Magneto-Elastic Tow Coupling Sensing for Accurate Load Detection

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Solution Overview

Problem

Existing tow coupling systems rely on strain gauges that require structural weakening, leading to instability and high complexity, and lack advanced features like load weight gauging, shift alerts, and stability control.

Innovation Solution

A magneto-elastic sensor assembly with load sensor pins and magnetic field sensors to measure stress and strain without compromising structural integrity, capable of determining load direction and magnitude, and integrating with vehicle control systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strain gauges are used for sensing force load on a hitch, then load measurement is enabled, but structural stability of the measuring device is compromised

Engineering Contradiction:
Improveload measurementVSAvoidstructural stability
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent replaces traditional strain gauge-based mechanical sensing with a magnetosensor system that uses magnetic field sensing to detect load forces. The magnetosensor assembly includes a magnetically polarized region on the pin and a magnetosensor that detects changes in the magnetic field caused by applied forces, eliminating the need for structural weakening required by strain gauges.

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

2Measurement precision

If prior art load measurement devices are used for tow couplings, then load sensing is achieved, but device complexity and cost increase

Engineering Contradiction:
Improveload sensingVSAvoidmeasurement and control devices
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the sensing function from complex mechanical strain measurement systems and implements it through a simpler magnetosensor-based system. The solution removes unnecessary mechanical components and control mechanisms while retaining the essential load sensing capability through magnetic field detection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs cost-effective magnetosensor technology that eliminates the need for expensive strain gauge installations and complex structural modifications. The magnetosensor assembly can be implemented as a more affordable alternative to traditional load measurement systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If weight distribution tow hitch system is used, then towing stability is improved, but ability to monitor distributed forces is insufficient

Engineering Contradiction:
Improvetowing stabilityVSAvoidmonitoring of distributed forces
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the magnetosensor continuously monitors the forces applied to the weight distribution tow hitch system. The system provides output signals that indicate the magnitude and direction of applied forces, enabling real-time monitoring and potential closed-loop control of the towing system.

Inventive Principle:
Principle #23Feedback

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

Provides accurate load measurements, reduces structural weakening, and enables advanced features like load alerts and stability control, enhancing towing safety and efficiency.

Implementation Method 1

a magneto-elastically active region that produces a magnetic field varying with stress applied to the pin

Methodology Applied
Scientific EffectMagneto-elastic effect: Magnetoelastic Effects

Data Source

PatentEP3858646B1Towing systems and methods using magnetic field sensing
Publication Date: 2026.04.08 METHODE ELECTRONICS INC
  • EP3858646B1 patent drawingFigure 1A~1E
  • EP3858646B1 patent drawingFigure 2A~4
  • EP3858646B1 patent drawingFigure 5~8

AI summary

A magneto-elastically-based active force sensor, used with a tow coupling between a towed and a towing vehicle or a coupling between a vehicle body and a suspension of the vehicle, which outputs a signal useful for determining forces acting on the coupling. The outputted force information may be provided by processor-enabled embedded software algorithms that take inputs from the force sensor and other sensors, may be used by one or more vehicle systems during operating of the vehicle, such as engine, braking, stability, safety, and informational systems. The force sensor includes directionally-sensitive magnetic field sensing elements inside the sensor, and shielding may be used around the sensors to reduce the influence of external magnetic fields on the sensing elements. The force sensor may be used with different tow and vehicle weight sensing coupling devices installed on different types of automobile cars and trucks.