Research On The E-limiting Chart Used To Select The Modification Coefficient Of The Less-teeth Gear

As an important component and extension of conventional involute cylindrical gear, less teeth gear has larger transmission ratio and is more compact. Less teeth gear has the advantage of being a form of transmission with large transmission ratio and compact form. In recent years, it has been applied to wind power, electric vehicles and other industries. This paper is aimed at solving the problem of selecting the modification coefficient of less-teeth gear by designing its e-limiting chart.First, based on the basic theory of modified helical gear and the existing research results of less teeth gear, problems, such as sharpened teeth, meshing with backlash and meshing beyond pitch point have been studied thoroughly, and some relevant formulas have been deduced.Second, according to the need for selecting the modification coefficient of less teeth gear, all sorts of limits and quality index curves equations of the e-limiting chart have been deduced and collated.Third, taking unitized method, all sorts of limits and quality index curves equations are transformed to such ones, which have the only one variable of modification coefficient. So that it is convenient to write and program.Finally, MATLAB, which has powerful ability for calculation and plotting, is used for programming in this paper, and conveniently deals with the problems of equations solving and curves plotting during the process of e-limiting chart designing. The final design not only takes the helix angle into account, but also introduces equal center distance line, normal backlash and the function of geometric dimension calculating. Tests have proved that this e-limiting chart is simple, convenient, fast and accurate.