摘要:Analytical studies concerning the issues of heap supply for harvester-thresher cleaning, composition of tailings and the amount of grain are presented in the paper. The urgent problem of increasing the separation of air-sieve cleaning of modern combines is outlined. The schematic structure of the combine thresher is presented. The calculation of the grain mass quantity which is received for cleaning from the threshing group, the straw rack and finish threshing device is conducted. The visual image of cleaning load depending on supply is shown. According to the calculations it is possible to predict the loading of cleaning with small grain heaps depending on the total supply of grain mass to the thresher for combines of various classes. The technical solution to improve the cleaning system of a combine harvester is suggested and economically evaluated in the paper.