WO2015111634A1 - Spark plug - Google Patents
Spark plug Download PDFInfo
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- WO2015111634A1 WO2015111634A1 PCT/JP2015/051569 JP2015051569W WO2015111634A1 WO 2015111634 A1 WO2015111634 A1 WO 2015111634A1 JP 2015051569 W JP2015051569 W JP 2015051569W WO 2015111634 A1 WO2015111634 A1 WO 2015111634A1
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- WIPO (PCT)
- Prior art keywords
- ground electrode
- metal shell
- boundary
- outer layer
- spark plug
- Prior art date
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
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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
- H01T13/32—Sparking plugs characterised by features of the electrodes or insulation characterised by features of the earthed electrode
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
Definitions
- This disclosure relates to a spark plug.
- spark plugs have been used in internal combustion engines.
- the spark plug has an electrode that forms a gap.
- an electrode for example, a ground electrode having a coating material excellent in oxidation resistance and a core material that has better thermal conductivity than the coating material and is enclosed inside the coating material has been proposed. If such a ground electrode is employed, the oxidation resistance can be improved by lowering the temperature of the ground electrode.
- the bonding strength when the ground electrode is bonded to the metal shell, the bonding strength may be low.
- the bonding strength between the covering material and the metal shell may be low.
- This disclosure discloses a technique for improving the bonding strength between the ground electrode and the metal shell.
- a spark plug comprising: The ground electrode is Forming at least a part of the surface of the ground electrode, bonded to the metal shell, and an outer layer formed of a material containing nickel as a main component and aluminum in an amount of more than 0 wt% to 2.5 wt%; A core portion disposed on the inner peripheral side of the outer layer; Including The amount of oxygen on the surface of the outer layer is more than 0 wt% and 8 wt% or less,
- the core includes a first layer formed of copper or a material containing copper as a main component, At the base end portion of the ground electrode having a cross section including the center axis of the spark plug and the center axis of the ground electrode, at least one of two boundary lines representing a
- the bonding strength between the outer layer and the metal shell can be improved as compared with the case where the oxygen amount exceeds 8 wt%.
- at least one of the two boundary lines representing the boundary between the outer layer and the core portion in the cross section includes an inclined line extending obliquely from the end on the metal shell side toward the outer peripheral side, the outer layer, the metal shell, The bonding area can be increased. As a result, the bonding strength between the ground electrode and the metal shell can be improved.
- the boundary lines including the inclined line, a straight line passing through the boundary end parallel to the central axis of the ground electrode, and the outer periphery located in a direction in which the inclined line extends when viewed from the boundary end
- the total distance between the straight line passing through the end and parallel to the central axis of the ground electrode is a junction distance W1
- the ratio t is greater than 0% and not greater than 80%. Spark plug.
- the bonding strength between the outer layer and the metal shell can be further improved. Further, since the ratio t of the joint distance W1 to the total distance W2 is greater than 0% and 80% or less, the joint strength between the ground electrode and the metal shell can be further improved.
- the spark plug according to application example 1 The core portion is further arranged in part on the inner peripheral side of the first layer, and is formed of a material containing nickel with a larger content (% by weight) than the outer layer, and is more thermally conductive than the outer layer.
- Including a second layer with a high rate In the base end of the ground electrode of the cross section, The end on the metal shell side of the inclined line is a boundary end, The distance in the direction perpendicular to the central axis of the ground electrode between the two outer peripheral ends that are the ends on the metal shell side of each of the two outer peripheral lines representing the outer peripheral surface of the outer layer is defined as a total distance W2.
- the boundary lines including the inclined line, a straight line passing through the boundary end parallel to the central axis of the ground electrode, and the outer periphery located in a direction in which the inclined line extends when viewed from the boundary end
- the total distance between the straight line passing through the end and parallel to the central axis of the ground electrode is a junction distance W1
- the ratio t is greater than 0% and not greater than 20%. Spark plug.
- the bonding strength between the ground electrode and the metal shell can be further improved.
- the metal shell is separated from the first layer and is bonded to the outer layer and the second layer, the bonding strength between the ground electrode and the metal shell can be further improved.
- the bonding area between the outer layer and the metal shell can be increased as compared with the case where only one of the two boundary lines includes an inclined line, the bonding between the ground electrode and the metal shell can be performed. Strength can be improved.
- the technology disclosed in the present specification can be realized in various modes, for example, in a mode such as a spark plug, an internal combustion engine equipped with a spark plug, a method for manufacturing a spark plug, and the like. it can.
- FIG. 3 is a cross-sectional view of a joint portion between a ground electrode 30 and a metal shell 50.
- FIG. It is the schematic which shows an example of a joining process.
- FIG. 1 is a cross-sectional view of an example of a spark plug according to the first embodiment.
- the illustrated line CL indicates the central axis of the spark plug 100.
- the illustrated cross section is a cross section including the central axis CL.
- the central axis CL is also referred to as “axis line CL”
- the direction parallel to the central axis CL is also referred to as “axis line direction”.
- the radial direction of the circle centered on the central axis CL is also simply referred to as “radial direction”
- the circumferential direction of the circle centered on the central axis CL is also referred to as “circumferential direction”.
- the upper direction in FIG. 1 is referred to as a front end direction D1
- the lower direction is also referred to as a rear end direction D1r.
- the tip direction D1 is a direction from the terminal fitting 40 described later toward the electrodes 20 and 30. 1 is referred to as the front end side of the spark plug 100, and the rear end direction D1r side in FIG. 1 is referred to as the rear end side of the spark plug 100.
- the spark plug 100 includes an insulator 10 (hereinafter also referred to as “insulator 10”), a center electrode 20, a ground electrode 30, a terminal metal fitting 40, a metal shell 50, a conductive first seal portion 60, A resistor 70, a conductive second seal portion 80, a front end side packing 8, a talc 9, a first rear end side packing 6, and a second rear end side packing 7 are provided.
- insulator 10 insulator 10
- the insulator 10 is a substantially cylindrical member having a through-hole 12 (hereinafter also referred to as “shaft hole 12”) extending along the central axis CL and penetrating the insulator 10.
- the insulator 10 is formed by firing alumina (other insulating materials can also be used).
- the insulator 10 includes a leg portion 13, a first reduced outer diameter portion 15, a distal end side body portion 17, a flange portion 19, and a second reduced outer diameter that are arranged in order from the front end side toward the rear end direction D1r. Part 11 and rear end side body part 18.
- the outer diameter of the first reduced outer diameter portion 15 gradually decreases from the rear end side toward the front end side.
- a reduced inner diameter portion 16 whose inner diameter gradually decreases from the rear end side toward the front end side is formed.
- the outer diameter of the second reduced outer diameter portion 11 gradually decreases from the front end side toward the rear end side.
- a rod-shaped center electrode 20 extending along the center axis CL is inserted on the tip end side of the shaft hole 12 of the insulator 10.
- the center electrode 20 includes a leg portion 25, a flange portion 24, and a head portion 23 that are arranged in order from the front end side toward the rear end direction D1r.
- a portion on the distal end side of the leg portion 25 is exposed outside the shaft hole 12 on the distal end side of the insulator 10.
- the surface of the flange portion 24 on the distal direction D1 side is supported by the reduced inner diameter portion 16 of the insulator 10.
- the center electrode 20 has an outer layer 21 and a core portion 22.
- the rear end portion of the core portion 22 is exposed from the outer layer 21 and forms the rear end portion of the center electrode 20.
- the other part of the core part 22 is covered with the outer layer 21. However, the entire core portion 22 may be covered with the outer layer 21.
- the outer layer 21 is formed using a material that is more excellent in oxidation resistance than the core portion 22, that is, a material that consumes less when exposed to combustion gas in the combustion chamber of the internal combustion engine.
- a material that is more excellent in oxidation resistance than the core portion 22 that is, a material that consumes less when exposed to combustion gas in the combustion chamber of the internal combustion engine.
- the material of the outer layer 21 for example, nickel (Ni) or an alloy containing nickel as a main component (for example, Inconel ("INCONEL" is a registered trademark)) is used.
- the “main component” means a component having the highest content (hereinafter the same).
- wt%) a value represented by weight percent (wt%) is adopted.
- the core portion 22 is formed of a material having a higher thermal conductivity than the outer layer 21, for example, a material containing copper (for example, pure copper or an alloy containing copper as a main component).
- a terminal fitting 40 is inserted on the rear end side of the shaft hole 12 of the insulator 10.
- the terminal fitting 40 is formed using a conductive material (for example, a metal such as low carbon steel).
- a columnar resistor 70 for suppressing electrical noise is disposed between the terminal fitting 40 and the center electrode 20.
- a conductive first seal portion 60 is disposed between the resistor 70 and the center electrode 20, and a conductive second seal portion 80 is disposed between the resistor 70 and the terminal fitting 40. Yes.
