WO2019069640A1 - Bougie d'allumage - Google Patents

Bougie d'allumage Download PDF

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Publication number
WO2019069640A1
WO2019069640A1 PCT/JP2018/033608 JP2018033608W WO2019069640A1 WO 2019069640 A1 WO2019069640 A1 WO 2019069640A1 JP 2018033608 W JP2018033608 W JP 2018033608W WO 2019069640 A1 WO2019069640 A1 WO 2019069640A1
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WIPO (PCT)
Prior art keywords
insulator
ground electrode
distance
electrode
center electrode
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Application number
PCT/JP2018/033608
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English (en)
Japanese (ja)
Inventor
弓野　次郎
かおり 鈴木
今井　奨
悠介 大西
Original Assignee
日本特殊陶業株式会社
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Application filed by 日本特殊陶業株式会社 filed Critical 日本特殊陶業株式会社
Priority to JP2018562269A priority Critical patent/JPWO2019069640A1/ja
Publication of WO2019069640A1 publication Critical patent/WO2019069640A1/fr

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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
    • H01T13/34—Sparking plugs characterised by features of the electrodes or insulation characterised by the mounting of electrodes in insulation, e.g. by embedding

Definitions

  • the present specification relates to a spark plug for igniting fuel gas in an internal combustion engine or the like.
  • a voltage is applied between a ground electrode connected to a metal shell and a center electrode to form a tip of the center electrode and a tip of the ground electrode. Discharge is generated in the gap.
  • Patent Document 1 discloses an ignition plug capable of suppressing the occurrence of side sparks by arranging the inner circumferential surface of the metal shell and the outer circumferential surface of the insulator offset from concentric circles.
  • the present specification discloses a new technology that can suppress the occurrence of the above-described side spark in the spark plug.
  • a cylindrical insulator having an axial hole extending in the axial direction, A center electrode which extends in the axial direction, the rear end side of which is disposed in the shaft hole, and the front end side protrudes to the front end side from the insulator;
  • a metal shell disposed on the outer periphery of the insulator;
  • a ground electrode comprising: a connection end connected to a front end of the metal shell; and a free end opposite to the connection end to form a gap between the connection end and the center electrode;
  • a spark plug comprising The tip of the insulator is located closer to the tip than the tip of the metal shell, In a cross section perpendicular to the axis and including the ground electrode and the insulator, A circumferential position at which the distance between the outer peripheral surface of the center electrode and the inner peripheral surface of the insulator is maximized is a first position.
  • the circumferential position which is a circumferential position different from the first position, and in which the distance between the outer circumferential surface of the center electrode and the inner circumferential surface of the insulator is a minimum, is a second position.
  • the first position is located within the ground electrode range
  • the second position is located outside the ground electrode range
  • a spark plug wherein a shortest distance between an inner circumferential surface of the ground electrode and an outer circumferential surface of the insulator is 1 mm or less.
  • the first position at which the distance between the center electrode and the insulator is maximized is located within the ground electrode range, and the distance between the center electrode and the insulator is minimized. Position is outside the ground electrode range. As a result, even if the distance between the ground electrode and the insulator is 1 mm or less in the above cross section, the occurrence of side spark can be suppressed.
  • the spark plug according to Application Example 1 is, A spark plug, wherein a distance in an axial direction between a tip of the insulator and a tip of the metal shell is 0.5 mm or more.
  • the tip of the metal shell has a high local electric field strength, side sparks are likely to occur between the tip of the metal shell and the center electrode. According to the above configuration, the creeping path of the insulator between the end of the metal shell and the center electrode can be made sufficiently long, so the occurrence of side sparks can be further suppressed.
  • the first distance at the first position is three or more times larger than the second distance at the second position. It can be made long enough. As a result, the occurrence of side sparks can be further suppressed.
  • an ignition device using an ignition plug or an ignition plug an internal combustion engine equipped with the ignition plug, or the ignition plug
  • the present invention can be realized in the form of an internal combustion engine equipped with an ignition device using the above, an electrode of a spark plug, and the like.
  • FIG. 5 is an enlarged cross-sectional view of the vicinity of the tip of the spark plug 100. It is a figure which shows the cross section AA of 1st Embodiment. It is a graph which shows the evaluation result of a 1st evaluation test. It is a graph which shows the evaluation result of a 2nd evaluation test. It is an expanded sectional view near the tip of a spark plug of a 2nd embodiment. It is a figure which shows the cross section AA of the ignition plug of 3rd Embodiment.
  • FIG. 1 is a cross-sectional view of the spark plug 100 of the present embodiment.
  • FIG. 2 is an enlarged cross-sectional view of the vicinity of the tip of the spark plug 100.
  • 1 and 2 indicate the axis AXa of the spark plug 100.
  • the direction parallel to the axis AXa (vertical direction in FIGS. 1 and 2) is also referred to as an axial direction.
