EP0101547A2 - High-tension spark plug - Google Patents

High-tension spark plug Download PDF

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Publication number
EP0101547A2
EP0101547A2 EP83106476A EP83106476A EP0101547A2 EP 0101547 A2 EP0101547 A2 EP 0101547A2 EP 83106476 A EP83106476 A EP 83106476A EP 83106476 A EP83106476 A EP 83106476A EP 0101547 A2 EP0101547 A2 EP 0101547A2
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EP
European Patent Office
Prior art keywords
end section
connection
electrical insulating
insulating body
longitudinal bore
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.)
Granted
Application number
EP83106476A
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German (de)
French (fr)
Other versions
EP0101547B1 (en
EP0101547A3 (en
Inventor
Walter Benedikt
Klaus-Dieter Dr. Pohl
Rudolf Pollner
Christian Dr. Dipl.-Ing. Schaffrin
Leo Steinke
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Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Filing date
Publication date
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Publication of EP0101547A2 publication Critical patent/EP0101547A2/en
Publication of EP0101547A3 publication Critical patent/EP0101547A3/en
Application granted granted Critical
Publication of EP0101547B1 publication Critical patent/EP0101547B1/en
Expired legal-status Critical Current

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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
    • 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 invention relates to a high-voltage spark plug according to the preamble of the main claim.
  • a high-voltage spark plug is already known (GB-PS 547 119), in which there is a relatively short center electrode made of platinum in the bottom of the combustion chamber on the longitudinal bore of the electrical insulating body of this spark plug; The central electrode is followed by a metal body in the longitudinal bore, which is pressed against the central electrode and the wall of the longitudinal bore at temperatures in the range from 900 to 950 degrees Celsius during the assembly of the spark plugs.
  • An electrically conductive glass fusible link is then arranged in the longitudinal bore in a known manner on the connection-side end of the metal body. The close contact between the metal body and the center electrode or the longitudinal bore wall serves for good heat dissipation from the ignition area of the spark plug.
  • the high-voltage spark plug according to the invention with the characterizing features of the main claim has the advantage that it is easier and cheaper to assemble in the area of its electrical insulating body, its central electrode, its metal body and its casting compound, and that it nevertheless fulfills the conditions with regard to its function (including heat dissipation) and service life able to fulfill.
  • FIG. 1 shows the side view of an enlarged high-voltage spark plug in half section
  • FIG. 2 shows the section through the combustion chamber-side section of the electrical insulating body with the central electrode, metal body, sealing compound and part of the connecting bolt, which is shown further enlarged.
  • the high-voltage spark plug 10 shown in FIGS. 1 and 2 has an essentially tubular metal housing 11 which has a screw-in screw on its outside winch 12, a key hexagon 13 and a sealing seat 14 as a means for installing the spark plug 10 in an engine head, not shown; In the region of its end on the combustion chamber side, this housing 11 has a ground electrode 15, which in the present example is designed as a welded wire, but can also be of a different configuration.
  • the metal housing 11 comprises in its step-shaped through bore 16 in a known manner a rotationally symmetrical electrical insulating body 17.
  • This electrical insulating body 17 which for example essentially consists of aluminum oxide, has a so-called head 17/1 on the connection side, with a collar 17/2 in the direction of the combustion chamber Connect collar 17/3 and a foot 17/4.
  • This electrical insulating body 17 lies with a shoulder 18, which is formed between the foot 17/4 and the collar shoulder 17/3, on a shoulder 19 in the through bore 16 of the metal housing 11;
  • a sealing ring 20 is usually arranged between the shoulder 18 and the shoulder 19.
  • the connection-side area of the metal housing 11 is shaped as a flanged edge 23 over this sealing ring 22.
  • the electrical insulating body 17 is held firmly and tightly in the metal housing 11.
  • the electrical insulating body 17 can also be fixed in a sealing manner in the metal housing 11 by cementing or the like.
  • the electrical insulating body 17 has, in a known manner, a step-shaped longitudinal bore 24 which has a larger diameter in its connection-side area - the so-called head bore 24/1 - than the area on the combustion chamber side - the so-called foot bore 24/2; the foot hole 24/2 begins approximately in the area of the shoulder 17/3.
  • the foot bore 24/2 is closed by means of a molded-on, thin-walled base 25, in which there is a central electrode 26 made of precious metal or containing precious metal.
  • This center electrode 26 is preferably made of platinum or a platinum metal, extends coaxially to the longitudinal bore 24 of the electrical insulating body 17 and has a diameter of 0.3 mm; the maximum diameter of such a metallic center electrode is 0.5 mm.
  • the bottom 25 of the electrical insulating body 17 is only 1.5 mm thick, but can also be made thicker or thinner if necessary.
  • the center electrode 26 passing through this base 25 is sintered into the base 25 without a gap in the present example and protrudes 0.5 mm on the connection side into the foot bore 24/2 of the electrical insulating body 17; depending on the embodiment, the connection-side end section of the center electrode 26 can also protrude up to 1 mm into the foot bore 24/2.
  • the center electrode 26, which can alternatively be installed without a gap in the bottom 25 of the electrical insulating body 17 by means of putty, glass or the like, closes flush with the end face 27 of the electrical insulating body 17 in the present example and stands at a distance - the so-called spark gap 28 - the free end section opposite the ground electrode 15.
  • the end section of the center electrode 26 on the combustion chamber side can also be of a different configuration.
  • the center electrode 26 shown with its diameter of 0.3 mm has a total length of 2 mm and is preferably sintered into the base 25 of the electrical insulating body 17 as a pin; depending on the selected thickness of the bottom 25 of the electrical insulating body 17 - preferably it is between 1 and 2.5 mm dic-k - the length of the center electrode 26 is also selected, which will then be between 1 and 3 mm.
  • the center electrode 26 can, however, also be introduced as a platinum suspension in a preformed bore in this area with a small diameter of the electrical insulation body 17 that has not yet been sintered, and can then be finish-sintered with the insulation body 17.
  • the connection-side area of the center electrode 26 is provided with a recess 29 which is arranged axially to the center electrode 26 and is preferably of a conical or similar shape.
  • this recess 29 which according to the present example is 0.3 mm deep, the point 30 of a metal body 31 serving as a contact pin projects;
  • This metal body 31 with its taper 30 located on the combustion chamber side is preferably of circular cross-section, consists of a relatively inexpensive material, but has good thermal conductivity, high corrosion resistance (with sufficient electrical conductivity of scale layers being formed), high corrosion resistance to prevent spark gaps and a coefficient of thermal expansion that is adapted to the ceramic material of the electrical insulating body 17.
  • This metal body 31 can for example consist of a nickel alloy, which is known under the trade name Vacon 20 (company VAC-Hanau), has a diameter of the order of 1.5 to 2.5 mm and extends with its connection-side End portion somewhat in the head bore 24/1 of the electrical insulating body 17.
  • a head 32 is formed on the connection-side end portion of the metal body 31, which is provided with a taper 33 pointing towards the connection area.
  • the head 32 of the metal body 31 lies closely in the foot hole 24/2 of the electrical insulating body 17; the end section of the metal body 31 on the combustion chamber side is additionally fixed in a guide part 24/2 'of the foot bore 24/2.
  • connection-side end section of the metal body 31 including the taper 33 of its head 32 and the connection-side region of the head bore 24/1 of the insulating body 17 is filled with an electrically conductive casting compound 34; such casting compounds 34 are known per se (e.g. DE-PS 1 206 209, US-PS 2 106 578) and can additionally also contain layers (not shown) acting as electrical resistance (US-PS 3 903 453).
  • connection bolt 36 On the connection side protrudes into this potting compound 34 the connection bolt 36 provided on the combustion chamber side with an anchoring 35 (eg thread or cross knurling);
  • This connecting bolt 36 is made of unalloyed steel, rests with a collar 37 on the end face 38 of the electrical insulating body 17 and has a connecting thread 39 which protrudes from the electrical insulating body 17 on the connection side.
  • the metal body 31 which, depending on the embodiment of the spark plug 10, is between 8 and 20 mm long, not only is expensive material saved for central electrodes 26 which contain or contain noble metal, but it is also avoided that casting compounds 34 are in an area of the spark plug 10 are arranged in which they occur due to high operating temperatures Melted in the combustion chamber (not shown) of internal combustion engines and, as a result, may be adversely affected. For this reason, the length of the metal body 31 is chosen such that the casting compound 34 always remains safely below the transformation range of the selected, electrically conductive casting compound 34 at all operating temperatures occurring in this area.
  • the metal body 31 usually has a length between 8 and 20 mm and usually a diameter on the order of 1 to 2.5 mm.
  • the metal body 31 has a diameter of 1.5 mm, a head diameter of 2 mm and an overall length of 12 mm. While the head bore 24/1 of the electrical insulating body 17 has a diameter of 4.5 mm, the diameter of the foot bore 24/2 is 2.1 mm and the diameter of the guide part 24/2 'of the foot bore 24/2 is 1.53 mm.
  • the metal body 31 is inserted into the longitudinal bore 24 of the electrical insulating body 17 at room temperature and pressed against the connection-side end section of the center electrode 26 at approximately 100 N; this pressure is sufficient to form the recess 29 in this area of the central electrode 26.
  • the connecting bolt 36 is also pressed into the casting compound 34, in which it is held securely and with good electrical contact as a result of its anchoring means 35.
  • the metal body 31 is only partially in close contact with the electrical insulating body 17, it has been found that the heat generated in the area of the central electrode 26 is sufficiently dissipated to the electrical insulating body 17 in all operating states.

