DK167502B1

DK167502B1 - FUEL ENGINE FOR COMBUSTION ENGINES

Info

Publication number: DK167502B1
Application number: DK169891A
Authority: DK
Inventors: Poul Erik Larsen; Peter Sunn Pedersen
Original assignee: Man B & W Diesel Gmbh
Priority date: 1991-10-04
Filing date: 1991-10-04
Publication date: 1993-11-08
Also published as: KR940702982A; PL169883B1; EP0606371B1; HRP920658A2; DK169891D0; JP3027191B2; TW250529B; DK169891A; JPH06511064A; HRP920658B1; DE69204075T2; EP0606371A1; KR100253673B1; DE69204075D1; WO1993007386A1

Description

DK 167502 B1DK 167502 B1

Opfindelsen anerår en brændselsinjektor til forbrændingsmotorer, omfattende et i injektorens ydre hus fast anbragt hult gliderstyr, hvis forreste ende er udformet som en fortil lukket og med en central boring 5 forsynet forstøver, der til indsprøjtning af forstøvet brændsel har et antal tværgående forstøverhuller i sin sidevæg, en i styret aksialt forskydelig ventilglider til åbning og lukning af forstøverhullerne, hvilken glider har et forreste afsnit med et af et skaft båret 10 cylindrisk endeafsnit, som for afspærring af forstøverhullerne i ventilens lukkede stilling er lejret med tæt pasning i forstøverens boring, og hvor injektoren har en strømningspassage, gennem hvilken brændsel under tryk kan strømme forbi ventilglideren samt til forstø-15 verhullerne, når glideren indtager sin åbnestilling, hvor dens endeafsnit blotter hullerne, samt en på glideren mod brændselstrykket virkende lukkefjeder til fastholdelse af glideren i dennes lukkestilling.The invention relates to a fuel injector for internal combustion engines, comprising a hollow sliding guide fixed in the outer housing of the injector, the front end of which is formed as a pre-closed and provided with a central bore 5 atomizer which has a number of transverse atomizer holes for injecting fuel into the side wall. a slidable axially slid valve slider for opening and closing the nebulizer holes, said slider having a front portion with a 10-cylindrical end portion supported by a shaft, which for locking the nebulizer holes in the valve closed position is positioned with close fit into the nebulizer bore, and the injector has a flow passage through which fuel under pressure can flow past the valve slider as well as to the nozzle holes as the slider occupies its open position where its end section exposes the holes, and a closing spring acting on the slider to maintain the slider in its closing position.

Fra dansk patent nr. 149 141 kendes en brænd-20 selsinjektor af denne type, hvor ventilglideren og dennes forreste afsnit, som rager ned i forstøveren, er forholdsvis stive i tværretningen, hvilket gør det påkrævet, at glideren er monteret fuldstændig koaksialt med boringen i forstøveren. Selv en ganske ringe mang-25 lende opretning mellem glideren og forstøverens boring kan føre til svigt i brændselsinjektoren.From Danish Patent No. 149 141 there is known a fuel injector of this type, in which the valve slider and its front section projecting down into the nebulizer are relatively rigid in the transverse direction, which makes it necessary for the slider to be mounted completely coaxially with the bore in atomizer. Even a slight lack of alignment between the slider and the nebulizer bore can lead to failure of the fuel injector.

Det bageste gliderafsnit, der er lejret i gliderstyret, har forholdsvis stor diameter og er slebet på mål til at passe i gliderstyret, mens det ned i for-30 støverens boring ragende forreste gliderafsnit har mindre diameter og er slebet på mål, så at det cylindriske endeafsnit er lejret med tæt pasning i forstøverens boring. For at sikre tæt afspærring af forstøverhullerne, selv når brændselstrykket i strømningspassa-35 gen umiddelbart førend og efter selve brændselsindsprøjtningen kan nå op på meget høje værdier, såsom 300 2The rear slider section, which is mounted in the slider guide, has a relatively large diameter and is ground to dimensions to fit the slider guide, while the front slider section protruding into the bore of the sprayer has a smaller diameter and is grinded to the dimensions so that the cylindrical end sections are enclosed with tight fit in the nebulizer bore. To ensure tight shut-off of the nebulizer holes, even when the fuel pressure in the flow passage immediately before and after the fuel injection itself can reach very high values, such as 300

