Active Seal Architecture for Variable Closure Force
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Solution Overview
Problem
Conventional passive seals used in applications like vehicle doors face a tradeoff between seal effectiveness and closure effort, as increasing interface pressure or contact area enhances sealing but increases door opening and closing efforts, and they cannot be remotely controlled to alter stiffness or geometry.
Innovation Solution
Active material seal architectures that include a flexible outer layer and an interior structure with active material elements, allowing for variable sealing force and stiffness by changing the material's properties or geometry in response to external stimuli, such as electric current or temperature changes, to optimize sealing performance with minimal power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive seal assemblies are used to provide sealing engagement, then seal effectiveness is improved through increased interface pressure and contact area, but closure effort increases making door opening and closing more difficult
Solution Approach 1:
The seal assembly transitions from a static passive structure to a dynamic active system that can change its sealing properties on demand. The active material elements (such as piezoelectric, electrostrictive, or dielectric elastomer materials) allow the seal to dynamically adjust its cross-sectional geometry and stiffness in response to electrical stimuli, enabling variable sealing force without permanently increasing closure effort.
Solution Approach 2:
The invention changes the physical parameters of the seal assembly by using active materials whose elastic modulus, shape, and volume can be modified through electrical fields. This allows the seal to transition between different states (e.g., compressed vs. relaxed cross-sectional geometry) to optimize the balance between sealing effectiveness and closure effort under different operating conditions.
2Device complexity
If passive seal materials are used, then the seal structure is simple and cost-effective, but the stiffness and cross-sectional geometry cannot be remotely changed or controlled on demand
Solution Approach 1:
The invention replaces traditional mechanical adjustment mechanisms (such as adjustable bolts, levers, or mechanical actuators) with electrical field-based active materials. This substitution allows remote and precise control of the seal's stiffness and geometry through electrical signals, greatly enhancing adaptability while maintaining relatively simple seal architecture.
Solution Approach 2:
The seal assembly incorporates composite structures combining passive elastomeric materials with active material elements (such as piezoelectric ceramics, electrostrictive polymers, or dielectric elastomers). This composite approach integrates the beneficial properties of both material types: the passive materials provide structural support and sealing functionality, while the active materials enable remote control of stiffness and geometry.
3Reliability
If increased interface pressure is applied by passive seals, then sealing performance is enhanced, but the force required to open and close doors increases
Solution Approach 1:
The active seal assembly can apply sealing force periodically or intermittently rather than continuously. The control system activates the active material elements only when sealing is required (e.g., when the door reaches the closed position), allowing high sealing force to be generated on demand without requiring continuously high closure effort throughout the door operation cycle.
Solution Approach 2:
The active materials can be pre-conditioned or pre-positioned to generate sealing force at the critical moment when the door closes. The control system anticipates the closing action and activates the active elements in advance or at the precise moment needed, ensuring optimal sealing force is applied when the door contacts the seal, thereby reducing the overall force needed for door operation.
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
These active seals reduce the force required to open and close doors while maintaining sealing pressure, minimizing air bind and potentially eliminating the need for secondary seals, offering lower costs, reduced noise, and increased packaging flexibility compared to conventional actuators.
Implementation Method 1
an interior structure comprising at least one active material element... configured to impart a first force upon the layer or produce a first stiffness when the element is deactivated, and a second force upon the layer or second stiffness when activated
Data Source
AI summary
Active seal architectures adapted for producing a variable sealing and/or closing force between a closure panel and perimeter, includes a mounting clip, a flexible outer layer fixedly connected to the clip, defining an interior space, and longitudinally extending along the perimeter; and an interior structure comprising and reconfigurable by an active material disposed within the space, and operable to impart differing first and second forces upon the layer and panel when the material is activated and deactivated respectively.