Pressure-Activatable Pretensioning Element for Sealing Arrangements
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Solution Overview
Problem
Sealing arrangements in technical applications, such as vibration dampers and hydraulic actuators, face reduced service life due to friction between the sealing lip and surface, especially during no-load operations, where the sealing arrangement is not frequently actuated but must remain ready for high-pressure applications.
Innovation Solution
A sealing arrangement where the pretensioning element, subjected to operating pressure, deforms and presses the sealing lip against the surface, allowing the sealing capacity to be controlled by pressure, minimizing friction and wear through a wedge guide surface and antifriction coatings, and featuring a simple design with a small number of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing lip is continuously pressed against the sealing surface to ensure sealing capability, then the sealing capacity is improved, but the friction and wear increase, reducing service life
Solution Approach 1:
The pretensioning element is designed to be pressure-activatable, transforming the static sealing force into a dynamic one that adjusts with operating conditions. During no-load operation, the sealing lip remains lightly contacted or uncontacted with the sealing surface, minimizing friction and wear. When high pressure is applied, the pretensioning element activates and presses the sealing lip against the sealing surface, ensuring adequate sealing capacity only when needed.
2Reliability
If the sealing arrangement is designed for high-pressure applications with continuous contact, then the sealing capacity is improved, but the friction during no-load operation increases, reducing service life
Solution Approach 1:
The pretensioning element is pre-configured in the retaining groove with its pressing surface oriented toward the high-pressure region. This preliminary arrangement ensures that when pressure is applied, the element is already positioned to convert pressure into axial force that activates the sealing lip, eliminating the need for continuous contact and reducing friction during idle periods.
3Adaptability or versatility
If the pretensioning element is made elastically deformable to improve sealing adaptability, then the sealing capacity is improved, but the complexity of the device increases
Solution Approach 1:
The pretensioning element utilizes elastic deformation as a parameter change mechanism. By selecting appropriate elastic materials and dimensions, the element can deform under pressure to generate the necessary axial force for sealing, then return to its original position when pressure is released. This approach achieves adaptability without complex mechanisms, relying instead on material properties and geometric design.
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 solution enhances the sealing arrangement's service life and suitability for high-pressure applications by dynamically adjusting the contact pressure with operating pressure, reducing unnecessary wear and maintaining sealing capability even during high accelerations or velocities, while being cost-effective and easy to produce.
Implementation Method 1
is deformed upon contact with the wedge guide surface. The pretensioning element consequently forces the sealing lip of the sealing element against the sealing surface of the second machine part with a contact pressing force derived from the respective operating pressure
Data Source
AI summary
A sealing arrangement includes a first and a second machine part movable relative to each other along a motional axis. A sealing element is arranged in a press fit in a plurality of grooves of a seal-holding structure of the first machine part. A sealing lip of the sealing element extends away from the seal-holding structure in the axial direction. A pretensioning element is disposed in a retaining groove of the first machine part. The sealing lip is pretensioned against a sealing surface of the second machine part in order to seal off a high-pressure region. The retaining groove has a wedge guide surface for the pretensioning element, which wedge guide surface is arranged running obliquely at an angle α, where α<90°, to the motional axis. The pretensioning element is movable against and along the wedge guide surface to pretension the sealing lip against the sealing surface.