面向结合面密封性能要求的装配连接工艺设计

为在产品设计阶段规划出满足密封性能要求的装配连接工艺,提出了一种面向结合面密封性能要求的装配连接工艺数字化设计方法.采用接触非线性有限元技术和弹性相互作用理论建立了螺栓组连接有限元模型,研究了螺栓预紧顺序、预紧力水平与结合面连接性能间的关系,构建了各螺栓预紧力大小与结合面压力间的关联模型,进而利用该关联模型,根据工况载荷下设备对密封性能的要求反求装配连接工艺.以发动机缸体缸盖装配连接为例,建立了发动机曲柄连杆机构动力学模型,分析了其工况载荷,并在缸体、缸盖和缸垫有限元模型的基础上,确定出工况载荷下发动机密封性能对结合面压力分布的要求,最后利用螺栓组连接与结合面压力间的关联模型反求出各螺栓预紧力的大小,通过与该型发动机已有装配连接工艺对比,验证了该设计方法的可行性.

Assembly Connection Design Orienting to Sealing Performance of Joint Surface

For designing assembly connection process to meet the requirements of sealing performance of joint surface,a digital assembly process design method oriented to sealing performance of joint surface is proposed.The effects of preload sequence and magnitude on the connection performance are investigated with nonlinear contact finite element and elastic interaction theory.Then the correlation between assembly processes and connection performances is constructed.The desirable assembly process is evaluated inversely by the correlation models according to the requirements of sealing performance under working conditions.The assembly process design of motor cylinder block and cover is taken as an example to verify the feasibility of the proposed method.Dynamic model of crank rod is established to analyze working loadings of motor.Then the joint requirements for sealing performance are determined by the finite element models of cylinder block and cover.Thus the assembly preloads can be obtained with correlation models of assembly processes and joint performances.Comparison with the existing results indicates that the proposed method is feasible.