The vibration of rolling bearings in the gear box of analysis

The vibration of rolling bearings in the gear box of analysis - 2018 07 - 12 in the gear box, also is the main cause of gear box fault rolling bearings, bearing common fault is the inner and outer ring rolling body appeared pitting corrosion and fatigue spalling. Roller bearing inner and outer ring, rolling body fatigue pitting and spalling, the high frequency zone in its spectrum of ring appear near the natural frequency modulation peaks, produce natural frequency as the carrier frequency, outside ring for bearing by frequency modulation frequency of natural frequency modulation phenomenon. Due to the vibration of rolling bearings and gears in the gearbox vibration energy is small, compared to modulation demodulation spectrum amplitude is small, generally only 1 order. Below the gearbox after intermediate shaft bearing ( Model 50308) Inner ring raceway is severe fatigue spalling 1/2 circle, the other half circle flake has a big pit after vibration acceleration spectrum and filtering demodulation spectrum. In the 2000 - 2258 3000 hz. Contains 34 near 3 hz frequency appeared. 23 and 79 hz. 80 hz component of peak modulation, and the measured under free state outer ring first-order natural frequency for 2246. 09 hz, calculate the outer ring and rolling body through frequency of 34 respectively. 47 hz and 23. 6Hz。 Due to the vibration of rolling bearings and gears in the gearbox vibration energy is small, compared to modulation demodulation spectrum amplitude is small, generally only 1 order ( As shown in figure b) 。 From the fault mechanism analysis, in the gearbox shaft, roller bearing inner ring and shaft is tight interference fit more, namely the shaft is an organic whole repeatedly with the inner ring strong, its inherent frequency should be larger energy to excite, and inherent frequency and free state of rolling bearing inner ring measured or calculated frequency is completely different. Cooperation between the outer ring and housing bearing is interference fit, but compared with the inner ring and shaft is much more loose and rolling element and the outer ring in the work are subjected to the high pressure, when the rolling bearing has a fault or take running after a period of time, between outer ring and bearing seat completely loose, basically on the natural frequencies of the outer ring and measured frequency equals the basic free condition. Because of loose outer ring and the quality is small, so not only outer ring rolling body produce pitting or fatigue spalling will provoke its natural frequency, and when the inner ring or defective roller, vibration energy will be through the roller to outer incentive on its natural frequency, so the carrier frequency of the rolling bearings in the gear box generally for the natural frequencies of the outer ring, and the modulation frequency to produce fatigue spalling components ( The inner ring and outer ring or roller) Through frequency. Vibration signal of rolling bearing fault generated energy size and size of gear shaft failure or energy compared to the former is much smaller, so the fault signal submerged in other vibration signals, the characteristics of the fault is not obvious, and brought great difficulty to the diagnosis.