WO2009130909A1 - スパークプラグ - Google Patents
スパークプラグ Download PDFInfo
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- WO2009130909A1 WO2009130909A1 PCT/JP2009/001867 JP2009001867W WO2009130909A1 WO 2009130909 A1 WO2009130909 A1 WO 2009130909A1 JP 2009001867 W JP2009001867 W JP 2009001867W WO 2009130909 A1 WO2009130909 A1 WO 2009130909A1
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- WIPO (PCT)
- Prior art keywords
- tip
- spark plug
- electrode
- noble metal
- intermediate member
- 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
- 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 that forms a spark gap between a tip portion of a center electrode and a noble metal tip disposed on a ground electrode.
- Spark plugs are required not only to have a long service life to achieve maintenance-free, but also to improve ignitability and combustion efficiency by miniaturizing the electrodes.
- platinum is added to the spark discharge part of the center electrode. Spark plugs joined with precious metal chips such as iridium are widely used.
- the noble metal tip it has been proposed to arrange the noble metal tip not only on the center electrode but also on the ground electrode (outer electrode) (see, for example, JP-A-2004-134209).
- the noble metal tip when the noble metal tip is fixed to the ground electrode, the noble metal tip is fixed to a member (intermediate member) different from the ground electrode by laser welding, and then the noble metal tip is fixed.
- the intermediate member to which is bonded is joined to the ground electrode by resistance welding.
- the present invention is based on the viewpoint of focusing on the mechanical characteristics of the intermediate member and the ground electrode, which has not been attempted in the past, and the center of the noble metal tip disposed on the ground electrode after the bending process of the ground electrode.
- the spark plug according to one aspect of the present invention is configured as follows. That is, a center electrode, an axial hole extending along the axial direction, an insulator that holds the center electrode in the axial hole, a metal shell that surrounds and holds the insulator in the circumferential direction, and a base end
- a ground electrode having a middle portion between the base end portion and the front end portion bent so that a portion is joined to the metal shell and a front end portion faces the front end portion of the center electrode
- the noble metal tip is joined to the top surface of an intermediate member separate from the ground electrode and integrated with the intermediate member, and the bottom surface of the intermediate member is joined to the ground electrode.
- the tip is Are arranged with respect to the electrodes, the average hardness of the intermediate member is summarized in that higher than the average hard
- the average hardness of the intermediate member is higher than the average hardness of the portion excluding the intermediate portion of the ground electrode.
- the spark plug described above can be configured as follows. For example, if the average hardness of the ground electrode is less than 180 Hv in terms of Vickers hardness, the bending process of the ground electrode can be performed without any particular trouble, and further correction of the misalignment between the center axis of the noble metal tip and the center axis of the center electrode can be further performed. Can be done appropriately. If the average hardness of the intermediate member is set to 180 Vv or more in terms of Vickers hardness, it is possible to more appropriately correct the misalignment between the center axis of the noble metal tip and the center axis of the center electrode.
- the intermediate member has a large-diameter portion formed on the ground electrode side and a small-diameter portion formed on the noble metal tip side, and at least of the large-diameter portion and the small-diameter portion.
- the small diameter portion may be constituted by a fibrous metal structure along a direction substantially parallel to the central axis of the noble metal tip.
- the intermediate member is configured such that at least half of the intermediate member on the noble metal tip side has a fibrous metal structure along a direction substantially parallel to the central axis of the noble metal tip. May be. Even with such a configuration, it is possible to increase the resistance to the force applied to the intermediate member when correcting the misalignment of the noble metal tip. Therefore, the axial deviation of the noble metal tip can be corrected more appropriately.
- a melted portion in which the intermediate member and the noble metal tip are melted may be formed between the intermediate member and the noble metal tip.
- the distance from the surface of the ground electrode to which the intermediate member is joined to the end portion on the noble metal tip side on the surface of the molten portion may be 0.3 mm or more.
- the distance from the tip surface of the noble metal tip to the end portion on the noble metal tip side on the surface of the melted portion may be 0.1 mm or more. With such a configuration, it is possible to suppress consumption of the tip of the noble metal tip.
- the average hardness of the melted portion may be 180 Hv or more in terms of Vickers hardness.
- the intermediate member and the ground electrode may be formed of an alloy material having the same composition ratio. In this way, it is possible to increase the bonding strength between the intermediate member and the ground electrode.
- the noble metal tip is mainly composed of platinum (Pt), iridium (Ir), rhodium (Rh), nickel (Ni), tungsten (W), palladium (Pd), ruthenium (Ru). , And may contain at least one kind of rhenium (Re) metal.
