Rotary Electric Machine Stator Air Bubble Removal
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Solution Overview
Problem
Air bubbles forming during resin molding in rotary electric machine stators can lead to decreased insulation properties and reduced strength of the molded portion.
Innovation Solution
A rotary electric machine stator design that includes a first member with communication portions, such as grooves, which allow air bubbles to be removed from the molded resin portion, improving insulation and strength by facilitating the removal of air bubbles and preventing resin from remaining in molding equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If resin molding is performed over the coil end, then the insulation properties and strength are improved, but air bubbles form in the molded portion
Solution Approach 1:
A communication portion is formed in the first member (retaining member) before resin molding to provide a predetermined communication path. This preliminary structure enables air bubbles to escape during the subsequent molding process, preventing void formation while maintaining the insulation and strength benefits of resin molding.
Solution Approach 2:
The communication portion acts as an intermediary channel between the interior and exterior of the molded portion. It provides a controlled path for air bubbles to escape during resin injection, mediating between the need for complete resin filling and the need to eliminate air pockets that would compromise quality.
2Reliability
If resin molding is performed over the coil end, then the insulation properties are improved, but the molded portion may not be sufficiently strong
Solution Approach 1:
The communication portion is pre-formed in the retaining member before molding to ensure air bubbles can escape during resin injection. This preliminary preparation prevents void formation that would otherwise compromise both insulation properties and structural strength, ensuring the molded portion achieves sufficient strength while maintaining reliability.
3Reliability
If a communication portion is added to remove air bubbles, then the insulation properties and strength are improved, but the device complexity increases
Solution Approach 1:
The communication portion is integrated into the first member (retaining member) that already exists in the stator assembly. By combining the air escape function with the existing retaining structure, the design avoids adding separate components, thereby improving reliability without significantly increasing device complexity.
Solution Approach 2:
The first member serves multiple functions: it retains power cables, provides structural support, and now also includes the communication portion for air bubble removal. This multi-functionality eliminates the need for separate air escape mechanisms, improving insulation properties and strength while maintaining simple device structure.
Data Source
Figure 1(a)~1(b)
Figure 2A~2D
Figure 3(a)~3(c)
AI summary
A rotary electric machine includes a stator core, a coil, and a molded portion. The stator core includes an annular yoke and a plurality of teeth. The teeth protrude radially inward from the annular yoke. The coils are wound around the teeth respectively. The coil includes a coil end that protrudes toward an axially outer side from an axially end surface of the stator core. The molded portion is a resin member that covers the coil end. The molded portion includes a first member. The first member includes a communication portion that communicates inside of the molded portion with outside of the molded portion.