Ngk Spark Plug Company, Limited

Primearth Ev Energy Co., Ltd.

Nobuaki Sakayanagi

Katsutoshi Nakayama

Tomoaki Kato

Shigeki Saito

Shinya Mitsuda

Ryuichi Ono

A laser welding device that laser-welds a lid to an open portion of a casing emits a laser beam to a joining subject portion including an inner side surface of the casing that defines the open portion and a peripheral surface of the lid that faces the inner side surface of the casing. The inner side surface of the casing and the peripheral surface of the lid are arranged to form a groove in between, and include inclined surfaces that function as a sliding portion. The groove portion has a groove width that is variable by sliding the sliding portion. A detection unit detects the groove width of the groove portion. An adjustment force application unit applies force for adjusting the groove width to the casing. A control unit controls the force applied by the adjustment force application unit in accordance with the groove width detected by the detection unit.

Laser welding device, laser welding method, and battery casing

A spark plug includes an insulator; a center electrode; a metallic shell; a ground electrode disposed at a forward end portion of the metallic shell and forming a gap in cooperation with a forward end portion of the center electrode; and a tip at least a portion of which is joined to at least the one of two side surfaces of the ground electrode which is disposed downstream with respect to fuel gas flow. In a first imaginary plane which contains a forward end surface of the center electrode and on which a discharge surface of the tip is projected, at least a portion of a projected image of the discharge surface is located within a range of 2.5G from the outer circumference of the forward end surface of the center electrode, where G (mm) is the size of the gap.

Spark plug

A spark plug includes: a rod-shaped center electrode extending in an axial direction; an insulator including a shaft hole that holds the center electrode inside of the shaft hole; a metal shell surrounding and holding a part of the insulator; and a ground electrode including a base end welded to the metal shell. The metal shell and the ground electrode are joined via a fusion portion formed by welding the ground electrode and the metal shell together. When the smallest thickness of the fusion portion in the axial direction is A, when, in a cross section that includes a center line of the ground electrode and is parallel to the axis, a length of a ground-electrode-side melted boundary formed between the fusion portion and the ground electrode is B, and when the ground electrode thickness is C, conditions of A&#x2267;0.2 mm and B&#x3e;C are satisfied.

Spark plug and method of manufacturing the same

In a spark plug, a fusion zone where a ground electrode and a noble metal tip are fused together is formed in at least a portion of an interfacial region between the ground electrode and the noble metal tip. When the fusion zone is projected in the axial direction, the projected fusion zone overlaps 70% or more of the area of the noble metal tip. As viewed on a section which passes through the center of gravity of the noble metal tip and is perpendicular to the longitudinal direction of the ground electrode, the relational expression 1.3&#x2266;B/A is satisfied, where A is the greatest thickness of the fusion zone along the axial direction, and B is the length from a portion having the greatest thickness of the fusion zone to the inner end of the fusion zone.

Spark plug with improved resistance to spark-induced erosion of the ground electrode tip

A spark plug includes a tubular insulator, a center electrode, a tubular metal shell, a ground electrode, and a pillar body tip. The tubular insulator has an axial hole penetrating in the direction of an axis. The pillar body tip includes one end face that is welded to the ground electrode and another end face that forms a gap with a front end portion of the center electrode. The ground electrode includes a part where the tip is to be welded. The surface forms a clearance with a part including a constituent material of the tip. The ground electrode includes a surface where a plating layer is disposed. The plating layer covers a surface excluding a formation part of the clearance. The clearance has a size A that is equal to or more than 0.01 mm and equal to or less than 0.5 mm.

A method for improving welding strength between a ground electrode and a noble metal tip on a spark plug. A fusion zone is formed along at least a portion of the boundary between the ground electrode and the noble metal tip through fusion of a portion of the ground electrode and a portion of the noble metal tip.

A method of manufacturing a spark plug having an insulator, a center electrode, a metallic shell, a ground electrode, and a noble metal tip provided on the ground electrode and having a discharge surface forming a spark discharge gap in cooperation with the center electrode. The method of manufacturing includes a fusion-zone formation step of forming a fusion zone through radiation of a high-energy beam to the boundary between the ground electrode and the noble metal tip.

Method of manufacturing sparkplugs

A spark plug () including a noble metal tip joined to a ground electrode and forming a spark discharge gap in cooperation with a center electrode. A surface of the noble metal tip which forms the gap has an area of 0.9 mmor greater. The noble metal tip () is joined to the ground electrode () via a fusion zone () formed by irradiating at least one surface among a distal end surface and side surfaces of the ground electrode with a laser beam or an electron beam. Further, as viewed on a projection plane orthogonal to a center axis of the noble metal tip and on which the noble metal tip and the fusion zone are projected along the center axis, an overlapping region between the noble metal tip () and the fusion zone accounts for 70% or more of a projected region of the noble metal tip.

Separation of a noble metal tip is prevented and wear resistance is enhanced, while the increase in manufacturing cost is suppressed. A spark plugincludes a center electrodeand a noble metal tip. The center electrodeand the noble metal tipare joined to each other through a molten portion. An area of an interface between the noble metal tipand the center electrodeis set to be 5% or less with respect to a cross-sectional area of the noble metal tipwhich is perpendicular to an axial line CLat a portion of an outer surface of the noble metal tipwhich is nearest to the molten portion. In the cross section including the axial line CL, supposing that a length of the portion of the molten portionin the axial line CLwhich is exposed to the outer surface is A (mm), and a width of the noble metal tipis B (mm), B/A&#x2266;6 is satisfied. The portion of the molten portion, of which a length along the axial line CLis A/1.5, is located further outwards radially than a position which comes in by as much as B/4 from the outer circumference of the noble metal tip

Peeling resistance of a noble metal chip is improved by reducing a difference in the thermal stress generated between the noble metal chip and a ground electrode. A spark plugincludes an insulator, a center electrode, a metal shell, and a ground electrode, wherein a spark discharge gapis formed between the center electrodeand the noble metal chipbonded to the ground electrode. The ground electrodeis provided with a concave hole portion, and 70% or more of the noble metal chipis bonded to the hole portionof the ground electrodethrough a fusion portionformed by fusing the noble metal chip and the ground electrodeto each other by emitting a laser beam or the like from the side surface of the noble metal chip. A gapis formed between the noble metal chipand at least a part of an inner wall surfaceS of the hole portionso as to be more than 0 mm and equal to or less than 1.0 mm in the direction perpendicular to the central axis CLof the noble metal chip

A spark plug includes an insulator, a center electrode, a metal shell, a ground electrode, and a noble metal tip joined to at least one of the two electrodes. The noble metal tip is joined to the electrode via a melt portion formed by using a laser or electron beam from a side surface of the noble metal tip. In a predetermined section, including a central axis of the noble metal tip, &#xbe; or more of one end face of the noble metal tip is joined to the electrode. When the thickness of the melt portion is taken to be TX (mm), and the length in a direction of irradiation with the laser beam is taken to be LX (mm), TX and LX satisfy 1.5&#x2266;LX/TX, and an angle &#x3b1;X or angle &#x3b1;Y, formed by two predetermined straight lines, satisfies &#x2212;15&#x2266;&#x3b1;X (&#x3b1;Y)&#x2266;25.

Growing community of inventors

Toyohashi, Japan

Nobuaki Sakayanagi