弹药装填系统用蜗式推送链动力学分析

推送链机构是一种新型直线伸缩机构，可将弹药从一个位置快速推送至另一位置，具有推送距离长、收回状态占用空间小的优点。该机构采用蜗式链盒存储单向链，能够在有限空间中存储最大数量的链节，实现大距离的推送。为了分析链轮多边形效应和啮合冲击对单向链的动力学特性和推送平稳性的影响，建立了单向链从链盒中抽出过程及与链轮啮合过程的动力学模型，同时，将单向链伸出部分简化为多弹簧阻尼系统，推导出单向链推送过程的动力学模型。借助数学软件MATLAB，采用龙格-库塔法，对推送链机构的整体动力学模型进行数值仿真。仿真结果表明：在推送过程中，将单向链从蜗式链盒中拖出的抽出力随时间震荡减小至0，链轮对单向链的拨动力由剧烈震荡过渡至平稳波动，且单向链的推送速度波动较小，该机构具有良好的推送平稳性。通过试验测量，验证了所建立动力学模型的准确性。

Dynamics Analysis of Helicoid Pushing Chain Mechanism for Automatic Ammunition Loading System

The helicoid pushing chain mechanism is a novel telescopic mechanism used to push objects from one position to another one rapidly.It occupies a minimal amount of space in the contact status. In constrained space the helicoid chain case adopted may store as many links as possible for acquiring a long telescopic distance. In order to analyze the influences of polygon effect and meshing impact on the dynamic properties and pushing stability of the unidirectional chain, the dynamics models are established for the processes of extracting the unidirectional chain from the helicoid chain case and it meshing with the sprocket. Meanwhile, the extended part is simplified as a multi-spring-damping system, and the dynamics model of pushing process is deduced. The full dynamics models is numerically simulated by using MATLAB software and Rung-Kutta method. The simulation results show that the drawing force acted on the unidirectional chain in the chaincase drops down to zero concussively over time, and the change of the thrust force transits form drastic oscillation to smooth fluctuation. Besides, the pushing velocity of the chain is nearly constant during the pushing process. Hence this mechanism has an excellent pushing stability. In addition, the established dynamics models are verified by the experimental measurement of the pushing velocity.