- the center electrode 20 and the terminal fitting 40 are electrically connected through the resistor 70 and the seal portions 60 and 80.
- the metallic shell 50 is a substantially cylindrical member having a through hole 59 extending along the central axis CL and penetrating the metallic shell 50 (in this embodiment, the central axis of the metallic shell 50 is the center of the spark plug 100). Coincides with the axis CL).
- the metal shell 50 is formed using a low carbon steel material (other conductive materials (for example, metal materials) can also be used).
- the insulator 10 is inserted into the through hole 59 of the metal shell 50.
- the metal shell 50 is fixed to the outer periphery of the insulator 10.
- the distal end of the insulator 10 on the distal end side of the metal shell 50, the distal end of the insulator 10 (in this embodiment, the portion on the distal end side of the leg portion 13) is exposed outside the through hole 59.
- the rear end of the insulator 10 (in this embodiment, the portion on the rear end side of the rear end side body portion 18) is exposed outside the through hole 59.
- the metal shell 50 includes a body portion 55, a seat portion 54, a deformation portion 58, a tool engaging portion 51, and a caulking portion 53, which are arranged in order from the front end side to the rear end side. Yes.
- the seat part 54 is a bowl-shaped part.
- a screw portion 52 for screwing into a mounting hole of an internal combustion engine for example, a gasoline engine
- An annular gasket 5 formed by bending a metal plate is fitted between the seat portion 54 and the screw portion 52.
- the metal shell 50 has a reduced inner diameter portion 56 disposed on the distal direction D1 side with respect to the deformable portion 58.
- the inner diameter of the reduced inner diameter portion 56 gradually decreases from the rear end side toward the front end side.
- the front end packing 8 is sandwiched between the reduced inner diameter portion 56 of the metal shell 50 and the first reduced outer diameter portion 15 of the insulator 10.
- the front end packing 8 is an iron-shaped O-shaped ring (other materials (for example, metal materials such as copper) can also be used).
- the shape of the tool engaging portion 51 is a shape (for example, a hexagonal column) with which a spark plug wrench is engaged.
- a caulking portion 53 is provided on the rear end side of the tool engaging portion 51.
- the caulking portion 53 is disposed on the rear end side of the second reduced outer diameter portion 11 of the insulator 10 and forms the rear end (that is, the end on the rear end direction D1r side) of the metal shell 50.
- the caulking portion 53 is bent toward the inner side in the radial direction.
- the first rear end side packing 6, the talc 9, and the second rear end side are provided between the inner peripheral surface of the metal shell 50 and the outer peripheral surface of the insulator 10.
- the packings 7 are arranged in this order toward the tip direction D1. In this embodiment, these rear end side packings 6 and 7 are iron-made C-shaped rings (other materials are also employable).
- the crimping portion 53 is crimped so as to be bent inward. And the crimping part 53 is pressed to the front end direction D1 side. Thereby, the deformation
- the front end side packing 8 is pressed between the first reduced outer diameter portion 15 and the reduced inner diameter portion 56 and seals between the metal shell 50 and the insulator 10.
- the metal shell 50 is fixed to the insulator 10.
- the ground electrode 30 is a rod-like electrode having a substantially rectangular cross section.
- the end surface 37 of one end portion 30x of the ground electrode 30 is joined to the end surface 57 of the end portion 50x on the front end direction D1 side of the metal shell 50.
- the end portion 30x of the ground electrode 30 is referred to as a “base end portion 30x”
- the end surface 37 of the base end portion 30x is referred to as a “base end surface 37”.
- the end portion 50x of the metal shell 50 is referred to as a “tip portion 50x”
- the end surface 57 of the tip portion 50x is referred to as a “tip surface 57”.
- the base end surface 37 and the front end surface 57 are both substantially perpendicular to the central axis CL of the metal shell 50.
- the ground electrode 30 extends from the distal end surface 57 of the metal shell 50 toward the distal end direction D1, bends toward the central axis CL, and reaches the distal end portion 31.
- the distal end portion 31 forms a gap g between the distal end surface 29 of the central electrode 20 (surface 29 on the distal end direction D1 side).
- the ground electrode 30 has an outer layer 35 that forms at least a part of the surface of the ground electrode 30, and a core portion 36 embedded in the outer layer 35.
- the base end portion 30x of the ground electrode 30 is a portion closer to the metal shell 50 than the bent portion 38 of the ground electrode 30.
- FIG. 2 is a schematic view of the spark plug 100 as viewed from the front end side.
- the center electrode 20, the insulator 10, and the metal shell 50 are arranged on the same axis with the center axis CL as the center.
- the ground electrode 30 is joined to the front end surface 57 of the metal shell 50.
- a wide portion 350 that is wide at the time of welding is formed at a joint portion between the base end surface 37 of the ground electrode 30 and the front end surface 57 of the metal shell 50.
- the wide portion 350 is formed by at least one of melting and deformation of at least one of the ground electrode 30 and the metal shell 50.
- FIG. 3 is a cross-sectional view of a joint portion between the ground electrode 30 and the metal shell 50.
- This sectional view is a section in a plane P1 including the central axis CL (FIG. 2) of the metal shell 50 and the central axis CLx of the ground electrode 30.
- a cross section including the two central axes CL and CLx is referred to as a “reference cross section”.
- the right direction Di is a direction toward the inside of the radial direction (hereinafter referred to as “inward direction Di”)
- the left direction Do is a direction toward the outside of the radial direction (hereinafter referred to as “outward direction Do”). It is.
- the central axis CLx of the ground electrode 30 is a rod-shaped central axis of the ground electrode 30. As shown in FIG. 3, the central axis CLx is not the bent portion 38 of the ground electrode 30, but the base end portion 30x (particularly, the portion 30s (hereinafter referred to as “the original shape without being deformed during welding”). As shown in FIG. 2, when viewed from the central axis CL of the metal shell 50, the central axis CLx is the circumference of the ground electrode 30 (particularly, the maintenance portion 30s). It is located in the central direction obtained by equally dividing the angle range AR from one end 301 to the other end 302.
- the central axis CLx is the same as the central axis CL of the metal shell 50, 2
- the first width Wa indicates the length of the first side Sa having a substantially rectangular shape in the cross section of the ground electrode 30, and the second width Wb is approximately the cross section of the ground electrode 30.
- the length of the second side Sb orthogonal to the rectangular first side Sa is shown.
- the first side Sa is substantially perpendicular to the plane P1, is bisected by the plane P1.
- the ground electrode 30 includes an outer layer 35 and a core portion 36.
- the outer layer 35 forms the surface of the ground electrode 30 and is joined to the metal shell 50.
- the outer layer 35 is formed of a material that has better oxidation resistance than the core portion 36.
- the outer layer 35 is formed of a material containing nickel, chromium, and aluminum as main components, specifically, a nickel chromium alloy to which aluminum is added.
- oxidation resistance can be improved by adding aluminum to a nickel chromium alloy.
- the core portion 36 is disposed on the inner peripheral side of the outer layer 35 and is joined to the metal shell 50.
- the core part 36 is formed of a material having a higher thermal conductivity than the outer layer 35. In the present embodiment, the core portion 36 is formed using pure copper.
- the two boundary lines L10 and L20 in the figure represent the boundary between the outer layer 35 and the core part 36.
- the first boundary line L10 indicates the boundary line on the inner direction Di side
- the second boundary line L20 indicates the boundary line on the outer direction Do side.
- the first boundary end P11 is an end of the first boundary line L10 on the metal shell 50 side.
- the second boundary end P21 is an end of the second boundary line L20 on the metal shell 50 side.
- the two outer peripheral lines L30 and L40 in the figure represent the outer peripheral surface of the outer layer 35.
- the first outer peripheral line L30 indicates the outer peripheral line on the inner direction Di side
- the second outer peripheral line L40 indicates the outer peripheral line on the outer direction Do side.
- the first outer peripheral end P32 is an end of the first outer peripheral line L30 on the metal shell 50 side.
- the second outer peripheral end P42 is an end of the second outer peripheral line L40 on the metal shell 50 side.
- the two boundary lines L10 and L20 are approximately parallel to the central axis CLx in the maintenance portion 30s.
- the second boundary line L20 is curved so as to be farther from the central axis CLx as it is closer to the metal shell 50, and reaches the second boundary end P21. The reason why such a second boundary line L20 can be formed will be described later.
