套管零件 (见图 1)是菲亚特转向机上转向立柱合件的重要零件 ,其花键质量 ,尤其是花键中心线与孔中心线之同轴度 ,直接关系到转向机的偏摆 ,影响转向机质量 ,曾是质量攻关项目之一。　　一、原加工工艺及拉床夹具原套管加工工艺为缩孔→切断、扩孔→平端面、倒角、镗孔→拉花键 Sleeve parts (see Figure 1) is the Fiat steering steering column parts of the important parts, the spline quality, especially the spline centerline and bore centerline coaxiality, is directly related to the deflection of the steering machine, the impact Steering machine quality, was one of the quality research projects. First, the original processing technology and broaching machine tool for the original casing shrinkage shrinkage → cut off, reaming → flat face, chamfering, boring → pull the spline