中文摘要：

准确掌握汽车转向系统双十字轴万向节空间布置规律对车辆操作的平顺性和舒适性至关重要。运用Matlab对双十字轴万向节三轴共面和异面空间运动规律进行分析，绘制出轴间夹角、输入轴角度、相邻轴所成两平面之间的夹角等组合因素对双万向节传动比波动影响的曲线图。在CATIA中建立与理论推导相匹配的实体模型，并基于DMU运动分析进行仿真。利用传动比波动影响的曲线图对模型进行调整，验证了汽车转向系改进后的硬点布置的可行性。结果表明，相邻轴之间夹角的差异是导致传动比波动的主要原因。中间轴节叉相位角对传动比波动幅值有一定影响，但主要对传动比波动的相位有较大影响，提出了在转向系统设计时可以通过节叉相位角和硬点调整相结合实现转向的左右对称性。

英文摘要：

Having all the information of the spatial layout of double cross universal joints in a car＇s steering system is very important for ride comfort. It uses MATLAB to analyze the spatial motion law of the double cross universal joints. The three axles of the double cross universal joints can be coplanav or non-coplanar. Then it draws the curves of the influences on the change of the ratio of the double cross universal joints which can be caused by the change of the angle between axles, the angle of input axle and the angle between the planes of near two axles. Building solid models which match the theoretical derivation, and does the emulation based on the method of DMU. Adjusting the model based on the conclusion of the curves of the influences on the change of the ratio of the double cross universal jaints , and then acquires the layout of hard paints in the steering system after the adjustment. The results show that the main cause of fluctuations in transmission ratio is the angle difference between the adjacent shaft. The phase angle of double cross universal joints in intermediate shaft has a certain influence on the amplitude of fluctuations in transmission ratio, but mainly the phase angle has a great influence on the phase of fluctuations in transmission ratio. In the steering system design, the phase angle and the hard-point adjustment can be combined achieve symmetry in steering.