Flexible Brake Force Sensor Film for Direct Rail Brake Measurement

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Solution Overview

Problem

Current methods for detecting braking forces in rail vehicles are error-prone due to uncertainties in pneumatic pressure application and require modification or replacement of brake systems, making it difficult to accurately measure forces without disrupting the system.

Innovation Solution

A flexible sensor device using a thin, adaptable piezoelectric sensor film with a magnetic adhesive film that can be inserted between brake pads and wheels, allowing direct measurement of braking forces without modifying the existing braking system, ensuring accurate force transmission and easy installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a flexible sensor film is used to directly measure braking forces, then measurement precision is improved, but the sensor device becomes difficult to install without modifying the brake system

Engineering Contradiction:
Improvebraking force measurementVSAvoidinstallation ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs a flexible sensor film that can be inserted into the gap between the brake pad and wheel without modifying the brake system. The film's flexibility allows it to conform to the curved surfaces and narrow spaces, enabling direct force measurement while maintaining ease of installation through simple insertion and magnetic attachment.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sensor film acts as an intermediary element inserted between the brake pad and wheel. This mediator enables direct force measurement without requiring modification of the existing brake components, as it fits into the existing gap and transmits force measurements from the contact interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If a rigid sensor device is used for force measurement, then measurement stability is improved, but the device cannot adapt to curved surfaces and narrow gaps

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidsurface adaptation
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The flexible sensor film can adapt to curved surfaces of brake pads and wheels while maintaining measurement stability. Its flexibility allows conformal contact with irregular geometries, ensuring stable force transmission and measurement across varying surface conditions without compromising measurement reliability.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sensor device transitions from a rigid structure to a dynamic, flexible film that can adjust its shape to match the brake system components. This dynamic adaptation enables the sensor to maintain stable measurements across different positions and surface conditions through elastic deformation rather than rigid fixation.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the sensor film is made thinner to fit narrow gaps, then adaptability to brake system geometry is improved, but the film's mechanical strength decreases

Engineering Contradiction:
Improvegap accommodationVSAvoidfilm strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The sensor film utilizes composite material construction combining flexible polymer substrates with piezoelectric sensing layers. This composite structure achieves the necessary thinness for fitting narrow gaps while maintaining adequate mechanical strength through the combined properties of the composite layers, including the magnetic adhesive film for secure attachment.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The flexible sensor film is designed with sufficient thinness to accommodate narrow gaps in the brake system while maintaining structural integrity through careful material selection and magnetic reinforcement. The magnetic adhesive film provides additional strength for secure attachment without increasing the overall thickness significantly.

Inventive Principle:
Principle #30Flexible shells and thin films

4Device complexity

If pneumatic pressure measurement is used to infer braking force, then device complexity is reduced, but measurement precision deteriorates due to indirect measurement

Engineering Contradiction:
Improvemeasurement system complexityVSAvoidbraking force measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The sensor film serves as a direct intermediary at the force transmission interface between brake pad and wheel, eliminating the need for indirect pneumatic pressure measurements. This direct contact measurement approach maintains relatively simple device structure while significantly improving measurement precision by capturing actual contact forces rather than inferring them from pressure changes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the pneumatic pressure measurement system with a direct mechanical force sensing film. This substitution eliminates the indirect measurement chain and associated errors, providing accurate braking force data while maintaining practical device simplicity through the use of flexible piezoelectric materials rather than complex mechanical force sensors.

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

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 precise and direct measurement of braking forces without altering the vehicle's braking system, reducing errors and allowing for quick, flexible deployment, while accommodating various surface conditions and narrow gaps, facilitating efficient maintenance and data transmission.

Implementation Method 1

a flexible sensor film for detecting a contact pressure of a brake pad or a brake shoe on a wheel or a brake disc of the vehicle

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The magnetic film can releasably attach the sensor film to metal parts, in particular to the curve of a brake pad or to a brake disc or to the wheel, using the magnetic adhesive force

Methodology Applied
Scientific EffectMagnetic adhesion: Magnetism

Data Source

PatentEP3722768B1Sensor device for detecting brake forces in a vehicle and measurement system
Publication Date: 2023.09.13 JOANNEUM RES FORSCHUNGS GMBH
  • EP3722768B1 patent drawingFigure 1~2
  • EP3722768B1 patent drawingFigure 3~4
  • EP3722768B1 patent drawingFigure 5

AI summary

Sensor device for detecting braking forces in a vehicle, comprising a flexible sensor film for detecting the contact pressure of a brake pad or brake shoe against a wheel or brake disc of the vehicle.