Four-Mode Dual-Motor Drive Axle for Torque Coupling and Vectoring
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Solution Overview
Problem
Current electric vehicle drive systems, particularly in China, lack integration of independent torque control for wheels, which is essential for torque vectoring, leading to inefficiencies in power distribution and handling stability, especially in high-performance electric vehicles.
Innovation Solution
A four-mode dual-motor coupling electric drive axle that integrates torque vectoring (TV) function, allowing switching between single-motor drive, TV drive, dual-motor torque coupling, and dual-motor speed coupling modes through control of three clutches and the power coupling differential, enabling efficient power distribution and improved handling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a TV motor is introduced to the centralized drive axle to realize torque vectoring distribution, then precise torque distribution control is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent combines the TV function with the existing dual-motor coupling system by integrating the auxiliary drive motor's torque output through a TV coupler (planetary gear mechanism) to the power output mechanism. This merging approach enables torque vectoring distribution without requiring a completely separate TV motor system, thus improving torque distribution control while limiting the increase in device complexity.
Solution Approach 2:
The auxiliary drive motor serves multiple functions: it can operate independently for torque vectoring distribution, assist the primary drive motor for torque coupling, or regulate speed for the primary motor. The TV coupler and power coupling differential also serve multiple functions across different operating modes. This multi-functionality reduces the need for dedicated components, thereby improving control capability while constraining complexity increase.
2Power
If dual-motor coupling system is implemented, then power performance and driving economy are improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic mode switching between single-motor drive, TV drive, dual-motor torque coupling, and dual-motor speed coupling modes through three controllable clutches. This dynamic reconfiguration allows the system to adapt to different driving conditions, achieving superior power performance and driving economy while managing complexity through intelligent control rather than permanent structural additions.
Solution Approach 2:
The drive axle is segmented into functionally independent modules: primary drive motor, auxiliary drive motor, reducer, TV coupler, power coupling differential, and clutch mechanisms. This modular segmentation allows each component to be optimized for its specific function while enabling flexible combinations for different operating modes, thereby achieving enhanced power performance with controlled complexity through standardized interfaces.
3Stability of the object's composition
If hub-motor independent drive system is used for torque vectoring, then handling stability and maneuverability are improved, but unsprung mass increases
Solution Approach 1:
Instead of using heavy hub motors at each wheel, the patent introduces a centralized TV coupler (planetary gear mechanism) as an intermediary device that distributes torque between left and right wheels. This intermediary approach achieves the same torque vectoring effect for improved handling stability and maneuverability without the penalty of increased unsprung mass associated with distributed hub motors.
Data Source
AI summary
A four-mode dual-motor coupled electric drive axle, including a primary drive motor, an auxiliary drive motor, a reducer, a torque vectoring (TV) coupler, a power coupling differential, a housing, and a power output mechanism. The TV coupler is switchable among disconnected mode, TV mode, and reducer mode by controlling a first clutch and a second clutch. The power coupling differential is switchable between torque coupling mode and speed coupling mode by controlling a third clutch. The electric drive axle is switchable among single-motor drive mode, TV drive mode, dual-motor torque coupling drive mode, and dual-motor speed coupling drive mode by controlling the TV coupler and the power coupling differential.