Stator Winding Joining at Slot-Accommodated Portions
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Solution Overview
Problem
Conventional rotary electric machines have a large axial size due to the projection of element wire ends, which increases the stator size and requires additional space for connection, leading to inefficiencies in downsized high-power applications.
Innovation Solution
The stator design joins first and second windings at slot-accommodated portions, reduces the number of ends projected axially, and uses welding and insulation to ensure strong and insulated connections, with cranked or staircase-shaped turn portions to minimize interference and size, while aligning windings depthwise to enhance magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three-phase stator winding is formed using twelve element wires with twenty-four element wire ends axially projected, then the connections can be established, but the axial space required for connecting increases the stator size
Solution Approach 1:
The patent merges the first and second windings for each phase by joining them at slot-accommodated portions, reducing the number of axially projected wire ends from twenty-four to a fewer number. This combining approach eliminates the need for separate connection spaces for each winding end, thereby reducing the axial length of the stator while maintaining reliable electrical connections.
Solution Approach 2:
Instead of arranging winding ends along the axial direction for connection, the patent repositions the joining location to slot-accommodated portions, effectively moving the connection point from the axial dimension to the radial/d circumferential dimension. This dimensional shift allows connections to be made without increasing axial length.
2Length of stationary object
If the stator is downsized by reducing axial projection, then the machine size is reduced, but the mechanical strength of connections may be compromised
Solution Approach 1:
The patent skips the conventional connection method at axial ends and directly joins windings at slot-accommodated portions during the winding formation process. This approach integrates the connection into the winding structure itself, providing mechanical strength through the winding tension and slot confinement rather than separate connection hardware, thus maintaining strength while reducing axial size.
Solution Approach 2:
The patent forms windings with continuous curved paths that loop through slots and accommodate portions, creating a self-reinforcing structure. The curved winding geometry distributes mechanical stress along the entire winding path rather than concentrating it at discrete connection points, enhancing connection strength without requiring additional axial space for rigid connectors.
3Length of stationary object
If windings are joined at slot-accommodated portions, then the axial size is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent incorporates the joining of first and second windings at slot-accommodated portions as a preliminary action during the winding formation process itself, rather than as a subsequent separate operation. By preparing and joining windings while they are being formed and positioned in slots, the manufacturing process integrates multiple steps, reducing overall complexity despite the innovative joining location.
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 design reduces the size of the stator and rotary electric machine without compromising performance, by minimizing the axial projection of windings and preventing interference between turn portions, thus enhancing the magnetic characteristics and mechanical strength.
Implementation Method 1
the metal conductors of the two windings are joined by welding, and thus the windings can be strongly joined to each other
Data Source
AI summary
A stator for a multiple-phase rotary electric machine is provided with a stator core with slots and a coil formed of a plurality of windings for individual phases. Each winding has slot-accommodated portions accommodated in different slots, turn portions connecting the slot-accommodated portions outside of the slots in an axial direction, and a return portion that connects two of the turn portions and changes a winding direction of the winding at given slots. The turn portions include specific turn portions which are the same in a circumferential position as the turn portion connected to one of the return portion. The first and second windings are jointed to each other via a joined portion disposed in a specific slot among the slots.