Laminated Rotor Balancing via Stud Compression and Slot Weights
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Solution Overview
Problem
Laminated rotor bodies in electric machines are prone to deformities due to fault torques and radial runoff, requiring frequent rebalancing and lack the bending stiffness of solid steel rotors, leading to increased manufacturing costs and long lead times.
Innovation Solution
A laminated rotor structure comprising axially stacked laminations with radially extending slots, where a stud member passes through holes in the laminations, and a coil stack is positioned in fewer than all slots, with balancing members in empty slots to achieve balanced rotation and torque transmission, utilizing a high-strength stud member and compression to provide necessary bending stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If laminated rotor bodies are used to reduce manufacturing cost and lead time, then manufacturing cost and lead time are reduced, but the rotor becomes more prone to deformities and requires frequent rebalancing
Solution Approach 1:
The rotor body is segmented into multiple laminations that are stacked axially, allowing for easier manufacturing and assembly while maintaining structural integrity. This segmentation enables the rotor to be manufactured more quickly than solid steel rotors while providing flexibility to address balance issues.
Solution Approach 2:
Balance weights are selectively placed in specific slots at specific radial positions to correct imbalance without requiring complete rotor replacement or extensive rebalancing. This localized adjustment capability maintains rotor reliability while using the cost-effective laminated structure.
2Ease of manufacture
If laminated rotor bodies are used to reduce manufacturing cost, then manufacturing cost is reduced, but the rotor lacks the bending stiffness of solid steel rotors
Solution Approach 1:
The rotor combines laminated steel structure with strategically placed balance weights and coil stacks to achieve the required bending stiffness. This composite approach allows the rotor to maintain structural strength while using cost-effective laminated construction instead of expensive solid steel forgings.
Solution Approach 2:
The rotor design utilizes the axial dimension by stacking multiple laminations to achieve the required moment of inertia and bending stiffness, rather than relying solely on radial thickness. This dimensional approach allows cost-effective manufacturing while maintaining mechanical strength.
3Adaptability or versatility
If coil stacks are positioned in fewer than all slots, then manufacturing flexibility is improved, but empty slots require balancing members to achieve balanced rotation
Solution Approach 1:
The slots in the rotor serve multiple functions: they can contain coil stacks for electromagnetic functionality or balance weights for rotational balance. This multi-functionality allows the same slot structure to accommodate different configurations based on manufacturing requirements while maintaining rotor performance.
Solution Approach 2:
The balance weights placed in empty slots not only provide balancing function but also contribute to the overall structural integrity and mass distribution of the rotor. The rotor structure itself provides the mechanism for its own balancing through strategic placement of these weights in available slots.
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
The solution enhances the structural integrity and balance of the rotor, reducing the need for frequent rebalancing and achieving bending stiffness comparable to solid steel rotors, while minimizing manufacturing costs and lead times.
Implementation Method 1
a rotor body comprising a plurality of axially stacked laminations... A stud member passes longitudinally through at least one hole in the plurality of stacked laminations
Data Source
AI summary
A laminated rotor and an electric machine including the laminated rotor are disclosed. In an embodiment, a rotor comprises a plurality of stacked laminations, wherein each lamination includes a plurality of radially extending slots arranged about a circumference of each of the plurality of laminations, and the plurality of radially extending slots in successive laminations in the stack are aligned. A stud member passes longitudinally through at least one hole in the lamination stack, and a plurality of coils are positioned within the plurality of slots. Fewer than all of the plurality of slots have a coil positioned therein, leaving at least three slots empty. Balance members may be placed in the slots that do not have a coil positioned therein to balance the rotor.