Hairpin Winding Insulation Ring for Vibration Crack Prevention
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Solution Overview
Problem
Existing insulation methods for hairpin windings in electrical machines are prone to cracking under vibration loads, leading to air gaps, creepage distances, and potential electrical short circuits, which compromise the performance and reliability of the electrical machine.
Innovation Solution
An annular disc-shaped insulation ring with axial openings for hairpin conductor rods, featuring spacer elements for axial positioning and retaining elements for secure placement, which provides reliable and durable insulation by preventing torque transfer and minimizing the risk of cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full potting of the stator is used to electrically insulate the hairpin winding, then insulation is achieved, but vibration loads may lead to cracks in the potting over time
Solution Approach 1:
The insulation system is segmented into discrete insulation rings positioned at specific locations along the hairpin winding, rather than using continuous full potting. This segmentation allows the insulation to accommodate vibration loads without developing cracks, as each ring can move independently with the winding structure.
Solution Approach 2:
The insulation ring acts as an intermediary component between the hairpin conductor rods and the stator structure. It provides electrical insulation while allowing relative movement, preventing direct stress transmission that would cause cracking in traditional potting materials.
2Reliability
If closed caps are used to insulate the hairpin ends, then insulation is provided, but the structure becomes more complex
Solution Approach 1:
The insulation ring serves multiple functions simultaneously: it provides electrical insulation, positions the hairpin conductor rods axially through its openings, and can accommodate vibration movement. This multi-functionality eliminates the need for separate caps and other insulating components, simplifying the overall structure.
Solution Approach 2:
The functions of insulation, positioning, and mechanical support are merged into a single insulation ring component. This consolidation replaces the need for separate caps and insulating materials, reducing structural complexity while maintaining insulation effectiveness.
3Manufacturing precision
If spacer elements are added for axial positioning, then positioning precision is improved, but manufacturing complexity increases
Solution Approach 1:
The spacer elements are integrated directly into the insulation ring as forming elements, combining the insulation function with the positioning function in a single monolithic component. This integration eliminates the need for separate positioning components while maintaining manufacturing precision.
Solution Approach 2:
The spacer elements are pre-formed as integral parts of the insulation ring during manufacturing. This preliminary formation of positioning features eliminates the need for additional assembly steps or separate positioning components, simplifying both manufacturing and assembly processes.
Data Source
AI summary
An insulation ring for a winding head of a hairpin winding of a stator of an electrical machine within a drivetrain of a motor vehicle includes an annular disc-shaped main body with a plurality of openings that extend axially through the main body and can each be penetrated at least in sections by the free ends of a pair of hairpin conductor rods. At least one spacer element protrudes out of the main body in a first axial direction and at least one retaining element protrudes out of the main body in a second axial direction.