Based on the analysis of the factors which affect the braking force of a heavy vehicle drum brake driven by cam

the applied force at leading and trailing hoof and cam profile are systematically investigated.The relationship of the center distance between cam and roller and the force arm of the applied forces is studied as well as the relationship of cam rotation angle and the applied force.Finally

the influence of cam profile on the applied force at braking hoof is analyzed under three typical stages of worn shoes

the quantitative relationship between cam profile and applied force is given as well.It is shown from the study that the optimization of cam profile can great improve braking efficiency and vehicle safety.