Abstract: A method for producing a spark plug is provided, which includes a ground electrode fixed to a housing, and a center electrode insulated electrically from the housing by an insulator, the ground electrode having a ground electrode base and a ground electrode section, which ground electrode section including an electrode base and a noble metal section. In order to produce the spark plug, the ground electrode base is connected to the ground electrode section, in which, in a first step, the electrode base is connected to the noble metal section to form the ground electrode section, and in a second step, the ground electrode section is connected to the ground electrode base.

Abstract: The invention describes a spark plug having an outer electrode (12), a central electrode (10), an inner conductor (2) connected to the central electrode (10) and an insulator (3) enclosing the inner conductor (2). It is provided according to the invention that the insulator (3) is produced by extrusion. The invention further relates to a method for production of a spark plug of that kind.

Abstract: A method and an apparatus for manufacturing a spark plug. A bending apparatus includes a bending unit having a preliminary bending unit and a main bending unit, and a gap adjusting unit. The main bending unit including pressing unit for pressing a distal end of a ground electrode toward a center electrode, and a gap adjusting unit configured to adjust a relative height position of the distal end of the ground electrode relative to a distal end of the center electrode in an axis line direction. The gap adjusting unit includes a gap adjusting unit for relatively moving the distal end of the ground electrode relative to the center electrode in a direction substantially perpendicular to the axis line direction, and a restricting unit for restricting relative movement of the distal end of the ground electrode relative to the center electrode in the axis direction.

Abstract: A spark plug includes an insulator having an axial hole extending in the direction of an axis, and a terminal electrode disposed at a rear end portion of the axial hole. An identifier bearing externally visible identification information is joined to the rear end surface of the terminal electrode. The identifier has a thickness of 0.03 mm or greater along the direction of the axis.

Abstract: There are provided a spark plug in which a plating film applied to a ground electrode can be relatively easily removed, without cost increase, to prevent deterioration in ignition performance, and a process for producing the spark plug. A spark plug 1 has a metal shell 3, a ground electrode 27 made of a Ni alloy and a Ni plating layer 28 containing Ni as a main component and applied to surfaces of at least a rear end portion of the ground electrode 27 and of the metal shell 3. A Ni plating film 41 applied to a center-electrode-side part of a portion of the ground electrode 27 to be bent has been irradiated with a laser beam or the like, thereby forming a molten layer 29 in which metal materials of the Ni plating film 41 and the ground electrode 27 are molten together on the center-electrode-side part of the portion of the ground electrode 27 to be bent. The Ni plating layer 28 is formed on a part of the ground electrode 27 other than the part irradiated with the laser beam.

Abstract: A manufacturing method for an ignition plug is provided. The method includes: preparing an insulator having a cavity provided at a leading end portion thereof by disposing a leading end of the center electrode more inwards than a leading end of the insulator; building the insulator in an interior of the metal shell such that the leading end of the insulator is situated closer to a rear end side than the leading end of the metal shell; removing at least part of a leading end portion of the metal shell which projects from a leading end face of the insulator; and disposing the ground electrode at the leading end portion of the metal shell and welding the ground electrode and the metal shell together after the removal step.

Abstract: A spark plug (1) 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 mm2 or greater. The noble metal tip (32) is joined to the ground electrode (27) via a fusion zone (35) 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 (32) and the fusion zone accounts for 70% or more of a projected region of the noble metal tip.

Abstract: A spark plug having sufficient durability for an internal combustion engine is provided by restraining a sharp increase in resistance of a resistor while the size of the spark plug is reduced. The spark plug comprises an insulator having an axial hole, a metallic shell provided on the outer circumference of the insulator, a center electrode inserted into a front end portion of the axial hole, a terminal electrode inserted into a rear end portion of the axial hole, and a ground electrode. A circular columnar resistor is disposed within the axial hole between the center electrode and the terminal electrode, thereby electrically connecting the center electrode and the terminal electrode. The resistor is composed of carbon black serving as a conductive material, a glass powder, and ceramic particles. The ceramic particles have a maximum particle size of 0.5 ?m or less.

