Drive Module Spray Cooling via Gravity Fed Rotor Nozzles
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Solution Overview
Problem
Existing drive modules for vehicles face inefficiencies in heat rejection, with water cooling systems being expensive and requiring additional space, while air cooling systems are less effective and require ducting for adequate cooling.
Innovation Solution
A drive module with a housing, electric motor, coolant sump, inlet pipe, and transmission and differential assembly, where the electric motor has a rotor with a coolant passage and nozzle passage, and the coolant fluid is gravity-fed into the rotor to be centrifugally discharged onto the stator for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water cooling systems are used to cool the electric motor, then cooling effectiveness is improved, but system cost and space requirements increase
Solution Approach 1:
The patent merges the cooling function directly into the motor structure by integrating coolant passages within the rotor and stator components. This eliminates the need for separate external water cooling systems, thereby maintaining effective cooling while reducing system complexity and space requirements.
Solution Approach 2:
The coolant passages are nested within the motor components themselves - specifically within the rotor and stator structures. This nesting approach allows the cooling system to occupy the same space as the motor, eliminating additional external cooling components and reducing overall system complexity.
2Device complexity
If air cooling systems are used to cool the electric motor, then system cost is reduced, but cooling effectiveness and space utilization worsen
Solution Approach 1:
The patent employs a liquid coolant system (hydraulic approach) rather than air cooling. Coolant is circulated through passages within the motor components, providing superior heat transfer effectiveness compared to air cooling while maintaining a relatively simple integrated structure.
Solution Approach 2:
The cooling approach transitions from external air cooling to internal liquid cooling through three-dimensional passages integrated within the motor components. This dimensional integration improves cooling effectiveness by placing the cooling medium in direct contact with heat-generating surfaces.
3Temperature
If ducting is added to air cooling systems to direct air onto the motor, then cooling effectiveness is improved, but device complexity and space requirements increase
Solution Approach 1:
The cooling function is merged directly into the motor structure through integrated coolant passages. This eliminates the need for separate ducting systems to direct cooling media, thereby achieving effective cooling without additional space-consuming external components.
Solution Approach 2:
The coolant passages are nested within the motor components, allowing the cooling system to occupy the same spatial envelope as the motor itself. This nesting approach eliminates the need for external ducting and reduces the overall volume required for the cooling system.
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
This configuration provides an effective and space-efficient cooling system that improves heat rejection from the electric motor, enhancing the performance and compactness of the drive module.
Implementation Method 1
The coolant fluid is gravity fed into the inlet pipe
Implementation Method 2
centrifugally discharging the coolant fluid from the rotor and onto the stator to cool the motor
Implementation Method 3
coolant fluid... onto the stator to cool the motor
Data Source
AI summary
A drive module with a housing, an electric motor, a coolant sump, an inlet pipe and a transmission and differential assembly that is driven by the electric motor to drive a pair of output members. The electric motor is coupled to the housing and has a stator, which is fixedly coupled to the housing, and a rotor that is rotatable within the stator. The rotor has a coolant passage, which extends parallel to a rotational axis of the rotor, and a nozzle passage that intersects the coolant passage and extends radially outwardly therefrom. The coolant sump is configured to hold a coolant fluid. The inlet pipe is in fluid communication with the coolant sump and is received into the coolant passage. The inlet pipe is configured to feed the coolant fluid from the coolant sump into the coolant passage. The coolant fluid is gravity fed into the inlet pipe.