[go: up one dir, main page]

US3857145A - Method of producing spark plug center electrode - Google Patents

Method of producing spark plug center electrode Download PDF

Info

Publication number
US3857145A
US3857145A US00277044A US27704472A US3857145A US 3857145 A US3857145 A US 3857145A US 00277044 A US00277044 A US 00277044A US 27704472 A US27704472 A US 27704472A US 3857145 A US3857145 A US 3857145A
Authority
US
United States
Prior art keywords
metal
good heat
heat conducting
corrosion
conducting metal
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.)
Expired - Lifetime
Application number
US00277044A
Other languages
English (en)
Inventor
T Yamaguchi
K Izumi
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.)
Denso Corp
Original Assignee
NipponDenso 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
Application filed by NipponDenso Co Ltd filed Critical NipponDenso Co Ltd
Application granted granted Critical
Publication of US3857145A publication Critical patent/US3857145A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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

Definitions

  • the present invention relates to a method for the production of a spark plug center electrode of the type in which the core member consisting of a good heat conducting metal such as copper is inserted into the central part of the covering member consisting of a corrosion-resistant metal such as nickel.
  • the covering member is formed by boring out a rod of corrosion-resistant metal such as nickel and the core member consisting of a good heat conducting metal such as copper is then inserted into the bore of the covering member and soldered thereto, or alternatively two cylindrical metal pieces of corrosion-resistant metal and good heat conducting metal, respectively, are put one upon another so that when they are extruded and shaped into a rod form in a cold extrusion die, the core member of good heat conducting metal is covered by the covering member of corrosion-resistant metal by virtue of the flowing effect of the metal.
  • a disadvantage of the former method is that the bore of the corrosion-resistant metal covering member for receiving the core member made of good heat conducting metal is formed by a cutting process and thus this method is not satisfactory from the standpoint of mass production efficiency.
  • the latter method is also disadvantageous in that since the center electrode is made using two cylindrical metal pieces, as shown in FIG. 1, there is a limit to the length a of the corrosion-resistant metal covering member 2b covering the core member and moreover the covering member 2b increases toward its end at the sparking side and decreases toward the opposite end in its thickness b thereby making it impossible to ensure a uniform heat radiation.
  • a method of producing a spark plug center electrode which comprises a first step of forming a metal piece of good heat conductivity into a convex shape and a corrosion-resistant metal piece into a concave shape, a second step of preparing an extrusion material by fitting the protruding portion of the convex-shaped good heat conducting metal piece into the recessed portion of the concave-shaped corrosionresistant metal piece, a third step of cold-extruding the extrusion material into a rod form with the corrosionresistant metal covering the good heat conducting metal, a fourth step of cutting the cold extruded material at that portion thereof where the corrosion resistant metal no longer covers the good heat conducting metal, and a fifth step of subjecting the center electrode composed of the core member consisting of the good heat conducting metal and the corrosion-resistant metal covering member to a heading operation to form thereon a collar for assembling it into a spark plug, whereby the
  • FIG. 1 is a longitudinal sectional view of a center electrode produced according to a conventional method of producing a spark plug center electrode.
  • FIG. 2 is a longitudinal sectional view of a good heat conducting metal piece employed in the method for the production of a spark plug center electrode according to the present invention.
  • FIG. 3 is a longitudinal sectional view of a corrosionresistant metal piece employed in the method for the production of a spark plug center electrode according to the present invention.
  • FIG. 4 is a longitudinal sectional view of an extrusion material prepared by assembling the good heat conducting metal piece of FIG. 2 and the corrosionresistant metal piece of FIG. 3.
  • FIG. 5 is a partial longitudinal sectional view of a cold extrusion die in which the extrusion material of FIG. 4 is placed.
  • FIG. 6 is a longitudinal sectional view of a center electrode with a head, which is produced by the cold extrusion die of FIG. 5.
  • FIG. 7 is a longitudinal sectional view of the center electrode of FIG. 6 with its head cut off.
  • FIG. 8 is a longitudinal sectional view showing a first embodiment of the center electrode of the invention produced by subjecting the center electrode of FIG. 7 to a heading operation to form a collar thereon.
  • FIG. 9 is a side view of the center electrode shown in FIG. 8.
  • FIG. 10 is a longitudinal sectional view showing a second embodiment of the center electrode of the invention produced by subjecting the center electrode of FIG. 7 to a heading operation to form a collar thereon.
  • FIG. 11 is a longitudinal sectional view of the center electrode of FIG. 10 subjected to an expanding operation.
