Frequency-Dependent Damper With Auxiliary Piston
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Solution Overview
Problem
Existing frequency-dependent dampers, such as those described in U.S. Pat. No. 5,129,488, are not capable of achieving the required damping characteristics for applications like railways, where little damping is needed at low frequencies and increased stiffness is required at high frequencies, and other technical fields with different frequency-dependent demands.
Innovation Solution
A fluid-filled damper with a throttling member comprising an auxiliary cylinder and piston, which divides the fluid flow between main chambers, allowing for adjustable damping characteristics by opening and closing fluid connections based on the movement of the piston, creating a stiff damper at high frequencies and a soft damper at low frequencies through the use of an auxiliary piston with varying cross-sections and non-return valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional damper design is used, then damping action is provided at all frequencies, but it cannot achieve the required frequency-dependent characteristics of soft at low frequencies and stiff at high frequencies
Solution Approach 1:
The damper is divided into multiple chambers (first main chamber, second main chamber, first auxiliary chamber, second auxiliary chamber) with a piston and auxiliary piston that can independently control fluid flow paths. This segmentation allows different damping characteristics to be achieved in different frequency ranges by controlling which chambers are connected.
Solution Approach 2:
The auxiliary piston is designed to move dynamically between a rest position and an activated position based on the frequency and amplitude of vibrations. At low frequencies, the auxiliary piston remains in the rest position allowing fluid communication between chambers for soft damping. At high frequencies, the auxiliary piston moves to block the opening, creating stiff damping characteristics.
2Force
If the auxiliary piston blocks the opening, then the damper provides stiff damping at high frequencies, but fluid flow between chambers is restricted
Solution Approach 1:
The auxiliary piston acts as an intermediary element that selectively controls fluid flow between chambers. It can completely block the opening to provide stiff damping when needed, while still allowing full fluid communication when the damping force is not required, thus managing the trade-off between force and fluid flow quantity.
3Adaptability or versatility
If the auxiliary piston moves to open the fluid connection, then the damping action is reduced, but the damper becomes softer at low frequencies
Solution Approach 1:
The auxiliary piston dynamically adjusts the damping characteristic based on operating conditions. When activated by high-frequency vibrations, it opens the fluid connection to reduce damping action and allow softer response. This dynamic adjustment enables the damper to adapt its force characteristics to match the required frequency-dependent behavior.
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 damper achieves the desired frequency-dependent characteristics, providing increased stiffness at high frequencies and reduced damping at low frequencies, enhancing stability in applications like railways, particularly for trains traveling at high speeds.
Implementation Method 1
the part with the relatively small bore is subjected to the fluid pressure from the one the first and second main chambers and the part with the relatively large cross-section is subjected to the fluid pressure from the other one of the first and second main chambers
Implementation Method 2
a fluid-filled, frequency-dependent damper comprising a cylinder connected to a cylinder attachment portion; a piston connected to a piston attachment portion, the piston being displaceable in the cylinder
Implementation Method 3
the damper comprises a spring configured and arranged for biasing the auxiliary piston towards the first opening by spring action of the spring
Implementation Method 4
a throttling member constructed and arranged for allowing and influencing a fluid flow between the first and second chambers within the damper
Implementation Method 5
the throttling member comprising an auxiliary cylinder and an auxiliary piston provided in the auxiliary cylinder
Data Source
AI summary
A fluid-filled, frequency-dependent damper includes a cylinder connected to a cylinder attachment portion; a piston connected to a piston attachment portion, the piston being displaceable in the cylinder; first and second main chambers; and a throttling member for allowing and influencing a fluid flow between the first and second main chambers within the damper when the cylinder attachment portion and the piston attachment portion move relative to each other.