External Rotor Motor Contacting Element Axial Shielding
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Solution Overview
Problem
Electromechanical commutation in motors generates electromagnetic waves that need shielding, and existing solutions fail to effectively minimize unwanted squeaking noises caused by radial contact with the motor shaft.
Innovation Solution
A contacting element with a first non-rotatably connected section to the rotor and a second section that presses against the motor shaft's end face, providing a compressive force for permanent contact and alignment, thus reducing noise and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a contacting element is radially contacted with the motor shaft, then electromagnetic interference can be shielded, but unwanted squeaking noises occur due to uneven rubbing and sliding
Solution Approach 1:
The patent inverts the contact direction from radial to axial. The contacting element contacts the motor shaft at its end face in the axial direction, reversing the conventional radial contact approach. This inversion eliminates the squeaking noises caused by radial rubbing while maintaining electromagnetic interference shielding through the conductive contact path.
Solution Approach 2:
The patent changes the contact parameter from radial direction to axial direction. By modifying the contact orientation parameter, the patent achieves both electromagnetic interference shielding and noise reduction, as the axial contact at the end face avoids the uneven rubbing characteristic of radial contact.
2Object-affected harmful factors
If the contacting element is mounted separately, then electromagnetic interference can be shielded, but additional fastening is required and centering is difficult
Solution Approach 1:
The patent merges the contacting element with the fan wheel into a single integrated component. The contacting element is formed as one piece with the fan wheel, eliminating separate fastening operations and simplifying assembly. The fan wheel's geometric features automatically provide centering, reducing the complexity of mounting while maintaining electromagnetic interference shielding functionality.
Solution Approach 2:
The fan wheel serves multiple functions: it provides aerodynamic cooling, acts as a mounting structure, and integrates the contacting element for electromagnetic interference shielding. This multi-functionality reduces the number of separate components and simplifies the overall assembly process while achieving all required functions.
3Reliability
If the contacting element is axially pressed with prestressing force, then permanent contact is ensured, but the structure becomes more complex
Solution Approach 1:
The patent introduces dynamic prestressing through the spring element, which automatically adjusts the contact force between the contacting element and motor shaft. The spring provides continuous axial prestressing force that ensures permanent contact while accommodating variations in assembly tolerances and thermal expansion, maintaining reliability without requiring complex adjustment mechanisms.
Solution Approach 2:
The patent changes the contact state from static to dynamically adaptive by using a spring element. The spring provides a prestressing force that maintains optimal contact pressure between the contacting element and motor shaft end face, ensuring reliable electrical contact for electromagnetic interference shielding while simplifying the overall structure compared to rigid fastening systems.
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
The solution allows for easy mounting and centering of the contacting element, minimizing squeaking noises and electromagnetic interference by ensuring a stable, aligned contact between the rotor and motor shaft, while also providing a cost-effective and robust design.
Implementation Method 1
the second section presses against the motor shaft's end face, providing a compressive force for permanent contact and alignment
Implementation Method 2
unwanted squeaking noises with a radial contact are often caused by natural vibrations in which the components get caught by uneven rubbing and sliding of the radial contact on the motor shaft
Implementation Method 3
Electromechanical commutation of motors creates electromagnetic waves that are radiated into the environment. These electromagnetic waves must be shielded.
Data Source
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AI summary
The invention relates to an electric motor, in particular an external-rotor motor, comprising a rotor, a stator and a motor shaft, wherein the motor shaft has a rotation axis about which the rotor and the stator are rotatably mounted in relation to one another by means of a bearing, and wherein the motor shaft has a free end with an end face, and wherein an electrical contact-making element is arranged between the rotor and the stator. The invention proposes that the contact-making element has a first section and a second section, wherein the first section is arranged in the region of the bearing and the second section bears against the end face of the motor shaft such that it can move, in particular such that it can rotate, in relation to it.