Torquemeter Dual-Load Path Design for Transient Torque Management

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Solution Overview

Problem

Existing torquemeters face challenges in accurately measuring torque while transmitting large transient torques without overstressing components, and they often fail to meet the requirements of modern turbo-machinery operating at higher power and speeds, particularly when designed for lower nominal torque levels.

Innovation Solution

A dual-load path torquemeter design featuring a one-piece coupling with axially spaced spokes and pins that engage only when a predetermined torque magnitude is exceeded, allowing for torque transfer through multiple paths to prevent component stress and enable accurate measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the torquemeter is designed for a lower nominal torque level to achieve desired measurement accuracy, then measurement precision is improved, but the device cannot transmit large transient torques without overstressing components

Engineering Contradiction:

Improvetorque measurement accuracyVSAvoidtransient torque transmission capacity

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The torquemeter is divided into two distinct load paths: a primary load path containing torque-sensing elements for accurate measurement, and a secondary load path with pins that engage only during transient overload conditions. This segmentation allows each path to be optimized for its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The load path configuration is made dynamic through the pin mechanism that transitions from disengaged to engaged state based on torque magnitude. During normal operation, only the primary path carries load for precise measurement; during transient overloads, pins engage to create a parallel load path that protects sensing elements.

Inventive Principle:

Principle #15Dynamics

2Strength

If the torquemeter is designed to transmit the full maximum transient torque, then strength and reliability are improved, but measurable torsional twist does not occur and torque measurement becomes inaccurate

Engineering Contradiction:

Improvetransient torque transmission capacityVSAvoidtorque measurement accuracy

Core Design Contradiction:

StrengthVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pin-based secondary load path is designed to carry only the excessive transient torque portion that exceeds the primary path's safe operating limit. This partial action approach allows the sensing elements to remain within their optimal measurement range while still protecting the system from catastrophic failure.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If a flexible element is made the weakest link in the driveline to contain catastrophic failure, then safety is improved, but the torquemeter must be rated to transfer greater torque than the weakest link

Engineering Contradiction:

Improvefailure containment capabilityVSAvoidtorque transfer rating

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The pin mechanism acts as a pre-designed cushioning element that engages before catastrophic failure can occur. During transient overloads, the pins absorb excess torque that would otherwise stress the flexible element beyond its safe limit, thereby protecting the driveline while allowing the torquemeter to be rated higher than the flexible element's torque capacity.

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 dual-load path design effectively accommodates transient torque fluctuations, ensuring accurate torque measurement and preventing component overstress, while meeting the demands of modern turbo-machinery by being capable of handling higher power and rotational speeds.

Implementation Method 1

The pin engages the second rim portion to transfer load between the first and second rim portions when a torque exceeding a predetermined magnitude is transferred through the coupling

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

a first rim portion adapted to be fixed for rotation with a rotary driving member, a second rim portion spaced apart from the first rim portion and adapted to be fixed for rotation with a rotary driven member

Methodology Applied

Scientific EffectTorsion: Torque

Data Source

PatentUS7665373B2Torque measuring device with redundant torque transmission paths and fail-safe mechanism

Publication Date: 2010.02.23 REGAL BELOIT AMERICA INC

AI summary

A torque transferring and monitoring device includes a coupling having a hub portion, a first rim portion, a first set of spokes radially extending between the hub portion and the first rim portion, a second rim portion spaced apart from the first rim portion and a second set of spokes radially extending between the hub portion and the second rim portion. The second set of spokes are axially spaced apart from the first set of spokes. A plurality of pins are fixed to the first rim portion. Each pin has a portion positioned in an aperture formed in the second rim portion. The pin is clear of the second rim portion when the coupling is in an unloaded state. The pin engages the second rim portion to transfer load between the first and second rim portions when a torque exceeding a predetermined magnitude is transferred through the coupling.