Magnetorheological Bushing Structure for Variable Axial and Radial Stiffness
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Solution Overview
Problem
Existing liquid filled bushings have constant vibration absorbing/damping characteristics in both axial and orthogonal directions, which cannot be varied during use, limiting their adaptability and effectiveness.
Innovation Solution
A variable stiffness bushing design featuring an inner and outer tubular member, elastic member with axially separated liquid chambers, a communication passage, and a coil to control the magnetic fluid's flow resistance by varying the magnetic field, allowing axial and radial stiffness to be adjusted by controlling the electric current supplied to the coil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the bushing uses a fixed gap and constant viscosity liquid, then the manufacturing is simple, but the stiffness cannot be varied during use
Solution Approach 1:
The patent changes the viscosity parameter of the filling liquid by using magnetorheological fluid whose viscosity can be dynamically adjusted through magnetic field application. This allows the stiffness of the bushing to be varied during use without changing the physical structure of the bushing itself.
Solution Approach 2:
The patent replaces the traditional mechanical adjustment method (changing gap size or liquid viscosity through mechanical means) with a magnetic field-based control system. The coil generates a magnetic field that directly influences the magnetorheological fluid's properties, eliminating the need for mechanical adjustment mechanisms.
2Adaptability or versatility
If the bushing uses a variable stiffness mechanism, then the stiffness can be adjusted, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical variable stiffness mechanisms with a simpler electromagnetic control system. A coil generates a magnetic field that directly modifies the fluid properties, providing stiffness control without mechanical linkages, actuators, or moving parts in the control system.
Solution Approach 2:
The magnetorheological fluid acts as an intermediary between the magnetic field and the mechanical stiffness. The coil generates a magnetic field that doesn't directly affect the mechanical structure but instead modifies the fluid's viscosity, which in turn controls the bushing's stiffness through the fluid's interaction with the fixed mechanical components.
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
Enables the bushing to dynamically adjust its axial and radial stiffness and damping characteristics in response to displacement, enhancing its vibration absorption capabilities and adaptability.
Implementation Method 1
a magnetic fluid (37) filling the at least one pair of liquid chambers and the communication passage
Implementation Method 2
a coil (12) wound coaxially with and provided in the one of the inner tubular member and the outer tubular member
Implementation Method 3
the pair of first walls and the second wall are configured such that when the inner tubular member and the outer tubular member are axially displaced relative to each other, a difference is created between volumes of the at least one pair of liquid chambers
Data Source
AI summary
A variable stiffness bushing includes: inner and outer tubular members; and an elastic member connecting these tubular members. At least one pair of liquid chambers axially separated from each other is defined in the elastic member. The liquid chambers are connected by a communication passage including a circumferential passage provided in one of the inner and outer tubular members. The one of the inner and outer tubular members includes a coil wound coaxially therewith and a yoke provided with a gap constituting the circumferential passage. A magnetic fluid fills the liquid chambers and the communication passage. Upper and lower end walls and an axially intermediate partition wall of the elastic member are configured such that when the tubular members are axially displaced relative to each other, a difference is created between volumes of the axially separated liquid chambers.