Accelerated Verification Study On The Reliability Of The Motor Drive Mechanism Of Corn Precision Seed Dispenser

Motor driven seed metering technology is the development trend of corn precision sowing.The working environment of the corn precision seeder is severe and the working conditions are complex and variable.The key component of the seeder,the motor drive mechanism,bears the effects of variable loads,and the reliability of the operation is greatly tested.Therefore,this article has conducted a reliability accelerated verification study applicable to the motor drive mechanism of the corn precision metering device,which covers three parts: reliability analysis of the motor drive mechanism of the corn precision metering device,construction of a reliability accelerated verification model based on field conditions,and reliability accelerated verification tests of the motor drive mechanism of the corn precision metering device.The main research contents are as follows:(1)Reliability Analysis of the Motor Drive Mechanism of the Corn Precision Metering Device.Based on the actual working conditions of the motor drive mechanism of the corn precision metering device,the composition of the motor drive mechanism of the corn precision metering device was analyzed,and a reliability model was established.Failure mode and effects analysis(FMEA)and fault tree analysis(FTA)were conducted to obtain the causes and effects of the motor drive mechanism failures and establish a fault tree,The minimum fault cut set and reliability life data of the motor drive mechanism fault tree are obtained.Theoretical analysis shows that the total failure efficiency of the motor drive mechanism is 78.67256 × 10-6/h,with an average life of12710.91h;Motor importance is 79.31%,Hall switch importance is 19.78%,resistor importance is 0.72%,and electronic circuit importance is 0.19%.(2)Construction of accelerated reliability verification model based on field conditions.A dynamic testing system with the National Instruments C-DAQ host as the core was built.Using the John Deere 1204 tractor and the DEBONT air suction seeder as the testing platforms,field actual working conditions tests were conducted under the static working conditions(tractor idling,seeder seeding)and operating conditions(tractor driving,seeder seeding)of the seeder.The influence of vibration load on the temperature rise of the motor drive mechanism during field operation of a seeder was analyzed.The average values of the vibration correction coefficient k under the corresponding operating conditions of four motor speeds during seeding,namely,1000 rpm,1500 rpm,2000 rpm,and 2500 rpm,were calculated to be 0.155,0.186,0.207,and 0.228,respectively.The calculation formula for the acceleration coefficient A was improved,and a reliability acceleration verification model based on field operating conditions was constructed,Completed the design optimization of the accelerated reliability verification test for the motor drive mechanism.(3)Accelerated reliability verification test for motor drive mechanism of corn precision metering device.An indoor accelerated verification test rig was built and accelerated verification tests including temperature rise test and accelerated life test were carried out.Through the temperature rise test,the temperature rise of the motor drive mechanism of the corn precision metering device under different working conditions was obtained,and the acceleration coefficient values under different working conditions were calculated.On this basis,the accelerated life tests of 96 motor drive mechanisms were conducted,and the reliability life data of the motor drive mechanism under accelerated stress conditions were obtained.The experimental analysis shows that the reliability life data of the motor drive mechanism of the corn precision metering device under accelerated stress conditions can better correspond to the reliability theoretical analysis results.The fitting results of the graph analysis also conform to the exponential distribution.The absolute error of the accelerated verification test and reliability analysis importance results is 0.14 percentage points,and the relative error of the average life results is 3.3%.The accelerated verification test results show the accuracy of the reliability theoretical analysis carried out in this paper.