Pressure Sensor Support Ring Segmentation and Gel Management
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Solution Overview
Problem
Conventional pressure sensors face challenges in manufacturing cost, reliability, and assembly complexity, particularly in automotive applications, due to issues with support ring formation, gel flow management, and expensive contact assemblies.
Innovation Solution
A pressure sensor design featuring a support ring with interference fit slits and planar mounting tabs, an oversized wire bond window, and gel flow barriers with non-wetting surfaces, which simplifies manufacturing, reduces costs, and eliminates the need for additional components, while using symmetrical springs for contact assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional support rings are made with uniform thickness and precise geometry, then weld quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The support ring is segmented with interference fit slits that divide the ring structure into flexible segments. This segmentation allows the ring to accommodate tolerance variations and form adequate weld laps without requiring uniformly precise geometry throughout the entire ring, thereby reducing manufacturing complexity while maintaining weld quality.
Solution Approach 2:
The patent changes the geometric parameters of the support ring by introducing variable thickness regions and interference fit slits. These parameter changes allow the ring to compensate for manufacturing tolerances and achieve adequate weld laps through flexible deformation rather than requiring precise uniform geometry, thus improving weld quality without increasing overall manufacturing complexity.
2Reliability
If gel is dispensed to protect wire bonds and strain gauges, then reliability is improved, but gel bubbles and voids can cause mechanical damage and corrosion
Solution Approach 1:
The interference fit support ring acts as an intermediary structure between the gel and the strain gauge assembly. Its flexible nature allows it to accommodate gel volume changes and displace air during gel dispensing, serving as a mediator that prevents gel bubbles and voids from forming in critical areas, thereby maintaining reliability without the harmful effects of gel defects.
3Ease of manufacture
If rectangular wire bond windows are used in PCBs, then manufacturing is simplified, but gel flow to peripheral glass areas is blocked
Solution Approach 1:
The patent introduces dynamic flexibility into the system through the interference fit support ring, which can deform to accommodate gel flow. This dynamic structure compensates for the static limitation of rectangular wire bond windows, allowing gel to reach peripheral glass areas while maintaining the simple rectangular window design for ease of manufacture.
4Ease of operation
If additional components like gel dams are added to manage gel flow, then gel flow control is improved, but device complexity and cost increase
Solution Approach 1:
The interference fit support ring serves multiple functions: it provides mechanical support for the strain gauge assembly, manages gel flow through its flexible deformation, and prevents gel bubbles. By making the support ring multi-functional, the patent eliminates the need for separate gel dam components, thereby improving gel flow control without increasing device complexity.
Solution Approach 2:
The patent merges the gel flow management function into the support ring structure itself. The flexible support ring combines mechanical support and gel management into a single integrated component, eliminating the need for separate gel dam components and reducing overall device complexity while maintaining effective gel flow control.
5Productivity
If high-volume manufacturing is pursued, then productivity increases, but manufacturing precision and reliability may suffer
Solution Approach 1:
The segmented structure with interference fit slits provides self-aligning and self-compensating features that tolerate manufacturing variations. This segmentation allows high-volume manufacturing with relaxed tolerances while maintaining consistent assembly quality, as the flexible segments automatically compensate for dimensional variations.
Solution Approach 2:
The patent employs parameter changes in the support ring geometry (variable thickness, interference fit slits) that create a flexible structure capable of accommodating manufacturing tolerances. This allows high-volume production with consistent quality, as the flexible parameters compensate for variations inherent in high-volume manufacturing processes.
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 manufacturing efficiency, reliability, and cost-effectiveness by providing a larger process window for welding, improved gel flow management, and reduced component complexity, facilitating high-volume production and robust handling.
Implementation Method 1
a support ring including at least one mounting tab and a plurality of interference fit slits to provide a flexible interference fit between the sense element port and the support ring such that opposing side walls of sense element port and the support ring form a substantially flush lap joint
Implementation Method 2
gel flow barriers with non-wetting surfaces, which simplifies manufacturing, reduces costs, and eliminates the need for additional components
Implementation Method 3
The planar mounting tabs provide stable support for a single electronics board and elastic contact members
Data Source
AI summary
A pressure sensor includes a sense element port, a support ring and a plurality of interference fit slits to provide a flexible interference fit between the sense element port and the support ring to form a substantially flush lap joint. The sensor also includes an electronics board inside the support ring and attached to planar mounting tabs which provide a stable mounting. Gel flow barriers protect electronics board features from unwanted non-conductive gel. Double-ended symmetrical, tapered contact springs provide manufacturing cost savings and contribute to improved alignment of an interface connector of the sensor.