EP3143332A1 - Preheater electrode with insulating seal - Google Patents

Preheater electrode with insulating seal

Info

Publication number
EP3143332A1
EP3143332A1 EP15718895.4A EP15718895A EP3143332A1 EP 3143332 A1 EP3143332 A1 EP 3143332A1 EP 15718895 A EP15718895 A EP 15718895A EP 3143332 A1 EP3143332 A1 EP 3143332A1
Authority
EP
European Patent Office
Prior art keywords
central electrode
sleeve
seal
bore
connector
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Withdrawn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
EP15718895.4A
Other languages
German (de)
French (fr)
Inventor
Jean-Marc Couffignal
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP3143332A1 publication Critical patent/EP3143332A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23Q—IGNITION; EXTINGUISHING-DEVICES
    • F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
    • F23Q7/001—Glowing plugs for internal-combustion engines

Definitions

  • the present invention relates to a preheating spark plug with either ceramic or metal tube cartridge
  • a preheating spark plug with either ceramic or metal tube cartridge comprising a tubular metal body provided with a thread for screwing into the engine cylinder head and carrying the heating element in the cartridge, the body being traversed by a central electrode connected to a terminal of the heating element whose other terminal is connected to the body making the connection to ground, the body carrying at its other end a primary connector receiving the connector of the manufacturer.
  • This primary connector installed on the electrode is connected to it by being isolated from the body by an electrical insulation ring.
  • the invention also relates to a method of manufacturing such a glow plug.
  • the glow plug 200 is composed at the front, not shown, of a body provided with a heated front end, for example ceramic, containing a heating electric filament of which a connection is connected to the tubular body 210, conductive, him -even connected to the mass by its screwing (thread 212) in the motor and whose other connection is connected to a central electrode 220 through the bore 211 of the tubular body 210 while being isolated therefrom, to be connected its other end to the primary connector 240 itself receiving the connector of the manufacturer to thereby supply the heating element.
  • the rear end of the central electrode 220 is provided with a knurled portion 221 and is housed in the blind hole 241 of the primary connector 240 to be fixed by the crimping 250.
  • the rear end 213, which externally forms a tool socket for screwing the spark plug, has, at the outlet of the bore 21 1, a bearing cone 214 and a countersink 215 for receiving a gasket. sealing 230 and an insulating washer 235 both engaged on the central electrode 220 and thus separating it from the contact with the body 210 when these seals 230, 235 are compressed both against each other and against the bearing cone 214 and countersink 215.
  • the primary connector 240 engaged on the end of the central electrode 220 is pressed towards the rear portion 213 of the body 210 is crimped 250 ( Figure 1B) against the knurling 221 .
  • the very large temperature variations experienced by the glow plug 200 cause significant length variations of the components such as the central electrode 220 and the tubular body 210. These variations in the length of the central electrode 220 are much greater than those of the tubular body 210.
  • the insulating washer 235 does not remain in contact with the countersink 215 of the tubular body 210 and the seal between the inside of the bore 21 1 and the external environment may be broken.
  • the seal 230 which is a flexible, toric seal is interposed between the tubular body 210 and the insulating washer 235.
  • the seal 230 is oversized at rest and is set permanent compression by the insulating washer 235 and the connector 240.
  • the connector 240 is held in position on the central electrode 220 by its crimping 250 on the knurling 221.
  • the seal being provided by the elasticity. This sealing is done on the three areas of contact of the seal with the support cone 214, the central electrode 220 and the front surface of the insulating washer 235.
  • the seal undergoes an extension of its diameter during its passage on the knurling 221 of the central electrode 220.
  • the outer diameter of the knurling 221 is indeed greater to the diameter of the smooth portion of the central electrode 220. This passage is made possible by the elasticity of the O-ring 230. Then put in compression by the thrust exerted by the end with the support flange 242 of the connector 240 on the isolation washer 235 which rests on the seal 230. This compression of the components is ensured permanently thanks to the crimping 250 of the connector 240 on the knurling 221 of the central electrode 220.
  • the present invention aims to simplify the manufacture of the glow plug and improve its reliability and efficiency by reducing the number of components.
  • the subject of the present invention is a glow plug of the type defined above, characterized in that the rear end of the body terminates in a bearing surface into which the bore opens, the central electrode comprises a knurling whose outer diameter is smaller than the diameter of the smooth portion of the central electrode, the seal is formed of a sleeve having a collar, the sleeve has a thickness greater than the size of the gap between the smooth surface of the the central electrode and the bore, this sleeve being inserted by force into the gap and the flange coming to bear against the bearing face of the rear part and the bearing flange of the connector, and the internal diameter of the sleeve is greater than the outside diameter of the knurling.
  • the glow plug according to the invention achieves the sealing of the cavity through the seal whose sleeve which seals despite the relative movements between the body of the candle and the central electrode under the effect of temperature changes.
  • the realization of the candle is simple since it sets up a single seal.
  • the bearing surface of the rear end of the body comprises a counterbore receiving the collar of the seal.
