The invention discloses an automatic torque applying calibrating apparatus for a torque spanner. The automatic torque applying calibrating apparatus is formed by a
servo motor, a
speed reduction mechanism, flexible couplers, connectors, a
torque sensor, radial support mechanisms, a check arm mechanism, a
machine body guide rail and a measuring
control system, wherein the
torque sensor is arranged between the two radial support mechanisms; one end of the
torque sensor is connected with one flexible coupler by one connector while the other end is connected with a square tenon of the calibrated torque spanner by the other flexible coupler and the other connector; the connector connected with the square tenon of the calibrated torque spanner is kept horizontal under the common action of the radial support mechanisms and the flexible coupler, so the
gravity center of the torque spanner is kept vertical and downward. Influence to the toque sensor and the torque spanner caused by poor component generated in the calibration process is avoided, influence to an indication value of the torque sensor caused by the
self weight of the torque spanner is eliminated, the torque applying is automatically performed, the torque applying speed is accurately controlled, the accuracy of the calibrating apparatus for the torque spanner is improved, the calibrating accuracy of the indication value of the torque spanner is improved, the labor intensity is reduced, and the calibration efficiency is improved.