The present IVT (Infinitely Variable Transmission) is built around a full toroidal variator where high forces acting on low inertia characterize it as a smooth and responsive system. Because of the complex and frequent motions of the rollers, the variator dynamics plays a key role in the transmission. Furthermore, the IVT requires detailed description of the interactions between variator, driveline and hydraulic for an optimum control development. Accurate variator dynamic investigation is therefore a vital element of the modeling requirement.
A complete one-roller model of a full toroidal variator including mechanic and hydraulic parts is presented in this paper. The roller movement is described in response to a torque and a speed ratio change. A six-roller model is then introduced to highlight the difference between the rollers behavior.