  • the collar of the seal can bear directly against the bearing surface of the rear part but preferably, this bearing surface comprises a counterbore so that a portion of the collar is locked in the counterbore leaving a portion of the thickness of the collar to protrude to allow support of the flange of the connector which ensures the tightening of the assembly.
  • the seal is made of polyamide, in particular of PA6 / 6 copolymer of caprolactam PA6.
  • This seal has the advantage of withstanding the temperature variations and aggressive agents to which it may be exposed during operation of the engine.
  • Figure 1A is an axial sectional view of the rear end of a glow plug according to the invention after crimping.
  • FIG. 2A is a view in axial section analogous to that of FIG. 1A but with the connector and the joint disassembled,
  • FIG. 3A shows an axial sectional view showing the assembly of the rear end of the candle before crimping
  • Figures 1B, 2B, 3B are sectional views of the rear end of a known glow plug, presented under the same conditions as the glow plug of the invention and highlighting the differences between the two candles.
  • the drawings show only the rear end of the glow plug according to the invention (and also that of the known glow plug), that is to say the portion of the electrode provided with the primary connector, the front end, with ceramic cartridge, heating is not shown.
  • the glow plug 1 of the invention consists of a tubular body 10 whose not shown front end is provided with a ceramic heating cartridge or metal tube housing a resistant filament, heating. This filament is connected at one end to the tubular body 10 forming a conductor for connection with the ground of the vehicle electrical circuit and its other end is connected to a central electrode 20 passing through the bore 11 of the tubular body 10 to receive at its end.
  • a primary connector 40 with interposition of a seal 30 providing both sealing and electrical insulation between the central electrode 20 assembled to the connector 40 and the body 10.
  • the conductive metal body has, in addition to its bore 11 which passes through it end-to-end, a thread 12 for screwing the spark plug into the engine cylinder head.
  • the rear of the body 10 terminates in a rear portion 13 forming a tool socket for screwing the candle.
  • This portion 13 internally has a smooth surface formed by the end 14 of the bore and the rear face 131 of the portion 13 to a recess 15 to receive the seal 30 in support.
  • the central electrode 20, of which only the rear part is represented, is constituted by a smooth, cylindrical rod of diameter D0 which terminates at the rear end by a knurling 21 whose diameter D i is less than or at most equal to the diameter Do the smooth part.
  • the seal 30 consists of a sleeve 31 whose outer diameter D2 is slightly greater than the inner diameter D3 of the bore 11 and the inner diameter D4 is substantially equal to the diameter D0 of the central electrode 20.
  • the sleeve 31 is continued by a flange 32 made in one piece with the sleeve 31.
  • the sleeve 31 is housed in the gap between the central electrode 20 and the end 14 of the bore by a tight fitting, the collar 32 coming into part in the counterbore 15. The assembly is clamped by the connector 40.
  • the connector 40 is a solid piece provided with a piercing terminal 41 to receive the end of the central electrode 20 including its knurled portion 21.
  • the connector 40 has a support flange 42 followed by a stop flange 43 defining the surface 44 receiving the connector of the manufacturer.
  • the assembly ends by crimping 50 of the portion of the connector 40 between the two flanges 42, 43 on the knurled end 21 of the central electrode 20.
  • the sealing of the interior of the spark plug is achieved by the tight contact of the sleeve 31 and its permanent compression between the smooth surface of the central electrode 20 and the bore 1 1 in its part 14.
  • the thickness of the wall of the sleeve 31, that is to say greater than the dimension of the gap between the bore 1 1 in its portion 14 and the smooth wall of the central electrode 20 is (D3-Do) / 2.
  • the internal diameter D 4 is equal to the diameter C 0 of the central electrode 20 so that the sleeve 31 is not likely to be blocked or damaged by the knurling 21 whose diameter Di is smaller than the diameter C d central electrode 20.
  • the seal 30 is preferably obtained by injection of composite plastic under heat and pressure, polyamide PA6 or PA66.
  • the seal is obtained by the force introduction of the sleeve 31 between the two surfaces defining the circular gap in the central electrode.
  • the reduction in the thickness of the sleeve 31 resulting from its forced insertion into the gap applies the sleeve 31 to pressure evenly against the surface of the bore 1 1 and that of the central electrode 20. This pressure remains constant and ensures the seal between the cavity of the tubular body and the environment.
  • Figure 1A shows the glow plug in the finished state after crimping.
  • FIG. 2A shows the first step of mounting the rear end of the glow plug 1, the front end being already assembled, that is to say the heating cartridge being fixed to the body 10 and to the front end of the central electrode 20.
  • the unassembled sectional view of FIG. 2A makes it possible to see more precisely the shape of the different elements at their junctions.
  • Figure 3A shows the assembly of the rear end of the glow plug 1 before crimping and after crimping the glow plug 1 is in the completed state, shown in Figure 1A.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Resistance Heating (AREA)
  • Spark Plugs (AREA)

Abstract

The invention relates to a preheater plug of which the rear end (13) of the body (10) terminates in a bearing surface (131) into which the bore (11) opens. The central electrode (20) comprises a knurled portion (21) of which the external diameter (D1) is smaller than the diameter (D0) of the smooth portion of the central electrode (20). The seal (30) is formed from a sleeve (31) comprising a collar (32). The thickness (e) of the sleeve (31) is greater than the dimension of the gap (i) between the smooth surface of the central electrode (20) and the bore (11), the sleeve being inserted by force into the gap (i).The internal diameter (D4) of the sleeve (31) is larger than the external diameter (D1) of the knurled portion (21).

