WO2010041733A1 - スパークプラグ及びその製造方法 - Google Patents
スパークプラグ及びその製造方法 Download PDFInfo
- Publication number
- WO2010041733A1 WO2010041733A1 PCT/JP2009/067611 JP2009067611W WO2010041733A1 WO 2010041733 A1 WO2010041733 A1 WO 2010041733A1 JP 2009067611 W JP2009067611 W JP 2009067611W WO 2010041733 A1 WO2010041733 A1 WO 2010041733A1
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- WIPO (PCT)
- Prior art keywords
- tip
- center
- noble metal
- spark plug
- ground electrode
- Prior art date
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T21/00—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs
- H01T21/02—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs of sparking plugs
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
- H01T13/39—Selection of materials for electrodes
Definitions
- the present invention relates to a spark plug (ignition plug) for an internal combustion engine and a manufacturing method thereof.
- a noble metal tip (cylindrical body) is positioned and arranged through one end face at the center of the front end face of the center electrode base material (Ni or Ni alloy), and the outside of the joint face (part) of the two members. Generally, the periphery is melted and joined along the circumferential direction.
- the spark gap (dimension) is G, and at the base end of the ground electrode, the shortest distance between a line drawn parallel to the axis of the metal shell along the inner surface facing the center electrode and a bead by laser welding ( Assuming that (dimension) is A, depending on the diameter of the spark plug (the diameter of the mounting screw), G and A may satisfy A ⁇ 3G. Due to this, discharge (called abnormal discharge) may occur in this lateral gap other than the normal gap.
- the spark plug is used in a direct-injection engine with a biased atmosphere in the combustion chamber or an engine with a severe swirl (mixed airflow) condition, the base end (root) of the spark plug ground electrode is the mixed airflow.
- the inventor of the present application has advanced the research by paying attention to the fact that the abnormal discharge as described above occurs relatively in a spark plug having a center electrode in which a noble metal tip is fixed to a center electrode base material by welding.
- the abnormal discharge and side fire tend to occur between the bead part (the part where the molten metal solidifies in the welding) around the noble metal tip and the part near the base end of the ground electrode. I knew that there was.
- the end surface of the noble metal tip is positioned and arranged on the end surface of the center electrode base material and the outer peripheral edges of the joint surfaces (parts) of both members are laser-welded along the circumferential direction, both the sandwich surfaces are sandwiched.
- the outer peripheral edge of the member is melted and the molten metal is solidified, and the bead made of an alloy containing the metal composition of both members remains in the outer peripheral edge.
- a weld bead is very small in both width and height, but when viewed microscopically, the surface has irregularities and the electric field tends to concentrate.
- a metal oxide film is formed on the bead portion, which facilitates electron emission. For these reasons, the uneven portions are easy to discharge, and the inventor of the present application considered that this is the basic cause of inducing abnormal discharge.
- the inventor of the present application considers that the occurrence frequency of abnormal discharge is high when the convex portion faces the proximal end side of the ground electrode or is very close to the ground electrode when assembled as a spark plug. It was. Based on this inference, the present inventors conducted tests on a number of various samples in which the positional relationship of the convex portion with respect to the ground electrode, that is, the final end of the bead, was changed, and the result was as inferred. . In addition, the mechanism of generation
- the circumference of the welded portion is made to make one round along the circumferential direction of the noble metal tip. + ⁇ ) Welded around. That is, the end point in the circulating welding is not stopped at the welding start point which is the starting point, but is set to a position exceeding the start point by an appropriate amount in the circumferential direction.
- the bead is formed so that the final end of the bead is also superimposed on the bead at the welding start point that has already solidified after melting. On the other hand, no new bead is formed on the final end of the bead.
- the final end of the bead has a different surface form as compared with other bead portions on the circumference. Then, the aspect becomes apparent as an irregularly shaped protrusion or a raised convex portion that is higher in the radial direction than other bead portions.
- the occurrence of such a convex portion is not limited to continuous laser welding. That is, when welding along the circumferential direction with a pulse (oscillation) laser, pulse laser irradiation is performed sequentially at equal angular intervals along the circumferential direction so that some beads overlap from the welding start point. Is repeated a plurality of times to weld the outer peripheral edge of the joint surface of both members. At this time, a new bead is not formed on the bead at the final end formed by the last (end point) laser irradiation after the circulation. Thereby, even in the case of pulse laser welding, a convex portion is formed at the final end of the bead.
- the method of performing laser welding by turning around the joint surface between the center electrode base material and the noble metal tip one or more times along the circumferential direction is the case of using one laser welding machine (laser welding from one direction).
- the laser welding machine may be used.
- the center electrode base material is rotated by one or more rounds around its axis by rotating it half a turn (actually less than a half depending on the size of the welded part by one pulse). Laser welding is possible. For this reason, shortening of welding time and manufacturing efficiency are improved.
- a bead by each welding machine is formed separately, so that the final end of the bead (hereinafter also referred to as a termination or termination) exists at two opposing positions. It will be. Therefore, in this case, there are two relatively irregular protrusions or raised protrusions in the radial direction at the end of each bead.
- the axis of the center electrode base material when viewed along the axial direction from the tip side of the noble metal tip with three laser welders, the axis of the center electrode base material from three directions at positions at equal angular intervals of 120 degrees in the circumferential direction of the tip When laser welding is performed by making one or more rounds around the circumference, there are three convex portions at the end of each bead.
- a part of the bead is higher in the radial direction than the other end of the bead. It has been found that an upward convex part may be formed.
- the reason is as follows.
- a cylindrical noble metal tip is positioned concentrically and pressed against the tip of the center electrode base material having a larger diameter. Will be welded.
- a large error eccentric error
- the noble metal tip is unevenly distributed on the one side.
- the protrusions present in the form of irregularly shaped protrusions or swells that are higher in the radial direction than the other bead parts are located at the end of the bead.
- a convex part one or a plurality of convex parts; hereinafter referred to as a convex part of a bead or simply a convex part
- a noble metal tip are concentrically positioned and arranged at the tip of the center electrode base material.
- There is a convex portion generated due to a relatively large eccentricity error hereinafter also referred to as a convex portion due to an eccentricity error or simply a convex portion.
- a convex portion due to an eccentricity error or simply a convex portion.
- the present invention has been made based on such knowledge, and in a spark plug in which a noble metal tip is laser welded to a center electrode base material as a center electrode, occurrence of abnormal discharge other than a normal gap between the center electrode and the ground electrode
- the purpose is to reduce or prevent the deterioration of ignition performance.
- the invention according to claim 1 is a hollow shaft-shaped insulating member having a center electrode disposed at a tip, and a ground electrode that surrounds the insulating member and forms a spark gap with the center electrode.
- the center electrode is formed by welding a noble metal tip to the tip of a center electrode base material, and circulates around the joint surface between the center electrode base material and the noble metal tip one or more times along a circumferential direction.
