Patent ID: 6708551
Filing Date: 2004-03-23
Classification: G01N

Abstract:
A gas sensor comprising:a hollow cylindrical housing; a sensor element having a length which includes a sensing portion and a base portion, said sensor element being disposed within said housing with the sensing portion projecting from a front end of said housing and the base portion projecting from a rear end of said housing; a front cover installed on the front end of said housing to cover the sensing portion of said sensor element; a base cover installed on the rear end of said housing; a first hollow cylindrical porcelain insulator disposed within said base cover into which the base portion of said sensor element extends; a second hollow cylindrical porcelain insulator disposed in said housing, said second hollow cylindrical porcelain insulator being abutted to said first hollow cylindrical porcelain insulator in alignment with each other; contact members disposed within a chamber defined inside said first hollow cylindrical porcelain insulator, each of said contact members working to establish an electric contact between an electric terminal of said sensor element and a lead extending outside the gas sensor; and a positioning mechanism working to establish a given positional relation between said first and second hollow cylindrical porcelain insulators; and wherein said first hollow cylindrical porcelain insulator is in contact of a front end thereof with a rear end of said second hollow cylindrical porcelain insulator, and wherein said positioning mechanism is made up of a protrusion formed on one of the front end of said first hollow cylindrical porcelain insulator and the rear end of the second hollow cylindrical porcelain insulator and a recess formed in the other of the front end of said first hollow cylindrical porcelain insulator and the rear end of the second hollow cylindrical porcelain insulator, the protrusion being engaged in the recess.