IMPROVEMENT OF DIGGING SHARES OF ROOT HARVESTING MACHINES BASED ON RHEOLOGICAL MODEL OF SOIL STATE

Harvesting of root crops is one of the most important technological processes, which accounts for more than 30% of total costs in the performance of all technological operations. The most difficult technological process during the potato harvesting is the process of soil separation, which consists in the destruction of soil clods, and further their separation on the web elevators. It was established that the ability of soil to separate is determined by its state. These factors affect the ability to use potato harvesters and determine their efficiency. On loamy and clayey soils, the separation efficiency is reduced. The separation of the soil becomes much more difficult with increased its moisture. In order to intensify the process of destruction of the soil layer it is proposed to form in it destructive stresses along the entire path of movement along the working surface of the share. This can be achieved by creating a share with a curved working surface. The design of share working surface is based on the Coulomb-Mohr strength theory, according to which material failure occurs at various combinations of the main normal compression stresses and tension. At the same time, it is taken into account that the compressive strength of the soil is 3-7, and with a shear of 2.4-4.3 and more times, exceeds the tensile strength. Therefore, it is advisable to induce tensile stresses in the soil layer. Field trials have shown that replacing a flat share on a potato harvester with a new share with a curved working surface increases the efficiency of its technological process by intensifying the process of destruction of the soil layer.