This device is mainly designed for trucks. The device acts on the bottom of the car and applies emergency braking by pressing down the friction group. The friction group is extruded from discarded ordinary car tires. The friction coefficient of the external friction group is increased by squeezing and folding the waste tire to form a flower-shaped concave and convex structure. Using large friction coefficient retention and ground friction braking force to cooperate with the internal friction of the drum brake to play an auxiliary braking role. The design can improve the truck braking effect, reduce the braking distance, prolong the tire wear cycle, improve safety. In this paper, the control principle of the device is analyzed and the structure is designed. The stress and shape variables of the main stressed parts are simulated and analyzed. The simulation results show that it can basically meet the design requirements.