Actuator Housing Load Cell Layout for Precise Brake Force Sensing

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Solution Overview

Problem

Existing electromechanical actuators in aircraft and large vehicle brake systems face challenges in accurately measuring braking torque due to the limitations of load cell positioning and strain gauge placement within the actuator housing, which can lead to inaccurate force sensing and potential physical property changes under excessive loads.

Innovation Solution

The design incorporates a relief in the actuator drive unit housing with columns to orient the direction of force through a load cell and a strain gauge, which is flush-mounted and recessed within the housing, allowing for effective routing of sensor wires and improved communication with sensors, amplifiers, or control units, thereby enhancing force measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the load cell is installed within the actuator housing, then the force sensing capability is provided, but the measurement precision is reduced due to positioning limitations and potential physical property changes under excessive loads

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidload cell positioning complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates the load cell directly into the actuator drive unit housing, merging the sensing function with the structural housing. The load cell becomes an integral part of the housing rather than a separate component, which simplifies positioning and improves measurement accuracy by eliminating interface errors between separate parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a specific localized region within the housing where the load cell is positioned to optimally sense the braking force. The housing structure is designed with specific geometric features at the load cell location to ensure accurate force transmission and measurement, rather than treating the entire housing uniformly.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the strain gauge is mounted on the actuator housing, then the force measurement is enabled, but the manufacturing precision is reduced due to mounting variations and wire routing complexity

Engineering Contradiction:
Improvestrain gauge mounting easeVSAvoidstrain gauge placement precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent incorporates pre-formed mounting features and recesses into the actuator housing during the housing manufacturing process. These pre-prepared locations guide the strain gauge placement, ensuring consistent and precise positioning without requiring complex post-manufacturing adjustments or specialized installation procedures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The housing structure itself provides the mounting mechanism for the strain gauge through integrated recesses and alignment features. The housing serves both its structural function and the function of positioning the sensing element, eliminating the need for separate mounting hardware or complex installation procedures.

Inventive Principle:
Principle #25Self-service

3Weight of moving object

If the load cell is integrated into the actuator drive unit housing, then the weight and space are reduced, but the reliability is reduced due to potential excessive physical property changes under load

Engineering Contradiction:
Improveactuator weightVSAvoidload sensing reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent employs materials with composite or engineered properties for the actuator housing that provide both the necessary mechanical strength to withstand braking loads and the appropriate physical property stability for accurate load cell operation. The housing material is selected or designed to minimize thermal expansion, moisture absorption, and other physical changes that could affect measurement reliability.

Inventive Principle:
Principle #40Composite materials

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 configuration enables precise measurement of linear loads, reduces manufacturing and instrumentation time, and provides weight and space savings, resulting in improved performance and cost-effectiveness for brake actuator systems.

Implementation Method 1

a strain gauge coupled to the column

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Data Source

PatentEP3208485B1Actuator drive unit with load cell
Publication Date: 2023.12.20 GOODRICH CORP
  • EP3208485B1 patent drawingFigure 1
  • EP3208485B1 patent drawingFigure 2
  • EP3208485B1 patent drawingFigure 3

AI summary

The present disclosure provides an electromechanical actuator (300) comprising an actuator drive unit housing (230), a relief (395, 405) formed in the actuator drive unit housing, a column (380, 381, 410, 411) defined by the relief (395, 405) positioned adjacent to a second relief, and a load cell (370) comprising the column (380, 381, 410, 411) and a strain gauge (377) coupled to the column.