Vibration Damper Asymmetry Control via Segmented Check Valves
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Solution Overview
Problem
Existing vibration damper arrangements for motor vehicles face challenges in achieving desired asymmetry between rebound and compression stages, which are dependent on piston rod cross-sections, leading to inconsistent driving comfort and requiring complex seals and separate damper arrangements for each piston rod cross-section.
Innovation Solution
The use of at least two check valves and two electro-rheological or magneto-rheological operating valves allows for independent control of asymmetry between compression and rebound stages, decoupling pilot pressure from operating pressure, enabling geometry-independent asymmetry settings with a low pilot pressure of up to 10 bar, and precise control of damping actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high pilot pressure of 20-30 bar is used in the gas pressure accumulator, then cavitation in the rebound chamber is prevented, but the seal becomes complicated and subject to increased wear due to high friction
Solution Approach 1:
The circuit is segmented into multiple independent pathways using check valves and controllable operating valves. The first check valve separates the gas pressure accumulator from the compression chamber, while the second check valve separates the rebound chamber from the compression chamber. This segmentation allows low pilot pressure in the accumulator while maintaining high operating pressure in the chambers, preventing cavitation without requiring complex high-pressure seals.
Solution Approach 2:
Check valves act as intermediaries that decouple the pressure systems. The first check valve mediates between the gas pressure accumulator and compression chamber, allowing pressure equalization only in one direction. The second check valve mediates between the rebound chamber and compression chamber, enabling controlled pressure transfer. This intermediary mechanism allows the use of low pilot pressure while maintaining cavitation-free operation.
2Strength
If different piston rod cross-sections are used for different vehicle configurations, then mechanical loading requirements are met, but the asymmetry between rebound and compression directions cannot be consistently controlled, requiring separate damper arrangements
Solution Approach 1:
The damping characteristics are made dynamically adjustable through controllable operating valves that can change their flow resistance based on control signals. The first controllable operating valve controls flow between the compression chamber and gas pressure accumulator, while the second controllable operating valve controls flow between the rebound chamber and gas pressure accumulator. This dynamic control allows consistent asymmetry adjustment regardless of piston rod cross-section, enabling a single homogeneous damper design to serve multiple vehicle configurations.
Solution Approach 2:
The damping asymmetry is controlled by changing the flow parameters through the controllable operating valves rather than being fixed by the mechanical geometry. By adjusting the valve opening degrees and control pressures, the effective flow areas and pressure drops can be modified to achieve desired asymmetry ratios. This parameter-based control decouples the damping characteristics from the piston rod cross-section, allowing consistent performance across different mechanical configurations.
3Ease of manufacture
If a homogeneous damper design is used for different vehicle configurations, then manufacturing complexity is reduced, but precise control of damping asymmetry becomes more difficult
Solution Approach 1:
The control system incorporates feedback mechanisms where control signals are adjusted based on the actual damping force and vehicle conditions. The controllable operating valves receive control inputs that modify their opening degrees to achieve target damping characteristics. This feedback control compensates for the homogeneous design, allowing precise asymmetry adjustment regardless of the single fixed geometry, thereby maintaining ease of manufacture while achieving operational precision.
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
This solution allows for homogeneous damper designs that can be used across different vehicle configurations, reducing the risk of cavitation and enabling precise control of damping actions without changing mechanical properties, thus improving driving comfort and reducing the need for multiple damper arrangements.
Implementation Method 1
a first controllable electro-rheological operating valve (12) and, following this, a second controllable electro-rheological operating valve (13)
Implementation Method 2
at least two check valves and two electro-rheological or magneto-rheological operating valves
Implementation Method 3
A first check valve (6) which opens or can open toward the compression chamber (4) and a second check valve (7) which opens or can open toward the rebound chamber (5)
Implementation Method 4
the compression chamber (4) is connected via a first check valve (6) which opens or can open toward the compression chamber (4) to a gas pressure accumulator (8)
Implementation Method 5
an axially displaceable piston (2) which divides the pressure medium cylinder (1) into a compression chamber (4) and a rebound chamber (5)
Data Source
AI summary
The invention relates to a vibration damper arrangement, in particular for damping compression and rebound forces on motor vehicles, which comprises a pressure medium cylinder (1), in which a piston (2) with a piston rod (3) is guided axially displaceably, which piston (2) divides the pressure medium cylinder (1) into a compression chamber (4) and a rebound chamber (5), a gas pressure accumulator (8) also being provided for volume compensation of the piston rod (3), which gas pressure accumulator (8) is connected to the compression chamber (4) by way of at least one first check valve (6) which can open toward the compression chamber (4), and a second check valve (7) which can open toward the rebound chamber (5) and, parallel thereto, at least one first controllable operating valve (12) being provided between the compression chamber (4) and the rebound chamber (5).