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forstøverens boring, hvorfor klaringen mellem endeafsnittet og boringen typisk vil være 10-15 pm. Kravet om fuld koaksialitet mellem gliderens endeafsnit og det i 5 gliderstyret lejrede bageste afsnit nødvendiggør at de to afsnit slibes i samme opspænding, hvorfor forbindelsen mellem endeafsnittet og den resterende del af glideren må have så stor stivhed mod tværudbøj ning, at den af slibeorganets spåntryk frembragte tværkraft ikke 10 fører til nogen nævneværdig udbøjning af glideren.the nebulizer bore, which is why the clearance between the end section and the bore will typically be 10-15 pm. The requirement for full coaxiality between the end section of the slider and the rear section stored in the slider guide requires the two sections to be sanded in the same clamping, so the connection between the end section and the remaining part of the slider must have such stiffness against transverse deflection that it produced by the grinding pressure of the grinding member. transverse force 10 does not cause any significant deflection of the slider.

Inden slibningen er den af stål bestående glider hærdet til glashård tilstand, hvilket betyder at såvel håndteringen som slibningen af glideren skal ske med stor forsigtighed for at hindre glideren i at knæk-15 ke som følge af dens skørhed. Dette fører sammen med de høje krav til koaksialitet og tolerancer af de slebne overflader til, at glideren er omkostningskrævende at fremstille. Det er endvidere en ulempe, at hele glideren skal udskiftes, når endeafsnittet er nedslidt. For-20 sendelse og udskiftning af glideren er også besværlig-gjort af gliderens skørhed, idet selv en ganske ringe tværgående slagpåvirkning kan føre til, at glideren knækker.Prior to grinding, the steel slider is hardened to glass hard state, which means that both the handling and grinding of the slider must be done with great care to prevent the slider from breaking due to its brittleness. This, together with the high demands on coaxiality and tolerances of the abrasive surfaces, make the slider costly to manufacture. Furthermore, it is a disadvantage that the entire slide should be replaced when the end section is worn. Dispatching and replacing the slider is also hampered by the brittleness of the slider, as even a very slight transverse impact can cause the slider to break.

Det er opfindelsens formål at anvise en glider 25 som har længere levetid end den kendte glider, og som er lettere at fremstille, håndtere og udskifte.It is an object of the invention to provide a slider 25 which has a longer life than the known slider and which is easier to manufacture, handle and replace.

Med henblik herpå er brændselsinjektoren ifølge opfindelsen ejendommelig ved, at den aksiale længde af gliderens endeafsnit højst er af samme størrelsesorden 30 som diametren af boringen i forstøveren, og at skaftets længde er mange gange længere end endeafsnittets aksiale længde.To this end, the fuel injector according to the invention is characterized in that the axial length of the end section of the slider is at most of the same order of magnitude 30 as the diameter of the bore in the nebulizer and that the length of the shaft is many times longer than the axial length of the end section.

Som følge af den korte længde af gliderens endeafsnit og skaftets lange længde, er gliderens forreste 35 afsnit så fleksibelt, at boringen i forstøveren automatisk vil rette gliderens endeafsnit ind efter sin DK 167502 B1 3 egen længdeakse. så at endeafsnittet ikke nødvendigvis skal være helt koaksialt med det i gliderstyret lejrede bageste gliderafsnit. Da gliderens endeafsnit selv ret-ter sig ind efter boringen, vil nedslidningen af ende-5 afsnittet og forstøveren være mindsket i forhold til i den kendte injektor, hvor selv en meget lille skævhed mellem endeafsnittet og forstøveren kan føre til rivninger og dermed hurtig nedslidning af denne.Due to the short length of the slider end section and the long length of the shaft, the front 35 sections of the slider are so flexible that the bore in the nebulizer will automatically align the slider end section according to its own longitudinal axis 16. so that the end section does not necessarily have to be fully coaxial with the rear slide section stored in the slide guide. Since the end section of the slider itself aligns after the drilling, the wear of the end section and the nebulizer will be reduced compared to the known injector, where even a very slight bias between the end section and the nebulizer can lead to tearing and thus rapid wear of the this.