  • FIG. 12 is a side view of the center electrode shown in FIG. 11.
  • the first step consists of plastic-working a metal piece I of good heat conductivity such as copper into a convex shape having a protruding portion In as shown in FIG. 2 and a metal piece 2 of corrosion-resistant material such as nickel into a concave shape having a recessed portion 2a as shown in FIG. 3.
  • the good heat conducting metal piece] and the corrosionresistant metal piece 2 worked plastically in the first step are assembled in such a manner that the protruding portion la of the former is fitted into the recessed portion 2a of the latter to produce an extrusion material 3.
  • the two metal pieces 1 and 2 can be bonded together, if required, by means of soldering, welding, thermal diffusion, pressure fitting and caulking, etc., so that the resultant extrusion material 3 may be conveniently placed in a cold extrusion die in a subsequent step.
  • the extrusion material 3 prepared in the second step is placed in a cold extrusion die 4 and it is then shaped into a rod form in cold extrusion under the pressure applied by a punch 5, producing a cold extruded product comprising a covering member 2b consisting of the cup-shaped corrosionresistant metal piece 2 and a core member 1b consisting of the good heat conducting metal piece 1 covered by the covering member 2b.
  • a center electrode 6 is thus obtained in which, as shown in FIG.
  • the covering member 2b consisting of the corrosion-resistant metal 2 is uniform in its thickness b and its length a covering the core member lb is also long.
  • the center electrode 6 extruded as shown in FIG. 6 by the cold extrusion die is cut at that portion thereof where the corrosion-resistant metal of the center electrode 6 no longer covers the good heat conducting metal, i.e., at a dotted line X by means of a lathe or the like, cutting off a head portion 7 of the center electrode 6 and thus shaping it into a form shown in FIG. 7.
  • the fifth and final step consists of subjecting the center electrode 6 to a heading operation to form thereon a collar portion 8 as shown in FIGS. 8 and 9 which is necessary for assembling the center electrode 6 into a spark plug.
  • the center electrode 8 is worked to have a point angle a at its end face and it is also worked by a punch having its end face formed with radial V-grooves.
  • the collar portion 8 in the heading operation may be formed on the center electrode 6 at a place slightly below its end face as shown in FIG. 10 and thereafter the end face may be subjected to an expanding operation by the aforesaid punch as shown in FIG. 11 or 12.
  • the method according to the present invention comprises the first step of forming a good heat conducting metal piece into a convex shape and a corrosion-resistant metal piece into a concave shape, the second step of preparing an extrusion material by fitting the protruding portion of the convex-shaped good heat conducting metal piece into the recessed portion of the concave-shaped corrosionresistant metal piece, the third step of shaping the extrusion material into a rod form by the process of cold extruding, the fourth step of cutting off the thus coldextruded product at that portion thereof where the corrosion-resistant metal no longer covers the good heat conducting metal, and the fifth step of subjecting the resultant center electrode comprising the core member made of the good heat conducting metal and the covering member made of the corrosion-resistant metal to a heading operation to form thereon a collar portion for assemblying the center electrode into a spark plug, there is a remarkable effect in that the dimensions of the protruding portion of the good heat conducting metal piece and the recessed portion of the corrosionresistant metal piece can be chosen
  • a method of producing a spark plug center electrode of the type which comprises a core member consisting of a good heat conducting metal having a corrosion-resistant metal enclosing the sparking end portion and the side portions thereof, said method comprising the steps of:
  • said good heat conducting metal into a protrudent shape by only one plastic-working step, the protrudent portion of the shaped good heat conducting metal being at least as great as one-half the height of said shaped good heat conducting metal,
  • a method according to claim 1 including a further step of cutting said cold-extruded product at that portion thereof where the length of said corrosion-resistant metal covering said good heat conducting metal terminates.
  • a method according to claim 2 including a further step of subjecting the center electrode comprising the core member consisting of said good heat conducting metal and the covering member covering said core member and consisting of said corrosion-resistant metal to a heading operation to form thereon a collar portion for assemblying said center electrode into a spark plug.
  • a method of producing a spark plug center electrode of the type which comprises a core member consisting of a good heat conducting metal having a corrosion-resistant metal enclosing the sparking end portion and the side portions thereof, said method comprising the steps of:
  • said good heat conducting metal into a protrudent shape by only one plastic-working step wherein the protruding portion of said good heat conducting metal is at least as great as one-half the length of the shaped good heat conducting metal,

