Vibration Reduction Research On Three-wheeled Motorcycle

The vibration of three-wheeled motorcycle is the key issue that influences the ride comfort and safety, how to solve this problem has become the urgent need for the manufacturers. Based on the theory of vibration and FEA, this paper takes the BY150 three-wheeled motorcycle as the research project to do vibration research, mainly solving the problem that most three-wheeled motorcycles have strong vibration with the common speed, so as to improve the ride comfort of the three-wheeled motorcycle.Firstly, in order to understand the actual vibration and quantify the size of vibration, this paper tests the vibration acceleration on several key positions of three-wheeled motorcycle under the static condition and the driving condition. And also measure the damping effect using the rubber connecting the engine and frame. The test result shows the engine vibration strongly, and the vibration amplitude of the handlebar and pedals are controlled well in the range of full speed accept having vibration peak in 2500～4000r/min; using the rubber to reduce the engine vibration have obvious effect in the range of common speed, and also have resonance in 42-67Hz.Secondly, in order to have a deep research and analysis on the vibration situation, including the specific forms and vibration frequency of BY150 three-wheeled motorcycle, this paper integrate application of Pro/E, HyperMesh and ANSYS software, the finite element model of the frame is established. Based on finite element method and experimental modal analysis, the free modal analysis is done, and the former six natural frequencies and corresponding modal shapes are analyzed. Considering the impact of the excitations from engine and road to the modal characteristics of body, a preliminary assessment of the dynamic characteristics of the frame is discussed, which improve a theoretical basis for design improvement of the frame.Thirdly, in order to understand the stiffness characteristic of the frame, the stiffness of the finite element model of the frame is analyzed, which provide a design reference for the modification of the frame with appropriate stiffness. Then, according to the structure characteristic and the finite element analysis, local optimization of the frame is conducted and the improvement scheme of frame structure is proposed.Fourthly, through comparing the modal characteristics and the stiffness characteristic of the improved frame and the former frame, the vibration of the improved structure is predicted.Lastly, in order to validate the effect of the improved structure, the vibration of the improved structure and the former structure on three-wheeled motorcycle are compared under the static condition and the driving condition by vibration test. And also measure the damping effect using different connection between the engine and frame. Comparison test results show that the vibration comfort is improved, but owing to the modification of the frame and the structure size is changed, using the spring to reduce the engine vibration is better than rubber.