shaft allowance

例句：

1. 1. The machine requires a certain amount of shaft allowance to operate smoothly.
   这台机器需要一定的轴心余量才能顺畅运行。
2. 2. The engineer added an extra clearance allowance to the design to prevent any potential problems.
   工程师在设计中增加了额外的轴心余量，以防止任何潜在的问题。
3. 3. The car's engine has a clearance allowance that allows it to fit into tight spaces.
   这辆车的发动机有轴心余量，可以适应狭窄的空间。