  • the radial direction of a circle on a plane perpendicular to the axis AXa with the axis AXa as the center is also simply referred to as "radial direction", and the circumferential direction of the circle is also simply referred to as "circumferential direction".
  • FIGS. 1 and 2 are referred to as a front end direction FD, and the upward direction is also referred to as a back end direction BD.
  • the lower side in FIGS. 1 and 2 is referred to as the tip end side of the spark plug 100, and the upper side in FIGS. 1 and 2 is referred to as the rear end side of the spark plug 100.
  • the spark plug 100 is attached to an internal combustion engine and is used to ignite combustion gases in a combustion chamber of the internal combustion engine.
  • the spark plug 100 includes an insulator 10, a center electrode 20, a ground electrode 30, a terminal electrode 40, a metal shell 50, a resistor 70, and conductive seal members 60 and 80.
  • the insulator 10 is a substantially cylindrical member having an axial hole 12 which is a through hole extending in the axial direction and penetrating the insulator 10.
  • the insulator 10 is formed using, for example, a ceramic such as alumina.
  • the insulator 10 includes a collar portion 19, a rear end side body portion 18, a front end side body portion 17, a reduced outer diameter portion 15, and a leg length portion 13.
  • the flange portion 19 is a portion of the insulator 10 located substantially at the center in the axial direction.
  • the rear end side body portion 18 is located on the rear end side of the collar portion 19 and has an outer diameter smaller than the outer diameter of the collar portion 19.
  • the front end side body portion 17 is located on the front end side with respect to the collar portion 19 and has an outer diameter smaller than the outer diameter of the rear end side body portion 18.
  • the long leg portion 13 is located on the tip end side of the tip end side body portion 17 and has an outer diameter smaller than the outer diameter of the tip end side body portion 17.
  • the outer diameter of the leg portion 13 is reduced toward the tip end, and is exposed to the combustion chamber when the spark plug 100 is attached to an internal combustion engine (not shown).
  • the reduced outer diameter portion 15 is a portion which is formed between the leg length portion 13 and the front end side body portion 17 and whose outer diameter is reduced from the rear end side toward the front end side.
  • the insulator 10 is located on the tip end side of the large inner diameter portion 12L located on the rear end side and the large inner diameter portion 12L, and the inner diameter is smaller than the large inner diameter portion 12L.
  • An inner diameter portion 12S and a reduced diameter inner diameter portion 16 are provided.
  • the reduced diameter portion 16 is formed between the large inner diameter portion 12L and the small inner diameter portion 12S, and is a portion whose inner diameter is reduced from the rear end side toward the front end side.
  • the position in the axial direction of the reduced diameter portion 16 is the position of the tip end side portion of the tip end side body portion 17 in the present embodiment.
  • the metal shell 50 is a cylindrical metal fitting for fixing the spark plug 100 to an engine head (not shown) of an internal combustion engine, which is formed of a conductive metal material (for example, low carbon steel material).
  • the metal shell 50 is formed with a through hole 59 penetrating along the axis AXa.
  • the metal shell 50 is disposed around the radial direction (that is, the outer periphery) of the insulator 10. That is, the insulator 10 is inserted and held in the through hole 59 of the metal shell 50.
  • the tip of the insulator 10 protrudes from the tip of the metal shell 50 toward the tip.
  • the rear end of the insulator 10 protrudes from the rear end of the metal shell 50 toward the rear end.
  • the metal shell 50 is formed between a tool engagement portion 51 in the form of a hexagonal column engaged with the spark plug wrench, a mounting screw portion 52 for mounting on an internal combustion engine, and the tool engagement portion 51 and the mounting screw portion 52. And a hooked seat portion 54.
  • the nominal diameter of the mounting screw portion 52 is, for example, M8 to M14.
  • a metal annular gasket 5 is inserted between the mounting screw 52 and the seat 54 of the metal shell 50.
  • the gasket 5 seals a gap between the spark plug 100 and the internal combustion engine (engine head) when the spark plug 100 is attached to the internal combustion engine.
  • the metal shell 50 further includes a thin caulking portion 53 provided on the rear end side of the tool engagement portion 51, and a thin compression deformation portion 58 provided between the seat portion 54 and the tool engagement portion 51. And have.
  • Annular wire packings 6, 7 are arranged in an annular region formed between the inner peripheral surface of a portion from the tool engagement portion 51 to the caulking portion 53 in the metal shell 50 and the outer peripheral surface of the rear end side body portion 18 of the insulator 10.
  • Annular wire packings 6, 7 are arranged in an annular region formed between the inner peripheral surface of a portion from the tool engagement portion 51 to the caulking portion 53 in the metal shell 50 and the outer peripheral surface of the rear end side body portion 18 of the insulator 10.
  • a powder of talc (talc) 9 is filled between the two line packings 6 and 7 in the area concerned.
