concave adjustment shaft

例句：

1. 1. The machine's concaveadjustment shaft allows for easy adjustment of theangle.
   机器的凹面调整轴可以轻松调整角度。
2. 2. The engineer used a concaveadjustment shaft to adjust the gears.
   工程师使用一个凹面调整轴来调整齿轮。
3. 3.The concave adjustment shaft is essentialfor maintaining the accuracy of the machine.
   凹面调整轴对于保持机器的准确性至关重要。