The main body of underground conveying system of coal mine is rigidly connected because of the structure of carrying scraper with chain. In the process of conveying, down from coal winning machine mining coal stone volume and density range, especially in the process of coal mining stone falling for the impact of the gravity load chain and even the entire inevitable damage mechanical transmission system, the working face of coal transportation and uninterrupted work bring huge hidden trouble, and then affect the completion of tasks of owner to mining. The torque limiter installed between the motor and the reducer in the power section can not only protect the whole mechanical system by timely and efficient skidding absorption of excess energy when impact load occurs, so as to ensure the uninterrupted mining of coal mine, but also facilitate the owners to maintain and control the cost of equipment.