Justifi cation of the parameters of an electromechanical transmission for a tractor of traction class of 0.6-0.9 traction class and coordination of traction characteristics
The parameters of electromechanical transmission for the tractor of 0.6-0.9 traction class are selected based on the analysis of traction and hitching characteristics of the complete machine. The authors have made theoretical calculations of the operating characteristics of the prototype tractor with an internal combustion engine and the tractor layout with an electric drive, traction calculation of the prototype tractor and the tractor layout, and calculation of the characteristics of the electric drive and electric motors. For the calculations, a six-speed manual variable gearbox was selected. The initial data for performing the calculations were obtained from the results of tractor traction tests in the North Caucasian machine test station. Two profi le backgrounds of the support base were selected: a fi eld prepared for sowing (fallow) and stubble. As a result of research, it was established that a tractor-model designed on the basis of the self-propelled chassis of a pulling class 0.6 to. 0.9 with capacity up to 50 kW on the “Fiel d prepared for sowing” background reaches the greatest towing effi ciency (0.53) with the 15 kW electric motor and the greatest drawbar pull (5.78 kN) with the 18 kW electric motor. On the “Stubble” background, for 15, 18 and 22kW electric motors, the pulling effi ciency is 68%, but the tractor layout with the 22kW electric motor can develop the maximum drawbar pull of 11.35kN. The maximum pulling power of 16.7 kN is observed in the prototype tractor with an internal combustion engine. Therefore, the 15-kW electric motor can be the only most suitable substitute for a combustion engine by traction effi ciency.