Technological assessment of seeding machine transmission

Among the various groups of agricultural machinery, a special place is occupied by seeding machines, which implement one of the most important operations in crop production technologies. The technological performance of the seeding machines (first of all, the seeding rate) largely depends on the characteristics of their transmissions, which ensure the transfer of the power flow from the supportdrive wheels to the metering units. Thus, the optimization of the performance of the transmissions of seeding machines is a rather urgent task, the solution of which has the prospects for implementation in industrial production. Moreover, in the design of grain seeders, the change in the seeding rate can be quite smoothly adjusted by changing the length of the working part of the sowing machine coil, therefore this problem is most significant from the point of view of the operation of rowcrop seeders. Due to a number of technical and technological shortcomings, infinitely variable transmissions have not yet received widespread use in the design of seeding machines, therefore, most of them are still equipped with stepped transmissions, the main components of which are gearboxes or gearboxes with replaceable gear wheels (sprocket mi). Traditionally, the «optimality» of the choice of transmission is carried out by visual imposition of the theoretical (reference) and projected series of gear ratios. However, an objective assessment of the convergence of such results can be carried out only on the basis of the use of quantitative estimates. In this study, it is proposed to use a criterion (conditionally - the criterion of «nonoptimal» transmission), which, in fact, reflects the average deviation of the actual gear ratios from the theoretical ones. Moreover, since in this case the definition of the geometric mean value is inapplicable (since some particular indicators can be zero), the criterion of «nonoptimal» transmission was defined as the arithmetic mean value of the relative deviations of the gear ratios, expressed as a percentage. The proposed criterion, in spite of its simplicity, makes it possible to determine the most rational combinations of gears (sprockets) of gearboxes or gearboxes of transmissions of seeding machines by enumeration or programming.