Small Load Sensor with Restricting Units
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Solution Overview
Problem
Existing small-sized load sensor units are cumbersome to develop and assemble, lack responsiveness to load variations, and are prone to breakage under excessive loads, making them inefficient for high-resolution load and differential pressure measurements.
Innovation Solution
A small-sized load sensor unit with a pressure member, strain body, strain measuring unit, amplifying unit, first restricting unit, and second restricting unit, which together provide excellent responsiveness and prevent breakage by restricting excessive loads through adjustable mechanisms and stopper structures, allowing accurate measurement of pressing forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain body and strain measuring unit are designed for high-resolution load measurement, then measurement precision is improved, but the strain body becomes more fragile and prone to breakage under excessive loads
Solution Approach 1:
The patent applies beforehand cushioning by providing a stopper mechanism that prevents excessive deformation of the strain body before breakage can occur. The stopper is positioned to limit the displacement of the strain body under unexpected stress conditions such as excessive loads or falling, thereby protecting the fragile high-precision strain body from damage while maintaining its sensitivity for normal measurements
2Measurement precision
If the strain body thickness is reduced to increase displacement amount for high-resolution measurement, then measurement sensitivity is improved, but the strain body becomes more susceptible to breakage
Solution Approach 1:
The stopper mechanism serves as a protective measure that compensates for the reduced strength of thin strain bodies. By limiting the maximum displacement to a predetermined amount, the stopper ensures that even though the strain body is made thin for high sensitivity, it will not be subjected to stresses that would cause breakage during abnormal conditions
3Reliability
If a stopper mechanism is added to prevent strain body breakage, then reliability is improved, but device complexity increases
Solution Approach 1:
The stopper mechanism is merged with the existing sensor unit structure, where the stopper and its supporting components are integrated into the overall assembly. This combining approach allows the protection function to be added without creating entirely separate systems, thereby limiting the increase in device complexity while achieving reliable protection of the strain body
4Reliability
If multiple restriction mechanisms are provided for center and edge loads, then reliability under various loading conditions is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The protection mechanism is segmented into different components that handle different loading conditions: a first restricting unit for center loads and a second restricting unit for edge loads. This segmentation allows each component to be optimized for its specific function and simplifies the overall design by dividing the protection task into manageable parts that can be manufactured and assembled independently
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 enables rapid assembly, high reliability, and effective prevention of breakage under excessive loads, enhancing the sensor's responsiveness to load variations and improving measurement accuracy for both center and edge loads.
Implementation Method 1
a strain measuring unit which is provided on the strain body and is configured to be deformed together with the strain body when the pressing force is applied, and which is configured to measure a magnitude of the pressing force based on a deformation amount of the strain measuring unit
Data Source
AI summary
A small-sized load sensor unit including a pressure member, to which a pressing force is applied, a strain body which is fixed to the pressure member by a first fixing member, a strain measuring unit which is provided on the strain body and is configured to be deformed together with the strain body, a first restricting unit which restricts a pressing force applied to a substantially center portion of the pressure member such that the pressing force becomes a predetermined threshold value or less, and a second restricting unit which restricts the pressure member from moving by a predetermined amount or more when a pressing force of an excessive load is applied to an edge portion of the pressure member.