Research On Assembly Precision Analysis And Control Of Automatic Weapon

Assembly precision is an important embodiment of the assembly quality in automatic weapons products,which is directly related to the production efficiency,function realization,equipment maintenance and shooter safety.With the improvement of automatic weapon product's quality and reliability,the analysis and control on assembly precision has become one of the focuses in automatic weapon design.The paper focuses on the assembly precision of automatic weapon based on the background of the '12th Five-Year basic scientific research project',in according to provide the theoretic basis and implementation technology of automatic weapon tolerance design and improve product assembly precision and the exchange rate.The main contents of this paper are as follows:Aiming at the manual filing in automatic weapons industry,the general characteristics in automatic weapons assembly are summarized and the requirements for the product assembly precision are discussed from the product characteristics of automatic weapons,the analysis contents of assembly precision are reduced.Finally,the current situation in the assembly of automatic weapon and the main cause that resulted in the manual filing are analyzed based on the practical investigation.The tolerance analysis model based on 3D model with Jacobian-torsor method is put forward.Taking automatic weapon with locking lug shifting as the study object,the assembly precision of headspace is carried out,and the 3D tolerance analyses are implemented using VisVSA software.To research headspace under actual working condition,analysis method of assembly analysis is put forward as well as the transfer model of assembly error considering working load is developed according to the working characteristics of automatic weapon,and tolerance analysis model is established.The calculation method of deformation based on finite element model is proposed.Taking a type of machine gun with locking lug shifting as the study object,the assembly precision change of headspace considering deformation caused by temperature and load is analyzed,and the influence of different temperature on the headspace is studied,as well as deformation effect in counter-recoil and firing.The influence of assembly precision on performance of automatic weapon are researched through modeling and simulation.The relation between the accuracy and performance of automatic weapon are researched through simulation analysis.The integration method for assembly precision analysis and the motion accuracy is proposed.Taking the assembly accuracy and ejection movement of an automatic weapon as an example,the influences of the accuracy of parts on the cartridge position and velocities of ejection during the ejection process are studied.The control scheme of assembly precision based on assembly sequence is proposed for headspace assembly of automatic weapon with bolt rotating,and the analysis model for assembly precision under different assembly sequences is established,in order to analyze the effect of assembly sequence on headspace assembly.The control scheme based on combination measuring is proposed for headspace assembly of automatic weapon with locking lug shifting,and the combination principle of components,the tolerance redistribution scheme and non-filing method in final assembly are determined.The engineering verification of control schemes on weapons with bolt rotating and locking lug shifting are conducted.The engineering verification of assembly precision control on bolt rotating can realize the target.The static assembly experiment,firing experiment and interchange experiment of locking lug shifting weapon are implemented to validate the combination measuring method.