Ferrite Plastic Road Marker for Oxidation-Resistant Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional magnetic markers using neodymium magnets are susceptible to oxidation, requiring airtight metallic cases, increasing costs and size, which in turn raises installation costs.

Innovation Solution

A magnetic marker composed of a sintered magnet made from iron oxide magnetic powder dispersed in a polymer material, eliminating the need for a sealed structure and allowing for a smaller, more cost-effective design with a columnar shape that can be easily integrated into a road surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a neodymium magnet is used to generate a strong magnetic field, then the magnetic field strength is improved, but the magnet becomes susceptible to oxidation requiring airtight metallic cases, increasing cost and size

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidoxidation resistance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent replaces expensive, oxidation-prone neodymium magnets with a cost-effective alternative using iron oxide magnetic powder dispersed in polymer material. This disposable-style approach uses simpler, cheaper materials that don't require protective housing, eliminating the need for airtight metallic cases while maintaining functional adequacy for vehicle sensor detection.

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

Solution Approach 2:

The patent creates a composite magnetic marker by dispersing iron oxide magnetic powder within a polymer material matrix. This composite structure provides both magnetic functionality and inherent protection against oxidation, as the polymer encapsulation prevents direct exposure of the magnetic powder to environmental factors, eliminating the need for separate metallic protective cases.

Inventive Principle:
Principle #40Composite materials

2Power

If a neodymium magnet with airtight metallic case is used, then the magnetic field strength is improved, but the size and installation cost increase

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidmarker size
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The patent adopts a simplified, disposable-style magnetic marker design using iron oxide powder in polymer material, eliminating the need for bulky metallic protective cases. This reduces the overall size of the magnetic marker while maintaining sufficient magnetic field strength for vehicle sensor detection, thereby reducing installation complexity and cost.

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

Solution Approach 2:

The composite structure of iron oxide magnetic powder dispersed in polymer material provides a compact, integrated solution where the polymer matrix serves both as a structural medium and as protection for the magnetic particles. This eliminates the need for additional metallic housing, reducing the overall volume of the magnetic marker compared to conventional designs with separate protective cases.

Inventive Principle:
Principle #40Composite materials

3Power

If a neodymium magnet with airtight metallic case is used, then the magnetic field strength is improved, but the production cost increases

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidproduction cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent employs a cost-effective magnetic marker design using iron oxide magnetic powder and polymer material, replacing expensive neodymium magnets and metallic protective cases. This approach significantly reduces material costs and simplifies manufacturing processes, making the magnetic marker more economically viable while maintaining adequate performance for drive assist applications.

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

Solution Approach 2:

The composite formulation of iron oxide magnetic powder dispersed in polymer material offers a low-cost alternative to conventional neodymium magnets with metallic housing. The polymer-based composite can be manufactured through simpler processes such as mixing and molding, reducing both material and processing costs compared to the assembly of metallic cases with internal magnets.

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 reduces production and installation costs while maintaining magnetic field strength, allowing for reliable detection by vehicle sensors and improved durability against environmental factors.

Implementation Method 1

a magnetic marker that is a magnet molded into a columnar shape and contains a magnetic powder that is a powder of a magnetic material

Methodology Applied
Scientific EffectMagnetic field generation: Magnetism

Data Source

PatentEP3473770B1Magnetic marker and marker system
Publication Date: 2022.10.19 AICHI STEEL CORP
  • EP3473770B1 patent drawingFigure 1
  • EP3473770B1 patent drawingFigure 2
  • EP3473770B1 patent drawingFigure 3

AI summary

A magnetic marker (1), laid in or on a road so as be detectable by a magnetic sensor (2) attached to a bottom surface side of a vehicle (5), that is used for vehicle-side drive assist control for assisting driving is an isotropic ferrite plastic magnet, molded into a columnar shape, that contains a magnetic powder of iron oxide, i.e. a powder of a magnetic material, dispersed in a polymer material. In a marker system (1S) including this magnetic marker (1), magnetic markers (1) accommodated in holes (530) bored in a road surface (53) are arranged along the center of a lane.