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Spark Plugs (AREA)
  • Extrusion Of Metal (AREA)
  • Forging (AREA)
US00277044A 1972-04-14 1972-08-01 Method of producing spark plug center electrode Expired - Lifetime US3857145A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47038172A JPS48103445A (fr) 1972-04-14 1972-04-14

Publications (1)

Publication Number Publication Date
US3857145A true US3857145A (en) 1974-12-31

Family

ID=12517959

Family Applications (1)

Application Number Title Priority Date Filing Date
US00277044A Expired - Lifetime US3857145A (en) 1972-04-14 1972-08-01 Method of producing spark plug center electrode

Country Status (7)

Country Link
US (1) US3857145A (fr)
JP (1) JPS48103445A (fr)
BE (1) BE798232A (fr)
DE (1) DE2238283A1 (fr)
FR (1) FR2179758B1 (fr)
GB (1) GB1425126A (fr)
IT (1) IT983748B (fr)

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3036226A1 (de) 1979-10-15 1981-04-23 Champion Spark Plug Co., Toledo, Ohio Verfahren zum herstellen einer zuendkerzenelektrode aus verbundmaterial
EP0044764A1 (fr) * 1980-07-17 1982-01-27 Bendix Autolite Corporation Méthode de fabrication d'une électrode centrale pour utilisation dans une bougie d'allumage
US4314392A (en) * 1978-12-16 1982-02-09 Gkn Floform Limited Method of making a spark plug electrode
DE3118793A1 (de) 1980-05-30 1982-04-29 Champion Spark Plug Co., Toledo, Ohio Verfahren zur herstellung einer zusammengesetzten mittenelektrode fuer zuendkerzen
US4374450A (en) * 1979-06-04 1983-02-22 The Bendix Corporation Method of making an igniter plug with nickel coating on center electrode
DE3221663A1 (de) * 1981-10-29 1983-05-11 Champion Spark Plug Co., Toledo, Ohio Zuendkerze und verfahren zu ihrer herstellung
US4384234A (en) * 1979-12-07 1983-05-17 Texas Instruments Incorporated Spark plug with heat conducting sleeve for center electrode
US4410309A (en) * 1981-01-16 1983-10-18 G. Rau Gmbh & Co. Method of making a spark-plug center electrode
US4526551A (en) * 1980-05-30 1985-07-02 Champion Spark Plug Company Production of electrodes
US4575343A (en) * 1980-04-09 1986-03-11 The National Machinery Company Bimetal electrode and method of making same
US4585421A (en) * 1983-11-23 1986-04-29 The National Machinery Company Method of making copper-clad bimetal electrodes for spark plugs
US4606730A (en) * 1983-09-21 1986-08-19 The National Machinery Company Bimetal electrodes for spark plugs or the like and method of making same
US4684352A (en) * 1985-03-11 1987-08-04 Champion Spark Plug Company Method for producing a composite spark plug center electrode
EP0268757A1 (fr) * 1986-11-24 1988-06-01 Allied Corporation Méthode de fabrication d'une électrode centrale pour une bougie d'allumage
EP0270746A1 (fr) * 1986-11-24 1988-06-15 Allied Corporation Méthode de fabrication d'une électrode centrale pour une bougie d'allumage
US4808135A (en) * 1986-07-29 1989-02-28 Ngk Spark Plug Co., Ltd. Center electrode structure for spark plug
US4967116A (en) * 1987-12-10 1990-10-30 Ngk Spark Plug Co. Ltd. Spark plug having heat- and corrosion-resistant surface