Da det ikke længere er nødvendigt, at gliderens 10 forreste og bageste endeafsnit skal være fuldstændig koaksiale, kan gliderens forreste afsnit fremstilles uafhængigt af det bageste afsnit. Ifølge opfindelsen udnyttes dette til at lette fremstillingen af glideren, ved at den cylindriske yderside af gliderens forreste 15 afsnit færdigslibes på mål uafhængigt af slibningen af det gliderafsnit, der skal lejres i gliderstyret. Ved at slibe det forreste, forholdsvis tynde og det bageste, forholdsvis tykke gliderafsnit i hver sin opspænding, opnås dels en stor reduktion af risikoen for 20 knækning af det forreste, glashårde gliderafsnit under slibningen, fordi dette afsnit ikke skal bære vægten af den samlede glider, dels kan slibningen af det tykke, bageste afsnit ske med stort spåntryk og dermed hurtigt, fordi den ringe styrke af det forreste glideraf-25 snit ikke længere er begrænsende for spåntrykket.Since it is no longer necessary for the front and rear end sections of the slider 10 to be completely coaxial, the front section of the slider can be manufactured independently of the rear section. According to the invention, this is utilized to facilitate the manufacture of the slider by finishing the cylindrical exterior of the front 15 sections of the slider to dimensions independently of the grinding of the slider section to be mounted in the slider guide. By grinding the front, relatively thin and the rear, relatively thick slider sections in each clamp, a major reduction in the risk of 20 cracking of the front, glass-hard slider section during grinding is achieved, because this section does not carry the weight of the total slider , in part, the grinding of the thick rear section can be done with high chip pressure and thus quickly, because the low strength of the front slider section is no longer limiting the chip pressure.

Når det forreste gliderafsnit er nedslidt og skal udskiftes, er det ifølge opfindelsen muligt kun at udskifte det forreste gliderafsnit omfattende skaftet og endeafsnittet, og dermed lade det bageste glideraf-30 snit forblive i drift, hvilket i væsentlig grad reducerer omkostningerne ved udskiftningen og letter forsendelsen og håndteringen af de nødvendige reservedele.When the front slide section is worn and needs to be replaced, it is possible according to the invention to replace only the front slide section including the shaft and end section, thus leaving the rear slide section operational, which substantially reduces the cost of replacement and facilitates shipping. and handling the required spare parts.

Gliderens levetid er yderligere forøget i en fo-retrukken udførelsesform, hvor i det mindste den forre-35 ste del af endeafsnittets cylindriske yderside består af et erosionsmodstandsdygtigt materiale, såsom Stel- 4The life of the slider is further increased in a preferred embodiment, wherein at least the front part of the cylindrical outer surface of the end section consists of an erosion resistant material such as frame 4.

Ul\ Ib/bUZ b l lite 6. Det erosionsmodstandsdygtige materiale mindsker det slid af endeafsnittets forende, som kan opstå når endeafsnittet under injektorens åbning blotter forstøverhullerne, og brændslet begynder at strømme med meget 5 store hastigheder ud gennem forstøverhullerne. De store strømningshastigheder, som ved ventilens åbning forekommer umiddelbart ud for yderenden af endeafsnittet, påfører dette store belastninger. Det erosionsmodstandsdygtige materiale er i stand til at optage disse 10 belastninger, hvilket forlænger gliderens levetid.Ul / Ib / bUZ b l lite 6. The erosion-resistant material reduces the wear of the end section front end which can occur when the end section below the injector opening exposes the nebulizer holes and the fuel begins to flow through the nebulizer holes at very high speeds. The large flow rates which occur at the valve opening immediately beyond the end of the end section impose large loads on it. The erosion resistant material is able to absorb these 10 loads, extending the life of the slider.

