ТРИВАЛІСТЬ МАНЕВРУ ПОВОРОТУ КОЛІСНОГО ТРАКТОРА В НЕУСТАЛЕНОМУ РЕЖИМІ ПРИ СУМІЩЕННІ РОЗГОНУ І ГАЛЬМУВАННЯ

The article discusses the process of performing a turning maneuver of a wheeled tractor in an unstable mode of movement under conditions of combined acceleration and braking. It is shown that when a tractor is working with mounted, semi-mounted, or trailed equipment, a significant part of the working cycle is devoted to such maneuvers, especially when performing loading, transport, and technological operations in a confined space. It has been established that the duration and radius of the turn significantly affect the length of the trajectory, the dynamic loads on the running gear components, and the total duration of the tractor's working cycle.A step-by-step structure of the turn is proposed, which begins and ends at zero speed and with the steered wheels in a neutral position. The main phases of the maneuver are considered: turning with simultaneous acceleration and increase in the turning angle of the steered wheels, steady turning with a minimum radius, and turning with braking and a decrease in the steering angle. For theoretical analysis, the assumptions of uniformly accelerated acceleration and braking of the tractor and a constant angular speed of the steering wheels are made.Analytical dependencies were obtained to determine the duration of an unstable turn, the angular velocity, and the average turning radius for tractors with a single steerable axle and an articulated frame. An approximate empirical formula is also proposed, which can be used in the early stages of design or in engineering calculations of performance. The results of the calculations were compared with experimental data, which confirmed their sufficient convergence. The obtained dependencies allow refining the methodology for determining the duration of the working cycle and can be used to improve the efficiency of wheeled tractors.