- Pt platinum
- Ir iridium
- Rhodium Rh
- Ni nickel
- tungsten W
- Pd palladium
- Ru ruthenium
- Re rhenium
- a center electrode-side noble metal tip may be bonded to the tip of the center electrode, and the center electrode-side noble metal tip may face the noble metal tip. In this way, since the spark gap is formed between the noble metal tips arranged to face each other, the ignitability and durability are improved.
- the noble metal tip on the center electrode side is mainly composed of iridium (Ir), platinum (Pt), rhodium (Rh), nickel (Ni), tungsten (W), palladium (Pd), ruthenium. (Ru), rhenium (Re), aluminum (Al), aluminum oxide (Al 2 O 3 ), yttrium (Y), and yttrium oxide (Y 2 O 3 ). Also good. If such a center electrode side noble metal tip is employed, the consumption of the center electrode side noble metal tip itself can be suppressed due to its compositional properties.
- FIG. 2 is an enlarged view showing the vicinity of the tip of a center electrode 20 in the spark plug 100.
- FIG. It is process drawing which shows a plug manufacture procedure. It is explanatory drawing which shows typically the mode of the operation
- count of outer side bending which is an evaluation item in FIG. 3 is an enlarged cross-sectional view of the periphery of a tip portion 31 of a ground electrode 30.
- FIG. 1 is a partial cross-sectional view of a spark plug 100 as an embodiment of the present invention
- FIG. 2 is an enlarged view showing the vicinity of the tip of a center electrode 20 in the spark plug 100.
- the axis O direction of the spark plug 100 shown in FIG. 1 is the vertical direction
- the lower side is the front end side of the spark plug 100
- the upper side is the rear end side.
- the spark plug 100 includes an insulator 10 as an insulator, a metal shell 50 that holds the insulator 10, a center electrode 20 that is held in the insulator 10 in the direction of the axis O, and a ground.
- the electrode 30 and the terminal metal fitting 40 provided in the rear-end part of the insulator 10 are provided.
- the insulator 10 is formed by firing alumina or the like, and has a cylindrical shape in which an axial hole 12 extending in the direction of the axis O is formed at the axial center.
- a flange portion 19 having the largest outer diameter is formed substantially at the center in the direction of the axis O, and a rear end body portion 18 is formed on the rear end side (upper side in FIG. 1).
- a front end side body portion 17 having a smaller outer diameter than the rear end side body portion 18 is formed on the front end side from the flange portion 19 (lower side in FIG. 1), and further, on the front end side from the front end side body portion 17,
- a leg length portion 13 having an outer diameter smaller than that of the distal end side body portion 17 is formed.
- the long leg portion 13 is reduced in diameter toward the tip side, and is exposed to the combustion chamber when the spark plug 100 is attached to the engine head 200 of the internal combustion engine.
- a step portion 15 is formed between the long leg portion 13 and the front end side body portion 17.
- the center electrode 20 is heated more than the electrode base material 21 inside the electrode base material 21 formed of nickel or an alloy containing nickel as a main component, such as Inconel (trade name) 600 or 601.
- This is a rod-shaped electrode having a structure in which a core material 25 made of copper having excellent conductivity or an alloy containing copper as a main component is embedded.
- the center electrode 20 is produced by filling a core material 25 inside an electrode base material 21 formed in a bottomed cylindrical shape, and performing extrusion molding from the bottom side and stretching it.
- the core member 25 has a substantially constant outer diameter at the body portion, but is formed in a tapered shape at the distal end side.
- the center electrode 20, specifically, the electrode base material 21, includes a tapered electrode base material base 22, a melting portion 23, and an electrode tip 70, which have a small diameter toward the tip, and includes the electrode tip 70.
- the electrode tip 70 is formed with a high melting point noble metal as a main component in order to improve spark wear resistance.
- this electrode chip 70 for example, iridium (Ir), Ir as a main component, platinum (Pt), rhodium (Rh), Ni (nickel), tungsten (W), palladium (Pd), ruthenium (Ru) , Rhenium (Re), aluminum (Al), aluminum oxide (Al 2 O 3 ), yttrium (Y), yttrium oxide (Y 2 O 3 ), and an Ir alloy to which at least one kind is added.
- -5Pt alloy iridium alloy containing 5% by mass of platinum
- Ir-11Ru-8Rh-1Ni alloy iridium alloy containing 11% by mass of ruthenium, 8% by mass of rhodium and 1% by mass of nickel
- the shortest distance (tip length) in the axial direction from the boundary between the electrode tip 70 and the melting portion 23 to the tip of the electrode tip 70 is set to 0.5 to 1.2 mm.