US5107169A (en) * 1989-06-05 1992-04-21 G. Rau Gmbh & Co. Central electrode for spark plugs having an interlayer between the core and an outer layer
US5973443A (en) * 1996-05-06 1999-10-26 Alliedsignal Inc. Spark plug electrode tip for internal combustion engine
WO2000003465A1 (fr) * 1998-07-13 2000-01-20 Alliedsignal Inc. Electrode de bougie d'allumage possedant une sphere a base d'iridium et procede de fabrication de cette electrode
US6614145B2 (en) 2001-08-21 2003-09-02 Federal-Mogul World Wide, Inc. Two-piece swaged center electrode assembly
US20040078971A1 (en) * 2002-10-25 2004-04-29 Denso Corporation Method of manufacturing center electrode for spark plug
US20090189502A1 (en) * 2006-03-14 2009-07-30 Ngk Spark Plug Co., Ltd. Method of producing spark plug, and spark plug
RU2498469C1 (ru) * 2012-06-01 2013-11-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Уфимский государственный авиационный технический университет" Способ изготовления биметаллического центрального электрода искровой свечи зажигания двигателя внутреннего сгорания
CN104964158A (zh) * 2009-06-30 2015-10-07 瓦锡兰油气系统公司 用于存储和运输液化石油气的方法和系统
DE102018222331A1 (de) * 2018-12-19 2020-06-25 Robert Bosch Gmbh Zündkerzenelektrode mit Diffusionsschicht zwischen Elektrodenkern und Elektrodenmantel sowie Herstellungsverfahren

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2948511A1 (de) * 1979-12-01 1981-06-04 G. Rau GmbH & Co, 7530 Pforzheim Zuendkerzenmittelelektrode
GB2088753B (en) * 1980-12-10 1984-02-01 Gkn Floform Ltd Spark plug electrode
JP5639118B2 (ja) 2012-06-05 2014-12-10 日本特殊陶業株式会社 スパークプラグの製造方法
DE102014223746A1 (de) * 2014-11-20 2016-05-25 Robert Bosch Gmbh Zündkerze und Verfahren zur Herstellung einer Zündkerze

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB838682A (en) * 1957-09-25 1960-06-22 Gen Motors Corp Improvements in or relating to a method of making rod-shaped composite spark plug electrodes
US2955222A (en) * 1958-06-25 1960-10-04 Bosch Gmbh Robert Center electrode structure for spark plugs and process for making the same
US3144576A (en) * 1962-02-14 1964-08-11 Hagmaier Eugen Spark plug and method of manufacture
US3548472A (en) * 1967-11-15 1970-12-22 Hitachi Ltd Ignition plug and method for manufacturing a center electrode for the same

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH322355A (de) * 1953-06-06 1957-06-15 Bosch Gmbh Robert Verfahren und Vorrichtung zur Herstellung eines Mittelelektrodenteils für Zündkerzen
US3010196A (en) * 1957-09-25 1961-11-28 Gen Motors Corp Method for making composite metal members

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB838682A (en) * 1957-09-25 1960-06-22 Gen Motors Corp Improvements in or relating to a method of making rod-shaped composite spark plug electrodes
US2955222A (en) * 1958-06-25 1960-10-04 Bosch Gmbh Robert Center electrode structure for spark plugs and process for making the same
US3144576A (en) * 1962-02-14 1964-08-11 Hagmaier Eugen Spark plug and method of manufacture
US3548472A (en) * 1967-11-15 1970-12-22 Hitachi Ltd Ignition plug and method for manufacturing a center electrode for the same

