Brake Pad Piezoceramic Sensor Protection Under Heat and Pressure

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Solution Overview

Problem

Existing sensorized braking devices for vehicles are vulnerable to high temperatures and mechanical stresses, leading to performance issues, reliability concerns, and reduced durability, especially when operating above 200°C and 400 kg/cm², which affects the accuracy and longevity of piezoceramic sensors.

Innovation Solution

A sensorized braking device with a support element, a block of friction material, and piezoceramic sensors, where each sensor is embedded within a protective element made of resin-based material with stable mechanical properties between -40°C and 200°C, providing thermal and electrical insulation, and directing external compression forces to minimize stress on the sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If piezoceramic sensors are used to detect mechanical stresses in braking devices, then measurement precision is improved, but reliability deteriorates due to vulnerability to high temperatures and mechanical stresses

Engineering Contradiction:
Improvedetection accuracy of mechanical stressesVSAvoidsensor durability under high temperature and pressure
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A protective element made of resin-based material is introduced as an intermediary between the piezoceramic sensor and the harsh environment (high temperature, high pressure). This protective element has stable mechanical properties across a wide temperature range (-40°C to 200°C) and provides thermal and electrical insulation, allowing the sensor to function reliably without direct exposure to extreme conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the thermal and mechanical parameters of the sensor system by embedding the piezoceramic sensor in a protective element with specific thermal insulation properties. This creates a thermal barrier that maintains the sensor operating temperature within acceptable limits even when the braking device experiences temperatures up to 200°C or higher.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the protective element is made thicker to improve thermal and mechanical protection, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesensor protection from thermal and mechanical stressVSAvoidstructural complexity of protective element
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protective element is made from resin-based composite materials that combine thermal insulation, mechanical protection, and electrical insulation properties in a single integrated structure. This multi-functional material approach provides comprehensive sensor protection without requiring multiple separate protective layers or complex structural designs.

Inventive Principle:
Principle #40Composite materials

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 solution ensures stable and accurate mechanical stress detection by piezoceramic sensors across varying temperatures, enhancing the device's robustness and flexibility for use in light, industrial, and heavy vehicles, while maintaining sensor integrity and performance.

Implementation Method 1

one or more piezoceramic sensors supported by the support element and interposed between the block of friction material and the metallic support element... the piezoceramic sensors detect the forces that are exchanged

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

said protective element having one or more layers of resin-based material applied to protect said piezoceramic sensor, said resin-based material being electrically and thermally insulating

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3303869B1Braking device for vehicles
Publication Date: 2021.01.20 ITT ITAL SRL
  • EP3303869B1 patent drawingFigure 1
  • EP3303869B1 patent drawingFigure 2~4
  • EP3303869B1 patent drawingFigure 5~6

AI summary

The braking device for vehicles, comprising a support element (2) supporting a block of friction material (3), an electrically insulated electrical circuit (9), and at least one piezoceramic sensor (4) interposed between the block of friction material (3) and the support element (2), the electrical circuit (9) being connected to the piezoceramic sensor (4) so as to pick up an electric response signal emitted by the piezoceramic sensor (4) when the braking device is subjected to an external compression force, and further comprising at least one protective element (16) having one or more layers of resin-based material applied to protect the piezoceramic sensor (4), said protective element (16) being configured to direct a predetermined part of said external compression force onto an area of the support element (2) surrounding the piezoceramic sensor (4), the resin-based material being selected from among materials having substantially stable mechanical properties in a temperature interval comprised between -40°C and at least 200°C, so as to limit or cancel out the variation in the response signal with the temperature variations to which said at least one piezoceramic sensor (4) is exposed in said temperature interval.