Piezoelectric Valve Support Thickness Optimization
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Solution Overview
Problem
Piezoelectric valves face limitations in switching capacity due to the characteristic force-displacement curve, where the closing force decreases with increasing deflection, restricting the fluid power that can be switched.
Innovation Solution
The thickness of the elastically flexible support of the piezoelectric bending element is limited to at most 0.25 mm, with a surface quality of up to 16 μm Rz and a hardness of 50-90 Shore A, minimizing the deflection required for leak-free closure and increasing the effective working stroke and closing force, while additional stops optimize sealing and reduce adhesion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the bending element deflects further to close the nozzle, then the valve can switch higher fluid power, but the closing force decreases due to the characteristic force-displacement curve
Solution Approach 1:
The patent changes the physical parameters of the support structure by reducing its thickness to at most 0.25 mm (preferably at most 0.2 mm) and controlling its hardness to 50-90 Shore A. This parameter optimization allows the support to compress efficiently during closing, enabling the bending element to achieve higher deflection while maintaining sufficient closing force, thereby resolving the contradiction between switching capacity and closing force.
Solution Approach 2:
The support is designed with non-uniform thickness, being thinnest (at most 0.25 mm) in the area opposite the nozzle where closing force is needed, while being thicker in other areas for structural support. This local quality variation allows the bending element to deflect further without compromising overall structural integrity, enabling higher switching capacity while maintaining closing force.
2Reliability
If the support is made thinner to improve sealing, then the closing force increases, but the support may become structurally insufficient
Solution Approach 1:
The support is made from elastomeric material with specifically controlled properties (hardness 50-90 Shore A) that combine flexibility for sealing with sufficient structural strength. This material selection creates a composite structure that is thin enough (at most 0.25 mm) to provide excellent sealing behavior while remaining structurally sufficient to support the bending element.
Solution Approach 2:
The support has varying thickness throughout its structure - thinnest (at most 0.25 mm) in the critical sealing area opposite the nozzle, and thicker in other regions for structural support. This local quality variation resolves the contradiction by providing thin support where sealing is needed while maintaining structural strength where required.
3Productivity
If the bending element has larger working stroke for unimpeded flow, then the valve opens more fully, but the closing force is reduced due to the force-displacement characteristic
Solution Approach 1:
By optimizing the support thickness to at most 0.25 mm and hardness to 50-90 Shore A, the patent enables the bending element to achieve larger deflection (working stroke) while maintaining adequate closing force. The optimized support parameters allow the bending element to lift further from the nozzle for unimpeded flow while the support compresses efficiently during closing to maintain sufficient contact force.
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 design enhances switching capacity and reliability by reducing the inefficient idle stroke of the bending element, allowing for unimpeded flow and improved sealing at higher pressures, and minimizes adhesion and flow-dynamic impairments.
Implementation Method 1
a piezoelectric bending element that can be deformed by electrical loading being accommodated in the interior of the housing in such a way that the nozzle can be closed by a section of the flexible element that can be moved relative to the nozzle due to the deformation of the flexible element
Implementation Method 2
the flexible element has a support made of an elastically resilient material at least in its region opposite the nozzle
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The piezoelectric valve has a housing (1), which has an interior (2) which is mapped to a connection. The annular sealing surface (28) is adjacent to an area (29, 32) which is opposite of the adjacent surface. The deformation of a second sealing structure (27) is limited in the area of sealing surface (28).