- G is a spark gap between the center electrode and the ground electrode, At the base end of the ground electrode, when the shortest distance between a line drawn parallel to the axis X of the metal shell along the inner surface facing the center electrode and a bead by laser welding is A, G and A are in a dimensional relationship of A ⁇ 3G,
- the top of the convex portion formed relatively high in the radial direction should be on a straight line connecting the center of the noble metal tip and the center of the circumferential direction at the base end of the ground electrode. It is characterized by being located away from the straight line in the circumferential direction.
- the tip of the spark plug refers to the end of the spark plug itself in the axial direction (longitudinal direction) on which the center electrode or the ground electrode is provided.
- the term “tip” with respect to components and parts (or parts) also refers to the end that follows this.
- a typical example of the “noble metal tip” used for the electrode of the discharge part of the spark plug is a tip made of Pt (platinum) or Ir (iridium) alone or an alloy containing these as a main component.
- a third aspect of the present invention there are a plurality of the convex portions in the circumferential direction, and a portion of the interval in the circumferential direction formed by two convex portions having a maximum interval in the circumferential direction is a base end of the ground electrode. Facing each other, and the tops of the two convex portions are located in the circumferential direction away from a straight line connecting the center of the noble metal tip and the circumferential center at the base end of the ground electrode.
- a fourth aspect of the present invention when the spark plug is viewed along the axial direction from the tip side of the noble metal tip, Of the straight line connecting the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode, and the top of the convex portion formed relatively high in the radial direction among the beads by circulating laser welding, and the noble metal tip
- the invention according to claim 5 is the spark plug according to claim 4, wherein the angle ⁇ is maintained 90 degrees or more.
- the ground electrode extends forward from the tip of the metal shell, and a spark gap is formed between the tip of the noble metal tip forming the center electrode. 6.
- at least one of the corners formed by the inner surface facing the center electrode and each surface on both sides of the inner surface is provided on the ground electrode.
- the spark plug is characterized in that chamfering is given to a portion corresponding to the protruding length of the central electrode protruding in the axial direction from the tip of the member.
- the ground electrode extends from the tip of the metal shell to the front, and a spark gap is formed between the ground electrode and an outer peripheral surface of the noble metal tip forming the center electrode.
- the invention according to claim 9 is the invention according to claim 8, wherein at least one of the corners formed by an inner surface facing the center electrode and each surface on both sides of the inner surface is provided on the ground electrode.
- the spark plug is characterized in that chamfering is provided from a position in the axial direction corresponding to the tip of the member to the tip of the ground electrode itself.
- the invention according to claim 10 is the spark plug according to any one of claims 1 to 9, wherein a noble metal tip is laser-welded to the ground electrode.
- the invention according to claim 11 is the spark plug according to any one of claims 1 to 10, wherein the laser welding is pulsed laser welding.
- a constituent member such as a center electrode with a noble metal tip welded to the tip is inserted into a hollow shaft-like insulating member, and a constituent member such as a terminal electrode is disposed behind the center electrode. Fixing the constituent members such as the center electrode in the insulating member and assembling the insulating member assembly; The insulating member assembly in which the constituent members such as the center electrode are inserted and fixed is inserted from the rear end side of the metallic shell inside the cylindrical metallic shell provided with the ground electrode at its tip.
- the spark plug manufacturing method including a caulking step of caulking the metal shell and fixing the insulation member assembly inside the metal shell, the insulation member assembly inserted in the metal shell,
- the metal shell is positioned, Before the insulating member assembly is inserted into the metal shell, until the metal shell is swaged in the caulking step, The height in the radial direction of the bead is detected by the detecting means along the circumferential direction of the noble metal tip, and based on the detection data, the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode The position of the convex portion around the axis of the convex portion with respect to the straight line connecting the two is adjusted.
- a constituent member such as a center electrode with a noble metal tip welded to the tip is inserted into a hollow shaft-like insulating member, and a constituent member such as a terminal electrode is disposed behind the center electrode. Fixing the constituent members such as the center electrode in the insulating member and assembling the insulating member assembly; The insulating member assembly in which the constituent members such as the center electrode are inserted and fixed is inserted from the rear end side of the metallic shell inside the cylindrical metallic shell provided with the ground electrode at its tip.
- the spark plug manufacturing method including a caulking step of caulking the metal shell and fixing the insulation member assembly inside the metal shell, the insulation member assembly inserted in the metal shell,
- the metal shell is positioned, Before inserting the insulating member assembly into the metal shell, The height in the radial direction of the bead is detected by the detecting means along the circumferential direction of the noble metal tip, and based on the detection data, the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode The position around the axis of the top of the convex portion with respect to the straight line connecting the two is adjusted.
- the invention described in claim 14 is the spark plug manufacturing method according to claim 12 or 13, wherein the detecting means is based on image processing by camera photography.
- a fifteenth aspect of the invention is a spark plug manufacturing method according to the twelfth or thirteenth aspect of the invention, wherein the detection means is based on laser measurement.
- the final end part (end point part) of the bead is formed with an irregularly shaped protrusion or a high convex part due to bulging in the radial direction.
- the spark plug is viewed along the axial direction from the tip side of the noble metal tip, the top of the convex portion is on a straight line connecting the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode.
- the distance between the convex portion and the portion near the base end of the ground electrode is the shortest.
- the electric field tends to concentrate on the convex portion, and abnormal discharge tends to occur.
- the spark gap (dimension) is G, and at the base end of the ground electrode, the shortest distance between the line drawn parallel to the axis of the metal shell along the inner surface facing the center electrode and the bead by laser welding
- (dimension) is A
- G and A are in a dimensional relationship such that A ⁇ 3G, in particular, the swirl flow flows from the center electrode toward the base end side of the ground electrode.
- the spark plug according to the first aspect of the present invention has a dimensional relationship of A ⁇ 3G.
- the spark plug when the spark plug is viewed along the axial direction (the axial line of the plug) from the tip side of the noble metal tip, among the beads by the laser welding that circulates, the convex portion formed relatively high in the radial direction
- the top portion does not exist on a straight line connecting the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode, and is located away from the straight line in the circumferential direction. For this reason, the occurrence of abnormal discharge can be effectively prevented or reduced.
- the top of the convex portion which forms the final end of the bead and is relatively high in the radial direction, is located as far as possible from the straight line in the circumferential direction.
- Such a spark plug has an insulating member having a center electrode formed by welding a noble metal tip inserted into a main metal fitting having a cylindrical shape and a ground electrode at the tip, and the shaft is inserted from the tip side of the noble metal tip.
- the position of the top of the convex portion formed by the final end of the bead may be confirmed and assembled. That is, when viewed in this way, the top portion does not exist on a straight line connecting the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode, and is separated from the straight line in the circumferential direction. Make sure it is in position.
