Design of a steering mechanism for the three-wheel tilting motorcycle

Abstract

There is a trend to develop three-wheel motorcycles because of their better stability and superior cornering ability compared to 1F1R (one front wheel and one rear wheel) motorcycles. The main purpose of this study is to establish a design process for the 2F1R (two front wheels and one rear wheel) three-wheel tilting mechanism and to reduce the turning radius to fulfill steering geometry in order to reduce the steering torque for a better handling feel. This research is divided into two parts: first, an existing steering tilting mechanism is selected as a design reference, and creative design methods are applied to set design constraints and requirements to facilitate a new mechanism design. A steering tilting mechanism is developed based on the design parameters of the steering mechanism and design objectives. Then Simpack software is employed to simulate handling tests on various routes and to verify the design model. The steering torque of the new mechanism is found to be much higher than that of the design reference. Therefore, the next step is to apply the Taguchi method to optimize the steering mechanism and to ensure that the parameter combination that satisfies the design objectives for the steering mechanism is selected. Finally, the route evaluation indexes are obtained from handling test simulations. From the results of the steering characteristics of the reference and research vehicle, the steering torque is found to be directly related to the response capability. Furthermore, the steering torque of the research vehicle is reduced by the optimization analysis using the Taguchi method, and the route evaluation indexes indicate that the vehicle's handling characteristics were improved.