Permanent Magnet Rotor Assembly Fixture Prevents Shaft Gouging
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Solution Overview
Problem
The assembly of a permanent magnet rotor with tight tolerances and clearances poses a risk of gouging the shaft when sliding components into position, due to the centrifugal forces acting on the magnets and lamination stacks.
Innovation Solution
A temporary rotor fixture with a configuration matching the rotor's ribs and overhung slots is used to assemble the magnets and C-shaped lamination stacks, with a split compression ring providing riding clearance and compression to secure the components without damaging the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If components are slid into position on the rotor shaft, then assembly is completed, but the shaft may be gouged due to centrifugal forces on magnets and lamination stacks
Solution Approach 1:
The patent applies preliminary action by pre-assembling the magnet carriers and C-shaped lamination stacks on a temporary rotor fixture before transferring them to the final rotor shaft. This preliminary assembly allows the components to be positioned and secured in a controlled environment where centrifugal forces can be managed, preventing shaft gouging during the final installation.
Solution Approach 2:
The temporary rotor fixture serves as an intermediary device between the assembly process and the final rotor shaft. It provides a stable platform for assembling the magnet carriers and lamination stacks, allowing centrifugal forces to act on the fixture rather than directly on the rotor shaft, thereby preventing damage during assembly.
2Manufacturing precision
If tight tolerances and clearances are maintained for precision, then rotor performance is improved, but assembly becomes more difficult and risky
Solution Approach 1:
The temporary rotor fixture enables preliminary assembly with precise positioning of magnet carriers and lamination stacks. This allows tight tolerances to be achieved in a controlled setting before the components are transferred to the final rotor, making precision assembly easier and safer.
Solution Approach 2:
The temporary fixture acts as an intermediary that provides stable reference surfaces and alignment features, making it easier to achieve tight tolerances during assembly. The fixture's rigid structure and precise geometry facilitate accurate positioning without the risks associated with direct assembly on the final rotor.
3Manufacturing precision
If compression is applied to secure lamination stacks, then riding clearance is achieved, but excessive force may damage components
Solution Approach 1:
The compression ring is pre-installed on the temporary rotor fixture to apply controlled compression to the C-shaped lamination stacks. This preliminary compression ensures proper riding clearance is achieved in a controlled manner, allowing adjustment and monitoring before final assembly, preventing excessive force that could damage components.
Data Source
AI summary
Apparatus for assembling a permanent magnet rotor comprising a rotor fixture configured to slide over a smaller diameter bearing section of the rotor and abutting one end of a center axial section of the rotor and a split compression ring having an inner diameter that is sized to ride over the outer diameter of magnets in magnet carriers assembled on the rotor fixture.