Abstract

1. High-tension spark plus (10), with a metal, substantially tubular shell (11), which has on its outside means (12, 13, 14) for fitting in an internal combustion engine, encloses and seals in its through-hole (16) a substantially rotationally symmetrical, preferably sintered electrical insulator (17) and has on its end section, on the combustion chamber side, an earth electrode (15), which is spaced (spark gap 28) opposite a relatively short centre electrode (26) which is made of precious metal or contains precious metal and is fixed with no play and in sealed manner in the bottom (25), on the combustion chamber side, of the stepped longitudinal hole (24) of the electrical insulator (17), has a smaller diameter than the steps (24/1, 24/2, 24/2"), extending on the terminal side, of the longitudinal hole (24), is in direct contact within the longitudinal hole (24) with a pinshaped metal body (31), which is laterally guided exactly in the longitudinal hole (24) of the electrical insulator (17) and the end section of which, on the terminal side, is contacted in a sealing manner to an electrically conductive casting compound (34) in the longitudinal hole (24), in which (casting compound 34) an end section of an electrically conductive terminal bolt (36) is also anchored, which protrudes with its other end section out of the end, on the terminal side, of the electrical insulator (17), characterized in that the metal body (31) has on the combustion chamber side an end section (30) which tapers toward the centre electrode (26) and is welded at least partially in a depression (29) in the end section, on the terminal side, of the centre electrode (26).