Description

Electrode de préchauffage à joint d'isolation  Insulating gas preheating electrode
Domaine de l'invention Field of the invention
La présente invention se rapporte à une bougie de pré- chauffage à cartouche indifféremment en céramique ou à tube métallique comprenant un corps métallique tubulaire muni d'un filetage pour se visser dans la culasse du moteur et portant l'élément chauffant dans la cartouche, le corps étant traversé par une électrode centrale reliée à une borne de l'élément chauffant dont l'autre borne est reliée au corps faisant la liaison à la masse, le corps portant à son autre extrémité un connecteur primaire recevant le connecteur du constructeur. Ce connecteur primaire installé sur l'électrode est relié à celle-ci en étant isolé du corps par une bague d'isolation électrique.  The present invention relates to a preheating spark plug with either ceramic or metal tube cartridge comprising a tubular metal body provided with a thread for screwing into the engine cylinder head and carrying the heating element in the cartridge, the body being traversed by a central electrode connected to a terminal of the heating element whose other terminal is connected to the body making the connection to ground, the body carrying at its other end a primary connector receiving the connector of the manufacturer. This primary connector installed on the electrode is connected to it by being isolated from the body by an electrical insulation ring.
L'invention se rapporte également à un procédé de fabri- cation d'une telle bougie de préchauffage.  The invention also relates to a method of manufacturing such a glow plug.
Etat de la technique State of the art
Selon l'état de la technique, on connaît différentes bougies de préchauffage. L'une de ces bougies 200 est représentée en coupe des figures 1B, 2B, 3B pour la partie arrière, celle servant à la fixation du corps 210 de la bougie dans la chambre du moteur par le filetage 212 et la partie qui en dépasse pour recevoir le connecteur primaire 240 qui recevra le connecteur du constructeur. Ce connecteur primaire 240 est en général propre au constructeur alors que les autres parties de la bougie de préchauffage 200 sont les mêmes, quel que soit le construc- teur automobile qui installe la bougie de préchauffage 200.  According to the state of the art, various glow plugs are known. One of these candles 200 is shown in cross-section of FIGS. 1B, 2B, 3B for the rear part, that serving for fastening the body 210 of the spark plug in the engine chamber by the threading 212 and the part which exceeds it for receive the primary connector 240 which will receive the connector of the manufacturer. This primary connector 240 is in general manufacturer-specific whereas the other parts of the glow plug 200 are the same, regardless of the automobile manufacturer who installs the glow plug 200.
La bougie de préchauffage 200 se compose à l'avant, non représenté, d'un corps muni d'une extrémité avant chauffante, par exemple en céramique, contenant un filament électrique chauffant dont une connexion est reliée au corps tubulaire 210, conducteur, lui-même relié à la masse par son vissage (filetage 212) dans le moteur et dont l'autre connexion est reliée à une électrode centrale 220 traversant l'alésage 211 du corps tubulaire 210 tout en étant isolée de celui-ci, pour être reliée par son autre extrémité au connecteur primaire 240 recevant lui-même le connecteur du constructeur pour alimenter ainsi l'élément chauffant. L'extrémité arrière de l'électrode centrale 220 est munie d'une partie moletée 221 et se loge dans le perçage borgne 241 du connecteur primaire 240 pour y être fixée par le sertissage 250. The glow plug 200 is composed at the front, not shown, of a body provided with a heated front end, for example ceramic, containing a heating electric filament of which a connection is connected to the tubular body 210, conductive, him -even connected to the mass by its screwing (thread 212) in the motor and whose other connection is connected to a central electrode 220 through the bore 211 of the tubular body 210 while being isolated therefrom, to be connected its other end to the primary connector 240 itself receiving the connector of the manufacturer to thereby supply the heating element. The rear end of the central electrode 220 is provided with a knurled portion 221 and is housed in the blind hole 241 of the primary connector 240 to be fixed by the crimping 250.
Selon la figure 2B, l'extrémité arrière 213 qui forme extérieurement une prise d'outil pour le vissage de la bougie, comporte au débouché de l'alésage 21 1, un cône d'appui 214 et un lamage 215 pour recevoir un joint d'étanchéité 230 et une rondelle d'isolation 235 engagés tous deux sur l'électrode centrale 220 et la séparant ainsi du contact avec le corps 210 lorsque ces joints 230, 235 sont comprimés à la fois l'un contre l'autre et contre le cône d'appui 214 et le lamage 215. Lorsque le connecteur primaire 240 engagé sur l'extrémité de l'électrode centrale 220 est pressé en direction de la partie arrière 213 du corps 210 il est serti 250 (figure 1B) contre le moletage 221.  According to FIG. 2B, the rear end 213, which externally forms a tool socket for screwing the spark plug, has, at the outlet of the bore 21 1, a bearing cone 214 and a countersink 215 for receiving a gasket. sealing 230 and an insulating washer 235 both engaged on the central electrode 220 and thus separating it from the contact with the body 210 when these seals 230, 235 are compressed both against each other and against the bearing cone 214 and countersink 215. When the primary connector 240 engaged on the end of the central electrode 220 is pressed towards the rear portion 213 of the body 210 is crimped 250 (Figure 1B) against the knurling 221 .
