Abstract
It is important for railway vehicles to get compatibility between curving performance and running stability. Utilizing independently rotating wheels may be an effective solution. The EEF bogie proposed by Frederich in 1990th shows good curving performance making use of gravity restoring force generated by the tread gradient of independently rotating wheels. However, the bogie gives rise to a kind of hunting motion as the vehicle running speed increases. In this paper, an effective modification of the EEF bogie which solves the hunting motion is mentioned. The solution is to incline both wheel axles while adjusting tread gradient of each wheel. In this paper, the EEF bogie with inclined wheel-axles is firstly proposed and analytically evaluated by modeling and MBD simulation. Since the newly proposed bogie has complicated structures, the precise modeling of the bogie is mentioned in detail. From the result of linear stability analysis, proposed bogie can dramatically improve the high speed stability as compared to the conventional EEF bogie. In addition, the proposed bogie has excellent curving performance in tight curved section equivalent to the conventional EEF bogie. As those results, it is possible to achieve both high speed stability and high curving performance utilizing the proposed bogie unit in the vehicle.
