某埋头弹机枪退壳系统设计与动力学分析

Dynamic Analysis and Design of the Ejection System of a Cased Telescoped Ammunition Machine Gun

为了同时解决埋头弹枪的退壳与首发装填可靠性问题,在埋头弹机枪设计时,提出了在弹壳滞留槽上加工阻挡斜面的办法.要求该斜面可以阻挡首发装填的埋头弹,却不能阻挡后续射击中被推出弹膛的弹壳.针对弹链与埋头弹之间、埋头弹与弹膛之间的接触情况,建立了接触碰撞模型,并将其代入多体动力学方程,通过多组取值对比分析,求解出符合首发装填及后续退壳要求的滞留槽内底面高度为0.3 mm.依据仿真求解得到的参数调整埋头弹枪物理样机,测得了滞留槽高度分别为0、0.3 mm时,枪机框复进的速度曲线.试验证明,计算得到的滞留槽内底高度在实际应用中可靠.

In order to ensure simultaneously the reliability of the ejection and the first round loading of the cased telescoped ammunition machine gun,method of processing the blocking slope on the detention support was proposed in the design of the cased telescoped ammunition machine gun.It was required that the slope could block the first loaded cased telescoped ammunition,but would not the cartridge case from being pushed out of the chamber in the subsequent firing.In view of the situation that there were gaps between the ammunition belt and the cased telescoped ammunition,as well as between the cased telescoped ammunition and the chamber,a contact collision model with gaps was established,and it was applied into the multi-body dynamic equation.Through the comparison and analysis of multiple sets of values,the height of the inner bottom of the detention support meetings the requirements of the first round loading and subsequent cartridge case ejection was calculated,which was 0.3 mm.By adjusting the physical prototype of the cased telescoped ammunition machine gun according to the parameters obtained from the simulation solution,the velocity curve of the bolt carrier with the height of the inner bottom of the detention support being 0 and 0.3 mm respectively was measured.The test shows that the calculated inner bottom height of detention support is reliable in practical application.