  • the rear end of the crimped portion 53 is bent inward in the radial direction and fixed to the outer peripheral surface of the insulator 10.
  • the compression deformation portion 58 of the metal shell 50 is compressed and deformed when the crimped portion 53 fixed to the outer peripheral surface of the insulator 10 is pressed toward the tip end during manufacturing.
  • the insulator 10 is pressed toward the tip side in the metal shell 50 through the wire packings 6, 7 and the talc 9.
  • a reduced diameter portion 15 (insulator side step) of the insulator 10 by a step portion 56 (a fitting side step portion) formed on the inner periphery of the metal shell 50 at the mounting screw portion 52 via the annular plate packing 8 Section) is pressed.
  • the plate packing 8 prevents the gas in the combustion chamber of the internal combustion engine from leaking from the gap between the metal shell 50 and the insulator 10 to the outside.
  • the center electrode 20 includes a rod-shaped center electrode body 21 extending along the axial direction, and a center electrode tip 29.
  • the center electrode body 21 is held at a tip end side portion inside the axial hole 12 of the insulator 10. That is, the rear end side (the rear end side of the center electrode body 21) of the center electrode 20 is disposed in the shaft hole 12.
  • the center electrode body 21 is formed using a metal having high corrosion resistance and heat resistance, such as nickel (Ni) or an alloy containing Ni as a main component (for example, NCF 600, NCF 601).
  • the center electrode body 21 may have a two-layer structure including a base material formed of Ni or a Ni alloy, and a core portion embedded inside the base material.
  • the core is made of, for example, copper or an alloy containing copper as a main component, which is more excellent in thermal conductivity than the base material.
  • the center electrode body 21 includes a collar 24 provided at a predetermined position in the axial direction, and a head 23 (electrode head) which is a portion on the rear end side of the collar 24. And a leg portion 25 (electrode leg portion) which is a portion on the tip end side of the heel portion 24.
  • the flange portion 24 is supported from the distal end side by the reduced diameter portion 16 of the insulator 10. That is, the center electrode body 21 is locked to the reduced diameter portion 16.
  • the tip end side of the leg portion 25, that is, the tip end of the center electrode body 21 protrudes from the tip end 10 A of the insulator 10 toward the tip end side.
  • the center electrode tip 29 is, for example, a member having a substantially cylindrical shape, and is joined to the end of the center electrode body 21 (the end of the leg 25) using, for example, laser welding.
  • the front end surface of the center electrode tip 29 is a first discharge surface 295 that forms a spark gap with the ground electrode tip 39 described later.
  • the center electrode tip 29 is formed using, for example, a high melting point noble metal such as iridium (Ir) or platinum (Pt), or an alloy containing the noble metal as a main component.
  • the terminal electrode 40 is a rod-like member extending in the axial direction.
  • the terminal electrode 40 is inserted into the axial hole 12 of the insulator 10 from the rear end side, and is located on the rear end side of the center electrode 20 in the axial hole 12.
  • the terminal electrode 40 is formed of a conductive metal material (for example, low carbon steel), and on the surface of the terminal electrode 40, for example, a plating such as Ni is formed for corrosion protection.
  • the terminal electrode 40 has a hook 42 (terminal jaw) formed at a predetermined position in the axial direction, a cap mounting part 41 positioned on the rear end side of the hook 42, and a leg 43 on the tip side of the hook 42. And (terminal legs).
  • the cap mounting portion 41 of the terminal electrode 40 is exposed to the rear end side of the insulator 10.
  • the leg 43 of the terminal electrode 40 is inserted into the axial hole 12 of the insulator 10.
  • a plug cap to which a high voltage cable (not shown) is connected is mounted on the cap mounting portion 41, and a high voltage for generating a discharge is applied.
  • the resistor 70 is disposed in the axial hole 12 of the insulator 10 between the front end of the terminal electrode 40 and the rear end of the center electrode 20.
  • the resistor 70 has, for example, a resistance value (for example, 5 K ⁇ ) of 1 K ⁇ or more, and has a function of reducing radio wave noise at the time of spark generation.
  • the resistor 70 is formed of, for example, a composition including glass particles as main components, ceramic particles other than glass, and a conductive material.
  • the gap between the resistor 70 and the center electrode 20 in the shaft hole 12 is filled with the conductive seal member 60.
  • the gap between the resistor 70 and the terminal electrode 40 is filled with the seal member 80. That is, the seal member 60 is in contact with the center electrode 20 and the resistor 70 respectively, and the center electrode 20 and the resistor 70 are separated.
  • the seal member 80 is in contact with the resistor 70 and the terminal electrode 40, and separates the resistor 70 and the terminal electrode 40 from each other.
  • the seal members 60 and 80 electrically and physically connect the center electrode 20 and the terminal electrode 40 via the resistor 70.
  • the seal members 60 and 80 are formed of a conductive material, for example, a composition containing glass particles such as B 2 O 3 —SiO 2 and metal particles (Cu, Fe, etc.).
