The article presents the results of a study of a high-performance grain cleaning machine for the preliminary cleaning of grain pile with a closed aspiration system. The fl ow regimes of the "air-grain pile" mixture determined by the Reynolds number and the bulk concentration of particles are established. As a result of the modeling, further directions for improving pneumatic systems of grain cleaning machines were determined: the cleaning effi ciency of the Е 0 fraction of pure grain from light impurities, shriveled and crushed grain reaches 82%, the output cleanliness of the grain was 93.7%, and the loss of full grain to waste P z = 0,017%. The average speed of the air fl ow in the separating channel is U = 7.12 m/s, its coeffi cient of variation across the width of the separating channel is v = 12,7%. The results of the experimental data confi rmed the adequacy of using mathematical modeling of the air fl ow in the pneumatic system of a grain cleaning machine to substantiate the basic parameters of the pneumatic system.

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The article gives the results of the comparative tests of wear-resistance and reliability of metal-cutting tools equipped with carbides of ВК8, Т5К10 ,Т15К6, КНТ16 and ТН20 brand marks undergoing linear turning of test cylinders steel-faced with Np-30KhGSA wire. Intense hardness, structural imperfection and ridgeness of the metal coating make its further mechanical processing more difficult. Experimental technique is based on the cutting temperature persistence. Optimum cutting data for the cutting bits equipped with carbides of ВК8, Т5К10, Т15К6, КНТ16 and ТН20 brand marks have been found. Comparative tests proved that wearresistance of the instruments equipped with carbides Т5К10, Т15К6 and КНТ16 is 1,4-1,8 times higher than of those equipped with ВК8 carbide.

The purpose of this work is a mathematical description of sieve frame structural and technological parameters necessary for the implementation of the technological process model of a grain cleaning machine operation. The paper presents the results of the study of the grain cleaning machine sieve frame operation. A kinematic study of a flat swivel multi-link mechanism of the grain cleaning machine sieve frame was made. The method of determining the coordinates of the sieve frame nodal points was developed to calculate their speed. Structural and technological parameters of the mechanism were also studied.