Force-Measuring Sleeve with Recessed Strain Gauges

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Solution Overview

Problem

Existing force transducers for measuring axle forces are limited in measuring radial forces accurately due to interference between neighboring sleeves, require significant space, and can only detect bending forces, failing to account for shearing forces.

Innovation Solution

A force-measuring sleeve with recesses and force transmission surfaces arranged in a common plane perpendicular to the longitudinal axis, allowing direct force transmission to strain gauges for reliable measurement of radial forces and accommodating multiple sleeves without interference, while reducing axial space requirements and enabling detection of various force types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple force-measuring sleeves are placed on an axle to measure forces from multiple deflection wheels, then the measurement coverage is improved, but the measurement precision deteriorates due to mutual interference between neighboring sleeves

Engineering Contradiction:
Improvemeasurement coverageVSAvoidmeasurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The force transmission path is segmented into distinct zones: the force introduction surface receives forces from deflection wheels, these forces are transmitted through the sleeve wall to bearing surfaces that contact the axle. The strain gauges are positioned in recesses on the inner circumference to measure only the forces transmitted through this specific path, isolating the measurement from interference by neighboring sleeves.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the force transmission surfaces and measuring points are arranged laterally offset in the axial direction, then the force transmission path is established, but the device length increases requiring considerable space

Engineering Contradiction:
Improveforce transmissionVSAvoidaxle length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

Instead of arranging force transmission surfaces and measuring points at different axial positions (one-dimensional arrangement), the invention places both the force introduction surface and the strain gauge-equipped bearing surfaces in the same axial plane. The force transmission occurs through the radial thickness of the sleeve wall, transforming the arrangement from axial separation to radial transmission, thereby reducing the axial length requirement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If conventional force transducers are used that can only detect bending forces, then the device complexity is reduced, but the measurement precision deteriorates by failing to detect shearing forces

Engineering Contradiction:
Improvedevice simplicityVSAvoidforce detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The force-measuring sleeve is designed with universal measuring capability by positioning strain gauges in recesses on the inner circumference of the sleeve wall. This configuration enables the single device to detect both bending forces (radial forces) and shearing forces (axial forces), as the strain gauges can measure deformations in multiple directions resulting from different force components acting on the sleeve.

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

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

Enables accurate measurement of radial forces and shearing forces, reduces space requirements, and allows for the detection of multiple force distributions without interference, facilitating the measurement of compression, bending, and shearing forces.

Implementation Method 1

strain gauges are inserted. The groove runs laterally offset and perpendicular to the contact surface between the sleeve and the axle, so that the forces introduced by the deflection roller bend the axle, causing geometric changes in the grooves that are excluded from the strain gauges, so that the changes in resistance of the Strain gauges are generated electrical signals

Methodology Applied
Scientific EffectStrain gauge effect: Piezoresistive Effect

Data Source

PatentEP2362200B1Power measurement sleeve and power measurement device
Publication Date: 2015.05.27 BROSA AG
  • EP2362200B1 patent drawingFigure 1a
  • EP2362200B1 patent drawingFigure 1b
  • EP2362200B1 patent drawingFigure 1c

AI summary

The sleeve (11) has inner and outer force transmission surfaces (13, 14) completely or sectionally aligned to each other. A recess (15) is provided in the inner or outer surface, and has a symmetric axis (17) aligned perpendicular to a longitudinal axis (12) of the sleeve. An elongation measuring strip (10) is attached at a base (16) and/or a wall (16') of the recess. Two supports (18) are arranged at the outer or inner surface in a circular- or spherical path, where one of the supports is provided opposite to the recess and extends in a circumferential direction of the sleeve. An independent claim is also included for a force measurement device comprising a force measurement sleeve.