Rotor Balancing via Segmented End Disk Recesses
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Solution Overview
Problem
High-speed electrical machine rotors often suffer from imbalances leading to vibrations and increased wear, particularly at critical speeds, due to uneven mass distribution and misalignment of magnets, which existing balancing methods fail to adequately address.
Innovation Solution
The rotor design features axially arranged permanent magnets with offset rows, end disks with annular elevations and recesses for prefabricated balancing masses, and engagement elevations to enhance bandage tension and radial fixation, allowing for automated balancing and improved centrifugal force absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If paste-like balancing compound is stuck to the rotor end disk, then balancing is achieved, but manufacturing precision and reliability are compromised due to imprecise mass distribution
Solution Approach 1:
The end disk is segmented into multiple recesses that can accommodate separate balancing masses. This allows precise placement of discrete balancing masses at specific angular positions, replacing the imprecise paste-like compound application with structured, measurable mass distribution.
Solution Approach 2:
The invention changes the physical state of balancing material from a paste-like compound to solid prefabricated balancing masses. This parameter change enables precise mass measurement and positioning, significantly improving manufacturing precision while maintaining balancing reliability.
2Reliability
If magnets are distributed axially along the rotor length, then magnetic field coverage is improved, but gaps remain between magnets and end plates due to tolerance accumulation
Solution Approach 1:
The invention addresses the gap problem by transitioning from purely axial magnet distribution to a combined axial and radial arrangement. Magnets are positioned in multiple axial rows with radial offset, allowing end plates to contact magnet surfaces and eliminate gaps through radial positioning rather than relying solely on axial tolerance control.
Solution Approach 2:
The magnet arrangement uses asymmetric positioning where adjacent magnet rows are offset from each other in the axial direction. This asymmetric configuration allows end plates to make contact with magnet surfaces at different axial positions, eliminating gaps caused by tolerance accumulation while maintaining comprehensive magnetic field coverage.
3Strength
If bandage is applied under pretension to fix magnets, then radial fixation is achieved, but bandage pulls into circumferential gaps limiting tensile stress application
Solution Approach 1:
The asymmetric axial offset of magnet rows eliminates continuous circumferential gaps, creating a stepped contact surface for the bandage. This allows the bandage to be applied with higher pretension without pulling into gaps, significantly improving radial fixation strength while reducing structural complexity.
4Power
If rotor operates at critical speed to achieve high performance, then power output is improved, but vibrations and wear increase due to imbalance resonance
Solution Approach 1:
The invention implements balancing masses in the end disks that act as counterweights to compensate for rotor imbalance. By precisely positioning these masses opposite to the imbalance direction, the rotor can operate at critical speeds without experiencing excessive vibrations and wear, enabling high power output while eliminating harmful resonance effects.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
In summary, the invention relates to a rotor (1) which has a first end disk (4) on one end face and a second end disk (5) on the other end face, as well as a method and a device for balancing such a rotor (1).In order to create rotors (1) for electrical machines which can be balanced particularly easily, it is proposed that the first end disk (4) and the second end disk (5) each have an annular projection, wherein the annular projection is arranged on the end face of the respective end disk (4, 5) that points away from the rotor (1), wherein the annular projection is formed from at least two cylindrical shells (11) concentric to the rotor axis and recesses (8) arranged between the cylindrical shells (11), which are separated from each other by separating elements (12), wherein the recesses (8) are each shaped in such a way that at least one prefabricated balancing mass (20) can be arranged in them.