- the insulating member fixing the center electrode or the like in the main metal fitting is rotated by an appropriate angle around its axis, and the top of the convex portion which is the final end of the bead is not the base end side of the ground electrode, It is preferable to assemble the spark plug with the insulating member fixed to the metal shell, preferably facing the opposite side.
- a plurality of convex portions are formed by laser welding from a plurality of directions using a plurality of laser welding machines. For example, two of them are irradiated with laser from two directions at opposite positions in the circumferential direction, and the center electrode base material is rotated around the axis, for example, 135 degrees, and an appropriate number of pulse welding is performed in the rotation process.
- a bead portion formed relatively low in the radial direction between the two convex portions is formed on the noble metal tip. It is preferable to be on a straight line connecting the center and the center in the circumferential direction at the base end of the ground electrode.
- a bead portion formed relatively low in the radial direction between any two of the convex portions (preferably an intermediate portion or an intermediate portion in the circumferential direction of the two convex portions). However, it preferably exists on a straight line connecting the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode.
- the number of occurrences of the convex portion at the end of the bead varies depending on the number of laser welding directions, that is, the number of weld beads.
- the welding range (angular range in the circumferential direction) of each laser welder is basically the same.
- the circumferential length of the bead is generally a length obtained by dividing the outer circumference (one round) of the noble metal tip at equal angular intervals in accordance with the number of laser welding machines to be used. Therefore, the intervals in the circumferential direction of the convex portions at the end of the bead are substantially equal (angular intervals).
- the convex portion due to the eccentric error does not occur or can be ignored when the positioning accuracy is high. For this reason, when the convex portion due to the eccentricity error can be ignored and there are a plurality of convex portions at the end of the bead, as described in claim 2, the top portion of any convex portion is from the straight line. What is necessary is just to set the position by the positional relationship with the base end of the said ground electrode so that it may exist in the position away from the said circumferential direction.
- the convex portion due to the eccentric error is a problem that occurs regardless of the number of convex portions at the end of the bead and its position. For this reason, it may occur at a position where the two convex portions are close to each other regardless of whether the welding direction is one or plural.
- the circumferentially spaced portion formed by the two convex portions having the largest circumferential direction faces the proximal end side of the ground electrode.
- the tops of the two protrusions may be located away from the straight line connecting the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode.
- the part of the interval in the circumferential direction formed by the two protrusions having the maximum interval faces the proximal end side of the ground electrode, because the part of the interval is the center of the noble metal tip and the This includes the case where it exists on a straight line connecting the center in the circumferential direction at the base end of the ground electrode.
- the two apexes are located at substantially the same position or spaced apart at the same interval (angle) across the straight line from the straight line in the circumferential direction. preferable. That is, it is preferable that the intermediate portion between the two apexes be in a positional relationship through which the straight line passes.
- the top of the convex portion formed by the final end of the bead is maintained at an angle ⁇ of 45 degrees or more as described in claim 4, so that an effect of preventing abnormal discharge can be obtained.
- the angle ⁇ is maintained at 90 degrees or more, the occurrence thereof can be substantially eliminated.
- the spark plug according to the present invention is not limited to the spark plug having a spark gap between the tip surface of the noble metal tip forming the center electrode and the ground electrode, but also the noble metal tip forming the center electrode. It can also be embodied in the case between the outer peripheral surface and the ground electrode. And in these spark plugs, as described in claims 7 and 9, by giving chamfering to each corner of the ground electrode, there is no sharp corner (edge) at the corner, and accordingly, Since the occurrence of electric field concentration can be reduced, the effect of further reducing or preventing abnormal discharge is enhanced. In the spark plug described above, it is preferable that the noble metal tip is welded to the ground electrode base material to form the ground electrode from the viewpoint of improving the spark wear resistance.
- the enlarged view of the M section of FIG. The figure seen from the front end side explaining the welding process of the noble metal tip for center electrodes. Sectional drawing for description which provided chamfering to the inner surface side of the site
- the figure which added the convex part by eccentric error in FIG. Explanatory drawing of the process in which the convex part by an eccentric error is formed.
- the figure which added the convex part by an eccentric error in the enlarged view seen from the front end side which illustrates typically the welding bead at the time of laser-welding a center electrode base material and a noble metal tip from one direction.
- FIG. 1 is a semi-longitudinal sectional view for explaining the entire spark plug 101 and an enlarged view of the main part (tip part), and FIG. 2 is a further enlarged view of the main part (tip part). .
- a spark plug 101 of this example includes a hollow shaft-shaped ceramic insulating member 21 in which a center electrode 11 to which a noble metal tip 1 is welded is protruded from a tip 20, and the insulating member. 21 is configured as follows, with a cylindrical metal shell 41 having a ground electrode 51 at the tip 40 as a main body.
- the center electrode base material 10 is fixed by a seal glass 31 so as to protrude from the tip (lower end in FIG. 1) 20, and behind the seal glass 31 (see FIG. 1).
- the terminal electrode 35 is fixed through the resistor 33 with the rear end (upper end in FIG. 1) protruding from the rear end of the insulating member 21 through the seal glass 31b.
- the insulating member 21 (hereinafter also referred to as an insulating member assembly) 21 to which the center electrode 11 and the like are fixed is inserted into the metal shell 41 from the rear end side and assembled as a spark plug 101 as follows. It has been.
- the front-facing surface (annular step portion) 25 near the front end 20 of the insulating member (insulating member assembly) 21 is the rear-end facing surface (locking flange) formed at the front end portion inside the metal shell 41. ) 42 so as to be pressed through the packing 43.
- an O-ring 37 between the rear of the fixing flange 26 projecting on the outer periphery at the intermediate portion of the insulating member 21 and the inside of the large-diameter cylindrical portion behind the metal shell 41, A talc 38 and an O-ring 37 are interposed.
- the caulking cylindrical portion 45 at the rear end of the metal shell 41 is bent inward and compressed toward the front end side to be plastically deformed.
- the spark plug 101 is assembled by fixing the insulating member 21 with the center electrode 11 and the like fixed in the metal shell 41.
- a spark plug 101 is shown in the figure by applying a tool such as a plug wrench to the polygonal portion 47 for screwing through a mounting screw 46 provided on the outer peripheral surface near the tip of the metal shell 41. It is screwed into a plug hole (screw hole) of the cylinder head that is not to be mounted, and the ring flange portion 48 for seating is pressed against the seat surface of the cylinder head, and is attached to the cylinder head.
- the center electrode 11 is provided so that the tip of the center electrode 11 protrudes from the center of the tip 20 of the hollow shaft-shaped (cylindrical) ceramic insulating member 21.
