Gas Sensor Polymer Base Metal Tube Connection
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Solution Overview
Problem
Existing gas sensors face challenges in reducing size and preventing thermal degradation due to complex metal shell structures and direct heat transfer, which complicates manufacturing and increases component count and cost.
Innovation Solution
A gas sensor design featuring a polymer base attached to a metal shell via a metal tube, allowing for easy integration through insert molding, reducing the number of components, and maintaining airtightness with a sealing member, while minimizing heat transfer and size increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a resin base is attached to a metal shell using a crimping portion and flange structure, then the base can be securely fixed to the metal shell, but the metal shell diameter increases and the overall gas sensor size cannot be reduced
Solution Approach 1:
The invention introduces a separate connection component (connection member with positioning protrusion and engagement groove) that divides the fixing function from the metal shell structure. This allows the metal shell to maintain a simple cylindrical shape while the connection member handles the attachment task, thus reducing overall device complexity without compromising fixation security.
Solution Approach 2:
The connection member acts as an intermediary between the metal shell and the resin base. It includes a positioning protrusion that fits into a groove on the metal shell and an engagement groove that receives the resin base, thereby mediating the connection between these two components. This intermediary approach simplifies both the metal shell and base structures while ensuring secure attachment.
2Reliability
If the base is directly in contact with the metal shell, then the structure is simple and manufacturing is easy, but heat from the metal shell directly transfers to the base causing thermal degradation
Solution Approach 1:
The connection member serves as a thermal barrier and intermediary between the metal shell and the resin base. It includes an insulating portion made of resin material that prevents direct thermal contact while maintaining mechanical connection. This intermediary structure blocks heat transfer from the metal shell to the base, protecting the base from thermal degradation while adding minimal structural complexity.
Solution Approach 2:
The connection member is constructed as a composite structure combining resin material for insulation and metal components for structural strength. This composite approach allows the connection member to simultaneously provide thermal insulation to protect the resin base from heat while maintaining the mechanical integrity needed for secure attachment to the metal shell.
3Productivity
If multiple separate components are used to attach the base to the metal shell, then the attachment can be secure, but the number of components increases and productivity decreases
Solution Approach 1:
The invention merges multiple functions into a single integrated connection member: positioning (via positioning protrusion), insulation (via insulating portion), and attachment (via engagement groove). This consolidation reduces the number of separate components needed for secure attachment, thereby improving manufacturing efficiency and productivity while maintaining reliable fixation of the resin base to the metal shell.
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
This design enhances productivity, reduces component count and cost, suppresses thermal degradation, and improves safety by reducing the sensor's protrusion from the intake system, maintaining airtightness, and simplifying manufacturing processes.
Implementation Method 1
a sealing member that prevents gas leakage between the metal shell and the base
Implementation Method 2
heat of the metal shell is directly transferred to the base and may cause thermal degradation of the base
Data Source
AI summary
A gas sensor includes a gas sensor element that extends in an axial direction and that includes a detector, which detects a specific gas in a mixed gas; a metal shell that surrounds a periphery of the gas sensor element to hold the gas sensor element; a base that is disposed on a rear side of the metal shell and that covers a rear end portion of the gas sensor element, the base being made of a polymer material; and a metal tube that connects the metal shell and the base to each other and that includes a rear portion and a front portion, the rear portion being integrated with the base, the front portion forming an exposed portion that is exposed from the base. A part of the exposed portion of the tube is connected to the metal shell, and the base is disposed apart from the metal shell.