Edge-Wound Rotor Assembly for High-Speed Braze Joint Stability
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Solution Overview
Problem
High-speed wound rotors face issues with self-induced vibrations and mechanical stress due to varying tension in round wire windings, and manufacturing challenges with edge-wound coils for pole counts greater than eight, leading to insufficient braze joint spacing and lack of structural support at high rotational speeds.
Innovation Solution
A high-speed edge-wound rotor design with edge-wound coils, inner diameter pole-to-pole connections supported by a wire stack, and outer diameter connections to a flexibly supported bus bar, allowing for modular assembly and braze joints that move relative to the coils, along with flexible pole bus bars and coil supporters for mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If round wire windings are used in high-speed rotors, then the rotor can be manufactured with simple winding processes, but self-induced vibrations and mechanical stress increase due to varying tension in the windings
Solution Approach 1:
The rotor winding is segmented into discrete edge-wound coils rather than continuous round wire windings. Each coil is independently wound and positioned at the edge of the rotor, eliminating the varying tension issues of round wire windings while maintaining manufacturing feasibility through modular coil assembly.
Solution Approach 2:
The patent replaces the traditional mechanical winding process with a more structured coil assembly approach. Instead of winding wire under tension around the rotor, pre-formed edge-wound coils are positioned and secured, eliminating the mechanical stress and vibration problems associated with tensioned wire windings.
2Stability of the object's composition
If edge-wound coils are used for pole counts greater than eight, then the rotor can achieve higher structural stability, but manufacturing challenges arise due to insufficient braze joint spacing and lack of structural support
Solution Approach 1:
The patent moves the braze joints from the traditional radial direction to the axial direction by positioning coils at the rotor edge. This dimensional change provides sufficient spacing for braze joints along the axial length of the rotor, enabling manufacturing of high-pole-count rotors with adequate joint spacing and structural support.
Solution Approach 2:
The patent introduces an intermediary support structure between the coils and the rotor core. This support structure provides the necessary mechanical strength and spacing for braze joints, facilitating the manufacturing of high-pole-count rotors while maintaining structural stability.
3Device complexity
If traditional winding structures are used, then the rotor design is simpler, but the package size increases and flexibility for DC connections is reduced at high speeds
Solution Approach 1:
The patent inverts the traditional winding arrangement by placing coils at the rotor edge rather than in the center. This inversion reduces the radial space required for windings and provides better access for DC connections, reducing overall package size while maintaining design feasibility through standardized coil components.
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
Enables stable operation at speeds above 12 kRPM with reduced stress on braze joints and improved mechanical support, minimizing package size and allowing for flexible DC connections, suitable for rotors with four or more poles.
Implementation Method 1
an inner diameter coil routed to an adjacent pole and brazed to an inner diameter coil of the adjacent pole and an outer diameter coil brazed to the bus bar
Data Source
Figure 1
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AI summary
A rotor (101) having multiple poles (102) is provided and includes at each pole an end winding support (110) forming a channel, a bus bar (120) disposed in the channel and edge-wound coils (130) disposed to extend around the end-winding support and the bus bar. The edge-wound coils (130) are stacked radially and include an inner diameter coil (132) routed to an adjacent pole and brazed to an inner diameter coil of the adjacent pole and an outer diameter coil (133) brazed to the bus bar.