| 摘要 |
<p>In the surface of a shaft base material, a knurling groove is made in the direction inclined to the direction of the shaft axis, and further, a heat treatment is applied. Then, on the surface of the shaft base material including at least the knurling groove, a magnetostrictive layer is formed by plating, flame coating, or the like with a material which has a small crystalline magnetic anisotropy and a large magnetostriction constant. It is preferable that the magnetostrictive layer is of an FeNi alloy plating layer, and the content of Fe in the alloy layer is 0 % or more and 25 % or less. In such a way, it is possible to obtain a sensing shaft having an extremely high-performance magnetostriction type torque sensor. In order to enhance the adherence between the shaft base material and the magnetostrictive layer, it is preferable to subject the surface of the shaft base material to a treatment such as shot peening or nickel strike plating before the formation of the magnetostrictive layer. By this surface treatment, it is posible to obtain a torque sensor having an excellent durability.</p> |
