Ngk Spark Plug Company, Limited

Hitoshi Iimi

Takahiro Hayashi

Yoshiaki Matsubara

Yasuhiro Fujita

Masataka Taguchi

A gas sensor comprises a cylindrical metallic housing, a sensor element having at a front end thereof a sensing portion and disposed axially in the housing with the sensing portion protruded from a front end of the housing, a sensor terminal fitted to a rear end of the sensor element to produce a signal output from the sensing portion, a first protective cover attached to a front end portion of the housing to cover the sensing portion and a second protective cover attached to a rear end portion of the housing to cover the sensor terminal. The first and second protective covers includes attachment portions attached around the front and rear end portions of the housing, respectively. At least one of the attachment portions of the first and second protective covers has a lower hardness than a remaining portion of the protective cover.

Protective covers for gas sensor, gas sensor and gas sensor manufacturing method

It is an object of the invention to provide a sensor which is highly reliable, and a method or producing a sensor which is highly reliable, and which can be easily produced. A method of producing a sensor in which bending of a heater and the like hardly occur is provided. In the invention, an oxygen sensor () has: an oxygen sensor element (); a metal shell (); first and second sensor terminal metal parts (), (); a heater (); heater terminal metal parts (), (); a metal outer tube (); and a separator () which is housed inside the metal outer tube (), in which the terminal metal part () and the like and the heater () are held, and which provides insulation between the terminal metal part () and the like. An outer-tube butting face () is formed in a flange portion () of the separator (). In the metal outer tube (), a flange butting face () which butts against the outer-tube butting face () is formed. Both of the outer-tube butting face () and the flange butting face () form an inclined face which is more radially outward positioned as further advancing toward the tip end. The separator () is pressed toward the rear end. The pressing is conducted by deforming the metal outer tube (), and deforming a pressing metal part () which is placed around a tip end side portion () of the separator ().

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Aichi, Japan

Hitoshi Iimi