One-Piece Pleated Shell for Hour-Glass Transducer Waterproofing

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Solution Overview

Problem

Hour-glass transducers require multi-piece shells, which are complex and unreliable due to the need for an elastomeric boot for waterproofing, leading to high wear and reduced reliability.

Innovation Solution

A one-piece composite shell with pleated geometry and anisotropic material properties, providing high axial stiffness and low circumferential stiffness, enabling efficient velocity transformation and automatic waterproof integrity without a boot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multi-piece shells are used to construct hour-glass transducers, then the structural flexibility and assembly feasibility are improved, but the reliability deteriorates due to the need for elastomeric boots for waterproofing which are subject to high wear rates

Engineering Contradiction:
Improveassembly feasibilityVSAvoidwaterproofing reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent merges multiple shell pieces into a single integrated one-piece shell structure. This eliminates the interfaces between multiple pieces that required elastomeric boots for waterproofing, thereby resolving the contradiction by maintaining assembly feasibility while dramatically improving waterproofing reliability through structural integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The one-piece shell is designed with integrated pleated geometry that segments the structural functions into different geometric zones rather than requiring separate physical components. This allows the shell to achieve both structural flexibility and waterproof integrity through geometric design rather than component assembly.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If multi-piece shells with elastomeric boots are used, then assembly is feasible, but the device complexity increases due to the additional boot component and assembly steps

Engineering Contradiction:
Improveassembly feasibilityVSAvoidshell structure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The elastomeric boot and shell pieces are merged into a single integrated one-piece shell structure. This eliminates the need for separate boot components and reduces assembly steps while maintaining the necessary structural flexibility, thereby reducing device complexity without sacrificing assembly feasibility.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The one-piece shell performs multiple functions simultaneously: it provides structural support, waterproofing, and flexible deformation capabilities that were previously distributed across multiple components. This multi-functionality reduces the overall device complexity while maintaining assembly feasibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If a one-piece shell is used to eliminate the boot and simplify assembly, then reliability and ease of manufacture are improved, but achieving the required axial compliance and radial-to-axial transformation becomes more difficult

Engineering Contradiction:
Improvewaterproofing reliabilityVSAvoidgeometric design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs pleated geometry with specific curvatures and radii of curvature in the one-piece shell design. These curved geometric features enable the shell to achieve the required axial compliance and radial-to-axial transformation ratios through its shape alone, resolving the contradiction by embedding the compliance functionality directly into the geometric design of the simplified one-piece structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent optimizes specific geometric parameters of the one-piece shell including pleat dimensions, curvature radii, and wall thickness distribution. By carefully controlling these parameters, the design achieves the required mechanical compliance and transformation ratios while maintaining the simplicity and reliability of the one-piece construction, thereby reducing geometric design complexity through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

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 simplifies assembly, ensures watertight integrity, and achieves highly efficient velocity profiles, enhancing the reliability and acoustic performance of hour-glass transducers.

Implementation Method 1

fibers of the composite material are oriented in a manner such that the shell has an approximately 10:1 ratio of stiffness in an axial direction compared to a circumferential direction

Methodology Applied
Scientific EffectAnisotropy: Anisotropy

Implementation Method 2

the shell is made of a composite material

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 3

a pleated geometry between the first shell end and the second shell end

Methodology Applied
Scientific EffectCorrugation: Corrugation

Data Source

PatentEP3948843B1Enhanced hour-glass transducer
Publication Date: 2024.08.14 RAYTHEON CO
  • EP3948843B1 patent drawingFigure 1~2
  • EP3948843B1 patent drawingFigure 3A~3B
  • EP3948843B1 patent drawingFigure 4A~4B

AI summary

An hourglass transducer (100) including a longitudinal driver (105), a shell (110, 200, 300, 301), and a pair of endcaps (115) is provided. The driver drives the transducer. The pair of endcaps is attached to ends of the driver and cap the shell enclosing the transducer. The shell includes a first shell end (210), a second shell end (210), and a pleated geometry (205). The first shell end and second shell end are structured with circular cross sections. The pleated geometry is between the first shell end and the second shell end. A perimeter of the pleated geometry is the same as perimeters of the circular cross sections of the first shell end and the second shell end.