Optimal Design Method for Mountain Bike Rear Suspension Mechanism

Almost all kinds of rear suspension systems of mountain bikes are analyzed and classified into three categories:one-hinge rocker-arm configuration,rocker-arm driven four-bar mechanism and connecting rod driven four-bar mechanism.Based on the rear suspension mechanism drawing of mountain bike(MTB)in existence,the mapping relationship is built between the ratio of the axial force of the shock absorber to the vertical force of the rear axle and the angle displacement of the rear axle,and its influence on the riding vibration comfort and maneuverability is further analyzed.Taking the typical MTB as example,the different mapping characteristics of force ratios of different forms of rear suspension mechanisms are compared,and the conclusion is that the rigidity of four-bar mechanism is lower than that of the one-hinge rocker-arm configuration.On this basis and through analysis,the design parameters influencing the performance of the rear suspension system are found to be the length of the side link,the length of the connecting rod and the pivot position of the absorber and the frame.Then,the parameters of a typical MTB rear suspension system are optimized,with the force ratio curve of the system as the cost function,the rod length and absorber position as design variables, the space of the practical configuration as limitation.Finally,a dimension synthesis method of the rear suspension is acquired.