Gradient Plasticizer Sealing Body for Gas Sensor Housing

Solution Overview

Problem

Conventional sensors for measuring gas properties, such as oxygen content in exhaust gases, face challenges with high plasticizer content leading to increased elasticity and initial sealing capability but resulting in material discharge and embrittlement, causing leakage paths, while low plasticizer content improves aging behavior but compromises processability and sealing performance.

Innovation Solution

A sensor design with a sealing body having a gradient of plasticizer concentration, where the outer sections have a higher proportion of plasticizers for high elasticity and the inner sections have a lower proportion for stability, using fluororubber or perfluororubber with a fluorine content of at least 60% by weight, and incorporating plasticizers like dioctylphthalate to maintain sealing integrity and resist thermal aging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high proportion of plasticizers is added to the elastomeric mass, then elasticity and sealing capability are improved, but material discharge during thermal aging increases leading to shrinkage and embrittlement

Engineering Contradiction:

Improvesealing capabilityVSAvoidmaterial stability during thermal aging

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The sealing body is designed with non-uniform plasticizer distribution, where the outer region contains a higher proportion of plasticizers for enhanced sealing capability, while the inner region contains a lower proportion to maintain structural stability during thermal aging. This local differentiation resolves the contradiction between initial sealing performance and long-term material stability.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If a lower proportion of plasticizers is added to the elastomeric mass, then aging behavior is improved, but processability and sealing capability deteriorate

Engineering Contradiction:

Improveaging behaviorVSAvoidprocessability

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The sealing body is designed with non-uniform plasticizer distribution, where the outer region contains a higher proportion of plasticizers for enhanced sealing capability, while the inner region contains a lower proportion to maintain structural stability during thermal aging. This local differentiation resolves the contradiction between initial sealing performance and long-term material stability.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If a high proportion of plasticizers is added to the elastomeric mass, then processability is improved, but material discharge during thermal aging increases causing leakage paths

Engineering Contradiction:

ImproveprocessabilityVSAvoidtightness against leakage

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The sealing body is designed with non-uniform plasticizer distribution, where the outer region contains a higher proportion of plasticizers for enhanced sealing capability, while the inner region contains a lower proportion to maintain structural stability during thermal aging. This local differentiation resolves the contradiction between initial sealing performance and long-term material stability.

Inventive Principle:

Principle #3Local quality

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 sensor achieves a balance between high initial sealing capability and long-term stability by maintaining material integrity and preventing leakage, ensuring reliable gas and water tightness even under thermal stress.

Implementation Method 1

The first section has a higher deformability than the second section... the first section having a higher proportion of plasticizer than the second section

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9618492B2Sensor having a housing seal made of synthetic rubbers having differing elasticity

Publication Date: 2017.04.11 ROBERT BOSCH GMBH

AI summary

A sensor for determining at least one property of a measuring gas in a measuring gas space is provided. The sensor has a housing which includes a housing opening. At least one connection cable is led from the housing through the housing opening. The sensor further includes at least one sealing body, in particular a grommet, the sealing body at least partially enclosing the connection cable. The sealing body has at least one first section and at least one second section, the first section having a higher deformability than the second section.