Abstract: A spark plug having one or more electrodes at least partially fabricated from an aluminum-containing Ni-based alloy. The alloy is a volume-stable alloy that includes a Ni3Al precipitate in a ??-phase distributed in a Ni matrix ?-phase. The precipitate is formed in the alloy prior to the alloy being used to fabricate electrodes and thus prevents additional Ni3Al precipitate from being formed in the alloy once in service in a high-temperature environment. This, in turn, prevents a volume decrease of the alloy that may lead to an increased spark gap and spark plug malfunction. The volume-stable alloy may be made by solution treatment, quenching, and heat aging of a Ni—Cr—Al—Fe alloy.

Abstract: A spark plug and method of construction is provided, wherein the spark plug has a generally annular ceramic insulator and a metal shell surrounding at least a portion of the insulator. A ground electrode is operatively attached to the shell, wherein the ground electrode has a ground electrode sparking surface. The spark plug further includes a center electrode having an elongate body with a center electrode sparking surface. The sparking surface of the center electrode and the ground electrode sparking surface provide a spark gap. A brazed joint bonds at least one of the insulator to the shell or the center electrode to the insulator.

Abstract: A device for inspecting a spark plug insulator for bending, the spark plug insulator including a cylindrical body having a radially enlarged flange at an axially intermediate portion thereof, and a through hole formed in the body along an axial direction of the body. The inspection device includes an insulator supporting means for supporting the spark plug insulator so as to be slidable in an axial direction of the spark plug insulator, a linear inspection pin that is to be inserted into the through hole of the spark plug insulator supported by the insulator supporting means, and a detecting means for detecting a sliding movement of the spark plug insulator when the spark plug insulator is caused to slide in the axial direction thereof by the inspection pin by the inspection pin prevented from completely penetrating the through hole of the spark plug insulator owing to bending of the spark plug insulator which exceeds a predetermined tolerance.

Abstract: A method and apparatus to maximize spark plug life in pre-chamber spark plugs operating with ultra-lean mixtures and/or elevated engine BMEP is presented. Electrode erosion is reduced by spreading discharge energy over a wider surface area, maintaining fuel concentration in the spark gap, controlling gas static pressure during discharge, and maintaining safe electrode temperature. Energy is spread via a swirling effect created by periphery holes in an end cap, resulting in a lower specific energy discharge at the electrodes. Divergently configured electrodes reduce the spark voltage at high operating pressures and the energy required for ignition. The flow field generated at the electrodes prevents electrical shorts due to water condensation and avoids misfire. The center electrode insulation provides an effective heat transfer path to prevent electrode overheating and pre-ignition.

Abstract: A method for manufacturing a spark plug and a spark plug manufactured by the method in which a gasket used for securing the air-tightness when mounting the spark plug on an internal-combustion engine is prevented from falling out from the metal shell with a simple step.

Abstract: A method of manufacturing a spark plug includes the step of adjusting a spark gap in the spark plug. In the step, a ground electrode is repeatedly pressed, by a hammer, toward a center electrode. The hammer operates in a first mode when the size of the spark gap falls in a rough-process range which is above a predetermined value, and in a second mode when the size of the spark gap falls in a finish-process range which is between the predetermined value and a target value less than the predetermined value. The amount of pressing the ground electrode in any press stroke of the hammer in the second mode is less than that in any press stroke of the hammer in the first mode. The amount of pressing the ground electrode in every press stroke of the hammer in the second mode is equal to a fixed value.

Abstract: A method of producing a spark plug includes reducing the diameter of a center electrode while maintaining the heat dissipation property of the center electrode. A columnar member in which an outer skin member and a core member having a high thermal conductivity are clad, and which is columnarly extended, are configured by extrusion molding into a state where the thickness of the outer skin member is substantially uniform. A flange portion and a tip end portion are formed in the columnar member to obtain an electrode intermediate member. In a middle trunk portion of the electrode intermediate member, the thickness of the outer skin member is maintained. Then, the surface of the middle trunk portion is cut or polished to reduce the thickness, whereby the diameter of a center electrode is reduced while maintaining the outer diameter of the core member.