- the first boundary line L10 is curved in the same manner as the second boundary line L20 in the portion of the wide portion 350 close to the maintenance portion 30s. However, in the portion of the wide portion 350 close to the metal shell 50, the first boundary line L10 is curved so as to be closer to the central axis CLx as it is closer to the metal shell 50, and reaches the first boundary end P11. In other words, the first boundary line L10 is inclined from the first boundary end P11 to the outer peripheral side of the portion of the outer layer 35 that forms the first boundary line L10, obliquely with respect to the central axis CLx of the ground electrode 30. An inclined portion L11 extending in the direction is included. Thus, on the inner direction Di side of the ground electrode 30, the outer layer 35 extends toward the central axis CLx along the distal end surface 57 of the metal shell 50. Therefore, the joint area between the outer layer 35 and the metal shell 50 increases.
- the welding area between the ground electrode 30 and the metal shell 50 can be improved by increasing the joint area between the outer layer 35 and the metal shell 50.
- the reason for this is as follows.
- the thermal conductivity of copper is higher than that of nickel alloys. That is, copper is more likely to release heat than a nickel alloy. Therefore, at the time of welding the ground electrode 30 and the metal shell 50, the temperature of copper (that is, the core portion 36) tends to be lower than the temperature of the nickel alloy (that is, the outer layer 35) at the joint surface.
- the bonding strength between the core portion 36 and the metal shell 50 can be lower than the bonding strength between the outer layer 35 and the metal shell 50. Therefore, when the ratio of the bonding area between the outer layer 35 and the metal shell 50 on the bonding surface is large, the bonding strength between the ground electrode 30 and the metal shell 50 can be improved as compared with the case where the ratio is small.
- FIG. 4 is a schematic diagram illustrating an example of a bonding process.
- the joining process proceeds in the order of FIG. 4 (A) to FIG. 4 (F).
- a part of the ground electrode 30 (part joined to the metal shell 50) and a part of the metal shell 50 (part joined to the ground electrode 30) are shown.
- a reference cross section (cross section in the plane P1) similar to that in FIG. 3 is shown.
- one end of the ground electrode 30 is cut to form a base end face 37.
- the boundary lines L10u and L20u in the figure correspond to the boundary lines L10 and L20 (FIG. 3) before joining, respectively, and the outer peripheral lines L30u and L40u correspond to the outer peripheral lines L30 and L40 before joining, respectively.
- Each of the lines L10u, L20u, L30u, and L40u is parallel to the central axis CLx.
- the ground electrode 30 is sheared by moving the cutting blade 920 in a direction perpendicular to the central axis CLx with respect to the ground electrode 30 supported by the support 910.
- the cutting blade 920 moves from the inner direction Di side of the ground electrode 30 toward the outer direction Do.
- a cut surface formed by this cutting corresponds to the base end surface 37.
- FIG. 4C shows the ground electrode 30 after cutting.
- each element of the ground electrode 30 here, the outer layer 35 and the core portion 36
- the first boundary line L10u is deformed so that the closer to the base end surface 37, the closer to the central axis CLx.
- the ground electrode 30 is disposed on the front end surface 57 of the metal shell 50.
- the proximal end surface 37 of the ground electrode 30 contacts a predetermined portion on the distal end surface 57 of the metal shell 50.
- the ground electrode 30 and the metal shell 50 are joined by resistance welding.
- a force parallel to the central axis CLx is applied to the ground electrode 30 and the metal shell 50.
- a force in the direction toward the metal shell 50 (rear end direction D1r) is applied to the ground electrode 30, and a force in the front end direction D1 is applied to the metal shell 50.
- FIG. 4 (E) shows an example of a cross-sectional view after welding.
- the distal end portion 50x of the metal shell 50 extends along the base end surface 37 of the ground electrode 30 in a direction perpendicular to the central axis CLx.
- the base end portion 30x of the ground electrode 30 extends in the direction perpendicular to the central axis CLx along the distal end surface 57 of the metal shell 50.
- the base end portion 30x and the tip end portion 50x can be deformed as shown in FIG. 4E by the force applied during welding.
- the core portion 36 Since the core portion 36 is pressed against the distal end surface 57 of the metal shell 50 during welding, the core portion 36 is deformed so as to expand along the distal end surface 57 in a direction away from the central axis CLx. As a result, after welding, the second boundary line L20 can be formed so as to be farther from the central axis CLx as it is closer to the distal end surface 57.
- the first boundary line L10 is as follows. As described with reference to FIG. 4C, the boundary line L10u before welding is formed in the vicinity of the base end face 37 so as to be closer to the central axis CLx as it is closer to the base end face 37.
- the core portion 36 is difficult to expand in the vicinity of the first boundary line L10u, and the outer layer 35 can expand toward the central axis CLx.
- the first boundary end P11 of the first boundary line L10 can be formed at a position closer to the central axis CLx than the second boundary end P21 of the second boundary line L20.
- FIG. 4F shows a state where the bonding is completed, which is the same as the cross-sectional view of FIG.
- the first reference surface Si is substantially the same as a surface obtained by extending the inner peripheral surface of the metal shell 50 (the inner peripheral surface before welding in the vicinity of the front end surface 57) in the front end direction D1.
- the portions 35o and 50o on the outer direction Do side than the second reference plane So are removed.
- the second reference surface So is approximately the same as a surface obtained by extending the outer peripheral surface of the metal shell 50 (the outer peripheral surface before welding near the front end surface 57) in the front end direction D1.
- ground electrode 30 various methods can be adopted. For example, the following method can be employed. A cup-shaped outer member formed of the material of the outer layer 35 is prepared, and the inner member formed of the material of the core portion 36 is inserted into the outer member. A rod-shaped member having an inner member and an outer member covering the inner member, that is, a ground electrode before bending, is formed by molding the outer shape of the outer member with the inner member inserted. The obtained rod-shaped ground electrode is joined to the metal shell 50 according to the procedure described in FIG. Then, the ground electrode 30 is formed by bending the ground electrode so that an appropriate gap g is formed. In order to make the ground electrode 30 easy to bend, the rod-shaped ground electrode before bending may be annealed.
- the joining of the ground electrode 30 and the metal shell 50 can be performed at various stages in the process of manufacturing the spark plug 100. For example, after the metal shell 50 is fixed to the insulator 10 that holds the center electrode 20 and the terminal metal fitting 40, a bar-shaped ground electrode before bending may be joined to the metal shell 50. Then, after this joining, the ground electrode may be bent so as to form an appropriate gap g. Instead, the metal shell 50 may be fixed to the insulator 10 holding the center electrode 20 and the terminal metal fitting 40 after the bar-shaped ground electrode before bending is joined to the metal shell 50.
- “Surface oxygen content” is the oxygen content in the surface of the outer layer 35 of the ground electrode 30 before welding (unit: weight percent).
- the method for measuring the surface oxygen amount is as follows. The kind and amount of elements on the surface of the outer layer 35 of the portion different from the portion that melts or deforms during welding in the ground electrode 30 before welding were analyzed by electron beam microanalysis (EPMA). . The analyzed area was a 500 ⁇ m ⁇ 500 ⁇ m square area. Then, the ratio of the amount of the oxygen element to the total amount of the elements constituting the outer layer 35 and the oxygen element was calculated as the surface oxygen amount.
- SEM / EDS scanning electron microscope / energy dispersive X-ray analyzer
- JSM-6490LA manufactured by JEOL Ltd.
- the acceleration voltage was set to 20 kV.
- the elements on the surface of the ground electrode 30 can be oxidized by oxygen contained in an environmental gas (for example, air) surrounding the ground electrode 30.
- an environmental gas for example, air
- the outer layer 35 includes aluminum
- the surface of the outer layer 35 that is, the surface of the ground electrode 30 is easily oxidized.
- the above-described annealing is performed, the amount of surface oxide can be increased. Such oxides can cause weld defects. Therefore, when the amount of oxygen on the surface is large, the welding strength may be reduced.
- the amount of surface oxygen was adjusted by adjusting the annealing temperature and the annealing time.
- the method for controlling the surface oxygen amount is not limited to the method of adjusting the annealing temperature and time, and various methods can be adopted. For example, the oxygen concentration in the environmental gas during annealing may be adjusted. Further, in order to reduce the amount of surface oxygen, annealing may be performed in a container evacuated by a vacuum pump.
- “Proportion t” in Table 1 is the ratio of the joining distance W1 to the total distance W2 shown in FIG. 3 (unit:%).
- the total distance W2 is in the direction perpendicular to the central axis CLx of the ground electrode 30 between the outer peripheral ends P32 and P42 of the two outer peripheral lines L30 and L40 on the metal shell 50 side in the reference cross section shown in FIG. Distance.
- the joining distance W1 is a straight line LP1 passing through the boundary end P11 on the metal shell 50 side of the inclined portion L11 and parallel to the central axis CLx of the ground electrode 30, and the outer peripheral end positioned in the extending direction of the inclined portion L11 when viewed from the boundary end P11.
- the junction distance W1 is a distance in a direction perpendicular to the central axis CLx of the ground electrode 30.
