Design And Experiment Of Self-propelled Green Onion Combine Harvester

China is the largest exporter of Chinese onion,but at present,the harvest of Chinese onion is mainly artificial and the mechanization level is low.In view of the problems of high wound rate and low harvesting efficiency of onion harvesting machinery on the market,the theoretical calculation and structural design of key components of onion combine harvester were carried out based on the agronomic and physical and mechanical characteristics of onion planting in China.The computer was used to simulate and analyze the multi-level layered excavation shaking device and the secondary cleaning device.The overall structure of the onion combine harvester was determined,the key technical problems in the process of onion combined harvesting were solved,and the development of onion industry was promoted.The main research contents of this paper are as follows:（1）The multi-stage layered excavation shaking device was designed,and the rotary tillage soil separation device,excavation shovel and multi-stage cleaning device were theoretically analyzed.The working mechanism of multi-stage layered excavation shaking device can reduce the excavation resistance is expounded.The simulation model of onion ridge was constructed by using discrete element technology,and the single factor simulation experiments of rotary tillage soil separation device and digging shovel were carried out.The feasibility of rotary tillage soil separation device design was verified,and the influence of rotary tillage knife shaft inclination angle and digging shovel into the soil angle on the operation effect was analyzed,which provided theoretical basis for the design of digging soil shaking device of onion harvester.（2）The flexible clamping and conveying device was designed,and the theoretical analysis was carried out on the support feeding device,clamping and conveying device,secondary cleaning and cleaning device and reversing device.The operation mechanism of onion clamping and conveying was expounded,and the feasibility of clamping and conveying device was verified.The kinematics simulation of the secondary cleaning and cleaning device was carried out,and the motion trajectory was plotted.The influence of the crank speed on the secondary cleaning and cleaning device was analyzed,which has reference significance for improving the research of the secondary cleaning and cleaning device.（3）The collection and unloading device was designed,and the overall structure and transmission system of the self-propelled onion combine harvester were designed combined with other key components.A field experiment was carried out on the prototype.The operating speed,digging shovel angle,and cleaning and conveying chain transmission speed were used as experimental factors,and the impurity rate and damage rate of onion were used as evaluation indexes to obtain the optimal parameter combination:digging shovel angle of 30°,cleaning and conveying chain transmission speed of 0.50 m/s,and operating speed of 0.36 m/s.In the field experiment,the impurity rate of onion was 1.59%,the damage rate was 2.77%,and the operating efficiency was 0.13 hm~2/h.The reliability of the prototype was verified to meet the requirements of onion harvesting.