Rotor Winding Support Structure for Centrifugal and Thermal Loads
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Solution Overview
Problem
Existing electric machines face issues with rotor winding fixation, leading to adhesion failures, cohesion failures, and rotor imbalance due to centrifugal forces and thermal expansion, which can result in air gaps and reduced cooling efficiency.
Innovation Solution
A radially extending support element is placed in grooves between rotor poles, resting against a positionally-fixed thrust-bearing element, allowing the support element to expand circumferentially and press conductor loops against the rotor body, preventing radial expansion and ensuring stable fixation even at high speeds and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rotor windings are completely cast with supporting body, then mechanical fixation against centrifugal force is achieved, but residual stresses cause adhesion failure and cohesion failure leading to rotor imbalance
Solution Approach 1:
The invention divides the rotor structure into discrete segments: individual support plates positioned between specific windings and a separate casting layer. This segmentation allows each component to perform its specific function without the harmful interactions of a monolithic casting, eliminating residual stresses while maintaining mechanical fixation.
Solution Approach 2:
The support plates act as intermediary elements between the rotor windings and the casting layer. These plates provide a stable mechanical foundation that prevents the casting from generating harmful residual stresses, thereby mediating between the need for strong fixation and the need to avoid adhesion/cohesion failures.
2Strength
If support plates are used to fix rotor windings, then mechanical support is provided, but radial expansion under centrifugal force creates air gaps reducing cooling efficiency
Solution Approach 1:
The invention changes the geometric parameters of the support plates, specifically making them radially shorter than the depth of the groove. This parameter change allows the casting layer to fully fill the groove and maintain intimate thermal contact with the windings, eliminating air gaps while the support plates provide their mechanical support function.
Solution Approach 2:
The invention merges the mechanical support function of the support plates with the thermal contact function of the casting layer. The support plates provide structural support while the casting layer simultaneously provides thermal contact and additional mechanical fixation, combining multiple functions into an integrated solution.
3Strength
If casting material is used to fix rotor windings, then complete mechanical support is achieved, but costly materials and complex processes are required
Solution Approach 1:
The invention segments the fixation system into simple support plates and a thin casting layer, rather than requiring a thick, complex casting structure. This segmentation simplifies manufacturing by reducing material requirements and casting complexity while maintaining effective mechanical fixation.
Solution Approach 2:
The support plates can be made from inexpensive materials and serve their purpose effectively without requiring costly specialized casting materials. The simplified structure allows for easier manufacturing and potential replacement if needed, reducing overall system cost.
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 maintains motor functionality under extreme loads, prevents air gaps, and ensures uninterrupted heat conduction, reducing the need for costly casting materials and processes while allowing for delamination of rotor windings.
Implementation Method 1
the support element pressing the conductor loops against the rotor body during rotation and/or temperature increase of the rotor
Implementation Method 2
the support element pressing the conductor loops against the rotor body during rotation and/or temperature increase of the rotor
Implementation Method 3
ensures uninterrupted heat conduction
Data Source
AI summary
An electric machine comprises a rotor with a rotor body, wherein the rotor body has a plurality of poles each carrying at least one rotor winding formed from a plurality of conductor loops, wherein the poles extend in a radial direction of the rotor and the conductor loops running through grooves respectively formed between two adjacent poles, wherein a support element extending in the radial direction is respectively arranged in the grooves between the rotor windings of the adjacent poles, which support element, at a radially outer end of the groove, bears up against a thrust-bearing element arranged in a radially positionally-fixed manner between the adjacent poles, wherein the support element presses the conductor loops against the rotor body during a rotation and/or a temperature increase of the rotor.