- the center electrode 11 includes a cylindrical center electrode base material 10 disposed in the insulating member 21 except for a portion near the tip, and A columnar noble metal tip 1 (outer diameter ⁇ 0.6 mm, length 0.8 mm) welded to the tip surface 13 of the center electrode base material 10 and having a smaller diameter than the outer diameter ( ⁇ 2.0 mm) of the center electrode base material 10.
- the center electrode base material 10 although not shown, a copper alloy center shaft is disposed.
- the center electrode base material 10 and the ground electrode 51 are made of a Ni-based heat-resistant alloy such as Inconel 600 (trademark of Inconel) or a Fe-based heat-resistant alloy.
- the noble metal tip 1 is made of an alloy containing Pt or Ir as a main component, and is made of a conventionally known noble metal used for the spark plug 101.
- the ground electrode 51 is fixed to the tip 40 of the cylindrical metal shell 41 by welding.
- the ground electrode 51 extends from the distal end 40 of the metal shell 41 toward the front (downward in FIGS. 1 and 2) such that the portion near the base end (base) 52 is along the axis X of the metal shell 41 and the insulating member 21.
- a portion closer to the tip 55 is bent toward the center electrode 11 via the arc-shaped portion 53.
- a noble metal tip (disc) 57 welded to a surface of the distal end 55 of the ground electrode 51 that is continuous with the inner surface 56 facing the center electrode 11 side at the base end 52 is the noble metal tip 1 of the center electrode 11.
- the front end surface 3 and the regular gap G are formed (see FIGS. 2 and 5).
- the gap G is set to 0.7 mm to 1.3 mm.
- the ground electrode 51 has a rectangular cross-sectional shape, and has substantially the same cross-section from the base end (base) 52 to the tip. Further, when viewed from the front end 40 side of the metal shell 41, the long side 58 of the rectangle is arranged and fixed along the circumferential direction (tangential direction) at the front end (annular portion) 40 of the metal shell 41 (see FIG. 4). As shown in FIG.
- L1 and the shortest distance (distance) A (hereinafter also referred to as the lateral gap A) perpendicular to the axis X to the surface of the bead 6 welding the center electrode base material 10 and the noble metal tip 1 are dimensions of A ⁇ 3G. It is set to be a relationship. Specifically, A is set to 1.3 mm to 3.9 mm.
- the portion near the tip of the center electrode base material 10 has a diameter of 0.9 mm shown by a broken line in FIG. 5 via a truncated cone portion 10b formed in a tapered shape.
- the noble metal tip 1 is laser welded to the tip surface 13 of the cylindrical portion 10c.
- FIG. 5 shows the form after welding, and the peripheral surface of the cylindrical part 10c forms the bead 6 after melting.
- this welding positions and arrange
- the width of the bead 6 is in the range of 0.4 mm to 0.8 mm, and the depth is in the range of 0.1 mm to 0.3 mm.
- the height (maximum protrusion height) of the convex portion 7 as viewed from the tip 3 of the noble metal tip 1, that is, the amount H protruding radially outward from the other bead 6 portions is 0.03 mm to 0.00. It is about 2 mm.
- the convex portion 7 formed by the bead 6e at the final end (end point) is as follows when the spark plug 101 is viewed from the tip 3 side of the noble metal tip 1 along the axis X direction. Has been placed. That is, the straight line S1 connecting the center C1 (axis X) of the noble metal tip 1 and the center C2 in the circumferential direction (rectangular long side 58) at the base end 52 of the ground electrode 51, and the final end (end point) of the rotating bead 6 )
- the angle ⁇ formed by the straight line S2 connecting the top portion 8 of the convex portion 7 in 6e and the center C1 of the center electrode 11 (the noble metal tip 1) is disposed at a position of 90 degrees (see FIGS.
- the top 8 of the convex portion 7 at the final end (end point) 6e of the rotating bead 6 is the periphery of the center C1 of the center electrode 11 (noble metal tip 1) and the base end 52 of the ground electrode 51.
- the angle ⁇ from the straight line S1 in the circumferential direction is 90 degrees positively In a separate position.
- the top 8 of the convex portion 7 at the final end (end point) 6e of the rotating bead 6 is illustrated as being 90 degrees away from the straight line S1 in the circumferential direction. Even if the angle ⁇ is 45 degrees or 60 degrees or smaller than 90 degrees due to the dimensional relationship between the lateral gap A and the regular gap G based on the size and type of plug (the difference in the diameter of the mounting screw), the angle ⁇ is The effect of preventing the occurrence of abnormal discharge can be obtained by the amount applied. This is because of the normal gap (dimension) G, the line L1 drawn in parallel to the axis X at the base end 52 of the ground electrode 51 or the inner surface 56 near the base end 52, the center electrode base material 10 and the noble metal tip.
- the dimensional relationship with the shortest distance A perpendicular to the axis X to the surface of the bead 6 welding 1 varies depending on the type of spark plug or the screw size (mounting screw diameter). That is, when the diameter of the mounting screw 46 is relatively large, the dimension A itself is ensured to be relatively large. Therefore, even if the angle ⁇ is small, abnormal discharge is unlikely to occur. On the other hand, in a spark plug having a small mounting screw diameter, the lateral gap A is basically small and abnormal discharge is likely to occur.
- the angle ⁇ is set to a large value and set to 90 ° to 180 ° even from the point of reference for the assembly work of the spark plug. Is preferred.
- the spark plug 101 of this embodiment is obtained through the following assembly process.
- the insulating member is inserted by inserting the center electrode 11 or the like having the noble metal tip 1 welded to the tip into the insulating member 21 in the same manner as in the prior art. Assembled body. What is important is a check before the insulating member assembly is inserted into the metal shell 41 from the rear end side and the caulking cylindrical portion 45 at the rear end is caulked as described above.
- the top 8 of the convex portion 7 of the final end 6e of the bead 6 formed by welding the noble metal tip 1 is at a desired angle with respect to the base end 52 of the ground electrode 51 around the axis X.
- the end surface 5 of the noble metal tip 1 is positioned and arranged with respect to the front end surface 13 of the center electrode base material 10 as a part before being assembled to the insulating member 21, and the joining surface (part) of both members What is necessary is just to weld the outer periphery of this by the conventionally well-known laser welding method along the circumferential direction. That is, in this welding, as shown in FIG. 6, the outer peripheral edges of both members sandwiching the joint surface are irradiated with one pulse from the welding start point (point K on the upper right in FIG.
- pulse laser irradiation is repeated a plurality of times (eight in FIG. 6) at intervals of 45 degrees. And it goes around the outer periphery of the joint surface (part) of both members, and welds.
- the bead 6 reaches one round (360 degrees) + ⁇ degrees in the circumferential direction, that is, the bead by the first pulse laser irradiated around the K point is the eighth round (final start). ) So that the bead 6e by the pulse laser overlaps by the angle ⁇ when viewed from the axis X direction. By doing so, the bead 6e, which is the last-time (end-point) welded portion, is different from the other and the bead 6e is not formed on the bead 6e. Therefore, the final bead 6e has a spark plug 101 in the direction of the axis X from the tip 3 side of the noble metal tip 1, as schematically shown in FIG.