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4314392A (en) * 1978-12-16 1982-02-09 Gkn Floform Limited Method of making a spark plug electrode
US4374450A (en) * 1979-06-04 1983-02-22 The Bendix Corporation Method of making an igniter plug with nickel coating on center electrode
DE3036226A1 (de) 1979-10-15 1981-04-23 Champion Spark Plug Co., Toledo, Ohio Verfahren zum herstellen einer zuendkerzenelektrode aus verbundmaterial
US4384234A (en) * 1979-12-07 1983-05-17 Texas Instruments Incorporated Spark plug with heat conducting sleeve for center electrode
US4575343A (en) * 1980-04-09 1986-03-11 The National Machinery Company Bimetal electrode and method of making same
DE3118793A1 (de) 1980-05-30 1982-04-29 Champion Spark Plug Co., Toledo, Ohio Verfahren zur herstellung einer zusammengesetzten mittenelektrode fuer zuendkerzen
US4526551A (en) * 1980-05-30 1985-07-02 Champion Spark Plug Company Production of electrodes
EP0044764A1 (fr) * 1980-07-17 1982-01-27 Bendix Autolite Corporation Méthode de fabrication d'une électrode centrale pour utilisation dans une bougie d'allumage
US4410309A (en) * 1981-01-16 1983-10-18 G. Rau Gmbh & Co. Method of making a spark-plug center electrode
DE3221663A1 (de) * 1981-10-29 1983-05-11 Champion Spark Plug Co., Toledo, Ohio Zuendkerze und verfahren zu ihrer herstellung
US4695759A (en) * 1981-10-29 1987-09-22 Champion Spark Plug Company Method for producing a composite center electrode and an electrode
US4606730A (en) * 1983-09-21 1986-08-19 The National Machinery Company Bimetal electrodes for spark plugs or the like and method of making same
US4585421A (en) * 1983-11-23 1986-04-29 The National Machinery Company Method of making copper-clad bimetal electrodes for spark plugs
US4684352A (en) * 1985-03-11 1987-08-04 Champion Spark Plug Company Method for producing a composite spark plug center electrode
US4808135A (en) * 1986-07-29 1989-02-28 Ngk Spark Plug Co., Ltd. Center electrode structure for spark plug
EP0270746A1 (fr) * 1986-11-24 1988-06-15 Allied Corporation Méthode de fabrication d'une électrode centrale pour une bougie d'allumage
EP0268757A1 (fr) * 1986-11-24 1988-06-01 Allied Corporation Méthode de fabrication d'une électrode centrale pour une bougie d'allumage
US4967116A (en) * 1987-12-10 1990-10-30 Ngk Spark Plug Co. Ltd. Spark plug having heat- and corrosion-resistant surface
US5107169A (en) * 1989-06-05 1992-04-21 G. Rau Gmbh & Co. Central electrode for spark plugs having an interlayer between the core and an outer layer
US5973443A (en) * 1996-05-06 1999-10-26 Alliedsignal Inc. Spark plug electrode tip for internal combustion engine
WO2000003465A1 (fr) * 1998-07-13 2000-01-20 Alliedsignal Inc. Electrode de bougie d'allumage possedant une sphere a base d'iridium et procede de fabrication de cette electrode
US6614145B2 (en) 2001-08-21 2003-09-02 Federal-Mogul World Wide, Inc. Two-piece swaged center electrode assembly
US20040078971A1 (en) * 2002-10-25 2004-04-29 Denso Corporation Method of manufacturing center electrode for spark plug
US7073256B2 (en) * 2002-10-25 2006-07-11 Denso Corporation Method of manufacturing center electrode for spark plug
US20110012499A1 (en) * 2006-03-14 2011-01-20 Ngk Spark Plug Co., Ltd. Method of producing spark plug, and spark plug
US20090189502A1 (en) * 2006-03-14 2009-07-30 Ngk Spark Plug Co., Ltd. Method of producing spark plug, and spark plug
US7896720B2 (en) * 2006-03-14 2011-03-01 Ngk Spark Plug Co., Ltd. Method of producing spark plug, and spark plug
US8188640B2 (en) 2006-03-14 2012-05-29 Ngk Spark Plug Co., Ltd. Spark plug center electrode with reduced cover portion thickness
CN104964158A (zh) * 2009-06-30 2015-10-07 瓦锡兰油气系统公司 用于存储和运输液化石油气的方法和系统
CN104964158B (zh) * 2009-06-30 2017-05-10 瓦锡兰油气系统公司 用于存储和运输液化石油气的方法和系统
US9810376B2 (en) 2009-06-30 2017-11-07 Wartsila Oil & Gas Systems As Method and system for storage and transport of liquefied petroleum gases
US9982844B2 (en) 2009-06-30 2018-05-29 Wärtsilä Oil & Gas Systems As Method and system for storage and transport of liquefied petroleum gases
US10006589B2 (en) 2009-06-30 2018-06-26 Wärtsilä Oil & Gas Systems As Method and system for storage and transport of liquefied petroleum gases
RU2498469C1 (ru) * 2012-06-01 2013-11-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Уфимский государственный авиационный технический университет" Способ изготовления биметаллического центрального электрода искровой свечи зажигания двигателя внутреннего сгорания
DE102018222331A1 (de) * 2018-12-19 2020-06-25 Robert Bosch Gmbh Zündkerzenelektrode mit Diffusionsschicht zwischen Elektrodenkern und Elektrodenmantel sowie Herstellungsverfahren