- the second boundary line L20 is inclined from the boundary end P21 of the second boundary line L20 to the outer peripheral side of the portion of the outer layer 35 that forms the second boundary line L20, obliquely with respect to the central axis CLx of the ground electrode 30. It does not include an inclined part that extends. Therefore, the distance between the boundary end P21 of the second boundary line L20 and the second outer peripheral end P42 of the second outer peripheral line L40 is not included in the joint distance W1.
- the strength evaluation results in Table 1 were determined as follows. That is, a tensile test was performed by pulling the ground electrode 30 and the metal shell 50 in directions away from each other parallel to the central axis CLx, and the tensile strength (that is, the maximum tensile load that the sample can withstand) was measured. A rating indicates that tensile strength is 450 N / mm 2 or more, B rating is a tensile strength of 350 N / mm 2 or more, the tensile strength showed to be less than 450 N / mm 2, C rating, tensile The strength is less than 350 N / mm 2 . The tensile test was performed using AG-5000B manufactured by Shimadzu Corporation.
- the measurement of the ratio t and the tensile test were performed using a plurality of samples manufactured under the same conditions.
- a ratio t measured by cutting a sample manufactured under the same conditions at the reference cross section was adopted.
- the proportion t was approximately the same among the samples made under the same conditions.
- First width Wa (FIG. 2) of the cross section of the ground electrode 30: 2.8 mm
- Second width Wb (FIG. 2) of the cross section of the ground electrode 30: 1.5 mm
- Material of outer layer 35 Inconel 601
- Aluminum content of outer layer 35 1.4 wt%
- Material of core part 36 pure copper
- the strength evaluation result was C evaluation regardless of the ratio t.
- the surface oxygen amount was 8 wt% or less, it was possible to realize a better evaluation result (A evaluation or B evaluation).
- the welding strength could be improved by suppressing the surface oxygen amount to 8 wt% or less.
- achieve a favorable evaluation result was 1, 2, 4, 5, 8 (wt%). Any value among these values can be adopted as the upper limit of the preferable range (more than the lower limit and less than the upper limit) of the surface oxygen amount. For example, a value of 8 wt% or less can be adopted as the surface oxygen amount. Moreover, any value below the upper limit among these values can be adopted as the lower limit of the preferable range of the surface oxygen amount. For example, a value of 1 wt% or more can be adopted as the surface oxygen amount.
- the surface oxygen amount was 5 wt% or less, particularly good A evaluation could be realized.
- achieve A evaluation was 1, 2, 4, 5 (wt%). Therefore, it is particularly preferable to select the upper limit and the lower limit of the preferable range of the surface oxygen amount from these four values.
- the ratio t at which A was obtained was 5, 10, 30, 50, and 80 (%). Any value among these values can be adopted as the upper limit of the preferable range of the ratio t. For example, a value of 80% or less can be adopted as the ratio t.
- the ratio t is larger than zero%, it is estimated that welding strength can be improved rather than the case where the ratio t is zero%.
- ratio t various values larger than zero% can be adopted as the ratio t. Moreover, you may select the minimum of the ratio t from the ratio t (5, 10, 30, 50, 80 (%)) from which A evaluation was obtained. For example, a value of 5% or more may be adopted as the ratio t.
- FIG. 5 is a cross-sectional view of an example of the spark plug according to the second embodiment.
- FIG. 3 a cross-sectional view of a joint portion between the base end portion 30bx of the ground electrode 30b and the tip end portion 50x of the metal shell 50 is shown.
- the core portion 36b of the ground electrode 30b includes the first layer 34a and the second layer 34b disposed on the inner peripheral side of the first layer 34a. It is.
- the configuration other than the core portion 36b is the same as the configuration of the ground electrode 30 shown in FIG.
- the configuration of the spark plug 100b of the second embodiment other than the ground electrode 30b is the same as the configuration of the spark plug 100 shown in FIG.
- the first layer 34a is formed of a material having a higher thermal conductivity than the outer layer 35, like the core portion 36 of FIG. In the present embodiment, the first layer 34a is formed using pure copper. A part of the second layer 34b is disposed on the inner peripheral side of the first layer 34a.
- the second layer 34b is formed of a material containing nickel with a larger content rate (wt%) than the outer layer 35. That is, the nickel content of the second layer 34 b is higher than the nickel content of the outer layer 35. Further, the thermal conductivity of the second layer 34 b is higher than the thermal conductivity of the outer layer 35. In the present embodiment, the second layer 34b is formed using pure nickel.
- the internal structure of the ground electrode 30b is a two-layer structure including an outer layer 35 and a second layer 34b in a part including the base end face 37, and the outer layer 35 and the first layer 34a in the other part. And a second layer 34b.
- the first layer 34 a is not joined to the metal shell 50
- the second layer 34 b is joined to the metal shell 50.
- the internal structure of the tip portion of the ground electrode 30b (the portion corresponding to the tip portion 31 in FIG. 1) is also a two-layer structure of the outer layer 35 and the second layer 34b.
- the first layer 34a may extend to the tip of the ground electrode 30b.
- the boundary lines L10b and L20b in the figure represent the boundary between the outer layer 35 and the core part 36b, respectively, similarly to the boundary lines L10 and L20 in FIG.
- the boundary ends P11b and P21b are the ends on the metal shell 50 side of the boundary lines L10b and L20b, respectively, similarly to the boundary ends P11 and P21 of FIG.
- the boundary line L10b is, like the first boundary line L10 in FIG. 3, obliquely from the first boundary end P11b to the central axis CLx of the ground electrode 30b, and is the first boundary of the outer layer 35.
- An inclined portion L11b extending toward the outer peripheral side of the portion forming the line L10b is included.
- the ground electrode 30b and the metal shell 50 are compared with the case where the first layer 34a is joined to the metal shell 50 without forming the inclined portion L11b.
- the welding strength can be improved.
- the welding strength of nickel is stronger than copper.
- the first layer 34 a containing copper is separated from the metal shell 50.
- the outer layer 35 containing nickel and the second layer 34 b are joined to the metal shell 50. Therefore, compared with the case where the first layer 34a is joined to the metal shell 50, the welding strength between the ground electrode 30b and the metal shell 50 can be improved.
- a method for forming the joint portion as shown in FIG. 5 a method similar to the method described in FIGS. 4 (A) to 4 (F) can be employed.
- various methods can be adopted. For example, a member having a three-layer structure portion of the outer layer 35, the first layer 34a, and the second layer 34b and a two-layer structure portion of the outer layer 35 and the second layer 34b as the ground electrode 30b before cutting. To manufacture. Next, the portion having the two-layer structure is cut in the same manner as in FIGS. 4A and 4B. Next, the base end face 37b and the front end face 57 of the metal shell 50 are welded in the same manner as in FIGS. 4D and 4E. And the joining process is completed by removing the part which protruded from the reference plane Si and So (FIG.4 (E)) similarly to FIG.4 (E) and FIG.4 (F).
- the same method as the manufacturing method of the ground electrode 30 of 1st Embodiment is employable.
- a method for manufacturing the spark plug 100b a method similar to the method for manufacturing the spark plug 100 of the first embodiment can be employed.
- the ratio t is a ratio of the joining distance W1 to the total distance W2 shown in FIG. 5 (unit:%).
- the total distance W2 is the same as the total distance W2 of the embodiment of FIG.
- the junction distance W1 is a distance between the two straight lines LP1b and LP3.
- the straight line LP3 is the same as the straight line LP3 in FIG.
- the straight line LP1b is a straight line that passes through the boundary end P11b on the metal shell 50 side of the inclined portion L11b and is parallel to the central axis CLx of the ground electrode 30b.
- the second boundary line L20b is inclined from the boundary end P21b of the second boundary line L20b with respect to the central axis CLx of the ground electrode 30b toward the outer peripheral side of the portion of the outer layer 35 that forms the second boundary line L20b. It does not include an inclined part that extends. Therefore, the distance between the second boundary end P21b of the second boundary line L20b and the second outer peripheral end P42 of the second outer peripheral line L40 is not included in the joint distance W1.
- “100 ⁇ t (%)” is a value obtained by subtracting the ratio t from 100. The larger this value, the smaller the joining area between the outer layer 35 and the metallic shell 50 and the larger the joining area between the second layer 34b and the metallic shell 50.
- the strength evaluation method in Table 2 is the same as the strength evaluation method in Table 1 above. However, the evaluation thresholds are different. That is, A evaluation shows that tensile strength is 550 N / mm 2 or more, B evaluation shows that tensile strength is 450 N / mm 2 or more, and tensile strength is less than 550 N / mm 2 , and C evaluation is , Indicating that the tensile strength is less than 450 N / mm 2 .