Description

Die Erfindung geht aus von einer Hochspannungszündkerze nach der Gattung des Hauptanspruchs. Es ist schon eine Hochspannungszündkerze bekannt (GB-PS 547 119), bei der sich eine relativ kurze Mittelelektrode aus Platin in dem brennraumseitigen Boden der Längsbohrung des Elektroisolierkörpers dieser Zündkerze befindet; der Mittelelektrode schließt sich in der Längsbohrung ein Metallkörper an, welcher anläßlich der Zündkerzen-Montage bei Temperaturen im Bereich von 900 bis 950 Grad Celsius mittels eines Stempels gegen die Mittelelektrode und die Wandung der Längsbohrung gepreßt wird. Auf dem anschlußseitigen Ende des Metallkörpers ist in der Längsbohrung dann in bekannter Weise ein elektrisch leitender Glasschmelzschluß angeordnet. Der enge Kontakt zwischen dem Metallkörper und der Mittelelektrode bzw. der Längsbohrungs-Wandung dient der guten Wärmeableitung aus dem Zündbereich der Zündkerze.The invention relates to a high-voltage spark plug according to the preamble of the main claim. A high-voltage spark plug is already known (GB-PS 547 119), in which there is a relatively short center electrode made of platinum in the bottom of the combustion chamber on the longitudinal bore of the electrical insulating body of this spark plug; The central electrode is followed by a metal body in the longitudinal bore, which is pressed against the central electrode and the wall of the longitudinal bore at temperatures in the range from 900 to 950 degrees Celsius during the assembly of the spark plugs. An electrically conductive glass fusible link is then arranged in the longitudinal bore in a known manner on the connection-side end of the metal body. The close contact between the metal body and the center electrode or the longitudinal bore wall serves for good heat dissipation from the ignition area of the spark plug.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Hochspannungszündkerze mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß sie im Bereich ihres Elektroisolierkörpers, ihrer Mittelelektrode, ihres Metallkörpers und ihrer Vergußmasse einfacher und kostengünstiger zu montieren ist und daß sie dennoch die Bedingungen hinsichtlich ihrer Funktion (auch Wärmeableitung) und Lebensdauer zu erfüllen vermag.The high-voltage spark plug according to the invention with the characterizing features of the main claim has the advantage that it is easier and cheaper to assemble in the area of its electrical insulating body, its central electrode, its metal body and its casting compound, and that it nevertheless fulfills the conditions with regard to its function (including heat dissipation) and service life able to fulfill.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen der im Hauptanspruch angegebenen Hochspannungszündkerze möglich. Besonders vorteilhaft ist es, daß sich ohne besonderen zusätzlichen Aufwand eine Schweißverbindung zwischen Mittelelektrode und Metallkörper ergibt.The measures listed in the subclaims enable advantageous developments and improvements of the high-voltage spark plug specified in the main claim. It is particularly advantageous that there is a welded connection between the central electrode and the metal body without any special additional effort.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen Figur 1 die Seitenansicht einer vergrößert dargestellten Hochspannungszündkerze im Halbschnitt und Figur 2 den weiter vergrößert dargestellten Schnitt durch den brennraumseitigen Abschnitt des Elektroisolierkörpers mit Mittelelektrode, Metallkörper, Vergußmasse und einem Teil des Anschlußbolzens.An embodiment of the invention is shown in the drawing and explained in more detail in the following description. 1 shows the side view of an enlarged high-voltage spark plug in half section, and FIG. 2 shows the section through the combustion chamber-side section of the electrical insulating body with the central electrode, metal body, sealing compound and part of the connecting bolt, which is shown further enlarged.

Beschreibung des AusführungsbeispielesDescription of the embodiment

Die in den Figuren 1 und 2 dargestelle Hochspannungszündkerze 10 besitzt ein im wesentlichen rohrförmiges Metallgehäuse 11, das an seiner Außenseite ein Einschraubgewinde 12, ein Schlüsselsechskant 13 und einen Dichtsitz 14 als Mittel für den Einbau der Zündkerze 10 in einen nicht dargestellten Motorkopf aufweist; im Bereich seines brennraumseitigen Endes hat dieses Gehäuse 11 eine Masseelektrode 15, welche im vorliegenden Beispiel als angeschweißter Draht ausgebildet ist, jedoch auch von anderer Konfiguration sein kann. Das Metallgehäuse 11 umfaßt in seiner stufenförmigen Durchgangsbohrung 16 in bekannter Weise einen rotationssymmetrischen Elektroisolierkörper 17. Dieser Elektroisolierkörper 17, der beispielsweise im wesentlichen aus Aluminiumoxid besteht, hat anschlußseits einen sogenannten Kopf 17/1, welchem sich in Richtung Brennraum ein Bund 17/2, ein Bundansatz 17/3 und ein Fuß 17/4 anschließen. Dieser Elektroisolierkörper 17 liegt mit einer Schulter 18, welche zwischen dem Fuß 17/4 und dem Bundansatz 17/3 gebildet ist, auf einem Absatz 19 in der Durchgangsbohrung 16 des Metallgehäuses 11; üblicherweise ist zwischen der Schulter 18 und dem Absatz 19 ein Dichtring 20 angeordnet. Auf der anschlußseitigen Schulter 21, die zwischen dem Kopf 17/1 und dem Bund 17/2 des Elektroisolierkörpers 17 gebildet ist, liegt üblicherweise auch ein Dichtring 22; über diesem Dichtring 22 ist der anschlußseitige Bereich des Metallgehäuses 11 als Bördelrand 23 geformt. Infolge der beschriebenen Fixierung des Elektroisolierkörpers 17 im Gehäuse 11 und zusätzlich mittels des bekannten Warmschrumpfprozesses (US-PS 2 111 916) ist der Elektroisolierkörper 17 fest und dicht im Metallgehäuse 11 gehalten. Anstelle der Anwendung dieses Bördel- und Warmschrumpfprozesses kann der Elektroisolierkörper 17 aber auch durch Einkitten oder ähnliches im Metallgehause 11 abdichtend festgelegt werden.The high-voltage spark plug 10 shown in FIGS. 1 and 2 has an essentially tubular metal housing 11 which has a screw-in screw on its outside winch 12, a key hexagon 13 and a sealing seat 14 as a means for installing the spark plug 10 in an engine head, not shown; In the region of its end on the combustion chamber side, this housing 11 has a ground electrode 15, which in the present example is designed as a welded wire, but can also be of a different configuration. The metal housing 11 comprises in its step-shaped through bore 16 in a known manner a rotationally symmetrical electrical insulating body 17. This electrical insulating body 17, which for example essentially consists of aluminum oxide, has a so-called head 17/1 on the connection side, with a collar 17/2 in the direction of the combustion chamber Connect collar 17/3 and a foot 17/4. This electrical insulating body 17 lies with a shoulder 18, which is formed between the foot 17/4 and the collar shoulder 17/3, on a shoulder 19 in the through bore 16 of the metal housing 11; A sealing ring 20 is usually arranged between the shoulder 18 and the shoulder 19. On the connection-side shoulder 21, which is formed between the head 17/1 and the collar 17/2 of the electrical insulating body 17, there is usually also a sealing ring 22; The connection-side area of the metal housing 11 is shaped as a flanged edge 23 over this sealing ring 22. As a result of the described fixing of the electrical insulating body 17 in the housing 11 and additionally by means of the known heat shrinking process (US Pat. No. 2,111,916), the electrical insulating body 17 is held firmly and tightly in the metal housing 11. Instead of using this flanging and heat shrinking process, the electrical insulating body 17 can also be fixed in a sealing manner in the metal housing 11 by cementing or the like.