Also Published As

Publication number Publication date
DE2238283A1 (de) 1973-10-25
FR2179758B1 (fr) 1977-02-04
IT983748B (it) 1974-11-11
FR2179758A1 (fr) 1973-11-23
JPS48103445A (fr) 1973-12-25
GB1425126A (en) 1976-02-18
BE798232A (fr) 1973-07-31

Similar Documents

Publication Publication Date Title
US3857145A (en) Method of producing spark plug center electrode
US3803892A (en) Method of producing spark plug center electrode
JP6294921B2 (ja) 金属材料ブッシング
US20060222881A1 (en) Metal fixing material bushing and method for producing a base plate of a metal fixing material bushing
US4684352A (en) Method for producing a composite spark plug center electrode
CN212441127U (zh) 一种合成异形复合片的组装块装置
EP2254713B1 (fr) Procédé de création d'un boîtier d'armature
US3818555A (en) Method of manufacturing central electrode for spark plug
US2755368A (en) Welding method
US4410309A (en) Method of making a spark-plug center electrode
US4943687A (en) Current collecting unit
JPS63224822A (ja) 板材に有頭軸を固着する方法
US1369927A (en) Method of manufacturing rail-bonds
EP0579400B1 (fr) Boucle d'oreille à boule et son procédé de fabrication
JPH05343159A (ja) スパークプラグの放電電極の製作方法
JP2700303B2 (ja) 圧着又は圧縮端子の製造方法
JPH01144530A (ja) モールド挿入型電気接点の製造方法
GB2091600A (en) Spark-plug Centre Electrode and Method of Making Same
JPS59101787A (ja) 配線基板に植設する端子とろう材との複合体の製造方法
SU599904A1 (ru) Способ изготовлени деталей с глубокими,узкими глухими полост ми
JPH05144545A (ja) スパークプラグ中心電極の製造方法
JP2805807B2 (ja) 点火プラグの複合接地電極及びその製造方法
JP3140065B2 (ja) スパークプラグ用中心電極の製造方法
JPH0829391B2 (ja) ホース口金具の製造方法
SU1644307A1 (ru) Полюсный башмак генератора и способ его изготовлени