Torque load member and method for manufacturing same, and torque measuring device
A torque load member has a detected surface which is configured to face a magnetostrictive torque sensor. The detected surface is a shot peened surface whose magnetic anisotropy directed in a specific direction has been reduced by performing shot peening thereto at an arc height value of 0.31 mmA or more.
1. A torque load member, comprising:
a detected surface configured to face a magnetostrictive torque sensor, the detected surface having a cylindrical surface shape;
the detected surface being a shot peened surface whose magnetic anisotropy directed in a specific direction has been reduced by performing shot peening thereto at an arc height value of 0.31 mmA or more,
the torque load member having hysteresis of 2.0% FS or less, the hysteresis obtained by a characteristics data with respect to a torque measurement when a torque is measured while a torque loaded to the torque load member is changed so as to reciprocate between positive and negative rated torques.
2. A torque measuring device, comprising:
a torque load member having a detected surface; and
a magnetostrictive torque sensor facing the detected surface;
the torque load member being the torque load member described in claim 1 .
3. The torque measuring device according to claim 2 , comprising
a rolling bearing by which the torque load member is rotatably supported, and by which the torque sensor is supported.
4. A method for manufacturing a torque load member having a detected surface configured to face a magnetostrictive torque sensor, the detected surface having a cylindrical surface shape;
the method comprising:
a step of performing shot peening to the detected surface at an arc height value of 0.31 mmA or more so as to reduce magnetic anisotropy directed in a specific direction of the detected surface,
after the step of performing shot peening, the torque load member having hysteresis of 2.0% FS or less, the hysteresis obtained by a characteristics data with respect to a torque measurement when a torque is measured while a torque loaded to the torque load member is changed so as to reciprocate between positive and negative rated torques.