SMA-Actuated Pneumatic Valve Using Membrane Pressure Assist
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Solution Overview
Problem
Existing pneumatic valves for filling elastic cushions in vehicles require large valve cross sections and high actuating forces due to high volumetric flow rates, leading to increased costs and space requirements, and existing solutions either increase costs or complicate sealing mechanisms.
Innovation Solution
A pneumatic valve design featuring a sealing element that opens a trigger opening with an actuator, utilizing the pressure difference across a membrane to minimize the force required for actuation, with passage openings between valve regions allowing fluid flow without needing additional sealing for the SMA actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large valve cross sections are used to achieve high volumetric flow rates, then the volumetric flow rate is improved, but the actuating force and sealing force requirements increase
Solution Approach 1:
The patent introduces a trigger opening and sealing element as intermediary components between the actuator and the main valve closure. The sealing element is pressed against the trigger opening by a resetting element, creating a controlled flow path that amplifies the actuating effect. This intermediary mechanism allows a smaller actuating force to control a larger valve cross-section, resolving the contradiction between high flow rate requirements and limited actuating force from the SMA actuator.
2Force
If the SMA actuator is dimensioned to provide high actuating forces, then the force output is improved, but the space requirements and costs increase
Solution Approach 1:
The trigger opening mechanism acts as a force amplifier, allowing a compact SMA actuator with limited force output to effectively control a large valve. The sealing element pressed against the trigger opening creates a mechanical advantage that multiplies the small actuating force into sufficient force for closing the main valve, eliminating the need for an oversized actuator.
Solution Approach 2:
The patent utilizes pneumatic pressure differentials across the membrane to assist in valve actuation. The pressure difference between the first and second regions of the valve chamber works together with the SMA actuator, reducing the mechanical force burden on the actuator itself and allowing for a more compact design.
3Force
If pilot control valves are used to control greater pressure or volumetric flow rate with little actuating effort, then the actuating force is reduced, but the device complexity increases
Solution Approach 1:
The patent integrates the trigger opening control mechanism directly into the main valve structure, combining what would traditionally be separate pilot control and main valve functions into a single unified design. The sealing element and resetting element are incorporated into the existing valve body, eliminating the need for additional separate pilot valves and reducing overall system complexity while maintaining the force reduction benefit.
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 design achieves high volumetric flow rates with reduced actuating force on the SMA actuator, minimizing installation space and costs, while maintaining efficient operation across varying pressures.
Implementation Method 1
shape memory wire (SMA=shape memory alloy) is increasingly being used, which shortens in length in the event of current flow and the resulting heating
Implementation Method 2
shape memory wire (SMA=shape memory alloy) is increasingly being used, which shortens in length in the event of current flow and the resulting heating
Implementation Method 3
utilizing the pressure difference across a membrane to minimize the force required for actuation
Data Source
AI summary
A pneumatic valve includes a fluid supply port, a fluid outlet port, and a fluid drainage opening. A valve chamber includes a fluid supply opening connected to the fluid supply port, a fluid outlet opening connected to the fluid outlet port, a trigger opening connected to an actuator chamber having the fluid drainage opening. An actuator disposed in the actuator chamber is formed with an SMA wire includes an actuating element and a resetting element. A sealing element is arranged on the actuating element and is pressed against the trigger opening by the resetting element in a non-actuated state and opens up the trigger opening in an actuated state. A membrane divides the valve chamber into two a first region connected to the trigger opening and a second region connected to the fluid supply opening.