C620普通车床第二轴上有三只齿轮,除一只双联齿轮在轴上滑动外,另外两只齿轮依靠挡圈固定在花键轴上(图1)。在使用中,由于变速时车头未停稳或齿轮互相错牙,很容易造成挡圈撞断和跳槽、失去定位作用,使齿轮轧毛碎裂、严重的还会引起花键轴扭曲。为此,我们对原结构进行了改进(图2、3)。将花键轴上挡圈槽加深加宽,齿轮3上加工出一凹台阶孔,中间放哈夫垫圈。这样增加了定位刚性,克服了上述缺点,而且装拆也很方便。此方法,后又推广到C630 There are three gears on the second axis of C620 common lathe. All but one double gear slides on the shaft, and the other two gears are fixed on the spline shaft by the retaining ring (Figure 1). In use, because the front of the gearshift is not stable or the gears are misaligned with each other, it is easy to cause the rings to break off and jump, losing the positioning effect, causing the gears to crack, and causing serious spline shaft distortion. To this end, we have improved the original structure (Figure 2,3). The spline shaft to deepen the retaining ring groove widening gear 3 machined a concave step hole, the middle of the Hoff washer. This increased positioning rigidity, to overcome the above shortcomings, but also easy to assemble and disassemble. This method, then extended to the C630