Problems of process control for shifting gears on tractors without torque interruption

The article considers the problem of optimizing the process control for shifting gears on tractors without torque interruption. The opinion on the dynamics of process control for shifting gears is explained, it takes into account the occurrence of torque deficit in the shafts, when changing gear, and increasing of friction losses in spinning clutch. The formulas for calculating the dynamic parameters used in the mathematical model of the dynamics of the tractor when shifting gears without torque interruption are shown. With the help of the mathematical model developed in Scientific and Research Tractor Institute (NATI) for debugging the system of electro-hydraulic control of gear shifting process for CHN-6 tractor were calculated several variants of gear shifting. Particular attention is given to occurrence, development and completion of the power circulation process in the circuit of switched clutches, because the lack of circulation of power the majority of authors call the basis of optimal switching. The results of the calculations in terms of the circulation of power, failure to slipping of switching off the clutch and interlocking of switched on clutch are shown. Calculation results suggest that when the clutch of lowest gear is closed the torque growth in spinning clutch of switched on top gear causes an increase in friction losses of disks, which leads to a decrease in engine shaft speed and reduction of the tractor speed. The magnitude and duration of fall of the engine speed and the speed of the tractor are low, but due to a decrease in the speed of the tractor the moments of forces inertia are large enough and need to be taken into account in the calculations. In all experiments, where power circulation was present, it started earlier than top gear clutch created torque, which corresponds to the resistance movement. In all experiments, where power circulation was present, it ended as a result of reducing the pressure in the clutch booster of lower gear after its failure to spinning in the power circulation mode. The circulating power after the failure to spinning and clutch switching off is redirected to output shaft accelerating the tractor and accelerating the synchronization and interlocking of switched on clutch.

tractor, transmission, gear shiftng, power flow, spinning clutch, mathematical model