Analysis and refinement of design parameters of the machine-tractor unit based on the tractor K-744R-05

In accordance with the functional purpose of the designed tractor, the type and parameters of the transmission are selected according to the terms of reference. However, dynamic loading introduces adjustments to the parameters of the machine-tractor unit. For example, in the transport mode on the surface of the state of the amplitude-frequency characteristic of the tangential traction force of the tractor K-744P-05 at a regular speed υо = 3,6 m/s, the gear ratio of the transmission iт = 35,35, at a frequency ω = 8,0 S-1, the amplitude increases to 16.62 kN, accompanied by a «galloping» of the machine-tractor unit. The surface of the amplitude-frequency characteristic is obtained by calculation, and the transmission is adopted as a «stepless variator», limited by the gear ratio iт = 126,10 and iт = 20,30. This allows you to refine the amplitude of the oscillations between the nearest gear stages and adjust the gear ratios of iт value. The phase-frequency characteristics of the components of the dynamic component of the tangential pulling force are also calculated: inertial forces and forces from oscillations of the machine-tractor unit in the longitudinal-vertical plane. It was found that with the decrease in the center-to-center distance by 12,5 % (up to 2,8 m), the amplitude increased by 0,49 kN (2,9 %), and the amount of energy expended - up to 103,2 kJ / s, which is more by 14,46 kJ / s (14,0 %) than at the nominal interaxial distance l = 3,2 m. At the interaxial distance increased by 25 % (from 3,2 to 4,0 m), the amplitude decreased by 0,6 KN (3,6 %), and the amount of energy by 16,4 kJ / s (18,5 %). The increase in the phase delay of forces from oscillations of the machine-tractor aggregate in the longitudinally vertical plane from 45 to 59,9° reduces dynamic loading, and the reduction in the phase of inertial forces from 13,6 to 12,8° continues to support «galloping». After adjusting the transmission ratio of the transmission in the first gear of the fourth mode from iт = 35,8 to iт = 29,42, the regular component of the tangential traction force was decreased by 7,1 kN (17,9 %); total power consumption by 23,4 kW (9,7 %); hour fuel consumption by 5,2 kg / h; the oil consumption on the burn by 56 g/h. Simultaneously, the speed of movement increased by 0,77 m/s (21,6 %).

tractor, power inputs of the machine-tractor unit, dynamic loading, transmission, interaxial distance, amplitude-frequency and phase-frequency characteristics