Electric Motor Coupling Assembly for Proactive Wheel Slip Prevention
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Solution Overview
Problem
Traditional axle locker mechanisms cannot be incorporated on vehicles with electric motors on each drive wheel, and existing electronic solutions for wheel slip are largely reactive and do not prevent wheel slip effectively.
Innovation Solution
A coupling assembly that mechanically couples drive shafts of multiple electric motors for concurrent rotation, controlled by a controller that determines the suitability of locking or unlocking based on vehicle conditions, including wheel speeds and driver input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional axle locker mechanisms are used, then wheel slip can be prevented effectively, but they cannot be incorporated on vehicles having electric motors on each drive wheel
Solution Approach 1:
The coupling assembly is segmented into separate components including a first stub shaft connected to the first electric motor, a second stub shaft connected to the second electric motor, and a collar that can engage with either stub shaft. This segmentation allows the mechanism to be adapted to electric motor configurations while maintaining the axle locking function.
Solution Approach 2:
Instead of using a traditional axle locker that locks the differential mechanism, this invention inverts the approach by mechanically coupling the output shafts of multiple electric motors together. The collar engages with stub shafts to directly couple the motors, preventing relative motion between them and achieving the axle locking effect through a fundamentally different mechanism.
2Reliability
If electronic devices are used to detect and adjust power routing, then wheel slip can be addressed, but the response is reactive rather than proactive
Solution Approach 1:
The mechanical coupling assembly proactively prevents wheel slip by physically coupling the motors together before slip occurs. The collar can engage with the stub shafts to mechanically ensure concurrent rotation, eliminating the need for reactive electronic intervention and reducing the response time to zero since the prevention is built into the mechanical structure.
3Reliability
If a coupling assembly mechanically couples drive shafts for concurrent rotation, then traction is enhanced proactively, but the device complexity increases
Solution Approach 1:
The coupling assembly is divided into discrete, simple components: stub shafts that connect to motor outputs and a collar that engages with these stub shafts. This segmentation allows each component to be simple in design while the assembly provides the complex function of mechanical coupling, making the system easier to manufacture and maintain despite its functional complexity.
Data Source
AI summary
An electrified powertrain for a vehicle includes first and second electric motors, first and second gearbox assemblies, a coupling assembly and a controller. The first electric motor includes a first stator, a first rotor and a first output shaft. The second electric motor includes a second stator, a second rotor and a second output shaft. The first gearbox assembly operably connects the first output shaft with a first drive axle that drives a first drive wheel. The second gearbox assembly operably connects the second output shaft with a second drive axle that drives a second drive wheel. The coupling assembly has a first stub shaft, a second stub shaft, a collar and an actuator. The coupling assembly is movable between an unlocked position wherein the first and second stub shafts are disconnected and a locked position wherein the first and second stub shafts are fixed for concurrent rotation.