Analysis And Structure Improvement On The Key Components Of Cutting Platform On Combine Harvester

Combine harvester is a common machine for mechanized harvesting of rice,which plays an irreplaceable role in agricultural activities.Mechanism driving Cutter and the drive shaft in cutting platform are the key components of combine harvester,and their working capability directly affects the quality and efficiency of the harvesting.At present,the most domestic combine cutters are generally driven by crank-connecting rod mechanism.Because of its structural characteristics,the cutter rod is subjected to vertical force for most of the time,which leads to frequent breakage of the cutter rod.Therefore,it is necessary to improve the driving mechanism of the cutter to improve the reliability of the cutter.Because there is no reliable load spectrum data as the basis for the design,when designing the strength of the drive shaft of the cutting platform,it is often in a blind state.According to the existing structure,the design is carried out and the safety factor is too high.Therefore,it is necessary to test the load of the drive shaft of the cutting platform so as to make it more reasonable design the drive shaft of the cutting platform.On the basis of 4LZ-5.0Z self-propelled full-feed combine harvester,the key components of the cutting platform,the cutting driving mechanism and the driving shaft of the cutting platform,are analyzed and improved in this paper.The main research contents are as follows.(1)The linear motion principle of the cutter planetary gear drive mechanism is briefly described,and the force on the cutter rod of the designed mechanism is compared with that of the existing cutter drive mechanism.The design of the internal meshing gear pair is completed,and the shafting parts are designed preliminarily.(2)By using the software in design of transmission system,Romax,the static strength check and life evaluation of the shafting parts of the mechanism,including gear pairs,planetary gear shafts and bearings,are carried out under design conditions.At the same time,the tooth profile of the gear pair is optimized to provide design reference for the design and manufacture optimization of the cutter planetary gear mechanism.(3)The load of the drive shaft of the cutting platform in the actual operation of the combine was tested in the field.The time history of the torque load of the drive shaft of the cutting platform under two typical working conditions,namely,no harvesting and medium harvesting,was obtained.(4)According to the characteristics of the original load signals collected,the singularity points are removed and the processed payload signals are analyzed by rain flow counting method.The rain flow histogram of the torque load is obtained,which is used to the subsequent fatigue life prediction.(5)Summarize the fatigue failure forms and influencing factors,discuss several methods of fatigue life analysis,creat S-N curves of the drive shaft of the cutting platform,combine with the measured load spectrum,use Goodman formula to correct the average stress,and use the fatigue analysis software,nCode,to calculate the fatigue life of the drive shaft of the cutting platform.After that,according to the life requirement of the transmission shaft of the cutting platform,the diameter of the shaft is optimized to avoid excessive safety margin.