Abstract: A method of producing a spark plug comprises (a) a step of combining a metallic shell and an insulator; (b) a step of inserting a portion of the assembly on its forward end side into a pressure container; (c) a step of bringing an insulating member into contact with the outer circumferential surface of a base side portion of the insulator over the entire circumference thereof, and pressing the assembly so as to close the opening by the assembly; and (d) a step of pressurizing the interior of the pressure container and applying a predetermined voltage between the terminal electrode and the metallic shell.

Abstract: A method of producing a spark plug comprises (a) a step of combining a metallic shell and an insulator; (b) a step of inserting a portion of the assembly on its forward end side into a pressure container; (c) a step of bringing an insulating member into contact with the outer circumferential surface of a base side portion of the insulator over the entire circumference thereof, and pressing the assembly so as to close the opening by the assembly; and (d) a step of pressurizing the interior of the pressure container and applying a predetermined voltage between the terminal electrode and the metallic shell.

Abstract: A method of producing a spark plug comprises (a) a step of combining a metallic shell and an insulator; (b) a step of inserting a portion of the assembly on its forward end side into a pressure container; (c) a step of bringing an insulating member into contact with the outer circumferential surface of a base side portion of the insulator over the entire circumference thereof, and pressing the assembly so as to close the opening by the assembly; and (d) a step of pressurizing the interior of the pressure container and applying a predetermined voltage between the terminal electrode and the metallic shell, wherein the step (b) includes a step of inserting the portion of the assembly on the forward end side into the pressure container such that a gap formed between the outer surface of the insulator and the inner surface of the metallic shell on the forward end side of the assembly is disposed in the pressure container.

Abstract: A method for producing a spark plug, including an inspection step for an insulator includes: (a) a step of preparing an assembly; (b) a step of attaching the assembly to a pressure vessel; (c) a step of attaching an insulating member to the assembly so as to cover at least a part of a surface of a portion of the insulator that is exposed at the rear side; and (d) a step of pressurizing an interior of the pressure vessel and applying a predetermined voltage between the metal terminal and the metal shell. The producing method further includes a step of adhering a lubricant to at least one of a surface of the insulator and an inner surface of the insulating member.

Abstract: A method of producing a spark plug comprises (a) a step of combining a metallic shell and an insulator; (b) a step of inserting a portion of the assembly on its forward end side into a pressure container; (c) a step of bringing an insulating member into contact with the outer circumferential surface of a base side portion of the insulator over the entire circumference thereof, and pressing the assembly so as to close the opening by the assembly; and (d) a step of pressurizing the interior of the pressure container and applying a predetermined voltage between the terminal electrode and the metallic shell, wherein the step (b) includes a step of inserting the portion of the assembly on the forward end side into the pressure container such that a gap formed between the outer surface of the insulator and the inner surface of the metallic shell on the forward end side of the assembly is disposed in the pressure container.

Abstract: A method for producing a spark plug, including an inspection step for an insulator includes: (a) a step of preparing an assembly; (b) a step of attaching the assembly to a pressure vessel; (c) a step of attaching an insulating member to the assembly so as to cover at least a part of a surface of a portion of the insulator that is exposed at the rear side; and (d) a step of pressurizing an interior of the pressure vessel and applying a predetermined voltage between the metal terminal and the metal shell. The producing method further includes a step of adhering a lubricant to at least one of a surface of the insulator and an inner surface of the insulating member.