Gas sensor

Patent metadata

Field	Value
Publication number	US-2021132016-A1
Application number	US-202017075110-A
Country	US
Kind code	A1
Filing date	Oct 20, 2020
Priority date	Nov 5, 2019
Publication date	May 6, 2021
Grant date	—

Abstract

A gas sensor includes a gas sensor element for detecting the concentration of a specific gas in a gas under measurement, a tubular housing having an opening, a sealing member closing the opening, and a heat dissipating member having a rear end located at the same position or forward of the rear end of the housing. The heat dissipating member reduces heat transferred from the forward end side of the gas sensor to the sealing member and includes a connection portion connected to the housing, and a main portion extending rearward from the connection portion such that a gap is formed between the main portion and the housing. The main portion has heat dissipating openings for establishing communication between the gap and a space on the outer circumferential side of the heat dissipating member. The heat dissipating openings are formed on the rear end side of the main portion.

First claim

1 . A gas sensor extending in an axial direction from a forward end toward a rear end, the gas sensor comprising:
a gas sensor element that is configured to detect a concentration of a specific gas in a gas under measurement; a tubular housing surrounding the gas sensor element and having an opening at a rear end of the housing; a sealing member closing the opening; and a tubular heat dissipating member surrounding the housing and having a rear end located at the same position as the rear end of the housing or located forward of the rear end of the housing, the heat dissipating member reducing the amount of heat transferred from a forward end side of the gas sensor to the sealing member through the housing, wherein the heat dissipating member includes a connection portion connected to the housing on a forward end side of the sealing member, and a main portion extending rearward from the connection portion such that a gap is formed between the main portion and the housing, and the main portion has a heat dissipating opening that is configured to establish communication between the gap and a space on an outer circumferential side of the heat dissipating member, the heat dissipating opening being located rearward of the center of the main portion in the axial direction.

2 . A gas sensor extending in an axial direction from a forward end toward a rear end, the gas sensor comprising:
a gas sensor element that is configured to detect the concentration of a specific gas in a gas under measurement; a tubular housing surrounding the gas sensor element and having an opening at a rear end of the housing; a sealing member closing the opening; and a tubular heat dissipating member surrounding the housing and having a rear end located rearward of the rear end of the housing, the heat dissipating member reducing the amount of heat transferred from a forward end side of the gas sensor to the sealing member through the housing, wherein the heat dissipating member includes a connection portion connected to the housing on a forward end side of the sealing member, and a main portion extending rearward from the connection portion such that a gap is formed between the main portion and the housing, the main portion has a heat dissipating opening that is configured to establish communication between the gap and a space on an outer circumferential side of the heat dissipating member, and when a region where the main portion and the housing overlap each other is defined as an overlapping region, the heat dissipating opening is located rearward of the center of the overlapping region in the axial direction.

3 . The gas sensor according to claim 1 , wherein a length of the heat dissipating opening in the axial direction is greater than a half of a length of the heat dissipating member in the axial direction.

4 . The gas sensor according to claim 1 , wherein the heat dissipating opening gradually increases in width from the forward end side toward the rear end side.

5 . The gas sensor according to claim 1 , wherein the length of the heat dissipating opening in the axial direction is greater than a length of the heat dissipating opening in a direction perpendicular to the axial direction.

6 . The gas sensor according to claim 1 , wherein the housing includes:
a metallic shell surrounding the gas sensor element and having a polygonal tool engagement portion and a mounting portion disposed on the rear end side of the tool engagement portion to be continuous with the tool engagement portion; and an outer tube extending rearward from the metallic shell, surrounding the gas sensor element, and including a large diameter portion having a welded portion welded to the mounting portion together with the connection portion, a small diameter portion located rearward of the large diameter portion and being smaller in diameter than the large diameter portion, and a joining portion joining a rear end of the large diameter portion and a forward end of the small diameter portion, wherein a forward end of the heat dissipating opening is located rearward of the welded portion and is located forward of the joining portion.

7 . The gas sensor according to claim 1 , wherein, when the heat dissipating opening is viewed in a cross-sectional plane perpendicular to the axial direction,
a portion of the heat dissipating member on an outer side in a thickness direction thereof has a shape such that a distance between that portion and the widthwise center of the heat dissipating opening gradually decreases toward an inner side in the thickness direction, and a portion of the heat dissipating member on the inner side in the thickness direction has a shape that protrudes toward the inner side in the thickness direction.

8 . The gas sensor according to claim 1 , wherein the heat dissipating member has three or more heat dissipating openings formed such that the heat dissipating openings are arranged in a circumferential direction at equal intervals.

9 . The gas sensor according to claim 1 , wherein the heat dissipating member has an inward projecting portion projecting toward a radially inner side, and the inward projecting portion is in contact with the housing in a partial circumferential region.

Assignees

• Ngk Spark Plug Co

Inventors

• Matsuyama Daisuke
• Asai Masahiro
• Nomura Masashi
• Inose Yuto
• Oba Takehiro

Classifications

• G01N33/0009 Primary

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

• G01N33/0016 Primary

  by regulating a physical variable, e.g. pressure or temperature · CPC title