Abstract: A gas sensing element and related manufacturing method are disclosed with a solid electrolyte body having one surface formed with a measuring-gas-side electrode and the other surface formed with a reference-gas-side electrode, wherein a measuring-gas-side lead portion is formed on the solid electrolyte body in connection with the measuring-gas-side electrode and a reference-gas-side lead portion is formed on the solid electrolyte body in connection with the reference-gas-side electrode. A dense protective layer is formed on the solid electrolyte body so as to cover the measuring-gas-side lead portion, and a porous protective layer is laminated on the dense protective layer so as to cover the measuring-gas-side electrode, wherein the relationship is established as QB?0.8 QA where QB represents a porosity rate of a base end region of the measuring-gas-side lead portion in an area spaced from the base end of the dense protective layer by a distance of approximately 0.

Abstract: A gas sensor includes a sensor element and a porcelain insulator in which the sensor element is retained. The sensor element includes a measurement gas electrode, an electric lead extending from the measurement gas electrode, a dense protective layer covering the lead, and a porous protective layer disposed on the dense protective layer to cover the measurement gas electrode. The dense protective layer protrudes from an end of the porous protective layer by a distance of 5 mm or less, thereby ensuring the mechanical strength of the porous protective layer to minimize physical separation of the lead from the solid electrolyte layer. The base end of the porous protective layer lies inside porcelain insulator, thereby covering the whole of a portion of the sensor element exposed directly to the measurement gas with the porous protective layer to minimize the separation of the lead.

Abstract: A gas sensing element includes a solid electrolytic substrate having oxygen ion conductivity, a measured gas side electrode provided on a surface of the solid electrolytic substrate so as to be exposed to a measured gas, and a reference gas side electrode provided on another surface of the solid electrolytic substrate so as to be exposed to a reference gas. The measured gas side electrode is covered by a porous electrode protecting layer. A limit current density of the electrode protecting layer is in a range from 0.04 mA/mm2 to 0.15 mA/mm2 on a unit area of the reference gas side electrode.

Abstract: A contact slidable structure is formed between a resilient terminal and a terminal electrode. The terminal electrodes and are disposed on the ceramic element. The resilient terminals and are resiliently deformed and forced to press the terminal electrodes and. The ceramic element has the ceramic body, inner leads and formed inside the ceramic body, terminal electrodes and disposed on the outer surfaces and, and conductive through holes and electrically connecting the inner leads and with the terminal electrodes and, respectively. In the ceramic element, the resilient terminals and are placed slidably on the outer surfaces and of the terminal electrodes and to form the contact slidable structure, and the conductive through holes and are not formed within the contact slidable areas and to the terminal electrodes and, respectively.

Abstract: A gas sensing element is placed in an element insertion hole of an insulator. The element insertion hole consists of a larger-diameter portion and a smaller-diameter portion. A clearance between an inner surface of the larger-diameter portion and an outer surface of the gas sensing element is filled with a sealing material. A clearance between an inner surface of the smaller-diameter portion and the outer surface of the gas sensing element is filled with a cushion filler having the capability of withstanding a loading force ranging from 5N to 1,000N.

Abstract: In a gas sensor element, a sensor portion has a solid electrolyte member and a pair of electrodes. The solid electrolyte member has first and second surfaces opposite thereto. The first and second electrodes are mounted on the first and second surfaces of the solid electrolyte member, respectively. A heater member has a heating element and one and other surfaces opposite thereto. The sensor portion is integrally laminated on the one surface of the heater member. The other surface of the heater member is contactable to the target gas. At least a part of the other surface of the heater member has a ten points average roughness that is no more than 1.71 &mgr;m.

Abstract: A contact slidable structure is formed between a resilient terminal and a terminal electrode. The terminal electrodes and are disposed on the ceramic element. The resilient terminals and are resiliently deformed and forced to press the terminal electrodes and. The ceramic element has the ceramic body, inner leads and formed inside the ceramic body, terminal electrodes and disposed on the outer surfaces and, and conductive through holes and electrically connecting the inner leads and with the terminal electrodes and, respectively. In the ceramic element, the resilient terminals and are placed slidably on the outer surfaces and of the terminal electrodes and to form the contact slidable structure, and the conductive through holes and are not formed within the contact slidable areas and to the terminal electrodes and, respectively.

Abstract: A gas sensing element includes a solid electrolytic substrate having oxygen ion conductivity, a measured gas side electrode provided on a surface of the solid electrolytic substrate so as to be exposed to a measured gas, and a reference gas side electrode provided on another surface of the solid electrolytic substrate so as to be exposed to a reference gas. The measured gas side electrode is covered by a porous electrode protecting layer. A limit current density of the electrode protecting layer is in a range from 0.04 mA/mm2 to 0.15 mA/mm2 on a unit area of the reference gas side electrode.

Abstract: A gas sensing element is placed in an element insertion hole of an insulator. The element insertion hole consists of a larger-diameter portion and a smaller-diameter portion. A clearance between an inner surface of the larger-diameter portion and an outer surface of the gas sensing element is filled with a sealing material. A clearance between an inner surface of the smaller-diameter portion and the outer surface of the gas sensing element is filled with a cushion filler having strength of 5N to 1,000N.