayed to integrate a magnetic thin film on the shaft base material, by which a shaft material is formed in a process 2. The magnetic thin film covering the outer periphery of the shaft base material over the entire periphery is subjected to surface working and, simultaneously, the front surface side of the magnetic thin film is subjected to machining for the purpose of forming magnetically anisotropic parts in a process 3. Next, the shaft base material is heated to, for example, 400 to 900 deg.C, preferably to about 500 deg.C or about 850 deg.C in the state of supplying pressurized gaseous Ar in a heating stage of a process 4. The entire part of the shaft base material is immersed into an oil liquid in the gaseous Ar, by which the shaft base material is rapidly cooled in a rapid cooling stage of a process 5.
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