Research On Online Automobile Transmission Fault Quick Diagnosis

In order to improve the fault detection accuracy of new transmissions before they launch, reduce jamming influence and consummate quality control, the instrument of SAGW automobile transmission fault detection is developed according to the situation of Shanghai Automobile Gear Works. Under the limitation that each transmission only has about two minutes testing time, this instrument completes the fault detection of all the shifts, speed up and down process, load and unload situations. Compared with every fault detection methods, it confirms the vibration test method. According to the characteristic that the speed changes during test, the old frequency spectrum analysis is no longer available. So we use a more advanced method that is order analysis. After resampling the even-time space vibration signals, they become even-angle space vibration signals. After doing this we can analyze the spectrum from the n times of shaft basic frequency, then the position of every parts in the spectrum is relatively fixed and easy to identify. So the Order Analysis is achieved. Based on such theory, we use virtual instrument to finish the development of software and hardware. The hardware system can acquire all the signals especially the synchronous data acquisition of vibration and speed signals. By using Labview the software system fulfill the signals separation and distill of every shaft. This helps the signal analysis conducts in four individual parallel modules as input shaft, middle shaft, output shaft and synthesis signals and the signals can be analyzed in both time domain and frequency domain. By learning the historical data, the limit curve as judge standard is created. We can know the status of transmission by comparing the limit curve and real curve. Now the instrument is used in the pipeline and has a good effect.