Mechanical Design of In-Wheel Motor Driven Vehicles with Torque-Vectoring 2011-36-0132

Volatile oil prices and increased environmental sensitivity together with political concerns have moved the attention of governments, automobile manufacturers and customers to alternative power trains. From the actual point of view the most promising concepts for future passenger cars are based on the conversion of electrical into mechanical energy.

In-wheel motors are an interesting concept towards vehicle electrification that provides also high potentials to improve vehicle dynamics and handling. Beside aspects concerning the electric system (e.g. motor type, energy storage, and control strategy), there are also some open questions related with the mechanical design of in-wheel motor driven vehicles that need to be solved before series production.

In this work, the results of a research project being developed at the Institute of Automotive Engineering - FTG - of Graz University of Technology together with MAGNA Powertrain and MAGNA STEYR dealing with the design of an in-wheel motor driven vehicle belonging to the low segment are presented. These results address some of the major mechanical problems related with this kind of technology. Firstly the design requirements for the electric motors are determined based on the desired driving performance. In the second part, the suspension system characteristics are determined with the aim to reduce the negative effect of the increased unsuspended masses on ride comfort and driving safety. Afterwards, the mechanical integration of electric motor, transmission, braking system and suspension components into the wheel is described. Finally, the design of a torque-vectoring system based on the installed in-wheel motors and some simulation results obtained using a multibody simulation environment also developed at the FTG are shown.