Coaxial E-Axle Rotor Shaft Locking Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In dual-motor coaxial electric axle assemblies, if one motor loses the ability to power its respective wheel, the vehicle may drive poorly due to uneven torque distribution, potentially leading to unsafe driving conditions.
Innovation Solution
A locking assembly is introduced that allows the still-functional motor to mechanically couple with the other motor, enabling it to power both axle shafts, allowing the vehicle to 'limp home' safely until repairs can be made.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one motor fails in a dual-motor coaxial e-axle assembly, then the vehicle can still operate with one motor powering one wheel, but the torque distribution becomes uneven leading to poor driving performance and unsafe conditions
Solution Approach 1:
The locking assembly merges the two independently powered axle shafts into a unified power transmission system. When one motor fails, the locking mechanism engages to couple the functional motor's rotor shaft to the non-functional motor's rotor shaft, allowing a single motor to power both wheels through the differential, thereby restoring safe torque distribution
Solution Approach 2:
The system dynamically transitions between two operational modes: normal dual-motor independent operation and single-motor coupled operation. The locking assembly enables this dynamic reconfiguration based on motor functionality, allowing the system to adapt to failure conditions while maintaining safe operation
2Reliability
If a locking assembly is added to enable one motor to power both wheels, then driving safety is improved, but the device complexity increases
Solution Approach 1:
The locking assembly utilizes existing components (rotor shafts, differential) for multiple functions: during normal operation, the rotor shafts independently transmit power to respective wheels; during failure mode, the same rotor shafts are coupled by the locking mechanism to enable single-motor power transmission to both wheels, eliminating the need for additional dedicated components
3Ease of operation
If the locking assembly couples the rotor shafts, then torque distribution to both wheels is restored, but the mechanism requires additional components
Solution Approach 1:
The locking assembly acts as an intermediary mechanism between the two rotor shafts. It includes a locking member that can engage with features on both rotor shafts, providing a mechanical coupling path that allows torque from one motor to be transmitted through the differential to both wheels when needed
Data Source
AI summary
A system for selectively locking two coaxial axle shafts of an electric axle is provided. The system includes a first electric motor having a first rotor shaft configured to drive a first axle shaft. The system also includes a second electric motor having a second rotor shaft configured to drive a second axle shaft coaxial with the first axle shaft. An actuator is configured to selectively activate to operate in a safety mode. When operated to assume the safety mode, the actuator causes the first rotor shaft to lock to the second rotor shaft, such that the two shafts rotate in unison. This allows one of the two motors to drive both axle shafts in the event of a fault in one of the motors.