Variable Stiffness Vibration Damping Device Using Magnetic Fluid
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Solution Overview
Problem
Existing vibration damping devices face challenges in adjusting stiffness and damping characteristics across various frequencies, particularly struggling to enhance damping characteristics for vibrations around 10 Hz affecting riding comfort and reducing damping for vibrations around 130 Hz affecting engine sound, while also being complex and costly, especially in non-axial directions.
Innovation Solution
A variable stiffness vibration damping device is designed with an annular first support member, a second support member, annular main elastic members, a partition elastic member, communication passages, coils, and a magnetic fluid, allowing for adjustable stiffness and damping characteristics in both axial and radial directions through controlled magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stiffness and damping characteristics are adjusted by varying parameters such as anti-vibration rubber stiffness, liquid chamber volumes, orifice dimensions, and membrane stiffness, then the damping characteristics can be optimized for specific frequencies, but the adjustment range is narrow and it is difficult to achieve desired characteristics at multiple frequencies simultaneously
Solution Approach 1:
The patent applies parameter changes by utilizing the magnetic fluid's variable viscosity characteristic. By changing the magnetic field strength (applying or removing magnetic flux), the viscosity of the magnetic fluid changes, which directly adjusts the damping characteristics. This allows the same device to provide different damping levels for different vibration frequencies without changing physical dimensions or structural parameters, thereby achieving wide adaptability with simple configuration.
Solution Approach 2:
The patent replaces traditional mechanical adjustment mechanisms (such as adjustable orifices, movable partitions, or interchangeable components) with a magnetic field control system. Instead of mechanically changing the structure to adjust damping, a magnetic field is applied to change the fluid's rheological properties. This substitution eliminates complex mechanical adjustment mechanisms while achieving the same functional goal of variable damping characteristics.
2Adaptability or versatility
If active control mechanisms are introduced to directly input external energy and generate desired damping force, then high damping effect can be achieved in both steady and unsteady states, but the mechanism becomes complicated and the cost of components increases
Solution Approach 1:
The patent substitutes complex active control mechanisms (such as actuators, sensors, and control algorithms used in ACM) with a passive magnetic field system. The magnetic fluid responds automatically to applied magnetic fields without requiring feedback control systems or energy input mechanisms. This eliminates the need for complicated control systems while maintaining the ability to achieve desired damping effects.
Solution Approach 2:
The magnetic fluid system operates on self-service principle where the fluid automatically adjusts its viscosity in response to magnetic field application. The system does not require external control mechanisms to actively manage damping forces; instead, the magnetic fluid's inherent rheological properties enable it to self-adjust damping characteristics based on the applied magnetic field, eliminating complex control systems.
3Adaptability or versatility
If traditional vibration damping devices are designed to damp axial vibrations, then they can effectively handle load direction vibrations, but they cannot adjust stiffness and damping characteristics against vibrations in directions other than the axial direction
Solution Approach 1:
The patent achieves multi-functionality by using magnetic fluid that can respond to vibrations in any direction. The magnetic fluid's variable viscosity property is isotropic, meaning it provides damping control in all directions (axial, radial, and other directions) simultaneously. A single magnetic field application point can control vibrations throughout the entire fluid volume in multiple directions, eliminating the need for direction-specific damping mechanisms.
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 effectively vary stiffness and damping characteristics in both axial and radial directions as needed, simplifying the configuration and improving vibration damping across a range of frequencies, including those affecting riding comfort and engine sound, while reducing complexity and cost.
Implementation Method 1
a magnetic fluid 50 filling the first liquid chamber 18A, the second liquid chamber 18B, the first communication passage 44, and the second communication passage 49
Data Source
AI summary
A variable stiffness vibration damping device includes a first support member, a second support member, a pair of main elastic members, a partition elastic member, a first communication passage, a pair of first radial walls, a second communication passage, a coil, a yoke, and a magnetic fluid. The second support member includes an axial portion. The first communication passage is provided in one of the first support member and the axial portion such that a first liquid chamber and a second liquid chamber communicate via the first communication passage. The pair of first radial walls partition one of the first liquid chamber and the second liquid chamber into a pair of third liquid chambers. The second communication passage is provided in the one of the first support member and the axial portion such that the pair of third liquid chambers communicate via the second communication passage.