Structure Design And Research On A Run-flat Tire

Along with the development of the high way and ascension of motor vehicle speed,traffic accident caused by tire burst is serious. Run-flat tire（RFT）which is able to make thecar run a comparatively long distance safely after tire burst, avoiding the casualties andcanceling the spare tire which increases the car weight, have been equipped by some new cars.It is aimed at design a run-flat tire fix on standard rim, which can support the car’s weight andrun to repair pit to change tire without tire-separating and tire-rolling when airless.This thesis introduces RFT development history and current situation in the world. Aninternal support of run-flat tire is designed fixed on standard rim according to the worlddesign requirements for RFT, considering installing space restriction and tire deformation etc.On the basis, the stress state of RFT in smooth running process and burst moment areanalyzed.First of all, according to national standards for tire and rim design requirement, thespecification of tire and rim are selected. Then, the radial tire structure is worked out using thenatural balance figure method.The outline dimensions of inner support fixes on standard rim are limited by followingfactors: installation space and tire deformation restrict the inner support biggest outlinedimensions; continuing running ability under low air pressure restrict the smallest. Under theconsideration of various restrictions to inner support outline dimensions, its structure isdetermined and all the support is locked by heel blocks.By using finite element analysis software ANSYS to aid design of inner support, thematerial is determined, the region bearing small force is optimized in order to reduce mass,and the best locking location is found. The specific structure and dimension are obtained then.To know the RFT force state in the process of running, the state is simulated by usingdynamic finite element software ANSYS/LS-DYNA. It is proved that the inner support can belocked in rim slot and bear the car body load reliably. Finally, the simulation of RFT falling toground when burst is carried out. The result shows that the inner support will not damageunder the instant impact load.