Torque sensor for electric motor

摘要

The sensor has two shafts (1,2) rotating co-axially and a torsion bar (3) linking the two. A tubular element (4) of conductive and non-magnetic material is linked to and rotates with the second shaft and surrounds part of the peripheral surface of the first shaft, the whole being enclosed by a coil (10,11). A dynamometer measures the strength of the electro-motive forces generated by the coil. Part of the section (1A) of the first shaft surrounded by the tubular element is of magnetic material and has axial slots (5a,5b). The tubular element contains windows (4a,4b) arranged so that they partially cover the slots and the resultant overlap is varied according to an angular position of the tubular element relative to the first shaft. The coil encloses the region of the tubular element in which the windows are formed so that a torque generated in the two shafts can be recorded based on the forces measured by the dynamometer.