Der Elektroisolierkörper 17 besitzt in bekannter Weise eine stufenförmige Längsbohrung 24, die in ihren anschlußseitigen Bereich - die sogenannte Kopfbohrung 24/1 - einen größeren Durchmesser hat als der brennraumseitige Bereich - die sogenannte Fußbohrung 24/2; die Fußbohrung 24/2 beginnt etwa im Bereich des Bundansatzes 17/3. Die Fußbohrung 24/2 ist mittels eines angeformten, dünnwandigen Bodens 25 verschlossen, in welchem sich eine aus Edelmetall bestehende bzw. Edelmetall enthaltende Mittelelektrode 26 befindet. Diese Mittelelektrode 26 besteht vorzugsweise aus Platin oder einem Platinmetall, erstreckt sich koaxial zur Längsbohrung 24 des Elektroisolierkörpers 17 und hat einen Durchmesser von 0,3 mm; der maximale Durchmesser einer derartigen metallischen Mittelelektrode beträgt 0,5 mm. Der Boden 25 des Elektroisolierkörpers 17 ist nur 1,5 mm dick, kann im Bedarfsfalle jedoch auch dicker oder dünner gestaltet werden. Die durch diesen Boden 25 hindurchführende Mittelelektrode 26 ist im vorliegenden Beispiel in den Boden 25 spaltfrei eingesintert und ragt anschlußseits 0,5 mm in die Fußbohrung 24/2 des Elektroisolierkörpers 17; je nach Ausführungsform kann der anschlußseitige Endabschnitt der Mittelelektrode 26 aber auch bis zu 1 mm in die Fußbohrung 24/2 hineinragen. Die Mittelelektrode 26, die alternativ auch mittels Kitt, Glas oder ähnlichem im Boden 25 des Elektroisolierkörpers 17 spaltfrei eingebaut sein kann, schließt im vorliegenden Beispiel bündig mit der Stirnfläche 27 des Elektroisolierkörpers 17 ab und steht mit Abstand - der sogenannten Funkenstrecke 28 - dem freien Endabschnitt der Masseelektrode 15 gegenüber. Je nach Anwendungsbereich kann der brennraumseitige Endabschnitt der Mittelelektrode 26 aber auch von anderer Konfiguration sein, er kann z. B. aus der Stirnfläche 27 herausragen oder auch mit einem Kopf versehen sein. Die dargestellte Mittelelektrode 26 mit ihrem Durchmesser von 0,3 mm hat eine Gesamtlänge von 2 mm und wird in bevorzugter Weise als Stift in den Boden 25 des Elektroisolierkörpers 17 eingesintert; je nach der gewählten Dicke des Bodens 25 des Elektroisolierkörpers 17 - bevorzugterweise ist er zwischen 1 und 2,5 mm dic-k - wird auch die Länge der Mittelelektrode 26 ausgewählt, die dann zwischen 1 und 3 mm liegen wird. Die Mittelelektrode 26 kann aber auch als Platin-Suspension in eine in diesem Bereich befindliche vorgeformte Bohrung mit kleinem Durchmesser des noch nicht fertiggesinterten Elektroisolierkörpers 17 eingebracht und dann mit dem Isolierkörper 17 fertiggesintert werden.The electrical insulating body 17 has, in a known manner, a step-shaped longitudinal bore 24 which has a larger diameter in its connection-side area - the so-called head bore 24/1 - than the area on the combustion chamber side - the so-called foot bore 24/2; the foot hole 24/2 begins approximately in the area of the shoulder 17/3. The foot bore 24/2 is closed by means of a molded-on, thin-walled base 25, in which there is a central electrode 26 made of precious metal or containing precious metal. This center electrode 26 is preferably made of platinum or a platinum metal, extends coaxially to the longitudinal bore 24 of the electrical insulating body 17 and has a diameter of 0.3 mm; the maximum diameter of such a metallic center electrode is 0.5 mm. The bottom 25 of the electrical insulating body 17 is only 1.5 mm thick, but can also be made thicker or thinner if necessary. The center electrode 26 passing through this base 25 is sintered into the base 25 without a gap in the present example and protrudes 0.5 mm on the connection side into the foot bore 24/2 of the electrical insulating body 17; depending on the embodiment, the connection-side end section of the center electrode 26 can also protrude up to 1 mm into the foot bore 24/2. The center electrode 26, which can alternatively be installed without a gap in the bottom 25 of the electrical insulating body 17 by means of putty, glass or the like, closes flush with the end face 27 of the electrical insulating body 17 in the present example and stands at a distance - the so-called spark gap 28 - the free end section opposite the ground electrode 15. Depending on the area of application, the end section of the center electrode 26 on the combustion chamber side can also be of a different configuration. B. protrude from the end face 27 or with a head be provided. The center electrode 26 shown with its diameter of 0.3 mm has a total length of 2 mm and is preferably sintered into the base 25 of the electrical insulating body 17 as a pin; depending on the selected thickness of the bottom 25 of the electrical insulating body 17 - preferably it is between 1 and 2.5 mm dic-k - the length of the center electrode 26 is also selected, which will then be between 1 and 3 mm. The center electrode 26 can, however, also be introduced as a platinum suspension in a preformed bore in this area with a small diameter of the electrical insulation body 17 that has not yet been sintered, and can then be finish-sintered with the insulation body 17.

