Apparatus and method for testing parameters of involute gears and pinions

摘要

Apparatus for measuring departures from specified parameters for involute type gears and pinions is described. Wheels having a radius of the gear base circle are coupled to the axis of the gears. The base circle radius wheels travel along parallel tracks as the gear/wheel assembly is rotated. To measure the departure of a gear tooth contour from an ideal profile, a probe is forced against the tooth surface on a line tangent to the base circle radius. By definition of an involute gear or pinion, travel of the gear on the base circle results in the tooth profile passing through a point fixed in space on the line tangent to the base circle. By placing the probe in contact with the gear tooth surface on the base circle tangent line, the tooth contour will pass through the point. The probe therefore can determine departures from an ideal tooth profile by displacement of the probe during the travel of the gear/wheel assembly. Similarly, by placing two probes against adjacent gear tooth surfaces (facing the same direction) on the tangent to the base circle, the base pitch parameter can be measured.