Design And Experiment Of The Longitudinal Axis Threshing Device For Rice

The land of rice-growing area in southern hills and mountains are small and flat, as the high yield of rice become a trend, the gradual increasing of requirements for rice-threshing machine, makes rice harvesting machinery face greater challenges. The traditional longitudinal axial flow rice-threshing devices for wet corps are easy to congestion and high threshing entrainment loss rate and fragmentation rate when the large feeding quantity, the feeding spiral of the threshing cylinder was improved and experimented on the threshing device, the main works and conclusions are as following:1.Designed the overall structure of the longitudinal axial flow rice-threshing test bed, explained the working principles of the threshing device, calculation and analysis of all the assembly units for the threshing device, and designed 9 feeding spiral with different parameters through the analysis of the feeding spiral working principle, to get technical parameters of high feeding quantity threshing.2. Preliminary discussion for follow-up tests, an experimental research on the biological natures of rice are carried out, and analyzed the average plant height, Grass-Valley ratio, 1000-grain weight, moisture content, and other parameters of the experimental rice plants. We made a performance evaluation experiment on threshing cylinders with different feeding spirals, under the condition of large feeding quantity and the evaluation factors of smooth delivery of threshing and threshing effects, selected the high-performance feeding spiral with three heads 270mm long and 240mm pitches.3. In order to increase the feeding quantity and optimize the effect of threshing apparatus, on the selected best feeding spiral, the regression orthogonal rotation design test was carried on, the threshing device structure and motion parameters are optimized. The result showed when the cylinder rotation speed reaches 800r/min, the guide plate lead angle reaches 23.7°, threshing gap 20mm, the grain crushing rate were 0.1% and unthreshed rate were 0.069%. what meets the relevant national industrial standard requirements. Based on the partial regression coefficient test of the regression equation, the analysis on the basis of the response surface method of evaluation index to experimental factors shows that the effect order of grain crushing rate are the rotation speed of the longitudinal axial flow cylinder, threshing clearance, and the guide plate lead angle, and the impact order of the under-threshing loss rate are rotation speed of the longitudinal axial flow cylinder, the guide plate lead angle, threshing clearance. At the same time, the results suggests that with the drum rotation speed increasing, grain crushing rate are increased while the unthreshed rate were reduced; with the threshing gap increasing, grain crushing rate were reduced while the unthreshed rate were increased; with the guide plate lead angle increasing, the grain crushing rate were reduced and the contrary of the unthreshed rate.