The rationale for the curvilinear shape of the working body for layered subsurface tillage

Abstract

The larger the cross-sectional area of the formation can be processed in a single pass, the less energy is needed to carry out the process. The cross-sectional area of the treated formation is determined by the perimeter of the working body. The circle of all figures of equal perimeter has the largest area. It is advisable to make the working organ ring-shaped. When designing a ring on the plane of the smallest cutting force, an ellipse is formed. From the point of view of physical mathematics, the ellipse is the best curve possessing the minimum property. The optimal shape of the working body is an elliptical ring. The parameter of the ellipse corresponds to the angle of soil displacement in the longitudinal-vertical plane. The elliptical working body carries out the crumbling and separation of the layer with the removal of more solid macroaggregates of soil on the surface and the erosion-hazardous particles that remain inside the formation in the gap between them. Stresses on the working body are determined by interaction with the soil. On the base of the ellipse, the normal stress caused by the backing of the soil layer acts, and the pressure of the cutting edges of the working body affects the cylindrical surfaces. The intensity of stresses arising on the surface of the cylinder is determined on the internal crack of an elliptical shape located in a solid body under the action of a load. The greatest intensity of stresses is localized at the ends of the minor axis of the ellipse, and the smallest at the ends of the major axis. As the cracking angle increases, the stress intensity increases, and then decreases. With an elliptical shape of the working element, the stress intensity zone is wider than that of the circular cutting edge, while deformation of stretching and bending is created in the zone of lateral rounding, which is absent in the plane, and the traction resistance is reduced by 0,5 ... 1,3 kN. The degree of crumbling of elliptical working organs is 87,1 ... 98,5 % of fractions up to 50 mm, combing 1 ... 2 cm, reduction of erosion-hazardous particles 15...22 %.