Stator core insulating member with non-contact portions
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Solution Overview
Problem
Conventional stator cores in electric motors experience thermal stress and potential breakage due to mismatched linear expansion coefficients between the core body and insulating members, leading to reduced performance and reliability, especially in temperature-varying environments like compressors.
Innovation Solution
A stator core design featuring an insulating member with distinct contact and non-contact portions, integrated with the core body, where the insulating member has a different linear expansion coefficient, and is strategically positioned at the peripheral walls to reduce thermal stress and prevent breakage, using resin materials like polybutylene terephthalate with glass fibers for enhanced strength and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating member is made of resin material to provide insulation, then insulation performance is improved, but thermal expansion mismatch causes stress and potential breakage
Solution Approach 1:
The insulating member is divided into multiple independent resin blocks positioned at different locations (inner peripheral wall, outer peripheral wall, and tooth portions). Each block independently provides insulation without being constrained by thermal expansion of adjacent blocks, reducing stress concentration and preventing breakage while maintaining reliable insulation between the winding and core body.
2Reliability
If the insulating member covers the entire core body to ensure insulation, then insulation coverage is improved, but thermal stress increases due to expansion coefficient mismatch
Solution Approach 1:
Rather than using a single continuous insulating member, the patent employs multiple segmented resin blocks positioned at critical locations where insulation is most needed (inner peripheral wall portion, outer peripheral wall portion, and tooth portions). This segmentation allows each block to independently accommodate thermal expansion without generating excessive stress, while collectively providing sufficient insulation coverage to ensure reliable electrical isolation.
3Stability of the object's composition
If the insulating member is integrated with the core body for structural stability, then structural integrity is improved, but thermal expansion differences cause stress concentration
Solution Approach 1:
The insulating member is configured as multiple separate resin blocks rather than a single integrated piece. These blocks are positioned at specific locations where insulation is critical (inner peripheral wall, outer peripheral wall, and tooth portions) but remain structurally integrated with the core body through their positioning. The segmentation allows each block to independently accommodate thermal expansion, reducing stress concentration while maintaining overall structural integrity of the stator core assembly.
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 design effectively reduces thermal stress and breakage risk of the insulating member, maintaining the space factor of the winding and ensuring reliable insulation between the winding and core body, even under varying temperatures.
Implementation Method 1
the insulating member (60) having a linear expansion coefficient different from a linear expansion coefficient of the core body (40)
Data Source
AI summary
A stator core of an electric motor includes a core body, a slot, and an insulating member. The insulating member is integrated with the core body and has a linear expansion coefficient different from the core body. The insulating member includes, at a peripheral wall portion, a plurality of contact portions extending throughout a cylinder axial direction of the stator core and being in contact with the peripheral wall portion, and a noncontact portion positioned between adjacent ones of the contact portions. The noncontact portion extends throughout the cylinder axial direction and is not in contact with the peripheral wall portion. The peripheral wall portion has an inner peripheral wall portion forming a peripheral wall of the slot, and an outer peripheral wall portion forming an outer peripheral wall of the core body. The insulating member is located at at least one of the inner and outer peripheral wall portions.