The present application belongs to the field of gear design, and particularly relates to a design method of a drum-shaped modification curve of
gear tooth direction, comprising: 1) constructing a whole C 2 smoothly continuous double circular-arc spline drum-shaped modification curve; 2) obtaining the coordinates of the common tangent point F i of the i-th double circular-arc segment of the double circular-arc spline drum-shaped modification curve; 3) constructing a multi-element nonlinear equation set; 4) obtaining an initial solution by solving the
linear term of the equation set, and iteratively calculating the accurate solution of the multi-element nonlinear equation set; and 5) obtaining the drum-shaped modification curve of the
gear tooth direction according to the accurate value of the
intermediate variable chord tangent angle of the i-th double circular-arc segment. The drum-shaped modification curve of the
gear tooth direction obtained by the present application adopts segmented low-order interpolation, can avoid the "Runge" effect of high-order interpolation, and has good properties of the first and second order derivatives of the drum-shaped curve. The curve has high fitting accuracy, is continuous and smooth, reduces the
impact and vibration in the
gear transmission process, improves the
tooth surface contact state, and improves the
gear transmission performance.