Sensor

Patent metadata

Field	Value
Publication number	US-2018275083-A1
Application number	US-201815935413-A
Country	US
Kind code	A1
Filing date	Mar 26, 2018
Priority date	Mar 27, 2017
Publication date	Sep 27, 2018
Grant date	—

Abstract

One object is to increase the amount of abrasion powder accumulated in a sensing region to improve the sensitivity in sensing the abrasion powder. Provided is a sensor for sensing reduction of electric resistance between electrodes, a magnetic field being applied between the electrodes to accumulate magnetic powder floating in a lubricant between the electrodes, wherein at least one sensing region in which the magnetic powder is to be accumulated is provided in at least a part of a region between the electrodes, and the magnetic powder is inhibited from being accumulated in a non-sensing region constituted by a space around the electrodes other than the at least one sensing region.

First claim

What is claimed is:

1 . A sensor for sensing reduction of electric resistance between electrodes, a magnetic field being applied between the electrodes to accumulate magnetic powder floating in a lubricant between the electrodes,
wherein at least one sensing region in which the magnetic powder is to be accumulated is provided in at least a part of a region between the electrodes, and the magnetic powder is inhibited from being accumulated in a non-sensing region constituted by a space around the electrodes other than the at least one sensing region.

2 . The sensor of claim 1 , wherein the electrodes include:
a first electrode; and at least one second electrode, wherein at least one gap is provided between the first electrode and the at least one second electrode, and the at least one gap includes the at least one sensing region to which the magnetic field is applied.

3 . The sensor of claim 2 , wherein the first electrode comprises a magnet producing the magnetic field.

4 . The sensor of claim 2 , further comprising a magnet producing the magnetic field.

5 . The sensor of claim 3 , further comprising a covering member that covers the electrodes to inhibit the magnetic powder from being accumulated in the non-sensing region.

6 . The sensor of claim 3 , wherein an entire periphery of the magnet is covered with a magnet covering member.

7 . The sensor of claim 3 , wherein the magnetic field is selectively applied to the at least one sensing region.

8 . The sensor of claim 3 , wherein the at least one sensing region comprises a plurality of sensing regions.

9 . The sensor of claim 8 , wherein
the plurality of sensing regions comprise a first sensing region and a second sensing region, the first sensing region is provided adjacent to an N-pole of the magnet, and the second sensing region is provided adjacent to an S-pole of the magnet.

10 . The sensor of claim 8 , wherein
the at least one second electrode comprises a plurality of second electrodes, the at least one gap comprises a plurality of gaps provided between the first electrode and each of the plurality of second electrodes, and each of the plurality of gaps includes one of the plurality of sensing regions.

11 . The sensor of claim 10 , wherein the plurality of sensing regions have different gap lengths.

12 . The sensor of claim 8 , comprising a plurality of pairs of the first and second electrodes,
wherein the plurality of pairs of the first and second electrodes have different gap lengths.

13 . The sensor of claim 3 , wherein
a narrow recess is provided in an outer periphery of the sensor, and the at least one sensing region is provided deep in the recess.

14 . The sensor of claim 3 , further comprising a filter member disposed between the at least one sensing region and an outer space, the filter member blocking foreign matter having a large particle diameter.

15 . The sensor of claim 3 , configured such that magnetic flux is prevented from leaking out of the at least one sensing region.

16 . The sensor of claim 15 , wherein
the at least one sensing region is interposed between
a first plane formed on the first electrode and
a second plane formed on the at least one second electrode and opposed in parallel to the first plane, and
the magnetic flux intersects the first plane and the second plane perpendicularly in the at least one sensing region.

Assignees

• Nabtesco Corp

Inventors

• Kiriyama Takeshi
• Nishimura Takeshi
• Sakurai Kazuhiko
• Harada Masaki

Classifications

• G01N27/12 Primary

  of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid {, for detecting components in the fluid} · CPC title

• G01N33/2858 Primary

  Metal particles · CPC title

• G01N27/06 Primary

  of a liquid (involving electrolysis G01N27/26) · CPC title