Pressure Sensor Curved Web Strain Gauge Design
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Solution Overview
Problem
Existing pressure sensors face challenges in achieving precise and reproducible measurements at low pressures, particularly in compact designs with small diameters, due to limitations in long-term stability, high temperature loads, and interference from exhaust gas residues, and they often require frequent recalibration and are expensive.
Innovation Solution
A pressure sensor design featuring a support element with a curved web that changes curvature in response to force, allowing a strain measuring element to be attached, enabling high strain values even at low pressures and small membrane diameters, and incorporating a metallic film strain gauge or piezoresistive elements for sensitive measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoresistive technology is used for pressure measurement, then measurement sensitivity is improved, but long-term stability deteriorates and recalibration frequency increases
Solution Approach 1:
The patent replaces expensive piezoresistive silicon measuring cells with a more durable strain gauge-based measuring cell that uses a deformable membrane and strain gauges arranged in a Wheatstone bridge configuration. This substitution prioritizes long-term stability and reduced recalibration needs over maximum sensitivity, accepting a trade-off in measurement precision for improved reliability.
2Measurement precision
If piezoresistive sensors are used, then measurement sensitivity is improved, but device cost increases
Solution Approach 1:
The patent employs strain gauges and a deformable membrane construction that are significantly less expensive than piezoresistive silicon measuring cells. The strain gauges can be manufactured using conventional techniques and arranged in a Wheatstone bridge configuration, reducing overall device cost while maintaining adequate measurement capability for the intended application range.
3Measurement precision
If strain gauge structure is arranged on deformable membrane, then measurement capability is improved, but available space for strain gauge arrangement is limited in compact sensors
Solution Approach 1:
The patent divides the measuring cell into distinct functional zones: a deformable membrane for pressure transmission, a support structure for mechanical stability, and strategically positioned strain gauge locations. The strain gauges are arranged in specific patterns (such as radial and circumferential orientations) on the membrane or support structure, allowing adequate spacing and signal differentiation within a compact overall footprint.
Solution Approach 2:
The patent utilizes three-dimensional positioning of strain gauges on the deformable membrane and support structure, arranging them in multiple layers and orientations rather than simply spreading them out on a two-dimensional surface. This spatial arrangement maximizes the use of available volume and allows sufficient separation between gauge elements even in compact sensor designs.
4Length of moving object
If pressure sensor uses small diameter for compact design, then device size is reduced, but strain values at low pressures decrease
Solution Approach 1:
The patent employs a deformable membrane with optimized curvature and thickness profiles that amplify strain responses even at small diameters. The membrane geometry is designed to concentrate stress in specific regions where strain gauges are positioned, maximizing the strain signal for a given pressure input despite the compact overall sensor size.
Solution Approach 2:
The patent uses composite construction combining the deformable membrane material with a rigid support structure, creating a mechanically optimized system. The membrane material is selected for its ability to deform elastically under pressure while the support structure provides stability and positions the strain gauges in high-strain regions, enhancing measurement sensitivity in compact configurations.
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 enables precise and reproducible pressure measurements across low pressure ranges while maintaining a compact form factor, reducing interference and the need for frequent recalibration, and improving measurement dynamics.
Implementation Method 1
a strain measuring element for obtaining a measurement signal dependent on the pressure to be measured
Implementation Method 2
the curvature or radius of curvature of which changes depending on the force introduced by the sensor membrane
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a pressure sensor (10) for static and dynamic pressure measurements, comprising a sensor housing (11) and a sensor membrane (12) arranged on the pressure side of the sensor housing. A support element (15) is arranged in the sensor housing (11) and is oriented perpendicular to the membrane plane (ε). This support element is in at least indirect contact with the sensor membrane (12), is frictionally supported on the sensor housing (11), preferably on its base (14), and includes a strain gauge (20) for generating a measurement signal dependent on the pressure to be measured. According to the invention, the support element (15) has at least one curved web (16) along its longitudinal extent, the curvature or radius of curvature of which changes depending on the force applied by the sensor membrane (12). A sensitive part (21) of the strain gauge (20) is attached to the curved web (16).