Sensor

Patent metadata

Field	Value
Publication number	US-10371680-B2
Application number	US-201715414808-A
Country	US
Kind code	B2
Filing date	Jan 25, 2017
Priority date	Jan 25, 2016
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

A gas sensor is provided with a metal shell protecting member formed of a material superior in heat resistance to a metal shell, whereby a high-temperature measurement target (exhaust gas) is prevented from being in direct contact with a region, of a protector internal region of the metal shell, on the front side relative to a protector opposing surface. That is, in the gas sensor, it is possible to suppress corrosion, due to high temperature, of a region, of the protector internal region of the metal shell, on the front side relative to the protector opposing surface (an inner surface and a front end surface of a protector fixing portion), while the metal shell is formed of a material (SUS430) that can be subjected to working (crimping or the like) accompanied with deformation. Therefore, heat resistance of the entire sensor can be improved.

First claim

The invention claimed is:

1. A sensor comprising:
a sensor element that is formed in an elongated shape extending in an axial direction, and includes a detection portion at a front side thereof;
a metal shell that is formed in a tubular shape having a through-hole extending from a front-side opening thereof to a rear-side opening thereof, and holds the sensor element via an element holding member, the sensor element being disposed in the through-hole, with the detection portion projecting from the front-side opening;
a tubular element protector that includes an opening, through which a measurement target passes, and is fixed to a front side of the metal shell, and
a metal shell protecting member, wherein
the metal shell includes, at an outer surface thereof, a protector opposing surface that opposes a rear end portion of the element protector,
the metal shell protecting member is configured to cover, together with the element protector, at least a part of a front end surface of the metal shell, at least a part of an inner surface of the through-hole, and at least a part of a radial outer surface of the metal shell, which is connected with the front end surface of the metal shell, and
wherein the metal shell protecting member is formed of a material having corrosion resistance higher than that of the metal shell.

2. The sensor according to claim 1 , wherein
when a protector internal region is defined to include: a region of an inner surface of the through-hole of the metal shell, which is provided on the front side relative to the element holding member; a region of the radial outer surface of the metal shell, which is covered with the element protector; and the front end surface of the metal shell,
the metal shell protecting member and the element protector cover at least a region of the protector internal region of the metal shell, which is provided on the front side relative to the protector opposing surface.

3. The sensor according to claim 1 , wherein the metal shell protecting member is formed in a tubular shape having an insertion hole through which the sensor element is inserted.

4. The sensor according to claim 1 , wherein the metal shell protecting member includes a protector contact portion that is in contact with an inner surface of the element protector over a circumferential direction.

5. The sensor according to claim 1 , wherein an inward projecting portion that projects inward is provided at a rear side of the metal shell protecting member.

6. The sensor according to claim 1 , wherein the metal shell protecting member is formed of a metal material.

7. The sensor according to claim 1 , wherein the metal shell protecting member covers a region, of the inner surface of the through-hole, on the front side relative to the element holding member, and is in contact with the element holding member.

8. The sensor according to claim 7 , wherein
the element holding member includes: a ceramic holder that is in contact with the sensor element; and a metal holder that is disposed outward relative to the ceramic holder and is in contact with the metal shell, and
the metal shell protecting member covers a region of the inner surface of the through-hole, which is provided on the front side relative to the element holding member, and is in contact with at least one of the ceramic holder and the metal holder.

9. A sensor comprising:
a sensor element that is formed in an elongated shape extending in an axial direction, and includes a detection portion at a front side thereof;
a metal shell that is formed in a tubular shape having a through-hole extending from a front-side opening thereof to a rear-side opening thereof, and holds the sensor element via an element holding member, the sensor element being disposed in the through-hole, with the detection portion projecting from the front-side opening;
a tubular element protector that includes an opening, through which a measurement target passes, and is fixed to a front side of the metal shell, and
a metal shell protecting member, wherein
the metal shell includes, at an outer surface thereof, a protector opposing surface that opposes a rear end portion of the element protector, and
the metal shell protecting member is configured to cover, together with the element protector, at least a part of a front end surface of the metal shell, at least a part of an inner surface of the through-hole, and at least a part of a radial outer surface of the metal shell, which is connected with the front end surface of the metal shell, and
the metal shell protecting member is formed of a material superior in heat resistance to the metal shell.

10. A sensor comprising:
a sensor element that is formed in an elongated shape extending in an axial direction, and includes a detection portion at a front side thereof;
a metal shell that is formed in a tubular shape having a through-hole extending from a front-side opening thereof to a rear-side opening thereof, and holds the sensor element via an element holding member, the sensor element being disposed in the through-hole, with the detection portion projecting from the front-side opening;
a tubular element protector that includes an opening, through which a measurement target passes, and is fixed to a front side of the metal shell, and
a metal shell protecting member, wherein
the metal shell includes, at an outer surface thereof, a protector opposing surface that opposes a rear end portion of the element protector,
the metal shell protecting member is configured to cover, together with the element protector, at least a part of a front end surface of the metal shell, at least a part of an inner surface of the through-hole, and at least a part of a radial outer surface of the metal shell, which is connected with the front end surface of the metal shell, and
the detection portion protrudes through a front end of the metal shell protecting member in the axial direction.

11. The sensor according to claim 10 , wherein the radial outer surface of the metal shell is covered by the element protector.

Assignees

• Ngk Spark Plug Co

Inventors

• Kume Makoto
• Ito Shingo
• Oba Takehiro
• Miyamoto Shinya
• KYOUMOTO Suguru

Classifications

• G01N27/407

  for investigating or analysing gases {(G01N27/411 takes precedence)} · CPC title

• G01N33/0009

  General constructional details of gas analysers, e.g. portable test equipment (devices for withdrawing samples in the gaseous state G01N1/22) · CPC title

• G01N27/4077 Primary

  Means for protecting the electrolyte or the electrodes · CPC title

• G01N33/0036 Primary

  specially adapted to detect a particular component (physical analysis of gaseous biological material G01N33/497) · CPC title