- First width of cross section of ground electrode 30b width corresponding to Wa in FIG. 2): 2.0 mm
- Second width of cross section of ground electrode 30b width corresponding to Wb in FIG. 2): 1.6 mm
- Material of outer layer 35 Inconel 601
- Aluminum content of outer layer 35 1.4 wt%
- Material of first layer 34a Pure copper Material of second layer 34b: Pure nickel Surface oxygen content: 5 wt%
- the strength evaluation results tend to be better when the ratio t is smaller than when the ratio t is large.
- the reason is estimated as follows.
- the higher the nickel content (wt%) the stronger the welding strength.
- the smaller the ratio t the larger the bonding area between the second layer 34 b having a higher nickel content than the outer layer 35 and the metal shell 50. Therefore, it is estimated that the welding strength improves as the ratio t decreases.
- the strength evaluation result is not A evaluation but B evaluation. The reason is considered that the first layer 34a may be joined to the metal shell 50 in a cross section different from the reference cross section in which the ratio t is measured.
- achieve A evaluation was 5, 10, 20 (%). Therefore, any value among these values can be adopted as the upper limit of the preferable range of the ratio t. For example, a value of 20% or less can be adopted as the ratio t.
- the ratio t is zero%. It is estimated that the welding strength can be improved as compared with the case of. Therefore, various values larger than zero% can be adopted as the ratio t.
- the above-mentioned preferable range of the ratio t is applicable to various surface oxygen amounts of 5 wt% or less.
- the metal shell 50 is separated from the first layer 34a and is joined to the outer layer 35 and the second layer 34b.
- the metal shell 50 may be joined to all of the outer layer 35, the first layer 34a, and the second layer 34b. Also in this case, it is presumed that the bonding strength can be improved because the bonding area between the second layer 34b and the metal shell 50 can be increased by making the ratio t relatively small. Therefore, it is estimated that the preferable range of the ratio t can be applied also in this case.
- the first boundary lines L10 and L10b include the inclined portions L11 and L11b.
- the two boundary lines between the outer layer 35 and the core portions 36 and 36b in the reference cross section has an inclined portion. According to this configuration, since the joining area between the outer layer 35 and the metal shell 50 can be increased as compared with the case where both of the two boundary lines do not have an inclined portion, the ground electrodes 30, 30b and The joint strength with the metal shell 50 can be improved.
- both of the two boundary lines may include an inclined portion.
- the second boundary lines L20 and L20b include inclined portions extending obliquely from the second boundary ends P21 and P21b toward the outer direction Do.
- the joining distance W1 the first distance between the first boundary ends P11 and P11b and the first outer peripheral end P32 (the joining distance W1 in FIGS. 3 and 5)
- the second boundary ends P21 and P21b A total value of the second distance to the second outer peripheral end P42 is employed.
- the second distance is a distance between the straight lines LP2 and LP2b passing through the second boundary ends P21 and P21b and parallel to the central axis CLx, and the straight line LP4 passing through the second outer peripheral end P42 and parallel to the central axis CLx.
- the first boundary lines L10 and L10b on the inner direction Di side may not include the inclined portion
- the second boundary lines L20 and L20b on the outer direction Do side may include the inclined portion.
- FIG. 6 is a cross-sectional view of an example of a modified spark plug.
- the spark plug 100c of this modification is an example of a spark plug obtained by applying the configuration in which both of the two boundary lines include an inclined portion to the embodiment of FIG.
- FIG. 3 similarly to FIG. 3, a sectional view of a joint portion between the base end portion 30 cx of the ground electrode 30 c and the tip end portion 50 x of the metal shell 50 is shown.
- the difference from the first embodiment shown in FIG. 3 is that the second boundary line L20c on the outer side Do side of the two boundary lines L10 and L20c between the outer layer 35c and the core part 36c of the ground electrode 30c is an inclined portion. It is only a point including L21c.
- the configuration of the portion of the joint portion of the ground electrode 30 c on the inner direction Di side from the central axis CLx is the configuration of the portion of the joint portion of FIG. 3 on the inner direction Di side. And the same.
- the configuration of the portion of the joint portion of the ground electrode 30 c that is on the outer side Do side of the central axis CLx is the same as the configuration of the portion of the inner side Di side of the central axis CLx. This is almost the same as the configuration obtained by performing the mirror conversion with the symmetry axis.
- the configuration of other parts of the ground electrode 30c is substantially the same as the configuration of the ground electrode 30 shown in FIG.
- the configurations of the outer layer 35c and the core portion 36c are substantially the same as the configurations of the outer layer 35 and the core portion 36 in FIG. 3 except for the shape of the second boundary line L20c at the base end portion 30cx.
- the configuration of the spark plug 100c according to the modified example other than the ground electrode 30c is the same as the configuration of the spark plug 100 shown in FIG.
- the same elements as those of the spark plug 100 and the ground electrode 30 of FIGS. 1 and 3 are denoted by the same reference numerals, and description thereof is omitted.
- the inclined portion L11 of the first boundary line L10 is inclined from the first boundary end P11 with respect to the central axis CLx on the outer peripheral side of the portion forming the first boundary line L10 in the outer layer 35c (here, inward direction). Di side).
- the 2nd boundary end P21c in a figure is an end by the side of the metal shell 50 of the 2nd boundary line L20c.
- the inclined portion L21c is inclined from the second boundary end P21c with respect to the central axis CLx of the ground electrode 30c on the outer peripheral side of the portion forming the second boundary line L20c in the outer layer 35c (here, the outer direction Do side) ).
- the outer layer 35c extends along the distal end surface 57 of the metal shell 50 toward the central axis CLx in both the outer direction Do side portion and the inner direction Di side portion of the ground electrode 30c.
- both of the two boundary lines L10 and L20c include the inclined portions L11 and L21c
- the outer layer 35c and the metal shell are compared with the case where only one of the two boundary lines L10 and L20c includes the inclined portion. 50 can be increased. As a result, the bonding strength between the ground electrode 30c and the metal shell 50 can be improved.
- any method can be adopted as a method of forming the joint as shown in FIG.
- first and second cutting blades such as the cutting blade 920 in FIG. 4A are prepared and the ground electrode is sandwiched between the two cutting blades for cutting.
- the first cutting blade moves from the inward direction Di side of the ground electrode toward the central axis CLx
- the second cutting blade moves from the outer direction Do side of the ground electrode toward the central axis CLx.
- the two boundary lines corresponding to L20c are inclined obliquely so as to approach the central axis CLx in the vicinity of the base end face 37c of the ground electrode 30c. Therefore, the inclined portions L11 and L21c in FIG. 6 can be formed by welding similar to that in FIG.
- the surface oxygen amount is preferably within the preferable range of the surface oxygen amount described with reference to Table 1. If such a configuration is adopted, it is estimated that good bonding strength can be realized.
- the surface oxygen amount is preferably 8 wt% or less, and particularly preferably 5 wt% or less.
- the second distance W12 in FIG. 6 is a distance between a straight line LP2c passing through the second boundary end P21c and parallel to the central axis CLx, and a straight line LP4 passing through the second outer peripheral end P42 and parallel to the central axis CLx. It is.
- the joining distance W1 includes a first distance W11 between the first boundary end P11 and the first outer peripheral end P32 (same as the distance W1 in FIG. 3), and a distance between the second boundary end P21c and the second outer peripheral end P42.
- the total value of the second distance W12 is used.
- FIG. 7 is a cross-sectional view of an example of another modified spark plug.
- the spark plug 100d of this modification is an example of a spark plug obtained by applying the configuration in which both of the two boundary lines include an inclined portion to the embodiment of FIG.
- FIG. 5 similarly to FIG. 5, a sectional view of a joint portion between the base end portion 30 dx of the ground electrode 30 d and the tip end portion 50 x of the metal shell 50 is shown.
- the difference from the second embodiment shown in FIG. 5 is that the second boundary line L20d on the outer side Do side of the two boundary lines L10b and L20d between the outer layer 35d and the core part 36d of the ground electrode 30d is an inclined portion. It is only a point including L21d.
- the configuration of the portion of the ground electrode 30d on the inner direction Di side from the central axis CLx is the configuration of the portion of the joint portion of FIG. 5 on the inner direction Di side. And the same. Further, in the modification of FIG. 7, the configuration of the portion of the joint portion of the ground electrode 30d on the outer side Do side with respect to the central axis CLx is the central axis CLx in the configuration of the portion on the inner side Di side with respect to the central axis CLx. This is almost the same as the configuration obtained by performing the mirror conversion with the symmetry axis.
- the configuration of the other part of the ground electrode 30d is substantially the same as the configuration of the ground electrode 30b shown in FIG.
- the configuration of the outer layer 35d and the first layer 34c and the second layer 34d of the core portion 36d is the same as that of the outer layer 35 of FIG. 5 except the shape of the second boundary line L20d at the base end portion 30dx.