Eksempler på udførelsesformer for opfindelsen beskrives herefter nærmere med henvisning til den skematiske tegning, hvorpå fig. 1 er et aksialt snit gennem en udførelses-15 form for injektoren, med glideren vist i sin åbnestilling, fig. 2 et aksialt snit i større skala gennem den forreste del af den i fig. 1 viste injektor, med glideren vist i lukkestillingen, 20 fig. 3 i delsnit et sidebillede af gliderens forreste afsnit, fig. 4 et tværsnit gennem glideren efter linien IV-IV i fig. 3, fig. 5 et aksialt snit gennem den forreste del 25 af en anden udførelsesform for injektoren, og fig. 6 et tværsnit efter linien VI-VI i fig. 5 gennem gliderens forreste afsnit.Examples of embodiments of the invention will now be described in more detail with reference to the schematic drawing, in which fig. 1 is an axial section through an embodiment of the injector, with the slider shown in its open position; FIG. 2 is a larger-scale axial section through the anterior portion of FIG. 1, with the slider shown in the closing position, FIG. 3 is a partial sectional side view of the front section of the slider; FIG. 4 is a cross-section through the slide along line IV-IV of FIG. 3, FIG. 5 is an axial section through the front portion 25 of another embodiment of the injector; and FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5 through the front section of the slider.

Den i fig. 1, 2 og 5 viste brændselsinjektor har et langstrakt ydre hus l, som ved sin bageste ende 30 har et hoved 2, hvormed injektoren på kendt vis kan monteres i en forbrændingsmotors cylinderdæksel og tilsluttes en ikke vist brændselspumpe. I hovedet 2 er der en brændselsolietilgang 3, som er i strømnings-forbindelse med en kanal 4, som går gennem et cen-35 trait trykstykke 5 og et ventillegeme 6, der er lejret i et ventilhus 7, hvis bageste ende ligger an mod DK 167502 B1 5 et irsrnau'vendsn.de bryst p3 trykstykket 5, 05 hvis for reste ende har en konisk flade, som holdes i tæt anlæg mod en modsvarende konisk flade på et gliderstyr 8, der ved sin bageste ende har tæt pasning i huset 1 og 5 ved sin forreste ende bærer en forstøver 9, der rager ud gennem huset 1 og ind i den ikke viste motorcylinders forbrændingskammer, når injektoren er monteret på cylinderdækslet.The FIG. 1, 2 and 5 have an elongated outer housing 1, which at its rear end 30 has a head 2, which can be mounted in a known manner in the cylinder cover of an internal combustion engine and connected to a fuel pump (not shown). In the head 2 there is a fuel oil inlet 3 which is in flow communication with a duct 4 passing through a centrifugal pressure piece 5 and a valve body 6 which is mounted in a valve housing 7, the rear end of which contacts the DK 167502 B1 5 is an annular breast of p3 pressure member 5, 05 whose foremost end has a tapered surface held tightly against a corresponding tapered surface of a slide guide 8 which at its rear end has a tight fit in the housing 1 and 5 at its front end carry a nebulizer 9 projecting through housing 1 and into the combustion chamber of the engine not shown, when the injector is mounted on the cylinder cover.

En generelt med 10 betegnet glider er aksialt 10 forskydelig indvendig i gliderstyret 8 og har et bageste afsnit 11, hvis cylindriske yderside er slebet på mål og er lejret med tæt pasning i en central styreboring i gliderstyret 8. Gliderafsnittet 11 bærer et forreste gliderafsnit 12, som er væsentlig tynde-15 re end det bageste afsnit 11 og rager ned i en central boring 13 i forstøveren.A generally designated slider 10 is axially slidable internally in the slider guide 8 and has a rear section 11 whose cylindrical outer surface is ground to a dimension and is closely seated in a central guide bore of the slider guide 8. The slider section 11 carries a forward slider section 12, which is substantially thinner than the rear section 11 and projects into a central bore 13 of the nebulizer.