Abstract: A spark plug and method of manufacturing the same. The spark plug includes a tubular insulator holding a center electrode, and a tubular metallic shell holding the insulator. The insulator is inserted into the metallic shell from the rear end side thereof until a portion of the insulator engages the metallic shell. In this state, the circumferential edge of the rear end portion of the metallic shell is crimped, whereby the insulator is unitarily fixed to the metallic shell. A talc charged layer is formed in a clearance portion between the insulator and the metallic shell, and a wire packing is placed on a rear end portion of the talc charged layer for engaging the crimp portion. A portion of the talc charged layer is interposed between the wire packing and the rear trunk portion of the insulator.

Abstract: To provide a method of producing a spark plug in which a spark discharge gap with a suitable distance can easily be obtained without bending to deform a ground electrode in a direction in which the ground electrode moves towards or away from a metal tip of a center electrode, in the method of producing a spark plug, when a metal tip (a noble metal tip) 21 is welded to a front end portion 13a of a center electrode 13, the metal tip 21 is welded to the front end portion 13a of the center electrode 13 after a state is established in which the metal tip 21 alone is positioned in a radial direction where a predetermined spark discharge gap g is formed relative to a distal end portion 14b of a ground electrode 14 which is joined to a metal shell 11 at a proximal end portion 14a thereof.

Abstract: A spark plug for an internal combustion engine is provided which includes a hollow cylindrical metal shell with an open end portion to be exposed to a combustion chamber of the engine, a ground electrode joined to the metal shell, a center electrode disposed in the metal housing to define a spark gap between itself and the ground electrode. The spark plug also includes a stream shaper geometrically formed on an inner periphery of the open end portion of the metal shell to shape tumble vortexes of air-fuel mixture into vortex streams oriented toward a central portion of the combustion chamber. This ensures the stability of orientation of the tumble vortexes to control a flow of sparks, thereby enhancing the ignitability of the air-fuel mixture in the combustion chamber.

Abstract: A spark plug (20) includes a center electrode (24) and a ground electrode (22). The electrodes (22, 24) include a core (26) formed of a copper (Cu) alloy and a clad (28) formed of a nickel (Ni) alloy enrobing the core (26). The Cu alloy includes Cu in an amount of at least 98.5 weight percent, and at least one of Zr and Cr in an amount of at least 0.05 weight percent. The Cu alloy includes a matrix of the Cu and precipitates of the Zr and Cu dispersed in the Cu matrix. The Ni alloy of the clad (28) includes Ni in an amount of at least 90.0 weight percent. The Ni alloy also includes at least one of a Group 3 element, a Group 4 element, a Group 13 element, chromium (Cr), silicon (Si), and manganese (Mn) in a total amount sufficient to affect the strength of the Ni alloy.

Abstract: A spark plug having an integral gasoline combustion sensor is disclosed. The spark plug includes a center electrode assembly with a terminal stud at one end and a center electrode with a sparking surface at an opposite end; a generally tubular insulator surrounding the center electrode assembly; a shell surrounding the insulator and having along its length a turn-over on a first end, a barrel having an outer surface and barrel shoulder on a gasket flange thereof, a threaded portion, and a ground electrode; and a piezo sensor assembly located on the barrel shoulder proximate the outer surface of the barrel which includes a lower electrode contact, a piezo transducer, an upper electrode contact, an isolator having a convex upper surface, and an upper bushing which is attached to the barrel.

Abstract: A spark plug (20) includes at least one electrode(22, 24) having a sparking end (28, 32). The sparking end (28, 32) is formed of a high temperature performance alloy including chromium in an amount of 10.0 weight percent to 60.0 weight percent, palladium in an amount of 0.5 weight percent to 10.0 weight percent, and a balance substantially of at least one of molybdenum and tungsten. The sparking end (28, 32) presents a spark contact surface (36, 44), and at a temperature of at least 500° C., such as during use of the spark plug (20) in an internal combustion engine, a layer (50) of chromium oxide (Cr2O3) forms at said spark contact surface (36, 44). The layer (50) of Cr2O3 protects the bulk of the sparking end 32, 38 from the extreme conditions of the combustion chamber and prevents erosion, corrosion, and balling.

