Meandering Conductor Track Layout for Accurate Torque Sensing

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Solution Overview

Problem

Existing torque sensors, such as strain gauges and conventional sensor devices, suffer from inaccuracies due to non-structure-specific alignment and adhesive aging, and are susceptible to thermal and parasitic forces, leading to unreliable torque measurement results.

Innovation Solution

A sensor device with alternating meandering conductor tracks on a substrate, arranged in concentric circles, measures torque by detecting resistance changes through interconnected structures that react to deformation, allowing for accurate torque determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If strain gauges are glued directly onto a test object, then the sensor can be applied to various applications, but the measurement accuracy is insufficient due to non-structure-specific alignment and adhesive aging

Engineering Contradiction:
Improveapplication versatilityVSAvoidtorque measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The conductor tracks are designed with specific local structures (meandering patterns, loop configurations) that are optimized for detecting torque in specific directions. Different regions of the sensor have different conductor track arrangements tailored to the local stress patterns, enabling both versatility across applications and high measurement accuracy through structure-specific optimization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent replaces the mechanical adhesive bonding process with a direct integration of conductor tracks into the substrate structure. Instead of gluing strain gauges onto the test object, the conductor tracks are formed as part of the substrate itself or directly integrated with it, eliminating adhesive aging issues and ensuring precise alignment with the substrate's principal stress directions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional sensor devices with resistance wire patterns are used, then torque detection is possible, but thermal effects and parasitic forces negatively impact the measurement result

Engineering Contradiction:
Improvetorque detection capabilityVSAvoidthermal effects and parasitic forces
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs asymmetric meandering patterns and non-uniform loop configurations in the conductor tracks. These asymmetric designs create differential responses to thermal expansion and parasitic forces, allowing the sensor to distinguish between true torque-induced deformation and spurious thermal/parasitic effects through compensated measurement circuits.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The conductor tracks incorporate curved meandering paths and loop structures that distribute thermal stress more uniformly throughout the sensor. The curved geometry reduces stress concentration points compared to straight wire patterns, minimizing the impact of thermal effects and parasitic forces on the resistance measurements.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If the conductor tracks are arranged in simple patterns, then the device complexity is low, but the measurement accuracy is insufficient

Engineering Contradiction:
Improveconductor track arrangementVSAvoidtorque measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the conductor track into multiple segments with different meandering patterns and loop configurations. Each segment can be optimized for specific torque components or measurement functions, allowing high measurement accuracy through segmented design while keeping the overall device complexity manageable through modular construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from simple one-dimensional wire patterns to two-dimensional meandering structures with loop configurations. This dimensional expansion allows the conductor tracks to engage with stress fields in multiple directions simultaneously, significantly improving torque measurement accuracy without proportionally increasing device complexity.

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

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 sensor device provides high accuracy in torque measurement by compensating for parasitic influences and ensuring consistent temperature distribution across the conductor tracks, enhancing measurement reliability.

Implementation Method 1

These structures are continuously interconnected via connecting sections, which are also conductor track segments. This allows the sensor device to determine the torque load on the substrate by measuring the resistance of the first and second conductor tracks.

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP4443124B1Sensor device
Publication Date: 2026.01.21 DR JOHANNES HEIDENHAIN GMBH
  • EP4443124B1 patent drawingFigure 1~2
  • EP4443124B1 patent drawingFigure 3~4
  • EP4443124B1 patent drawingFigure 5~6

AI summary

The invention relates to a sensor device (1) for torque measurement comprising a substrate (2), a first conductor track (3.1) and a second conductor track (3.2), wherein the first conductor track (3.1) and the second conductor track (3.2) are arranged on the substrate (2) and each comprise at least one area with structures (3.101-3.132; 3.201-3.232) which are designed in a meandering shape. The structures (3.101-3.132) of the first conductor track (3.1) and the structures (3.201-3.232) of the second conductor track (3.2) are each continuously connected to each other via connecting sections (V). The structures (3.101-3.132; 3.201-3.232) of the sensor device (1) enable the determination of the torque load on the substrate (2). The structures (3.101-3.132) of the first conductor track (3.1) and the structures (3.201-3.232) of the second conductor track (3.2) are arranged such that they run alternately along a curve (K).