Integral Load Cell Housing for Actuator Strain Measurement

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Solution Overview

Problem

Existing electric motor actuators in aircraft and large vehicle brake systems face inaccuracies in load measurement due to deflection and deformation of load cells under compressive loading, requiring frequent calibration and maintenance.

Innovation Solution

An integral load cell housing with strategically positioned strain gages on the actuator housing measures load in tension, minimizing the effects of deflection and edge loading by using a Wheatstone bridge configuration with transverse strain gages to normalize linear load measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a load cell is installed within the actuator housing and loaded in compression, then load measurement is enabled, but deflection and deformation occur creating inaccuracies in measurement

Engineering Contradiction:
Improveload measurement accuracyVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent inverts the conventional approach by loading the housing in tension rather than compression. The load cell is positioned to measure tensile loads on the housing, which eliminates deflection and deformation issues associated with compressive loading, thereby improving measurement accuracy and reliability

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts the load cell from a separate installation within the housing and integrates it directly into the housing structure itself. The housing becomes the load cell, eliminating the need for a separate compressively-loaded load cell component and its associated measurement errors

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If compressive loading is applied to the load cell, then load measurement function is achieved, but frequent calibration and maintenance are required

Engineering Contradiction:
Improveoperational efficiencyVSAvoidcalibration and maintenance time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

By inverting the loading mode from compression to tension, the housing structure becomes more stable and resistant to deformation, significantly reducing the frequency of calibration and maintenance required, thus improving operational efficiency

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent merges the housing structure with the load cell function, creating an integral housing-load cell system. This integration eliminates the need for separate calibration of a distinct load cell component, reducing maintenance time and improving productivity

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If strain gages are installed on the housing to measure load, then measurement capability is provided, but installation complexity increases

Engineering Contradiction:
Improveload measurement capabilityVSAvoidstrain gage installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The housing serves multiple functions: it provides structural support, contains internal components, and acts as the load cell itself through integrated strain gage measurement. This multi-functionality reduces overall system complexity despite the added measurement capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The strain gages are installed to measure tensile loads on the housing rather than compressive loads on a separate load cell. This inversion simplifies the installation by utilizing the housing's natural tensile strength and geometry, reducing installation complexity while maintaining measurement precision

Inventive Principle:
Principle #13The other way round (Inversion)

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 solution provides accurate load measurement, reduces calibration needs, and offers cost savings through reduced manufacturing and instrumentation time, while enhancing reliability and cost-effectiveness for electric motor actuators.

Implementation Method 1

The first strain gage may be installed on the housing. The second strain gage may also be installed on the housing.

Methodology Applied
Scientific EffectStrain gage measurement: Piezoresistive Effect

Implementation Method 2

an integral load cell housing with strategically positioned strain gages on the actuator housing measures load in tension, minimizing the effects of deflection and edge loading by using a Wheatstone bridge configuration with transverse strain gages to normalize linear load measurements

Methodology Applied
Scientific EffectWheatstone bridge: Wheatstone Bridge

Data Source

PatentEP2886904B1Integral housing load cell system and apparatus
Publication Date: 2020.09.16 GOODRICH CORP
  • EP2886904B1 patent drawingFigure 1
  • EP2886904B1 patent drawingFigure 2

AI summary

A strain gage system (40) for an electric motor actuator (10) is provided. The strain gage system (40) may be coupled to or integrally formed in a housing (20) of the electric motor actuator (10). In various embodiments, the strain gage system (40) may comprise one or more principle strain gages (40A, 40B). In various embodiments, the strain gage system (40) may comprise one or more transverse strain gages (40C, 40D).