- convex portions (mountains) 7 that swell by H from the other side in the radial direction are inevitably formed.
- the position of the convex portion 7 is the final end portion of the bead.
- the bead by a pulse laser makes the top part 8 the center in the convex part 7 when it sees along an axis
- each sample of the spark plug 101 in which the angle ⁇ formed by the straight line S1 and the straight line S2 in FIGS. 4 and 6 is variously changed is prepared, one by one.
- the spark discharge test was carried out 100 times for each sample under an atmospheric pressure of 0.4 MPa. In this test, the number of occurrences of abnormal discharge (horizontal sparks) other than the normal gap G was measured to determine the rate of occurrence of lateral sparks, and the difference due to the angle ( ⁇ ) was confirmed.
- the ease of occurrence of abnormal discharge is fundamentally different. Therefore, four types of samples having different dimensional relationships were tested.
- the ground electrode 51 is preferably provided with the following configuration. This is because, in the above embodiment, the ground electrode 51 extends forward from the tip 40 of the metal shell 41, and a spark gap (regular gap) G is formed between the tip electrode 3 of the noble metal tip 1 that forms the center electrode 11. Thus, the tip 55 of itself is bent to the noble metal tip 1 side.
- a ground electrode 51 at least the tip of the insulating member 21 among the corners formed by the inner surface 56 facing the center electrode 11 and the surfaces 59, 59 on both sides of the inner surface 56 (see FIG. 7). It is preferable to chamfer 60 to a portion (region R in FIG.
- the chamfer 60 is not limited to the inclined chamfering and the rounded chamfering, and is preferably set as large as possible. Moreover, it is preferable to chamfer each corner as much as possible over a region (range) as long as the ground electrode 51 extends.
- the present invention is not limited to the contents described above, and can be embodied with appropriate modifications without departing from the scope of the invention.
- the case where the noble metal tip is welded to both the center electrode side and the ground electrode side has been described.
- the noble metal tip is welded only to the center electrode side. It can be widely applied to existing spark plugs.
- the ground electrode 51 extends forward from the tip 40 of the metal shell 41, and the spark gap G is formed between the tip electrode 3 and the tip surface 3 of the noble metal tip 1 forming the center electrode 11.
- the present invention has been described. However, the present invention is limited to such a spark gap configuration. is not.
- the ground electrode 51 extends forward from the tip 40 of the metal shell 41, and a spark gap G is formed between the outer peripheral surface 2 of the noble metal tip 1 that forms the center electrode 11.
- the present invention can also be embodied in an electrode structure in which its tip 55 is bent toward the noble metal tip 1 side. That is, in this spark plug 201, the ground electrode 51 extends from the front end 40 of the metal shell 41 to the front end of the base end 52 along the axis X direction, and the front end 55 passes through the intermediate arcuate portion 53. 11, the spark gap G is formed between the bent tip 55 of the ground electrode 51 and the outer peripheral surface 2 of the noble metal tip 1 forming the center electrode 11. It will be. In the example shown in the figure, the tip 55 of the ground electrode 51 is also welded with the noble metal tip 59.
- the center electrode 11 is composed of the center electrode base material 10 and the noble metal tip 1 welded to the tip thereof. Similar to the spark plug 101, there is a problem of abnormal discharge. It is apparent that the present invention is similarly effective in the structure of such a spark gap G. Also in this case, it is preferable to provide the chamfer 60 as described above at each corner formed by the inner surface 56 facing the center electrode 11 side of the ground electrode 51 and the respective surfaces 59 on both sides of the inner surface 56. In that case, it is preferable to chamfer at least the region (R2) from the position in the axis X direction corresponding to the tip 20 of the insulating member 21 to the tip 55 of the insulating member 21. Furthermore, it is preferable to chamfer the outer peripheral edge of the front end surface 55b of the ground electrode 51.
- a cylindrical noble metal tip is positioned concentrically on the front end surface of the center electrode base material, and at two positions (180 degrees) facing each other across the center C1 on the joint surface, A laser welding machine is arranged so that the outer peripheral edge of the joint surface can be laser welded. Then, a cylindrical noble metal tip is positioned concentrically on the tip surface of the center electrode base material, and then pulse laser welding is performed.
- FIG. 9 shows that after the positioning, the center electrode base material is rotated nearly 1/2 times (for example, 135 degrees) around its axis, and in each direction, the first (1st) position at the start of rotation (stop). From the pulse laser welding to the final 4th (4th) pulse laser welding, the weld beads 6 and 6e in a state where pulse laser welding is performed at four equiangular intervals are schematically shown.
- each of the first (1st) to third (3rd) shots The last 4th (4th) pulsed laser welding bead 6e is compared with the previous 6th laser beam welding bead 6e, and when viewed from the axial direction, the last 3rd bead 6 and the other laser welding machine
- the first bead 6 is formed on both sides so as to overlap each other.
- the final fourth bead (4th) bead 6e is present at two opposing positions (180 degrees) across the center C1 of the chip, which are slightly outward from the other bead 6 portions.
- a convex portion hatching portion in FIG.
- both the tops 8 of the two convex portions 7 are the bases of the center C1 of the noble metal tip and the ground electrode 51. What is necessary is just not to exist on the straight line S1 which connects the center C2 of the circumferential direction in the end 52, and to be in the position away from the straight line S1 in the circumferential direction.
- the two convex parts 7 are located at one opposing each other in the circumferential direction, a bead formed relatively low in the radial direction at an intermediate part or an intermediate part in the circumferential direction of the two convex parts 7
- the portion 6 exists on a straight line S1 connecting the center C1 of the noble metal tip and the center in the circumferential direction at the base end 52 of the ground electrode 51.
- the angle ⁇ formed by the straight line S1 and the straight line S2 connecting the top 8 of each convex portion 7 and the center C1 of the noble metal tip is 90 degrees (or about 90 degrees as shown in FIG. 9). ) Is preferred.
- the angular interval between the convex portions is 120 degrees, so the angle ⁇ is at most 60 degrees. It is preferable to assemble the spark plug by adjusting the position of the metal shell relative to the ground electrode 51 so as to be held at 45 degrees or more.
- FIG. 11B when the cylindrical noble metal tip 1 is positioned concentrically on the tip surface 13 of the center electrode base material 10, as shown in FIG. In the case where the noble metal tip 1 is positioned on the front end surface 13 of the center electrode base material 10 with a relatively large eccentric error D1 in the direction of arrow E and is welded as it is as shown in FIG. is there.
- the bead 6 even if it is not the bead 6e at the final end, the bead 6 also forms a convex portion 7b that is formed relatively high in the radial direction, as shown on the upper right in FIG. .