- the melting part 23 is formed through welding of the electrode tip 70 to the electrode base pedestal 22, for example, laser welding that irradiates a laser and melts the electrode base pedestal 22 and the electrode tip 70 by the heat. That is, in a state where the electrode tip 70 is disposed on the tip surface of the electrode base material pedestal 22, while irradiating a laser aiming at the boundary surface between the electrode base material base 22 and the electrode tip 70, the irradiated portion is arranged around the entire boundary surface. Make one round. In this laser welding, since both materials (the constituent material of the electrode base material base 22 and the noble metal of the electrode tip 70) are melted and mixed by laser irradiation, the electrode tip 70 and the electrode base material base 22 are firmly joined. At the same time, the melting portion 23 that connects the electrode base material base 22 and the electrode tip 70 is formed. The melting portion 23 is formed as an alloy of both materials by melting the both materials.
- the center electrode 20 extends in the shaft hole 12 toward the rear end side, and is electrically connected to the terminal fitting 40 on the rear side (upper side in FIG. 1) via the seal body 4 and the ceramic resistor 3 (see FIG. 1). Connected.
- a high voltage cable (not shown) is connected to the terminal fitting 40 via a plug cap (not shown), and a high voltage is applied.
- the ground electrode 30 is made of a metal having high corrosion resistance. As an example, a nickel alloy such as Inconel (trade name) 600 or 601 is used.
- the ground electrode 30 has a substantially rectangular cross section in a direction orthogonal to the longitudinal direction of the ground electrode 30.
- the ground electrode 30 is joined to the distal end surface 57 of the metal shell 50 by welding at the base end portion 32, and the distal end portion 31.
- the intermediate portion 33 between the distal end portion 31 and the proximal end portion 32 is bent so that one side surface thereof faces the electrode tip 70 of the center electrode 20 on the axis O.
- An electrode tip 80 is disposed at the tip 31 of the ground electrode 30 at a position facing the electrode tip 70 joined to the center electrode 20.
- the electrode tip 80 is a noble metal tip formed with a noble metal as a main component in the same manner as the electrode tip 70 on the center electrode 20 side.
- platinum (Pt) is the main component and iridium (Ir), rhodium ( Rt), nickel (Ni), tungsten (W), palladium (Pd), ruthenium (Ru), rhenium (Re), and a Pt-20Rh alloy (20% by mass).
- a platinum alloy containing rhodium) and a Pt-20Ir-5Rh alloy (a platinum alloy containing 20% by mass of iridium and 5% by mass of rhodium) are frequently used.
- the electrode tip 80 is previously joined to the top surface of the intermediate member 81 separate from the ground electrode 30 by laser welding or the like. That is, the electrode tip 80 and the intermediate member 81 are integrated with each other through the melting portion 82 generated by welding.
- the intermediate member 81 is formed of the same Inconel 600 or Inconel 601 nickel alloy as the ground electrode 30.
- the intermediate member 81 has a columnar shape, and the ground electrode 30 side is formed with a large diameter, and the electrode chip 80 side is formed with a small diameter via a stepped portion.
- the thick diameter portion of the intermediate member 81 is referred to as a lower end flange portion 83, and the thin diameter portion is referred to as a small diameter portion 84.
- the intermediate member 81 for example, a rod-shaped metal material having a thickness corresponding to the lower end flange portion 83 is prepared, and the thin-diameter portion 84 is formed by subjecting this metal material to header processing which is one of plastic processing. It can be manufactured by forming. It is also possible to prepare a rod-like metal material thicker than the lower end flange portion 83 and form both the lower end flange portion 83 and the small diameter portion 84 by header processing.
- the electrode tip 80 is disposed on the ground electrode 30 (specifically, the tip 31).
- the bottom surface of the lower end flange portion 83 of the intermediate member 81 to which the electrode tip 80 is bonded is the one side of the tip 31 of the ground electrode 30. This is performed by pressing against the chip mounting surface 31S and joining the lower end flange portion 83 to the distal end portion 31 of the ground electrode 30 by resistance welding or the like.
- the ground electrode 30 is bent at the intermediate portion 33 so that the tip surface of the electrode tip 80 faces the tip surface and the end surface of the electrode tip 70 in the center electrode 20. As a result, a spark gap GA is formed between the electrode tip 70 and the electrode tip 80.
- the spark gap GA is set to 0.3 to 1.5 mm, and as described later, the deviation of the axis O ′ of the electrode chip 80 from the axis O of the electrode chip 70, that is, The parallelism between the distal end surface of the electrode tip 70 and the distal end surface of the electrode tip 80, or the distal end surface of the electrode tip 80 and the tip mounting surface 31S to which the intermediate member 81 in the distal end portion 31 of the ground electrode 30 is joined.
- the deviation in parallelism is set to be less than 4 °.
