Rotary Stator Segmented Coils for Slot Filling
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Solution Overview
Problem
Existing rotary electric machine stator designs face challenges such as reduced filling rate of slots, stress on windings, short-circuit risks, complex assembly, and high material waste due to the need for tooth roots and welds, which limit output and manufacturing efficiency.
Innovation Solution
A stator design featuring U-shaped conductive segments with bared surfaces that self-block and maintain contact within slots without welding, allowing for optimal tooth root retention and improved electromagnetic exchange, while minimizing material usage and assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If continuous wires are radially engaged in slots, then the winding can be formed, but the wires are subjected to stresses that risk damaging insulation coating and generating short-circuits
Solution Approach 1:
The continuous wire is divided into multiple discrete conductive segments (e.g., 5-10 segments per phase winding). Each segment is independently inserted into the slot and positioned, eliminating the stress problems associated with forcing a single continuous wire through the slot. The segments are then electrically connected through conductive adhesive, forming the complete winding without mechanical stress on insulation.
Solution Approach 2:
The mechanical connection method (physical insertion and mechanical stress) is replaced with a chemical/electrical connection method. Conductive adhesive is used to both electrically connect the segments and mechanically secure them in position, eliminating the need for forceful radial engagement that damages insulation. The adhesive forms a reliable electrical path while protecting the insulation coating.
2Ease of manufacture
If tooth roots are suppressed to allow wire introduction, then wires can be inserted, but the electromagnetic exchange between stator and rotor is reduced
Solution Approach 1:
By segmenting the winding into discrete conductive pieces, the patent eliminates the need to suppress tooth roots for wire insertion. The segments can be individually placed in slots even with prominent tooth roots present, as they are not forced through the slot in a single continuous motion. This preserves the tooth root structure and maintains optimal electromagnetic exchange between stator and rotor.
3Reliability
If slot insulation thickness is increased to prevent short-circuits, then insulation reliability improves, but the filling rate of slots is reduced
Solution Approach 1:
Replacing mechanical insertion with conductive adhesive bonding allows for thinner slot insulation. The adhesive provides both electrical connection and mechanical retention, reducing the need for thick insulation layers. This increases the slot filling rate while maintaining reliability through the adhesive's protective and conductive properties.
4Manufacturing precision
If shims are used to maintain wires in slots, then wire positioning is improved, but the filling rate of slots is reduced
Solution Approach 1:
The mechanical shim system is replaced with conductive adhesive for wire maintenance. The adhesive bonds the conductive segments directly to the slot structure, providing precise positioning without occupying additional space. This eliminates the need for shims and maximizes the slot filling rate while maintaining manufacturing precision through controlled adhesive application.
5Ease of manufacture
If multiple assembly operations are performed in situ, then the stator can be assembled, but the manufacturing complexity and time are increased
Solution Approach 1:
The conductive segments are pre-prepared with adhesive application before insertion into the slots. This preliminary action allows for efficient assembly, as the segments are ready-to-install with adhesive already in place, eliminating the need for complex in-situ assembly operations. The pre-applied adhesive ensures proper positioning and electrical connection during a single insertion step, reducing overall assembly time and complexity.
Data Source
AI summary
A stator (1) of a rotary electric machine includes a body (2) provided with slots (15), a coil (3) constituted of windings (4, 5, 6, 7, 8) that include first conductive segments (19) equipped with two first branches and second conductive segments (25) provided with two second branches. Each conductive segment is coated with insulation except for the presence of a bared surface on each one of the branches. The shapes of the bared surfaces complement one another. The first and second conductive segments are arranged in a staggered configuration and in opposite directions successively one after the other, with each slot accepting first branches and second branches positioned opposite with the bared surfaces thereof respectively in contact with one another in such a way as to form a continuous wire. The stator includes elements for keeping the bared surfaces in contact with one another in the slots.