Internal Rotor Motor Lamination Segmentation
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Solution Overview
Problem
Existing internal rotor motors face challenges with excessive press-in forces during assembly, leading to potential damage and unreliable connections due to variations in material hardness and chip formation, particularly with notched connections.
Innovation Solution
The internal rotor motor features a laminated rotor core with optimized tooth geometry and a central recess design that allows for ideal press-in and press-out forces, minimizing chip formation and hardness-related issues, without requiring complex shaft modifications, and provides a reproducible force-displacement curve for precise analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the shaft is pressed directly into the rotor, then the connection is simple, but excessive press-in forces occur that damage the rotor and shaft
Solution Approach 1:
The rotor core is segmented into multiple laminations with alternating angular positions, creating distributed contact zones that segment the press-in force across multiple interfaces rather than concentrating it at a single location
Solution Approach 2:
Different regions of the rotor core have different angular offsets of laminations, creating local variations in contact geometry that optimize force distribution at each interface between shaft and rotor
2Stress or pressure
If notches are provided on the shaft for connection, then surface pressure is reduced, but chips are pushed off the shaft and cold welding occurs
Solution Approach 1:
The patent converts the potential harm of chip formation into a benefit by designing the lamination geometry so that material flow during pressing is controlled and directed, preventing chips from detaching and causing cold welding while still achieving low press-in forces
3Force
If notched connection is used, then press-in forces are reduced, but the joining process becomes unreliable due to hardness variations
Solution Approach 1:
The patent changes the geometric parameters of the rotor laminations (angular offsets, contact surface areas) to create a connection that is less sensitive to material hardness variations, achieving reproducible force-displacement curves despite material property variations
Data Source
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AI summary
An internal rotor motor, in particular an electronically commutated internal rotor motor, has a multi-pole stator (28) and a laminated rotor core (52, 54, 56) which is mounted such that it can rotate relative to said stator (28), and also has a central recess (47) which is provided in the laminated rotor core, wherein the laminated rotor core has individual laminations (41) and the central recesses (47) in said individual laminations have radially inner first sections (50) into which a shaft (18) is pressed, and said central recesses (47) have second sections (51) in the regions between the radially inner first sections (50), said second sections being spaced apart from the outside of the shaft (18) in the assembled state, wherein at least some of the individual laminations (41) of the laminated rotor core (52) are arranged with an angular offset in relation to one another.