Fluid Control Device Thermal Expansion Matching

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Solution Overview

Problem

Conventional fluid pumps face challenges in miniaturization while maintaining performance, as their pressure-flow rate characteristics are affected by temperature changes due to differences in coefficients of linear expansion of materials used in their components.

Innovation Solution

A fluid control device is designed with a vibrating plate unit, driver, and base plate, where the materials' coefficients of linear expansion are carefully matched to ensure that both the vibrating plate and flexible plate bend equally with temperature changes, maintaining a constant distance and thus stabilizing pressure-flow rate characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the fluid pump is miniaturized to reduce device size, then the device size is reduced, but the pump performance (discharge flow rate and discharge pressure) decreases

Engineering Contradiction:

Improvedevice sizeVSAvoidpump performance

Core Design Contradiction:

Volume of moving objectVSProductivity

Solution Approach 1:

The flexible plate is designed to vibrate dynamically in response to actuator operation, creating pressure fluctuations that enhance fluid pumping efficiency. The vibration frequency and amplitude are optimized to maintain high pump performance despite the miniaturized device size.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent optimizes material parameters by selecting materials with matched coefficients of linear expansion for the flexible plate and base plate. This parameter matching prevents thermal deformation that would otherwise reduce pumping efficiency in miniaturized devices.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If different materials are used for base plate and flexible plate to achieve functional requirements, then material properties are optimized, but temperature-induced deformation occurs due to different coefficients of linear expansion

Engineering Contradiction:

Improvematerial selection flexibilityVSAvoiddistance between flexible plate and base plate

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent explicitly addresses thermal expansion by selecting materials for the base plate and flexible plate with matched coefficients of linear expansion. This ensures that both components expand or contract equally with temperature changes, maintaining a constant distance between them and preventing deformation that would affect pump performance.

Inventive Principle:

Principle #37Thermal expansion

3Length of stationary object

If the flexible plate is made thinner to reduce device thickness, then the device becomes thinner, but the structural strength and stability decrease

Engineering Contradiction:

Improvedevice thicknessVSAvoidflexible plate strength

Core Design Contradiction:

Length of stationary objectVSStrength

Solution Approach 1:

The patent employs a thin flexible plate that vibrates to pump fluid, utilizing the flexibility of thin films to achieve pumping action. The thin plate is designed with appropriate material properties and boundary conditions to maintain sufficient structural strength while enabling the desired vibration and fluid pumping function.

Inventive Principle:

Principle #30Flexible shells and thin films

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

This configuration significantly reduces and prevents variations in pressure-flow rate characteristics caused by temperature changes, allowing for a high discharge pressure and large discharge flow rate despite the small size and low profile design of the fluid pump.

Implementation Method 1

a piezoelectric element 32 attached to an upper surface of the vibrating plate 141; When a driving voltage is applied to the piezoelectric element 32, the vibrating plate 141 bends and vibrates as a result of the expansion and contraction of the piezoelectric element 32.

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the coefficient of linear expansion of the material of the base plate 191 and the coefficient of linear expansion of the material of the frame plate 161 substantially equal a coefficient of linear expansion of the material of either the vibrating plate 141 or the piezoelectric element 142, whichever is closer to the flexible plate 151, and a coefficient of linear expansion of the material of either the vibrating plate 141 or the piezoelectric element 142, whichever is farther from the flexible plate 151

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9028226B2Fluid control device

Publication Date: 2015.05.12 MURATA MFG CO LTD

AI summary

A fluid control device includes a vibrating plate unit, a driver, a flexible plate, and a base plate. The vibrating plate unit includes a vibrating plate including first and second main surfaces, and a frame plate surrounding the surrounding of the vibrating plate. The driver is bonded to the first or the second main surface of the vibrating plate and vibrates the vibrating plate. The flexible plate includes a hole provided therein, and is bonded to the frame plate so as to face the vibrating plate. The base plate is bonded to the main surface of the flexible plate on a side opposite to the vibrating plate. A size relationship between the coefficients of linear expansion of the material of the base plate and the frame plate is equal to a size relationship between the coefficients of linear expansion of the material of the vibrating plate and the driver.