Non-magnetic Carrier for Rotor Position Magnet Imbalance
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Solution Overview
Problem
Existing electric motors with rotor position magnets face issues of material brittleness leading to cracks and swarf production during imbalance compensation, reducing motor functionality and requiring complex swarf removal.
Innovation Solution
A rotor with a carrier made of non-magnetically conducting material, such as brass, connected to the rotor shaft, allows for simplified imbalance compensation through openings created by drilling, milling, or cutting, preventing material loss and ensuring safe removal of swarf.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If material is removed from the rotor position magnet for imbalance compensation, then rotor imbalance is compensated, but cracks occur and parts may drop off due to brittleness of magnetic material
Solution Approach 1:
The rotor structure is segmented into distinct functional components: the rotor position magnet remains intact while imbalance compensation is achieved through separate elements (counterweights or material removal from non-magnetic portions of the rotor). This segmentation prevents damage to the brittle magnetic material while still achieving balance correction.
Solution Approach 2:
The imbalance compensation function is extracted from the rotor position magnet and implemented through separate mechanisms such as counterweights attached to the rotor shaft or material removal from the non-magnetic rotor body. This extraction preserves the integrity of the magnetic material while achieving the desired balance correction.
2Stability of the object's composition
If material is removed from the rotor position magnet for imbalance compensation, then rotor imbalance is compensated, but swarf is produced that requires elaborate removal
Solution Approach 1:
The material removal for imbalance compensation is extracted from the rotor position magnet and performed on separate non-magnetic portions of the rotor or on dedicated counterweight elements. This extraction eliminates the problem of swarf generation on the magnetic material while still achieving balance correction through the same principle of mass redistribution.
3Ease of manufacture
If the carrier is made of soft non-magnetic material like brass, then openings can be easily created for imbalance compensation, but the carrier material is removed during the process
Solution Approach 1:
The carrier material properties are specifically selected (soft, non-magnetic material like brass) to enable easy material removal through drilling, milling, or cutting. The parameter changes in material selection prioritize manufacturability of imbalance compensation features, accepting controlled material loss as a trade-off for the ability to create precise balancing openings without affecting the magnetic material.
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
Enables safe and efficient imbalance compensation in electric motors, preventing material loss and maintaining motor functionality by using a soft, non-magnetic carrier for the rotor position magnet, facilitating rapid and precise magnet placement and stable fastening.
Implementation Method 1
at least one rotor position magnet for providing a magnetic signal that can be evaluated, upon a rotation of the rotor shaft, at least for the purpose of determining a respective rotor position of the rotor
Data Source
AI summary
An electric motor includes a stator, and a rotor which has a rotor shaft. At least one rotor position magnet is disposed on the rotor shaft, and is configured to provide a magnetic signal that can be evaluated, upon a rotation of the rotor shaft, at least for the purpose of determining a respective rotor position of the rotor. At least one carrier is disposed in a rotationally fixed manner on the rotor shaft, and is connected to the at least one rotor position magnet. The carrier includes at least one opening configured to compensate imbalance of the rotor.