Der anschlußseitige Bereich der Mittelelektrode 26 ist mit einer Vertiefung 29 versehen, welche axial zur Mittelelektrode 26 angeordnet ist und bevorzugt von kegelförmiger oder ähnlicher Form ist. In diese Vertiefung 29, die gemäß dem vorliegenden Beispiel 0,3 mm tief ist, ragt die Anspitzung 30 eines als Kontaktstift dienenden Metallkörpers 31 hinein; dieser Metallkörper 31 mit seiner brennraumseits befindlichen Anspitzung 30 ist bevorzugterweise von kreisförmigem Querschnitt, besteht aus einem relativ billigen Werkstoff, besitzt jedoch eine gute Wärmeleitfähigkeit, eine hohe Korrosionsbeständigkeit (mit ausreichender elektrischer Leitfähigkeit von sich bildenden Zunderschichten), eine hohe Korrosionsfestigkeit zur Vermeidung von Vorfunkenstrecken und einen Wärmeausdehnungskoeffizienten, der dem Keramikmaterial des Elektroisolierkörpers 17 angepaßt ist. Dieser Metallkörper 31 kann beispielsweise aus einer Nickellegierung bestehen, welche unter dem Handelsnamen Vacon 20 bekannt ist (Firma VAC-Hanau), hat einen Durchmesser in der Größenordnung von 1,5 bis 2,5 mm und reicht mit seinem anschlußseitigem Endabschnitt etwas in die Kopfbohrung 24/1 des Elektroisolierkörpers 17. In vorteilhafter Weise ist an den anschlußseitigen Endabschnitt des Metallkörpers 31 ein Kopf 32 angeformt, welcher mit einer zum Anschlußbereich weisenden Verjüngung 33 versehen ist. Der Kopf 32 des Metallkörpers 31 liegt dabei eng in der Fußbohrung 24/2 des Elektroisolierkörpers 17; der brennraumseitige Endabschnitt des Metallkörpers 31 ist zusätzlich in einem Führungsteil 24/2' der Fußbohrung 24/2 fixiert. Der anschlußseitige Endabschnitt des Metallkörpers 31 einschließlich der Verjüngung 33 seines Kopfes 32 sowie der anschlußseits sich anschließende Bereich der Kopfbohrung 24/1 des Isolierkörpers 17 ist mit einer elektrisch-leitfähigen Vergußmasse 34 ausgefüllt; derartige Vergußmassen 34 sind an sich bekannt (z. B. DE-PS 1 206 209, US-PS 2 106 578) und können zusätzlich auch noch (nicht dargestellte) als elektrischer Widerstand wirkende Schichten enthalten (US-PS 3 903 453). Anschlußseits ragt in diese Vergußmasse 34 der brennraumseitige, mit einer Verankerung 35 (z. B. Gewinde oder Kreuzrändelung) versehene Anschlußbolzen 36; dieser Anschlußbolzen 36 besteht aus unlegiertem Stahl, liegt mit einem Bund 37 auf der Stirnseite 38 des Elektroisolierkörpers 17 auf und besitzt ein Anschlußgewinde 39, welches anschlußseits aus dem Elektroisolierkörper 17 herausragt.The connection-side area of the center electrode 26 is provided with a recess 29 which is arranged axially to the center electrode 26 and is preferably of a conical or similar shape. In this recess 29, which according to the present example is 0.3 mm deep, the point 30 of a metal body 31 serving as a contact pin projects; This metal body 31 with its taper 30 located on the combustion chamber side is preferably of circular cross-section, consists of a relatively inexpensive material, but has good thermal conductivity, high corrosion resistance (with sufficient electrical conductivity of scale layers being formed), high corrosion resistance to prevent spark gaps and a coefficient of thermal expansion that is adapted to the ceramic material of the electrical insulating body 17. This metal body 31 can for example consist of a nickel alloy, which is known under the trade name Vacon 20 (company VAC-Hanau), has a diameter of the order of 1.5 to 2.5 mm and extends with its connection-side End portion somewhat in the head bore 24/1 of the electrical insulating body 17. Advantageously, a head 32 is formed on the connection-side end portion of the metal body 31, which is provided with a taper 33 pointing towards the connection area. The head 32 of the metal body 31 lies closely in the foot hole 24/2 of the electrical insulating body 17; the end section of the metal body 31 on the combustion chamber side is additionally fixed in a guide part 24/2 'of the foot bore 24/2. The connection-side end section of the metal body 31 including the taper 33 of its head 32 and the connection-side region of the head bore 24/1 of the insulating body 17 is filled with an electrically conductive casting compound 34; such casting compounds 34 are known per se (e.g. DE-PS 1 206 209, US-PS 2 106 578) and can additionally also contain layers (not shown) acting as electrical resistance (US-PS 3 903 453). On the connection side protrudes into this potting compound 34 the connection bolt 36 provided on the combustion chamber side with an anchoring 35 (eg thread or cross knurling); This connecting bolt 36 is made of unalloyed steel, rests with a collar 37 on the end face 38 of the electrical insulating body 17 and has a connecting thread 39 which protrudes from the electrical insulating body 17 on the connection side.

