Research On The Wavelet Analysis Theory In The Fault Diagnosis Of The Gearbox

As a result of enlargement, automation, complication and succession of sophisticatedequipment and the keen market competition in recent years, people raise a higher claim foraccuracy and speediness of mechanical failure diagnosis. The gear drive is one of the mostgeneral modes in mechanical equipment, the importance of the condition testing and faultdiagnosis of its transmission system consists not only in cutting time and cost of repairing,butalso in raising diagnosing accurate, which improves repairing quality and acquires economicbenefits dramatically.In this thesis,some research and application work with wavelet and wavelet packet in thefield of fault diagnosis of gearbox has been conducted. And wavelet analysis,a new timeand frequency analysis method,is used in the field of mechanical fault diagnosis. The type ofthe gearbox is JZQ250 and made as test object. Firstly, based on the fault mechanism andvibration trait of the gearbox in the practical state of work, the experiment project oncondition testing and fault diagnosis of the gearbox is designed, the vibration signals of thegearbox are tested and denoised by applying the wavelet packet analysis. Secondly, The vibrationtrait information of the gear's wearing is identified on the basis of wavelet coefficient. While this textdiagnoses bearing's failure such as spot with power spectrum. Finally, it is an effective and reliable methodto analyze signals and diagnose gearbox on the basis of wavelet alternation.The result of the experience represents that the fault in the gearbox can be detected andfault pattern can be identified validly. Wavelet analysis compensates the shortcoming offlourier alternation. It can analyze signal in both rime and frequency domain. It is because ofthis that we can pick up our needed signal. Moreover, it is an effective and reliable method toanalyze signals with spectrum on the basis of wavelet alternation.