Abstract: A spark plug and manufacturing method. The spark plug (1) includes a metallic shell (3) extending along an axis CL1, a ceramic insulator (2), a center electrode (5), and a ground electrode (27) having a base end portion joined to a front end face (26) of the metallic shell (3). The method includes assembling the metallic shell (3) and a center electrode assembly (41); and joining the ground electrode (27) to the front end face (26). The distance between a reference plane SP perpendicular to the axis CL1 and the front end face (26) as measured along the axis CL1 varies in the circumferential direction. In the joining step, the position of the distal end portion of the ground electrode (27) relative to the front end portion of the center electrode assembly (41) along the axis CL1 is adjusted by changing the region of the front end face (26) to which the ground electrode (27) is joined.

Abstract: A sparkplug having ground and/or center electrodes that include a firing tip formed by reflowing of an end of wire having an opposite end carried by a feed mechanism. The present invention also includes methods of manufacturing an ignition device and electrodes therefore having a firing tip, including providing a metal electrode having a firing tip region; providing a wire having a free end and another end carried by a feed mechanism; and reflowing the free end to form a firing tip.

Abstract: A plasma jet spark plug and a manufacturing method therefor are disclosed. In a state in which a noble-metal chip having a flange-like outwardly projecting portion is disposed in a communication section of a ground electrode, an electrode base metal of the ground electrode is disposed in a stepped engagement portion of a metallic shell, which retains an insulator therein. While being pressed against a front end portion of the insulator, the noble-metal chip is joined to the electrode base metal, whereby a clearance between the ground electrode (electrode base metal) and the front end portion of the insulator can be closed. Therefore, energy of plasma generated within the cavity does not leak.

Abstract: A spark plug for an internal-combustion engine comprises an attachment fitting 2, an insulator 3, a center electrode 4 and an earth electrode 5 . While fixed to the attachment fitting 2, the earth electrode 5 has a convex part 510 formed by projecting toward the center electrode 4 a part of the opposed surface 51, which faces the center electrode 4, of the earth electrode and a concave part 520 formed toward the opposed surface 51 from the earth electrode's back surface 52 which is the reverse side of the opposed surface 51 of the earth electrode 5 . The convex part 510 is disposed so that the extension of a shaft center of the convex part 510 may pass through the area in which the concave part 520 is formed. A relation of S1>=s is realized when an area of an opening of the concave part 520 is set to S1 and an average cross-section area of a cross section of the convex part 510 perpendicular to an axial direction of the spark plug is set to s.

Abstract: A spark plug and method for making. The spark plug comprises a center electrode, an insulator surrounding the center electrode, and a metallic shell surrounding the insulator. The spark plug also includes a ground electrode engaged with the metallic shell. The ground electrode has a first surface facing the center electrode for defining a spark gap and a second surface opposite the first surface. A cross-section of the ground electrode between the first and second surfaces includes a first zone of a non-noble metallic base material extending a distance from the second surface toward the first surface and a second zone of a blend of the non-noble base material and a noble metallic material extending from the first zone to the first surface. A method of making the spark plug includes the step of disposing a quantity of noble metallic material on an electrode blank formed of a non-noble metallic base material.

Abstract: A spark plug including a center electrode and a ground electrode. A center electrode noble metal tip is joined to a leading end portion of a center electrode, and a ground electrode noble metal tip is joined to a center-electrode-side side surface of the ground electrode. A distal end portion of the ground electrode noble metal tip protrudes from a distal-end surface of the ground electrode by 0.1 mm to 1.5 mm. A center-electrode-side side surface of the ground electrode noble metal tip projects from a center-electrode-side side surface by 0.15 mm to 0.6 mm. The ground electrode includes chamfered portions. Thickness lengths and widthwise lengths of the respective chamfered portions achieved within a cross section perpendicular to a center axis of the ground electrode are set to 0.2 mm or more.

