粉末冶金微型螺旋齿轮成形工艺及模具结构设计

Forming Technology and Die Structure Design of Powder Metallurgy Micro Helical Gear

作为某品牌扫地机器人传动系统中的关键件,驱动电机输出轴微型螺旋齿轮过去一直采用钢材经滚齿加工完成,存在材料利用率低、能耗大和制作成本高等不足。针对上述问题,进行了铁基材料的微型螺旋齿轮粉末冶金生产工艺研究。根据烧结过程制品的膨胀或收缩导致烧结后齿轮的几何形状变化或尺寸精度降低等问题,采用变压力角方法设计齿轮成形模腔,有效控制了压后成形坯的尺寸精度,并设计了粉末冶金螺旋齿轮制品的成形模具。测试表明:改进工艺后生产的螺旋齿轮密度为6.8~7.0 g/cm^(3),硬度为50~70 HRB,耐磨性好,强度和精度均满足使用要求,且年产量达到了100万只。

As a key part of the transmission system of a brand of sweeping robot,the micro helical gear of the output shaft of the driving motor has been processed with steel by gear hobbing in the past,which has the disadvantages of low material utilization,high energy consumption and high manufacturing cost.In view of the above problems,the powder metallurgy production process of micro helical gear made of iron-based materials was carried out.According to the expansion or contraction of the products in the sintering process,the geometric shape of the gear changing or the dimensional accuracy decreasing after sintering,the variable pressure angle method was used to design the gear forming die cavity,which effectively controlled the dimensional accuracy of the formed blank after sintering.And then the forming die of powder metallurgy spiral gear products was designed.The test shows that the density of spiral gear is 6.8~7.0 g/cm^(3),the hardness is 50~70 HRB,the wear resistance is good,the strength and accuracy meet the use requirements,and the annual output of spiral gear is 1 million.