  • the ground electrode 30 (ground electrode main body 31) is a rod-like body having a square cross section as shown in FIG.
  • the ground electrode body 31 has a connection end 312 and a free end 311 opposite to the connection end 312 as both ends.
  • the connection end 312 is joined to the end 50A of the metal shell 50 by, for example, resistance welding.
  • the metal shell 50 and the ground electrode body 31 are electrically and physically connected.
  • the vicinity of the connection end 312 of the ground electrode body 31 extends in the direction of the axis AXa, and the vicinity of the free end 311 extends in the direction perpendicular to the axis AXa.
  • the rod-like ground electrode body 31 is curved by about 90 degrees in the central portion.
  • the ground electrode body 31 is formed using a metal having high corrosion resistance and heat resistance, Ni, or an alloy mainly composed of Ni (for example, NCF 600, NCF 601).
  • the ground electrode main body 31 includes a base material and a core portion formed of a metal (for example, copper) having a higher thermal conductivity than the base material and embedded in the base material, as the center electrode main body 21. It may have a two-layer structure.
  • a ground electrode tip 39 having a second discharge surface 395 opposed to the first discharge surface 295 of the center electrode 20 with a gap G formed therebetween is joined.
  • the ground electrode tip 39 has, for example, a cylindrical shape or a square pole shape.
  • a gap G between the first discharge surface 295 and the second discharge surface 395 is a so-called spark gap in which a discharge occurs.
  • the ground electrode tip 39 is formed using, for example, a noble metal or an alloy containing a noble metal as a main component, similarly to the center electrode tip 29.
  • the tip end 10A of the insulator 10 (the tip end of the leg length 13) is located on the tip end side of the tip end 50A of the metal shell 50.
  • the distance in the axial direction between the front end 10A of the insulator 10 and the front end 50A of the metal shell 50 is taken as a protrusion amount H.
  • FIG. 3 is a view showing a cross section AA perpendicular to the axis AXa, passing through a portion of the insulator 10 on the tip end side of the tip end 50A of the metal shell 50. As shown in FIG. In FIG. 2, the cross section AA is indicated by a broken line.
  • the cross section AA includes the ground electrode 30 (connection end 312), the center electrode 20 (legs 25), and the insulator 10 (legs 13).
  • the metal shell 50 is not included in the cross section AA.
  • the broken line in FIG. 3 indicates the position of the metal shell 50 as viewed from the tip end along the axis AXa.
  • the shortest distance between the inner circumferential surface 30i of the ground electrode 30 and the outer circumferential surface 10o of the insulator 10 is C3. Since the spark plug 100 is a relatively small diameter spark plug, the shortest distance C3 is 1.2 mm or less.
  • the axis (central axis) of the insulator 10 (leg length 13) and the axis of the metal shell 50 are the axis AXa of the spark plug 100.
  • the axes of the head portion 23 and the collar portion 24 of the center electrode main body 21 are similarly the axes AXa of the spark plug 100.
  • the axis of the leg 25 of the center electrode body 21 and the axis of the center electrode tip 29, that is, the axis on the tip end side of the ridge 24 of the center electrode 20 is an axis AXb different from the axis AXa.
  • the axis of the ground electrode tip 39 of the ground electrode 30 is also an axis AXb different from the axis AXa.
  • a direction (rightward direction in FIG. 3) from the center 30C of the ground electrode 30 (connection end 312) toward the axis AXa of the spark plug 100 is taken as a first direction D1.
  • a direction (upper direction in FIG. 3) perpendicular to the first direction D1 is taken as a second direction D2.
  • the axis AXb is in the first direction D1 when viewed from the axis AXa. That is, in the cross section AA, the axis AXb of the center electrode 20 (leg portion 25) is offset in the first direction D1 with respect to the axis AXa of the metallic shell 50 and the insulator 10.
  • the distance between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 differs depending on the position in the circumferential direction viewed from the axis AXb of the center electrode 20.
  • the circumferential position at which the distance C between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 is maximized is taken as a first position P1.
  • a circumferential position at which the distance C between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 is minimum is taken as a second position P2.
  • the first position P1 and the second position P2 are different. Then, the distance between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 at the first position P1 is taken as a first distance C1 (also referred to as the maximum clearance C1). The distance between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 in the above is the second distance C2 (also referred to as the minimum clearance C2).
  • tangents L1 and L2 are taken as tangents L1 and L2. It is a range in the circumferential direction sandwiched by two tangent lines, and a range in which the ground electrode 30 is positioned is taken as a ground electrode range ER.
  • the first position P1 is located within the ground electrode range ER. Specifically, the first position is a position in a direction opposite to the first direction D1 when viewed from the axis AXb.
  • the second position P2 is located outside the ground electrode range ER. Specifically, the second position P2 is a position directed in the first direction D1 when viewed from the axis AXb.
