130/286kW Integrated e-axle for electric sanitation trucks/heavy-duty trucks/tractor

Single-axle adaptation models: 18-ton sanitation trucks, trucks

Twin axle adaptation models: 6 * 4 / 8 * 4 tractor

Adopt the international advanced PLM product development management system

Over the course of several months, through fully forward development

It contains 13 control review points and 96 main deliverables

With the rapid development of electric vehicle (EV) technology, the electric drive axle, as a core component for power transmission, directly impacts vehicle efficiency and performance. This paper focuses on the structural analysis of electric drive axles, exploring key components and technical features.

The core structure of an electric drive axle integrates four elements: "drive motor + transmission system + differential + half-shaft." Unlike traditional fuel vehicle axles, its drive motor typically uses a permanent magnet synchronous motor (PMSM), directly coupled with a reducer (single-stage/multi-stage) and differential, eliminating clutches and gearboxes. This simplifies the transmission chain—for example, a typical "motor-reducer-differential" integrated design shortens the axial length by 30%, reduces weight by 15%, and improves transmission efficiency to over 96%.

Lightweighting and thermal management are critical innovations. Aluminum alloy housings replace traditional cast iron, combined with liquid/air cooling channels to suppress heat from the motor and reducer. Half-shafts use high-strength steel or carbon fiber composites, reducing unsprung mass while ensuring torque transmission and enhancing vehicle handling.

（External Structure of Electric Drive Axle）

In summary, the integrated, lightweight, and high-efficiency structure of electric drive axles is a key technical driver for extending EV range and upgrading performance.

The Deep Value of Integrated Design: Modularization and Standardization Breakthroughs

The "three-in-one" (motor-reducer-differential) integration of electric drive axles is not merely a physical stacking of components but achieves synergistic optimization of function and space through modular architecture design. In traditional axles, motors, reducers, and differentials are supplied by separate vendors, requiring extensive customized development for interface matching. In contrast, electric drive axles integrate multiple components into a single functional module by unifying torque transmission axes, standardizing mounting holes, and aligning cooling interfaces. Take a mass-produced solution from a leading automaker as an example: its electric drive axle adopts an integrated die-casting process for the stator-rotor-reducer housing, reducing multi-component assembly time from 3 hours to 20 minutes while cutting the weight of connecting components by 12%. This innovation provides critical support for vehicle lightweighting and cost control.

（Internal Motor of Electric Drive Axle）

Transmission System: A Technological Leap from "Power Transfer" to "Energy Optimization"

Beyond integration, the improvement in electric drive axle transmission efficiency hinges on microstructural optimization. Take the reducer as an example: mainstream solutions use a helical gear + planetary gear set combination. Compared to spur gears, helical gears increase tooth surface contact area by 20%. Paired with micrometer-level tooth profile modification technologies (e.g., drum-shaped modification, tooth end rounding), meshing noise is reduced by 5dB, and transmission loss is cut by 3%-5%. For planetary gear sets, optimizing the matching of module and pressure angle between the sun gear and planet gears raises the load-sharing coefficient to below 1.1 (vs. ~1.3 for traditional fuel vehicle differentials), ensuring uniform stress distribution across gears and extending service life. Additionally, high-end solutions introduce an "oil-cooled motor + submerged reducer" design, where lubricating oil simultaneously handles motor winding cooling and gear lubrication. This eliminates efficiency losses from traditional split cooling systems, pushing transmission efficiency further beyond 97%.

（Internal Structure Diagram of Electric Drive Axle）

Intelligent Thermal Management: Dynamic Regulation for Full-Scenario Performance

To address thermal management needs across electric vehicle operating scenarios—rapid acceleration, constant speed, and braking—new-generation electric drive axles are equipped with intelligent temperature control systems. Core to this is the deployment of NTC temperature sensors in key heat-generating areas (motor windings, reducer bearings, differential housings), combined with real-time current data from IGBT power modules. The ECU dynamically adjusts the flow rate of the liquid cooling circuit (response time < 500ms). For instance, when motor winding temperature exceeds 120°C, the system automatically reduces coolant flow and increases fan speed to prioritize heat dissipation for high-heat components; during low-speed constant-speed driving, it minimizes pump power consumption, cutting energy use by 8%-10%. Real-world tests show that electric drive axles with intelligent thermal management maintain over 95% efficiency across ambient temperatures from -30°C to 50°C, eliminating traditional axle pain points like insufficient lubrication during cold starts and power reduction at high temperatures.  

（Internal Structure Diagram of Electric Drive Axle）

Conclusion: Deep Integration of 800V High-Voltage Platforms and X-by-Wire Chassis

With the proliferation of 800V high-voltage platforms, electric drive axles are evolving toward "high voltage and high power density." New-generation solutions, adopting silicon carbide (SiC) inverters, flat-wire motors (e.g., 8-layer/10-layer windings), and oil-cooling heat dissipation, have pushed power density beyond 5kW/kg (vs. ~3kW/kg for traditional 400V platforms). Meanwhile, integration with x-by-wire chassis is becoming increasingly prominent: the reducer output end of electric drive axles is equipped with reserved interfaces for wire-controlled differential locks, while half-shafts integrate torque sensors. This enables direct reception of commands from the chassis domain controller, facilitating more precise torque distribution and four-wheel drive coordination to support the execution layer of intelligent driving.

From "functional integration" to "intelligent collaboration," structural innovations in electric drive axles are redefining the power boundaries of electric vehicles. With advancements in material science, simulation technology, and manufacturing processes, future electric drive axles may further integrate functions such as energy storage (e.g., hub motors + distributed batteries) and sensing (built-in IMU sensors), emerging as a core node in the vehicle’s "mobile smart terminal."