Liquid Sealed Mount With Segmented Support For Vibration Damping
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Solution Overview
Problem
Existing liquid-sealed mounts for construction machines face issues with vibration absorption and damping, particularly with high-frequency vibrations, leading to cavitation and reduced damping properties, and they restrict large strokes due to high stiffness, resulting in inadequate vibration absorption and durability.
Innovation Solution
A liquid-sealed mount design featuring a cup-shaped housing, a stud, a cap member, a diaphragm separating a liquid chamber and an air chamber, and a support member that transmits loads to the air chamber, allowing relative displacement and inhibiting cavitation, while controlling pressure to maintain damping properties and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the support member is made pliable to allow large strokes, then the vibration absorption capability is improved, but the stiffness is reduced which leads to insufficient damping of high-frequency vibrations
Solution Approach 1:
The support structure is segmented into two distinct components: a pliable support member (rubber or elastomer) that provides large stroke capability, and a stiff rod member that provides damping for high-frequency vibrations. This segmentation allows each component to specialize in one function without compromising the other.
Solution Approach 2:
The pliable support member and stiff rod member are combined into a single integrated support structure. The rod member is positioned within or alongside the pliable member, creating a composite structure that simultaneously provides both flexibility for large strokes and stiffness for high-frequency damping.
2Loss of energy
If the liquid is highly viscous to provide good damping properties, then the damping capability is improved, but cavitation occurs at high vibration frequencies which reduces damping effectiveness
Solution Approach 1:
The liquid viscosity is optimized for specific local conditions: highly viscous liquid is used in regions where low-frequency damping is needed, while the system design accounts for cavitation risks in high-frequency regions through the complementary rod member structure. This local optimization allows the liquid to provide effective damping where appropriate without suffering from cavitation limitations.
Solution Approach 2:
The rod member acts as an intermediary element that supplements the liquid damping mechanism. When the highly viscous liquid experiences cavitation at high frequencies, the rod member provides alternative damping through its structural flexibility, ensuring continuous damping effectiveness across all frequency ranges.
3Loss of energy
If the liquid chamber is sealed to maintain pressure for damping, then the damping properties are improved, but the structure becomes more complex and durability is reduced
Solution Approach 1:
The liquid chamber is bounded by flexible diaphragms instead of rigid sealed containers. These thin film diaphragms maintain the necessary pressure for liquid damping while being inherently more durable and less complex than traditional sealed pressure vessels. The flexibility of the diaphragms also allows for pressure equalization and reduces stress concentration.
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 design enables effective absorption of small amplitude and high-frequency vibrations, allows large strokes, and prevents cavitation, thereby enhancing durability and maintaining high damping properties, even under high-frequency vibrations.
Implementation Method 1
the vibration absorbed by the spring is damped by a flow resistance of the liquid when the movable damping plate connected to the stud is moved in the highly viscous liquid
Implementation Method 2
the vibration in up and down direction of the cab applied to the vehicle body frame is absorbed mainly by elastic deformation of the spring
Implementation Method 3
a diaphragm separating a liquid chamber and an air chamber
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
[Object] To provide a durable liquid-sealed mount that allows a relative displacement between a stud and a housing, i.e., large strokes, has good cushioning properties, has good damping properties by inhibiting cavitation from generating even if high frequency vibration is introduced, and can still absorb small amplitude and high frequency vibration. [Solving Means] A liquid-sealed mount 1 is attached between a first member and a second member for controlling vibration introduced to the first member or the second member and includes a cup-shaped housing 10, a stud 20, a cap member 30, a diaphragm 40, highly viscous liquid 50, air, a movable damping plate 70, and a support member 80. The support member 80 is positioned between a lower end of the stud 20 or the movable damping plate 70 and the diaphragm 40 and transmits a load in a compression direction applied to the stud 20 to the diaphragm 40.