Three-Motor Electric Drive Axle for Cost-Effective Torque Vectoring
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Solution Overview
Problem
Developing bespoke electric motors for high-performance electrified vehicles is cost and time prohibitive, and existing two-motor setups are high-cost solutions.
Innovation Solution
A three-motor electric drive axle configuration with two geartrains, utilizing off-the-shelf electric motors and gearsets, provides forward and reverse propulsion, dynamic torque vectoring, and tank-turn/tank-steer capabilities, achieving high performance at lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If bespoke electric motors are developed for high-performance electrified vehicles, then high output performance is achieved, but development cost and time increase significantly
Solution Approach 1:
The powertrain is segmented into three separate electric motors (first, second, and third motors) that can be independently controlled. This segmentation allows the use of off-the-shelf motors with lower individual outputs while collectively achieving high-performance propulsion, avoiding the need for a single high-output bespoke motor
Solution Approach 2:
Multiple electric motors are merged into a single drive axle assembly with coordinated control. The first motor drives the left wheel, the second motor drives the right wheel, and the third motor provides additional torque assistance, combining their outputs to achieve high-performance capabilities without requiring individually high-output motors
2Power
If bespoke electric motors are developed for high-performance electrified vehicles, then high output performance is achieved, but development cost increases
Solution Approach 1:
The electric drive axle assembly serves multiple functions: it provides propulsion, torque vectoring, and steering capabilities using a standardized three-motor configuration. This universal design can be applied across different vehicle platforms, reducing per-unit development costs compared to custom high-output motors
Solution Approach 2:
The system uses multiple off-the-shelf electric motors that are commercially available and cost-effective, rather than investing in expensive bespoke motor development. The individual motors can be replaced or upgraded independently, reducing overall system cost
3Power
If existing two-motor setups are used, then propulsion is provided, but the solution becomes high-cost
Solution Approach 1:
The three-motor configuration allows different torque distributions to different wheels based on local conditions (traction, steering requirements, torque vectoring needs). The first and second motors provide primary propulsion while the third motor provides additional torque, creating a cost-effective high-performance solution
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The configuration achieves high-performance propulsion, efficient torque vectoring, and precise control for cornering, while reducing development costs and time-to-market.
Implementation Method 1
a first planetary gear set having a first sun gear fixed for rotation with the second output, a first carrier, and a first ring gear fixed for rotation with one of the first outputs; and a first final gear reduction having a first final drive pinion fixed for rotation with the first carrier
Data Source
AI summary
An electrified powertrain that generates and transfers drive torque to a driveline of an electrified vehicle including first and second drive wheels is provided. The electrified powertrain includes an electric drive module having a first, second and third electric motor, a first geartrain and a second geartrain. The first electric motor can have two first outputs. The second electric motor can have a second output. The third electric motor can have a third output. The first geartrain can include: a first planetary gear set having a first sun gear fixed for rotation with the second output, a first carrier, and a first ring gear fixed for rotation with one of the first outputs; and a first final gear reduction having a first final drive pinion fixed for rotation with the first carrier and a first final output that drives the first drive wheel.