Patent ID: 6128964
Filing Date: 2000-10-10
Classification: G01L

Abstract:
A torque transducer comprising a transducer shaft with a circularly polarized magnetic ring fixed to the periphery of the transducer shaft, wherein the circularly polarized magnetic ring is concentrically surrounded by a stationary tubular shell which is freely arranged in relation to the shaft and in which is generated an axial static magnetic field originating from the circularly polarized magnetic ring when the transducer shaft is loaded with a torque, and wherein the magnitude of the static magnetic field is determined by the magnitude of the torque in question, the shell is provided with at least one winding which is supplied with an alternating current of a given frequency for axial time-varying magnetization of the shell, a phase-sensitive detector for detecting and supplying a signal corresponding to the content of those voltages with even harmonics, which are induced in the winding because of the static magnetic field, of the frequency of the given magnetization current, the signal is connected to a controller for supplying a direct current proportional to the signal connected to the winding and with such a polarity that it counteracts the static axial field occurring when loading the shaft with a torque, and said direct current constitutes a measure of the torque with which the shaft is loaded.