Cast End Shield With Waved Reinforcement For Electrical Machines
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Solution Overview
Problem
Existing end shields for electrical machines face challenges in achieving high radial stiffness and minimizing axial space while maintaining competitive manufacturing costs, as traditional thick steel sheets result in poor bending stiffness and increased material costs.
Innovation Solution
A cast end shield with a waved reinforcement structure on the intermediate rim, featuring alternate ridges and valleys, provides high global bending stiffness while optimizing material usage and reducing weight, along with reinforcement rings on the inner and outer rims to enhance support and reduce deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick steel sheet is used for end shield, then local stiffness of bearing attachment is improved, but material costs and axial space requirement increase
Solution Approach 1:
The end shield employs local reinforcement through ribs and strengthening structures positioned specifically at the bearing attachment area, rather than uniformly thickening the entire shield. This concentrates material where needed to improve local stiffness while keeping other areas thin to reduce overall weight and axial space.
Solution Approach 2:
The end shield combines thin steel sheet base material with additional reinforcement elements (ribs, strengthening structures) to create a composite structure that achieves high local stiffness at the bearing attachment without requiring the entire shield to be thick, thus reducing material costs and axial space requirement.
2Strength
If uniform thickness steel sheet is used, then manufacturing simplicity is maintained, but bending stiffness is poor in relation to weight
Solution Approach 1:
The end shield transitions from uniform thickness to variable thickness design with localized reinforcements (ribs and strengthening structures) positioned strategically to maximize bending stiffness where needed while minimizing material usage in non-critical areas, improving the stiffness-to-weight ratio.
Solution Approach 2:
The strengthening structures incorporate curved and waved reinforcement patterns rather than straight rigid elements, which provide superior bending resistance per unit of material while reducing overall weight compared to uniform thickening.
3Strength
If reinforcements are welded onto shield, then bending stiffness is increased, but manufacturing complexity and costs increase
Solution Approach 1:
The reinforcement structures (ribs and strengthening elements) are integrated into the end shield as a single monolithic casting rather than separate components requiring welding assembly. This merging of functions into one manufacturing step eliminates welding operations and reduces manufacturing complexity while maintaining the bending stiffness benefits.
Solution Approach 2:
The invention changes the manufacturing parameter from multi-stage welding assembly to single-stage casting process, producing the reinforced end shield in one operation. This parameter change reduces manufacturing complexity and costs while achieving the required bending stiffness through the cast reinforcement structures.
4Strength
If end shield thickness is increased, then radial and rotational stiffness are improved, but axial space requirement increases
Solution Approach 1:
The end shield uses localized thickening and reinforcement structures at critical areas (bearing attachment zones) rather than uniform thickening throughout. This provides the necessary radial and rotational stiffness locally where bearings are mounted while keeping the overall axial thickness minimal to reduce space requirements.
Solution Approach 2:
The end shield is segmented into different thickness zones: thin areas for non-critical regions and thickened/reinforced areas for critical bearing support zones. This segmentation allows optimization of stiffness where needed while minimizing axial space consumption in other areas.
Data Source
AI summary
A cast end shield for an electrical machine, said end shield supporting a bearing that supports the rotor, and said end shield having an opening in the middle. In the radial direction from the centre of the shield, there is an inner rim limited by the opening, an intermediate rim connected to the inner rim and an outer rim connected to the intermediate rim. The intermediate rim has at least one substantially waved reinforcement structure, and within the reinforcement structure, the valleys of the waves are substantially in the radial direction.