- the number of convex portions is three places including the convex portions 7 at the end of two beads.
- the distance between the two protrusions 7 having the maximum distance in the circumferential direction that is, the distance between the two protrusions 7 of the bead end 6e where the protrusion due to the eccentric error does not exist is the maximum.
- the circumferentially spaced portion formed by the two protrusions 7 of the bead end 6e faces the base end 52 side of the ground electrode 51, and each of the two protrusions 7
- the top 8 may be located at a position away from the straight line S1 connecting the center C1 of the noble metal tip and the center in the circumferential direction at the base end 52 of the ground electrode 51 in the circumferential direction. That is, in this example, the two convex portions 7 of the bead end 6e are held in the same positional relationship as the previous example as a result.
- the two convex portions 7 and 7b may be in close positions.
- the distance between the two convex portions 7 and 7b in the circumferential direction increases on the side where the two convex portions 7 and 7b are close to each other and on the opposite side across the center C1. . Therefore, in such a case, the circumferentially spaced portion (bead 6) formed by the two convex portions 7 and 7b having the largest circumferential spacing is located on the base end 52 side of the ground electrode 51.
- the top 8 of each of the two convex portions 7 and 7b may be positioned away from the straight line S1 connecting the center C1 of the noble metal tip and the circumferential center at the base end 52 of the ground electrode 51 in the circumferential direction.
- the angle ⁇ formed by the straight line S1 and the straight line S2 is about 90 degrees, but the base end 52 of the ground electrode 51 is shown by a one-dot chain line in FIG. You may move relatively to the position as indicated by. That is, the two convex portions 7 and 7b may not exist in the circumferential portion (half-circular portion) facing the base end 52 of the ground electrode 51.
- the convex portion formed relatively high in the radial direction does not exist on a straight line connecting the center of the noble metal tip and the center of the circumferential direction at the base end of the ground electrode. It is preferable to be in a remote location. Therefore, if the number of protrusions is one, the setting of the position is easy, but if there are a plurality of protrusions, the tops of all the protrusions are located away from the straight line in the circumferential direction.
- the part (bead) of the interval in the circumferential direction formed by the two projections having the largest interval in the circumferential direction faces the proximal end side of the ground electrode, and the tops of the two projections are It is preferable that the distance between the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode is the same or substantially the same distance or angular interval in the circumferential direction.
- it can be embodied as a plug of each form as described above, as in the case of one.
- spark plug manufacturing method assembly method embodying the present invention.
- This manufacturing method has been described above, but the important point is how to embody the main part of the present invention. That is, when the spark plug is viewed from the front end side of the noble metal tip along the axial direction, the top of the convex portion formed relatively high in the radial direction is the center of the noble metal tip out of the bead by laser welding that circulates. And the center of the ground electrode at the base end in the circumferential direction is not on a straight line, but is located away from the straight line in the circumferential direction. Except for this point, there is no difference from a conventionally known spark plug manufacturing method.
- a constituent member such as a center electrode with a noble metal tip welded to the tip is inserted into a hollow shaft-like insulating member, and a constituent member such as a terminal electrode is disposed behind the center electrode.
- fixing the structural member such as the center electrode in the insulating member to assemble the insulating member assembly, and the insulating member assembly in which the structural member such as the center electrode is inserted and fixed. Is inserted from the rear end side of the metal shell into the inside of the cylindrical metal shell provided at the tip of the metal shell, and the insulating member assembly inserted in the metal shell is provided with the metal shell. And a caulking step of fixing the insulating member assembly in the metal shell.
- the top of the projecting portion formed relatively high in the radial direction among the beads by circulating laser welding has a circumferential direction at the center of the noble metal tip and the base end of the ground electrode. What is necessary is just to assemble so that it may exist in the position away from the said straight line in the said circumferential direction, without existing on the straight line which connects a center.
- a positioning jig 301 for the metal shell 41 as shown in the left diagram of FIG. 13 is prepared.
- the positioning jig 301 has a hole 303 through which a portion of the mounting screw 46 on the front end side of the metal shell 41 can be pinched with almost no gap.
- the metal shell 41 is attached to the positioning jig 301 by a ring flange portion 48 for seating. It is formed so as to be supported on the upper surface (the peripheral edge of the opening of the hole). Further, at the back of the hole 303, when the metal shell 41 having the ground electrode 51 fixed to the tip by welding is inserted into the hole 303 of the positioning jig 301 with the tip facing down, a recess in which the ground electrode 51 is positioned.
- ground electrode 51 positioning portion around the axis of the metal shell 41 305 is provided. Accordingly, the metal shell 41 is inserted into the hole 303 from the tip side, and the ground electrode 51 is inserted into the recess 305. Thereby, the metal shell 41 holds the ground electrode 51 by the positioning jig 301 in a predetermined direction around the axis. In this manufacturing stage, the ground electrode 51 has a shape extending straight forward from the tip of the metal shell 41, which corresponds to the center electrode after fixing the next insulating member assembly. Bent.
- the insulating member assembly (work in process on the left in FIG. 13) 22 in which the constituent members such as the center electrode are fixed and assembled in the insulating member 21 is attached to the metal shell 41 on the rear end side. It is gripped by a chuck at the tip of an insulating member assembly supply arm for assembly (not shown) that can be inserted from the front.
- the chuck includes rotation adjusting means for adjusting the rotation of the insulating member assembly 22 around its axis.
- the radial direction of the bead welding the noble metal tip at the tip of the insulating member assembly 22 is determined before the insulating member assembly 22 is inserted into the metal shell 41, the radial direction of the bead welding the noble metal tip at the tip of the insulating member assembly 22 is determined. The height is detected by the detecting means along the circumferential direction of the noble metal tip.
- the position around the axis of the top of the convex portion of the bead with respect to a straight line connecting the center of the noble metal tip and the center in the circumferential direction at the base end of the ground electrode 51 is adjusted. That is, based on the detection data, the position (reference position) in the circumferential direction that should face the proximal end side of the ground electrode on the outer peripheral surface of the noble metal tip is determined, and the reference position of the ground electrode is determined by the rotation adjusting means.
- the rotation of the insulating member assembly 22 is controlled in the chuck so as to face the base end side.
- the supply arm is driven so that the insulating member assembly 22 is aligned with the axis of the metal shell 41 and is shown in the right diagram of FIG. As described above, this is inserted into the metal shell 41.
- the O-ring 37, the talc 38, and the O-ring 37 are interposed between the inside of the large-diameter cylindrical portion behind the metal shell 41 (see FIG. 1). Thereafter, the caulking cylindrical portion 45 at the rear end of the metal shell 41 is crimped inward, and compressed toward the front end side to be plastically deformed.
- the ground electrode 51 is bent into a predetermined shape, whereby the spark plug 101 having the structure shown in FIG. 1 is manufactured.
