SELECTION OF A DRIVE SYSTEM FOR COMPONENTS OF A BLOCK-MODULE UNIT

Justification of a power transmission system for the working element of agricultural machinery requires identifying optimal principles for synthesis of its structure based on factors affecting the performance of its primary function. The purpose of this study is to improve the operational efficiency of agricultural machinery by developing and implementing a system of criteria for the informed selection of a drive type, ensuring reduced operating costs and increased reliability. The drive system of the tools included in a block-modular unit for pruning fruit trees was studied: EVR-1 and EVR-2 electric branch trimmers, EPS-1 and EPS-2 electric saws and EKR-1 electric brush cutter. For the final selection of the option of power transmission system to the working element, it is recommended to use the failure-free operation indicators as an additional preference criterion. As a result of the calculations, the types of drives were established depending on the transmitted power, the extension distance of the working element and the type of movement it performs: for EVR-1 and EVR-2 electric branch cutters, EKR-1 electric brush cutter, in which the working element performs a rotational movement and it is extended at a distance of no more than 4 m from the power source, a mechanical drive is advisable (availability factor 0.96; mean time between failures 192 motor-hours; recovery time 1.5 hours); at greater distances, up to 250 m, an electric drive with increased (200-400 Hz) frequency (0.97; 204 motor-hours; 1.2 hours) is preferable; at distances over 400 m, an electric drive with increased and industrial frequencies are equivalent; for EPS-1 and EPS-2 electric saws, which have a reciprocating working element and an extended reach of up to 10 m, a hydraulic drive (0.96; 246 motor-hours; 1.1 h) is recommended for any transmitted power. As the power decreases, it is recommended to extend the hydraulic drive’s range to 40 m. Increasing the working unit’s extension distance to 200-250 m makes a high-frequency electric drive (0.97; 198 motor-hours; 1.2 h) economically feasible.