Fault Feature Extraction Of Planetary Gearbox Based On Windowed Vibration Separation Method

The planetary gearbox has the advantages of large gear ratio,small volume,stable operation,and large carrying capacity relative to the fixed axis transmission,and it usually operates under harsh environments such as low speed,heavy load,gusts,etc,and gears are prone to failures such as shedding,pitting,and cracks.On the other hand,the planetary gearbox transmission system is more complicated.When it is driven,the sun gear rotates around its own axis,and one or more planetary gears not only rotate about its own axis,but also rotates with the planet carrier around the fixed axis of the sun gear and mesh with the sun gear and the ring gear at the same time,the meshing position of the two meshing pairs and the position of the sensor rotate along with the rotation of the planet carrier,thereby causing a time-varying vibration transmission path between the sensor and the meshing vibration source,and the conventional gear vibration analysis method.Cannot be applied directly.In addition,in order to make the load evenly distributed,the number of planetary gears is usually more than one.The vibration signal picked up by the sensor is a superposition of multiple sets of meshing vibrations,and the planetary gearbox usually works in harsh environments.Its vibration signal modulates the composition and the gears are complex.The characteristics of early faults are relatively weak,making it difficult to identify planetary gearbox gear failures.In this dissertation,industrial planetary gearboxes(2K-H planetary transmissions)are studied as the research object.Based on the characteristics of time-varying vibration transmission paths of planetary gearboxes,Based on previous studies,a synchronous average method for vibration signals of planetary gearboxes based on vibration separation has been developed.The method firstly verifies the characteristics of meshing tooth sequence of gears,selects Tukey window according to the tooth sequence features to perform multi-tooth wide-window interception,and then constructs the target gear vibration signal according to the rearrangement tooth sequence and window interception signals to suppress the time-varying vibration transmission path.influences.Finally,the vibration separation signal is synchronized and averaged to further eliminate noise and non-synchronous component interference,and extract the synchronization components of interest.In order to solve the time-varying vibration transmission path and non-stationary weak fault extraction problem of planetary gearboxes,this paper proposes a novel fault feature extraction method based on angle-domain and window-synchronized average of envelope signals.The method firstly extracts the envelope signal of the planetary gearbox vibration signal based on the spectral kurtosis;secondly,it computes the equal-angle resampling of the envelope signal using the computational order tracking technique,then performs vibration separation on the angular domain signal,and finally separates signals from the vibration.The angular domain synchronization average is performed to extract the fault features of the planetary gearbox.Based on the above research,a method of narrow-band demodulation for planetary gearboxes is proposed in combination with the synchronous average and narrow-band demodulation methods for planetary gearbox vibration separation.Vibration separation of planetary gearbox vibration signal to overcomes the effect of degeneration of the transmission path;the time-domain synchronization of the vibration separation signal is averaged to improve the signal-to-noise ratio;Finally,the averaged signal is subjected to narrow-band demodulation to extract fault characteristics and fault location of planetary gearbox gears.In combination with the improved MED method in foreign countries,the multi-point optimized minimum entropy deconvolution(MOMEDA)is used to enhance the fault impact characteristics of planetary gearboxes and to achieve planetary gear gearbox fault feature extraction.The simulation analysis of the tooth root crack of the planetary gearbox is carried out to test the effectiveness of the proposed method.