Research On Tribological Behavior Of Brake Shoe During Emergency Braking In The Deep Mine Hoist

Disc brake is an important part of deep mine hoist,and its emergency braking performance directly affects the safety and reliability of deep mine hoist braking.In the process of deep mine hoisting,the characteristics of high speed,heavy load and large distance lead to the coupling effect of brake shoe vibration,friction heat and stress in the process of high speed and large specific pressure emergency braking,which leads to the uneven distribution of brake shoe thermal stress and friction deterioration under vibration effect,which seriously restricts the emergency braking performance of deep mine hoist.Therefore,studying the emergency braking tribological behavior of the brake shoe of a deep mine hoist has important theoretical significance to improve the safety and reliability of the brake of the deep mine hoist.In this paper,the performance parameters of the brake shoe are obtained through experiments;combining the finite element method,mechanical dynamics method and tribological theory,a brake disc-brake shoe multi-field coupling analysis model is constructed,the vibration law of the brake shoe during emergency braking is explored,and the thermal stress distribution law of the brake disc and the brake shoe during emergency braking under the effect of vibration and the law of the influence of lifting parameters are revealed;through the emergency braking experiment between the brake shoe and the brake disc,the friction deterioration behavior of the brake shoe under the condition of multiple cycles of emergency braking and continuous braking of the motor out of control is revealed.The results show that: the vibration of the brake shoe is mainly in the Z-axis direction,and the high-frequency vibration and thermal stress of the brake shoe are gradually increasing along the rotation direction of the brake disc.The thermal stress of each brake shoe is symmetrical along the center of the brake disc.The stress concentration occurs on the sliding in side and sliding out side of the friction area of the brake shoe.Lifting speed,lifting quality and lifting acceleration will all affect the thermal-stress of the brake friction surface,but they are mainly affected by the lifting speed.The deterioration behavior of the brake shoe under multiple cycles of emergency braking is manifested as severe sliding wear,and under continuous braking conditions,it is manifested as sliding wear and adhesive wear that gradually increases with the braking time.