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Acta Armamentarii ›› 2018, Vol. 39 ›› Issue (5): 841-850.doi: 10.3969/j.issn.1000-1093.2018.05.002

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Analysis of Headspace in Locking Mechanism with Locking Lug Shifting in Considering Part Deformation

LUO Shao-min, XU Cheng   

  1. (School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China)
  • Received:2017-09-20 Revised:2017-09-20 Online:2018-06-22

Abstract: Headspace is a typical assembly requirement in automatic weapon assembly, which directly affects the performance and safety of automatic weapon. To research the headspace under actual working condition, a calculation method of part deformation based on finite element analysis is put forward, and an analysis model of assembly tolerance considering deformation is established. For the assembly accuracy of machine gun with locking lug shifting, an analysis model for locking mechanism is established, the assembly precision change of headspace in considering deformation caused by temperature is analyzed, and the influence of temperature on headspace is studied. The influence of deformation on headspace in counter-recoil and the influence of part deformation during the launching process are investigated. The results show that the distribution center of headspace is obviously offset, and the distribution range contracts with the increase in temperature after considering the deformation induced by temperature. The headspace is decreased by 0.015 mm in considering deformation at barrel chamber temperature of 300~600 ℃. Considering the deformation caused by the impact in counter-recoil, the headspace is increased by 0.02 mm. Elastic deformation of parts is 0.14 mm during the launch process. The transverse fracture of cartridge case will not happen when headspace is between 0.38~0.47 mm, but, will occur when headspace is 0.47~0.48 mm. Key

Key words: automaticweapon, lockingmechanism, assemblytolerance, headspace, loadeffect, deformation

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