- the tip length from the side surface of the tip 31 of the ground electrode 30 of the electrode tip 80 that forms the spark gap GA as described above is set to 0.5 to 1.2 mm, which is the same as that of the electrode tip 70.
- the main metal fitting 50 is a cylindrical metal fitting for fixing the spark plug 100 to the engine head 200 of the internal combustion engine.
- the metal shell 50 holds the insulator 10 inside so as to surround a portion from a part of the rear end side body part 18 to the leg long part 13.
- the metal shell 50 is formed of a low carbon steel material, and has a thread engaging with a tool engaging portion 51 into which a spark plug wrench (not shown) is fitted and a mounting screw hole 201 of the engine head 200 provided at the upper part of the internal combustion engine. And a formed mounting screw portion 52.
- the outer diameter M (nominal diameter) of the mounting screw 52 is M10 to M12.
- a bowl-shaped seal portion 54 is formed between the tool engaging portion 51 and the mounting screw portion 52 of the metal shell 50.
- An annular gasket 5 formed by bending a plate is fitted into a screw neck 59 between the mounting screw portion 52 and the seal portion 54.
- the gasket 5 is crushed and deformed between the seat surface 55 of the seal portion 54 and the opening peripheral edge portion 205 of the attachment screw hole 201. Due to the deformation of the gasket 5, the gap between the spark plug 100 and the engine head 200 is sealed, and airtight leakage in the engine through the mounting screw hole 201 is prevented.
- a thin caulking portion 53 is provided on the rear end side from the tool engaging portion 51 of the metal shell 50. Further, a thin buckled portion 58 is provided between the seal portion 54 and the tool engaging portion 51, similarly to the caulking portion 53. Between the inner peripheral surface of the metal shell 50 from the tool engagement portion 51 to the crimping portion 53 and the outer peripheral surface of the rear end side body portion 18 of the insulator 10, annular ring members 6 and 7 are interposed. Further, talc (talc) 9 powder is filled between the ring members 6 and 7. By crimping the crimping portion 53 so as to be bent inward, the insulator 10 is pressed toward the front end side in the metal shell 50 via the ring members 6, 7 and the talc 9.
- the step portion 15 of the insulator 10 is supported by the step portion 56 formed at the position of the mounting screw portion 52 on the inner periphery of the metal shell 50 via the annular plate packing 8 so as to be insulated from the metal shell 50.
- the insulator 10 is integrated.
- the buckling portion 58 is configured to buckle and deform outwardly when a compression force is applied during caulking, and the compression length in the direction of the axis O of the talc 9 is increased so that the inside of the metal shell 50 is increased. Increases airtightness.
- a clearance C having a predetermined dimension is provided between the metal shell 50 and the insulator 10 on the tip side of the step portion 56.
- FIG. 3 is a process diagram showing the plug manufacturing procedure
- FIG. 4 is an explanatory diagram schematically showing the state of work in this manufacturing process
- FIG. 5 is an explanatory diagram showing the state after adjusting the chip axis deviation in the manufacturing process.
- the center electrode 20, the insulator 10, and the metal shell 50 are prepared (step S100).
- the electrode tip 70 is already joined to the electrode base material base 22 with the melting portion 23 interposed in the center electrode 20.
- the proximal end portion 32 of the ground electrode 30 is fixed to the distal end surface of the metal shell 50 by welding.
- the insulator 10 is assembled so as to cover the outer periphery of the center electrode 20 while exposing the tip of the center electrode 20 (specifically, the electrode tip 70, the melting part 23, and the electrode base plate 22) (step S110).
- the metal shell 50 is assembled on the outer periphery of the insulator 10 so that the tip of the insulator 10 protrudes from the tip surface of the metal shell 50 by, for example, about 2 mm or more (step S120).
- the electrode tip 80 integrated with the intermediate member 81 via 82 is fixed to the ground electrode 30 by joining the lower end flange portion 83 of the intermediate member 81 to the tip mounting surface 31S of the ground electrode 30 (step S130).
- the ground electrode 30 is bent toward the center electrode 20 (step S140).
- a bender for causing an intermediate portion 33 having a predetermined radius of curvature to be formed at the bent portion of the ground electrode 30.
- the jig JB is pressed and bent so that the tip 31 of the ground electrode 30 faces the electrode tip 70.
- the ground electrode 30 is bent with a predetermined radius of curvature so that the electrode tip 70 and the electrode tip 80 are substantially opposed to each other.
- interval of the electrode tip 70 and the electrode tip 80, ie, the spark gap GA is formed with the above-mentioned predetermined dimension.
- the axis deviation of the electrode tip 80 is adjusted (step S150).
