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针对大模数圆柱直齿轮冷挤压过程中均匀过盈量组合凹模易出现开裂的问题,提出一种变过盈量组合凹模的设计方法,并以直径比、中圈内壁锥角和过盈系数为设计变量,以降低模芯内壁等效应力、避免模芯出现周向拉应力和避免内外圈塑性变形为优化目标,建立变过盈量组合凹模结构参数与综合加权评分值的Kriging模型。应用Kriging模型结合粒子群算法,在可行变量空间内寻优,得到最优工艺参数组合为:n_2=1.55,n_3=2.55,γ’=1.25°,β_2=2.5‰,β_3=2.4‰。研究结果表明,采用优化后的变过盈量组合凹模可有效避免组合凹模的破裂,提高模具的使用寿命。
In order to solve the problem that cracking of composite die with uniform interference is difficult during the cold extrusion of large modulus cylindrical spur gear, a design method of composite die with variable interference margin is proposed. The diameter ratio, The interference coefficient is the design variable to reduce the equivalent stress on the inner wall of the mold core and avoid the circumferential tensile stress in the mold core and avoid the plastic deformation of the inner and outer rings as the optimization objective and establish the composite structural parameters of the interference surplus and the comprehensive weighted scoring value Kriging model. The Kriging model and the particle swarm optimization algorithm are used to find out the optimal process parameters in the feasible variables space. The optimum process parameters are obtained as follows: n 2 = 1.55, n 3 = 2.55, γ ’= 1.25 °, β 2 = 2.5 ‰ and β 3 = 2.4 ‰. The research results show that the optimized composite model with variable interference can effectively avoid the crack of the composite die and improve the service life of the die.