Dynamics and Failure Analysis of the Process of Elevator Safety Gears Stopping the Car

The safety gears serve as an extremely important protective measure when the car is descending at an overspeed. However, in existing theoretical research, it has not been considered that after stopping the car through safety gears, the continued movement of the counterweight can lift the car again, triggering speed governor reset and potentially leading to the failure to stop the car. This makes it difficult to match the actual process of stopping the car and poses a huge challenge to ensuring the safe operation of the elevator. Therefore, this study introduces an elevator dynamic model that reduces the reeving factor of the elevator without sacrificing computational precision. It explores the evolving mass and stiffness variation law of the suspension ropes as the car and counterweight move, examines the asynchronous running characteristics of the counterweight and car motion state during the car stopping process, and identifies the conditions triggering the reverse pulling of the car. Subsequently, a multi-body dynamics mathematical model is constructed to simulate the elevator’s behavior during safety gear-induced stoppage, with equations solved through approximate methods. The reason for the failure of the safety gear to stop the car is systematically analyzed under the reasonable selection of components. Experimental findings confirm that the theoretical model proposed in this paper can accurately evaluate the dynamic characteristics of the safety gears stopping the car, and has wide engineering application value.