- the configuration of the first layer 34a and the second layer 34b of the part 36b is approximately the same.
- the configuration of the spark plug 100d according to the modification other than the ground electrode 30d is the same as the configuration of the spark plug 100 shown in FIG.
- the same elements as those of the spark plug 100 and the ground electrode 30b of FIGS. 1 and 5 are denoted by the same reference numerals, and description thereof is omitted.
- the inclined portion L11b of the first boundary line L10b is inclined from the first boundary end P11b with respect to the central axis CLx on the outer peripheral side of the portion forming the first boundary line L10b in the outer layer 35d (in this case, inward direction) Di side).
- the second boundary end P21d in the drawing is an end of the second boundary line L20d on the metal shell 50 side.
- the inclined portion L21d is inclined from the second boundary end P21d with respect to the central axis CLx of the ground electrode 30d on the outer peripheral side of the portion forming the second boundary line L20d in the outer layer 35d (here, the outer side Do side) ).
- the outer layer 35d extends along the distal end surface 57 of the metal shell 50 toward the central axis CLx in both the outer direction Do side portion and the inner direction Di side portion of the ground electrode 30d.
- both of the two boundary lines L10b and L20d include the inclined portions L11b and L21d
- the outer layer 35d and the metal shell are compared with the case where only one of the two boundary lines L10b and L20d includes the inclined portion. 50 can be increased. As a result, the bonding strength between the ground electrode 30d and the metal shell 50 can be improved.
- any method can be adopted as a method of forming the joint portion as shown in FIG.
- a method using two cutting blades can be adopted as in the method described in the modification of FIG.
- the surface oxygen amount is preferably within the above-described preferable range. If such a configuration is adopted, it is estimated that good bonding strength can be realized.
- the surface oxygen amount is preferably 8 wt% or less, and particularly preferably 5 wt% or less.
- the second distance W12d in FIG. 7 is a distance between a straight line LP2d passing through the second boundary end P21d and parallel to the central axis CLx, and a straight line LP4 passing through the second outer peripheral end P42 and parallel to the central axis CLx. It is.
- the joining distance W1 includes a first distance W11d (same as the distance W1 in FIG.
- a melted part may be formed between the two members.
- the melting part is a part formed by the members to be joined that are melted during welding. Even in such a case, it can be said that two members are joined.
- a melting part may be formed between the ground electrodes 30, 30 b, 30 c, 30 d and the metal shell 50.
- the outer layers 35, 35 c, 35 d and the metal shell 50 are joined via the melting part, it can be said that the outer layers 35, 35 c, 35 d are joined to the metal shell 50.
- the first layers 34a and 34c are separated from the melting part, it can be said that the metal shell 50 is separated from the first layers 34a and 34c.
- the metal shell 50 is joined to the first layers 34a and 34c without being separated from the first layers 34a and 34c. It can be said that.
- the boundary ends include the outer layers 35, 35c, and 35d in the reference cross section and the core portions 36 and 36b. , 36c, and 36d may be adopted at the end of the metal shell 50 side. In this case, the boundary end can be arranged on the outline of the melting part.
- the end on the metal shell 50 side of the outer peripheral line representing the outer peripheral surface of the outer layer 35, 35c, 35d in the reference cross section may be adopted. In this case, the outer peripheral end can be arranged on the outline of the melting part.
- the positions in the direction parallel to the central axis CLx may be different between the four ends of the two boundary ends and the two outer peripheral ends.
- the material of the outer layers 35, 35c, and 35d it is preferable to employ a material containing nickel as a main component and further containing chromium and aluminum. That is, it is preferable to employ a nickel chromium alloy to which at least aluminum is added.
- the aluminum content is not limited to 1.4 wt%, and various values can be employed. For example, a value greater than 0 wt% and not greater than 2.5 wt% can be employed. If a value within such a range is employed, the oxidation resistance of the outer layer 35 can be improved.
- Various values can be adopted as the chromium content. For example, a value in the range of 10 wt% or more and 30 wt% or less can be adopted.
- the material of the second layers 34b and 35d is not limited to pure nickel, and various materials containing more nickel than the outer layers 35 and 35d can be used.
- a nickel alloy such as a nickel chromium alloy can be used.
- the material of the core part 36 in FIG. 3, the first layer 34 a in FIG. 5, the core part 36 c in FIG. 6, and the first layer 34 c in FIG. 7 is not limited to pure copper, but is more thermally conductive than the outer layers 35, 35 c, 35 d.
- Various materials with high rates can be used.
- a material containing copper as a main component can be used.
- a material containing copper as a main component for example, a copper alloy such as a copper nickel alloy can be employed.
- Various values of 100% or less can be adopted as the copper content.
- the copper content is preferably 80 wt% or more, and particularly preferably 95 wt% or more.
- the material of the metal shell 50 is not limited to a low carbon steel material, and various conductive materials that can be welded to the ground electrode 30 can be used. For example, a nickel chromium alloy may be adopted.
- the widths Wa and Wb of the ground electrode 30 are not limited to the above-described sample widths Wa and Wb, and various values can be adopted.
- the configuration of the spark plug is not limited to the configuration described in FIG. 1, and various configurations can be employed.
- a noble metal tip may be provided in a portion of the ground electrodes 30, 30b, 30c, 30d where the gap g is formed.
- materials containing various noble metals such as iridium and platinum can be adopted.
- a noble metal tip may be provided in a portion of the center electrode 20 where the gap g is formed.
- the present disclosure can be suitably used for a spark plug used for an internal combustion engine or the like.
- second seal part 100, 100b, 100c, 100d ... spark plug, 350 ... wide part, 910 ... support, 920 ... cutting blade, L10, L10u, L10b ... first boundary line, L20, L20u, L20b , L20c, L20d ... second boundary line, L30, L30u ... first outer periphery line, L40, L40u ... second outer periphery line, P11, P11b ... first boundary end, P21, P21b, P21c , P21d ... second boundary end, P32 ... first outer peripheral end, P42 ... second outer peripheral end, L11, L11b, L21c, L21d ... inclined portion, CL, CLx ...
Abstract
Description
中心電極と、
前記中心電極を保持する絶縁体と、
前記絶縁体の径方向の周囲に配置される主体金具と、
前記主体金具の先端部に接合された基端部を有するとともに、前記中心電極との間でギャップを形成する接地電極と、
を備えるスパークプラグであって、
前記接地電極は、
前記接地電極の表面の少なくとも一部を形成し、前記主体金具に接合されるとともに、ニッケルを主成分として含みアルミニウムを0wt%より多く2.5wt%以下で含む材料で形成された外層と、
前記外層の内周側に配置される芯部と、
を含み、
前記外層の表面における酸素量は、0wt%を超え、8wt%以下であり、
前記芯部は、銅、または、銅を主成分として含む材料で形成された第1層を含み、
前記スパークプラグの中心軸と前記接地電極の中心軸とを含む断面の前記接地電極の前記基端部において、前記外層と前記芯部との境界を表す2本の境界線のうちの少なくとも一方は、前記境界線の前記主体金具側の端から前記接地電極の前記中心軸に対して斜めに前記外層の外周側に向かって延びる傾斜線を含む、
スパークプラグ。 [Application Example 1]
A center electrode;
An insulator holding the center electrode;
A metal shell disposed around a radial direction of the insulator;
A ground electrode having a proximal end joined to a distal end of the metal shell and forming a gap with the center electrode;
A spark plug comprising:
The ground electrode is
Forming at least a part of the surface of the ground electrode, bonded to the metal shell, and an outer layer formed of a material containing nickel as a main component and aluminum in an amount of more than 0 wt% to 2.5 wt%;
A core portion disposed on the inner peripheral side of the outer layer;
Including
The amount of oxygen on the surface of the outer layer is more than 0 wt% and 8 wt% or less,
The core includes a first layer formed of copper or a material containing copper as a main component,
At the base end portion of the ground electrode having a cross section including the center axis of the spark plug and the center axis of the ground electrode, at least one of two boundary lines representing a boundary between the outer layer and the core portion is An inclined line extending obliquely from the end of the boundary line on the metal shell side toward the outer peripheral side of the outer layer obliquely with respect to the central axis of the ground electrode,
Spark plug.
