Electric Motor Stator Touch-Down Pad for Rotor Contact Protection
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Solution Overview
Problem
In electric motors, particularly in-wheel motors, the minimized air gap between the stator and rotor can lead to friction and potential damage when the rotor strikes the stator due to distortion, thermal expansion, or shock loading, reducing efficiency and risking damage to permanent magnets and stator laminations.
Innovation Solution
Incorporating a low friction touch-down pad on the stator or rotor as the first point of contact minimizes frictional forces and protects other components by using raised surfaces made from low friction materials, such as nylon or PTFE, strategically positioned to prevent direct contact between the rotor magnets and stator teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the air gap between stator and rotor is minimized to increase flux density, then motor efficiency is improved, but friction and damage risk increase when rotor strikes stator
Solution Approach 1:
A touch-down pad made of low friction material (PTFE or nylon) is introduced as an intermediary element between the rotor and stator. This pad is strategically positioned on the stator to receive contact from the rotor during distortion events, preventing direct metal-to-metal contact and reducing friction while allowing the minimized air gap to be maintained for high efficiency operation
2Use of energy by moving object
If the air gap is minimized, then flux density is increased, but permanent magnets and stator laminations are at risk of damage during contact events
Solution Approach 1:
The touch-down pad is pre-installed on the stator in a strategic position before operation begins. This pad acts as a protective cushion that absorbs contact forces during rotor distortion events, preventing direct impact between the rotor and vulnerable components such as permanent magnets and stator laminations, thereby maintaining component durability while allowing minimized air gap for high flux density
3Ease of operation
If direct contact between rotor and stator occurs, then friction increases reducing efficiency, but no additional protection mechanism is present
Solution Approach 1:
The touch-down pad serves as a low friction intermediary surface that the rotor contacts during operation. Made from PTFE or nylon, this material significantly reduces frictional energy loss compared to direct metal-to-metal contact, while maintaining the simple operational characteristic of allowing natural rotor-stator interaction during distortion events
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 design significantly reduces friction and minimizes the risk of damage to the motor components during contact events, maintaining efficiency and extending the lifespan of the motor by allowing the touch-down surfaces to skid or slide, thus reducing frictional forces and preventing damage to magnets and laminations.
Implementation Method 1
contact between the rotor and stator will increase friction between the stator and rotor, thereby decreasing the efficiency of the motor
Data Source
AI summary
An electric motor or generator having a stator with stator teeth for mounting electrical coils and a rotor, wherein the stator has a first surface that is substantially perpendicular to an axis of rotation of the rotor and the rotor has a second surface that is formed in substantially the same radial position as the stator's first surface, wherein upon the rotor being pivoted perpendicular to the axis of rotation of the rotor the first surface and the second surface are arranged to prevent the rotor coming into contact with the stator teeth.