内螺纹低频振动冷挤压试验研究

Experimental Research on Internal Thread Formation by Cold Extrusion Based on Low Frequency Vibration

内螺纹低频振动冷挤压加工是通过挤压丝锥棱齿的振动挤压,将传统内螺纹冷挤压加工中的干摩擦状态转变为更有利的边界摩擦状态,从而改善传统内螺纹冷挤压加工过程中冷却润滑液不易进入挤压区的严重缺陷。通过试验可知:随着激振频率的不断增大,挤压扭矩呈不断增大趋势;随着激振力的不断增大,挤压扭矩呈现为先减小后增大的趋势;随着激振力臂长度的不断增大,挤压扭矩总体呈不断增大的趋势。在其他工艺参数相同条件下,低频振动冷挤压可以进一步提高传统内螺纹的牙高率和改善牙顶处凹陷的缺陷,从而提高冷挤压内螺纹的抗疲劳强度及获得更好的表面形貌。

Internal thread formation by cold extrusion based on low-frequency vibration can realize vibration extrusion by extruding tap.It can turn the process of dry friction into a more favorable state of boundary friction.Therefore it can overcome the defect of traditional cold extrusion that the coolant cannot easily enter the extrusion zone.The experimental study shows that： as the exciting frequency increases,so does the extrusion torque;as the exciting force increases,the extrusion torque decreases first,and then increases;as the exciting arm length increases,the extrusion torque also increases.Under the same conditions of the process parameters,the internal thread formation by cold extrusion based on low-frequency vibration exhibits a higher rate of thread teeth height and fewer defects of the teeth top than traditional methods,and the method can improve the fatigue strength and surface morphology of the thread so formed.