Abstract
Improvement of the screw working bodies for surface tillage is important for increasing the efficiency and quality of agricultural work. The purpose of the work was to calculate the design of the screw a working body for the surface cultivation of the soil from the compartment of the developable helicoid, which would perform the technological process with minimal resistance to plunging in the soil. The surface theory, analytical, and differential geometry were used to design the working body. It is shown in the paper that through a given spiral line, which is the cutting edge of the surface (blade), it is possible to draw developable helicoids with different inclinations of rectilinear generators. Designing the surface for the best plunging into the soil is important. It is established that the proposed working body is an alternative to the existing disc-type tools. It has been proven that for a long time, spherical discs for surface cultivation of the soil were fixed on a common shaft, which was installed on the unit with a certain angle between its axis and the direction of movement of the unit, which contributed to the plunging of the discs in the soil. It is confirmed that the disc-type tillage implements were improved, but this complicated the design of the unit since each disc received an individual axis of rotation. Studies have shown that this made it possible to additionally set the roll angle, that is, the deviation of the plane of the disc blade from the vertical direction, which improved the plunging of the disc in the soil and ensured more effective turning and mixing of plant residues. The proposed screw working body combines the simplicity of the design of the common shaft and the presence of the angle of attack and roll, which confirms its effectiveness in comparison with existing analogs. The necessary calculations were made, and the surfaces of the right and left courses were constructed with the designation of the necessary structural parameters. The application of the obtained results can simplify the design of the soil processing unit