Analysis of the work process and designs of threshers of combine harvesters
The article analyzes the process of threshing the cut stem mass with direct-flow and axial-rotary threshing machines. A brief analysis of modern grain harvesters is presented. The imperfection of the designs of threshing and separating devices with low nominal productivity is noted, which is due to the insufficient intensity of the threshing drum in direct-flow threshing machines and high specific energy consumption in axial-rotary ones. A significant influence on the threshing process and, first of all, on the nominal productivity and specific energy consumption of the threshing drum intensity indicator, determined by the ratio of the drum circumference of the threshing organs to the drum diameter, has been established. So, a combine with a 150 hp engine, in which the threshing drum had an intensity index of 33.3, the nominal productivity for harvesting rice was 34 t/h, which is 2.9 times more than that of a combine with a threshing drum, the intensity index which is 16.7. With an increase in the intensity index of the threshing drum from 12.6 to 16.7, the specific energy consumption for the threshing process decreased by 1.3 times. An axial block-rotor device has been developed with a high separating capacity, which can be used as a straw separator for a direct-flow threshing machine with a threshing drum with a high intensity index. A scheme of a direct-flow thresher with an axial block-rotary straw separator is presented.