EP0975075A2 - Herstellungsverfahren einer Zündkerze - Google Patents

Herstellungsverfahren einer Zündkerze Download PDF

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Publication number
EP0975075A2
EP0975075A2 EP99122560A EP99122560A EP0975075A2 EP 0975075 A2 EP0975075 A2 EP 0975075A2 EP 99122560 A EP99122560 A EP 99122560A EP 99122560 A EP99122560 A EP 99122560A EP 0975075 A2 EP0975075 A2 EP 0975075A2
Authority
EP
European Patent Office
Prior art keywords
central electrode
chip
spark plug
producing
alloy including
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP99122560A
Other languages
English (en)
French (fr)
Other versions
EP0975075A3 (de
Inventor
Watarui c/o NGK Spark Plug Co. Ltd. Matsutani
Junichi C/O Ngk Spark Plug Co. Ltd. Kagawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Niterra Co Ltd
Original Assignee
NGK Spark Plug Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=26504866&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0975075(A2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by NGK Spark Plug Co Ltd filed Critical NGK Spark Plug Co Ltd
Publication of EP0975075A2 publication Critical patent/EP0975075A2/de
Publication of EP0975075A3 publication Critical patent/EP0975075A3/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T21/00—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs
    • H01T21/02—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs of sparking plugs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/39—Selection of materials for electrodes

