Electric Motor Rotor Core with Non-Congruent Lamination Contours
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The assembly of rotor cores for electric motors is laborious, with insufficient precision in tolerances leading to the need for balancing and adjustment steps, which complicates the production process and affects the magnetic field conditions.
Innovation Solution
A rotor core design with an uneven surface formed by rotated core laminations, featuring a central recess with a non-congruent contour, allows for secure and precise attachment to the rotor shaft using transfer molding, eliminating the need for subsequent balancing and adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If individual core laminations are attached to form the rotor core on a rotor shaft, then the rotor core can be assembled, but the tolerances cannot be ascertained sufficiently precisely, requiring subsequent balancing work
Solution Approach 1:
The rotor core is pre-assembled as a complete unit with all core laminations attached to the rotor shaft before final installation. This preliminary assembly allows for precise tolerance control and balancing to be performed on the complete rotor core assembly, eliminating the need for subsequent balancing work when individual laminations are attached separately.
2Reliability
If permanent magnets are glued or clamped in peripheral receiving openings, then fixation is achieved, but precise positioning is compromised due to space requirements
Solution Approach 1:
The permanent magnets are inserted through receiving openings that pass completely through the rotor core laminations, allowing the magnets to be nested within the laminated structure. This nesting approach provides both secure fixation through the laminations and precise positioning by controlling the orientation and placement of the receiving openings in each lamination layer.
3Reliability
If receiving openings are oriented at different angles of inclination, then magnetic field conditions can be optimized, but the assembly process becomes more complex
Solution Approach 1:
Different core laminations have receiving openings oriented at different angles of inclination, creating local variations in the magnetic field path. This local quality approach optimizes magnetic field conditions in different regions of the rotor core while maintaining a systematic assembly process where each lamination is prepared with its specific orientation before stacking.
4Stability of the object's composition
If balancing weights are placed on the rotor, then rotor balance is improved, but the rotor position detection and magnetic coupling control are affected
Solution Approach 1:
Instead of adding separate balancing weights that create asymmetric mass distribution and interfere with position detection, the rotor core itself is designed with an asymmetric stack of laminations where each lamination is rotated by a specific angle. This asymmetric lamination arrangement provides both the required balance and maintains accurate position detection by keeping the magnetic structure symmetric.
Data Source
AI summary
A rotor (100) for an electric motor (1000). The rotor (100) has a rotor shaft (10) and a rotor core (20) attached onto the rotor shaft (10). The rotor core has a plurality of core laminations (40, 140) arranged along an axis (A) of the rotor core (20), and has a plurality of poles of at least one pole pair, the core lamination (40, 140) having:a central recess (70, 170) through which the rotor shaft (10) passes and which has a contour (71, 171) as well as adjacent areas (AF), and a plurality of receiving structures arranged at peripheral angular positions in order to each form a receiving element for a pole-forming element on the rotor core (20). In this context, it is provided according to the invention that the rotor core has a surface (OF) facing the rotor shaft (10) that is formed together with the adjacent areas (AF) of the central recess (70, 170) of the plurality of core laminations (40, 140), and that has uneven areas crosswise to the axis (A) of the rotor core (20) that are formed by the contours (71, 171) of the central recesses (70) of the plurality of core laminations (40, 140). The contours (71, 171) of the central recesses (70, 170) of at least a first core lamination and a second core lamination of the plurality of core laminations (40, 140) are arranged so as not to be congruent with each other.