| 摘要 |
To provide a torque detecting device having a sufficient mechanical strength, capable of accomplishing an accurate torque measurement, having a processability excellent for mass-production, and effective to eliminate problems associated with damages which would be brought about during a heat treatment. This torque detecting device includes a target area subject to torque detection (3) provided in a surface region of a torque transmitting shaft (2) made of a steel material; a detecting coil (4) provided in a non-contact fashion in face-to-face relation to an outer periphery of the target area subject to torque detection (3); and a detection signal processing circuit (5). The target area subject to torque detection (3) is a layer of magnetostrictive material comprised of an A1 diffusion layer. This diffusion layer contains A1 diffused in a steel material in a concentration which gradually decreases from the surface in a direction radially inwardly of the torque transmitting shaft (2). |