Definitions

  • the present invention relates to a method for producing a spark plug for use in internal combustion engines.
  • Ir is easy to oxidize and evaporate in a high temperature range of 900 to 1,000°C. Therefore, if it is directly used in the igniting portion of the electrode, it is more consumed by oxidation and evaporation than by spark. Therefore, the spark plug using Ir in the igniting portion of an electrode is highly durable under low-temperature conditions as in driving on city roads but their endurance drops considerably during continuous running at high speed.
  • the above object is achieved by the subject matter of claim 1.
  • a spark plug produced according to the present invention is comprised of: a central electrode; an insulator provided exterior to the central electrode; a main metallic shell provided exterior to the insulator; a ground electrode coupled at one end to the main metallic shell and which has the other end disposed to face the central electrode; and an igniting portion that is secured to at least one of the central electrode and the ground electrode for forming a spark discharge gap; wherein the igniting portion is made of an alloy based on Ir which contains Rh in an amount ranging from 3 to 50 wt% (50 wt% being not inclusive).
  • the igniting portion of an electrode which forms a spark discharge gap is made of an alloy that is mainly made of Ir and which contains an amount of Rh in the stated range. Therefore, the consumption due to oxidation and evaporation of the Ir component at high temperatures is effectively retarded to thereby realize a highly durable spark plug.
  • the spark plug manufactured according to the present invention has a central electrode, an insulator provided exterior to the central electrode, a main metallic shell provided exterior to the insulator, a ground electrode coupled at one end to the main metallic shell and which has the other end disposed to face the central electrode, and an igniting portion that is secured to either the central electrode or the ground electrode or both for forming a spark discharge gap, wherein the igniting portion is made of an alloy based on Ir which contains Rh in an amount ranging from 3 to 50 wt% (50 wt% being not inclusive).
  • the present inventors have found that if the igniting portion of an electrode which forms a spark discharge gap is made of an alloy that is mainly made of Ir and which contains an amount of Rh in the stated range, the consumption due to oxidation and evaporation of the Ir component at high temperatures is effectively retarded to thereby realize a highly durable spark plug.
  • a chip made of a metal having the stated composition may be joined by welding to the ground electrode and/or the central electrode.
  • the term "igniting portion" as used herein shall refer to that part of the joined chip which has not been subject to the effect of the compositional change due to welding (e.g., the portion other than that which has been alloyed with the constituent material of the ground or central electrode upon welding).
  • the Rh content of the alloy is less than 3%, the effectiveness of Rh in retarding the oxidation and evaporation of Ir is insufficient to prevent premature consumption of the igniting portion. Hence, the endurance of the spark plug is reduced. In this case, the igniting portion is consumed primarily in the tip end face of the chip welded to the central electrode and/or the ground electrode. However, the lateral sides of the chip may also be consumed if the Rh content is reduced.
  • the Rh content of the alloy is desirably adjusted to lie within such a range that the consumption of the igniting portion is unlikely to occur not only in the tip end face of the chip but also on its lateral sides.
  • the Rh content of the alloy is 50 wt% or more, the melting point of the alloy will drop and the endurance of the spark plug will deteriorate accordingly.
  • the Rh content of the alloy is preferably adjusted to lie within the range of 3 to 50 wt% (50 wt% being not inclusive), desirably 7 to 30 wt%, more desirably 15 to 25 wt%, most desirably 18 to 22 wt%.
  • a spark plug 100 has a tubular main metallic shell 1, an insulator 2 fitted into the metallic shell 1 in such a way that the tip end 21 protrudes from the metallic shell 1, a central electrode 3 provided within the insulator 2 in such a way that the igniting portion 31 formed at the tip end protrudes from the insulator 2, and a ground electrode 4 coupled at one end to the main metallic shell 1 as by welding and which has the other end bent laterally such that its lateral side faces the tip end of the central electrode 3.
  • the ground electrode 4 has an igniting, portion 32 formed in such a way that it faces the igniting portion 31 of the central electrode 3; the clearance between the two igniting portions 31 and 32 forms a spark discharge gap g.
  • the insulator 2 is a sinter of a ceramic material such as alumina or aluminum nitride as a main constituent, and it has an axial bore 6 through which the central electrode 3 is to be fitted.
  • the main metallic shell 1 is a cylinderical form made of a metal such as a low-carbon steel and which provides a housing for the spark plug 100.
  • the circumference of the metallic shell 1 has a threaded portion 7 formed to assist in the mounting of the spark plug 100 on an engine block (not shown).
  • the main body 3a of the central electrode 3 and the main body 4a of the ground electrode 4 are both typically made of a Ni alloy.
  • the igniting portion 31 of the central electrode 3 and the opposed firing portion 32 of the ground electrode 4 are both made of an alloy based on Ir and which contains Rh in an amount ranging from 3 to 50 wt% (50 wt% being not inclusive).
  • the Rh content of the alloy is desirably adjusted to lie within a range of 7 to 30 wt%, more desirably 15 to 25 wt%, most desirably 18 to 22 wt%.
  • the main body 3a of the central electrode 3 tapers at the tip end and its tip end face is formed flat.
  • a disk-shaped chip having an alloy formula for the igniting portion 31 is placed on the flat tip end face and laser welding, electron beam welding, resistance welding or other suitable welding technique is applied to the periphery of the joined surfaces to form a weld line W, whereby the chip is securely fixed to the tip end face of the central electrode 3 to form the igniting portion 31.
  • a similar chip is placed on the ground electrode 4 in registry with the position of the igniting portion 31 and a weld line W is similarly formed on the periphery of the joined surfaces, whereby the chip is securely fitted to the ground electrode 4 to form the igniting portion 32.
  • the chips may be formed from a molten material obtained by mixing the necessary alloy ingredients to give the stated formula and melting the mixture; alternatively, the chips may be formed from a sinter obtained by shaping into a compact a suitable alloy powder or a mixture of the powders of elemental metal components in specified proportions and sintering the compact.
  • a raw material made of the molten alloy may be subjected to a working process including at least one of rolling, forging, drawing, cutting, shearing and blanking steps, whereby the chips are produced in a specified shape. Steps such as rolling, forging and cutting may be performed with the alloy being heated to a specified temperature (to effect "hot” or “warm” working). The temperature for these steps which is variable with the alloy composition may typically be at least 700°C.
  • a molten alloy may be hot rolled to a sheet, which is hot blanked to chips of a specified shape; alternatively, the molten alloy may be hot rolled or forged to a wire or rod shape, which is cut to chips of a specified length.
  • the iridium (Ir) which is the chief component of the chips has low ductility or malleability in its elemental form; however, in the presence of added Rh, the workability of the Ir is improved such that the resulting alloy can be rolled or forged into a sheet, a rod or a wire with great ease compared to the case where Rh is not added.
  • defects such as cracking are less likely to occur in the raw alloy material being in the process of rolling or forging and this in turn contributes to improvements in the efficiency of chip production and the materials yield. It should be noted here that the workability of the raw alloy material will increase with increasing Rh addition.
  • either one of the two opposed igniting portions 31 and 32 may be omitted. If this is the case, the spark discharge gap g is formed between the igniting portion 31 (or the opposed igniting portion 32) and the ground electrode 4 (or the central electrode 3).
  • the spark plug 100 operates according to the following mode of action.
  • the spark 100 is fitted on an engine block by means of the threaded portion 7 and used as a source to ignite an air-fuel mixture that is supplied into the combustion chamber.
  • the igniting portion 31 and the opposed igniting portion 32 define the spark discharge gap g; since both igniting portions are made of the aforementioned alloy, their consumption due to the oxidation and evaporation of Ir is sufficiently retarded to ensure that the spark discharge gap g will not increase for a prolonged period, thereby extending the life of the spark plug 100.
  • the result is shown in Fig. 3 in terms of the relationship between the Rh content of the alloy and the increase in the spark discharge gap.
  • the result is shown in Fig. 5 in terms of the relationship between the Rh content of the alloy and the increase in the spark discharge gap.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Spark Plugs (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
EP99122560A 1996-06-28 1997-06-27 Herstellungsverfahren einer Zündkerze Withdrawn EP0975075A3 (de)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP18834796 1996-06-28
JP18834796 1996-06-28
JP33511996A JP3461670B2 (ja) 1996-06-28 1996-11-28 スパークプラグ及びその製造方法
JP33511996 1996-11-28
EP97110583A EP0817341B2 (de) 1996-06-28 1997-06-27 Zündkerze