Les très importantes variations de température que subit la bougie de préchauffage 200 entraînent des variations de longueur importantes des composants tels que l'électrode centrale 220 et le corps tubulaire 210. Ces variations de longueur de l'électrode centrale 220 sont beaucoup plus importantes que celles du corps tubulaire 210. La rondelle d'isolation 235 ne reste plus en contact avec le lamage 215 du corps tubulaire 210 et l'étanchéité entre l'intérieur de l'alésage 21 1 et l'environnement extérieur risque d'être rompue. Pour éviter cet inconvénient de défaut d'étanchéité, le joint 230 qui est un joint souple, torique est interposé entre le corps tubulaire 210 et la rondelle d'isolation 235. Le joint d'étanchéité 230 est surdimensionné au repos et il est mis en compression permanente par la rondelle d'isolation 235 et le connecteur 240. Pour maintenir cette compression permanente du joint 230, le connecteur 240 est maintenu en position sur l'électrode centrale 220 par son sertissage 250 sur le moletage 221. Or, lors des variations de l'ensemble constitué par l'électrode centrale 220, la rondelle d'isolation 235 et le connecteur 240, l'étanchéité étant assurée par l'élasticité. Cette étanchéité se fait sur les trois zones de contact du joint avec le cône d'appui 214, l'électrode centrale 220 et la surface avant de la rondelle d'isolation 235. Pour cela, au moment de l'assemblage du joint torique 230 sur l'électrode centrale 220, le joint subit une extension de son diamètre lors de son passage sur le moletage 221 de l'électrode cen- traie 220. Le diamètre extérieur du moletage 221 est en effet supérieur au diamètre de la partie lisse de l'électrode centrale 220. Ce passage est rendu possible grâce à l'élasticité du joint torique 230. Ensuite mis en compression par la poussée exercée par l'extrémité avec la collerette d'appui 242 du connecteur 240 sur la rondelle d'isolation 235 qui s'appuie sur le joint d'étanchéité 230. Cette compression des composants est assurée de manière permanente grâce au sertissage 250 du connecteur 240 sur le moletage 221 de l'électrode centrale 220. The very large temperature variations experienced by the glow plug 200 cause significant length variations of the components such as the central electrode 220 and the tubular body 210. These variations in the length of the central electrode 220 are much greater than those of the tubular body 210. The insulating washer 235 does not remain in contact with the countersink 215 of the tubular body 210 and the seal between the inside of the bore 21 1 and the external environment may be broken. To avoid this inconvenience of leakage, the seal 230 which is a flexible, toric seal is interposed between the tubular body 210 and the insulating washer 235. The seal 230 is oversized at rest and is set permanent compression by the insulating washer 235 and the connector 240. To maintain this permanent compression of the seal 230, the connector 240 is held in position on the central electrode 220 by its crimping 250 on the knurling 221. However, during variations of the assembly consisting of the central electrode 220, the insulating washer 235 and the connector 240, the seal being provided by the elasticity. This sealing is done on the three areas of contact of the seal with the support cone 214, the central electrode 220 and the front surface of the insulating washer 235. For this, at the time of assembly of the O-ring 230 on the central electrode 220, the seal undergoes an extension of its diameter during its passage on the knurling 221 of the central electrode 220. The outer diameter of the knurling 221 is indeed greater to the diameter of the smooth portion of the central electrode 220. This passage is made possible by the elasticity of the O-ring 230. Then put in compression by the thrust exerted by the end with the support flange 242 of the connector 240 on the isolation washer 235 which rests on the seal 230. This compression of the components is ensured permanently thanks to the crimping 250 of the connector 240 on the knurling 221 of the central electrode 220.
Or, ces différents composants et ce mode d'assemblage représentent un coût important de la fabrication de la bougie de pré- chauffage tant à cause du nombre de composants que de l'opération d'assemblage.  However, these various components and this method of assembly represent a significant cost of the manufacture of the preheating spark plug both because of the number of components that the assembly operation.
But de l'invention Purpose of the invention
La présente invention a pour but de simplifier la fabrication de la bougie de préchauffage et d'améliorer sa fiabilité et son efficacité en réduisant le nombre de composants.  The present invention aims to simplify the manufacture of the glow plug and improve its reliability and efficiency by reducing the number of components.
Exposé et avantages de l'invention Description and advantages of the invention
