Influence Factors on Torque Testing of Cylindrical Helical Torsional Springs

The torque testing process of cylindrical helical torsional springs was analyzed. Some factors which influence the torque testing results were discussed, such as the mandrel diameter, the location of torgue, the coaxiality, the mandrel surface roughness, the initial torque, the loading rate and etc. The determination principles of these factors which should be considered in torque testing process were provided as following. The mandrel diameter should be chosen by the formula in GB/T23953—2005, which should be 0.8~1 times of the calculated value. The location of load could be about 0.75 times of the torsional arm length from the torsional arm tangent point. The initial torque could be chosen by 2%~5% of the measured torque maximum value. The location of load should not be too far from the measuring discface. The hardness of mandrel and stop lever should be not less than 40HRC. The mandrel surface roughness should be less than 1.6 μm. The above research results on torque testing method would provide important basis to the establishment of torque testing method standard.