Research On Design Method For Beveloid Variable Ratio Pinion-sector Of Recirculating Ball Variable Ratio Steering Gear

The circulating ball variable transmission ratio（hereinafter referred to as "variable ratio"）steering gear can effectively alleviate the contradiction between steering sensitivity and portability.It can realize the variable ratio through the meshing transmission of rack and beveloid variable ratio pinion-sector,so as to meet the variable ratio steering requirements of vehicle "sensitive at low speed and stable at high speed".However,as the key component of the recirculating ball variable ratio steering gear,the beveloid variable ratio pinion-sector has the problems of difficult design and low investigate efficiency due to its complex tooth surface geometry.In order to realize the design of beveloid variable ratio pinion-sector accurately and quickly,based on the gear meshing principle,this paper puts forward the numerical analytical design method of beveloid variable ratio pinion-sector for circulating ball variable ratio steering gear,deduces the parameter equation of beveloid variable ratio pinion-sector tooth surface and the constraint equation to avoid undercutting and center phenomenon,designs the solution algorithm of beveloid variable ratio pinion-sector tooth surface point cloud,and carries out an example design,The effectiveness of the proposed design method is verified by simulation and test.The main research work of this paper is as follows:（1）Design method of beveloid variable ratio pinion-sector for recirculating ball variable ratio steering gearThrough the analysis of the forming principle of the beveloid variable ratio pinion-sector,based on the knowledge of analytical geometry and gear meshing principle,the numerical analytical design method of the beveloid variable ratio pinion-sector of recirculating ball variable ratio steering gear is proposed,the mathematical model of the beveloid variable ratio pinion-sector is established,and the parameter equation of the beveloid variable ratio pinionsector tooth surface and the constraint equation to avoid the undercut and tip phenomenon of the beveloid variable ratio pinion-sector are deduced in detail.（2）Algorithm and design example of beveloid variable ratio pinion-sector for recirculating ball variable ratio steering gearThe tooth surface point cloud domain of beveloid variable ratio pinion-sector is deduced,and the solution algorithm of tooth surface point cloud is designed based on MATLAB software.The design parameters of beveloid variable ratio pinion-sector without root cutting and tip defects are given,and the corresponding tooth surface point cloud is generated.Then,the solid model and virtual assembly model of beveloid variable ratio pinion-sector rack pair are efficiently established by CATIA software.Subsequently,the corresponding finite element model is constructed by ABAQUS software,and the effectiveness of the proposed design method is verified by the simulation analysis of the transmission performance of the beveloid variable ratio pinion-sector rack pair.（3）Sample preparation and test of beveloid variable ratio pinion-sector for recirculating ball variable ratio steering gearThe sample of beveloid variable ratio pinion-sector and rack pair is trial produced by NC milling,and the transmission ratio test device of beveloid variable ratio pinion-sector and rack pair is designed and built.The test transmission ratio curve is compared with the theoretical transmission ratio curve,and the transmission ratio error results verify the effectiveness of the proposed design method...