small internal gear

例句：

1. 1. The small internal gear is essentialfor the smooth operation of the machine.
   小型内部齿轮对于机器的平稳运行至关重要。
2. 2. Theengineer designed a new small internal gear toimprove efficiency.
   工程师设计了一种新型小型内部齿轮以提高效率。
3. 3. The small internal gear was usedin the transmission system of the car.
   小型内部齿轮被用于汽车的传动系统。