Gas Sensor Connector Protrusions Reduce Grommet Heat Transfer

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Solution Overview

Problem

Existing gas sensors face issues with grommet temperature increase due to heat transfer from the connector, leading to rapid deterioration, and existing solutions either increase sensor size or raise costs by using heat-resistant grommets.

Innovation Solution

A gas sensor design with a connector featuring protruding portions that reduce the contact area with the grommet, minimizing heat transfer and ensuring strength, while maintaining a compact size and low costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire rear end face of the connector is in contact with the grommet to ensure positioning and structural stability, then the connector-grommet connection is stable, but heat transfer from the connector to the grommet increases, causing rapid grommet deterioration

Engineering Contradiction:

Improveconnector-grommet connection stabilityVSAvoidgrommet temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The rear end face of the connector is divided into multiple contact regions separated by protruding portions. This segmentation reduces the continuous contact area between the connector and grommet, thereby decreasing heat transfer while maintaining positioning stability through distributed contact points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connector surface is designed with localized protruding portions that create specific contact regions with the grommet. This local quality modification ensures that heat transfer occurs only at discrete points rather than across the entire surface, reducing overall thermal coupling while maintaining mechanical connection.

Inventive Principle:

Principle #3Local quality

2Temperature

If the distance between the heat source (connector) and the grommet is increased to reduce heat transfer, then the grommet temperature decreases, but the overall size of the gas sensor increases

Engineering Contradiction:

Improvegrommet temperatureVSAvoidgas sensor length

Core Design Contradiction:

TemperatureVSLength of moving object

Solution Approach 1:

Instead of increasing the axial distance between the connector and grommet, the solution introduces a radial dimension feature (protruding portions) on the connector surface. This dimensional approach reduces heat transfer contact area without affecting the overall length of the sensor assembly.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If a heat-resistant grommet is used to withstand high temperatures, then the grommet deterioration is suppressed, but the cost of parts increases

Engineering Contradiction:

Improvegrommet heat resistanceVSAvoidparts cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The design converts the harmful effect of heat transfer into a beneficial geometric feature. The protruding portions, which could be seen as adding complexity, actually reduce heat transfer contact area and eliminate the need for expensive heat-resistant grommet materials, using simple geometry to achieve thermal management.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Temperature

If the contact area between the connector and grommet is reduced to suppress heat transfer, then the grommet temperature decreases, but the positioning stability during production may be compromised

Engineering Contradiction:

Improvegrommet temperatureVSAvoidgrommet positioning accuracy

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The contact interface is segmented into multiple discrete regions through protruding portions. This segmentation maintains positioning stability by providing multiple contact points that distribute mechanical loads, while simultaneously reducing the total contact area to minimize heat transfer.

Inventive Principle:

Principle #1Segmentation

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 effectively suppresses grommet temperature increase, prolonging the sensor's lifespan and maintaining a compact, cost-effective structure.

Implementation Method 1

If heat is likely to be transferred from the connector to the grommet, the temperature of the grommet becomes high... the contact area between the connector and the grommet is smaller... thus it is possible to suppress heat transfer from the connector to the grommet

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS11852606B2Gas sensor for suppressing an increase in the temperature of a grommet while suppressing an increase in the size cost of gas sensor parts

Publication Date: 2023.12.26 NGK INSULATORS LTD

AI summary

The gas sensor includes a sensor element, an element sealing member, a lead wire, a connector, an outer tube, and a grommet. The sensor element has, in the vicinity of a rear end thereof, a surface on which an electrode pad is formed. The element sealing member is configured to hold part of the sensor element. The connector is configured to hold the portion of the sensor element in which the electrode pad is formed, and to electrically connect the electrode pad and the lead wire. The outer tube is configured to be fixed to the element sealing member, and to surround the connector. The grommet is configured to be attached to a rear end of the outer tube, and to allow the lead wire to extend therethrough. A protruding portion is formed on a rear end face of the connector and is in contact with the grommet.