A cet effet, la présente invention a pour objet une bougie de préchauffage du type défini ci-dessus caractérisée en ce que l'extrémité arrière du corps se termine par une surface d'appui dans laquelle débouche l'alésage, l'électrode centrale comporte un moletage dont le diamètre extérieur est inférieur au diamètre de la partie lisse de l'électrode centrale, le joint est formé d'un manchon comportant une collerette, le manchon a une épaisseur supérieure à la dimension de l'intervalle entre la surface lisse de l'électrode centrale et l'alésage, ce manchon étant inséré de force dans l'intervalle et la collerette venant s'appuyer contre la face d'appui de la partie arrière et la collerette d'appui du connecteur, et le diamètre intérieur du manchon est supérieur au diamètre extérieur du moletage.  For this purpose, the subject of the present invention is a glow plug of the type defined above, characterized in that the rear end of the body terminates in a bearing surface into which the bore opens, the central electrode comprises a knurling whose outer diameter is smaller than the diameter of the smooth portion of the central electrode, the seal is formed of a sleeve having a collar, the sleeve has a thickness greater than the size of the gap between the smooth surface of the the central electrode and the bore, this sleeve being inserted by force into the gap and the flange coming to bear against the bearing face of the rear part and the bearing flange of the connector, and the internal diameter of the sleeve is greater than the outside diameter of the knurling.
La bougie de préchauffage selon l'invention réalise l'étanchéité de la cavité grâce au joint dont le manchon qui réalise l'étanchéité malgré les mouvements relatifs entre le corps de la bougie et l'électrode centrale sous l'effet des variations de température. La réalisation de la bougie est simple puisqu'on met en place un seul joint. Suivant une autre caractéristique avantageuse, la surface d'appui de l'extrémité arrière du corps comporte un lamage recevant la collerette du joint. The glow plug according to the invention achieves the sealing of the cavity through the seal whose sleeve which seals despite the relative movements between the body of the candle and the central electrode under the effect of temperature changes. The realization of the candle is simple since it sets up a single seal. According to another advantageous characteristic, the bearing surface of the rear end of the body comprises a counterbore receiving the collar of the seal.
Dans le cas général, la collerette du joint peut s'appuyer directement contre la surface d'appui de la partie arrière mais de manière préférentielle, cette surface d'appui comporte un lamage pour qu'une partie de la collerette soit bloquée dans le lamage en laissant dépasser une partie de l'épaisseur de la collerette pour permettre l'appui de la collerette du connecteur qui assure le serrage du montage.  In the general case, the collar of the seal can bear directly against the bearing surface of the rear part but preferably, this bearing surface comprises a counterbore so that a portion of the collar is locked in the counterbore leaving a portion of the thickness of the collar to protrude to allow support of the flange of the connector which ensures the tightening of the assembly.
Suivant une autre caractéristique, le joint est en polyamide, notamment en copolymère PA6/6 de caprolactame PA6. Ce joint a l'avantage de bien résister aux variations de température et aux agents agressifs auxquels il peut être exposé pendant le fonctionnement du moteur.  According to another characteristic, the seal is made of polyamide, in particular of PA6 / 6 copolymer of caprolactam PA6. This seal has the advantage of withstanding the temperature variations and aggressive agents to which it may be exposed during operation of the engine.
Dessins drawings
La présente invention sera décrite ci-après de manière plus détaillée à l'aide d'une bougie de préchauffage selon l'invention représenté dans les dessins annexés et d'une bougie de préchauffage connue présentée de façon analogue à titre de comparaison :  The present invention will be described below in more detail using a glow plug according to the invention shown in the accompanying drawings and a known glow plug presented analogously for comparison:
la figure 1A est une vue en coupe axiale de l'extrémité arrière d'une bougie de préchauffage selon l'invention après sertissage.  Figure 1A is an axial sectional view of the rear end of a glow plug according to the invention after crimping.
la figure 2A est une vue en coupe axiale analogue à celle de la figure 1A mais avec le connecteur et le joint démontés,  FIG. 2A is a view in axial section analogous to that of FIG. 1A but with the connector and the joint disassembled,
la figure 3A montre une vue en coupe axiale montrant l'assemblage de l'extrémité arrière de la bougie avant le sertissage,  FIG. 3A shows an axial sectional view showing the assembly of the rear end of the candle before crimping,
les figures 1B, 2B, 3B sont des vues en coupe de l'extrémité arrière d'une bougie de préchauffage connue, présentée dans les mêmes conditions que la bougie de préchauffage de l'invention et mettant en évidence les différences entre les deux bougies.  Figures 1B, 2B, 3B are sectional views of the rear end of a known glow plug, presented under the same conditions as the glow plug of the invention and highlighting the differences between the two candles.
