Dynamic Damper with Closed Magnetic Circuit for Vibration Isolation
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Solution Overview
Problem
Conventional dynamic dampers face inefficiencies in vibration isolation when the frequency of disturbance vibrations differs from the eigenfrequency, and existing active mass dampers are complex and costly. Additionally, magnetic elastomers in prior art configurations are not efficiently magnetized due to magnetic flux leakage.
Innovation Solution
A dynamic damper with a non-magnetic housing, an exciting coil, and a magnetic viscoelastic elastomer forming a closed magnetic circuit using multiple magnetic members to efficiently apply a magnetic field, allowing for adjustable stiffness and enhanced vibration isolation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an electric magnet is placed near the magnetic elastomer to apply a magnetic field, then the magnetic field can be applied to the magnetic elastomer, but magnetic flux leaks to other than the magnetic elastomer, resulting in inefficient magnetic field application
Solution Approach 1:
The patent introduces a magnetic circuit including magnetic poles and a magnetic yoke as intermediary components between the exciting coil and the magnetic elastomer. The magnetic poles are in direct contact with the magnetic elastomer, and the magnetic yoke connects the magnetic poles to form a closed magnetic circuit, guiding the magnetic flux through the elastomer efficiently and preventing flux leakage to the surrounding environment.
Solution Approach 2:
The patent uses a composite structure combining non-magnetic material for the housing, magnetic material for the magnetic circuit components (poles and yoke), and magnetic elastomer as the damping element. This composite material approach allows the magnetic field to be confined and directed through the magnetic circuit while the elastomer provides the desired damping function.
2Adaptability or versatility
If a passive-type dynamic damper with fixed physical properties is used, then the device is simple and reliable, but the eigenfrequency is uniquely determined and cannot adapt when the disturbance frequency varies
Solution Approach 1:
The patent makes the physical properties of the damper dynamic by using a magnetic elastomer whose stiffness can be varied through application of a magnetic field. The exciting coil generates a magnetic field that changes the elastic modulus of the magnetic elastomer, allowing the eigenfrequency of the damper to be adjusted to match varying disturbance frequencies while maintaining a relatively simple passive device structure.
Solution Approach 2:
The patent changes the physical parameter (elastic modulus) of the magnetic elastomer by applying a magnetic field from the exciting coil. This parameter change allows the damper to adapt its stiffness and eigenfrequency to match varying operating conditions without requiring a complex active control system.
3Adaptability or versatility
If an active mass damper with actuators is used to provide arbitrary damping force, then high damping effect is achieved irrespective of disturbance state, but the device becomes complicated and cost increases
Solution Approach 1:
The patent uses a magnetic elastomer whose physical properties can be dynamically changed by applying a magnetic field from an exciting coil. This allows the damper to adapt its stiffness and damping characteristics to varying disturbance conditions without requiring complex actuators and control systems, achieving a balance between adaptability and simplicity.
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 enables efficient adjustment of the magnetic viscoelastic elastomer's properties, improving vibration isolation performance while reducing power consumption and complexity, and allowing for weight-saving and down-sizing of the device.
Implementation Method 1
an exciting coil that generates a magnetic field having an intensity corresponding to a current supplied thereto
Implementation Method 2
a magnetic viscoelastic elastomer having an elastic modulus which is variable in accordance with a magnitude of applied magnetic force
Data Source
AI summary
This dynamic damper is provided with a movable part that can be moved by external input, and an excitation coil for generating a magnetic field of an intensity corresponding to a supplied electric current. The movable part is configured to include: first and second magnetic cores in which magnetic paths, which are pathways for the magnetic field generated by the excitation coil, are configured as annular closed magnetic paths; and a magnetic viscous elastomer of which the viscous properties change in accordance with the size of the magnetic field generated by the excitation coil. The magnetic viscous elastomer is arranged so as link at least one location in the first and second magnetic cores and constitutes a closed magnetic path.