Capacitive Sensor Apparatus for Adhesive-Free Stress Measurement
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Solution Overview
Problem
The accuracy of strain gauge sensors is compromised due to the rigidity changes of adhesives used to attach them to measured objects, leading to inaccurate stress measurements.
Innovation Solution
A sensor apparatus featuring a cylindrical bracket with polar plates and leading wires forming a capacitor, allowing direct rigid contact with the object, which converts stress changes into capacitance value changes for accurate measurement without adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive is used to attach strain gauge sensor to measured object, then sensor can be mounted on surface, but measurement accuracy decreases due to rigidity change of adhesive
Solution Approach 1:
The patent removes the adhesive layer from the sensor structure, extracting the source of measurement error. The strain gauge sensor is designed to be directly mounted on the measured object surface without adhesive, eliminating the rigidity change problem that causes inaccurate stress measurements.
Solution Approach 2:
The patent introduces a special mounting structure as an intermediary between the sensor and measured object. This structure provides direct mechanical contact and force transmission without using adhesive, serving as a mediator that maintains measurement accuracy while enabling sensor attachment.
2Ease of operation
If adhesive is used to transmit stress-induced deformation, then sensor can be attached to object surface, but correctness of measurement result is affected
Solution Approach 1:
The adhesive layer is completely removed from the force transmission path. The sensor mounting structure directly contacts the measured object surface, extracting the intermediary adhesive that causes measurement inaccuracy while maintaining ease of sensor attachment.
Solution Approach 2:
Instead of using adhesive to bond the sensor to the object, the patent inverts the approach by using a mechanical mounting structure that clamps or presses the sensor against the surface. This reverse methodology achieves both easy attachment and accurate measurement without adhesive interference.
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 approach enables precise stress measurement by converting stress-induced changes into capacitance values, thereby overcoming the limitations of adhesive-based strain gauge sensors and improving measurement accuracy.
Implementation Method 1
the first polar plate and the first leading wire form a first electrode of a capacitor, the second polar plate and the second leading wire form a second electrode of a capacitor
Implementation Method 2
A stress sensor mainly converts stress-induced deformation of a to-be-measured object into a resistance change or a capacitance change to implement stress measurement
Data Source
AI summary
In one example implementation, a sensor apparatus includes a bracket, a first polar plate, a first contact portion, a first leading wire, a rotating shaft, a support frame, a second polar plate, a second contact portion, and a second leading wire. The bracket is of a cylindrical structure with two open ends. The first leading wire is disposed on the first polar plate and an external side of the bracket, one end of the first leading wire is connected to the first contact portion, and the other end of the first leading wire is connected to the first polar plate. The second contact portion is disposed at a first end of the support frame. The second leading wire is disposed on the support frame and the second polar plate.