Substantiation of deck parameters of rotary threshing device

The damages of corn grain during threshing depend on many factors, the main of which is timely removal of grain from the threshing chamber what depends on the design of the deck. The functional parameters of the deck in self-propelled combines and stationary threshers used for threshing of seed corn have been studied. Studies of factors affecting the separation process of a mixture consisting of grain and other parts of corn cobs in the threshing chamber were carried out. It has been proved that the shape, size and layout of the deck holes have the greatest impact on the timeliness of the output of the threshed corn grain from the threshing chamber. In this case the deck should consist of three parts of different lengths: 1) a part of the deck of the chamber of the primary damage of the integrity of the cob grain structure; 2) the deck part of the main threshing chamber; 3) the deck part of the finish threshing chamber. The evaluation criteria for choosing the lengths of the deck parts are the average of the double ratio of the linear dimensions of the corn grain of the six main subspecies and the maximum length and diameter of the cobs of 65 main varieties cultivated in Russia. The ratio of the lengths of the first two sections of the deck should correspond to the Fibonacci golden section – 1.618 and the double ratio of the linear dimensions of all three sections – 1.29. The studies have evaluated the effect of the shape of the holes: round, round lunate, square, rectangular, and hexagonal. At the same time, the pattern of holes on the hexagon and the square and the square holes, additionally, at an angle 45 o to the rotor axis was studied. The feasibility of using round holes in the deck with a diameter of at least 10...14 mm has been established. As a result of using the deck of the proposed design, the conditions for timely removal of threshed grain from the threshing chamber with a reduced probability of damage are created.