US Patent 7467538 Gas sensor and method for manufacturing the same

A gas sensor and method of producing the same, the gas sensor including a sensor element extending along a longitudinal axis of the gas sensor; a metal shell surrounding the sensor element; and a protector fixed on a front portion of the metal shell and covering a front portion of the sensor element which projects from the front end of the metal shell, wherein an oil agent is present on one or both of an inner gas-receiving surface of the metal shell and an inner peripheral surface of the protector in a total amount of less than 0.7 mg.