The electric motor axle is the assembly located at the end of the transmission system in a steer-by-wire chassis, primarily consisting of the main reducer, differential motor, half-shafts, and drive axle housing. Its function is to transmit power from the transmission, reduce speed and increase torque, change the direction of power transmission, and distribute power to the left and right drive wheels, enabling the line-controlled chassis to move. It also bears part of the chassis weight, vertical road forces, driving forces, braking forces, lateral forces, and the bending moments and torques caused by these forces.

Drivetrains can be classified into integral axles (monolithic drivetrains) and split axles (disconnected drivetrains) based on their structural form. These two types of drivetrains have significant differences in structural design, functional characteristics, and application scenarios.

An integral axle refers to a design where the main reducer, differential, half-shafts, and other components are integrated into a monolithic axle housing. The connection between the axle housing and the wheels is rigid, with the entire axle housing serving as a single unit to bear the vehicle's weight.

A split axle refers to a design where the left and right wheels are connected to the vehicle body via independent suspension systems, with the half-shafts and differential housed in separate compartments. The axle housing is no longer an integrated unit but is instead split into separate sections.

The electric motor axle works in close coordination with the robot's suspension system to effectively filter out road vibrations, thereby enhancing the driving stability of the autonomous robot's chassis. Drivetrains with an integrated axle structure are typically paired with an integrated suspension system, offering high strength and stiffness, making them suitable for carrying heavy loads and handling harsh road conditions; Drivetrains with a split axle structure are often paired with an independent suspension system, enabling better adaptation to complex road conditions and providing superior handling performance.

Drive shafts offer multiple key advantages in a variety of applications. Their modular design simplifies integration with various vehicles, while their efficiency ensures minimal power loss during energy transmission. In electric mobility vehicles, compact drive shafts enhance maneuverability in confined spaces, such as homes or crowded areas. For off-road vehicles, the robust axle is equipped with reinforced gears and impact-resistant performance, providing reliable performance on rugged terrain. Additionally, advancements in materials and engineering have reduced noise and vibration, enhancing user comfort.

The electric motor axle is a core component of a vehicle's power transmission system, and its structure varies depending on the application and drive type, but typically includes the following key components:

1. Differential

The differential is a crucial component of the drive axle, enabling the left and right drive wheels to rotate at different speeds when turning or driving on uneven surfaces. This functionality ensures pure rolling between the wheels and the ground, preventing abnormal tire wear and power loss, while significantly improving vehicle stability and maneuverability. When the vehicle turns, the differential automatically adjusts the rotational speeds of the left and right wheels based on factors such as the radius of the curve and vehicle speed, enabling the vehicle to smoothly navigate the curve while reducing the risk of body roll and loss of control.

2. Reducer

Its primary function is to reduce rotational speed and increase torque to meet the requirements of line-controlled chassis operation. Additionally, it can alter the direction of power transmission, converting the longitudinal direction of power output from the transmission into the lateral direction of power to the driven wheels.

3. Driveshaft and Coupling

The key components for transmitting motor power to the wheels. In a central drive system, the driveshaft may be connected to the motor and differential via a coupling (such as a universal joint).

4. Integrated Braking System

The drive axle and braking system (such as drum brakes or disc brakes) are designed as an integrated unit, with the brakes directly acting on the drive shaft or hub of the drive axle to ensure coordination between power transmission and braking.

5. Drive Axle Housing

The electric motor axle housing serves as the mounting base for components such as the main reducer, differential motor, and half-shafts. It also承受s vertical forces, driving forces, braking forces, and lateral forces transmitted from the road surface, as well as the bending moments and torques caused by these forces.

6. Suspension connection point (optional)

In vehicles that need to adapt to bumpy roads (such as off-road vehicles or logistics vehicles), the drive axle housing can be designed with suspension system connection points that absorb shocks through shock absorber springs or swing arms, improving driving stability.

Drive shafts are not only used in autonomous robot chassis, but also in a variety of vehicles, including electric four-wheelers, food trucks, flatbed trucks, small trucks, sightseeing vehicles, parade floats, golf carts, off-road vehicles, and go-karts, among others.

The electric drive axle is not exclusive to autonomous robot chassis but is used in various vehicles and applications, highlighting its versatility and importance in electric vehicle systems. These include: