Frequency-Selective Damping Valve Seal Geometry
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Solution Overview
Problem
Conventional damping valve arrangements in motor vehicle vibration dampers face challenges in achieving a balance between driving safety and comfort due to undefined damping force fluctuations and reduced damping forces caused by friction variations.
Innovation Solution
A frequency-selective damping valve arrangement with a seal arrangement that increases its sealing effect with rising damping medium pressure and reduces it with falling pressure, utilizing a V-seal or four-lip seal configuration to adjust the pressing pressure of valve disks and damping force in a defined manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional seal ring is used in the control piston, then the sealing function is provided, but friction occurs during operation which reduces the preloading force on the valve disks and leads to reduced damping forces
Solution Approach 1:
The patent changes the geometric parameters of the seal ring by introducing an inclination angle α (5° to 45°) for the sealing surface relative to the axial direction. This parameter change reduces the normal force between the seal ring and control piston surface, thereby reducing friction while maintaining sealing effectiveness through the inclined contact geometry.
Solution Approach 2:
The seal ring is designed with an asymmetric cross-section featuring an inclined sealing surface rather than a symmetric circular cross-section. This asymmetric geometry allows the sealing force to be directed at an angle, reducing the axial friction component while maintaining radial sealing pressure, thus resolving the contradiction between sealing and friction reduction.
2Reliability
If a conventional seal ring is used in the control piston, then the sealing function is provided, but variations in frictional force lead to unwanted fluctuations in damping force
Solution Approach 1:
By changing the sealing surface inclination angle α to a specific range (5° to 45°), the patent stabilizes the frictional force characteristics. The inclined geometry ensures more consistent contact pressure distribution during operation, reducing variations in frictional force and thereby stabilizing the damping force output.
Solution Approach 2:
The inclined seal ring geometry creates a self-regulating mechanism where pressure variations automatically adjust the contact force distribution. When pressure increases, the inclined surface geometry naturally distributes the load to maintain consistent friction characteristics, providing a passive feedback mechanism that stabilizes damping force.
3Reliability
If the damping valve arrangement is adjusted to be hard with high damping force characteristic, then driving safety is improved, but driving comfort deteriorates
Solution Approach 1:
The patent enables dynamic adjustment of the damping valve arrangement through the control piston mechanism. The inclined seal ring allows smooth control of the control piston position, enabling continuous variation of the damping force characteristic between soft and hard settings, thus allowing the system to adapt between safety and comfort requirements.
Solution Approach 2:
The damping force characteristic is adjusted by changing the position of the control piston, which varies the preloading force on the valve disks. The inclined seal ring enables precise and stable control of this parameter, allowing the system to switch between high damping force (safety) and low damping force (comfort) modes as needed.
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 stabilizes damping forces by adjusting the sealing effect based on pressure changes, enhancing the control over damping force characteristics and reducing unwanted fluctuations, thereby improving the balance between safety and comfort.
Implementation Method 1
the seal arrangement constructed so as to increase its sealing effect with rising damping medium pressure in the control space and reduce its sealing effect with falling damping medium pressure in the control space
Implementation Method 2
When a conventional seal ring is used, it cannot be ruled out that a higher friction occurs during operation, which reduces the preloading force on the valve disks of the check valve
Data Source
AI summary
A frequency-dependent damping valve arrangement of a vibration damper having a damping piston with at least one check valve, a control arrangement arranged coaxial to the damping piston including a control pot with a pot wall and a control piston axially displaceably arranged in the control pot that axially limits a control space. The control piston has a seal arrangement that seals the control piston relative to the pot wall including a circumferential groove formed at the control piston and a seal ring arranged therein. The seal arrangement is constructed such that this seal arrangement increases its sealing effect with rising damping medium pressure in the control space and reduces its sealing effect with falling damping medium pressure in the control space.