Et ind i gliderens bageste afsnit forløbende centralt rør 14 er udformet ud i et med gliderstyret 8 og har et fremad vend ende bryst, som begrænser den 20 bagudgående bevægelse af glideren 10.A central tube 14 extending into the rear section of the slide is formed integrally with the slide guide 8 and has a forward facing chest which restricts the backward movement of the slide 10.

I et hulrum 15 i gliderstyret er der optaget en lukkefjeder 16, som bagtil ligger an mod gliderstyret 8 og fortil mod et bagudvendende bryst 17 på den bageste ende af gliderafsnittet 11, så at lukke-25 fjederen belaster glideren fremefter mod den i fig. 2 viste lukkestilling.In a cavity 15 in the slide guide, a closing spring 16 is provided which rests rearwardly against the slide guide 8 and anteriorly to a rearward facing chest 17 on the rear end of the slide section 11, so that the closing spring loads the slide forward towards the one shown in FIG. 2.

Tilgangskanalen 4 står gennem tværgående boringer og et efterfølgende ventilsæde 18 i forbindelse med en gennem røret 14 gående strømningspassage 30 19, som fortil udmunder i et i glideren udformet for delingskammer 20, som gennem tværgående boringer 21 står i strømningsforbindelse med et ringformet kammer 22 afgrænset mellem gliderens yderside og de omgivende dele af gliderstyret. Ved den forreste ende af kam-35 meret 22 er der i gliderstyret 8 udformet en konisk sædeflade 23, og glideren har ved forenden af afsnit- DK 167502 Bl 6 tet 11 en modsvarende konisk sædeflade 24, som i injektorens lukkestilling er presset tætnende i anlæg mod fladen 23 af lukkefjederen 16.The access channel 4 stands through transverse bores and a subsequent valve seat 18 in connection with a flow passage 30 19 passing through the tube 14, which leads to the front of a dividing chamber 20 formed in the slide, which through flow bores 21 communicates with an annular chamber 22 bounded between the outside of the slide and the surrounding parts of the slide guide. At the front end of the chamber 22, a tapered seat surface 23 is formed in the slide guide 8 and the slider has at the front end of the section 11 a corresponding tapered seat surface 24 which is sealed in abutment in the closing position of the injector. toward the face 23 of the closing spring 16.

Det forreste afsnit 12 af glideren har ved sin 5 bageste ende et gevindstykke 25, som er indskruet i en central boring i den forreste ende af gliderafsnittet 11, så at et bagudvendende bryst 26 på afsnittet 12 ligger an mod forenden af afsnittet 11. En gennem sammenhørende boringer i glider af snittene 11 10 og 12 indsat sikringsstift 27 hindrer det forreste afsnit 12 i utilsigtet at dreje sig fri af det bageste afsnit 11. Denne sikring mod løsgåelse kan dog også udføres på anden vis, f.eks. med lim såsom Loctite (reg.var.). Brystet 26 går fremefter over i et for-15 holdsvis tyndt og langstrakt skaft 28, hvis forreste ende bærer et endeafsnit 29 med en cylindrisk yderside 30, som er lejret med tæt pasning i forstøverens boring 13.The front portion 12 of the slider has at its rear end a threaded piece 25 which is screwed into a central bore at the front end of the slider section 11 so that a rearward facing chest 26 of the section 12 abuts the front end of the section 11. associated bores in slides of the sections 11 10 and 12 inserted securing pin 27 prevents the front section 12 from inadvertently pivoting away from the rear section 11. However, this protection against loosening can also be performed in other ways, e.g. with adhesives such as Loctite (reg. var.). The chest 26 then proceeds into a relatively thin and elongated shaft 28, the forward end of which carries an end portion 29 with a cylindrical outer surface 30, which is tightly fitted in the nebulizer bore 13.

