shaft nut

例句：

1. 1. The engineer tightened the shaft nut to secure thebolt.
   工程师拧紧了轴心螺栓以固定螺栓。
2. 2. The machine's shaftnut was worn out after years ofuse.
   这台机器的轴心螺栓在使用多年后磨损了。
3. 3. Thetechnician replaced the shaftnut with a new one tofix the issue.
   技术人员用一个新的轴心螺栓来修复这个问题。