Description d'un mode de réalisation de l'invention Description of an embodiment of the invention
Par convention, les dessins ne montrent que l'extrémité arrière de la bougie de préchauffage selon l'invention (et celle aussi de la bougie de préchauffage connue) c'est-à-dire la partie de l'électrode munie du connecteur primaire, l'extrémité avant, avec de la cartouche en céramique, chauffante n'étant pas représentée. Selon la figure 1A, la bougie de préchauffage 1 de l'invention se compose d'un corps tubulaire 10 dont l'extrémité avant non représentée est munie d'une cartouche chauffante en céramique ou à tube métallique logeant un filament résistant, chauffant. Ce filament est relié par une extrémité au corps tubulaire 10 formant conducteur pour la liaison avec la masse du circuit électrique du véhicule et son autre extrémité est reliée à une électrode centrale 20 traversant l'alésage 1 1 du corps tubulaire 10 pour recevoir à son extrémité arrière, un connecteur primaire 40 avec interposition d'un joint 30 assurant à la fois l'étanchéité et l'isolation électrique entre l'électrode centrale 20 assemblée au connecteur 40 et le corps 10. By convention, the drawings show only the rear end of the glow plug according to the invention (and also that of the known glow plug), that is to say the portion of the electrode provided with the primary connector, the front end, with ceramic cartridge, heating is not shown. According to Figure 1A, the glow plug 1 of the invention consists of a tubular body 10 whose not shown front end is provided with a ceramic heating cartridge or metal tube housing a resistant filament, heating. This filament is connected at one end to the tubular body 10 forming a conductor for connection with the ground of the vehicle electrical circuit and its other end is connected to a central electrode 20 passing through the bore 11 of the tubular body 10 to receive at its end. rear, a primary connector 40 with interposition of a seal 30 providing both sealing and electrical insulation between the central electrode 20 assembled to the connector 40 and the body 10.
De façon plus détaillée, selon la figure 2A le corps 10 métallique, conducteur, a, outre son alésage 1 1 qui le traverse de bout en bout, un filetage 12 pour visser la bougie dans la culasse du moteur. L'arrière du corps 10 se termine par une partie arrière 13 formant une prise d'outil pour le vissage de la bougie. Cette partie 13 présente intérieurement une surface lisse constituée par l'extrémité 14 de l'alésage et la face arrière 131 de la partie 13 à un lamage 15 pour recevoir le joint 30 en appui.  In more detail, according to FIG. 2A, the conductive metal body has, in addition to its bore 11 which passes through it end-to-end, a thread 12 for screwing the spark plug into the engine cylinder head. The rear of the body 10 terminates in a rear portion 13 forming a tool socket for screwing the candle. This portion 13 internally has a smooth surface formed by the end 14 of the bore and the rear face 131 of the portion 13 to a recess 15 to receive the seal 30 in support.
L'électrode centrale 20 dont seule la partie arrière est représentée, est constituée par une tige lisse, cylindrique, de diamètre D0 qui se termine à l'extrémité arrière par un moletage 21 dont le diamètre D i est inférieur ou au plus égal au diamètre Do de la partie lisse.  The central electrode 20, of which only the rear part is represented, is constituted by a smooth, cylindrical rod of diameter D0 which terminates at the rear end by a knurling 21 whose diameter D i is less than or at most equal to the diameter Do the smooth part.
Le joint 30 se compose d'un manchon 31 dont le dia- mètre extérieur D2 est légèrement supérieur au diamètre intérieur D3 de l'alésage 11 et le diamètre intérieur D4 est sensiblement égal au diamètre D0 de l'électrode centrale 20. Le manchon 31 se poursuit par une collerette 32 réalisée en une seule pièce avec le manchon 31. Le manchon 31 se loge dans l'intervalle entre l'électrode centrale 20 et l'extrémité 14 de l'alésage par un montage serré, la collerette 32 venant en partie dans le lamage 15. L'ensemble est serré par le connecteur 40.  The seal 30 consists of a sleeve 31 whose outer diameter D2 is slightly greater than the inner diameter D3 of the bore 11 and the inner diameter D4 is substantially equal to the diameter D0 of the central electrode 20. The sleeve 31 is continued by a flange 32 made in one piece with the sleeve 31. The sleeve 31 is housed in the gap between the central electrode 20 and the end 14 of the bore by a tight fitting, the collar 32 coming into part in the counterbore 15. The assembly is clamped by the connector 40.
Le connecteur 40 est une pièce pleine munie d'un perçage borne 41 pour recevoir l'extrémité de l'électrode centrale 20 notamment sa partie moletée 21. A l'avant, le connecteur 40 a une collerette d'appui 42 suivi d'une collerette de butée 43 délimitant la surface 44 recevant le connecteur du constructeur. The connector 40 is a solid piece provided with a piercing terminal 41 to receive the end of the central electrode 20 including its knurled portion 21. At the front, the connector 40 has a support flange 42 followed by a stop flange 43 defining the surface 44 receiving the connector of the manufacturer.