I forstøverens væg er der et antal tværgående 20 forstøverhuller 31, der er således beliggende, at endeafsnittet 29 afspærrer forstøverhullerne, når injektoren står i den i fig. 2 viste lukkestilling, mens endeafsnittet 29 i injektorens åbnestilling (fig. 1) er bevæget så langt tilbage, at forstøverhullerne er 25 fuldstændig frilagte.In the wall of the nebulizer, there are a plurality of transverse nebulizer holes 31 located such that the end portion 29 blocks the nebulizer holes when the injector is in the position shown in FIG. 2, while the end portion 29 of the injector's open position (Fig. 1) is moved so far back that the nebulizer holes 25 are completely exposed.

Når ventillegemet 6 ligger an mod ventilsædet 18, kan forvarmet olie via en tværgående boring i trykstykket 5 gennemstrømme injektoren og holde den varm. Når brændselsoliens tryk i tilgangen 3 stiger 30 kraftigt umiddelbart førend indsprøjtningen skal initieres, vil ventillegemet 6 forskydes bagover til den i fig. 1 viste stilling og afspærre passagen for cirkulerende olie, hvorefter brændselsolien strømmer forbi ventilsædet 18, ned gennem passagen 19 og ud i kam-35 meret 22, hvor trykket i olien opbygges, indtil det overvinder kraften fra lukkefjederen 17, og glideren DK 167502 B1 7 bevæges bagud fra den i fig. 2 viste lukkestilling, Umiddelbart efter at sædefladerne 23 og 24 er bevæget væk fra hinanden, vil brændselsolien strømme fremad i rummet omkring skaftet 28 og passere gennem udsparin-5 ger 32 i dette frem til den del af boringen 13, der ligger foran endeafsnittet 29. Da endeafsnittet 29 i injektorens lukkede stilling strækker sig et stykke fremad forbi forstøverhullerne 31, vil der ske en trykopbygning i brændselsolien foran endeafsnittet 29, 10 inden dette blotter forstøverhullerne, hvilket betyder at brændselsolien stort set fra starten af indsprøjtningen indsprøjtes ved fuldt tryk, hvilket sikrer en god forstøvning og forbrænding.When the valve body 6 abuts the valve seat 18, preheated oil can flow through the injector 5 through a transverse bore in the injector 5 and keep it warm. When the pressure of the fuel oil in the inlet 3 increases 30 immediately before the injection is to be initiated, the valve body 6 will be shifted backward to that of FIG. 1 and shut off the passage for circulating oil, after which the fuel oil flows past the valve seat 18, down through the passage 19 and into the chamber 22, where the pressure in the oil builds up until it overcomes the force of the closing spring 17 and the slider DK 167502 B1 7 is moved backwards from the one shown in FIG. 2, immediately after the seat surfaces 23 and 24 are moved away from each other, the fuel oil will flow forward in the space around the shaft 28 and pass through recesses 32 therein to the portion of bore 13 which lies in front of the end section 29. As the end portion 29, in the closed position of the injector, extends a little forward past the nebulizer holes 31, there will be a build-up of pressure in the fuel oil in front of the end section 29, 10 before blotting the nebulizer holes, which means that the fuel oil is injected at full pressure from the start of the injection, ensuring a good atomization and combustion.

Gliderens forreste afsnit 12 og bageste afsnit 15 11 færdigfremstilles som to særskilte enheder, der først samles umiddelbart førend glideren 10 monteres i injektoren. Det forholdsvis tykke gliderafsnit 11 kan som følge af sin store stivhed mod tværudbøjning bearbejdes med højt spåntryk.The front section 12 of the slider and rear section 15 11 are finished as two separate units, which are assembled immediately before the slide 10 is mounted in the injector. The relatively thick slider section 11 can be machined with high chip pressure due to its high stiffness against transverse deflection.

