Key Technology Study Of Safety Belt Retractor

The automotive industry has grown rapidly for nearly a century,especially in the past more than 10 years.Whether the volume of car production or its retention has created new highs,and with the advent of electric vehicles,in the next 3 to 10 years,car sales will create a high growth rate.Car safety problems always accompany with cars,and in this era of chasing car lightweight,high-speed development,Automotive safety systems will face unprecedented challenges.Our country’s traffic accident rate is ranked top in the world,of course,this is because our city planning and road’s demographic pressures,another one,also is the most important one,our country’s automobile safety performance and its safety equipment system develops slowly,that is,our technology generally lags behind.In particular,as the core protective device in the automotive safety system,safety belt,the research on its technology and even the basic technology is very lacking in university institutions and related enterprises.This situation not only makes the local seat belt quality generally low,but also in the case of micro-profits,it is still difficult to compete with foreign seat belts.Therefore,the research on the key technology of seatbelt must have universal significance on guiding the development of seatbelt.Firstly,this paper expounds the research background of seatbelt,that is,the development history of seatbelt and the research situation at home and abroad.And,This paper systematically and detailedly analyzes the main two seat belts,composite sensitive locking seatbelt and preloaded-limited force seatbelt,including the working principle and its technical details.It can provide the domestic seat belt R & D personnel the key to clarify its research technology and optimize the direction of improvement.This paper analyzes and extracts the relevant performance regulations and experimental requirements of the safetybelt’s key technology.On the basis of analyzing the requirements of the regulations,the paper analyzes and introduces several core technologies of the retractor.And combining the current status of the safety belt technology in the enterprise,this thesis puts forward the research emphasis—locking mechanism and force limiting torsion bar design technology.Secondly,this paper studies three key technologies mentioned above,that is,the belt acceleration sensitive locking mechanism technology,vehicle tilt and deceleration locking mechanism technology and torsion bar design technology of the limiting forceseat belt.First,this thesis established the dynamic model and the kinetic equations of the sensitive locking mechanism,and gained the solution of the equations.Applying the formula to a specific seatbelt for parametric research,using the MATLAB software to express the equations and study the relationship between the four key parameters of the equation,the spring stiffness,the spring preload amount,the distance of the spring center line to the spring to the rotation center of the inertial swing block,the moment of inertia of the swing block and the locking acceleration,the pulling length of the webbing during locking and the locking time,the relevant parameter design conclusions are obtained.Second,this thesis studied the tilt and deceleration locking mechanism.respectively,this thesis established the vehicle tilt locking mechanics model and the deceleration locking mechanics model in the two cases of without considering the friction and the quality of the car-sensing arm and making full consideration,and carried on more thorough discussion.Applying the conclusion to a specific seatbelt for parametric research,using the MATLAB software,thesis studied the relationship between the locking acceleration and the angle of the inclined groove of the vehicle sense seat,the locking length of the webbing,and made discussion on design method of the inclined slot angle of the vehicle sensing seat and the selection range and the range of the locking length of webbing.Third,making the force analysis on the force-limiting torsion bar of the force-limited seat belt,establishing the mechanical model,The elastic-plastic change and the corresponding torque of the torsion bar at different stages are analysed in this paper.After analysis,we chose the elastic range to design,obtained the section design formula of the force-limiting torsion bar,then given the specific working conditions and finished the instance analysis and design.Finally,specific to the research results above three key technology,the article carried out the experimental verification of the instance calculated,including the follows: the experimental verification of the locking acceleration of the belt acceleration sensitive locking mechanism,the experimental verification of oblique groove angle,deceleration and belt locking distance of the vehicle sense seat of the deceleration locking mechanism and the static torque test experiment and collision experiment for the limiting performance of the force limiting bar designed above for instance.Through these experiments,we verified the correctness of the established models.At the end of this paper,we summarized and analysed the shortcomings of the research,and on this basis the problems left behind,the development and research of seatbelt is prospected.This thesis focuses on the above three key technologies,in order to analyze theimpact of the key parameters on the safety belt performance.The theme and material of the thesis were taken from the enterprise of my internship,and the thesis was based on the in-depth understanding and research of enterprise’s products.Because the seat belt mechanism or working principle is less differentiated,that is,the way for the domestic and even foreign products in implementing the locking and force-limiting function are in much the same,except for individual details.Therefore,the research conclusions on the safety belts of different enterprises have great referential value and guiding significance for the design and change of the relevant parameters of the safety belt retractor.