Modular Gearbox Attachment for EV Thermal Management
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Solution Overview
Problem
Electric vehicle motors with high torque output capabilities face thermal overload issues due to the thermal limitations of the motor's stator and inverter's insulated-gate bipolar transistors (IGBTs), particularly in off-roading, rock crawling, heavy-duty towing, and extreme weather conditions.
Innovation Solution
A modular high-low range gearbox attachment is integrated into individual wheel drive units of a four-motor powertrain assembly, providing a high ratio gear reduction that shifts the strain of high torque operations from the motor to the wheel, thereby alleviating thermal limitations. This gearbox attachment includes a housing, gear reduction assembly, and actuator assembly, and is easily attachable to existing wheel drive units without replacing the A-shield or half shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the motor operates at high torque output, then the torque capability is improved, but thermal overload occurs due to thermal limitations of the motor's stator and inverter's IGBTs
Solution Approach 1:
A gearbox attachment with planetary gear reduction assembly is introduced as an intermediary mechanical device between the motor and wheel. This gearbox provides gear reduction (e.g., 4:1 ratio) that multiplies torque while reducing the speed and thermal load on the motor, allowing the motor to operate in a more thermally manageable range while still delivering high torque to the wheel.
Solution Approach 2:
The system changes the operating parameters by introducing variable gear reduction ratios. The gearbox attachment can provide different reduction ratios (e.g., 1:1, 2:1, 3:1, 4:1) depending on the operating condition, allowing the motor to operate at lower torque levels during normal conditions and redirecting thermal management resources when high torque is required.
2Ease of manufacture
If a fixed gear ratio is used in the gearbox attachment, then the manufacturing cost is reduced, but the adaptability to different driving conditions deteriorates
Solution Approach 1:
The gearbox attachment employs a selectable or variable gear ratio mechanism that allows the system to dynamically adjust the reduction ratio based on driving conditions. An actuator assembly can shift between different gear ratios (e.g., low range, high range, neutral) to optimize performance for different scenarios such as off-roading, rock crawling, heavy duty towing, or normal driving.
Solution Approach 2:
The gearbox attachment is designed as a multi-functional device that can serve multiple purposes: providing high torque multiplication for off-road conditions, offering direct drive for normal conditions, and enabling various gear ratios for different operating scenarios. This universal design allows a single attachment to replace multiple specialized components.
3Ease of operation
If the gearbox attachment is made modular and easily attachable, then the ease of installation is improved, but the structural complexity increases
Solution Approach 1:
The gearbox attachment is designed as a modular, self-contained unit that can be independently installed on existing wheel drive units. The attachment includes separate components (housing, gear reduction assembly, actuator assembly) that can be pre-assembled and tested before installation, simplifying the overall installation process while managing structural complexity within the modular unit itself.
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 gearbox attachment enables high torque at low speeds for extended durations, effectively managing thermal limitations and enhancing performance in demanding conditions like off-roading and extreme weather, while maintaining modularity for easy integration and aftermarket modifications.
Implementation Method 1
The gear reduction assembly is adapted to provide a gear reduction for a higher torque and slower speed in a gear reduction mode than a torque and speed in a standard mode
Data Source
AI summary
A gearbox attachment of a wheel drive unit A-shield assembly for an electric vehicle four motor powertrain system is disclosed. The gearbox attachment includes a housing, a gear reduction assembly, and an actuator assembly. The housing is adapted to fasten to an A-shield of the wheel drive unit A-shield assembly. The housing includes an outer ring. The gear reduction assembly is at least partially received in the outer ring. The gear reduction assembly is adapted to receive an output of a gearbox of the wheel drive unit A-shield assembly that is adapted to provide an output of a motor to a single wheel of the electric vehicle. The gear reduction assembly is adapted to provide a gear reduction for a higher torque and slower speed in a gear reduction mode. The actuator assembly adapted to actuate the gear reduction assembly output between the gear reduction mode and a standard mode.