2o Det forreste afsnit 12 er i den i fig. 2, 3 og 4 viste udførelsesform opbygget af to elementer, nemlig skaftet 28 bestående af et ikke-skørt materiale og en ring 33 bestående af et erosionsmodstandsdygtigt materiale, såsom Stellite 6. Skaftet 32 har 25 ved sin forreste ende større diameter og er her udformet med tre efter omkredsen fordelte, langsgående udsparinger 32, der som nævnt tillader brændselsolien at passere indvendigt forbi ringen 33. Udsparingerne 32 efterlader i skaftets forreste ende tre radialt ud-30 ragende flige 34, hvortil ringen 33 er fastgjort, eksempelvis ved hjælp af hårdlodning. Som loddemateriale kan der eksempelvis anvendes Alloy 50. Denne todelte udførelse af gliderens forreste afsnit 12 er særdeles velegnet for massefremstilling, idet ringen 33 og 35 skaftet 28 begge er lette at fremstille på en NC-au-tomat. Om ønsket kan skaftet naturligvis udformes med flere end tre radialt udragende flige.2o the front section 12 is in the embodiment shown in FIG. 2, 3 and 4 are constructed of two elements, namely the shaft 28 consisting of a non-brittle material and a ring 33 consisting of an erosion resistant material such as Stellite 6. The shaft 32 has a larger diameter at its front end and is formed here. with three circumferentially distributed longitudinal recesses 32 which, as mentioned, allow the fuel oil to pass internally past the ring 33. The recesses 32 leave at the front end of the shaft three radially projecting tabs 34 to which the ring 33 is attached, for example by means of brazing. For example, solder can be used Alloy 50. This two-part embodiment of the front section 12 of the glider is particularly suitable for mass production, as the ring 33 and 35 shaft 28 are both easy to manufacture on an NC machine. Of course, if desired, the shaft can be formed with more than three radially projecting tabs.

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Li V XW ^XXVIVX ViiW Vi. fa V·^ w- WM X. WX* .*. W -k Xrf Λ Mil υΛΜΧ fremstilles i et lille styktal, kan det hensigtsmæssigt udformes som vist i fig. 5 og 6. Det forreste afsnit er her fremstillet ud fra et enkelt stålemne, der i det 5 forreste endeafsnit og et stykke op ad siden svarende til den påtænkte pasflade mod forstøverens boring 13 har fået påsvejst et lag af erosionsmodstandsdygtigt materiale, såsom Stellite 6. Brystet 26 og skaftet 28 drejes ud, og der bores fra emnets forende en cen-10 tral boring 35, som er længere end det cylindriske endeafsnit 29. Derefter forsynes det bagved endeafsnittet 29 beliggende skaftafsnit 36, som har mindre diameter end endeafsnittet 29 men større diameter end den bagved liggende del af skaftet 28, med et 15 passende antal, f.eks. fire, efter omkredsen fordelte, langsgående udfræsninger 37 med en radial dybde, der er lidt større end vægtykkelsen af det ringformede endeafsnit 29, så at udfræsningerne udmunder i boringen 35 og skaber strømningsforbindelse mellem den bagved 20 og foran endeafsnittet 29 liggende del af forstøverens boring 13. Som afsluttende bearbejdning af det forreste gliderafsnit 12, færdigslibes ydersiden af endeafsnittet 29 på mål.Li V XW ^ XXVIVX ViiW Vi. fa V · ^ w- WM X. WX *. *. W -k Xrf Λ Mil υΛΜΧ is produced in a small number, it can conveniently be designed as shown in FIG. 5 and 6. The front section is here made from a single steel blank, which in the front end section and a piece upwards corresponding to the intended fit surface against the nebulizer bore 13 has a weld of erosion-resistant material such as Stellite 6. The chest 26 and shaft 28 are turned out and a central bore 35 which is longer than the cylindrical end portion 29 is drilled from the front end of the workpiece. Then, the shaft portion 36 located behind the end section 29 which is smaller in diameter than the end section 29 is provided. diameter than the underlying portion of the shaft 28, with a suitable number, e.g. four circumferentially spaced longitudinal cut-outs 37 having a radial depth slightly greater than the wall thickness of the annular end portion 29 such that the cut-outs open into the bore 35 and provide flow connection between the rear portion 20 and in front of the end portion 29 of the nebulizer bore 13 As a final machining of the front slider section 12, the exterior of the end section 29 is finished on the finish.