Abstract: A spark plug in which an ignition portion of a ground electrode formed through joining of a noble metal chip to the ground electrode has high durability, and a method of manufacturing the spark plug.

Abstract: A spark plug in which an ignition portion of a ground electrode formed through joining of a noble metal chip to the ground electrode has high durability, and a method of manufacturing the spark plug.

Abstract: A spark plug comprising: a center electrode extending along an axis; an insulator provided about the outer peripheral surface of the center electrode; a metal shell provided about the outer peripheral surface of the insulator; a noble metal tip provided at the leading end portion of the center electrode; one end of the ground electrode fixed at the leading end of the metal shell, and the other end of the ground electrode forming a gap with the leading end of the noble metal tip; a stopper preventing the noble metal tip from moving relative to the central electrode; a molten portion formed by irradiating laser or electron beam; and a closed space formed between the basal portion of the noble metal tip and the center electrode. The molten portion welds the center electrode and a part of the basal portion of the noble metal tip.

Abstract: A spark ignition device and method of construction is provided. The device includes a ceramic insulator and a metal shell surrounding at least a portion of the ceramic insulator. The metal shell extends along a central axis between an upper terminal end and a lower fastening end. The fastening end has a pair of projections diametrically opposite one another extending axially to free ends. A center electrode assembly is received at least in part in the ceramic insulator. In addition, the device includes an elongate ground electrode having opposite sides extending along a length of the ground electrode between opposite ends. The ground electrode has opposite faces with a sparking surface attached to one of the faces, wherein the face with the sparking surface attached thereto is sunk axially into the free ends of the projections with at least a portion of the opposite sides being surrounded by the projections.

Abstract: A decrease in yield and degradation of productivity can be avoided when a spark plug having an insulator with low mechanical strength is manufactured. In a second process, a terminal electrode 15 is inserted to a predetermined position in a state where an insulator 12 is heated to a temperature equal to or greater than the softening temperatures of first to third powder materials 16P, 17P, and 18P such that the first powder material 16P becomes a first conductive sealing material layer 16, the second powder material 17P becomes a resistor 17, and the third powder material 18P becomes a second conductive sealing material layer 18. In addition, a speed at which the terminal electrode 15 is inserted is reduced between the start and the end of the second process.

Abstract: A spark plug and method for making. The spark plug comprises a center electrode, an insulator surrounding the center electrode, and a metallic shell surrounding the insulator. The spark plug also includes a ground electrode engaged with the metallic shell. The ground electrode has a first surface facing the center electrode for defining a spark gap and a second surface opposite the first surface. A cross-section of the ground electrode between the first and second surfaces includes a first zone of a non-noble metallic base material extending a distance from the second surface toward the first surface and a second zone of a blend of the non-noble base material and a noble metallic material extending from the first zone to the first surface. A method of making the spark plug includes the step of disposing a quantity of noble metallic material on an electrode blank formed of a non-noble metallic base material.

Abstract: A spark plug for internal-combustion engines equipped with a center electrode and a ground electrode is provided. In the spark plug, the ground electrode is fixed to a mount fitting, while the ground electrode has a convex portion. The convex portion is made of a part of base materials of the ground electrode where the part is facing the center electrode, and is projected toward the center electrode. The convex portion has a fusion solidification part made of precious metal materials and a part of the base materials melted together and solidified at least on part of an electric discharge surface facing the center electrode.

Abstract: A spark plug and method of construction thereof is provided. The spark plug includes a metal shell having a through cavity, a lower insulator and a plastic upper insulator. The lower insulator is received in the through cavity and has a through passage with a center electrode received therein. A ground electrode is operatively attached to the shell in spaced relation from the ground electrode to provide a spark gap. The plastic upper insulator has a distal end received in the through cavity of the shell and a terminal end extending axially outwardly from the shell. The upper insulator has a through passage extending between the terminal end and the distal end. An elongate conductive member is received in the through passage of the upper insulator and is configured for electrical communication with the center electrode.