  • Position P ( ⁇ ) in the circumferential direction in cross section AA is a line segment connecting axis AXb and position P ( ⁇ ) in cross section AA, and a line segment connecting axis AX b and reference position P (0) It is expressed by an angle ⁇ between them.
  • position P1 of maximum clearance C1 is at position P (180) and position P2 of minimum clearance C2 is at position P (0).
  • the ground electrode range ER is a range of an angle (2 ⁇ ⁇ ) centered on the position P (180), that is, a range from the position P (180 ⁇ ) to the position P (180 + ⁇ ). ⁇ is, for example, about 10 degrees.
  • the position P (180) is a position in the circumferential direction from the axis line AXb of the center electrode 20 toward the center 30C of the ground electrode 30 in the cross section AA.
  • the shortest distance C3 is 1.2 mm or less
  • so-called side spark easily occurs as compared with the case where the shortest distance C3 is larger than 1.2 mm.
  • the side spark is a defect that discharge occurs between the center electrode 20 and the connection end 312 of the ground electrode 30 or the tip 50A of the metal shell 50 via the surface of the insulator 10.
  • the shortest distance C3 is 1.2 mm or less, but the first position P1 described above is located within the ground electrode range ER in the cross section AA of FIG.
  • the position P2 is located outside the ground electrode range ER.
  • the side spray is on a path from the center electrode 20 to a direction in the ground electrode range ER (for example, in the opposite direction to the first direction D1 in FIG. 2 and FIG. 3) like a side spray passing the path FT shown in FIG. It is easy to occur in Of the entire circumference of the front end 10A of the metal shell 50, the portion to which the connection end 312 of the ground electrode 30 is connected is particularly high in electric field strength. In other words, in the cross section AA, the side spark has different easiness to occur depending on the position in the circumferential direction viewed from the axis line AXb of the center electrode 20. Specifically, at a position within the ground electrode range ER, side sparks are more likely to occur than a position outside the ground electrode range ER.
  • the insulator 10 in the ground electrode range ER is The distance between the inner peripheral surface 10i and the outer peripheral surface 20o of the center electrode 20 can be longer than the distance between the inner peripheral surface 10i of the insulator 10 and the outer peripheral surface 20o of the center electrode 20 outside the ground electrode range ER. .
  • the insulation resistance between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 in the ground electrode range ER is set to the inner circumferential surface 10i of the insulator 10 outside the ground electrode range ER and the center electrode 20 It can be larger than the insulation resistance between the outer peripheral surface 20 o of As a result, the occurrence of side spark can be suppressed at a position within the ground electrode range ER where side spark easily occurs. Therefore, even if the shortest distance C3 is 1.2 mm or less, the occurrence of side sparks can be suppressed.
  • the distance between the tip end 10A of the insulator 10 and the tip end 50A of the metal shell 50 in the axial direction that is, the protrusion amount H in FIG. Is preferred.
  • the electric field strength is locally high.
  • side spark easily occurs between the tip 10 A of the metal shell 50 and the center electrode 20.
  • the creeping path ST is a path along the surface (for example, the outer peripheral surface 10 o) of the insulator 10 and is, for example, a portion indicated by a broken line in the path FT of FIG. 2.
  • the shortest distance C3 between the inner circumferential surface 30i of the ground electrode 30 and the outer circumferential surface 10o of the insulator 10 in the cross section AA of FIG. 3 is preferably 1 mm or less.
  • the shortest distance C3 is 1 mm or less at the cross section AA, in particular, side spark easily occurs. According to the above configuration, in the cross section AA, even if the shortest distance C3 is 1 mm or less, the occurrence of side spark can be suppressed.
  • the distance C1 between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 at the first position P1 is a first distance C1.
  • the distance C2 between the inner circumferential surface 10i of the insulator 10 and the outer circumferential surface 20o of the center electrode 20 at the second position P2 is a second distance C2
  • the first distance C1 is the second distance It is preferable that it is 3 times or more of C2. According to the above configuration, it is possible to sufficiently lengthen the path (e.g., the path FT in FIG. 2) of energization when a side spark occurs in the ground electrode range ER. As a result, the occurrence of side sparks can be further suppressed.
  • A-2 First Evaluation Test
  • 12 types of samples SA having a shortest distance C3 of 1 mm in FIG. 3 and 12 types of samples SB having a shortest distance C3 of 1.2 mm for the ignition plug A total of 36 types of samples were created, with 12 types of samples SC having a shortest distance C3 of 1.4 mm.
  • the shortest distance C3 is adjusted to one of 1.0 mm, 1.2 mm, and 1.4 mm by changing the inner diameter in the vicinity of the end 50A of the metal shell 50.
  • the cross section AA of each sample was measured at a position 1.0 mm away from the end 50A of the metal shell 50 on the end side.
