Overmoulded Brushless Motor Stator for Airflow Cooling
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Solution Overview
Problem
Brushless motors face challenges in size, weight, power density, manufacturing cost, efficiency, reliability, and noise, with existing methods of adhering stator core sub-assemblies to the frame leading to thermal issues and reduced airflow, which affects cooling and increases emissions.
Innovation Solution
The solution involves overmoulding a frame to a stator assembly with exposed stator core arms, incorporating turbulators and struts for enhanced thermal transfer and airflow, which reduces the need for individual adherence and increases stiffness while providing a sealed bearing cartridge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stator core sub-assemblies are individually adhered to the frame, then manufacturing process is simpler, but thermal transfer from stator cores is reduced and airflow is blocked
Solution Approach 1:
The frame and stator core sub-assemblies are merged into a single integrated structure through overmoulding, eliminating the need for separate adherence steps while improving thermal transfer and airflow pathways
2Ease of manufacture
If stator core sub-assemblies are individually adhered to the frame, then assembly is easier, but frame stiffness is reduced
Solution Approach 1:
The overmoulding process merges the frame and stator core sub-assemblies into a single integrated structure, eliminating assembly steps while significantly improving frame stiffness and structural integrity
3Temperature
If frame is overmoulded to stator assembly with exposed stator cores, then thermal management is improved, but manufacturing complexity increases
Solution Approach 1:
The overmoulding process combines frame formation and stator core integration into a single manufacturing step, improving thermal management while actually reducing overall manufacturing complexity by eliminating separate adherence operations
Solution Approach 2:
The frame design incorporates localized features such as turbulators and struts at specific positions to optimize airflow and thermal transfer, allowing complex thermal management functions to be integrated into the moulding process itself
4Strength
If stator cores are fully enclosed in frame, then structural integrity is improved, but cooling airflow is blocked
Solution Approach 1:
The frame design incorporates localized open regions and airflow pathways at specific positions around the stator cores, allowing structural integrity to be maintained in enclosed areas while permitting cooling airflow through designated channels
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 approach results in improved thermal management, reduced emissions, and increased power density by allowing airflow through the stator cores, enhancing cooling and maintaining structural integrity.
Implementation Method 1
Overmoulding the frame to the stator assembly may, in some examples, provide increased thermal transfer from the stator core sub-assemblies to the frame compared to embodiments where stator core sub-assemblies are adhered to the frame
Implementation Method 2
By overmoulding the frame to the stator assembly such that at least a portion of the back and the first and second arms of each stator core is exposed through the frame, at least a portion of each stator core may be exposed to airflow through the brushless motor in use, which may provide a cooling effect
Data Source
AI summary
A brushless motor has a stator assembly, and a frame within which the stator assembly is housed. The stator assembly has a plurality of stator core sub-assemblies each including a stator core, a bobbin attached to the stator core, and a winding wound about the bobbin. Each stator core has a back and first and second arms extending from the back. The frame is overmoulded to the stator assembly such that at least a portion of the back and the first and second arms of each stator core is exposed through the frame.