Patent ID: 6682639
Filing Date: 2004-01-27
Classification: G01N

Abstract:
A gas sensor comprising:a sensor element having at a tip end portion thereof a detecting section for detecting a component of a gas to be measured; a casing accommodating therewithin the sensor element and having an open end portion from which the detecting section protrudes; and a cup-shaped protector attached to the open end portion of the housing for covering the detecting section; the protector being dual-walled and having cup-shaped inner and outer protector members; the outer protector member having at the circumferential wall thereof a plurality of first gas holes; the inner protector member having at the circumferential wall thereof a plurality of second gas holes; when the direction of the tip end portion of the sensor element is referenced to as forward, the first gas holes being disposed forward of the second gas holes; a front end of the sensor element being disposed forward of the second gas holes; the inner and outer protector members having circumferential walls between which a predetermined space of the distance g1 is defined so that an exhaust gas is caused to flow rearward from the first gas holes through the space of the distance g1 to the second gas holes and forward within the space around the detecting section; the inner and outer protector members having at bottom walls thereof bottom gas holes for allowing an exhaust gas introduced through the second gas holes into the inner protector member to be discharged from the inner protector member through said bottom gas holes; and the bottom wall of the outer protector member and the bottom wall of the inner protector member being welded together.