Rotating shaft torque on-line testing apparatus based on current vortex relative displacement measurement

The utility model relates to a rotating shaft torque on-line testing apparatus based on current vortex relative displacement measurement. Through mechanisms of a clasp, a displacement measurement arm, a displacement reference arm, an auxiliary support and a constraint damper and the like, the measurement on the rotating shaft torque is ingeniously converted to the measurement of a relative displacement of two points. The measurement of a relative displacement employs a reflection type current vortex displacement sensor which has capability of bad environments such as dust, oil stain, smog, wetness proof and has high displacement measure resolution and precision. Zero calibrate can be performed at any moment, and forward and backward on-line testing is performed, especially the testing apparatus can be used under conditions of large diameter of axle, strong rigidity, small torsion angle and bad working environment. According to the utility model, through integration measures of a trapezoid beam, a constraint d