Design And Experiment Of Cone Diversion Type Soybean High Speed Precision Seed-metering Device

Aimed at the problems of reduced sowing precision,poor uniformity of plant spacing under high-speed operating conditions of mechanical seed metering devices,provide the technical idea of using a deflector and cone disc to change the relative static state of the inner layer seed populations,improving the movement speed and filling force of the outer layer to be filled,a cone diversion deflector type soybean high-speed precision seed metering device was designed.Through theoretical analysis and structural design,parameter simulation test,bench test,vibration test,filed test,the optimal structural parameters of seed metering device were determined and explore the impact of the performance of the seed metering device under vibration conditions,which provide a technical reference for the design and performance improvement of mechanical high-speed precision metering device.The research content and conclusions as follows:（1）Structure design and theoretical analysis of cone diversion type seed metering device.In order to improve the high-speed operation quality of the mechanical seed metering device,a seed metering device with deflector,cone disc and compound hole was designed.The seed metering device drives the seed population movement through the deflector and cone disc to realize"dynamic seed filling",combined with the compound hole structure to guide the seeds to be filled to complete the filling,which effectively improved the speed and filling force of the seeds to be filled.The structure design,working principle,working process of the seed metering device and the main components and structural parameters that affect the working performance have systematically analyzed.The ranges of key parameters were determined,such as the type of the deflector,the inclination angle of the inclination angle of cone discγ,and the structural parameters of the compound hole etc.（2）Simulation and experimental study on the working process of cone diversion type seed metering device.Through edem simulation analysis,it is determined that the arc-shaped deflector with blade spacing of 90°is the optimal type,and the angle of cone disc is 60°and the left edge of the opening of compound hole is inclined inward.The optimal combination of the structural parameters of the compound hole is obtained by the quadratic orthogonal rotation combination test:The opening angle of the right end face of the holeαis 59.9°,the height of the right end face of the hole L₁is 5.6 mm,and the length of the bottom of the hole L₂ is 17.2 mm.The results of bench test show that when the working speed of the metering device is 6～12km/h,the qualified rate of the metering device can reach more than 98%,the damage rate is less than 0.4%,and the error is less than 2%compared with the simulation test results,the rationality of structural design and the accuracy of simulation optimization are verified.（3）Study on the performance of cone diversion type seed metering device under vibration condition.EDEM simulation software was used to simulate the action process of seed metering device under vibration condition,the test results showed that when the working speed,vibration acceleration and vibration frequency increase,it has significant influence on the different working process of seed metering device.The results of orthogonal vibration bench test show that the order of influence of test factors on seeding accuracy is vibration acceleration,working speed and vibration frequency;when the vibration acceleration is less than 0.63g and the vibration frequency is more than 4.28Hz,the qualified rate of the metering device can reach more than 95%,and the variation coefficient of grain spacing uniformity can reach less than 20%.Field tests have shown that when the operating speed of the seed metering device is 6～12km/h,the qualified rate can reach more than 82%,the missing rate is less than 15%,and the multiple rate is less than9%,which satisfies technical requirements of precision seeding.