  • 12 types of samples SA have a circumferential position P1 (first position P1) at which the maximum clearance C1 is located and a circumferential position P2 (second position) at which the minimum clearance C2 is located. It is different.
  • the configurations other than the first position P1 and the second position P2 are the same in each sample.
  • the first position P1 and the second position P2 of the 12 types of samples SA are shifted by 30 degrees.
  • the angles ⁇ indicating the first positions P1 of the 12 types of samples SA are 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, respectively.
  • the samples SA, SB, and SC are also expressed as samples SA ( ⁇ ), SB ( ⁇ ), and SC ( ⁇ ) using the angle ⁇ indicating the first position P1 of the 12 types of samples SA.
  • the second position P2 is on the opposite side of the first position P1 across the axis AXb.
  • samples SA (180), SB (180), SC (180) are the spark plug 100 of the embodiment of FIG. 3, the first position P1 is the position P (180) and the second position P2 is the position P (0).
  • the first position P1 is located within the ground electrode range ER, and the second position P2 is located outside the ground electrode range ER.
  • the first position P1 is located outside the ground electrode range ER, and the second position P2 is grounded. It is located within the electrode range ER.
  • the first position P1 and the second position P1 are both located outside the ground electrode range ER.
  • FIG. 4 is a graph showing the evaluation results of the first evaluation test.
  • the circumferential position in the graph of FIG. 4 indicates the first position P1 of each sample (the circumferential position at which the maximum clearance C1 is located).
  • the rate of side sparks is plotted on the radial axis of the graph.
  • the side spark occurrence rate of the sample SA (180) at the first position P1 at the position P (180) of the ground electrode 30 is the lowest, 4%. Then, the side spark incidence rate of the samples SA (150) and SA (210) whose first position P1 is 30 degrees away from the position P (180) of the ground electrode 30 is as low as that of the sample SA (180) , 5%. In addition, in the samples SA (120) and SA (240) where the first position P1 is 60 degrees away from the position P (180) of the ground electrode 30, the side spark is slightly generated compared to the sample SA (180) The rate was high, 10%.
  • the sample SA in which the first position P1 is 90 degrees or more from the position P (180) of the ground electrode 30 is compared with the samples SA (120) and SA (240) 60 degrees from the position P (180).
  • the rate of side sparks increased significantly.
  • the side spark incidence rate of samples SA (270) and SA (90) was 30% and 25%
  • the side spark incidence rate of samples SA (300) and SA (60) was 36%.
  • the side spark occurrence rate further increases significantly.
  • the side spark incidence rate of samples SA (330) and SA (30) was 60%.
  • the side spark occurrence rate is maximum, which is 72%.
  • the side spark incidence rate of the sample SB (180) at the first position P1 at the position P (180) of the ground electrode 30 is the lowest and 4%.
  • the side spark incidence rate of the samples SB (150) and SB (210) whose first position P1 is 30 degrees away from the position P (180) of the ground electrode 30 is as low as the sample SB (180). , 5%.
  • the side spark is slightly generated compared to the sample SB (180). The rate was high, 10%.
  • the sample SB in which the first position P1 is 90 degrees or more away from the position P (180) of the ground electrode 30 is compared with the samples SB (120) and SB (240) 60 degrees away from the position P (180).
  • the rate of side sparks increased significantly.
  • the side spark incidence rate of samples SB (270) and SB (90) was 25%
  • the side spark incidence rate of samples SB (300) and SB (60) was 30%.
  • the side spark occurrence rate further increases significantly.
  • the side spark incidence rate of samples SB (330) and SB (30) was 50%.
  • the side spark occurrence rate is maximum, which is 60%.
  • the side spark incidence rate of the sample SC (180) at the first position P1 at the position P (180) of the ground electrode 30 is the lowest and 4% . Then, the side spark incidence rate of the samples SC (150) and SC (210) whose first position P1 is 30 degrees away from the position P (180) of the ground electrode 30 is as low as the sample SC (180). , 5%. In addition, in the samples SC (120) and SC (240) in which the first position P1 is 60 degrees away from the position P (180) of the ground electrode 30, the side spark is slightly generated compared to the sample SC (180). The rate was high, 10%.
  • the side spark generation rate was similar to that of the samples SC (120) and SC (240). That is, the side spark incidence rate of samples SC (90), SC (60), SC (30), SC (0), SC (270), SC (300), and SC (330) is 10% to 12%. there were.
  • the occurrence of side spark can be suppressed significantly.
  • the shortest distance C3 was 1.0 mm, it was confirmed that the effect of suppressing the generation of side sparks was high.
  • the first distance C1 (0.15 mm) of each sample is set to three times the second distance C2 (0.05 mm).
  • the path e.g., the path FT in FIG.
  • A-3 Second Evaluation Test
  • the projecting amounts H of the nine types of samples are ⁇ 0.2 mm, 0 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, respectively.