L'assemblage se termine par le sertissage 50 de la partie du connecteur 40 comprise entre les deux collerettes 42, 43 sur l'extrémité moletée 21 de l'électrode centrale 20. The assembly ends by crimping 50 of the portion of the connector 40 between the two flanges 42, 43 on the knurled end 21 of the central electrode 20.
L'étanchéité de l'intérieur de la bougie est réalisée par le contact serré du manchon 31 et sa compression permanente entre la surface lisse de l'électrode centrale 20 et de l'alésage 1 1 en sa partie 14. Pour cela, l'épaisseur de la paroi du manchon 31 c'est-à-dire est supérieure à la dimension de l'intervalle entre l'alésage 1 1 en sa partie 14 et la paroi lisse de l'électrode centrale 20 soit (D3-Do) /2. De plus le diamètre intérieur D4, est égal au diamètre Do de l'électrode centrale 20 de sorte que le manchon 31 ne risque pas d'être bloqué ou abîmé par le moletage 2 1 dont le diamètre Di est inférieur au diamètre Do de l'électrode centrale 20. Le joint 30 est de préférence obtenu par injection de matière plastique composites à chaud et sous pression, de polyamide PA6 ou PA66. The sealing of the interior of the spark plug is achieved by the tight contact of the sleeve 31 and its permanent compression between the smooth surface of the central electrode 20 and the bore 1 1 in its part 14. For this, the thickness of the wall of the sleeve 31, that is to say greater than the dimension of the gap between the bore 1 1 in its portion 14 and the smooth wall of the central electrode 20 is (D3-Do) / 2. In addition, the internal diameter D 4 is equal to the diameter C 0 of the central electrode 20 so that the sleeve 31 is not likely to be blocked or damaged by the knurling 21 whose diameter Di is smaller than the diameter C d central electrode 20. The seal 30 is preferably obtained by injection of composite plastic under heat and pressure, polyamide PA6 or PA66.
L'étanchéité est obtenue par l'introduction en force du manchon 31 entre les deux surfaces délimitant l'intervalle circulaire dans l'électrode centrale. La diminution de l'épaisseur du manchon 31 résultant de son introduction forcée dans l'intervalle applique le manchon 3 1 à pression égale contre la surface de l'alésage 1 1 et celle de l'électrode centrale 20. Cette pression reste constante et assure l'étanchéité entre la cavité du corps tubulaire et de l'environnement.  The seal is obtained by the force introduction of the sleeve 31 between the two surfaces defining the circular gap in the central electrode. The reduction in the thickness of the sleeve 31 resulting from its forced insertion into the gap applies the sleeve 31 to pressure evenly against the surface of the bore 1 1 and that of the central electrode 20. This pressure remains constant and ensures the seal between the cavity of the tubular body and the environment.
Comme la surface intérieure du manchon 3 1 ne peut pas être abimée par son passage sur le moletage 21 , il n'y a pas de risque de défaut d'étanchéité au niveau de la surface intérieure du manchon 31 appliquée contre la partie lisse de l'électrode centrale 20.  As the inner surface of the sleeve 31 can not be damaged by its passage on the knurling 21, there is no risk of leakage at the inner surface of the sleeve 31 applied against the smooth portion of the sleeve. central electrode 20.
En fonctionnement, même si la dilatation de l'électrode centrale repousse la collerette d'appui 42 du connecteur 40 de la surface arrière de la collerette 32 du joint 30, cela ne modifie pas la tenue du manchon 31 dans l'alésage 1 1 et autour de l'électrode centrale 20 et ne crée pas de défaut d'étanchéité. Ainsi, en résumé, à froid comme à chaud, malgré les glissements possibles entre le corps tubulaire 10, le manchon 31 et l'électrode centrale 20, l'étanchéité de la cavité reste garantie. In operation, even if the expansion of the central electrode pushes the support flange 42 of the connector 40 of the rear surface of the flange 32 of the seal 30, this does not modify the resistance of the sleeve 31 in the bore 1 1 and around the central electrode 20 and does not create a sealing defect. So, in summary, cold as hot, despite possible slippage between the tubular body 10, the sleeve 31 and the central electrode 20, the sealing of the cavity remains guaranteed.
La figure 1A montre la bougie de préchauffage à l'état terminé, après le sertissage. Figure 1A shows the glow plug in the finished state after crimping.
La figure 2A montre la première étape de montage de l'extrémité arrière de la bougie de préchauffage 1, l'extrémité avant étant déjà assemblée, c'est-à-dire la cartouche chauffante étant fixée au corps 10 et à l'extrémité avant de l'électrode centrale 20. La vue en coupe non assemblée de la figure 2A permet de voir plus précisément la forme des différents éléments au niveau de leurs jonctions.  FIG. 2A shows the first step of mounting the rear end of the glow plug 1, the front end being already assembled, that is to say the heating cartridge being fixed to the body 10 and to the front end of the central electrode 20. The unassembled sectional view of FIG. 2A makes it possible to see more precisely the shape of the different elements at their junctions.
La figure 3A montre l'assemblage de l'extrémité arrière de la bougie de préchauffage 1 avant le sertissage et après sertissage la bougie de préchauffage 1 est à l'état terminé, représentée à la figure 1A.  Figure 3A shows the assembly of the rear end of the glow plug 1 before crimping and after crimping the glow plug 1 is in the completed state, shown in Figure 1A.

