Structure optimization design method for ball screw actuator based on disposable mechanical elements design theory

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 theory, the finite element method is applied for calculating the four key factors which affect the nut carrying capacity. The simulation data is highly consistent with the theoretical model and actual failure mode, and then the quantitative influence degree and the structure optimization scheme are provided. Secondly, using statically indeterminate structure theory, the fork adopts statically indeterminate structure instead of the cantilever beam, which greatly increases its strength and stiffness under the condition of the same output 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 performance 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.