Den strømningspassage, som tillader brændslet at 25 strømme forbi glideren, omfatter i den i fig. 2 viste udførelsesform udsparingerne 32, mens den omfatter udfræsningerne 37 og boringen 35 i den i fig. 5 viste udførelsesform.The flow passage which allows the fuel to flow past the slider comprises in the embodiment shown in FIG. 2, the recesses 32, while the cutters 37 and the bore 35 in the embodiment of FIG. 5.

I stedet for den viste gevindsamling mellem de 30 to yderafsnit, kan afsnittene naturligvis samles på anden vis, eksempelvis ved hjælp af prespasning eller en lignende forbindelsesmetode. Skaftet kan endvidere udformes på anden vis, eksempelvis som flere parallelle og tynde stænger, som forbinder skaftets bageste af-35 snit med endeafsnittet 29. Den for opfindelsen væsentlige egenskab ved skaftet, er dets fleksibilitet, DK 167502 B1 n 9 som tillader endeafsnittet 29 at rette sig ind efter boringen 13 uafhængigt af det bageste gliderafsnits lejring i gliderstyret 8.Of course, instead of the threaded joint shown between the two outer sections, the sections can be assembled in another way, for example by means of press fit or a similar connection method. The shaft can also be formed in other ways, for example as several parallel and thin rods connecting the rear section of the shaft to the end section 29. The essential feature of the invention for the shaft is its flexibility, which allows the end section 29 to align with the bore 13 independently of the rear slide section bearing in the slide guide 8.

Claims

An internal combustion engine fuel injector, comprising a hollow slider guide (8) fixed in the outer housing (1) of the injector, the front end of which is formed as a front closure and provided with a central bore (13) for injection (9). of nebulized fuel has a plurality of transverse nebulizer holes (31) in its side wall, a valve slider (10) in controlled axially displaceable for opening and closing the nebulizer holes, which slider has a front portion (12) with one of a shaft (28) carried cylindrical end portion (29), which for tightening the nebulizer holes in the closed position of the valve, is sealed tightly in the nebulizer bore (13) and wherein the injector has a flow passage, (3,4,19,21,13,32) through which fuel under pressure 15 may flow past the valve slider (10) as well as to the nebulizer holes (31) as the slider assumes its open position, where its end portion (29) exposes the holes, and a closing spring (1) acting on the slider. 6) for holding the slider in its closing position, characterized in that the axial length of the end section (29) of the slider is at most of the same order of magnitude as the diameter of the bore (13) in the nebulizer and that the length of the shaft (28) is many times longer than the axial length of the end section (29).

Fuel injector according to claim 1, characterized in that the end section (29) is a cylindrical ring (33) fixed to the shaft (28).

Fuel injector according to claim 2, characterized in that the shaft (28) at its end facing the ring 30 has radially projecting tabs (34), preferably at least three, to which the ring (33) is attached, preferably by soldering.

Fuel injector according to claim 1, characterized in that the shaft (28) and the end section (29) are manufactured from. a single output blank whose end-section forming end is formed with a central bore (35) which communicates in flow in the region above the end section with the 5 portion of the nebulizer central bore (13) located above the end section.

Fuel injector according to one of the preceding claims, characterized in that at least the front part of the cylindrical outer surface (30) of the end section consists of an erosion-resistant material, such as Stellite 6.

Fuel injector according to one of the preceding claims, characterized in that the front portion (12) of the slider comprising the shaft (28) and the end portion (29) is interchangeable as a unit independent of the remaining part of the slider (10).

Method for use in the manufacture of a slider for a fuel injector according to any one of claims 1-6, characterized in that the cylindrical outer surface (30) of the front section (12) of the slider is finished abrading to dimensions independent of the grinding of the slider. section (11) to be stored in the slide guide (8).