我们曾设计制造一种简易活顶尖（详见“机械制造”1997年第8期），经过一段时间的使用，发现其结构只要再进行少许改进，便可更完善。改进后的简易活顶尖有两种，即I型和II型。（1）I型如图1所示。由于顶尖轴颈和顶尖雄套前端有多个滚珠支承并主要承受轴向力，使滚珠受力大大减 We have designed and manufactured a simple living top (see Mechanical Manufacturing, No. 8, 1997). After a period of use, we found that the structure can be more improved with a few minor improvements. There are two types of improved live tips: Type I and Type II. (1) I type shown in Figure 1. Due to the top journals and the top of the male sleeve with multiple ball bearings and bearing the axial force, the ball is greatly reduced in force