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP97110583A Division EP0817341B2 (de) 1996-06-28 1997-06-27 Zündkerze

Publications (2)

Publication Number Publication Date
EP0975075A2 true EP0975075A2 (de) 2000-01-26
EP0975075A3 EP0975075A3 (de) 2000-02-02

Family

ID=26504866

Family Applications (2)

Application Number Title Priority Date Filing Date
EP97110583A Expired - Lifetime EP0817341B2 (de) 1996-06-28 1997-06-27 Zündkerze
EP99122560A Withdrawn EP0975075A3 (de) 1996-06-28 1997-06-27 Herstellungsverfahren einer Zündkerze

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP97110583A Expired - Lifetime EP0817341B2 (de) 1996-06-28 1997-06-27 Zündkerze

Country Status (6)

Country Link
US (1) USRE43758E1 (de)
EP (2) EP0817341B2 (de)
JP (1) JP3461670B2 (de)
KR (1) KR100355886B1 (de)
CN (1) CN1059293C (de)
DE (1) DE69703011T3 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002231412A (ja) * 2001-01-31 2002-08-16 Ngk Spark Plug Co Ltd スパークプラグの製造方法及び製造装置
JP4121342B2 (ja) * 2001-11-13 2008-07-23 日本特殊陶業株式会社 クロメート被膜付きプラグ用金属部品及びその製造方法
EP2259394B1 (de) * 2008-03-27 2018-09-05 NGK Spark Plug Co., Ltd. Zündkerze und verfahren zur herstellung der zündkerze
DE102010032412B4 (de) * 2010-07-27 2012-03-08 Dkt Verwaltungs-Gmbh Verfahren zum Herstellen einer Zündelektrode für eine Vorkammerzündkerze und Vorkammerzündkerze
JP7057935B2 (ja) * 2016-12-22 2022-04-21 石福金属興業株式会社 耐熱性Ｉｒ合金

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0243529A1 (de) * 1986-03-28 1987-11-04 NGK Spark Plug Co. Ltd. Zündkerze
EP0418055A1 (de) * 1989-09-14 1991-03-20 Ngk Spark Plug Co., Ltd Zündkerze
EP0587446A1 (de) * 1992-09-10 1994-03-16 Ngk Spark Plug Co., Ltd Herstellungsverfahren für Zündkerze
EP0637113A1 (de) * 1993-07-26 1995-02-01 Ngk Spark Plug Co., Ltd Zündkerze
GB2302367A (en) * 1995-06-15 1997-01-15 Nippon Denso Co I.c. engine spark plug with noble metal chip of Ir-Rh alloy

