The key role of automotive gear mainly includes the following aspects:

1. Power transmission: The car gear is the core component of power transmission, which transmits the power of the engine from the drive gear to the driven gear, thereby driving the wheel.

2. Speed control: The car gear can change the rotation speed of the engine, thereby controlling the speed. By changing different transmission ratios, the gear can adapt to different driving needs and road conditions.

3. Steering control: The differential gear and steering gear work together to enable the car to steer flexibly and achieve precise control.

4. Accurate matching: the car gear needs accurate matching and transmission system interconnection to ensure the accurate transmission of power and torque, and there will be no stuck or slipping.

5. Durability and stability: automotive gears need to withstand complex conditions such as high speed, high torque and frequent shifting, so they need to have high wear resistance, fatigue resistance and stability to ensure long-term reliability and durability.

In summary, automotive gears are a key component of the internal power transmission and speed control of the car, and they are connected to each other through precise fit and transmission systems to ensure that the car can move smoothly and perform the required operations.