山地自行车后悬架机构优化设计方法

Optimal Design Method for Mountain Bike Rear Suspension Mechanism

分析山地自行车后悬架主要类型,将其归纳为单铰结构、摇臂驱动四杆机构和连杆驱动四杆机构三类。在归纳现有山地自行车后悬架机构图谱的基础上,建立减振器所受轴向力与后轮轴所受垂直力之比与后轮轴角位移的映射关系,探讨这种关系对骑行振动舒适性及操控性的影响。以典型样车为例,比较不同形式后悬架机构力比映射特性的差异,得到四杆机构后悬架刚度小于单铰结构后悬架刚度的结论。在此基础上,通过分析找出影响后悬架系统性能的设计参数为:连架杆长度、连杆长度和减振器与车架连接的位置,并以这些参数为设计变量,以实际结构空间限制为约束条件,以设定的力比曲线为优化目标,通过典型实例优化后悬架系统的设计参数,给出一种后悬架机构尺度综合方法。

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.