Research on soft-start characteristics of hydro-viscous drive for scraper conveyor under different start-up conditions

In order to study the soft-start characteristics of scraper conveyor under different working conditions, the mathematical model of each link of controllable starting transmission, the bearing capacity, and the torque model of hydro-viscous drive were established. The influences of load start-up speed and friction coefficient on soft-start characteristics of scraper conveyor were revealed. The load torque, oil film bearing capacity, oil film thickness, and sliding power curves of hydro-viscous drive under different load start-up conditions were obtained. The results show that the oil film thickness decreases with the increase of soft-start load, and the asperity torque and bearing capacity play a major role. With the change of load, the optimal start-up speed case was different. The load matching effect of S-curve start and sinusoidal start is better under heavy load condition, and the matching performance of linear start and parabolic start is better under light load condition. By controlling the start-up speed and acceleration reasonably the scraper conveyor can start smoothly under different loads. The research results provide theoretical basis for the matching of dynamic performance and the design of hydraulic control system in the soft-start process of controllable starting transmission.