Synthesis method for compact dual-clutch transmission with four DOFs gear mechanism

The design of dual-clutch transmission with multi-degrees-of-freedom (DOFs) is a good solution to increase in number of gears and a wider range of gear ratio in the limited space and weight. This article proposes a novel synthesis method for scheme design of the dual-clutch transmission with four degrees-of-freedoms gear mechanism. First, the shift sequences considering the path of power flow and shift logics are analyzed based on the degrees-of-freedom model, abstracted from the degrees-of-freedom of the schemes. Second, the schemes of gear-pair and shaft, defined as the scheme that ignores the arrangement of synchronizers, are derived from the basic configurations, defined as the schemes of gear-pair and shaft that contains only one of each type of the variable connections, and the numbers of each type of the variable connections. Finally, multi-parameter, including synchronizers arrangement and gear ratios, is optimally designed for the results of synthesis. The seven-speed dual-clutch transmission schemes with four degrees-of-freedom and two shaft systems are taken as an example to explain this synthesis method. In addition, this article helps to obtain a deeper understanding of the systematic design of other fixed gear transmission schemes, such as automated mechanical transmission, automated mechanical transmissions with electric torque supporting, and even some novel multi-input transmissions.