Influence of dynamic irregularity of paddy machine worktable oscillations on grain mixture separation

Paddy machines are widely used to separate various bulk products, but until now there have been no engineering methods for their technological calculation and there is no consensus on the physical nature of the process. Separation of grain products and other bulk mixes usually takes place under conditions of limited movement of material particles, which have different geometric and physical and mechanical properties and also interact with each other in a random manner. This makes it difficult to model the grain mix separation process. The aim of the study is to increase the efficiency of the grain mix separation process on the paddy machine by reducing the dynamic unevenness of the worktable oscillations. After studying the scheme of forces acting on various design elements of the paddy machine, in particular the worktable, fixing and supporting wheels, as well as the bearing, differential equations were obtained for the plane-parallel movement of the working surface and for the movement of the elements of the paddy machine during braking of the table during reciprocating motion. A program for numerical integration of the equation of the table motion was developed, the implementation of which showed that the highest values of angular velocity occur at the beginning of the acceleration of the table and at the end of its braking, when the speed corresponds to the synchronous frequency of rotation. During the research, it was found that the wear of the supporting surfaces cannot exceed 0.25 mm. It was also found that during the first 480 hours of operation, the wear on each side of the support frame was 0.2 mm and for the total period – 0.96 mm on each side. Therefore, the total wear on both sides was 1.92 mm. At the stage of the first 480 hours, the work of the table was stable, but after 720 hours of operation, whipping began, which negatively affected the efficiency of the separation process. Therefore, the improvement in the design of the paddy machine, which is possible taking into account the recommendations developed, causes a known reduction in the contact forces that occur in the case of interaction between the carrier and the table, as a result of which the wear of the contact surfaces is inevitably reduced.