SMA Valve Pivoting Link for Low Friction Seat Air Control

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Solution Overview

Problem

SMA valves for vehicle seat air cell pressurization systems face challenges in achieving low friction and compact design due to the need for guiding elements that introduce friction and result in larger lateral dimensions.

Innovation Solution

A SMA valve design featuring a valve element suspended by a connecting link with a hinge, allowing pivotal movement between closed and open positions without additional guiding elements, and an SMA wire orientation that increases the transmission ratio for more uniform movement, reducing lateral dimensions and friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If guiding elements are used to guide the valve element movement, then the valve element movement is constrained and controlled, but friction increases and lateral dimensions increase

Engineering Contradiction:

Improvevalve element movement controlVSAvoidfriction

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent removes traditional guiding elements (such as guide pins or guide slots) from the valve structure. Instead, the valve element is suspended by a connecting link that pivots about a fixed point, allowing the valve element to move freely between open and closed positions without contact with guiding surfaces, thereby eliminating friction from guiding mechanisms.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than using guiding elements to constrain the valve element movement, the patent inverts the approach by using a pivoting connecting link that naturally defines the movement path through its rotation about a fixed pivot point. The valve element moves in response to forces applied to the connecting link without requiring external guidance.

Inventive Principle:

Principle #13The other way round (Inversion)

2Device complexity

If traditional valve designs are used, then the valve structure is simple, but lateral dimensions are large

Engineering Contradiction:

Improvevalve structure simplicityVSAvoidlateral dimensions

Core Design Contradiction:

Device complexityVSArea of stationary object

Solution Approach 1:

The patent repositions the valve element movement from a lateral direction to a direction more aligned with the flow axis. The connecting link pivots about a fixed point, allowing the valve element to move primarily in the flow direction rather than laterally, thereby reducing the lateral footprint of the valve while maintaining functional simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If SMA wire is oriented at small angle to valve element longitudinal direction, then transmission ratio increases and movement uniformity improves, but lateral dimensions increase

Engineering Contradiction:

Improvetransmission efficiencyVSAvoidlateral dimensions

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The patent employs an asymmetric arrangement where the SMA wire is attached to the valve element at an optimized angle that balances transmission efficiency and compactness. The connecting link pivots about a fixed point, creating an asymmetric mechanism that achieves high transmission ratio without requiring the SMA wire to be oriented at a small angle to the valve element longitudinal direction, thus maintaining compact lateral dimensions.

Inventive Principle:

Principle #4Asymmetry

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 a compact, low-friction, and stable SMA valve operation with improved transmission efficiency, enabling efficient control of air cell inflation and deflation in vehicle seats.

Implementation Method 1

a SMA wire extending between a part fixed in the housing and the valve element and arranged such that shortening of the SMA wire upon exceeding its threshold temperature exerts a force on the valve element which pulls the valve element away from the closed position

Methodology Applied

Scientific EffectShape memory alloy effect: Shape Memory Alloy

Implementation Method 2

a spring element adapted to exert a bias force on the valve element urging it to the closed position

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10207619B2SMA valve for controlling pressurized air supply to an air cell in a vehicle seat

Publication Date: 2019.02.19 LEAR CORP

AI summary

The present invention provides a SMA valve for controlling pressurized air supply to an air cell in a vehicle seat comprising: a valve housing, a valve element (4) which is moveably suspended in the housing to be moveable between a closed position and an open position, a spring element adapted to exert a bias force on the valve element urging it to the closed position, and a SMA wire (1) extending between a part fixed in the housing and the valve element and arranged such that shortening of the SMA wire upon exceeding its threshold temperature exerts a force on the valve element which pulls the valve element away from the closed position against the bias force of the spring element, characterized in that the valve element (4) is suspended by a connecting link (10, 10′) connected with one of its ends to the valve element (4) and with its opposite end to a stationary component (8) in the housing by a hinge (12, 12′) enabling pivotal movement of the connecting link (10, 10′) between a first and second position of the connecting link corresponding to the closed and open position of the valve element (4), respectively.