US Patent 7524407 Gas sensor

An oxygen sensor 10 includes an oxygen detection element 20, which assumes a hollow tubular shape extending along the axis. The oxygen detection element 20 has a closed tip end and an opened rear end. An internal electrode layer 23 is formed on an inner circumferential surface 22 of the oxygen detection element 20. The sensor 10 also has a terminal member 30 which is in contact with the internal electrode layer 23 and in electrical connection therewith. The terminal member 30 has press contact portions 34c and 34d which come into press contact with the inner circumferential surface 22 of the oxygen detection element 20 to hold the terminal member 30 in the oxygen detection element 20, and conduction portions 35b which come into press contact with the internal electrode layer 23 on the inner circumferential surface 22 of the oxygen detection element 20 and into electrical connection with the internal electrode layer 23. Pressing force per unit area at the conduction portions 35b is smaller than that at the press contact portions 34c and 34d.