- the height detection in the radial direction of the weld bead of the noble metal tip in the insulating member assembly 22 may be originally performed before the caulking process. Therefore, the insulating member assembly 22 can be inserted into the metal shell 41 or after the insertion, but can be easily performed before the metal shell 41 is inserted as in this example. And therefore preferred.
- the height of the bead in the radial direction may be detected by an enlarged image processing by camera photography or by laser measurement, or any other known detection means or measurement means.
- the insulating member assembly 22 is rotated once around its axis, and the radial protrusion amount (outer peripheral surface contour) of the bead is photographed by the camera 401 in the circumferential direction from the side of the noble metal tip.
- laser measurement may be used instead of camera shooting.
- the height of the bead in the radial direction can also be detected by enlarging image processing by photographing the noble metal tip with the camera 401 from the tip side.
- the radial height of the bead is detected over the circumferential direction, and the surface (reference position) that should face the base end of the ground electrode is determined from the detected data, and the reference position is determined accordingly.
- the rotation adjusting means may be programmed so as to face the base end side of the ground electrode.
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Abstract
Description
前記中心電極が、中心電極母材の先端に貴金属チップを溶接してなるものであって、該中心電極母材と該貴金属チップとの接合面の周囲を周方向に沿って1周以上周回してレーザ溶接してなるスパークプラグにおいて、
前記中心電極と前記接地電極との間の火花ギャップをGとし、
前記接地電極の基端において、前記中心電極を向く内面に沿って前記主体金具の軸Xに平行に引いた線と、レーザ溶接によるビードとの最短間隔をAとしたとき、
GとAとが、A≦3Gの寸法関係にあるようにし、
該スパークプラグを、前記貴金属チップの先端側から軸方向に沿って見たとき、
周回するレーザ溶接によるビードのうち、径方向に相対的に高く形成された凸部における頂部が、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線上に存在せず、該直線から前記周方向に離れた位置にあることを特徴とする。
前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線と、周回するレーザ溶接によるビードのうち、径方向に相対的に高く形成された凸部における頂部と前記貴金属チップの中心とを結ぶ直線とのなす角度θが45度以上保持されていることを特徴とする請求項1~3のいずれか1項に記載のスパークプラグである。
また、請求項5に記載の発明は、請求項4において、前記角度θが90度以上保持されていることを特徴とするスパークプラグである。
中心電極等の構成部材を内挿して固定した前記絶縁部材組付け体を、接地電極が自身の先端に設けられた筒状の主体金具の内側に、該主体金具の後端側から内挿する工程と、
該主体金具内に内挿した該絶縁部材組付け体を、該主体金具を加締めて、該絶縁部材組付け体を該主体金具内に固定する加締め工程を含むスパークプラグの製造方法において、
請求項1~11のいずれか1項に記載のスパークプラグを製造するにあたり、
前記主体金具の軸線回りにおける前記接地電極の位置を所定の位置として、該主体金具を位置決めしておく一方、
前記絶縁部材組付け体を前記主体金具に内挿する前から、前記加締工程において該主体金具を加締めるまでの間に、
前記ビードの径方向の高さを前記貴金属チップの周方向に沿って検出手段により検出し、かつその検出データに基づいて、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線に対する前記凸部における前記頂部の軸線回りの位置を調節しておくことを特徴とする。
中心電極等の構成部材を内挿して固定した前記絶縁部材組付け体を、接地電極が自身の先端に設けられた筒状の主体金具の内側に、該主体金具の後端側から内挿する工程と、
該主体金具内に内挿した該絶縁部材組付け体を、該主体金具を加締めて、該絶縁部材組付け体を該主体金具内に固定する加締め工程を含むスパークプラグの製造方法において、
請求項1~11のいずれか1項に記載のスパークプラグを製造するにあたり、
前記主体金具の軸線回りにおける前記接地電極の位置を所定の位置として、該主体金具を位置決めしておく一方、
前記絶縁部材組付け体を前記主体金具に内挿する前に、
前記ビードの径方向の高さを前記貴金属チップの周方向に沿って検出手段により検出し、かつその検出データに基づいて、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線に対する前記凸部における前記頂部の軸線回りの位置を調節しておくことを特徴とする。
3 貴金属チップの先端
6、6e レーザ溶接のビード
7 ビードの最終端部で、径方向に相対的に高く形成された凸部
7b 偏心誤差によるビードにおける凸部
8 凸部における頂部
10 中心電極母材
11 中心電極
13 中心電極母材の先端
21 絶縁部材
40 主体金具の先端
41 主体金具
51 接地電極
52 接地電極の基端
52b 接地電極の基端における周方向の中心
55 接地電極の先端
56 接地電極の中心電極側を向く内面
59 内面の両側の各面
60 面取り
101、201 スパークプラグ
G 火花ギャップ(正規ギャップ)
A 横ギャップ
C1 貴金属チップの先端の中心
C2 接地電極の基端における周方向の中心
S1 貴金属チップの先端の中心と接地電極の基端における周方向の中心を結ぶ直線
S2 ビードの凸部における頂部と貴金属チップの中心とを結ぶ直線
θ 直線S1とS2とのなす角度
X 軸
Claims (15)
- 先端に中心電極を配置した中空軸状の絶縁部材と、この絶縁部材を包囲し、前記中心電極とで火花ギャップを形成する接地電極を先端に備えた主体金具とを有し、
前記中心電極が、中心電極母材の先端に貴金属チップを溶接してなるものであって、該中心電極母材と該貴金属チップとの接合面の周囲を周方向に沿って1周以上周回してレーザ溶接してなるスパークプラグにおいて、
前記中心電極と前記接地電極との間の火花ギャップをGとし、
前記接地電極の基端において、前記中心電極を向く内面に沿って前記主体金具の軸Xに平行に引いた線と、レーザ溶接によるビードとの最短間隔をAとしたとき、
GとAとが、A≦3Gの寸法関係にあるようにし、
該スパークプラグを、前記貴金属チップの先端側から軸方向に沿って見たとき、
周回するレーザ溶接によるビードのうち、径方向に相対的に高く形成された凸部における頂部が、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線上に存在せず、該直線から前記周方向に離れた位置にあることを特徴とするスパークプラグ。 - 前記凸部が周方向において複数存在し、そのいずれの頂部も、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線上に存在せず、しかも、該直線から前記周方向に離れた位置にあることを特徴とする請求項1に記載のスパークプラグ。
