Elevated Rotor Webs for Motor Strength and Magnetic Control
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Solution Overview
Problem
Existing methods for producing sheet metal parts for electric motor laminated cores lack sufficient strength and efficiency in reducing stray magnetic fields, limiting the rotational speed and torque of electric motors.
Innovation Solution
The method involves punching out sheet metal parts from a flat strip and forming them into a three-dimensional shape with elevated regions, specifically obliquely protruding rotor webs, to increase strength and reduce magnetic permeability, allowing for higher rotational speeds and torque without altering the outer diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sheet metal parts are formed as flat structures, then manufacturing is simple, but mechanical strength is insufficient
Solution Approach 1:
The patent applies dimensionality change by transitioning from flat, two-dimensional sheet metal structures to three-dimensional structures with elevated regions and varying thickness. The forming process creates protrusions and recesses that add vertical dimension, transforming the geometry from planar to spatial. This dimensional transition directly addresses the strength limitation by creating load-bearing three-dimensional structures while maintaining compatibility with standard punching and forming manufacturing processes.
2Object-generated harmful factors
If rotor webs are made thin to minimize stray magnetic field, then magnetic performance improves, but mechanical strength decreases
Solution Approach 1:
The patent applies local quality by creating regions of varying thickness and magnetic permeability within the sheet metal part. The forming process produces localized elevated regions with different magnetic properties compared to the base material. This allows certain areas to be optimized for magnetic performance (thin regions minimizing stray fields) while other areas maintain mechanical strength (thicker elevated regions providing structural support), achieving both objectives simultaneously through spatially differentiated material properties.
3Power
If higher rotational speeds are achieved, then motor output increases, but mechanical strength requirements increase
Solution Approach 1:
The patent enables higher motor output by creating three-dimensional structures that provide enhanced mechanical strength capable of withstanding higher rotational speeds. The elevated regions and varying thickness profiles create load-bearing structures that can endure the increased centrifugal forces and mechanical stresses associated with high-speed rotation, thereby allowing the motor to operate at higher speeds and deliver increased power output.
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 enhances the mechanical strength and rotational stability of electric motor rotors, enabling higher speeds and torque while minimizing stray magnetic fields and reducing magnet material usage.
Implementation Method 1
the sheet metal part is punched out of a flat sheet metal strip. To this end, the sheet metal part to be punched out is positioned between a punch and an associated die of a punching tool, wherein following this a relative movement between the punch and the die takes place in such a manner that the punching-out of the sheet metal part is carried out
Implementation Method 2
During or after the punching-out, the sheet metal part is formed at least in one region so that an elevation protruding out of a sheet metal part plane is created
Implementation Method 3
the sheet metal part is formed at least in one region so that an elevation protruding out of a sheet metal part plane is created... the magnetic permeability in the region of these rotor webs reduced
Data Source
AI summary
A method for producing a sheet metal part for a laminated core of a rotor of an electric motor, a sheet metal part, and a rotor are disclosed. The method includes punching out the sheet metal part from a sheet metal strip to provide at least two recesses and at least two rotor webs; and forming an elevation at least in one region that protrudes out of the sheet metal part with respect to a sheet metal part plane.