调频调幅式轴向振动挤压花键成形过程实验研究

研究了在低频振动花键挤压成形过程中成形力的变化规律和振动加工的降载机理。利用课题组研发的调频调幅振动挤压成形机为实验设备,搭建了成形力测量系统,实测花键振动挤压时成形力的变化,并对数据进行分析。结果表明:成形力的大小主要与振动的振幅有关,尤其是回退行程,当回退行程足够大时,模具与工件间的摩擦力将工件拉伸至屈服段,立即反向挤压,由于包辛格效应(Bauschinger),成形力显著降低;另外,良好的润滑条件可以有效降低成形力,模具回退瞬时离开材料变形区时,润滑液进入,降低了材料与模具间的摩擦,从而降低成形力。实验研究表明,对于模数为0.47、齿数为36的小模数渐开线外花键挤压成形,采用频率10 Hz、前进行程1.38 mm、回退行程0.67 mm时,成形力降低了27%,降载效果显著。

Experimental investigation on the extrusion process of axial vibration with frequency and amplitude modulated for spline

The change rule of forming force and the load-restraining mechanism of vibration machining during the extrusion process of spline under low frequency vibration were studied.The measuring system of forming force was set up by the frequency modulation and vibration modulation extrusion machine developed by our research group.Therefore, the change of forming force was measured, and the measuring data were analyzed.The results show that the forming force is mainly related to the vibration amplitude, especially the retraction stroke.When the retraction stroke is large enough, the friction between mold and workpiece can make the workpiece yield by stretching, and the reverse extrusion is carried out immediately.However, the forming force is significantly reduced due to Bauschinger effect.In addition, the good lubrication conditions can effectively reduce the forming force due to the lubricant result in reducing the friction between material and mold when the mold backs off instantly away from the material deformation zone.The experimental results show that the forming force is reduced by 27% under the frequency of 10 Hz, the forward stroke of 1.38 mm and the retraction stroke of 0.67 mm for the extrusion of small modulus involute spline with the modulus of 0.47 and the teeth number of 36.Thus, the load-restraining effect is significant.