Gas Sensor Tube Fixation via Integrated Grip Member

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Solution Overview

Problem

Existing gas sensors face issues with the tube being insufficiently fixed, leading to exposure of lead wires and potential water ingress due to the clamp member's inadequate fixation.

Innovation Solution

A gas sensor design featuring a cylindrical body with a swaged elastic body and a grip member that covers the tube, ensuring it protrudes beyond the open end, providing a secure fixation and sealing against water entry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the clamp member clamps the cover member and outer cylinder, then the assembly is secured, but the tube becomes insufficiently fixed and may come off

Engineering Contradiction:
Improvetube fixation reliabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The grip member integrates multiple functions: it grips the tube, grips the outer cylinder, and works with the cover member as a unified assembly. This merging of functions into a single component eliminates the need for separate tube fixation mechanisms while maintaining reliable securing of all elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The grip member is designed as a multi-functional component that simultaneously performs tube gripping, outer cylinder gripping, and contributes to cover member securing. This universal component replaces what would traditionally require multiple specialized parts, simplifying the overall device structure.

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

2Object-affected harmful factors

If the tube is not securely fixed, then the structure is simpler, but the lead wires are exposed and water can enter the sensor

Engineering Contradiction:
Improvewater ingress preventionVSAvoidtube fixation structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The tube fixation function is merged into the grip member assembly, which also secures the outer cylinder and works with the cover member. This integrated approach provides comprehensive protection against water ingress through a unified structure rather than separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The grip member acts as an intermediary component that mediates between the tube, outer cylinder, and cover member, creating a coordinated assembly that collectively prevents water ingress while maintaining structural simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the tube protrudes from the grip member, then the tube is more securely fixed, but the grip member must be precisely positioned

Engineering Contradiction:
Improvetube fixation securityVSAvoidgrip member positioning accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The grip member is pre-configured with gripping surfaces and structural features that automatically position the tube correctly during assembly. The protruding portion of the tube is designed to engage with corresponding features in the grip member, ensuring proper positioning is achieved as a preliminary step in the assembly process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The assembly structure is designed so that the tube, grip member, and outer cylinder self-position and self-align during assembly. The protruding tube portion naturally engages with the grip member's gripping surface, and the entire assembly self-secures without requiring external positioning tools or complex alignment procedures.

Inventive Principle:
Principle #25Self-service

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 reliably fixes the tube and prevents water ingress, enhancing the sensor's durability and performance by ensuring the tube remains securely attached.

Implementation Method 1

an elastic body through which the lead wire penetrates, the elastic body being disposed within the cylindrical body to seal inside of the cylindrical body from an outside of the open end

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the cylindrical body has a diameter-reduced portion that swages the elastic body from a periphery

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3795989B1Gas sensor
Publication Date: 2023.06.07 NGK INSULATORS LTD
  • EP3795989B1 patent drawingFigure 1
  • EP3795989B1 patent drawingFigure 2~3
  • EP3795989B1 patent drawingFigure 4~5

AI summary

In a gas sensor, not only a tube 70 covers lead wires 48, but also the tube 70 covers an outer peripheral surface of an end portion of an outer cylinder 46 including an open end 46a. A portion of the outer peripheral surface of the outer cylinder 46 covered with the tube 70 is gripped by a clamp 80. Thus, the clamp 80 integrally grips the tube 70 and the outer cylinder 46. Moreover, the tube 70 protrudes from the clamp 80 to a side of the outer cylinder 46 opposite from the open end 46a (protrusion amount L > 0). Further, the open end 46a of the outer cylinder 46 forms a large-diameter portion whose outer diameter is larger than an inner diameter D1 of the clamp 80.