Hubless Rotor Lamination Assembly for Lower Weight and Cost
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Solution Overview
Problem
Conventional electric machines with rotors that include a metal hub are heavy and costly due to the need for multiple fabrication steps and materials like cast iron or steel, prompting a need for a rotor design that eliminates the central hub to reduce weight and manufacturing complexity.
Innovation Solution
A rotor design featuring a central shaft with radially extending flanges and multiple axially aligned lamination stacks that are not directly supported by the shaft, where each lamination stack is connected through fasteners and alignment pins, eliminating the need for a central hub.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a metal hub is used to support laminations, then structural integrity is maintained, but rotor weight increases
Solution Approach 1:
The patent removes the metal hub from the rotor assembly entirely. Instead of using a central metal hub to support the laminations, the design allows laminations to be directly stacked and secured to the shaft using fasteners and alignment pins. This extraction of the metal hub component directly reduces rotor weight while maintaining structural integrity through alternative fastening mechanisms.
2Ease of manufacture
If a metal hub is used to support laminations, then structural integrity is maintained, but manufacturing complexity increases
Solution Approach 1:
By removing the metal hub component entirely, the manufacturing process is simplified. The patent eliminates the need to cast or machine a complex metal hub structure, reduce it to simple fasteners and alignment pins that can be directly attached to the shaft, thereby reducing manufacturing complexity while preserving structural integrity through the fastening system.
Solution Approach 2:
The rotor assembly is segmented into discrete components: the shaft, the laminations, the fasteners, and alignment pins. This segmentation eliminates the need for a monolithic metal hub, allowing each component to be manufactured separately using simpler processes and then assembled together, thereby improving ease of manufacture while maintaining structural integrity.
3Ease of manufacture
If a metal hub is used to support laminations, then structural integrity is maintained, but production cost increases
Solution Approach 1:
The elimination of the metal hub removes a costly component from the rotor assembly. Metal hubs require expensive casting or machining operations and use of high-strength materials. By extracting this component and replacing it with simpler, cheaper fasteners and alignment pins, production costs are reduced while structural integrity is maintained through the alternative fastening system.
Solution Approach 2:
The patent replaces the expensive, durable metal hub with cheaper fasteners and alignment pins that can be easily manufactured and replaced if needed. These simpler components reduce material costs and manufacturing expenses while providing sufficient structural support for the rotor assembly.
Data Source
AI summary
A rotor includes a shaft having an outer surface including a first diameter and a flange extending from the outer surface. A first plurality of laminations is arranged about the shaft. The first plurality of laminations includes an outer annular surface and an inner surface defining an opening including a second diameter that is substantially equal to the first diameter. A second plurality of laminations is arranged about the shaft and coupled to the first plurality of laminations. The second plurality of laminations include an outer annular surface portion and an inner surface portion defining a third diameter that is greater than the first diameter.