Visual measurement method of pitch machine based on gear local image

Aimed at the high efficient industial measurement demands of small and medium modulus spur gear pitch and the visional image feature, a new single pitch algorithm is proposed based on calculating the tooth image pixel information in gear edge transition zone. The algorithm first extracts the tooth image pixel information in gear edge transition zone with double threshold method. According to the involute geometric characteristics, this image pixel information is adversely mapped to the gear base circle. And the optimal initial phase angle of tooth profile edge involute is calculated. Finally, the gear pitch is obtained by using the initial phase angle of two adjacent corresponding tooth profile. The principle and measuring accuracy of the algorithm are verified by measuring experiments of combined edge obtained with high precision gauges. The results show that the maximum deviation of relative location using this algorithm vesical measurement is 0.002 1 mm, and its maximum dispersity is 0.000 52 mm. By measuring a same 5-level accuracy gear pitch, the gear maximum single pitch deviation obtained by visual measuring instrument occurs in the pitch same to that obtained by M&M3525 gear measuring center. The difference between two results is 0.000 7 mm and the difference of total cumulative deviation obtained by two methods is 0.001 mm. These experimental results indicate that the pitch visual measuring method can meet the requirement of high efficient measurement for 5-level accuracy vertical cylinder gear pitch. © 2018, Science Press. All right reserved.