- the intermediate member 81 is gripped by the lower end flange portion 83 side with the tip gripping jig JG, and the tip surface of the electrode tip 80 and the electrode
- the deviation in parallelism with the tip surface of the tip 70 or the deviation in parallelism between the tip surface of the electrode tip 80 and the tip mounting surface 31S of the electrode tip 80 at the tip 31 of the ground electrode 30 is less than 4 °.
- the axis deviation of the electrode tip 80 is adjusted by the tip gripping jig JG.
- the crossing angle ⁇ of the axis O ′ of the electrode tip 80 with respect to the axis O of the electrode tip 70 becomes less than 4 °, and the tip surface of the electrode tip 80 and the tip of the electrode tip 70 The plane faces the plane almost in parallel within this angular range.
- FIG. 6 is an explanatory view showing the relationship between the average hardness and the evaluation result while changing the material of the intermediate member 81 and the ground electrode 30, and
- FIG. 7 is an explanatory view showing the calculation of the number of times of outer bending, which is the evaluation item in FIG. 6. It is.
- both the intermediate member 81 and the ground electrode 30 are formed of Inconel 600 represented by the material A in the figure, and the average hardness of the ground electrode 30 is 161 Hv in terms of Vickers hardness.
- the average hardness of the intermediate member 81 excluding the portion 82 and the lower end flange portion 83) is 164Hv.
- melting part 82 is 210Hv.
- this average hardness is performed in accordance with Japanese Industrial Standard (JIS Z 2224 / test force 4.903N), and the average hardness of the ground electrode 30 is, for example, the joining portion of the intermediate member 81 shown in FIG.
- the average hardness of the ground electrode 30 may be a portion excluding the bent intermediate portion 33, or may be a portion near the base end portion 32 of the ground electrode 30.
- the average hardness of the intermediate member 81 is an average value of measured hardness at three points on the surface of the intermediate member 81 and the lower end flange portion 83 on the side of the lower end flange portion 83 from the melt portion 82, that is, the range excluding the melt portion 82. In this case, the average hardness of the intermediate member 81 may be an average value of the measured hardness at 10 points.
- a plurality of spark plugs manufactured under the same conditions may be used to average the measured hardness at 10 points. In that case, an average value obtained by a plurality of spark plugs is also used for the bending test.
- the spark plug 1 of FIG. 7 has a base end portion 32 mainly formed by seven bendings when a bending test in which the ground electrode 30 is repeatedly bent outward at the base end portion 32 away from the center electrode 20 is performed.
- the measurement result of the intersecting angle ⁇ (see FIG. 5) of the axis O ′ of the electrode tip 80 with respect to the axis O of the electrode tip 70 after breaking from the metal fitting 50 and adjusting the axis deviation in step S150 of FIG. 3 is 5 °. It is shown that.
- the ground electrode 30 is broken from the base end portion 32 when the ground electrode 30 shown in FIG. It was judged as bad (NG).
- the crossing angle ⁇ of the axis is 4 ° or more, it was judged as defective (NG) for the following reason.
- the tip surface of the electrode tip 80 is inclined with respect to the tip surface of the electrode tip 70 on the center electrode 20 side as the crossing angle ⁇ is larger.
- the discharge at the spark gap GA is concentrated on the portion of the tip surface of the tilted electrode tip 80 that is closest to the electrode tip 70 on the center electrode 20 side. Therefore, the portion of the tip surface of the electrode tip 80 that is closest to the electrode tip 70 on the center electrode 20 side is likely to be consumed.
- the spark gap GA becomes larger as the tip end surface is consumed, so there is a concern that the stability of discharge, and hence the ignitability, may decrease. For this reason, the crossing angle ⁇ of the axis of 4 ° or more is regarded as defective (NG).
- No. shown in FIG. Of Nos. 1 to 16 No. (No.) is a non-defective product (OK) in both the above-mentioned outer bending times and crossing angle ⁇ evaluation items.
- No. 2 to 3, 5, 8, 10 and 13 to 15 spark plugs 100.
- Nos. 2 to 3 and 5 are formed such that both the intermediate member 81 and the ground electrode 30 are made of the material A (Inconel 600).
- Nos. 8, 10 and 13 are formed such that both the intermediate member 81 and the ground electrode 30 are made of the material B (Inconel 601). 14 to 15, the intermediate member 81 is formed from the material A (Inconel 600), and the ground electrode 30 is formed from the material B (Inconel 601).
- the average hardness of the intermediate member 81 was higher than the average hardness of the ground electrode 30 in the measurement area HR around the joint portion shown in FIG. Moreover, it was confirmed that the average hardness of the ground electrode 30 was less than 180 Hv in terms of Vickers hardness, and the average hardness of the intermediate member 81 was 180 Hv or more, preferably 200 Hv or more in terms of Vickers hardness. Further, the average hardness of the melted portion 82 was 180 Hv or more, and it was confirmed that the average hardness was approximately 200 to 300 Hv.
