Lead-Free Pressure Sensor Connection with Adhesion Promoter
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Solution Overview
Problem
Existing pressure sensors face reliability issues under high pressures and temperature variations due to inadequate adhesive bonds between lead-free components, which are challenging to maintain over the entire range of use in terms of pressure and temperature.
Innovation Solution
The use of a lead-free aluminum alloy for the pressure connection, combined with surface roughening and a conformal adhesion promoter layer, enhances the adhesive strength and stability of connections between the pressure sensor, pressure port, and housing, allowing for reliable operation up to 40 bar operating pressure and temperatures from -40°C to 135°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive connections are used to connect pressure sensor to pressure port and housing, then assembly is simplified and manufacturing is easier, but the connection reliability deteriorates under high pressures and temperature variations
Solution Approach 1:
The surface properties of the pressure port are modified by changing parameters such as surface roughness (Ra 0.4-1.6 µm) and applying adhesion promoter layers, which transforms the adhesive connection from unreliable under high pressure to reliably withstanding 40 bar operating pressure and temperature cycling from -40°C to 135°C
Solution Approach 2:
The connection system uses a composite approach combining the pressure port material (aluminum alloy or steel), adhesion promoter layer, and adhesive material to create a multi-layer composite structure that achieves both ease of assembly and high reliability under extreme conditions
2Object-affected harmful factors
If lead-free materials are used for pressure connection components, then environmental compliance is improved, but adhesive bond strength deteriorates
Solution Approach 1:
The surface parameters of lead-free aluminum alloy components are optimized with specific roughness values (Ra 0.4-1.6 µm) and adhesion promoter applications, enabling adhesive bonds to achieve 40 bar pressure resistance and temperature stability from -40°C to 135°C, matching or exceeding the performance of traditional lead-based materials
3Strength
If surface roughening is applied to pressure connection surfaces, then adhesive strength is improved, but manufacturing complexity increases
Solution Approach 1:
The surface roughness is controlled within a specific range (Ra 0.4-1.6 µm) which can be achieved through standard blasting or machining processes, balancing adhesive strength improvement with manufacturing feasibility without requiring complex or specialized surface treatment equipment
Solution Approach 2:
Surface roughening and adhesion promoter application are applied locally only to the adhesive bonding areas of the pressure port, not the entire component, which minimizes additional manufacturing complexity while maximizing adhesive strength where it is most needed
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 provides durable adhesive connections that withstand high mechanical and chemical loads, reducing thermal expansion influences and eliminating the need for special sealing elements, ensuring consistent performance across varying conditions.
Implementation Method 1
the surface areas have a defined roughness and are covered with an adhesion promoter layer
Implementation Method 2
In order to produce the required adhesive strength of the adhesive surfaces with the adhesive material, at least the areas of the surface of the pressure connector with which a pressure-loaded adhesive connection is to be produced have special surface properties
Implementation Method 3
a lead-free aluminum alloy can be used for the pressure connection, which can withstand the high mechanical and also special chemical loads
Implementation Method 4
the adhesive connections described have proven to be stable over a high temperature range and even under high thermal cycling loads. Operating temperatures in the range from -40°C to 135°C and storage temperatures up to 150°C are possible
Data Source
Figure 1
AI summary
A pressure sensor and a method for its manufacture are described, comprising a housing, a housing connector, and a pressure port made of a lead-free material projecting into the housing. A pressure transducer is arranged in the pressure sensor and bonded to the pressure port, so that a passage in the pressure port is closed on one side. The pressure port has a roughened surface in one area and is provided with an adhesion promoter layer in this area, with the pressure transducer being bonded to the pressure port in this area. (Fig. 1)