Patent ID: 7686932
Filing Date: 2010-03-30
Classification: G01N

Abstract:
1. A gas sensor comprising: a cylindrical metal shell; a detection element having a detection portion provided on a front end side thereof, the detection element being fixed inside the metal shell while the detection portion of the detection element protrudes from a front end side of the metal shell; and an element protection cap having ventholes, the element protection cap being fixed to the metal shell so that the detection portion of the detection element is covered with the element protection cap, the metal shell including an annular front-end-facing end surface provided in a front end region of the metal shell, and a crimping cylindrical portion extending to the front end side on an outer circumference of the front-end-facing end surface, the element protection cap including a protrusion portion which extends outward from a rear end side of the element protection cap and is received in the crimping cylindrical portion, the protrusion portion of the element protection cap being disposed in the crimping cylindrical portion while a metal ring packing is disposed so as to abut a front end facing surface of the protrusion portion, the crimping cylindrical portion being compressively deformed toward the front-end-facing end surface while being bent inward to cover the metal ring packing so that the protrusion portion of the element protection cap is pressed against the front-end-facing end surface through the metal ring packing thereby fixing the element protection cap to the metal shell, wherein: the protrusion portion of the element protection cap on which the metal ring packing abuts includes concave and convex portions provided outward along an outer circumferential direction, so that the metal ring packing is deformed and thereby interlocked with the concave and convex portions when the crimping cylindrical portion is compressively deformed; and the metal ring packing has a hardness lower than that of the element protection cap.