Spring Oriented RFID Board Antenna Fatigue

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Solution Overview

Problem

RFID devices integrated into tires face antenna fatigue failure due to mechanical stress from flexing and rotation, leading to separation or breakage of the antenna from the electronics, which existing designs fail to adequately address.

Innovation Solution

An RFID device with a printed circuit board featuring asymmetric arms and a helically wound antenna element, surrounded by a non-conductive elastomeric material, creating a controlled stress gradient to enhance antenna connection resilience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the antenna is adhered to the tire rubber or electronics, then the RFID device can be integrated into the tire, but the antenna may separate from the electronics due to cracking, breaking, or fatigue from tire flexing

Engineering Contradiction:
Improveantenna connection reliabilityVSAvoidantenna connection strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a flexible printed circuit board (FPCB) as the antenna substrate instead of rigid PCB or direct adhesion to tire rubber. The FPCB can bend and flex with the tire deformation, preventing cracking and connection failure while maintaining electrical connectivity between the antenna and electronics throughout the tire's service life

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs a composite structure combining FPCB material with antenna conductive traces and solder joints. This composite design integrates the flexibility of the FPCB substrate with the electrical conductivity of the antenna traces, creating a unified structure that withstands mechanical stress while maintaining electrical functionality

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If the wire and connected circuit move or rotate relative to one another, then the RFID device can accommodate tire motion, but the wire may incur concentration of mechanical stress and fatigue at the connection point

Engineering Contradiction:
Improvetire motion accommodationVSAvoidconnection point reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent transforms the static rigid connection into a dynamic flexible connection using FPCB technology. The FPCB can dynamically adapt its shape and bend radius according to tire deformation, distributing mechanical stress along the flexible circuit traces rather than concentrating it at fixed connection points, thereby maintaining reliability during tire motion

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the physical state and mechanical properties of the connection medium from rigid to flexible. By using FPCB with specific flexural rigidity and elastic properties, the system can accommodate varying degrees of tire deformation while maintaining connection integrity, effectively adapting to different motion conditions

Inventive Principle:
Principle #35Parameter changes

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 significantly improves antenna fatigue resistance by precisely locating reinforcement and using elastomeric material to distribute stress evenly, reducing the likelihood of antenna separation and breakage.

Implementation Method 1

creating a controlled stress gradient to enhance antenna connection resilience

Methodology Applied
Scientific EffectStress gradient:

Implementation Method 2

surrounded by a non-conductive elastomeric material, creating a controlled stress gradient

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

using elastomeric material to distribute stress evenly

Methodology Applied
Scientific EffectStress distribution:

Implementation Method 4

surrounded by a non-conductive elastomeric material

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP2611631B1Spring oriented RFID board
Publication Date: 2016.07.20 MICHELIN RECH & TECH SA
  • EP2611631B1 patent drawingFigure 1~3

AI summary

Disclosed is an apparatus for providing an RFID device for integration into a tire. A printed circuit board (PCB) is provided with a pair of asymmetric arms forming notches in opposed ends of the PCB. Helically wound antenna elements are positioned in the notches such that the ends of the asymmetric arms are positioned adjacent the nearest approach of the individual helically wound antenna elements.