Magnetic Seal for Magnetically-Responsive Devices
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Solution Overview
Problem
Traditional seals for magnetically-responsive systems fail to effectively prevent the migration of magnetically-responsive materials, leading to contamination and premature failure of bearings, which limits the durability and reliability of these systems.
Innovation Solution
The implementation of magnetic seals that utilize a magnetic element to generate a field, preventing the passage of magnetically-responsive medium, either by positioning a ring magnet between the rotor and shaft or using a magnetic flux core to concentrate the field and create a non-contact seal, thereby preventing contamination without affecting the operational torsional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional seals (compressed felt, labyrinth seals, radial lip seals, axial lip seals) are used to prevent MR material leakage, then some sealing effect is achieved, but the seals are susceptible to binding and seizure when contaminated by MR powders, leading to intermittent failures
Solution Approach 1:
The patent replaces traditional mechanical seals with a magnetic seal that uses magnetic fields to contain MR materials. The magnetic seal includes a magnetic element that generates a magnetic field to prevent passage of magnetically-responsive medium along the rotatable shaft, eliminating mechanical contact and the associated binding/seizure problems.
Solution Approach 2:
The patent changes the sealing mechanism from mechanical contact to magnetic field interaction. By utilizing magnetic field strength as the sealing parameter instead of mechanical friction and contact pressure, the system achieves reliable sealing without the harmful effects of MR powder contamination on mechanical components.
2Reliability
If a magnetic seal is positioned with a gap between moving components to prevent contact, then bearing protection is improved, but the magnetic seal must still effectively prevent MR material passage through the gap
Solution Approach 1:
The magnetic seal uses a magnetic field to contain MR materials across a gap without mechanical contact. The magnetic element generates sufficient magnetic field strength to prevent MR material passage through the gap while allowing the gap to exist for bearing protection and reduced friction.
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 magnetic seals effectively prevent the leakage of magnetically-responsive materials, enhancing the durability and reliability of magnetically-responsive systems by maintaining the structural integrity and operational performance of bearings, even with a gap between moving components, and can be integrated with conventional sealing features for enhanced protection.
Implementation Method 1
The magnetic seal includes a magnetic element configured to generate a magnetic field to prevent passage of magnetically-responsive medium along a rotatable shaft
Implementation Method 2
the magnetic field generator is controllable to cause the magnetically-responsive medium to align along the flux path within the void and thereby cause a change in torsional resistance of the rotor
Data Source
Figure 1
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AI summary
A magnetically-responsive device (100) comprising a magnetic seal (160, 170) configured to be positioned at or near a rotatable shaft (110) is provided. The magnetic seal (160, 170) comprises a magnetic element configured to generate a magnetic field to prevent passage of magnetically-responsive powder along the rotatable shaft (110), and further comprises a magnetic concentrator configured to concentrate magnetic flux to align a magnetically-responsive medium in an area that serves as a powder barrier. The magnetic concentrator comprises a nonmagnetic spacer positioned on a side of the magnetic element. A method for preventing passage of a magnetically-responsive powder out of a magnetically-responsive device is also provided.