Abstract: A method for manufacturing a spark plug which includes: (a) preparing a metal shell; (b) preparing an insulator; (c) inserting the insulator in an insertion hole of the metal shell; (d) forming an intended crimping portion of the metal shell into a crimping portion; and (e) pressing a lower side portion of the metal shell closer to a position lower than the intended compressive deformation portion, and pressing the crimping portion of the metal shell in an axial direction to compressively deform the intended compressive deformation portion of the metal shell and thus seal a space between a stepped portion of the metal shell and a stepped portion of the insulator, wherein step (e) controls a pressing amount of a press in a constant value from the start of compressive deformation to the end thereof.

Abstract: A method of manufacturing a center electrode for a spark plug, the method including the steps of: resistance welding a sphere of a noble metal to a center electrode of a spark plug to provide a center electrode with an electrode tip that has a tip portion of a first configuration, the first configuration having a first height and a first width; and shaping the tip portion after the sphere is welded to the center electrode by a process wherein the tip portion will have a second configuration having a second height and a second width, the second height being greater than the first height and the second width being less than the first width wherein a peripheral edge of the noble metal is flush with a peripheral edge of the material it is secured to.

Abstract: Method and device for manufacturing a noble meal reinforced electrode for a spark plug. A base electrode element (1) is formed and positioned in a retaining attachment (2). A noble metal piece (3) is arranged by a suitable attachment (4) on the front side of the base electrode element (1), and pressed into the front side of the noble metal base element (1) by a press attachment, in particular a die (6), while the arrangement composed of the base electrode element (1) and noble metal piece (3) is preferably heated by an electric current. After cooling, subsequent pressing can be carried out, by which the noble metal piece (3) is pressed flat. It is also possible to weld together the noble metal piece (3) and the tip (7) of the base electrode element.

Abstract: A dual-electrode spark igniter (spark plug), which has two electrodes extending from the plug body. During a spark event, electricity flows across a first spark gap from a first electrode to a second electrode. Electricity also flows across a second spark gap from the second electrode to ground.

Abstract: An alumina-based sintered body for a spark plug having enhanced mechanical strength and a method of manufacturing the same, as well as a spark plug having the alumina-based sintered body for a spark plug and a method of manufacturing the same.

Abstract: A ground electrode and a metal shell are joined by welding or the like while an entire end face of a base of the ground electrode is brought into contact with a front end constituent face of the metal shell. The ground electrode has an extending portion extending forward in an axial (O) direction of the ground electrode. A front end portion faces a noble metal tip joined to a front end portion of the center electrode through a bending portion and forms a spark discharge gap (G) therebetween. A gap (a clearance) having a sufficient space to accommodate a virtual sphere (Q) with a radius of 1.2 mm is provided so that the virtual sphere (Q) being in contact with an inner face of the bending portion of the ground electrode is neither in contact with a center electrode nor an insulator.

Abstract: This invention has an object to provide a spark plug exhibiting high withstand voltage characteristics and high strength at high temperature, formed by an alumina-based sintered body prepared with excellent processability and high productivity, and a method for manufacturing the spark plug. This invention relates to a spark plug 1 including an insulator 3, wherein the insulator 3 includes a dense alumina-based sintered body having an average crystal particle diameter of 1.50 ?m or more, and the alumina-based sintered body contains Si, a Group 2 element component containing Ba and a Group 2 element other than those, and a rare earth element component, such that a ratio of a content S of the Si component to a total content of the content S and a content A of the Group 2 element component is 0.60 or more, and a method for manufacturing the spark plug 1 prepared through a grinding-shaping process in which the insulator 3 is ground before burning to shape the same.

Abstract: There is provided according to the present invention a manufacturing method of a spark plug that includes a cylindrical metal shell, a cylindrical ceramic insulator retained in the metal shell, a center electrode retained in the ceramic insulator and extending in an axial direction and a ground electrode having a rear end portion fixed to the metal shell and a front end portion formed with a protruding region facing a front end portion of the center electrode with a gap left therebetween and being of substantially uniform thickness except for an area where the protrusion is formed. The spark plug manufacturing method includes a press forming step for pressing the whole of a ground electrode material for constituting the ground electrode, so as to form a protruding region on a front end portion of the ground electrode material and a welding step for, after the press forming step, welding a rear end portion of the ground electrode material to the metal shell.

