Coordinated structure of cylinder envelope line of two side face of planetary gear tooth

A coordinated structure of cylinder envelope lines of two side faces of a planetary gear tooth, comprising: after determining a planetary gear tooth width B according to a diameter of the planetary gear and a root circle size, geometrically expressing the positions and shapes of the front side faces and rear side faces of all planetary gear teeth by using two datum cylinders with parallel axes and having equal diameters, the axes of the two datum cylinders being parallel to center lines of the planetary gear teeth; in a cross-section of a top portion of a planetary gear tooth, a local projection of a datum cylinder adjacent to a front side face of the tooth appears at a bottommost portion of a projection of a front side face of the planetary gear tooth, and a local projection of a datum cylinder adjacent to a rear side face of the tooth appears at an uppermost portion of a projection of the rear side face of the planetary gear tooth. A quantitative mathematical relationship exists between a center distance L of the two datum cylinders, diameters d 0 of the datum cylinders, widths B of the planetary gear teeth and a planetary gear tooth face inclination angle λ at a pitch circle of a tooth root.