| Wear is material constantly damage due to the friction in relative motion betweencontact surfaces, accounting for more than80%of total tribological loss, causing a hugeloss on the national economy. While the particles produced by wear of friction parts invehicle transmission system entered the hydraulic lubrication system, they exacerbated thewear of friction parts. By monitoring the wear particles, the working condition of vehicletransmission system can be reflected. It is of great significance to realize the oil monitoringfor vehicle transmission system condition monitoring, furthermore the key parts in oil online monitoring are the development of online monitoring sensor and the recognition ofweak particle signals.Aimed at three-coil differential inductive wear debris sensor, for its weak, small SNRand mix output signals, the sensor output signal lock-in amplify processing method wasstudied by theoretical modeling, simulation and experiments, furthermore the sensor outputfunction was fitted. The characteristics of signals due to multiparticles passing through thesensor was researched as well. The research of this topic promoted the development andapplication of this kind of sensor and the recognition of signals, and provided someimportant significance to the realization of oil wear particles online monitoring. The maincontents were as follows:①The theoretical model of sensor was established by studying on the detectionprinciple of three-coil differential inductive wear debris sensor and the characteristics ofinduction coil voltage signal was Analyzed. Then the method of induction voltage signalprocessing was researched according to the lock-in amplifier principle, chose the type oflow pass filter and designed its parameters, a DC sinusoidal output signal was finally got.②The model of sensor magnetic field was improved based on two-coil model, gotthe sensor magnetic field with different radial distribution and the effects of particle radialposition on the sensor axial magnetic flux. A model of multi-particles passing through thesensor at the same time was established, leading to the conclusion that the sensor outputpeak is proportional to the total volume of the particles. ③The sensor output model was established, the method of getting information of theparticles from the output sinusoidal signals was found, the demagnetization factor of theparticles in different shapes was researched, the changing rules of sensor output signalswhen spheroidal particles and axial cylindrical particles were in different shapes werediscovered by simulation analysis.④The sensor output signal function both in simulation and experiment were fittedaccording to the signal peak voltages, and the size of particles was divided into smallsegments based on the output signal function, the reliability of division result was verified.⑤An experiment system was designed and built, and the tested particles wereprepared. The influence of particles size and their oil environment on the sensor outputsignals was researched. The effect of the particle radial position on the sensor output signalswas verified by experiment. |
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