Based on the analysis of working principle of half toroidal CVT,and guided by Hertz contact theory,the contact stress calculation formula of half toroidal CVT was established. Taking a company’s prototype for example,the change laws and influencing factors of the contact stress were discussed.Studies showed that in the case of constant axial force, the contact pressure and stress are larger and relate to the location of the contact point,the contact position is closer to the axis of the cone,the contact ellipse’s major axis is longer,and the contact ellipse’s minor axis is smaller.The contact stress decreases with the increases of torus radius,cavity radius,and half cone angle.The contact stress have high sensitivity with cavity radius,and low sensitivity with torus radius and half cone angle.If the contact type of the cone disk and the roller is line contact,contact stress can be reduced significantly.The research results can provide theoretical reference for design of half toroidal CVT.
