Variable Stiffness Vibration Damping Device Using Magnetic Fluid
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Solution Overview
Problem
Existing liquid-filled vibration damping devices face challenges in adjusting stiffness and damping characteristics across various frequencies, limiting their effectiveness in absorbing vibrations at specific frequencies, such as those affecting riding comfort and engine sound, and require complex mechanisms and increased costs for active control systems.
Innovation Solution
A variable stiffness vibration damping device utilizing a magnetic fluid-filled system with a coil and yoke configuration, where the magnetic field varies the flow resistance of the fluid in communication passages, allowing for adjustable stiffness and damping characteristics by controlling the electric current through the coil, enabling simple and effective frequency-specific vibration management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stiffness and damping characteristics are adjusted by varying parameters such as the volume of liquid chambers, diameter and length of orifice, and stiffness of membrane and diaphragm, then the resonance frequency can be adjusted, but the adjustment range of stiffness and damping characteristics is narrow and it is difficult to achieve desired characteristics at arbitrary frequencies
Solution Approach 1:
The patent applies parameter changes by utilizing the magnetic fluid's variable viscosity characteristic. By changing the magnetic field strength (applying different currents to the coil), the viscosity of the magnetic fluid changes, which directly adjusts the damping characteristics and stiffness of the vibration damping device. This allows continuous adjustment over a wide range without mechanical complexity.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms (such as movable membranes, adjustable orifices, or active control actuators) with a magnetic field-based system. The coil generates a magnetic field that acts on the magnetic fluid, substituting mechanical adjustment with electromagnetic control, thereby simplifying the device structure while achieving wide-range stiffness and damping adjustment.
2Reliability
If active control mounts with actuators are used to forcibly vibrate mass elements, then high damping effect can be realized in steady and unsteady states, but the mechanism for directly inputting external energy becomes complicated and the cost of components increases
Solution Approach 1:
The patent replaces mechanical actuators and complex active control mechanisms with a magnetic field-based damping system. The coil generates a magnetic field that directly affects the magnetic fluid's viscosity, providing damping control without mechanical moving parts or complex control systems, thereby reducing component cost and simplifying the device while maintaining effective damping performance.
Solution Approach 2:
The patent changes the physical parameter (viscosity) of the magnetic fluid through magnetic field application. By varying the current through the coil, the magnetic field strength changes, which continuously adjusts the magnetic fluid's viscosity and thus the damping characteristics, achieving reliable damping control without complex mechanical systems.
3Ease of operation
If the magnetic fluid-filled system with coil and yoke is used to vary flow resistance in communication passages, then stiffness and damping characteristics can be adjusted by controlling electric current, but additional magnetic components are introduced
Solution Approach 1:
The patent makes the magnetic components serve multiple functions. The coil not only adjusts the damping characteristics by changing magnetic fluid viscosity, but also the yoke and magnetic gaps are integrated into the existing support member structure, allowing the magnetic system to perform both structural support and active damping control functions simultaneously, thereby minimizing additional complexity.
Solution Approach 2:
The patent merges the magnetic field generation system with the existing structural components. The coil is wound around the support member, and the yoke is integrated into the support member structure, combining the magnetic damping control system with the mechanical support structure, thereby reducing the number of separate components while achieving ease of operation.
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 device can dynamically adjust stiffness and damping characteristics in both axial and radial directions, enhancing vibration absorption across a wide frequency range with a simplified configuration, thereby improving riding comfort and reducing noise, while minimizing the complexity and cost of control systems.
Implementation Method 1
a magnetic fluid (50) filling the first liquid chamber (18A), the second liquid chamber (18B), and the first communication passage (44)... flow resistance of the magnetic fluid in the first circumferential passage (41) is varied by lines of magnetic force passing through the first circumferential passage (41)
Data Source
AI summary
A variable stiffness vibration damping device includes a first support member, a second support member, a main elastic member, a diaphragm, a partition elastic member, a first communication passage, a coil, a yoke, and a magnetic fluid. The first communication passage is provided in one of the first support member and the second support member such that a first liquid chamber and a second liquid chamber communicate with each other via the first communication passage. The first communication passage includes a first circumferential passage. The coil is wound coaxially with the one of the first support member and the second support member. The yoke is included in the one of the first support member and the second support member and forms a first magnetic gap overlapping at least partially with the first circumferential passage.