Normal vector centering method for probe correction in cylindrical worm tooth profile measurement

Abstract

Abstract The measurement results of cylindrical worms vary greatly under different probe tip diameters on the Gear Measuring Centre (GMC). Considering toroidal enveloping cylindrical worm (ZC1 worm) as an instance, after analysing the worm grinding coordinate system, the probe correction method based on normal vector centreing (NVC) is established. The theoretical coordinate values of the points on the normal equidistant line which is rotated into the axial section are used as the probe tip centre trajectory. Experiments were carried out with probe tip diameters of 1.0 mm, 1.5 mm and 2.0 mm for the worm tooth profile measurement on a GMC. Compared with the traditional method, the variation between the profile deviations results using the proposed method become smaller and the variation of ‘profile deviation, total’ is reduced from 8.3 μm to 0.5 μm, the profile slope deviation variation is reduced from 8.6 μm to 0.5 μm. The proposed method in ZC1 worm tooth profile measurement can effectively reduce the variation between the measurement results under different GMC probe tip diameters, and also the methodology can be applied to other kinds of cylindrical worms. The method has significance for other curved profiles measurement on coordinate measurements.