Family Cites Families (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1850819A (en) 1931-03-06 1932-03-22 Wilson H A Co Alloy
GB479540A (en) † 1936-09-30 1938-02-08 Alan Richard Powell Improvements in electrodes for sparking plugs
US4324588A (en) 1979-08-17 1982-04-13 Engelhard Corporation Arc erosion resistant composite materials and processes for their manufacture
JPS57130384A (en) 1981-02-04 1982-08-12 Nippon Denso Co Spark plug for internal combustion engine
US4699600A (en) 1981-04-30 1987-10-13 Nippondenso Co., Ltd. Spark plug and method of manufacturing the same
US4700103A (en) 1984-08-07 1987-10-13 Ngk Spark Plug Co., Ltd. Spark plug and its electrode configuration
JPS6258114A (ja) 1985-09-09 1987-03-13 Toshiba Corp ロ−ドサ−ベイシステム
DE3725228A1 (de) 1987-07-30 1989-02-09 Bayer Ag Verfahren zur gewinnung von reinen aromaten
CN1009840B (zh) * 1988-10-14 1990-10-03 中国有色金属工业总公司昆明贵金属研究所 火花塞用铂基合金
JPH03110779A (ja) 1989-09-25 1991-05-10 Ngk Spark Plug Co Ltd 光センサ内蔵型スパークプラグ
JPH04329286A (ja) 1991-04-30 1992-11-18 Nippondenso Co Ltd スパークプラグの製造方法
JP2902186B2 (ja) 1991-12-04 1999-06-07 日本特殊陶業株式会社 気体燃料機関用スパークプラグ
JPH05335066A (ja) 1992-06-01 1993-12-17 Nippondenso Co Ltd 内燃機関用スパークプラグ
JP2853108B2 (ja) 1992-06-17 1999-02-03 日本特殊陶業 株式会社 スパークプラグ
US5320569A (en) 1992-07-27 1994-06-14 Ngk Spark Plug Co., Ltd. Method of making a spark plug
GB2269632B (en) * 1992-08-12 1996-04-17 Nippon Denso Co Method of manufacturing a discharge electrode assembly or a spark plug
JP3265067B2 (ja) 1993-07-23 2002-03-11 日本特殊陶業株式会社 スパークプラグ
JPH0737673A (ja) 1993-07-23 1995-02-07 Ngk Spark Plug Co Ltd スパークプラグ用電極
JPH07268574A (ja) 1994-03-25 1995-10-17 Tanaka Kikinzoku Kogyo Kk イリジウム線の製造方法
JP3562533B2 (ja) 1994-08-03 2004-09-08 株式会社デンソー 内燃機関用スパークプラグ
GB9418705D0 (en) † 1994-09-16 1994-11-16 Johnson Matthey Plc Improvements in high temperature articles
JP2877035B2 (ja) 1995-06-15 1999-03-31 株式会社デンソー 内燃機関用スパークプラグ
JPH09219274A (ja) * 1995-12-06 1997-08-19 Denso Corp スパークプラグ
US5973443A (en) 1996-05-06 1999-10-26 Alliedsignal Inc. Spark plug electrode tip for internal combustion engine
JP3000955B2 (ja) 1996-05-13 2000-01-17 株式会社デンソー スパークプラグ
GB2479540A (en) 2010-04-13 2011-10-19 Adam Ford Corrupting and erasing data on a storage device when computer casing is broken

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0243529A1 (de) * 1986-03-28 1987-11-04 NGK Spark Plug Co. Ltd. Zündkerze
EP0418055A1 (de) * 1989-09-14 1991-03-20 Ngk Spark Plug Co., Ltd Zündkerze
EP0587446A1 (de) * 1992-09-10 1994-03-16 Ngk Spark Plug Co., Ltd Herstellungsverfahren für Zündkerze
EP0637113A1 (de) * 1993-07-26 1995-02-01 Ngk Spark Plug Co., Ltd Zündkerze
GB2302367A (en) * 1995-06-15 1997-01-15 Nippon Denso Co I.c. engine spark plug with noble metal chip of Ir-Rh alloy

Also Published As

Publication number Publication date
DE69703011T2 (de) 2001-01-11
EP0975075A3 (de) 2000-02-02
CN1170980A (zh) 1998-01-21
JPH1074575A (ja) 1998-03-17
EP0817341B2 (de) 2003-12-10
KR980006677A (ko) 1998-03-30
EP0817341A1 (de) 1998-01-07
DE69703011T3 (de) 2004-05-27
DE69703011D1 (de) 2000-10-12
EP0817341B1 (de) 2000-09-06
JP3461670B2 (ja) 2003-10-27
KR100355886B1 (ko) 2002-12-26
CN1059293C (zh) 2000-12-06
USRE43758E1 (en) 2012-10-23

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