LOCAL FAULT DIAGNOSIS OF NON-STATIONARY GEARBOX BASED ON ORDER ENVELOPE ANALYSIS

摘要

Tooth root crack is a common fault in gear system, it’s of significance to detectrnthe crack fault during the operation process of the gearbox. However, the gearbox usuallyrnworking in a non-stationary condition, namely speed or load are time varying, whichrnincreases the difficulty of fault diagnosis since the statistic features and spectrum vary byrntime. In this paper, an order envelope analysis method is proposed for fault diagnosis of arntwo stage gearbox with local crack fault under non-stationary working conditions. Firstly,rnan accelerometer and an encoder are mounted on the gearbox to acquire non-stationaryrnvibration data and rotating speed, respectively. After that, the angle domain signals arernderived from the non-stationary vibration data by interpolation algorithm. Then envelopernanalysis is employed for the angle domain signals to detect the crack characteristicrnfrequency components in envelope spectrum. Finally, the proposed approach is assessedrnby seeded tooth root crack fault in different working conditions, results show that the newrnmethod can effectively detect the tooth cracks in various non-stationary workingrnconditions.