Infolge des Metallkörpers 31, der je nach Ausführungsform der Zündkerze 10 zwischen 8 und 20mm lang ist, wird nicht nur teueres Material für aus Edelmetall bestehende bzw. Edelmetall enthaltende Mittelelektroden 26 gespart, sondern es wird auch vermieden, daß Vergußmassen 34 in einem Bereich der Zündkerze 10 angeordnet sind, in welchem sie aufgrund von auftretenden hohen Betriebstemperaturen im (nicht dargestellten) Brennraum von Brennkraftmaschinen erschmolzen und infolgedessen unter Umständen nachteilig beeinflußt werden. Die Länge des Metallkörpers 31 wird aus diesem Grunde derart gewählt, daß sich die Vergußmasse 34 bei allen in diesem Bereich vorkommenden Betriebstemperaturen stets sicher unter dem Transformationsbereich der gewählten, elektrisch-leitenden Vergußmasse 34 bleibt. Der Metallkörper 31 hat üblicherweise eine Länge zwischen 8 und 20 mm und üblicherweise einen Durchmesser in der Größenordnung von 1 bis 2,5 mm.As a result of the metal body 31, which, depending on the embodiment of the spark plug 10, is between 8 and 20 mm long, not only is expensive material saved for central electrodes 26 which contain or contain noble metal, but it is also avoided that casting compounds 34 are in an area of the spark plug 10 are arranged in which they occur due to high operating temperatures Melted in the combustion chamber (not shown) of internal combustion engines and, as a result, may be adversely affected. For this reason, the length of the metal body 31 is chosen such that the casting compound 34 always remains safely below the transformation range of the selected, electrically conductive casting compound 34 at all operating temperatures occurring in this area. The metal body 31 usually has a length between 8 and 20 mm and usually a diameter on the order of 1 to 2.5 mm.

Bei einer praktischen Ausführungsform hat der Metallkörper 31 einen Durchmesser von 1,5 mm, einen Kopfdurchmesser von 2 mm und eine Gesamtlänge von 12 mm. Während die Kopfbohrung 24/1 des Elektroisolierkörpers 17 einen Durchmesser von 4,5 mm hat, beträgt der Durchmesser der Fußbohrung 24/2 2,1 mm und der Durchmesser des Führungsteils 24/2' der Fußbohrung 24/2 1,53 mm. Anläßlich der Montage wird der Metallkörper 31 bei Raumtemperatur in die Längsbohrung 24 des Elektroisolierkörpers 17 eingeführt und mit etwa 100 N gegen den anschlußseitigen Endabschnitt der Mittelelektrode 26 gepreßt; dieser Preßdruck reicht aus, um in diesem Bereich der Mittelelektrode 26 die Vertiefung 29 zu formen. Nachdem Einfüllen der zunächst als Granulat vorliegenden Vergußmasse 34 in die Kopfbohrung 24/1 des Elektroisolierkörpers 17, dem nachfolgenden Erwärmen dieser vormontierten Einheit auf etwa 850°C und erneuten Preßvorgängen zwischen 500 und 2500 N auf die Vergußmasse 34 findet zwischen der Anspitzung 30 des Metallkörpers 31 und der Vertiefung 29 der Mittelelektrode 26 eine Diffusionsverschweißung statt, welche einen dauerhaften elektrischen Kontakt zwischen Mittelelektrode 26 und Metallkörper 31 gewährleistet. Während sich die vorstehend beschriebene Baueinheit im aufgeheizten Zustande befindet, wird auch der Anschlußbolzen 36 in die Vergußmasse 34 eingedrückt, in welcher er infolge seiner Verankerungsmittel 35 sicher und mit gutem elektrischen Kontakt gehalten wird.In a practical embodiment, the metal body 31 has a diameter of 1.5 mm, a head diameter of 2 mm and an overall length of 12 mm. While the head bore 24/1 of the electrical insulating body 17 has a diameter of 4.5 mm, the diameter of the foot bore 24/2 is 2.1 mm and the diameter of the guide part 24/2 'of the foot bore 24/2 is 1.53 mm. On the occasion of the assembly, the metal body 31 is inserted into the longitudinal bore 24 of the electrical insulating body 17 at room temperature and pressed against the connection-side end section of the center electrode 26 at approximately 100 N; this pressure is sufficient to form the recess 29 in this area of the central electrode 26. After filling the potting compound 34, which is initially in the form of granules, into the head bore 24/1 of the electrical insulating body 17, the subsequent heating of this preassembled unit to approximately 850 ° C. and renewed pressing operations between 500 and 2500 N on the potting compound 34 take place between the point 30 of the metal body 31 and the recess 29 of the center electrode 26 instead of diffusion welding, which ensures permanent electrical contact between the center electrode 26 and the metal body 31. While the assembly described above is in the heated state, the connecting bolt 36 is also pressed into the casting compound 34, in which it is held securely and with good electrical contact as a result of its anchoring means 35.