Abstract: A spark plug, center electrode and method of construction is provided. The spark plug has a generally annular ceramic insulator and a conductive shell surrounding at least a portion of the ceramic insulator. A ground electrode is operatively attached to the shell, with the ground electrode having a ground electrode sparking surface. A center electrode has an elongate body with a center electrode sparking surface. The center electrode sparking surface and the ground electrode sparking surface provide a spark gap. The center electrode body is constructed of a composite material including at least one ceramic material.

Abstract: A spark plug, a center electrode therefore and method of construction is provided. The spark plug has a generally annular ceramic insulator extending between a terminal end and a nose end. A conductive shell surrounds at least a portion of the ceramic insulator and a ground electrode having a ground electrode sparking surface is operatively attached to the shell. An elongate center electrode has a body extending between opposite ends, wherein the body is compacted and sintered of a conductive or semi-conductive ceramic material. One of the electrode ends provides a center electrode sparking surface to provide a spark gap between the center electrode sparking surface and the ground electrode sparking surface.

Abstract: A spark plug and method of construction is provided, wherein the spark plug has a generally annular ceramic insulator and a metal shell surrounding at least a portion of the insulator. A ground electrode is operatively attached to the shell, wherein the ground electrode has a ground electrode sparking surface. The spark plug further includes a center electrode having an elongate body with a center electrode sparking surface. The sparking surface of the center electrode and the ground electrode sparking surface provide a spark gap. A brazed joint bonds at least one of the insulator to the shell or the center electrode to the insulator.

Abstract: A process for forming a glass seal layer in a spark plug, comprising an inserting step of inserting a terminal electrode into an axial hole in an insulator, a hot compression step of pushing the terminal electrode in a heated state to thereby compress the glass powder mixture, and a cooling step of performing cooling to thereby form the glass seal layer.

Abstract: Exemplary embodiments of the present invention provide methods for forming spark plug insulators, particularly asymmetrical spark plug insulators, without required machining after an initial heating or firing of the spark plug insulator. In one exemplary embodiment, a method of forming an asymmetrical spark plug insulator is. The method includes: forming a first mixture comprising a binder formed of water and agar; forming a second mixture comprising a ceramic material; combining the first mixture and the second mixture to form a molding compound; injection molding the molding compound to form an asymmetrical spark plug insulator having a initial net shape and size; and sintering the asymmetrical spark plug insulator to cause hardening of the asymmetrical spark plug, the sintered asymmetrical spark plug having a final net shape and size.

Abstract: There is provided a method for producing a spark plug in which welding strength between a noble metal tip and an electrode joined by laser welding can be restrained from becoming weak. A noble metal tip (90) to be joined to a center electrode (2) or ground electrode of a spark plug to form a spark discharge gap is resistance-welded to each electrode containing no noble metal and then laser-welded. In the noble metal tip (90) exposed under a severe environment involving spark discharge, a molten portion (80) formed in such a manner that a portion of the noble metal tip (90) and a portion of the electrode are melted by laser welding and a non-molten portion (95) on the noble metal tip (90) side are apt to be peeled from each other in a boundary surface (83) between the molten portion (80) and the non-molten portion (95).

Abstract: In a wire drawing process for forming a wire rod containing iridium as a main component and which further contains nickel and at least one of platinum, rhodium and ruthenium, and having a cross-sectional area of not smaller than 0.05 mm2 and not larger than 1.2 mm2. The worked material is continuously heated red hot and/or white hot in a heating region 103 extending up to 60 mm from the work inserting surface 101a of a die 101 in a direction opposite that in which the work 102 moves, the work being heated to a temperature of 1000 to 1150° C. at a temperature measuring position 105 which is removed from the work inserting surface 101a by 20 mm. Furthermore, the temperature in the region 106 extending from the temperature measuring position 105 to the work inserting surface 101a is set to not lower than 1000° C., and the wire drawing rate is set to 300 to 1600 mm/min.