  • the configurations other than the protrusion amount H of these samples are the same as the sample SB (180) used in the first evaluation test.
  • the protrusion amount H of negative value means that the front end 10A of the insulator 10 is positioned on the rear end side relative to the front end 50A of the metal shell 50.
  • FIG. 5 is a graph showing the evaluation results of the second evaluation test.
  • the evaluation result is plotted with the horizontal axis as the protrusion amount H and the vertical axis as the horizontal axis generation rate.
  • the rate of occurrence of side sparks in the samples having a protrusion amount H of 0.5 mm or more was 20% or less. That is, the side spark incidence rates of the samples having the protrusion amount H of 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm and 5 mm are 5%, 4%, 4%, 10%, 15% and 20%, respectively. there were.
  • the side spark incidence rate of the sample whose protrusion amount H is smaller than 0.5 mm was 40% or more.
  • the side spark incidence rates of the samples having the protrusion amount H of ⁇ 0.2 mm, 0 mm and 0.2 mm were 40%, 55% and 40%. According to the second evaluation test, it was confirmed that the occurrence of side spray can be further suppressed when the protrusion amount H in FIG. 2 is 0.5 mm or more.
  • FIG. 6 is an enlarged cross-sectional view of the vicinity of a tip end of a spark plug according to a second embodiment.
  • the spark plug according to the second embodiment includes a center electrode 20B different from the center electrode 20 (FIG. 2) of the spark plug 100 according to the first embodiment.
  • the configuration of the portion of the spark plug of the second embodiment excluding the center electrode 20B is the same as the configuration of the spark plug 100 of the first embodiment.
  • the configuration of the head portion 23 and the heel portion 24 is the same as that of the center electrode 20 of the first embodiment.
  • the configuration of the leg 25B is different from that of the center electrode 20 of the first embodiment.
  • the leg 25B of the center electrode 20B includes a first leg 26B on the rear end side and a second leg 27B on the front end side.
  • the axis of the first leg 26B is the axis AXa of the spark plug, as is the axis of the head 23 and the collar 24.
  • the axis of the second leg 27B is an axis AXb different from the axis AXa.
  • the axis AXb is also an axis of the ground electrode tip 39 of the ground electrode 30. Similar to the first embodiment, the axis AXb of the second leg 27B is offset in the first direction D1 with respect to the axis AXa of the metal shell 50 and the insulator 10.
  • the position (first position P1) of the maximum clearance C1 is located on the opposite side to the first direction D1 when viewed from the axis AXb of the center electrode 20B. ing. That is, the first position P1 is located on the side where the ground electrode 30 is located (within the ground electrode range ER).
  • the position (second position P2) of the minimum clearance C2 is located in the first direction D1 when viewed from the axis AXb of the center electrode 20B. That is, the second position P2 is located outside the ground electrode range ER.
  • FIG. 7 is a view showing a cross section AA of a spark plug according to a third embodiment.
  • the spark plug of the third embodiment includes a center electrode 20C different from the center electrode 20 (FIG. 2) of the spark plug 100 of the first embodiment.
  • the configuration of the portion excluding the center electrode 20C in the spark plug of the third embodiment is the same as the configuration of the spark plug 100 of the first embodiment.
  • the cross section AA of FIG. 7 passes through the portion of the insulator 10 closer to the tip end than the tip 50A of the metal shell 50, and Vertical cross section is shown.
  • the center electrode 20C includes a leg 25C different from the leg 25 of the center electrode 20 of the first embodiment.
  • the other configuration of the center electrode 20C is the same as that of the center electrode 20 of the first embodiment.
  • the cross section of the leg 25C in the direction perpendicular to the axis AXa is not a circle.
  • the outer circumferential surface 20Co of the leg 25C includes an arc-shaped first portion 21o and a straight second portion 22o.
  • the second portion 22o is located on the side of the ground electrode 30 as viewed from the axis AXa
  • the first portion 21o is located on the opposite side to the ground electrode 30 (the first direction D1 side) as viewed from the axis AXa. ing.
  • the distance from the axis AXa to a point on the second portion 22o is shorter than the distance from the axis AXa to a point on the first portion 21o.
  • the position of the maximum clearance C1 (first position P1) is located on the side where the second portion 22o is located. That is, the first position P1 is located on the side where the ground electrode 30 is located (within the ground electrode range ER).
  • the position (second position P2) of the minimum clearance C2 is located on the opposite side (outside of the ground electrode range ER) to the ground electrode 30.
  • the minimum clearance C2 may be zero. That is, for example, in the first embodiment, the leg portion 25 may be in contact with the inner circumferential surface 10i of the insulator 10 (the leg portion 13) at the second position P2 (P (0)).
  • the center electrodes 20, 20B, and 20C in each of the above embodiments may or may not include a tip.
  • the ground electrode 30 may or may not include a tip.
