Shape Memory Alloy Valve Stack for Lightweight Fluid Control
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Solution Overview
Problem
Existing pneumatic valves in vehicle seat systems are heavy, energy-intensive, and noisy, and conventional solutions with duplicate designs on carriers require a large number of parts, leading to increased weight and complexity.
Innovation Solution
A 3/3-way valve design utilizing shape memory alloy wires to actuate valve elements, where two wires made of shape memory alloy are used to move actuating elements within a housing, reducing the number of components and weight while allowing for reliable fluid control with minimal parts, enabling simultaneous or separate actuation of valve stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodynamic systems with lifting magnets or solenoid motors are used to control air flow, then the valves can reliably actuate the valve elements, but the weight, energy consumption, and acoustic emissions increase significantly
Solution Approach 1:
The patent replaces electrodynamic actuators (lifting magnets, solenoid motors) with a purely mechanical actuation system using shape memory alloy wires. These wires undergo reversible structural transformation when heated above a certain temperature, changing from martensitic to austenitic structure, which causes them to shorten and directly actuate the valve element mechanically, eliminating the need for heavy electromagnetic components
Solution Approach 2:
The invention changes the physical state of the shape memory alloy wires by varying temperature. When heated above the transformation temperature (around 80°C), the wires transition from martensitic to austenitic structure, causing length changes that drive the valve actuation. This parameter-based control replaces the need for complex electromagnetic control systems
2Adaptability or versatility
If duplicate valve stages are applied on a carrier as disclosed in DE 10 2005 060 217 B4, then the valve can control multiple fluid paths, but the number of parts and overall weight increase
Solution Approach 1:
The patent combines two valve stages into a single integrated unit with a common carrier. Instead of duplicating complete valve assemblies, the invention merges the actuating elements and sealing components onto one carrier structure, reducing the total number of parts while maintaining the ability to control multiple fluid paths independently
Solution Approach 2:
The common carrier serves multiple functions: it supports both actuating elements, provides sealing surfaces for both valve stages, and integrates the fluid pathways. This multi-functional design eliminates redundant components and reduces overall device complexity while preserving versatile fluid control capabilities
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 achieves a compact, lightweight, and efficient valve design that can control fluid flow with reduced components, allowing for precise and reproducible movement of actuating elements, and enables the mixing of fluids by opening or closing ports simultaneously, thus addressing the issues of weight, energy consumption, and part count in existing systems.
Implementation Method 1
If these materials are heated above a certain temperature, they undergo a reversible structural transformation, which is accompanied by changes in properties and external geometry (e.g. length). More precisely, these are alloys that occur in two different structural states depending on their temperature. At room temperature there is a martensitic structure, which transforms into an austenitic structure in the case of a face-centered cubic lattice at a certain limit temperature, around 80° C.
Implementation Method 2
these materials are heated above a certain temperature, they undergo a reversible structural transformation
Implementation Method 3
A return element is arranged between the first actuating element and the second actuating element. The return element exerts a force that keeps the first actuating element and the second actuating element in a rest position
Data Source
AI summary
A valve housing (1) has first and third openings (1.1, 1.3), and first and second actuating elements (6.1, 6.2) that are movable along a longitudinal axis of the housing (1). A return element (5) is between the actuating elements (6.1, 6.2), and exerts a force to keep the actuating elements (6.1, 6.2) in a rest position to close or open the first and third openings (1.1. 1.3). First and second wires (4.1, 4.2) are formed from a shape memory alloy. The first wire (4.1) is on the first actuating element (6.1) and the second wire (4.2) is on the second actuating element (6.2). An electric current to the first or second wire (4.1, 4.2) contracts the respective wire (4.1, 4.2) and moves the corresponding actuating element (6.1, 6.2) into an activated position against the force exerted by the return element (5).