The Design Of Plot Wheat Breeding Harvester And Simulation Research Of Threshing-transporting Performance

Wheat breeding harvesters in China exist the problem of single operation function, low production efficiency, poor technology level, large labor intensity.Combined with breeding agronomic requirements of field experiment district, a plot wheat breeding harvester adapting to the breeding mode in China was designed. The material flow simulation inside threshing device was researched, based on the discrete element method, and the structure and operation parameter of threshing device was optimized. The study was studied mainly from the following aspects.(1) Design a plot wheat breeding harvester. According to the planting model and relevant technical conditions of field breeding wheat, a plot wheat breeding combine harvester was designed by structure comparison and theoretical analysis,in order to the job requirements of gain high efficiency, low loss, low grain retention and low impurity rate. The machine was mainly consist of cutting device, feeding device,threshing device, separation and cleaning device. The machine has compact structure,low power consumption, simple operation. It can complete the operation process of cutting, threshing, cleaning, collecting, straw returning all at once.(2) Research a axial conical roller threshing device. Threshing device is the core component of wheat breeding harvester. The structure design vitally impact on job result of the whole machine. According to the functional requirements of high threshing rate, low breakage rate, no hysteresis, a threshing device was designed by analysis structure characteristics and working performance. It was mainly consist of conical threshing roller, up cover with rasp bar, under smooth cover, winnower.(3) Analysis the movement process of mixture materials in threshing device through simulation. Based on the idea of discrete element method, simplifying the threshing material to a mixture of wheat grain and stem, establish a discrete element model of material object, using EDEM software simulation threshing device inside the movement process of mixing material. Design three different types of threshing component model(nail tooth, short rasp bar tooth, combined tooth), watching the movement of the model under the mixed material process, and analysis the grainnumber change and the stress distribution, the results show that after simulation the combined tooth conical roller threshing device inside the fewest of grains, more grain number is less, shows that the cylinder model to take off the best performance.Choose the model further analysis of threshing device inside the trajectories of grain,short stalks, quantitative research is the actual process of migration.(4) Optimize the operation parameters of use roller threshing device. To choose a combination of tooth threshing device virtual simulation experiments, selecting feeding amount lose clearance and drum rotational speed, as the main factors influencing the take off lose performance, to cover the damage rate of residual rate,simulation experiment of single factor evaluation indexes and choose the optimal level of various factors of orthogonal test design, further through the extreme difference analysis and variance analysis to get the optimal operation parameters combination, namely the feed rate of 0.4 kg/s, roller speed of 1600 r/min, take off clearance is 14 mm, combination of tooth threshing device of best performance.