Rotor Assembly Alignment for Thermal Imbalance Reduction
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Solution Overview
Problem
Electric drive machines experience thermal expansion-induced imbalances due to eccentricity and axial runout in laminated cores, leading to reversible and irreversible deformations, which affect the rotor's balance and operational quality.
Innovation Solution
The rotor design involves rectifying the axial runout of laminated core assemblies on the rotor shaft, aligning them according to their pole pair arrangement to minimize thermal expansion effects, and an assembly method that includes measuring, positioning, and fixing the rotor assemblies to account for axial runout, potentially using machine learning for improved imbalance compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If laminated cores are heated to operating temperature, then thermal expansion occurs which leads to bending moment on rotor shaft, but this causes reversible and irreversible imbalance affecting rotor quality
Solution Approach 1:
The patent applies preliminary action by performing artificial aging of the rotor assembly before final operation. This pre-heating and pre-loading process causes the laminated cores and rotor shaft to expand thermally in advance, allowing the system to settle into its thermal equilibrium state before actual use. The artificial aging process includes heating the rotor to operating temperature and maintaining it for a specified duration, which pre-establishes the thermal expansion state and reduces subsequent imbalance during operation.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying temperature parameters during artificial aging. The rotor is heated from ambient temperature to operating temperature (120-160°C) in a controlled manner, and the temperature is maintained within specific ranges for predetermined times. These parameter changes allow the material properties and dimensional stability of the laminated cores and rotor shaft to adapt to thermal conditions, reducing thermal expansion-induced imbalance during actual operation.
2Manufacturing precision
If artificial aging is performed to compensate for thermal effects, then imbalance can be corrected, but production time is increased
Solution Approach 1:
The patent applies partial action by performing artificial aging on only the rotor assembly (laminated cores and rotor shaft) rather than the entire motor. This selective aging approach focuses the thermal treatment on the specific components that experience thermal expansion, eliminating the need to age the complete motor assembly. The partial aging process reduces the overall time and energy required while still achieving the necessary balance correction for the critical rotating components.
Solution Approach 2:
The patent implements skipping by integrating artificial aging into the production flow and performing it in-line before final assembly steps. The aging process is conducted as a continuous operation rather than a separate batch process, allowing subsequent assembly operations to follow immediately after aging. This eliminates idle time between aging and assembly, and the method enables rapid heating and cooling cycles that reduce the aging duration while maintaining effectiveness.
3Ease of manufacture
If rotor assemblies are positioned without rectifying axial runout, then assembly is simpler, but thermal expansion causes bending moment and irreversible deformation
Solution Approach 1:
The patent applies preliminary action by pre-measuring the axial runout of each laminated core before assembly and using this measurement data to determine the optimal positioning of rotor assemblies on the rotor shaft. The measurement and positioning calculation are performed in advance, allowing the assembly process to simply follow predetermined positions. This preliminary measurement and planning step eliminates the need for complex real-time adjustments during assembly while ensuring that thermal expansion forces are distributed optimally to minimize bending moments.
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
This approach significantly reduces thermal expansion-induced imbalances, allowing for shorter artificial aging processes, improved rotor balance, and enhanced operational smoothness and service life.
Implementation Method 1
The laminated cores may be heated to an operating temperature of 120° C. to 160° C. The heated laminated cores are subject to thermal expansion, and the thermal expansion leads to a bending moment on the rotor shaft.
Data Source
AI summary
A rotor (1) with a rotation axis (2) is provided for an electric drive machine (3). The rotor (1) has a plurality of rotor assemblies (4), each of which has a plurality of laminated cores (5) and a number of magnets (7) corresponding to a pole pair arrangement (6). The rotor also has a rotor shaft (8) on which the rotor assemblies (4) are fixed. The rotor assemblies (4) are positioned on the rotor shaft (8) such that they are rectified in accordance with their axial runout (9), while taking into account the pole pair arrangement (6). The rotor can reduce a thermally induced change in imbalance.