- the material of these members is made of the material A (Inconel 600) or the material B (Inconel 601).
- the joining conditions of the intermediate member 81 and the conditions for welding the ground electrode 30 to the metal shell 50 at the base end portion 32 are averaged. If the relationship between the hardness and the average hardness of the intermediate member 81 is defined so as to satisfy the above relationship, the evaluation items (the number of outer bendings and the crossing angle ⁇ ) are satisfied. Therefore, if the joining of the intermediate member 81 and the welding of the ground electrode 30 are performed under the above defined conditions, the ground electrode 30 can be prevented from being damaged, and the adjustment of the axial deviation of the electrode tip 80 can be simplified. preferable.
- the following can also be performed.
- the joining of the intermediate member 81 and the welding of the ground electrode 30 cause a decrease in hardness due to annealing. Therefore, in anticipation of this hardness reduction, when the intermediate member 81 and the ground electrode 30 are formed from either the material A (Inconel 600) or the material B (Inconel 601), the hardness is increased in advance. It is also effective.
- the average hardness of the ground electrode 30 is 180 Hv or more, the ground electrode 30 is too hard, and thus a large force is required when the ground electrode 30 is bent. Therefore, the stress applied to the welded portion of the base end portion 32 is also increased, and the stress exceeding the welding strength is applied. That is, it has been confirmed that the average hardness of the ground electrode 30 needs to be less than 180 Hv in order to satisfy the number of times of outer bending for evaluating avoidance of welding fracture of the ground electrode 30.
- the average hardness of the ground electrode 30 is less than 180 Hv, but the average hardness of the intermediate member 81 is less than 180 Hv. This is expected to cause an axial deviation of the electrode tip 80 when adjusting the axial deviation because the average hardness of the intermediate member 81 is low. That is, it has been confirmed that the average hardness of the intermediate member 81 needs to be 180 Hv or more in order to suppress the axial deviation of the electrode tip 80 and satisfy the predetermined crossing angle ⁇ .
- the distance L1 from the chip mounting surface 31S of the ground electrode 30 to the upper end of the surface of the melting part 82 may be 0.3 mm or more.
- FIG. 8 is an enlarged cross-sectional view around the tip 31 of the ground electrode 30.
- the electrode tip 80 is formed of a noble metal such as platinum, the electrode tip 80 has a high hardness (approximately 300 Hv), but has a property of being easily chipped from the grain boundary in terms of crystal structure.
- the melted portion 82 in which the nickel alloy and the noble metal are mixed has a relatively high hardness of 180 Hv or more (see FIG. 6), but has a property of being easily chipped from the grain boundary as compared with the noble metal.
- the tip gripping jig JG is moved to the intermediate member 81 and the melting portion. Since a sufficient contact portion for making contact with 82 can be ensured, it is possible to easily adjust the misalignment without touching the electrode chip 80 that is easily chipped.
- the upper limit of the distance L1 can be set to about 0.5 mm in consideration of the chip length defined as 0.5 to 1.2 mm in the above embodiment.
- the distance L2 from the tip surface of the electrode tip 80 to the upper end of the surface of the melted part 82 may be 0.1 mm or more.
- the melting part 82 has the property of being inferior in oxidation resistance and spark consumption resistance to the electrode tip 80. Therefore, when the electrode tip 80 and the intermediate member 81 are joined, if the melting portion 82 is included in the tip surface of the electrode tip 80, the portion may be selectively consumed. is there.
- the distance L2 from the tip surface of the electrode tip 80 to the upper end of the surface of the melted portion 82 is set to 0.1 mm or more, such consumption of the tip portion of the electrode tip 80 can be suppressed. It becomes possible.
- the upper limit of the distance L2 can be set to about 0.4 mm in consideration of the chip length defined as 0.5 to 1.2 mm in the above embodiment.
- the small diameter portion 84 is configured by a fibrous metal structure along a direction parallel to the axis O ′ of the electrode tip 80. It may be.
- the intermediate member 81 having such a fibrous structure can be generated by performing a wire drawing process on the metal material that is the base of the intermediate member 81. As described above, if the intermediate member 81 is formed of a fibrous metal structure along a direction parallel to the axis O ′ of the electrode tip 80, the stress applied to the intermediate member 81 when the axial deviation of the electrode tip 80 is corrected. The resistance to the can be increased. Therefore, the axial deviation of the electrode tip 80 can be corrected more appropriately.