Obwohl der Metallkörper 31 nur teilweise in engem Kontakt mit dem Elektroisolierkörper 17 ist, hat sich ergeben, daß die im Bereich der Mittelelektrode 26 entstehende Wärme bei allen Betriebszuständen ausreichend auf den Elektroisolierkörper 17 abgeleitet wird.Although the metal body 31 is only partially in close contact with the electrical insulating body 17, it has been found that the heat generated in the area of the central electrode 26 is sufficiently dissipated to the electrical insulating body 17 in all operating states.

Claims (6)

1. Hochspannungszündkerze, mit einem metallischen, im wesentlichen rohrförmigen Gehäuse, das auf seiner Außenseite Mittel für den Einbau in eine Brennkraftmaschine besitzt, in seiner Durchgangsbohrung einen im wesentlichen rotationssymmetrischen, bevorzugterweise gesinterten Elektroisolierkörper abdichtend umfaßt und an seinem brennraumseitigen Endabschnitt eine Masseelektrode besitzt, welche mit Abstand (Funkenstrecke) einer relativ kurzen, aus Edelmetall bestehenden bzw..Edelmetall enthaltenden Mittelelektrode gegenübersteht, die spaltfrei und abgedichtet im brennraumseitigen Boden der abgestuften Längsbohrung des Elektroisolierkörpers fixiert ist, einen kleineren Durchmesser hat als die sich anschlußseits erstreckenden Stufen der Längsbohrung, innerhalb der Längsbohrung mit einem Metallkörper in direktem Kontakt steht, wobei der anschlußseitige Endabschnitt dieses Metallkörpers in der Längsbohrung mit einer elektrisch-leitenden Vergußmasse abdichtend kontaktiert ist und in dieser Vergußmasse ein Endabschnitt eines elektrisch-leitenden, mit seinem anderen Endabschnitt aus dem anschlußseitigen Ende des Elektroisolierkörpers herausragenden Anschlußbolzen verankert ist, dadurch gekennzeichnet, daß der Metallkörper (31) aus relativ billigem Material besteht, stiftförmig ausgebildet ist, exakt seitlich in der Längsbohrung (24/2, 24/21) des Elektroisolierkörpers (17) geführt ist, brennraumseits eine Anspitzung (30) aufweist, mit welcher er in engem Kontakt mit dem anschlußseitigen Ende der Mittelelektrode (26) steht, und mit seinem anschlußseitigen Endabschnitt bis in denjenigen Bereich der Längsbohrung (24/2, 24/1) des Elektroisolierkörpers (17) hineinragt, welcher während allen in diesem Bereich vorkommenden Betriebstemperaturen stets sicher unter dem Transformationsbereich der elektrisch-leitenden Vergußmasse (34) bleibt.1.High-voltage spark plug, with a metallic, essentially tubular housing, which has on the outside means for installation in an internal combustion engine, in its through-hole sealingly comprises a substantially rotationally symmetrical, preferably sintered electrical insulating body and on its combustion chamber-side end section has a ground electrode, which with The distance (spark gap) from a relatively short center electrode made of or containing precious metal, which is fixed in the combustion chamber-side bottom of the stepped longitudinal bore of the electrical insulating body in a gap-free and sealed manner, has a smaller diameter than the steps of the longitudinal bore extending on the connection side, within the longitudinal bore is in direct contact with a metal body, the connection-side end portion of this metal body being sealed in the longitudinal bore with an electrically conductive casting compound and in this Ve casting compound is an end section of an electrically conductive, is anchored with its other end section from the connection-side end of the electrical insulating body, characterized in that the metal body (31) consists of relatively cheap material, is pin-shaped, exactly laterally in the longitudinal bore (24/2, 24/2 1 ) of the Electrical insulating body (17) is guided, has a point (30) on the combustion chamber side, with which it is in close contact with the connection-side end of the center electrode (26), and with its connection-side end section up to that region of the longitudinal bore (24/2, 24 / 1) of the electrical insulating body (17) protrudes, which always remains safely below the transformation range of the electrically conductive casting compound (34) during all operating temperatures occurring in this area. 2. Hochspannungszündkerze nach Anspruch 1, dadurch gekennzeichnet, daß die Anspitzung (30) des Metallkörpers (31) zumindest teilweise in eine Vertiefung (29) im anschlußseitigen Endabschnitt der Mittelelektrode (26) ragt und bevorzugterweise darin verschweißt ist.2. High-voltage spark plug according to claim 1, characterized in that the point (30) of the metal body (31) at least partially protrudes into a recess (29) in the connection-side end section of the central electrode (26) and is preferably welded therein. 3. Hochspannungszündkerze nach Anspruch 2, dadurch gekennzeichnet, daß der anschlußseitige Endabschnitt der Mittelelektrode (26) bis zu 1 mm, vorzugsweise 0,5 mm in die Längsbohrung (24, 24/2') des Elektroisolierkörpers (17) hineinragt.3. High-voltage spark plug according to claim 2, characterized in that the connection-side end section of the central electrode (26) protrudes up to 1 mm, preferably 0.5 mm, into the longitudinal bore (24, 24/2 ') of the electrical insulating body (17). 4. Hochspannungszündkerze nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Metallkörper (31) in seinem anschlußseitigen Bereich einen Kopf (32) aufweist, der eng in der Längsbohrung (24/2) des Elektroisolierkörpers (17) anliegt und an seinem anschlußseitigen Endabschnitt bevorzugterweise eine Verjüngung (33) besitzt, welche mit der elektrisch-leitenden Vergußmasse (34) in direkter Berührung ist.4. High-voltage spark plug according to one of claims 1 to 3, characterized in that the metal body (31) in its connection-side region has a head (32) which lies closely in the longitudinal bore (24/2) of the electrical insulating body (17) and on it connection end section preferably has a taper (33) which is in direct contact with the electrically conductive casting compound (34). 5. Hochspannungszündkerze nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der stiftförmige Metallkörper (31) bevorzugt eine Länge zwischen 8 und 20 mm und einen Durchmesser in der Größenordnung von 1 bis 2,5 mm hat.5. High-voltage spark plug according to one of claims 1 to 4, characterized in that the pin-shaped metal body (31) preferably has a length between 8 and 20 mm and a diameter in the order of 1 to 2.5 mm. 6. Hochspannungszündkerze nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die kurze Mittelelektrode (26) einen Durchmesser von maximal 0,5 mm und eine bevorzugte Länge zwischen 1 und 3 mm hat.6. High-voltage spark plug according to one of claims 1 to 5, characterized in that the short center electrode (26) has a maximum diameter of 0.5 mm and a preferred length between 1 and 3 mm.
EP83106476A 1982-08-14 1983-07-02 High-tension spark plug Expired EP0101547B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823230362 DE3230362A1 (en) 1982-08-14 1982-08-14 HIGH VOLTAGE SPARK PLUG
DE3230362 1982-08-14

