摘要：舵机作为飞行器控制系统的执行机构，其寿命随飞行任务的完成而终结，属于典型的一次性机械零件。大功率传动使得舵机体积质量与承载能力之间的矛盾更加突出。分析某滚珠丝杠舵机大负载力矩下的破坏形式，确定螺母和拨叉为提高舵机承载能力的关键部件。首先，结合一次性机械设计理论，采用有限元分析方法，对影响螺母承载能力的4个关键因素进行计算，仿真数据与理论模型及实际破坏形式高度吻合，进而明确各关键因素对螺母承载能力的量化影响程度，并给出结构优化方案。其次，应用结构超静定理论，将拨叉悬臂梁结构优化成超静定结构，在输出特性不变的前提下，大幅提高其强度和刚度，明确剪切及挤压破坏为拨叉的主要失效形式，并给出强度计算校核方法。最后，将结构优化设计方法用于某型号舵机研制，经性能测试，满足全部性能指示，证明基于一次性机械设计理论的结构优化设计方法在滚珠丝杠舵机中应用的有效性。%As the actuator of flight control system, its life ends with the completion of flight mission, so it belongs to the typical disposable mechanical elements. High power drive of actuator makes the contradiction between volume weight and carrying capacity more serious. By analyzing the failure mode of ball screw actuator sustaining heavy loading moment, the nut and fork are determined to be the critical components for improving the actuator carrying capacity. First, combining the disposable mechanical elements theo⁃ry, the finite element method is applied for calculating the four key factors which affect the nut carrying capacity. The simulation da⁃ta is highly consistent with the theoretical model and actual failure mode, and then the quantitative influence degree and the struc⁃ture optimization scheme are provided. Secondly, using statically indeterminate structure theory, the fork adopts statically indetermi⁃nate structure instead of the cantilever beam, which greatly increases its strength and stiffness under the condition of the same out⁃put characteristics. Then make clear that the shear and extrusion failure are the main failure mode of the fork, meanwhile, the strength calculation method is given. Finally, the structure optimization design method is applied to actuator development, by per⁃formance test, and over⁃all properties are satisfied, which proves that the structure optimization design method based on disposable mechanical elements design theory is efficient for ball screw actuator.
