oval gear

例句：

1. 1. The car has a new set of oval gears installed.
   这辆车安装了一套新的椭圆齿轮。
2. 2.The engineer used the oval gear to make the machine run smoothly.
   工程师使用椭圆齿轮使机器运行顺畅。
3. 3. The oval gear is essential for the transmission system in the car.
   椭圆齿轮对于汽车的传动系统至关重要。