Torque-Measuring Coupling With Protected Strain Gauge Sleeve

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Solution Overview

Problem

Existing torque measuring couplings in industrial applications are costly, vulnerable to external influences, and require complex designs that hinder accurate torque measurement due to the need for multiple strain gauges and unprotected measurement regions.

Innovation Solution

A torque measuring coupling design featuring a strain gauge sleeve with a tapered expansion sleeve, protected strain gauges, and a coil ring that includes a protective tube and sealed circuit board, allowing for simple shaft connections and axial feedthrough while minimizing external interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strain gauges and spring elements are used to achieve accurate torque measurement, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvetorque measurement accuracyVSAvoidnumber of strain gauges and spring elements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The strain gauge sleeve is divided into multiple measurement regions along its axial extension, with strain gauges arranged in distinct patterns for different measurement purposes. This segmentation allows accurate torque measurement while organizing the complexity into manageable, functional sections rather than requiring a single complex gauge arrangement

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The strain gauge sleeve serves multiple functions simultaneously: it measures torque through strain gauges, provides mechanical coupling between shafts, and compensates for misalignments. This multi-functionality reduces the need for separate components, thereby lowering device complexity while maintaining measurement precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If the strain gauge sleeve is designed with open connections for easy assembly, then ease of manufacture is improved, but reliability decreases due to vulnerability to external influences

Engineering Contradiction:

Improveassembly simplicityVSAvoidprotection against mechanical influences

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The strain gauge sleeve is inserted into a protective housing that encloses the measurement regions. This nested structure protects the strain gauges from external mechanical influences while maintaining relatively simple assembly procedures, as the sleeve can still be inserted into the housing after the gauges are applied

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If a closed flange design is used to protect measurement regions, then reliability is improved, but axial passage becomes impossible and manufacturing complexity increases

Engineering Contradiction:

Improveprotection of measurement regionsVSAvoidaxial feedthrough capability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The housing provides localized protection over the strain gauge measurement regions rather than requiring a completely closed flange design. This allows the measurement regions to be protected from external influences while leaving axial passages open for feedthrough, achieving reliability without sacrificing manufacturing ease or axial accessibility

Inventive Principle:

Principle #3Local quality

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 design provides cost-effective, robust torque measurement with improved accuracy by protecting strain gauges and reducing complexity, enabling efficient compensation for shaft misalignments and external influences.

Implementation Method 1

The arrangement of these strain gauges in the region of the tapered cross-section and on the described spring elements allows accurate measurement even if the shaft axes are displaced relative to each other.

Methodology Applied

Scientific EffectStrain gauge measurement: Piezoresistive Effect

Implementation Method 2

If a torque is transmitted with the torque measuring coupling, the greatest elastic deformation occurs in the region of the tapered sleeve portion

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS20250290812A1Torque-measuring coupling

Publication Date: 2025.09.18 CHRISTIAN MAYR GMBH & CO KG

AI summary

The invention relates to a torque measuring coupling, which consists of a stator, a strain gauge sleeve, and, optionally, hubs connected thereto via lamellar connections. The torque measuring coupling is suitable for transmitting torque, compensating for shaft misalignment, and measuring the transmitted torque. The strain gauge sleeve is constructed in several parts, wherein in particular the expansion sleeve is radially enclosed by a coil ring and positively connected to a flange. The coil ring has an inner diameter, which is smaller than the outer diameter of the flange, and accommodates a protective tube.