Efficiency of mine locomotive braking on prolonged slope by pulsating braking torque

Abstract

The purpose of the work is to develop a mathematical model and study the process of braking a mine locomotive with a disk brake on a prolonged slope at a nonlinear braking moment. Research methods. Forced oscillations of elements of the wheel-motor unit (WMU) of the mine locomotive in the process of braking with the disc brake were investigated by the methods of differential calculus and mathematical modeling. Integral transformations of Laplace and Hankel were used in the analytical solution of the differential equation of thermal conductivity in cylindrical coordinates using the theory of generalized variables and the similarity method. Findings. It has been proven that the pulsating sinusoidal braking torque created on the axis of the wheel pair, which is equal to the sum of the constant component and the amplitude of oscillations of the variable component, multiplied by the sine of the product of the number of periods of the sinusoid per one turn of the wheel pair by its angular coordinate, provides higher braking characteristics of a mine locomotive on a prolonged slope than a constant braking torque. It is shown that the maximum absolute value of the track slope, at which the temperature of the working surface of the brake disc will not exceed the permissible value during a prolonged descent for the specified track length, speed and mass of the train, with a pulsating braking moment will be greater for different states of the rail track. The originality. For the first time, a mathematical model of mine locomotive braking on a prolonged slope with a disc brake which creates pulsating braking moment on the wheel pair axis, that depends on its angular coordinate, taking into account the nonlinear dependence of the clutch coefficient on the relative sliding was developed, on the basis of which the efficiency of a disc brake with a multi-sector disc in comparison with a disc brake with a homogeneous disc on a prolonged slope at different track states is shown. Practical implementation. The research results make it possible to establish with the selected parameters of the disc brake with a multi-sector disc and the disc brake with a homogeneous disc the maximum absolute value of the track slope, at which the temperature of the working surface of the brake disc will not exceed the permissible value during a prolonged descent for the specified track length, speed and mass of the train at different conditions of the rail track.