Magnetic Braking Ring Layout for Low-Vibration Rotor Stopping
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Solution Overview
Problem
Existing magnetic braking systems for brushless synchronous motors generate mechanical vibrations and noise, which can damage bearings and reduce motor lifespan, as they struggle to effectively control rotor stopping and maintain a fixed position.
Innovation Solution
A magnetic braking device with a braking ring positioned around the rotor's braking zone, featuring a predefined gap from the motor zone to minimize axial force, using a ring with permanent magnets that generates a braking force through magnetic coupling, reducing noise and bearing damage by controlling rotor stopping and maintaining a fixed position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic brake is used to stop the rotor and hold it in a fixed position, then the rotor stopping is accelerated and the fixed position is maintained, but mechanical vibrations and noise are generated which can damage bearings
Solution Approach 1:
The rotor is divided into a motor zone and a braking zone, with the braking zone positioned on one axial end. This segmentation allows the magnetic brake to operate independently from the motor function, enabling effective rotor stopping while isolating the braking operations that generate vibrations from the motor zone, thus reducing mechanical vibrations and noise
Solution Approach 2:
A braking ring is introduced as an intermediary component between the stator and the rotor's braking zone. The braking ring, positioned around the braking zone with a predefined gap, mediates the magnetic coupling to generate braking force while the gap design controls the axial force to minimize vibrations and protect bearings
2Force
If the braking ring is positioned close to the braking zone for effective braking, then the braking force is maximized, but axial force increases causing vibrations and bearing damage
Solution Approach 1:
The position of the braking ring is optimized by establishing a predefined gap distance from the braking zone. This parameter optimization ensures that the braking force remains effective for rotor stopping while the axial force is controlled to remain below a threshold that would cause harmful vibrations and bearing damage
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 effectively reduces noise and bearing damage while ensuring smooth rotor stopping and extended motor lifespan by minimizing axial forces and vibrations, allowing for precise control of the braking ring's positioning to maintain the rotor in a stable state.
Implementation Method 1
A braking force on the rotor is generated by magnetic coupling between the at least one permanent magnet of the braking ring and the at least one permanent magnet of the braking zone
Data Source
Figure 1~2
Figure 3~4
AI summary
Magnetic braking device of a synchronous motor (100), the synchronous motor (100) comprising a rotor (110) having a motor zone (111) and a stator (120) having windings (121), an electrical supply of the windings capable of driving the rotation of the rotor (110). The magnetic braking device includes a braking zone (112) disposed at the rotor (110) in the extension of the motor zone (111) and comprising at least one permanent magnet, and a braking ring (130) comprising at least one permanent magnet, the braking ring (130) being positioned around a part of the braking zone (112) and set back, by a predefined gap (d), from the lateral edge (1121) of the braking zone (112) furthest from the motor zone, the predefined gap (d) corresponding to a distance for which a maximum axial force applied on the rotor (110) during a complete rotation of said rotor (110) is less than a predefined threshold.