The Study On Dynamic Characteristics And Diagnosis Methods Of Gear Backlash Fault

Gear is a common institution to transfer motion and power, according to statistics, about10.3percent mechanical fault is caused by gear fault. In all kinds of gearbox fault, gears damage ratio is as high as60percent, the existence of gear backlash is also the important factor leading to the damage of gears, gear backlash not only makes gear meshing noise incremental, but also causes impact load, heavy impact load can damage gear teeth and shafts, so it is important to diagnose the gear backlash fault.This thesis focus on studying the gear backlash, the main research contents are as follows:(1) Designed and completed the gear fault diagnosis experimental equipment, which included the hardware and software, many kinds of gear fault can be simulated on the equipment. In the thesis, it simulated the gear backlash mainly, the equipment ran smoothly and the experimental results were good. The expected purposed has reached that the software can acquire and read signal.(2) Done experiments many times under different conditions, such as different rotational speed, different loads, different gear backlash. Summarized the dynamic characteristics of gear backlash fault by statistics and analysis of experimental data. Based on a large number of experimental data and its mathematical statistics, waveform analysis, spectrum analysis, summarized the signal characteristics of gear backlash fault, that the high amplitude impact signal, it also provided proof for gear backlash fault.(3) According to gear backlash fault characteristic signal, used time synchronous averaging, auditory model of Gammatone filter banks, order analysis and actual measured impact response to diagnose gear backlash fault. Usd the method time synchronous averaging, cut out data per5revolutions first, then made each piece of data points equal by interpolation and calculated average value; It was necessary to try different filter number when used the auditory model of Gammatone filter banks, appropriate number of filters was convenient to extract different frequency, it also made the analysis became relatively simple; Order analysis included constant rotational speed analysis and variable rotational speed analysis, it needed encoders to trace the rotational frequency of shafts during the process, under the condition of variable rotational speed order analysis showed its superiority; Fault diagnosis based on actual measured impact response used impact response signal to diagnose impact signal of running gears, it was selected to process gear backlash impact signal specifically, and it was necessary to ensure that the vibration signal sampling frequency and the impact signal sampling frequency was the same, then it will be convenient to process data.