High-torque variable-speed drives of rotor drive mechanisms and drive wheels of the combine
We offer a number of developments, aimed at the application of High-Torque Variable-Speed Drives in farm machinery. We also represent projects for rotor drive mechanism of the grain combine and its driven units.
Transmitted power – Np = 30 kW; Combine speed – V = −20 … 20 km/h; Wheel rotation irregularity factor – δ = 0; HTVSD service life – [L]h = 1800 hours.
The grain combines are multiaggregate machines with high demands to stability and smooth adjustment in the wide limits of kinematical and dynamic parameters of aggregates, due to which in the first models of combines the friction V-belt variable-speed drives were used for the drive mechanism of drive wheels and rotor.
Friction variable-speed drives are not applied in modern combines because of the growth of the drive power, and the absence of High-Torque Variable-Speed Drive (HTVSD) compels the designers to use hydrostatic power drive (HPD) for drive wheels and mechanical gear-box (GB) in the rotor drive mechanism. The electric transmission is not applied because of high values of dimension, weight and cost.
HPD ensures necessary technical parameters, but has high cost, low efficiency coefficient (about 80%) and requires special professional maintenance.
The rotor drive via GB is not considered to be satisfactory because of the following main reasons:
rotor speeds are discrete, that’s why they are not always optimal for the threshing process;
it is impossible to change the rotor speed in motion, because in order to change gear it is necessary to stop the combine, which reduces productiveness.
The application of HTVSD for the rotor drive mechanism and drive wheels will improve the technical characteristics of combines.
In the course of definition of kinematical and power parameters of HTVSD, the grain combine “Don-2600” was selected as the basic model.