  • the position of the maximum clearance C1 and the position of the minimum clearance C2 by shifting the axis AXb of the leg 25 of the center electrode 20 with respect to the axis AXa of the spark plug 100; Form.
  • the thickness of the insulator 10 thinner at the position on the side of the ground electrode 30 than at the side opposite to the ground electrode 30, the position of the maximum clearance C1 and the position of the minimum clearance C2 , May be formed.
  • the configuration of the center electrodes 20, 20B, and 20C has been mainly described, but other elements, for example, materials and dimensions of the metal shell 50, the terminal electrode 40, the ground electrode 30, etc. , Can be changed in various ways.
  • the material of the metal shell 50 may be a low carbon steel plated with zinc, nickel or the like, or a low carbon steel not plated with these metals.
  • the ground electrode 30 may form a spark gap in the direction perpendicular to the axial direction, facing the tip portion of the center electrode in the direction perpendicular to the axial direction.
  • the present invention can be suitably used for a spark plug.
  • Body 18 Rear end body 19: collar 19 20, 20B, 20C: center electrode 20B: central electrode 21: central electrode body 23: head 24: collar 24: 25 leg , 25B: leg portion 25C: leg portion 26B: first leg portion 27B: second leg portion 29: central electrode tip 30: ground electrode 31: ground electrode main body 39: ground electrode tip 40: Terminal electrode 41 Cap mounting portion 42 Collar portion 43 Leg portion 50 Main body fitting 51 Tool engagement portion 52 Mounting screw portion 53 Crimping portion 54 Seat portion 56 Stepped part, 58: compression deformation part, 59: through hole, 60: sealing member, 70: resistor, 80: sealing member, 00 ...
  • spark plug 311 ... free end, 312 ... connection end, G ... gap, H ... protrusion amount, C ... distance, P1 ... first position, C1 ... maximum clearance, P2 ... second position, C2 ... minimum clearance, C3 ... shortest distance, AA ... cross section, ER ... ground electrode range, AXa ... axis, AXb ... axis

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  • Spark Plugs (AREA)

Abstract

La présente invention concerne une bougie d'allumage qui comprend : un isolant cylindrique ; une électrode centrale, dont le côté d'extrémité arrière est disposé à l'intérieur d'un trou d'arbre, et dont le côté d'extrémité de pointe fait saillie plus vers le côté d'extrémité de pointe que l'isolant ; un raccord métallique de corps principal disposé sur la périphérie externe de l'isolant ; et une électrode de masse comprenant une extrémité de liaison qui est reliée à une pointe du raccord métallique de corps principal, et une extrémité libre qui forme un espace avec l'électrode centrale et fait face à l'espace. Dans une section transversale perpendiculaire à l'axe et comprenant l'électrode de masse et l'isolant, lors de la définition de la position dans la direction circonférentielle où la distance entre la surface périphérique externe de l'électrode centrale et la surface périphérique interne de l'isolant est plus grande comme la première position, et la position dans la direction circonférentielle où la distance entre la surface périphérique externe de l'électrode centrale et la surface périphérique interne de l'isolant est plus petite comme la seconde position, et la plage dans la direction circonférentielle entre deux tangentes tracées du centre de l'électrode centrale à l'électrode de masse comme la plage d'électrode de masse, alors la première position est positionnée à l'intérieur de la plage d'électrodes de masse, la seconde position est positionnée à l'extérieur de la plage d'électrode de masse, et la distance la plus courte entre la surface périphérique interne de l'électrode de masse et la surface périphérique externe de l'isolant est inférieure ou égale à 1 mm.
PCT/JP2018/033608 2017-10-06 2018-09-11 Bougie d'allumage WO2019069640A1 (fr)

Priority Applications (1)

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JP2018562269A JPWO2019069640A1 (ja) 2017-10-06 2018-09-11 点火プラグ

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JP2017-196257 2017-10-06
JP2017196257 2017-10-06

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60140391U (ja) * 1984-02-27 1985-09-17 トヨタ自動車株式会社 点火プラグ
JP2010062160A (ja) * 2007-09-13 2010-03-18 Ngk Spark Plug Co Ltd スパークプラグ
JP2011034959A (ja) * 2009-07-06 2011-02-17 Ngk Spark Plug Co Ltd スパークプラグ
JP2013055022A (ja) * 2011-09-06 2013-03-21 Ngk Spark Plug Co Ltd スパークプラグ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60140391U (ja) * 1984-02-27 1985-09-17 トヨタ自動車株式会社 点火プラグ
JP2010062160A (ja) * 2007-09-13 2010-03-18 Ngk Spark Plug Co Ltd スパークプラグ
JP2011034959A (ja) * 2009-07-06 2011-02-17 Ngk Spark Plug Co Ltd スパークプラグ
JP2013055022A (ja) * 2011-09-06 2013-03-21 Ngk Spark Plug Co Ltd スパークプラグ

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