Theoretical investigation of turning ability of two-machine sowing aggregate

Abstract

It is purposeful to increase the efficiency of the 80-100 hp tractors (traction class 1.4) in sowing agricultural crops by increasing the working width of the technological part, using wide-span sowing machine- and-tractor aggregates. However, their movement characteristics on the turning strips in many respects determine their technical and economic performance, as a whole. It has been found out by the conducted research that a motivated choice of the parameters of wide-span sowing machine-and-tractor aggregates allows them making manoeuvres of turns on the turning strip in an optimal mode, which promotes reducing the length and time for turns by 4.5-11.2 % and the width of the turning strip by 4.9-12.1 %. In order to improve the turning ability of a two-machine sowing aggregate, it is desirable to apply ballasting (i.e., installation of additional loading) of the front axle wheels of the tractor. Thus, additional loads with a mass of 180 kg, installed on it, can reduce the turning radius of the aggregate. The most noticeable result of ballasting is achieved, when the turning angle of the driven wheels of the tractor is greater than 0.32 rad. At the maximum value of the control action (α = 0.5 rad) the reduction in the turning radius of the aggregate, due to ballasting the front axle of the tractor, is 0.8 m (i.e. 15 %). It has been theoretically established that, in case the speed of the movement is increased from 1.0 to 3.0 ms-1, the turning radius of the unit tends to decrease. Such a result is because the increase in the drift angle of the rear wheels of the tractor outstrips the increase in the drift angle of the tires of its front wheels.