The formation of locomotive rolling bearing fault and diagnostic methods ( 2) - bearing knowledge

The formation of locomotive rolling bearing fault and diagnostic methods ( 2) 3 bearing fault detection diagnosis of the current domestic use of the bearing fault detection means to roughly measuring temperature, noise and vibration parameters of the method, by using the method of measuring temperature, noise is easier, but the lack of effective preventive action, once in the running high bearing temperature and noise is very big, it was generally supposed that the locomotive bearing has reached to more serious damage. And using the method of measuring the parameters of the vibration, it is when the locomotive in the minor repairs to test the bearing, because in the detection and gathering information is convenient and simple, more suitable for long period of use, is a kind of both simple and practical detection method. 3. 1 the diagnosis method of locomotive bearing bearing method there are two main types: ( 1) Simple and easy diagnosis, locomotive bearing ( 2) The locomotive bearing resonance demodulation spectrum analysis technology - - - - - - - - - - - - - - - - - - - - - - - - Precise diagnosis. 3. 1. 1 simple diagnosis, it is in the vibration detection by testing is usually something the size of the vibration parameters, and the standard values ( Threshold) Compared to judge the state of the bearing, in the simple diagnosis of the locomotive bearing, mainly choose the time domain wave kurtosis coefficient parameters of KV,,,, acceleration RMS Xrms two indicators as fault diagnosis parameters, including kurtosis index KV is a dimensionless parameter, sensitivity to the early failure of bearing, and is not sensitive to operating conditions, when bearing failure of tooth surface work surface, turn every week will have the impact of face defect pulse, the fault, the greater the impulse response amplitude, the greater the KV value rise faster, but with the bearing fault serious deterioration in the late while the KV value declined, and has a value, on the other hand, it is sensitive to early failure is not enough, but as the bearing fault degradation increased continuously, has good stability. In short, to achieve a simple diagnostic confidence a fruit, at the same time using kurtosis coefficient and has a value is appropriate, it both the diagnosis parameter sensitivity and stability. Traction motor bearing ground detection threshold of dongfeng 4 locomotive axle box bearing crown chakra simple diagnostic detection threshold method has a good side, but there are also many shortcomings, when bearing simple diagnosis, of the following would happen; ( 1) Bearing parameter value has fault, but can't determine the failure positions, ( 2) Bearing trouble-free itself but due to the fault resulted from the assembly, ( Of the dynamic imbalance, such as rotor shaft to touch the ground, etc. ) 。 ( 3) On the base, the measured fault signal is strong with the weak ( Minimum inner ring, roller is stronger, the outer ring is larger) , so according to the parameter error is produced. Through the above three kinds of situation analysis, simple diagnosis without judgement method of element bearing fault, can't solve the problem of 'as' maintenance, so bearing diagnosis through the simple diagnosis only judge for XXX is not enough, must be precise diagnosis. 3. 1. 2 precision diagnosis when the bearing surface damage, such as stripping, partial wear, surface corrosion fatigue failure, rolling bearing and Hugh rotation will take turns rolling the surface damage, high speed of inner ring spinning can make this kind of rolling impact, the impact failure caused by longitudinal wave before the material has not yet occurred deformation to launch on the speed of sound, with a steep front waveform and spectrum of the most abundant, with material internal damping, the waves of shock attenuation sharply, so the sensor receives the impact pulse signal. The impact pulse waveform similar to rectangle, the failure frequency of rectangular pulse is extremely broad, and bearing system and all kinds of natural frequency of the sensor is very low, so the bearing on the natural frequencies of the system and all kinds of sense organ is a message was covered with fault impact pulse frequency, failure frequency resonance, provoked a bearing system and each kind of sensor with a bandpass filter filter out unwanted low and high frequency noise, Such as mechanical vibration and other kinds of noise) Only make fault shock pulse excited resonance response waveform through the bearing outer ring or sensor, and the low-frequency fault impact signal amplification and to increase for the vibration system of the response attenuation of high frequency oscillation, envelope demodulation is the high frequency response to zoom in for a low frequency signal, through the frequency for low frequency spectrum analyzer transformation, namely demodulation spectrum. 4 locomotive bearing diagnosis case the following case is on January 27, 2002, dongfeng 7 d0034 locomotive fourth on the left side of the axle box bearing to detect the fault cases, this type bearing 752732. To use JL - 501 bearing inspection units, speed 500 r/min. To detect the diagnostic parameters, the time domain waveform kurtosis coefficient is 6. 63, but also high kurtosis exceeds bid badly, so the test result is unqualified. At the same time spectrum figure to the demodulation spectrum peak is 60 hz, and 1, 2, 3 order peak interval are 60 hz, according to the locomotive bearing fault frequency in the table to calculate the bearing fault frequency: 500 x is 0. 12 = 60 hz, find out the fault parts for the bearing outer ring, from the table in the subsequent decomposition found in bearing outer ring raceway is a little erosion crush marks. 5 conclusion of locomotive rolling bearing diagnosis method described in this article, in my section for nearly two years, my section existing JL - 201 locomotive bearing diagnosis instrument, JL - Two sets of equipment 501 locomotive bearing diagnosis. JL - 201 is mainly used for traction motor bearing surface test and the crown of the locomotive bearing inspection, JL - 501 is mainly used to repair the locomotive rolling bearings for dynamic detection. Two years for other period and the period of repairing of locomotive examined 2318 sets of bearings, detect unqualified bearing 189 sets, which hasn't happened my section from 2001 to the bearing fault or caused by bearing fault machine broken, received a significant results.