roll groove

例句：

1. 1. The machine has a roll groove that allows it to turn easily.
   这台机器有一个滚筒槽，可以轻松转动。
2. 2.The car's wheels have a roll groove to improve traction.
   汽车的车轮有滚筒槽，以改善抓地力。
3. 3.The engineer designed the roller groove to reduce friction between the gears.
   工程师设计了滚筒槽，以减少齿轮之间的摩擦。