On the pitch curve of non-circular gear, the arc length between two adjacent tooth profiles on the same side is called the pitch on the pitch curve. The single pitch deviation refers to the algebraic difference between the actual pitch and the theoretical pitch on the pitch curve on the end plane of the non-circular gear. For the non-circular whole gear with large number of teeth and high precision requirements, evaluation 1 is required The accumulated pitch deviation refers to the algebraic difference between the actual arc length and the theoretical arc length of any k pitches on the end plane of non-circular gears
Three measuring methods are used to measure the same first-order elliptic gear. The single pitch deviation and cumulative pitch deviation measured by CMM are expressed as fpt1 and FP1 respectively; the single pitch deviation and cumulative pitch deviation measured by articulated arm scanner are expressed by fpt2 and FP2 respectively; The single pitch deviation and cumulative pitch deviation measured by 3D scanner are represented by fpt3 and FP3 respectively.
Through the analysis, it can be seen that the maximum cumulative error of gear pitch measured by CMM is 0.2158 mm; the maximum cumulative error of gear pitch measured by articulated arm scanner is 0.164 2 mm; The maximum cumulative error of gear pitch measured by three-dimensional scanner is 0.0657 mm. It can be seen from the table that the accuracies of cumulative pitch error measured by three different measuring methods are 12, 11 and 8 respectively.