Study On The System Of Marine Gearbox Failure Diagnosis

Fault diagnosis technology of marine gearbox is a subject that need to be developed and improved. It has the character that ensure transmission system running normally, prevent accident, save maintenance cost and so on, plays an important role in the sailing assignments of modern large marines. With the advance of vibration signal processing technology, fault diagnosis technology of gearbox have made great progress. With the new time-frequency methods emerging constantly, the effectiveness and accuracy of the non-stationary vibration signals will be strengthened, the solid foundation will be established on implementation of fault diagnosis of marine gearbox.In this thesis, transmission gearbox of large cruise salvage ship has made as study object, the fault diagnosis of gearbox are based on the testing, processing and analysis of the vibration signals. Because the gears and rolling bearings are important parts in the gearbox, whose failure rate is also the highest, so their fault is notable and will be the key of research in this paper.The structure of this dissertation are listed as follows:Chapter one:The background and significance of this research subject are introduced. The domestic and foreign development and present situation of condition monitoring and faults diagnosis on mechanical equipment is briefly summed up. The main fields of faults diagnosis research on gearbox are pointed out. The analytical methods of vibration signal are summarized. At last the origin of this research subject and research content are briefly introduced.Chapter two:The fault forms and causes of gear and bearing which are in the gear box have been detailedly summarized. Vibration mechanism and vibration signal effect with different inspirit factor have been introduced, and analyzed concoct effect because of concussion which is caused by fault of bearing and gear.Chapter three:For vibration signal of gear and bearing, principle, application range, advantages and disadvantages of the various common methods have been introduced respectively from two aspects of time domain and frequency domain, for disadvantages of single time domain or frequency domain analysis, wavelet analysis has been proposed, which is a kind of time-frequency analysis methods suitable for processing the non-stationary signal.Chapter four:Firstly, the basic theories of time-frequency analysis method and wavelet transform have been introduced, and based on this, through Matlab wavelet toolbox the gear pitting corrosion fault singal is analyzed and processed, the advantages of wavelet analysis have been fully embodied by the results, It is shown that wavelet analysis method an effective analysis technique. This paper also mentioned the limitations of wavelet time-frequency analysis method.Chapter five:The work and innovation of this dissertation are summarized. The problems that are needed to improve and solve on wavelet transform are pointed out.