Variable Stiffness Vibration Absorber Using MRE and Plate Spring
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Solution Overview
Problem
Dynamic dampers using magneto-rheological elastomers (MREs) face challenges in low-frequency applications due to heavy movable masses, difficulty in maintaining spring characteristics, temperature-induced durability issues, and unevenness in MRE characteristics during production, leading to vibration interference and noise.
Innovation Solution
A characteristic value variable dynamic vibration absorber and isolator that incorporates a magneto-rheological elastomer as a first elastic member, coupled with a second elastic member, such as a plate spring made of magnetic substance material, to form closed magnetic paths, allowing for controlled magnetic fields to efficiently manage vibration damping and reduce noise and durability concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the spring characteristics of the MRE are set low to achieve low characteristic values, then the characteristic frequency can be reduced to low frequency area, but the movable mass becomes difficult to hold and causes noise due to interference
Solution Approach 1:
The patent uses a composite elastic member consisting of both MRE and conventional spring material. The MRE portion provides magnetic field controllable elasticity for frequency adjustment, while the conventional spring portion provides reliable mechanical support and holding capability for the movable mass, thus resolving the contradiction between low frequency operation and reliable mass holding.
Solution Approach 2:
The patent changes the spring constant parameter of the elastic member by applying magnetic fields to the MRE portion. This allows dynamic adjustment of the characteristic frequency without compromising the structural integrity and mass holding capability provided by the conventional spring portion.
2Adaptability or versatility
If the MRE is used as the sole elastic member, then the characteristic frequency can be varied by magnetic field control, but temperature increase from coil heating and environment degrades the spring characteristics and reduces durability
Solution Approach 1:
The composite elastic member combines MRE with conventional spring material that has better thermal stability. The conventional spring portion serves as a thermal anchor and structural support, reducing the degradation of spring characteristics under temperature increase while maintaining the frequency variability provided by the MRE portion.
Solution Approach 2:
The conventional spring material acts as an intermediary between the MRE and the movable mass, providing thermal and mechanical stability. It mediates the temperature effects and protects the MRE from excessive thermal degradation while maintaining the overall functionality of the vibration absorber.
3Adaptability or versatility
If MRE is used as the elastic member, then the characteristic frequency can be adjusted, but unevenness in characteristics among MREs during mass production makes it difficult to manage characteristics
Solution Approach 1:
The conventional spring portion provides consistent mechanical properties that are easier to control during manufacturing. This composite structure compensates for variations in MRE characteristics, making the overall system easier to manage and produce with consistent performance across mass production.
Solution Approach 2:
The conventional spring material provides homogeneous and predictable mechanical properties that serve as a baseline, reducing the impact of MRE characteristic variations. This allows for easier quality control and characteristic management during mass production.
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 manages vibration damping characteristics, enhances durability, and achieves power-saving and efficient vibration damping by controlling magnetic fields, reducing noise and maintaining consistent performance across varying temperatures and production variations.
Implementation Method 1
a magneto-rheological elastomer as a first elastic member having elastic characteristics variable with a magnetic field
Implementation Method 2
controlling the strength of a magnetic field generated by an electric current flowing through a coil
Implementation Method 3
an electromagnet that generates a magnetic field to control the vibration characteristic value of the movable mass
Data Source
AI summary
To solve a problem, for example, in which holding a movable mass becomes difficult because the spring characteristics of a rubber constituting a basis are set low in order to set the characteristic value at a low value. In a first dynamic vibration absorber including a movable mass that is coupled to a vibration damping target member via an MRE as a first elastic member having elastic characteristics variable with a magnetic field, and being capable of varying a vibration characteristic value of the movable mass by controlling the magnetic field, the dynamic vibration absorber has a second elastic member different from the MRE, and the vibration damping target member and the movable mass are elastically-coupled to each other via the second elastic member.