Force Sensor With Flexible Wall For Small Force Measurement
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Solution Overview
Problem
Existing force sensors face challenges in accurately measuring small forces due to non-concentrated stress distribution, which affects the precision of strain gauge measurements.
Innovation Solution
A force sensor design featuring a main beam with a cavity between flexible and rigid walls, where strain gauges are fixed to the flexible wall near the intersection with a rigid connecting part, concentrating stress and allowing for precise measurement of small forces, and a cover plate for sealing and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strain gauges are attached to uniformly distributed flexible walls, then the structure has good flexibility and stress distribution, but it is difficult to measure small forces accurately due to non-concentrated stress
Solution Approach 1:
The patent applies local quality by creating a localized flexible region (thin wall portion) within the beam structure where stress concentrates. This thin wall portion has different mechanical properties (lower thickness) compared to the rest of the beam, creating a specific measurement zone that concentrates stress locally while maintaining overall structural integrity. The strain gauges are positioned at this specific location to detect the concentrated stress, resolving the contradiction between uniform flexibility and localized measurement precision.
2Device complexity
If strain gauges are positioned at spots with smallest distance to cutout holes, then the structure is simplified, but measurement precision is reduced due to deformation at multiple spots
Solution Approach 1:
The patent applies segmentation by dividing the beam into distinct functional zones: rigid portions for structural support and a localized flexible portion (thin wall) for stress concentration and measurement. This segmentation allows the majority of the structure to remain simple and rigid while creating a specific measurement zone. The strain gauges are positioned at the intersection of the thin wall and connecting part, where stress concentrates, enabling precise measurement without requiring complex multi-point gauge arrangements.
3Adaptability or versatility
If a vertical thinner zone is used to divide the beam into sub-beams, then force coupling is enabled, but the structure becomes more complex and measurement precision is reduced
Solution Approach 1:
The patent applies the taking out principle by extracting the measurement function from a complex multi-subbeam structure and concentrating it in a single localized thin wall portion. Instead of using multiple sub-beams with force coupling mechanisms, the invention isolates the stress concentration function to a specific thin wall region where strain gauges can directly measure the force applied to the load-receiving portion. This simplifies the structure while maintaining measurement precision.
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
Enables accurate measurement of small forces by concentrating stress on the strain gauges, improving measurement precision and reducing external influences like humidity and temperature gradients.
Implementation Method 1
The strain gauge is fixed to the flexible left wall... By fixing the strain gauges in the region close to the position where the flexible left wall intersects the first connecting part, the force sensor provided by the present invention can finely measure the change in the stress
Implementation Method 2
The main beam is provided with a cavity arranged between an upper wall, a lower wall, a flexible left wall and a rigid right wall... concentrating stress on the strain gauges
Data Source
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AI summary
Provided is a force sensor, comprising a first end portion (1), a second end portion (2), a parallel-guiding mechanism (3), a beam (4), and a strain gauge (5). The parallel-guiding mechanism (3) is used for connecting the first end portion (1) to the second end portion (2). The beam (4) comprises a main beam (43), a first connecting part (41) for connecting the main beam (43) to the first end portion (1), and a second connecting part (42) for connecting the main beam (43) to the second end portion (2). The main beam (43) comprises a flexible wall (435) connected to the first connecting part (41), and a rigid wall (432) connected to the second connecting part (42). The strain gauge (5) is fixed to the flexible wall (435). The force sensor can be used for measuring a relatively small force.