Load Sensor Pressing Member Structure for Tolerance and Linearity

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Solution Overview

Problem

Load sensors face challenges in achieving high detection accuracy and linearity while ensuring proper assembly tolerances, as precise alignment is required for the load-bearing member and load sensing element to function effectively.

Innovation Solution

A load sensing apparatus is designed with a pressing member comprising an elastic member, a stiff pressing portion, and an elastic supporting portion, allowing a gap between the stiff pressing portion and the pressure sensing portion to facilitate assembly tolerances, while using a stiff pressing portion made of a highly stiff material to enhance detection sensitivity and linearity through efficient load transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the load sensing element and load-bearing member are accurately aligned to achieve high detection accuracy, then the measurement precision is improved, but the assembly difficulty increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidassembly difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

A pressing member is introduced as an intermediary component between the load-bearing member and the pressure sensing portion. The pressing member includes a pressing portion that contacts the load-bearing member and a pressing tip that contacts the pressure sensing portion, mediating the force transmission and eliminating the need for direct alignment between the load-bearing member and sensing element.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The pressing member is divided into distinct functional portions: a pressing portion for receiving the load, an elastic supporting portion for providing flexibility and positioning, and a pressing tip for transmitting force to the sensor. This segmentation allows each portion to be optimized independently and simplifies assembly.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If a stiff pressing portion is used to reduce runout and enhance detection sensitivity, then the measurement precision is improved, but the assembly tolerances become more difficult to accommodate

Engineering Contradiction:

Improvedetection sensitivityVSAvoidassembly tolerances

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The pressing member exhibits local quality variation: the pressing portion and pressing tip are made stiff (with elastic modulus of 1 GPa or more) to reduce runout and enhance detection sensitivity, while the elastic supporting portion is made flexible to accommodate assembly tolerances and provide positioning functionality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The pressing member is constructed as a composite structure combining materials with different elastic moduli - stiff materials (metal or silicon with elastic modulus ≥1 GPa) for the pressing portion and tip, and flexible materials for the elastic supporting portion. This composite construction allows simultaneous achievement of high detection sensitivity and easy assembly.

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If the pressing member is made entirely of stiff material to eliminate runout, then the detection sensitivity is improved, but the assembly becomes more difficult and collision risk increases

Engineering Contradiction:

Improvedetection sensitivityVSAvoidassembly ease

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The elastic supporting portion acts as a cushioning element that prevents collision between the pressing member and the pressure sensing portion during assembly. It provides beforehand protection against potential damage while maintaining the stiff pressing tip for accurate measurement.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 apparatus achieves high-accuracy load detection with reduced runout and improved measurement sensitivity by efficiently transmitting loads through the elastic and stiff components, ensuring reliable operation despite assembly variations.

Implementation Method 1

an elastic member that receives a load

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

incorporating piezoresistive elements for enhanced measurement linearity

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS12613150B2Load sensing apparatus with pressing member having elastic member and rigid pressing portion

Publication Date: 2026.04.28 ALPS ALPINE CO LTD

AI summary

A load sensing apparatus according to an aspect of the present invention includes a load sensing element including a pressure sensing portion, a housing that houses the load sensing element, and a pressing member supported by the housing, wherein the pressing member includes an elastic member that receives a load, a stiff pressing portion that is to come into contact with the pressure sensing portion, and an elastic supporting portion that supports the stiff pressing portion in the housing. When no load is applied to the pressing member, a gap is formed between the stiff pressing portion and the pressure sensing portion.