Miniature Vector Sensor Cantilever Piezoelectric Transducers
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Solution Overview
Problem
Miniaturization of vector sensors for underwater acoustic devices poses challenges in physical arrangement of sensor components, control of resonance effects, and reducing sensor density while maintaining directivity information.
Innovation Solution
A miniature vector sensor design featuring a cylindrical bulkhead partition with longitudinal channels, cantilever piezoelectric transducing pieces enclosed in pressure housing capsules, and foam end pieces for wiring and strength member passage, allowing for a linear array configuration that minimizes size and maximizes directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If vector sensor components are miniaturized, then the sensor size is reduced, but the physical arrangement of components becomes more difficult and resonance effects increase
Solution Approach 1:
The patent merges the piezoelectric crystal and the diaphragm into a single integrated unit. The piezoelectric crystal is affixed directly to the rear surface of the diaphragm, eliminating the need for separate mounting structures and reducing the number of discrete components. This integration simplifies the physical arrangement while maintaining miniaturization benefits.
Solution Approach 2:
The patent employs a nested structure where the piezoelectric crystal is positioned within the sealed cavity formed by the diaphragm and the housing. The electrical leads are routed through the housing wall, nesting the wiring path within the overall sensor structure. This nesting approach maximizes space utilization and simplifies component arrangement in the miniaturized sensor.
2Volume of moving object
If vector sensor components are miniaturized, then the sensor size is reduced, but resonance effects become more difficult to control
Solution Approach 1:
The patent applies preliminary anti-action by using the sealed cavity and damping material to preemptively counteract resonance effects before they can develop. The cavity is sealed to prevent acoustic feedback that could amplify resonance, and damping material is incorporated to actively suppress resonant vibrations of the diaphragm and crystal assembly. This preliminary countermeasures approach controls resonance in the miniaturized structure.
Solution Approach 2:
The patent introduces damping material as an intermediary between the piezoelectric crystal assembly and the housing. This damping material acts as a mediator that absorbs and dissipates resonant energy, preventing it from propagating through the miniaturized structure. The intermediary damping layer effectively controls resonance effects while maintaining the compact sensor design.
3Volume of moving object
If vector sensor components are miniaturized, then the sensor size is reduced, but the sensor density increases
Solution Approach 1:
The patent applies local quality by using a lightweight housing material with specific acoustic properties in the sensor housing. The housing is designed with local variations in density and acoustic impedance to optimize acoustic transmission while maintaining overall low density. The diaphragm material is also selected for its specific acoustic properties, creating local quality variations that reduce overall sensor density despite miniaturization.
Solution Approach 2:
The patent employs composite materials in the construction of the sensor components. The housing may use composite materials that combine lightweight properties with acoustic transparency. The diaphragm and housing assembly utilizes materials with different acoustic impedances to reduce overall density while maintaining acoustic sensitivity. This composite material approach allows miniaturization without proportionally increasing sensor density.
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 efficient miniaturization while maintaining directivity and reducing resonance, enabling effective underwater acoustic measurements in a compact and robust form.
Implementation Method 1
a first cylindrical piezoelectric transducing piece affixed to the first surface of the bulkhead partition and a second cylindrical piezoelectric transducing piece affixed to the second surface
Data Source
AI summary
A vector sensor for use in acoustic instruments is described. The vector sensor includes: a cylindrical bulkhead partition defining a plurality of channels extending longitudinally on a circumferential wall of the bulkhead partition between a first surface and a second surface of the bulkhead partition; first and second cylindrical piezoelectric transducing pieces affixed to the bulkhead partition and extending outwardly as cantilever beams and contained within respective pressure housing capsules. The sensor may include cylindrical foam end pieces fitted over the capsules and having corresponding channels in their outer surfaces that correspond to channels in the bulkhead partition, so as to allow wiring and strength members to pass through. The cylindrical piezoelectric transducing pieces may be formed from a piezoelectric cylindrical tube with a first electrode covering its inner surface and a second electrode on its outer surface. The second electrode may be formed from a plurality of electrically disconnected electrodes spaced around the tube and located towards a fixed end of the tube, leaving a portion of the outer surface near the free end of the tube uncovered.