Abstract: A screw pair including inner walls of screw holes in a working nut and a pre-tightening nut with sensor groups including a plurality of displacement sensors capable of measuring a value of a gap between an inner and outer wall of a screw in a diameter direction of the screw hole, the group includes four displacement sensors evenly distributed in a circumferential direction of the screw hole, every two displacement sensors are paired and symmetrical about a center axis, and projections of a plurality of sensor groups in an axial direction overlap the screw; and an adaptive excitation coil is mounted to each displacement sensor, which is capable of attracting the screw in a measurement direction of the adaptive displacement sensor, and a magnetic force of the coil attached is adjustable to change the value of the gap, so that axes of the screw, working nut, and pre-tightening nut coincide.

Abstract: A screw pair including inner walls of screw holes in a working nut and a pre-tightening nut with sensor groups including a plurality of displacement sensors capable of measuring a value of a gap between an inner and outer wall of a screw in a diameter direction of the screw hole, the group includes four displacement sensors evenly distributed in a circumferential direction of the screw hole, every two displacement sensors are paired and symmetrical about a center axis, and projections of a plurality of sensor groups in an axial direction overlap the screw; and an adaptive excitation coil is mounted to each displacement sensor, which is capable of attracting the screw in a measurement direction of the adaptive displacement sensor, and a magnetic force of the coil attached is adjustable to change the value of the gap, so that axes of the screw, working nut, and pre-tightening nut coincide.