Dynamic brake characteristics of disc brake during emergency braking of the kilometer deep coal mine hoist

Abstract

Dynamic brake characteristics of disc brake during emergency braking of the kilometer deep coal mine hoist were investigated in the present study. The theoretical model of dynamic brake torque of disc brake during emergency braking was given to explore dynamic brake torque properties of disc brake. The three-dimensional thermo-mechanical coupled finite element model of brake disc–brake shoe was established to explore thermo-mechanical characteristics of disc brake during emergency braking. Effects of effective mass, hoisting acceleration and deceleration, and maximum hoisting speed on dynamic brake torques, equivalent von Mises stress, and temperature fields of disc brake during emergency braking were presented. The results show that the evolutions of brake torque, equivalent stress, and temperature of disc brake present fluctuating characteristics. The dynamic brake torque shows the largest change amplitude during emergency braking in the hoisting stage of constant speed. The largest equivalent stress and temperature are both located near the third brake shoe along the rotational direction at each side. An increase in effective mass causes overall decreases in the peak values of brake torque, equivalent stress, and temperature during emergency braking. Increases in hoisting acceleration/deceleration and maximum hoisting speed cause the increases in the maximum equivalent stress and temperature during emergency braking as compared to the slight decrease in the maximum brake torque.

Effect of Vibration on Emergency Braking Tribological Behaviors of Brake Shoe of Deep Coal Mine Hoist

“…The brake shoe has the density of 1788 g/cm 3 , an elastic modulus of 1031 MPa and Poisson's ratio of 0.23. The DSC differential scanning calorimeter is employed to measure the specific heat capacity of the brake shoe, and the evolution curve of specific heat capacity versus temperature is shown in Figure 1a.…”

“…Mining deep coal resources with a buried depth greater than 1500 m is a major development strategy in China. The hoisting mechanism for a 1.5-km-deep coal mine exhibits characteristics of large inertia and vibration as compared to that of a 1-km-deep coal mine [2][3][4]. When safety hazards, such as overspeed and the loss of control of the motor (when the motor continues to provide traction torque when it should be shut down at the end of hoisting), occur in the multi-rope friction hoist of a 1.5-km-deep coal mine [2], emergency braking between the brake disc and the brake shoe, with conditions involving high speed and high specific pressure and vibration [3,5,6], easily causes emergency braking tribological behaviors (uneven distributions of thermal stress and friction deterioration) of the brake shoe.…”

“…The hoisting mechanism for a 1.5-km-deep coal mine exhibits characteristics of large inertia and vibration as compared to that of a 1-km-deep coal mine [2][3][4]. When safety hazards, such as overspeed and the loss of control of the motor (when the motor continues to provide traction torque when it should be shut down at the end of hoisting), occur in the multi-rope friction hoist of a 1.5-km-deep coal mine [2], emergency braking between the brake disc and the brake shoe, with conditions involving high speed and high specific pressure and vibration [3,5,6], easily causes emergency braking tribological behaviors (uneven distributions of thermal stress and friction deterioration) of the brake shoe. Therefore, the failure of emergency braking in the brake shoe greatly affects the braking safety and the reliability of the hoist, and even causes braking impact, rope skidding and overwinding accidents, which causes serious and deadly accidents, such as well destruction in the coal mine and human death.…”

“…According to the thermo-stress fields and vibration characteristics of a brake shoe during emergency braking ignoring vibration, Olesiak et al [9] investigated the temperature field distribution of the brake shoe. Wang et al [3] studied the effects of hoisting on the equivalent von Mises stress and temperature fields of a brake shoe. Wang et al [13] explored the effects of braking parameters on thermo-stress fields and flutter characteristics, respectively, without coupling them together.…”

Design and experimental study of electrical and mechanical brake for mine hoist

“…Tests showed that the iron powder composites have the best effect. Da Gang Wang et al [7] studied dynamic characteristics of the brake of a kilometer mine hoist during emergency braking, the three-dimensional thermo mechanical coupling finite element model of disc brake shoe is established, and analyzed the influence of temperature field on emergency braking. Masoomi et al [8] proposed to use a friction material with thermal modulus to improve the braking performance of the hoist.…”