| A large population of our country, lagging road traffic facilities, as well as poor safety performance are responsible for frequency traffic accidents. With safety belt being the most effective vehicle passive safety protection device, it will make a great difference in the accidents. Currently, the researches of vehicle safety belt mainly focus on the simulation analyses of the damage states of the different parts of dummy body that safety belt system causes, basing on passengers restricted system, applying dynamics of multi-rigid bodies, less research is focus on structural capability of retractor of safety belt. By emergency locking retractor, this paper analyzes the parameters of locking performance of belt-induction and vehicle-induction, and analyzes the structural strength of retractor bracket and makes some optimizations to improve the emergency locking performance and performances of constraint and counteracting load.Firstly, this paper introduces the development history of vehicle safety belt and the current technology state of domestic and overseas enterprises. Meanwhile, this paper analyzes the types, applications and grasps the mechanism and working principle of emergency locking retractor which is currently widely used. Analyzed the national standard of the vehicle safety belt, we can acquaint with locking performance and structural strength of safety belt retractor.Secondly, the kinetic parameter models of the belt-induction and vehicle-induction locking mechanism of safety belt retractor have been built. For belt-induction locking mechanism, draws a conclusion that the parameters of the spring stiffness, the initial amount of compression, and the distance of force worked significantly influence its locking acceleration through analyses of product examples. By applying MATLAB to optimizing model parameters, the superior solution satisfying the locking conditions can be found. For vehicle-induction locking mechanism, the theoretical method of derivation is applied to instances. It is found that the change of inclination angle of inner surface of vehicle-induction arm do not have much effect on locking deceleration.However, the groove angle of vehicle-induction seat is the key. This paper sets a limit to groove angle of vehicle-induction seat, providing a reference to the design of vehicle-induction mechanism.Finally, this paper introduces the failure forms of strength for retractor and draws aconclusion that the structural strength of the bracket plays an crucial role on safe stability of the retractor assembly. Consequently, the results of the finite element analysis of retractor model which is analysed by ABAQUS, show that initial rupture failure region of bracket is the area close to the bolt hole.Combining with analysis result and engineering experience, this paper uses the means of local shape change and adding stiffener to the bolt hole and other large deformation regions, to get an optimal scheme of higher strength bracket. At the end of last chapter, a briefly discussion has been taken about the failure forms of strap, D-ring, anchorages, buckles and other structures of safety belt system.This paper focuses on the research of retractor in both locking performance and structural strength, aiming at improving the safety performance of safety belt and decreasing the possibility of the damage of occupants as vehicle passive safety failure. |
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