An automotive rear axle plays a crucial role in the vehicle transmission and suspension systems. It mainly serves the following purposes:

1. Power transmission: The rear axle transmits the power generated by the engine to the rear wheels via the transmission shaft to drive the car. Rear axle components, including differential and driver shaft, enable power transmission and allow the car to move forward or backward.

2. Supporting vehicle weight: The rear axle bears the rear part of the car, including passengers, cargoes, and other loads. By playing a supporting role, it ensures stability of the rear part of the car and normal operation of the suspension system.

3. Suspension system: The rear axle is also an important part of the vehicle suspension system. By connecting to the rear wheels and suspension system, it can alleviate vibration and impact resulting from uneven road surfaces, and improve ride comfort and driving stability.

4. Steering function: In some vehicle models, the rear axle may also provide steering function: Its differential and driver shaft are designed to assist with turning or backing of the car.

In sum, automotive rear axle plays a crucial role in the transmission and suspension systems of vehicles, and is of great importance for driving performance, stability, and maneuverability of vehicles.

Differences between front axle and rear axle in a car:

1. Position:

Front axle: The front axle is often located at the front part of a vehicle and near the front wheels. In a front-engine vehicle, the front axle is connected to the front wheels for transmitting power and supporting the front part of the vehicle.

Rear axle: The rear axle is often located at the rear part of a vehicle and near the rear wheels. In a rear-engine vehicle, the rear axle is connected to the rears wheels for transmitting power and supporting the rear part of the vehicle.

2. Function:

Front axle: The front axle of a car is mainly responsible for transmitting power, supporting the front part of the vehicle, and assisting with steering. It transmits power generated by the engine to the front wheels via the transmission system while supporting the front part of the vehicle.

Rear axle: The rear axle of a car is mainly responsible for transmitting power, supporting the rear part of the vehicle, and providing suspension. It transmits power to the rear wheels via the transmission system, supports the rear part of the vehicle, and reduces vibration on uneven roads.

3. Structure:

Front axle: The structure of a front axle is typically simple, including differential, driver shaft, wheel hub, and other components. A front axle is designed in such a way to meet steering and transmission needs.

Rear axle: The structure of a rear axle is more complicated, including differential, driver shaft, braking system, and other components. The design of a rear axle takes into account multiple functions such as transmission, supporting, and suspension.

In summary, there are certain differences between front and rear axles of a car in terms of position, function, and structure. They provide transmission, supporting, and suspension functions for the front and rear parts of the vehicle respectively. Together they form the transmission and suspension systems of the vehicle, guaranteeing its normal operation and driving performance.