- the intermediate member 81 is formed so as to have such a fibrous metal structure, when the spark plug 100 receives engine vibration, the intermediate member 81 can be prevented from being deformed by the vibration. It becomes possible. Such an effect becomes particularly prominent when the spark plug 100 is attached to a high-power or high-speed engine.
- the thin diameter portion 84 is formed by header processing, the portion near the lower end flange portion 83 in the small diameter portion 84 is not parallel to the axis O ′ of the electrode tip 80.
- the small diameter portion 84 is substantially constituted by a fibrous metal structure along a direction parallel to the axis O ′ of the electrode tip 80.
- the intermediate member 81 is composed of the narrow diameter portion 84 and the lower end flange portion 83.
- the formation of the lower end flange portion 83 may be omitted. That is, the intermediate member 81 may be formed in a full cylinder shape as a whole. In this case, it is preferable that the above-described fibrous metal structure is formed in at least a half portion of the intermediate member 81 on the melting portion 82 side.
- the entire intermediate member 81 may be constituted by a fibrous metal structure along a direction parallel to the axis O ′ of the electrode tip 80.
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Abstract
Description
Claims (13)
- 中心電極と、軸線方向に沿って延びる軸孔を有し、その軸孔内で前記中心電極を保持する絶縁体と、当該絶縁体を周方向に取り囲んで保持する主体金具と、基端部が前記主体金具に接合され、先端部が前記中心電極の先端部に対向するように前記基端部と前記先端部との間の中間部が屈曲された接地電極とを備え、該接地電極の前記先端部のうち前記中心電極の前記先端部と対向する位置に貴金属チップが配置され、前記中心電極の前記先端部と前記貴金属チップとの間に火花ギャップを形成するスパークプラグであって、
前記貴金属チップは、前記接地電極とは別体の中間部材の頂上面に接合されて前記中間部材と一体とされると共に、前記中間部材の底面が前記接地電極に接合されることにより、前記貴金属チップは前記接地電極に固着されており、
前記中間部材の平均硬度は、前記接地電極における前記中間部を除く部位の平均硬度より高い
スパークプラグ。 - 前記接地電極の平均硬度は、ビッカース硬度で180Hv未満である請求項1に記載のスパークプラグ。
- 前記中間部材の平均硬度は、ビッカース硬度で180Hv以上である請求項1または請求項2に記載のスパークプラグ。
- 請求項1ないし請求項3のいずれか一項に記載のスパークプラグであって、
前記中間部材は、前記接地電極側に太径部が形成され、前記貴金属チップ側に細径部が形成されており、前記太径部および前記細径部のうち少なくとも前記細径部は、前記貴金属チップの中心軸に略平行な方向に沿った繊維状の金属組織によって構成されている、スパークプラグ。 - 請求項1ないし請求項3のいずれか一項に記載のスパークプラグであって、
前記中間部材は、該中間部材のうちの前記貴金属チップ側の少なくとも半分の部分が、前記貴金属チップの中心軸に略平行な方向に沿った繊維状の金属組織によって構成されている、スパークプラグ。 - 請求項1ないし請求項5のいずれか一項に記載のスパークプラグであって、
前記中間部材と前記貴金属チップとの間に、該中間部材及び該貴金属チップが溶け合った溶融部が形成されている、スパークプラグ。 - 請求項6に記載のスパークプラグであって、
前記接地電極の前記中間部材が接合される面から、前記溶融部の表面における前記貴金属チップ側の端部までの距離が、0.3mm以上である、スパークプラグ。 - 請求項6または請求項7に記載のスパークプラグであって、
前記貴金属チップの先端面から前記溶融部の表面における前記貴金属チップ側の端部までの距離が、0.1mm以上である、スパークプラグ。 - 請求項6ないし請求項8のいずれか一項に記載のスパークプラグであって、
前記溶融部の平均硬度は、ビッカース硬度で180Hv以上である、スパークプラグ。 - 前記中間部材と前記接地電極とは、同じ組成比の合金材料から形成されている請求項1ないし請求項9のいずれか一項に記載のスパークプラグ。
- 前記貴金属チップは、白金(Pt)を主成分として、イリジウム(Ir)、ロジウム(Rh)、ニッケル(Ni)、タングステン(W)、パラジウム(Pd)、ルテニウム(Ru)、レニウム(Re)の少なくとも1種類の金属を含有して形成されている請求項1ないし請求項10のいずれか一項に記載のスパークプラグ。
- 請求項1ないし請求項11のいずれか一項に記載のスパークプラグであって、
前記中心電極の前記先端部には中心電極側貴金属チップが接合されており、該中心電極側貴金属チップは前記貴金属チップと対向している、スパークプラグ。 - 前記中心電極側貴金属チップは、イリジウム(Ir)を主成分として、白金(Pt)、ロジウム(Rh)、ニッケル(Ni)、タングステン(W)、パラジウム(Pd)、ルテニウム(Ru)、レニウム(Re)、アルミニウム(Al)、酸化アルミニウム(Al2O3)、イットリウム(Y)、酸化イットリウム(Y2O3)の少なくとも1種類の金属を含有して形成されている請求項12に記載のスパークプラグ。
Priority Applications (4)
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EP09734460.0A EP2270937B1 (en) | 2008-04-24 | 2009-04-23 | Spark plug |
US12/989,586 US8129891B2 (en) | 2008-04-24 | 2009-04-23 | Spark plug |
