Preliminary Research On Design Approach Of Full-Toroidal Traction IVT

By torque split method and combination of a full-toroidal variator, an epicyclic gear train and a fix-ratio gear, the full-toroidal traction IVT is capable of changing the reduction gear ratio up to plus infinite (when forward drive) or minus infinite (when backward drive). In other words, the output axle of the IVT can undergo the running condition from one direction revolution to reverse revolution via geared neutral state. This is why the IVT (Infinitely Variable Transmission) is denominated. Due to excellent fuel economy and driveability, and other features such as simple configuration, low cost and high torque transfer capability, it has attracted much attention of researchers and manufacturers abroad and at home, and is expected to be a new generation of automotive transmission. For the purpose of grasping working principle and design theory of the new type transmission, and establishing basis for self development of the technology, the following work is conducted in this thesis: 1. The developing history, research status of the full-toroidal traction IVT are investigated, and its working features and application situation are also analysed based on the comprehensive literature review. 2. The different power flow and efficiency of possible IVT configuration are compared from each other. And an improved structure scheme is proposed which is beneficial to the recirculating power reduction and efficiency improvement by power split method. 3. As the core constituent, the variator is studied in detail by kinematic and dynamic analysis. The refined kinematic relationships of the roller are deduced and parametric study is then conducted. With the dynamic model establishment, the simulation analysis is followed, the specific design process of the traction drive is summarized. The above studies also provide theoretical base for determination of IVT control parameters. 4. The control principle and torque control process of the full-toroidal traction IVT is analysed. The control strategy of IVT and the integrated control of IVT with engine are studied preliminarily. In the end of this thesis, futher research work needed to do is indicated.