Rotor Wedge Element Structure for Field Coil Insulation Retention
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Solution Overview
Problem
In rotary electric machines for electric or hybrid vehicles, the high-speed rotation of the rotor can cause centrifugal forces to weaken the electrical insulation of the field coil, potentially leading to short-circuits or tooth breakage.
Innovation Solution
The rotor incorporates wedge elements with convex and projecting portions that complement the rotor teeth, providing a mechanically sealed interface with potting material and ensuring the fixation of the field coil, thus enhancing insulation and mechanical holding without additional sealing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the rotor rotates at high speeds, then the mechanical power transmission is improved, but the centrifugal forces weaken the electrical insulation of the field coil and may cause short-circuits or tooth breakage
Solution Approach 1:
The field coil is impregnated with potting material before the rotor operates at high speeds. This preliminary impregnation creates a protective encapsulation that prevents centrifugal forces from damaging the electrical insulation during operation, thus maintaining reliability while enabling high-speed power transmission
2Reliability
If end caps are mounted on both axial ends of the rotor body and the field coil is impregnated with resin, then the fixation of the field coil is improved, but the manufacturing complexity and production cost increase
Solution Approach 1:
The invention removes the end caps from the rotor structure, retaining only a single end cap at one axial end. The field coil fixation is achieved through potting material impregnation and the retained end cap, eliminating the need for two end caps and reducing manufacturing complexity while maintaining adequate fixation reliability
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 solution effectively seals the interface between wedge elements and the rotor body, preventing leaks and enhancing the mechanical support of the field coil against centrifugal forces, while simplifying manufacturing by eliminating the need for additional sealing materials.
Implementation Method 1
the rotor is designed to rotate at high speeds, which may affect the holding of the field coil due to centrifugal forces
Data Source
AI summary
A rotor including a rotor shaft, a rotor body formed of a stack of laminations having a plurality of teeth projecting radially, a field coil wound around each tooth of the plurality of teeth, and a plurality of wedge elements each having two lateral sides configured to come against respectively a corresponding tooth. A convex portion and a projecting portion adjoining the convex portion are arranged on each one of the two lateral sides of the corresponding wedge element, the convex portion complementing a corresponding concave portion of the corresponding tooth, and the projecting portion coming against a corresponding protruding portion of the corresponding tooth. The projecting portion is configured to exert a pressing force on the protruding portion such that to press the convex portion against the concave portion.