Interlocking Stator Back-Iron and Heat Sink for Better Heat Transfer
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Solution Overview
Problem
The integration of electric motors and their control systems within vehicle wheels poses increased thermal management challenges, leading to reduced efficiency and power generation capabilities.
Innovation Solution
A stator design that enhances the retention of the stator back-iron to a heat sink, increasing the surface area of their interface for improved thermal conductivity and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the stator back-iron is retained to the heat sink using conventional methods, then the manufacturing process is simple, but the thermal conductivity and heat transfer efficiency are insufficient
Solution Approach 1:
The stator back-iron is divided into multiple segments with protrusions that interface with corresponding recesses in the heat sink. This segmentation allows for improved thermal contact while maintaining manufacturing feasibility through modular assembly.
Solution Approach 2:
The retention mechanism extends from a simple planar interface to a three-dimensional interlocking structure with protrusions and recesses. This dimensional change increases the contact surface area and improves thermal conductivity without significantly complicating the manufacturing process.
2Temperature
If the interface surface area between stator back-iron and heat sink is increased, then thermal conductivity improves, but the manufacturing precision requirements increase
Solution Approach 1:
By segmenting the back-iron into multiple pieces with protrusions, the total interface surface area is increased while each individual protrusion can be manufactured with standard precision tolerances, avoiding the need for ultra-precise monolithic manufacturing.
Solution Approach 2:
The protrusions act as intermediary elements that bridge the gap between the back-iron and heat sink, providing mechanical interlocking and thermal conduction pathways without requiring extremely tight tolerances across the entire interface.
3Productivity
If conventional cooling methods are used in integrated in-wheel motors, then the device complexity is low, but thermal management effectiveness is insufficient leading to reduced efficiency
Solution Approach 1:
The cooling function is merged with the structural back-iron component by integrating protrusions directly into the back-iron segments. This combines thermal management with structural support, improving efficiency without adding separate cooling system complexity.
Solution Approach 2:
The back-iron segments with protrusions provide their own thermal management function by directly contacting the heat sink. The structure serves dual purposes of mechanical support and thermal conduction, eliminating the need for additional dedicated cooling components.
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 design improves the structural integrity of the electric motor and enhances thermal management by increasing heat transfer from the stator back-iron to the heat sink, thus maintaining efficiency and power generation.
Implementation Method 1
increasing the surface area of the interface between the stator back-iron and the heat sink to allow the thermal interface between these two components to be improved, thereby improving heat transfer from the stator back-iron to the heat sink
Data Source
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AI summary
A stator for an electric motor, the stator comprising a back-iron having a first surface and a heat sink having a second surface, wherein the first surface of the back-iron includes a plurality of keying features arranged to retain the heat sink to the back-iron, wherein the heat sink is arranged to provide cooling to the back-iron via the second surface, and wherein the second surface has complementary keying features to the plurality of keying features on the first surface that are formed by casting the heat sink on the first surface of the back-iron.