JP2009540532A JP5185949B2 (ja) | 2008-04-24 | 2009-04-23 | スパークプラグ |
CN200980114425.2A CN102017340B (zh) | 2008-04-24 | 2009-04-23 | 火花塞 |
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JP2008113422 | 2008-04-24 |
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PCT/JP2009/001867 WO2009130909A1 (ja) | 2008-04-24 | 2009-04-23 | スパークプラグ |
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US (1) | US8129891B2 (ja) |
EP (1) | EP2270937B1 (ja) |
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JP2012089353A (ja) * | 2010-10-20 | 2012-05-10 | Denso Corp | 内燃機関用のスパークプラグ |
US8994257B2 (en) | 2012-02-28 | 2015-03-31 | Denso Corporation | Spark plug for internal combustion engine and method for manufacturing same |
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WO2009084565A1 (ja) * | 2007-12-27 | 2009-07-09 | Ngk Spark Plug Co., Ltd. | スパークプラグ |
CN103229372A (zh) | 2010-07-29 | 2013-07-31 | 美国辉门(菲德尔莫古)点火系统有限公司 | 用于与火花塞一起使用的电极材料 |
JP5301035B2 (ja) * | 2010-12-24 | 2013-09-25 | 日本特殊陶業株式会社 | スパークプラグ |
US8471451B2 (en) | 2011-01-05 | 2013-06-25 | Federal-Mogul Ignition Company | Ruthenium-based electrode material for a spark plug |
CN103354965B (zh) * | 2011-02-15 | 2015-05-13 | 日本特殊陶业株式会社 | 火花塞 |
DE112012000947B4 (de) | 2011-02-22 | 2018-03-22 | Federal-Mogul Ignition Company | Verfahren zum Herstellen eines Elektrodenmaterials für einen Zündkerze |
DE112012002699B4 (de) | 2011-06-28 | 2018-12-13 | Federal-Mogul Ignition Company | Zündkerze und Verfahren zum Herstellen einer Elektrode einer Zündkerze |
US10044172B2 (en) | 2012-04-27 | 2018-08-07 | Federal-Mogul Ignition Company | Electrode for spark plug comprising ruthenium-based material |
DE112013002619B4 (de) | 2012-05-22 | 2018-12-27 | Federal-Mogul Ignition Company | Verfahren zum Herstellen eines Elektrodenmaterials |
US8979606B2 (en) | 2012-06-26 | 2015-03-17 | Federal-Mogul Ignition Company | Method of manufacturing a ruthenium-based spark plug electrode material into a desired form and a ruthenium-based material for use in a spark plug |
JP5990216B2 (ja) * | 2014-05-21 | 2016-09-07 | 日本特殊陶業株式会社 | スパークプラグ |
JP6328158B2 (ja) * | 2016-01-26 | 2018-05-23 | 日本特殊陶業株式会社 | スパークプラグ |
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 |
DE112020001828T5 (de) | 2019-04-11 | 2021-12-23 | Federal-Mogul Ignition Llc | Zündkerzengehäuse und verfahren zur herstellung |
JP2023069392A (ja) * | 2021-11-05 | 2023-05-18 | 株式会社デンソー | スパークプラグの接地電極、スパークプラグ |
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- 2009-04-23 KR KR1020107026104A patent/KR101215668B1/ko active IP Right Grant
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US8994257B2 (en) | 2012-02-28 | 2015-03-31 | Denso Corporation | Spark plug for internal combustion engine and method for manufacturing same |
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CN102017340B (zh) | 2013-06-12 |
JP5185949B2 (ja) | 2013-04-17 |
CN102017340A (zh) | 2011-04-13 |
JPWO2009130909A1 (ja) | 2011-08-11 |
EP2270937A4 (en) | 2013-07-24 |
KR20100135302A (ko) | 2010-12-24 |
EP2270937B1 (en) | 2016-06-08 |
KR101215668B1 (ko) | 2012-12-26 |
EP2270937A1 (en) | 2011-01-05 |
US20110043093A1 (en) | 2011-02-24 |
US8129891B2 (en) | 2012-03-06 |
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