- 前記凸部が周方向において複数存在し、その周方向における間隔が最大となる2つの凸部のなす該周方向における間隔の部位が、前記接地電極の基端側を向き、その2つの凸部の各頂部が、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線から前記周方向に離れた位置にあることを特徴とする請求項1に記載のスパークプラグ。
- 前記スパークプラグを、前記貴金属チップの先端側から軸方向に沿って見たとき、
前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線と、周回するレーザ溶接によるビードのうち、径方向に相対的に高く形成された凸部における頂部と前記貴金属チップの中心とを結ぶ直線とのなす角度θが45度以上保持されていることを特徴とする請求項1~3のいずれか1項に記載のスパークプラグ。 - 請求項4において、前記角度θが90度以上保持されていることを特徴とするスパークプラグ。
- 前記接地電極は、前記主体金具の先端から先方に延び、前記中心電極をなす貴金属チップの先端面との間で火花ギャップが形成されるように、自身の先端が該貴金属チップ側に曲げられてなることを特徴とする請求項1~5のいずれか1項に記載のスパークプラグ。
- 請求項6において、前記接地電極には、前記中心電極側を向く内面と、該内面の両側の各面とのなす各コーナーのうち、少なくとも、前記絶縁部材の先端から軸方向に突出している前記中心電極の突出長に対応する部分に対し、面取りが付与されていることを特徴とするスパークプラグ。
- 前記接地電極は、前記主体金具の先端から先方に延び、前記中心電極をなす貴金属チップの外周面との間で火花ギャップが形成されるように、自身の先端が該貴金属チップ側に曲げられてなることを特徴とする請求項1~5のいずれか1項に記載のスパークプラグ。
- 請求項8において、前記接地電極には、前記中心電極側を向く内面と、該内面の両側の各面とのなす各コーナーのうち、少なくとも、前記絶縁部材の先端に対応する軸方向における位置から、接地電極自身の先端まで、面取りが付与されていることを特徴とするスパークプラグ。
- 前記接地電極に貴金属チップがレーザ溶接されていることを特徴とする請求項1~9のいずれか1項に記載のスパークプラグ。
- 前記レーザ溶接はパルスレーザ溶接であることを特徴とする請求項1~10のいずれか1項に記載のスパークプラグ。
- 先端に貴金属チップが溶接された中心電極等の構成部材を中空軸状の絶縁部材内に内挿し、この中心電極の後方に端子電極等の構成部材を配置して該絶縁部材内に中心電極等の構成部材を固定して絶縁部材組付け体を組付ける工程と、
中心電極等の構成部材を内挿して固定した前記絶縁部材組付け体を、接地電極が自身の先端に設けられた筒状の主体金具の内側に、該主体金具の後端側から内挿する工程と、
該主体金具内に内挿した該絶縁部材組付け体を、該主体金具を加締めて、該絶縁部材組付け体を該主体金具内に固定する加締め工程を含むスパークプラグの製造方法において、
請求項1~11のいずれか1項に記載のスパークプラグを製造するにあたり、
前記主体金具の軸線回りにおける前記接地電極の位置を所定の位置として、該主体金具を位置決めしておく一方、
前記絶縁部材組付け体を前記主体金具に内挿する前から、前記加締工程において該主体金具を加締めるまでの間に、
前記ビードの径方向の高さを前記貴金属チップの周方向に沿って検出手段により検出し、かつその検出データに基づいて、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線に対する前記凸部における前記頂部の軸線回りの位置を調節しておくことを特徴とするスパークプラグの製造方法。 - 先端に貴金属チップが溶接された中心電極等の構成部材を中空軸状の絶縁部材内に内挿し、この中心電極の後方に端子電極等の構成部材を配置して該絶縁部材内に中心電極等の構成部材を固定して絶縁部材組付け体を組付ける工程と、
中心電極等の構成部材を内挿して固定した前記絶縁部材組付け体を、接地電極が自身の先端に設けられた筒状の主体金具の内側に、該主体金具の後端側から内挿する工程と、
該主体金具内に内挿した該絶縁部材組付け体を、該主体金具を加締めて、該絶縁部材組付け体を該主体金具内に固定する加締め工程を含むスパークプラグの製造方法において、
請求項1~11のいずれか1項に記載のスパークプラグを製造するにあたり、
前記主体金具の軸線回りにおける前記接地電極の位置を所定の位置として、該主体金具を位置決めしておく一方、
前記絶縁部材組付け体を前記主体金具に内挿する前に、
前記ビードの径方向の高さを前記貴金属チップの周方向に沿って検出手段により検出し、かつその検出データに基づいて、前記貴金属チップの中心と前記接地電極の基端における周方向の中心とを結ぶ直線に対する前記凸部における前記頂部の軸線回りの位置を調節しておくことを特徴とするスパークプラグの製造方法。 - 請求項12又は13において、前記検出手段を、カメラ撮影による画像処理によることとしたスパークプラグの製造方法。
- 請求項12又は13において、前記検出手段を、レーザ計測によることとしたスパークプラグの製造方法。
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US13/123,467 US8212462B2 (en) | 2008-10-10 | 2009-10-09 | Spark plug and manufacturing method therefor |
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KR101550089B1 (ko) * | 2009-03-31 | 2015-09-03 | 니혼도꾸슈도교 가부시키가이샤 | 스파크 플러그의 제조방법 |
DE102013105698B4 (de) | 2012-06-01 | 2019-05-02 | Federal-Mogul Ignition Company | Zündkerze |
US9673593B2 (en) | 2012-08-09 | 2017-06-06 | Federal-Mogul Ignition Company | Spark plug having firing pad |
US9318879B2 (en) | 2012-10-19 | 2016-04-19 | Federal-Mogul Ignition Company | Spark plug having firing pad |
US9231379B2 (en) | 2013-01-31 | 2016-01-05 | Federal-Mogul Ignition Company | Spark plug having firing pad |
US9041274B2 (en) | 2013-01-31 | 2015-05-26 | Federal-Mogul Ignition Company | Spark plug having firing pad |
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JP5755708B2 (ja) * | 2013-11-15 | 2015-07-29 | 日本特殊陶業株式会社 | スパークプラグの製造方法 |
JP2015133243A (ja) * | 2014-01-14 | 2015-07-23 | 日本特殊陶業株式会社 | スパークプラグ |
CN105684245B (zh) * | 2014-05-15 | 2017-07-18 | 日本特殊陶业株式会社 | 火花塞 |
JP6427133B2 (ja) * | 2016-03-29 | 2018-11-21 | 日本特殊陶業株式会社 | スパークプラグ |
JP2018029005A (ja) * | 2016-08-17 | 2018-02-22 | 日本特殊陶業株式会社 | スパークプラグ |
JP6425698B2 (ja) * | 2016-09-22 | 2018-11-21 | 日本特殊陶業株式会社 | スパークプラグ |
DE102017107728A1 (de) | 2017-04-10 | 2018-10-11 | Federal-Mogul Ignition Gmbh | Vorkammerzündkerze und Verfahren zu deren Herstellung |
JP6566988B2 (ja) * | 2017-05-11 | 2019-08-28 | 日本特殊陶業株式会社 | 点火プラグ |
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