| Drum brake, which plays a crucial role in driving safety, is wildly used in freight andpassenger car. Improving the braking efficiency and reliability have always been the emphasisof the researches. There are many problems such as braking unstable, braking deviation andwearing unevenly in the using of drum brake, so it is necessary to do some research on thestructure and brake process of it, especially on the improvement of brake performance. Recentyears，a kind of floating drum brake has been improved form the ordinary one. Though ahigher performance it got, the research on it is still initiatory because of it’s short appearance.So, in order to study the contact status of the friction plate, some equations are built in thisarticle through kinematic analysis method to calculate the contact angle of friction plate. Bythe equations both the contact law of ordinary and floating drum brake is compared and theinfluences of different design parameters are studied. Finally an FE model is built to simulatethe mechanical properties of the drum brakes during the actual work process, and the validityof theory is confirmed by the simulation. The main research contents are listed as follows:(1) The equation of contact angle for both drum brake are built and the further analysisfound that the downside of the friction plate has a bigger contact angle than other places, sothere will be a poor contact status in that region. To solve the problem, the floating brakeimproved the contact law by adjusting the first contact point, so that both ends of the frictionplate has a same contact angle and will contact with brake drum at the same time.(2) To some extent, the floating drum brake could offset the influence of eccentric error.The friction plate could always keep a best contact status by floating along some directions.However, the contact status of ordinary brake influenced by eccentric error more deeply and itis disadvantageous to the braking stability.(3) The FE analysis showed that the pressure distribution of contact surface for leadingshoe of radial floating drum brake is more uniform than that of ordinary one, but thedistribution of trailing shoe still need to be optimized. Further more, the braking efficiency ofradial floating brake is higher than ordinary one. |
