Fluid Duct Bead Geometry for Secure Boot Clamping

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Solution Overview

Problem

Existing fluid ducts with beads on their outer periphery face issues with secure clamping due to boot slippage when pressurized, leading to unreliable connections.

Innovation Solution

The fluid duct design incorporates specific radii and distances in the bead geometry, including radii R1, R2, R3, and R4, and distances d1, d2, to create a smooth corner and flat surface for the elastomeric boot, preventing slippage and ensuring a secure connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bead is added to the outer periphery of the duct to position the clamp, then the clamp positioning is improved, but the boot slippage occurs when pressurized leading to unreliable connections

Engineering Contradiction:
Improveconnection reliabilityVSAvoidboot slippage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The bead geometry is optimized with specific radii (R1, R2, R3, R4) and distances (d1, d2) to create different local characteristics: a smooth corner region for the boot to slide over and a flat surface region to prevent slippage. This local differentiation of geometric properties prevents boot slippage while maintaining clamp positioning functionality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bead incorporates specific curved surfaces with defined radii (R1 for the forward face, R2 for the rear face, R3 and R4 for corner radii) that create a smooth transition for the boot while providing a flat anchoring surface. The curvature design allows the boot to properly engage and prevents slippage under pressure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If the bead geometry is simplified for ease of manufacture, then the manufacturing process is easier, but the boot slippage prevention is compromised

Engineering Contradiction:
Improvebead manufacturingVSAvoidconnection security
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Specific geometric parameters (radii R1-R4 and distances d1-d2) are defined with optimal ranges to achieve both manufacturability and functional performance. The radius ratios (R1/R2 between 2.1-4.8, d1/d2 between 0.200-0.270) provide a balanced design that can be manufactured using standard processes while ensuring reliable boot engagement and slippage prevention.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2740984B1Fluid duct with improved connecting bead
Publication Date: 2019.10.30 HAMILTON SUNDSTRAND CORP
  • EP2740984B1 patent drawingFigure 1~2

AI summary

A fluid duct (22) has a plastic body (27) with a forward cylindrical portion (117) having an outer periphery and a rear cylindrical portion (118) having an outer periphery. The forward and rear cylindrical portions (117, 118) are at equal radial distances from a center line of the duct. A bead (28) is formed on an outer periphery of the duct body (27) intermediate the forward and rear cylindrical portions (117, 118). The bead (28) has a radially outermost first distance (d1) measured perpendicularly away from the outer periphery of the forward cylindrical portion (117). A second distance (d2) is defined between a forward end (29) of the duct body (27) to a rearmost end of the bead (28). The ratio of the first distance (d1) to the second distance (d2) is between .200 and .270.