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EP0101547A2 true EP0101547A2 (en) 1984-02-29
EP0101547A3 EP0101547A3 (en) 1984-08-22
EP0101547B1 EP0101547B1 (en) 1987-11-19

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ID=6170941

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EP (1) EP0101547B1 (en)
JP (1) JPS5949181A (en)
BR (1) BR8304350A (en)
DE (2) DE3230362A1 (en)
ES (1) ES8405206A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996007226A1 (en) * 1994-09-01 1996-03-07 Robert Bosch Gmbh Spark plug for an internal combustion engine
EP0845167B1 (en) * 1996-06-15 2003-01-15 Robert Bosch Gmbh Spark plug for internal combustion engine
DE10156949A1 (en) * 2001-11-20 2003-06-05 Bosch Gmbh Robert Spark plug for combustion engine has electrode connected to ignition cable via bolt, isolated from housing and with diameter essentially less than or equal to 2 mm. over entire length
US6819030B2 (en) 2002-04-09 2004-11-16 Robert Bosch Gmbh Spark plug
US7443089B2 (en) 2006-06-16 2008-10-28 Federal Mogul World Wide, Inc. Spark plug with tapered fired-in suppressor seal
CN107790862A (en) * 2017-10-20 2018-03-13 株洲湘火炬火花塞有限责任公司 Spark-plug side electrode welding fusing amount control method and its control system

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6161390A (en) * 1984-08-30 1986-03-29 日本特殊陶業株式会社 Ignition plug
EP1116308B1 (en) * 1999-07-29 2002-12-18 Robert Bosch Gmbh Spark plug for an internal combustion engine
DE10329269B4 (en) * 2003-06-30 2005-12-29 Robert Bosch Gmbh Spark plug with at least two center electrodes
DE102010004345B4 (en) * 2010-01-11 2018-02-22 Viessmann Werke Gmbh & Co Kg Electrode for flame monitoring on a heating burner

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US2072732A (en) * 1935-08-28 1937-03-02 Gen Electric Spark plug
GB801685A (en) * 1955-03-26 1958-09-17 Lodge Plugs Ltd Improvements in or relating to sparking plugs
US3509403A (en) * 1967-07-24 1970-04-28 Cecil J Krow Spark plug having a reversible inner electrode
DE2308915A1 (en) * 1973-02-23 1974-09-05 Otto Pickl SPARK PLUG FOR OTTO ENGINES
GB2054738A (en) * 1979-07-31 1981-02-18 Meadowbank Investments Ltd Improvements in Sparking Plugs

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DE199601C (en) *
US1361328A (en) * 1919-05-28 1920-12-07 Chauncey R Watson Spark-plug
US2072732A (en) * 1935-08-28 1937-03-02 Gen Electric Spark plug
GB801685A (en) * 1955-03-26 1958-09-17 Lodge Plugs Ltd Improvements in or relating to sparking plugs
US3509403A (en) * 1967-07-24 1970-04-28 Cecil J Krow Spark plug having a reversible inner electrode
DE2308915A1 (en) * 1973-02-23 1974-09-05 Otto Pickl SPARK PLUG FOR OTTO ENGINES
GB2054738A (en) * 1979-07-31 1981-02-18 Meadowbank Investments Ltd Improvements in Sparking Plugs

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996007226A1 (en) * 1994-09-01 1996-03-07 Robert Bosch Gmbh Spark plug for an internal combustion engine
EP0845167B1 (en) * 1996-06-15 2003-01-15 Robert Bosch Gmbh Spark plug for internal combustion engine
DE10156949A1 (en) * 2001-11-20 2003-06-05 Bosch Gmbh Robert Spark plug for combustion engine has electrode connected to ignition cable via bolt, isolated from housing and with diameter essentially less than or equal to 2 mm. over entire length
DE10156949B4 (en) * 2001-11-20 2004-03-04 Robert Bosch Gmbh spark plug
US6819030B2 (en) 2002-04-09 2004-11-16 Robert Bosch Gmbh Spark plug
US7443089B2 (en) 2006-06-16 2008-10-28 Federal Mogul World Wide, Inc. Spark plug with tapered fired-in suppressor seal
CN107790862A (en) * 2017-10-20 2018-03-13 株洲湘火炬火花塞有限责任公司 Spark-plug side electrode welding fusing amount control method and its control system

Also Published As

Publication number Publication date
EP0101547B1 (en) 1987-11-19
EP0101547A3 (en) 1984-08-22
BR8304350A (en) 1984-03-20
JPS5949181A (en) 1984-03-21
ES524936A0 (en) 1984-05-16
DE3374633D1 (en) 1987-12-23
JPH0544151B2 (en) 1993-07-05
DE3230362A1 (en) 1984-02-16
ES8405206A1 (en) 1984-05-16

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