Fault Analysis And Diagnosis Method For Threshing System Of Combine Harvester

Mechanized harvesting has become an important way of rice production and an important guarantee of efficient rice harvest in China.However,due to the influence of rice growth and machine speed during rice harvesting,the feeding amount often fluctuates greatly,which also induces the sudden change of the threshing drum load.Among them,the change of combine harvester speed,crop grass-grain ratio,stubble height,and grain density will cause the change of feeding amount.The variation of feeding quantity in a small range will cause the fluctuation of load,and the variation beyond a certain range will cause the mutation of load,resulting in the system of threshing drum blockage,spindle torsion,transmission chain fracture and other faults.Based on National Key Research and Development Projects(2017YFD0700203),this paper studied the fault of multi-drum threshing system induced by load mutation.The failure mechanism of threshing system of combine harvester was explored by combining theory with experiment analysis and simulation analysis.Looking for threshing process representation signal as the threshing fault judgment basis and put forward fault diagnosis method develop combine harvester status monitoring and fault diagnosis system based on Android mobile phone.This study has scientific significance and application value for reducing the failure rate of harvester field harvesting operation and improving the reliability of harvester.The main research contents of this paper include:(1)The power distribution mode and distribution mechanism of multi-drum detachment system were analyzed through field load test.The structure of threshing system of combine harvester was reasonably simplified and the driving model of the system was constructed.The running condition of threshing drum was analyzed by Adams motion simulation,which provided theoretical basis and experimental basis for the study of fault diagnosis of combine harvester.(2)The threshing drum of combine harvester was simulated by Ansys finite element method,and different operating conditions of threshing drum were simulated by bench test.The speed change and vibration response of the threshing drum under different conditions under transient load were determined,and the fault signal of the threshing drum was found,which provided experimental basis and theoretical support for the study of fault diagnosis method.(3)Developed the state monitoring and fault diagnosis system of combine harvester,which can monitor the change of working parameters of combine harvester in real time,including speed,temperature and vibration parameters.The curves and data of each parameter can be dynamically updated in time,and the data delay was 100 ms,meeting the monitoring requirements.It can make fault warning and alarm accurately when combine harvester was working in field.(4)The bench test was carried out using the threshing drum’s rotational speed and the vertical vibration signals of the shaft end as the representation signals,and the normal and failure conditions of the threshing system of the combine harvester were simulated,and the fault judgment criteria of the threshing system were obtained.The results showed that the vibration signals in the vertical direction of the drum shaft end have obvious characteristics when the frequency was 50 Hz.When the threshing drum was blocked,the vibration response of the vertical vibration signal at the shaft end of the threshing drum reaches the maximum value when the frequency was 24 Hz.And the vibration peak value was also obvious when the frequency was about 100 Hz.