| 摘要 |
PURPOSE:To detect torque at low cost by converting torsional displacement to change in magnetic flux quantity by a prescribed structure and detecting the change in the magnetic flux quantity in non-contact. CONSTITUTION:A first shaft 1 is connected to a second shaft 3 via a small diameter portion 2 for reducing torsional rigidity a little. The projection 4a of a cylindrical mold member (nonmagnetic material) 4 is fixedly attached to the circumferential surface of the shaft 3 such that the projection 4a wraps the small diameter portion 2. The member 4 constitutes a torque detecting mechanism together with a pickup member 8, a Hall element 11 and the like. The magnetic body embedding portion 4b of the member 4 is alternately and concentrically arranged with eight magnetic bodies 5a positioned so as to be directed toward a pole N and eight magnetic bodies 5b positioned so as to be directed toward, a pole S, both on the end surface 4c of the magnetic body embedding portion 4b. When magnetic force generated from the magnetic bodies 5a and 5b is detected, torsional displacement produced between the shafts 1 and 3 is caught as change in a gap space between the magnetic bodies 5a and 5b and projected teeth 9a. The change in magnetic flux quantity produced by the change in the gap space is accurately detected as indicating a torque by the element 11 provided in non-contact with the member 8.
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