sprocket silentchain

例句：

1. 1.The sprocket on the bicycle is worn out.
   自行车上的链轮磨损了。
2. 2. The car's engine sprocket has seized up.
   汽车发动机的链轮卡住了。
3. 3.The train's sprocket system was designed to be easy to replace.
   火车的链环系统设计成容易更换。