Claims

R E V E N D I C A T I O N S R E V E N D I C A T IO N S
1 °) Bougie de préchauffage à cartouche en céramique comprenant : 1 °) Ceramic cartridge glow plug comprising:
- un corps métallique tubulaire ( 10) muni d'un filetage ( 12) pour se visser dans la culasse du moteur et portant l'élément chauffant dans la cartouche, le corps ( 10) étant traversé par une électrode centrale (20) reliée à une extrémité de l'élément chauffant dont l'autre extrémité est reliée au corps faisant la liaison à la masse, a tubular metal body (10) provided with a thread (12) for screwing into the cylinder head of the engine and carrying the heating element in the cartridge, the body (10) being traversed by a central electrode (20) connected to one end of the heating element whose other end is connected to the body making the connection to ground,
- le corps ( 10) portant un connecteur (40) installé sur l'extrémité moletée de l'électrode (20) et relié à celle-ci par sertissage en étant isolé électriquement du corps, the body (10) carrying a connector (40) installed on the knurled end of the electrode (20) and connected thereto by crimping being electrically isolated from the body,
bougie de préchauffage caractérisée en ce que glow plug characterized in that
- l'extrémité arrière ( 13) du corps ( 10) se termine par une surface d'appui ( 131) comportant un lamage ( 15) recevant la collerette (32) du joint (30) dans laquelle débouche l'alésage ( 1 1) ,  - The rear end (13) of the body (10) terminates in a bearing surface (131) having a countersink (15) receiving the flange (32) of the seal (30) into which the bore (1 1 ),
- le moletage (2 1) de l'extrémité arrière de l'électrode centrale (20) a un diamètre extérieur (Di) inférieur au diamètre (Do) de la partie lisse de l'électrode centrale (20) ,  the knurling (2 1) of the rear end of the central electrode (20) has an outside diameter (Di) smaller than the diameter (Cd) of the smooth part of the central electrode (20),
- un joint (30) formé d'un manchon (31) comportant une collerette (32), le joint étant logé dans l'intervalle entre l'électrode centrale (20) et l'extrémité ( 14) de l'alésage par un montage serré,  - a seal (30) formed of a sleeve (31) having a flange (32), the seal being housed in the gap between the central electrode (20) and the end (14) of the bore by a tight fitting,
- le manchon (31) a une épaisseur (e) supérieure à la dimension de l'intervalle entre la surface lisse de l'électrode centrale (20) et l'alésage ( 1 1) [(D3-Do) / 2] , ce manchon étant inséré de force dans l'intervalle (i) et la collerette (32) venant s'appuyer en butée contre la face d'appui ( 131) de la partie arrière ( 13) et la collerette d'appui (42) du connecteur (40), et  the sleeve (31) has a thickness (e) greater than the dimension of the gap between the smooth surface of the central electrode (20) and the bore (11) [(D3-Do) / 2], this sleeve being inserted by force into the gap (i) and the flange (32) abutting abutting against the bearing face (131) of the rear portion (13) and the bearing flange (42) the connector (40), and
- le diamètre intérieur (D4) du manchon (31) est supérieur au diamètre extérieur (Di) du moletage (2 1) . 2°) Bougie de préchauffage selon la revendication 1 ,  the inside diameter (D4) of the sleeve (31) is greater than the outside diameter (Di) of the knurling (2 1). 2 °) Glow plug according to claim 1,
caractérisée en ce que characterized in that
le joint (30) est en polyamide notamment en copolymère PA6/6 de ca- prolactame PA6. the seal (30) is made of polyamide, in particular of PA6 / 6 copolymer of cocaine PA6.
EP15718895.4A 2014-05-13 2015-04-29 Preheater electrode with insulating seal Withdrawn EP3143332A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1454232A FR3021094A1 (en) 2014-05-13 2014-05-13 PREHEATING ELECTRODE WITH INSULATION SEAL
PCT/EP2015/059266 WO2015173017A1 (en) 2014-05-13 2015-04-29 Preheater electrode with insulating seal

Publications (1)

Publication Number Publication Date
EP3143332A1 true EP3143332A1 (en) 2017-03-22

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EP15718895.4A Withdrawn EP3143332A1 (en) 2014-05-13 2015-04-29 Preheater electrode with insulating seal

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EP (1) EP3143332A1 (en)
JP (1) JP2017510789A (en)
CN (1) CN106461217A (en)
FR (1) FR3021094A1 (en)
WO (1) WO2015173017A1 (en)

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Publication number Priority date Publication date Assignee Title
DE102016108592B4 (en) * 2016-05-10 2018-06-28 Borgwarner Ludwigsburg Gmbh Glow plug and method of manufacturing a glow plug

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JPS5367034A (en) * 1976-11-25 1978-06-15 Ngk Spark Plug Co Ltd Manufacturing method of theath glow plug
JPS53141840A (en) * 1977-05-16 1978-12-11 Ngk Spark Plug Co Ltd Manufacturing method of sheathed glow plug
DE8427789U1 (en) * 1984-09-21 1986-01-23 Robert Bosch Gmbh, 7000 Stuttgart Sheathed-element glow plugs for internal combustion engines
JPH09273752A (en) * 1996-04-01 1997-10-21 Isuzu Ceramics Kenkyusho:Kk Self-current-control type glow plug
DE19805578C1 (en) * 1998-02-12 1999-04-22 Bosch Gmbh Robert Glow pin plug for internal combustion engine
US6064039A (en) * 1998-04-15 2000-05-16 Ngk Spark Plug Co., Ltd. Glow plug with small-diameter sheath tube enclosing heating and control coils
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FR3021094A1 (en) 2015-11-20
JP2017510789A (en) 2017-04-13
CN106461217A (en) 2017-02-22
WO2015173017A1 (en) 2015-11-19

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