爪极精锻模具的耐久性研究

Durability research on precision forging die for claw pole

为防止爪极精锻下模凸筋处产生局部尺寸偏差而导致模具过早失效,利用有限元分析了导致爪极精锻模具使用寿命低的原因,发现磨损失效是导致爪极精锻下模凸筋处易产生尺寸偏差的主要因素。基于爪极锻造模具型腔的特点,对成形工艺进行了改善,在爪极预锻上模设置与精锻下模凸筋位置和大小相对应的凸起,可有效降低精锻下模凸筋处的温度、相对滑动速度和接触应力,使单个锻次的磨损量由优化前的1.08×10^(-5) mm减小为3.65×10^(-6) mm,且优化后的锻件未出现折叠、湍流和涡流等缺陷。根据该优化方案加工出模具并进行实际生产验证,结果显示,该优化方案使爪极精锻下模的平均使用寿命由优化前的5000件提高至6000件。

In order to prevent the premature failure of die caused by the local dimensional deviation at the convex rib of lower die for claw pole precision forging,the reasons for the low service life of precision forging die for claw pole were analyzed by the finite element method,and it was found that the wear failure was the main factor causing the dimensional deviation at the convex rib of lower die for claw pole precision forging.Then,based on the characteristics of forging die cavity for claw pole,the forming process was improved,and the protrusion corresponding to the position and size of convex rib in the precision forging lower die was set in the pre-forging upper die for claw pole,which could effectively reduce the temperature,relative sliding speed and contact stress at the convex rib of precision forging lower die,and make the wear amount of a single forging pass from 1.08×10^(-5) mm before optimization reduce to 3.65×10^(-6) mm.Furthermore,the improved forgings had no defects such as folds,turbulence and eddy currents,and according to the optimized scheme,the die produced under the optimized scheme was verified in actual production.The results show that the optimized scheme increases the average service life of the precision forging lower die for claw pole from 5000 pieces before optimization to 6000 pieces.