我厂在生产上海50型拖拉机后轿半轴齿时(图1),由于零件内花键较长、壁薄(最薄处仅5mm),在拉削内花键及热处理时,均会产生不同程度的变形,而热处理变形尤为严重。一般说,大端M值基本不变(或稍有胀大),小端M值缩小得较多。所以,整个花键孔的M值呈现出从大端向小端逐渐缩小的锥形。 M值即跨棒距,它是用两根直径相同的标准圆棒放在齿轮直径方向上的两齿间,用量具测出两圆棒间的距离(见图2及附表)。为此,我们曾采取一些补救措施,但始终不能使M值保持稳定,总有小部分零件报废。为了解决上述问题,我们采用了内花键冷扩挤的方法。在热处理前,有意将小头的M值挤得比图纸上 I plant in the production of Shanghai 50 tractor sedan half shaft teeth (Figure 1), due to the spline longer parts, thin wall (thinnest at only 5mm), in the broaching of the internal spline and heat treatment, will have Different degrees of deformation, and heat treatment deformation is particularly serious. In general, the big end M value is basically unchanged (or slightly swollen), small end M value is reduced more. Therefore, the M value of the entire spline hole shows a taper that gradually decreases from the large end to the small end. M value that is across the stick, it is the use of two standard diameter rods on the gear diameter of the gear between the two teeth, measured by the distance between the two round rod (see Figure 2 and Schedule). To this end, we have taken some remedial measures, but always can not keep the value of M stable, there are always a small part of the scrapped. In order to solve the above problems, we have adopted a method of expanding the inner spline cold extrusion. Before heat treatment, intend to squeeze the head of the M value than the drawings