適用例1に記載のスパークプラグであって、
前記外層の前記表面における前記酸素量は、0wt%を超え、5wt%以下であり、
前記断面の前記接地電極の前記基端部において、
前記傾斜線の前記主体金具側の端を境界端とし、
前記外層の外周面を表す2本の外周線のそれぞれの前記主体金具側の端である2つの外周端の間の前記接地電極の前記中心軸と垂直な方向の距離を全距離W2とし、
前記傾斜線を含む1つまたは2つの前記境界線に関して、前記接地電極の前記中心軸に平行な前記境界端を通る直線と、前記境界端から見て前記傾斜線の延びる方向に位置する前記外周端を通り前記接地電極の前記中心軸に平行な直線と、の間の距離の合計を接合距離W1とし、
前記全距離W2に対する前記接合距離W1の割合を割合tとしたときに、
前記割合tは、0%より大きく、80%以下である、
スパークプラグ。 [Application Example 2]
The spark plug according to application example 1,
The amount of oxygen on the surface of the outer layer is greater than 0 wt% and less than or equal to 5 wt%;
In the base end of the ground electrode of the cross section,
The end on the metal shell side of the inclined line is a boundary end,
The distance in the direction perpendicular to the central axis of the ground electrode between the two outer peripheral ends that are the ends on the metal shell side of each of the two outer peripheral lines representing the outer peripheral surface of the outer layer is defined as a total distance W2.
Regarding one or two of the boundary lines including the inclined line, a straight line passing through the boundary end parallel to the central axis of the ground electrode, and the outer periphery located in a direction in which the inclined line extends when viewed from the boundary end The total distance between the straight line passing through the end and parallel to the central axis of the ground electrode is a junction distance W1,
When the ratio of the joint distance W1 to the total distance W2 is a ratio t,
The ratio t is greater than 0% and not greater than 80%.
Spark plug.
適用例1に記載のスパークプラグであって、
前記芯部は、さらに、一部が前記第1層の内周側に配置されるとともに、前記外層よりも大きな含有率(重量%)でニッケルを含む材料で形成され、前記外層よりも熱伝導率が高い第2層を含み、
前記断面の前記接地電極の前記基端部において、
前記傾斜線の前記主体金具側の端を境界端とし、
前記外層の外周面を表す2本の外周線のそれぞれの前記主体金具側の端である2つの外周端の間の前記接地電極の前記中心軸と垂直な方向の距離を全距離W2とし、
前記傾斜線を含む1つまたは2つの前記境界線に関して、前記接地電極の前記中心軸に平行な前記境界端を通る直線と、前記境界端から見て前記傾斜線の延びる方向に位置する前記外周端を通り前記接地電極の前記中心軸に平行な直線と、の間の距離の合計を接合距離W1とし、
前記全距離W2に対する前記接合距離W1の割合を割合tとしたときに、
前記割合tは、0%より大きく、20%以下である、
スパークプラグ。 [Application Example 3]
The spark plug according to application example 1,
The core portion is further arranged in part on the inner peripheral side of the first layer, and is formed of a material containing nickel with a larger content (% by weight) than the outer layer, and is more thermally conductive than the outer layer. Including a second layer with a high rate,
In the base end of the ground electrode of the cross section,
The end on the metal shell side of the inclined line is a boundary end,
The distance in the direction perpendicular to the central axis of the ground electrode between the two outer peripheral ends that are the ends on the metal shell side of each of the two outer peripheral lines representing the outer peripheral surface of the outer layer is defined as a total distance W2.
Regarding one or two of the boundary lines including the inclined line, a straight line passing through the boundary end parallel to the central axis of the ground electrode, and the outer periphery located in a direction in which the inclined line extends when viewed from the boundary end The total distance between the straight line passing through the end and parallel to the central axis of the ground electrode is a junction distance W1,
When the ratio of the joint distance W1 to the total distance W2 is a ratio t,
The ratio t is greater than 0% and not greater than 20%.
Spark plug.
適用例3に記載のスパークプラグであって、
前記断面において、前記主体金具は、前記第1層から離間しているとともに、前記外層と前記第2層とに接合されている、
スパークプラグ。 [Application Example 4]
The spark plug according to application example 3,
In the cross section, the metal shell is spaced apart from the first layer and joined to the outer layer and the second layer.
Spark plug.
適用例1から4のいずれか1項に記載のスパークプラグであって、
前記外層と前記芯部との前記境界を表す前記2本の境界線の両方が、それぞれ、前記境界線の前記主体金具側の端から前記接地電極の前記中心軸に対して斜めに前記外層のうちの前記境界線を形成する部分の外周側に向かって延びる傾斜線を含む、
スパークプラグ。 [Application Example 5]
The spark plug according to any one of Application Examples 1 to 4,
Both of the two boundary lines representing the boundary between the outer layer and the core portion are respectively inclined with respect to the central axis of the ground electrode from an end of the boundary line on the metal shell side. Including an inclined line extending toward the outer peripheral side of the portion forming the boundary line,
Spark plug.
A-1.スパークプラグの構成:
図1は、第1実施形態のスパークプラグの一例の断面図である。図示されたラインCLは、スパークプラグ100の中心軸を示している。図示された断面は、中心軸CLを含む断面である。以下、中心軸CLのことを「軸線CL」とも呼び、中心軸CLと平行な方向を「軸線方向」とも呼ぶ。中心軸CLを中心とする円の径方向を、単に「径方向」とも呼び、中心軸CLを中心とする円の円周方向を「周方向」とも呼ぶ。中心軸CLと平行な方向のうち、図1における上方向を先端方向D1と呼び、下方向を後端方向D1rとも呼ぶ。先端方向D1は、後述する端子金具40から電極20、30に向かう方向である。また、図1における先端方向D1側をスパークプラグ100の先端側と呼び、図1における後端方向D1r側をスパークプラグ100の後端側と呼ぶ。 A. First embodiment:
A-1. Spark plug configuration:
FIG. 1 is a cross-sectional view of an example of a spark plug according to the first embodiment. The illustrated line CL indicates the central axis of the
評価試験では、第1実施形態の接地電極30と主体金具50とを有する部材のサンプルを用いて、接合強度が評価された。以下の表1は、表面酸素量と、割合tと、強度の評価結果と、の関係を示している。 A-2. Evaluation test:
In the evaluation test, the bonding strength was evaluated using a sample of a member having the
接地電極30の断面の第1幅Wa(図2) :2.8mm
接地電極30の断面の第2幅Wb(図2) :1.5mm
外層35の材料 :インコネル601
外層35のアルミニウムの含有量 :1.4wt%
芯部36の材料 :純銅 Among the 49 types of samples, the configuration other than the surface oxygen amount and the ratio t was common. For example, the following configuration was common to 49 types of samples.
First width Wa (FIG. 2) of the cross section of the ground electrode 30: 2.8 mm
Second width Wb (FIG. 2) of the cross section of the ground electrode 30: 1.5 mm
Material of outer layer 35: Inconel 601
Aluminum content of outer layer 35: 1.4 wt%
Material of core part 36: pure copper
B-1.スパークプラグの構成:
図5は、第2実施形態のスパークプラグの一例の断面図である。図中には、図3と同様に、接地電極30bの基端部30bxと主体金具50の先端部50xとの接合部分の断面図が示されている。図3に示す第1実施形態との差異は、接地電極30bの芯部36bが、第1層34aと、第1層34aの内周側に配置された第2層34bと、を含む点だけである。接地電極30bの構成のうち、芯部36b以外の構成は、図3に示す接地電極30の構成と、同じである。以下、第2実施形態の接地電極30bの要素のうち、図3の接地電極30の要素と同じ要素には、同じ符号を付して、説明を省略する。また、第2実施形態のスパークプラグ100bの構成のうちの接地電極30b以外の構成は、図1に示すスパークプラグ100の構成と、同じである。以下、第2実施形態のスパークプラグ100bの要素のうち、図1のスパークプラグ100の要素と同じ要素には、同じ符号を付して、説明を省略する。 B. Second embodiment:
B-1. Spark plug configuration:
FIG. 5 is a cross-sectional view of an example of the spark plug according to the second embodiment. In the drawing, similarly to FIG. 3, a cross-sectional view of a joint portion between the base end portion 30bx of the
第1実施形態のスパークプラグ100の製造方法と同様の方法を採用可能である。 In addition, as a manufacturing method of the
評価試験では、第2実施形態の接地電極30bと主体金具50とを有する部材のサンプルを用いて、接合強度が評価された。以下の表2は、割合tと、100-tと、強度の評価結果と、の関係を示している。 B-2. Evaluation test:
In the evaluation test, the bonding strength was evaluated using a sample of a member having the
接地電極30bの断面の第1幅(図2のWaに相当する幅):2.0mm
接地電極30bの断面の第2幅(図2のWbに相当する幅):1.6mm
外層35の材料 :インコネル601
外層35のアルミニウムの含有量 :1.4wt%
第1層34aの材料 :純銅
第2層34bの材料 :純ニッケル
表面酸素量 :5wt% It should be noted that the configuration other than the ratio t (ie, 100-t) was common among the eight types of samples. For example, the following configuration is common to eight types of samples.
