Study On Key Structural Parts Optimization Of NC Machine Tool For Water Chamber Head And Deflection Compensation Of Ram

As the key components of nuclear power steam generator and other equipments,water chamber head is the interface between steam generator and other components such as nuclear reaction pressure vessel,with the complex shape,it is very difficult to process.Overcoming the technical difficulties of efficient processing and developing a special numerical control machine for water chamber head processing is the guarantee for effectively promoting the serialization and batch production of the third generation nuclear power equipment in China.At present,large vertical lathe,floor milling and boring machine and other general machine tools are often used in combination with positioner to realize the processing of water chamber head at home and abroad.It has many organizational links and long production cycle,the consumption of processing and testing equipment and auxiliary equipment is very high,and the accuracy is difficult to guarantee.For the problems,an efficient processing solution of NC machine tool for water chamber head is proposed in this dissertation.Aiming at the common problems,structural optimization of key parts and deflection compensation of slider are studied to improve the comprehensive performance.The main research results are as follows:(1)A high-efficiency NC machine tool for the nuclear power water chamber head is proposed.Aiming at process requirement and existing problems in the processing of water chamber head,structure layout of the NC machine tool for water chamber head is put forward.Static and dynamic characteristics of the machine are obtained,the optimization space of the key parts such as the cross beam and the weak links of the machine tool are determined using finite element analysis,which lays a foundation for the structural optimization of the key parts such as the cross beam and the deflection compensation for the ram.(2)A cross-beam under multiple load cases topology optimization method based on functional section decomposition is proposed.Aiming at the lightweight requirement of cross-beam structure and problems existing in traditional topology optimization methods,the multi-condition stiffness evaluation function of beam is established,the weight factors of each working condition are determined according to the deformation of the beam,the two main load bearing functional sections are analyzed by two dimensional topological optimization,combining the two-dimensional functional cross section analysis and initial model optimization,the topology structure of cross-beam is improved,and the lightweight design of cross-beam is realized.(3)A size optimization method of cross beam considering fatigue life is proposed.Based on topological optimization of the beam,the corresponding relationship between the mechanical parameters and the life of the material under the asymmetric cycle is deduced to ensure beam reliability.The life of the beam with 99.9% reliability is calculated by finite element analysis,and then the maximum stress of the corresponding life when the reliability of the component is 99.9% is deduced.The dimension optimization research is carried out with the maximum stress as the constraint condition.On the basis of guaranteeing the reliability of the beam,the lightweight is further realized.(4)An innovative design and optimization method of A-axis component structure based on TRIZ theory is proposed.Aiming at the problem of insufficient stiffness of A-axis assembly,this thesis synthetically utilizes the theoretical knowledge of mechanics,mechanical design,manufacturing technology and so on.Based on TRIZ theory,an improved scheme which can significantly enhance the local stiffness of A-axis assembly is found,and size optimization is adopted to further improve its stiffness,narrow the gap of joint surface,so as to meet the requirements of the industry.(5)A deflection compensation method of swinging ram is proposed.Aiming at the problem of the swing ram deflection,the mechanical model of ram deflection and compensation under the influence of both stroke and swing angle is established.Through simulation analysis,the curve of the relationship between ram deflection and its stroke and swing angle is obtained.The deflection compensation method of the swing ram is put forward,deflection compensation force of ram with attachment is obtained and the corresponding compensation system is designed.