MRE Bushing Coil Layout for High Flux and Lower Heat
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Solution Overview
Problem
Existing magnetorheological elastomer (MRE) applications face challenges in achieving high magnetic flux density while minimizing heat generation and maintaining effective adhesion, particularly in semi-active suspension bushings (SSBs), due to competing factors such as magnetic flux density, heat output, and structural constraints.
Innovation Solution
The design positions MRE along the magnetic axis of an electromagnetic coil without appreciable magnetic shielding, using a non-magnetic interlayer and high permeability materials to enhance magnetic flux density and reduce heat generation, while ensuring effective adhesion through specialized assembly techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a large, multi-turn coil is used to generate high magnetic flux density for effective MRE performance, then the magnetic flux density increases, but significant heat output is generated that can degrade the MRE
Solution Approach 1:
A non-magnetic interlayer is introduced between the electromagnetic coil and the MRE material. This interlayer acts as a thermal barrier to reduce heat transfer to the MRE while allowing the magnetic field to pass through, thereby decoupling the thermal and magnetic interactions. The interlayer material is specifically selected to be non-magnetic to avoid interfering with the magnetic flux density generation.
Solution Approach 2:
The harmful thermal effect is extracted and isolated from the MRE system by positioning the heat-generating coil away from the MRE material, separated by the non-magnetic interlayer. This spatial separation allows the magnetic field benefit to be retained while the thermal harm is removed or minimized.
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 configuration achieves a 24% increase in average magnetic flux density and significantly reduces heat generation, enabling efficient control of MRE stiffness and damping properties, with improved thermal management and adhesion, suitable for various applications including vehicle suspensions and machinery isolation.
Implementation Method 1
an electromagnetic coil... without appreciable magnetic shielding between the coil and the MRE
Implementation Method 2
Magnetorheological Elastomers (MREs) constitute a group of materials referred to as 'smart' materials. These materials exhibit field-dependent material properties which include change in damping and stiffness properties of the material when subjected to an external magnetic field
Implementation Method 3
using a non-magnetic interlayer and high permeability materials to enhance magnetic flux density
Data Source
AI summary
An isolator designed through the inclusion of a magnetorheological elastomer (MRE) along and at or near an electromagnetic coil. A variety of factors can be balanced to produce an isolator that takes advantage of the radially axial coil. One non-limiting embodiment of the design uses a two-part coil bobbin geometry; wherein the axial center of the bobbin is a nonmagnetic material which allows passage of the magnetic field, while the end pieces are made of a high permeability material that limits the stray magnetic field and improves the magnetic flux density through the MRE by providing a pathway of least magnetic reluctance. The MRE changes stiffness and damping properties in response to the strength of the magnetic field, which can be controlled by changing the current through the electromagnetic coil. Feedback and feedforward control systems can allow for real time adaptation by the isolator in response to changing external stimuli. The isolator is useful for a variety of uses. Non-limiting examples are for reducing whole body vibrations for operators of trucks and heavy machinery, as well as for creating greater comfort for patients in ambulance gurneys and passengers in airplane seats.