First width of cross section of
Second width of cross section of
Material of outer layer 35: Inconel 601
Aluminum content of outer layer 35: 1.4 wt%
Material of
(1)上述の実施形態では、第1境界線L10、L10b(図3、図5))が、傾斜部分L11、L11bを含んでいる。一般的には、基準断面における外層35と芯部36、36bとの2本の境界線の少なくとも一方が、傾斜部分を有することが好ましい。この構成によれば、2本の境界線の両方が傾斜部分を有していない場合と比べて、外層35と主体金具50との接合面積を大きくすることができるので、接地電極30、30bと主体金具50との接合強度を向上できる。 C. Variation:
(1) In the above-described embodiment, the first boundary lines L10 and L10b (FIGS. 3 and 5) include the inclined portions L11 and L11b. Generally, it is preferable that at least one of the two boundary lines between the
Claims (5)
- 中心電極と、
前記中心電極を保持する絶縁体と、
前記絶縁体の径方向の周囲に配置される主体金具と、
前記主体金具の先端部に接合された基端部を有するとともに、前記中心電極との間でギャップを形成する接地電極と、
を備えるスパークプラグであって、
前記接地電極は、
前記接地電極の表面の少なくとも一部を形成し、前記主体金具に接合されるとともに、ニッケルを主成分として含みアルミニウムを0wt%より多く2.5wt%以下で含む材料で形成された外層と、
前記外層の内周側に配置される芯部と、
を含み、
前記外層の表面における酸素量は、0wt%を超え、8wt%以下であり、
前記芯部は、銅、または、銅を主成分として含む材料で形成された第1層を含み、
前記スパークプラグの中心軸と前記接地電極の中心軸とを含む断面の前記接地電極の前記基端部において、前記外層と前記芯部との境界を表す2本の境界線のうちの少なくとも一方は、前記境界線の前記主体金具側の端から前記接地電極の前記中心軸に対して斜めに前記外層の外周側に向かって延びる傾斜線を含む、
スパークプラグ。 A center electrode;
An insulator holding the center electrode;
A metal shell disposed around a radial direction of the insulator;
A ground electrode having a proximal end joined to a distal end of the metal shell and forming a gap with the center electrode;
A spark plug comprising:
The ground electrode is
Forming at least a part of the surface of the ground electrode, bonded to the metal shell, and an outer layer formed of a material containing nickel as a main component and aluminum in an amount of more than 0 wt% to 2.5 wt%;
A core portion disposed on the inner peripheral side of the outer layer;
Including
The amount of oxygen on the surface of the outer layer is more than 0 wt% and 8 wt% or less,
The core includes a first layer formed of copper or a material containing copper as a main component,
At the base end portion of the ground electrode having a cross section including the center axis of the spark plug and the center axis of the ground electrode, at least one of two boundary lines representing a boundary between the outer layer and the core portion is An inclined line extending obliquely from the end of the boundary line on the metal shell side toward the outer peripheral side of the outer layer obliquely with respect to the central axis of the ground electrode,
Spark plug. - 請求項1に記載のスパークプラグであって、
前記外層の前記表面における前記酸素量は、0wt%を超え、5wt%以下であり、
前記断面の前記接地電極の前記基端部において、
前記傾斜線の前記主体金具側の端を境界端とし、
前記外層の外周面を表す2本の外周線のそれぞれの前記主体金具側の端である2つの外周端の間の前記接地電極の前記中心軸と垂直な方向の距離を全距離W2とし、
前記傾斜線を含む1つまたは2つの前記境界線に関して、前記接地電極の前記中心軸に平行な前記境界端を通る直線と、前記境界端から見て前記傾斜線の延びる方向に位置する前記外周端を通り前記接地電極の前記中心軸に平行な直線と、の間の距離の合計を接合距離W1とし、
前記全距離W2に対する前記接合距離W1の割合を割合tとしたときに、
前記割合tは、0%より大きく、80%以下である、
スパークプラグ。 The spark plug according to claim 1,
The amount of oxygen on the surface of the outer layer is greater than 0 wt% and less than or equal to 5 wt%;
In the base end of the ground electrode of the cross section,
The end on the metal shell side of the inclined line is a boundary end,
The distance in the direction perpendicular to the central axis of the ground electrode between the two outer peripheral ends that are the ends on the metal shell side of each of the two outer peripheral lines representing the outer peripheral surface of the outer layer is defined as a total distance W2.
Regarding one or two of the boundary lines including the inclined line, a straight line passing through the boundary end parallel to the central axis of the ground electrode, and the outer periphery located in a direction in which the inclined line extends when viewed from the boundary end The total distance between the straight line passing through the end and parallel to the central axis of the ground electrode is a junction distance W1,
When the ratio of the joint distance W1 to the total distance W2 is a ratio t,
The ratio t is greater than 0% and not greater than 80%.
Spark plug. - 請求項1に記載のスパークプラグであって、
前記芯部は、さらに、一部が前記第1層の内周側に配置されるとともに、前記外層よりも大きな含有率(重量%)でニッケルを含む材料で形成され、前記外層よりも熱伝導率が高い第2層を含み、
前記断面の前記接地電極の前記基端部において、
前記傾斜線の前記主体金具側の端を境界端とし、
前記外層の外周面を表す2本の外周線のそれぞれの前記主体金具側の端である2つの外周端の間の前記接地電極の前記中心軸と垂直な方向の距離を全距離W2とし、
前記傾斜線を含む1つまたは2つの前記境界線に関して、前記接地電極の前記中心軸に平行な前記境界端を通る直線と、前記境界端から見て前記傾斜線の延びる方向に位置する前記外周端を通り前記接地電極の前記中心軸に平行な直線と、の間の距離の合計を接合距離W1とし、
前記全距離W2に対する前記接合距離W1の割合を割合tとしたときに、
前記割合tは、0%より大きく、20%以下である、
スパークプラグ。 The spark plug according to claim 1,
The core portion is further arranged in part on the inner peripheral side of the first layer, and is formed of a material containing nickel with a larger content (% by weight) than the outer layer, and is more thermally conductive than the outer layer. Including a second layer with a high rate,
In the base end of the ground electrode of the cross section,
The end on the metal shell side of the inclined line is a boundary end,
The distance in the direction perpendicular to the central axis of the ground electrode between the two outer peripheral ends that are the ends on the metal shell side of each of the two outer peripheral lines representing the outer peripheral surface of the outer layer is defined as a total distance W2.
Regarding one or two of the boundary lines including the inclined line, a straight line passing through the boundary end parallel to the central axis of the ground electrode, and the outer periphery located in a direction in which the inclined line extends when viewed from the boundary end The total distance between the straight line passing through the end and parallel to the central axis of the ground electrode is a junction distance W1,
When the ratio of the joint distance W1 to the total distance W2 is a ratio t,
The ratio t is greater than 0% and not greater than 20%.
Spark plug. - 請求項3に記載のスパークプラグであって、
前記断面において、前記主体金具は、前記第1層から離間しているとともに、前記外層と前記第2層とに接合されている、
スパークプラグ。 The spark plug according to claim 3, wherein
In the cross section, the metal shell is spaced apart from the first layer and joined to the outer layer and the second layer.
Spark plug. - 請求項1から4のいずれか1項に記載のスパークプラグであって、
前記外層と前記芯部との前記境界を表す前記2本の境界線の両方が、それぞれ、前記境界線の前記主体金具側の端から前記接地電極の前記中心軸に対して斜めに前記外層のうちの前記境界線を形成する部分の外周側に向かって延びる傾斜線を含む、
スパークプラグ。 The spark plug according to any one of claims 1 to 4,
Both of the two boundary lines representing the boundary between the outer layer and the core portion are respectively inclined with respect to the central axis of the ground electrode from an end of the boundary line on the metal shell side. Including an inclined line extending toward the outer peripheral side of the portion forming the boundary line,
Spark plug.
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JPH02121289A (en) * | 1988-10-31 | 1990-05-09 | Ngk Spark Plug Co Ltd | Manufacture and welding of outside electrode of spark plug, with good heat-conduction metal wrapped therein |
JP2005353606A (en) * | 2002-02-19 | 2005-12-22 | Denso Corp | Spark plug |
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US6320302B1 (en) | 1999-01-11 | 2001-11-20 | Honeywell International Inc. | Copper core side wire to carbon steel shell weld and method for manufacturing |
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JPH02121289A (en) * | 1988-10-31 | 1990-05-09 | Ngk Spark Plug Co Ltd | Manufacture and welding of outside electrode of spark plug, with good heat-conduction metal wrapped therein |
JP2005353606A (en) * | 2002-02-19 | 2005-12-22 | Denso Corp | Spark plug |
JP2009016278A (en) * | 2007-07-06 | 2009-01-22 | Ngk Spark Plug Co Ltd | Spark plug |
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US20170025822A1 (en) * | 2015-07-22 | 2017-01-26 | Ngk Spark Plug Co., Ltd. | Spark plug |
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