Magnetic marker and marker system

Patent metadata

Field	Value
Publication number	US-10801170-B2
Application number	US-201716309990-A
Country	US
Kind code	B2
Filing date	Jun 13, 2017
Priority date	Jun 17, 2016
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

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 ( 1 S) 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.

First claim

The invention claimed is:

1. A marker system, comprising:
a plurality of types of magnetic markers having different ratios of height to a size of a cross-section, the plurality of types of the magnetic markers including at least a sheet magnetic marker disposed on a surface of a road, or a columnar magnetic marker inserted in the road so as to be detectable by a magnetic sensor of a vehicle and used for vehicle-side drive assist control for assisting driving, wherein
each of the plurality of types of the magnetic markers includes a magnet that contains a magnetic powder that is a powder of a magnetic material, and
each of the different ratios of the magnetic markers is changed according to either a thickness of an asphalt layer constituting a road surface or traffic volume.

2. The marker system according to claim 1 , wherein the magnetic marker is a magnet having a magnetic flux density of 45 mT or lower of a surface thereof.

3. The marker system according to claim 2 , wherein the magnet is provided with a retaining structure for preventing the magnetic marker from being removed in a pull-out direction when accommodated in a hole.

4. The marker system according to claim 1 , wherein the magnetic powder is a magnetic powder of iron oxide.

5. The marker system according to claim 4 , wherein the magnet is a molded article having the magnetic powder dispersed in a polymer material constituting a base material.

6. The marker system according to claim 5 , wherein the polymer material is asphalt.

7. The marker system according to claim 1 , wherein the magnet is a molded article having the magnetic powder dispersed in a polymer material constituting a base material.

8. The marker system according to claim 7 , wherein the polymer material is asphalt.

9. The marker system according to claim 1 , wherein the magnetic marker is a columnar magnet measuring 50 mm or smaller in diameter.

10. The marker system according to claim 1 , wherein the magnet is provided with a retaining structure for preventing the magnetic marker from being removed in a pull-out direction when accommodated in a hole.

11. The marker system according to claim 1 , wherein the magnetic marker has an outer circumferential surface all or a part of which is formed by a protective layer including at least fiber.

12. The marker system according to claim 1 , wherein the magnet holds an information providing part that provides a vehicle side with information by radio communication.

13. The marker system according to claim 12 , wherein the information providing part provides the vehicle side with height-indicating information by radio communication.

14. The marker system according to claim 1 , wherein the columnar magnetic marker is laid in a state of being accommodated in a hole bored in a road surface.

15. The marker system according to claim 14 , wherein the columnar magnetic marker is accommodated in the hole in a state of being recessed from the road surface, and a lid is fitted in the hole.

16. The marker system according to claim 15 , wherein the lid is a lid made of a paving material.

17. The marker system according to claim 15 , wherein the lid is a lid made of metal or resin and is fitted in the hole so as to serve as a mark for a laying place of the magnetic marker.

18. A marker system, comprising:
a plurality of types of magnetic markers, including at least a sheet magnetic marker disposed on a surface of a road, and a columnar magnetic marker inserted in the road, so as to be detectable by a magnetic sensor of a vehicle and used for vehicle-side drive assist control for assisting driving, wherein
each of the plurality of types of the magnetic markers includes a magnet that contains a magnetic powder that is a powder of a magnetic material, and
the plurality of types of the magnetic marker are combined so as to be different in ratio of height to a size of a cross-section and in magnetic flux density of a surface thereof and so as to be equal in magnetic flux density at an upper-limit height in a possible range of heights of attachment of the magnetic sensor in the vehicle.

19. A marker system, comprising:
a plurality of types of magnetic markers, including at least a sheet magnetic marker disposed on a surface of a road, or a columnar magnetic marker inserted in the road, so as to be detectable by a magnetic sensor of a vehicle and used for vehicle-side drive assist control for assisting driving, wherein
the sheet magnetic marker includes a magnet formed into a sheet shape and containing a magnetic powder that is a powder of a magnetic material,
the columnar magnetic marker includes a magnet molded into a columnar shape and containing a magnetic powder that is a powder of a magnetic material,
the sheet magnetic marker is disposed on the surface of the road of a detour temporarily set to avoid entry of the vehicle into a region into which entry is temporarily restricted or a guidepath temporarily set so as to guide the vehicle, and
the columnar magnetic marker is permanently inserted in the road.

20. The marker system according to claim 19 , wherein the sheet magnetic marker that is disposed on the surface of the road of the detour or guidepath temporarily set and the columnar magnetic marker that is permanently inserted in the road have different polarities so as to be distinguishable on a vehicle side.

Assignees

• Aichi Steel Corp

Inventors

• Yamamoto Michiharu
• Nagao Tomohiko
• Aoyama Hitoshi

Classifications

• G08G1/042

  using inductive or magnetic detectors · CPC title

• E01F9/30 Primary

  Arrangements interacting with transmitters or receivers otherwise than by visible means, e.g. using radar reflectors or radio transmitters (E01F11/00 takes precedence) · CPC title

• E01F11/00 Primary

  {Road engineering aspects of} Embedding pads or other sensitive devices in paving or other road surfaces {, e.g. traffic detectors, vehicle-operated pressure-sensitive actuators, devices for monitoring atmospheric or road conditions}(pressure-sensitive elements G01L; traffic control systems G08G) · CPC title

• G05D2201/0213

  Physics · mapped topic

• G05D1/02

  Control of position or course in two dimensions · CPC title