EP2450556B1 - Connection assembly for a tubular fuel conduit - Google Patents

Description

The invention relates to a connection arrangement for a tubular fuel line referred to in the preamble of claim 1 Art.

In such, the US PS 3,845,748 Removable connection arrangement, the sealing surface of a pressure nipple, which is formed at the inserted into the channel of the cylinder head end of the fuel line, pressed against a counter-sealing surface on the nozzle holder by means of a pressure transmission arrangement which transmits the force to the nipple, which when screwing and tightening a Überwurfschraubelementes in a formed in the region of the inlet opening of the channel internal thread is generated. This pressure transmission arrangement consists of two parts surrounding the fuel line coaxially, namely a pressure ring directly adjacent to a pressure receiving surface of the pressure nipple and a pressure tube, which bridges the distance between the pressure ring and the Überwurf screw in the assembled state.

Since it can not be ruled out that under very high pressure fuel and / or engine oil penetrates into the free spaces, which must be present for reasons of mountability between the outer surface of the fuel line and the pressure transmission assembly on the one hand and the pressure transmission assembly and the inner wall of the channel on the other hand it is necessary to seal the channel to the outside of the cylinder head to prevent uncontrolled leakage of these fluids and / or the ingress of moisture into the free spaces.

For this purpose, the known Überwurfschraubelement an elongated shaft which protrudes in the fully screwed and tightened state from the input port of the channel to the outside and there carries an external thread on which a nut sits, by turning on a the input port of the channel on the Can be moved outside of the cylinder head surrounding, flat contact surface in the axial direction to or from this. Between the contact surface and the facing flat side of the nut an annular sealing disc is arranged on the shank of Überwurfschraubelements, which is pressed against the contact surface, when the nut is tightened when completely screwed Überwurf screw. Since the inner diameter of the sealing washer must be significantly larger than the outer diameter of the shaft of the union screw, so that the sealing washer when tightening the nut on the external thread of the shaft to the contact surface of the cylinder head can move, a further annular sealing element is required, which between the nut and the external thread of the shaft is arranged.

This known sealing arrangement has a number of disadvantages. It requires a pre-assembly of Überwurfschraubelements on which first the nut screwed together with the intermediate annular sealing element and then the sealing washer must be postponed before the assembly thus formed can be positioned on the fuel line. If the fuel line is then introduced into the channel of the cylinder head until the pressure nipple is seated on the counter-sealing surface of the nozzle holder and the coupling screw element is tightened, the nut seated on the shaft of the coupling screw element must additionally be tightened in order to achieve a tight closure of the inlet opening of the channel. In this case, provided between the nut and the external thread of the shaft sealing element complicates both the initial unscrewing of the nut on the shaft and their final tightening.

In contrast, the invention has the object, a connection arrangement of the type mentioned in such a way that with less and simpler parts and significantly simplified installation a sufficient requirements all sealing the fuel pipe receiving channel in the cylinder head can be achieved.

To solve this problem, the invention provides the features summarized in claim 1.

On the one hand, the entire sealing arrangement according to the invention is no longer disposed outside the channel but in its interior and forms part of the pressure transmission arrangement, which forwards the force exerted by the cap screwing element to the cap screwing element. In addition, their elastically deformable sealing elements are dimensioned so that they initially abut neither on the inner wall of the channel nor on the outer wall of the line during assembly of the arrangement. Rather, they are pressed to achieve the required tightness of these components only by the force exerted by the cap screw when screwing in the axial direction force causes axial compression of the sealing elements whereby they expand correspondingly far in the radial direction.

A significant advantage of this embodiment of the invention is that during assembly, no frictional forces between the sealing rings and the inner wall of the channel or the outer wall of the tubular fuel line must be overcome, because these parts come into contact only during the final tightening of Überwurfschraubelementes. As a result, the installation of such a connection arrangement is greatly facilitated.

The required for a good, high pressure-resistant seal compression of the sealing elements can thus be achieved solely by tightening the Überwurfschraubelementes. The use and operation of another element to be tightened, as it is the mother of the known arrangement, are not required.

Although the is DE 10 2007 047 518 A1 a connection arrangement for a fuel line with a sealing arrangement can be removed, which is arranged completely within the channel formed in the cylinder head. The pressure nipple of the actual fuel line is located outside this channel and to bridge the distance which is present between the channel inlet opening and arranged inside the cylinder head injection nozzle, the fuel line is extended by an array of hollow bodies, which includes a pressure pipe socket, which consists of a cylindrical Pipe and screwed with this another nipple. A cap screw, which can be screwed into the channel inlet opening, exerts in the tightened state on the outer end of the pressure pipe nozzle a force through which the pressure nipple located at its opposite end is pressed against a sealing surface of the injection nozzle. The pressure nipple of the fuel line must in turn be pressed by means of another Überwurfschraubelementes against a sealing surface of the cap screw whose inner cavity also forms part of the fuel flow path. A disadvantage of this known arrangement is the large number of individual elements forming the flow path of the fuel, all of which must be connected tightly to one another. A pressure tube, which coaxially surrounds this fuel line and transmits the pressure exerted by a screwed-on at the entrance of the channel Überwurfschraubelement force on the nipple is not present.

Furthermore, from the EP 2 354 529 A1 a connection arrangement for a tubular fuel line is known which extends through the channel formed in the cylinder head channel to the injection nozzle and rests with its pressure nipple on the counter-pressure surface. In this known arrangement, however, extends an axially directed pipe section of Überwurfschraubelementes so far into the channel head formed in the cylinder head, that it rests directly on the pressure receiving surface of the fuel line integrally formed nipple and adjust the sealing surface when tightening the Überwurfschraubelementes against the mating surface of the injector can. The sealing arrangement is formed by O-rings, which are arranged in corresponding grooves of the already mentioned and a further, coaxial screw-jacking element. In this known arrangement, the sealing arrangement forms no part of the pressure transmission device and its sealing elements are not subjected to elastic deformation when tightening the union screw.

A further advantage of positioning the sealing arrangement according to the invention is that the parts of the connection arrangement located outside the cylinder head in the assembled state have a very simple surface structure with a minimum of projections and recesses, so that the risk of permanent dirt accumulation in this area is reduced and Any necessary cleaning can be carried out easily and efficiently.

In a first embodiment, the entire sealing is carried out by means of a single, approximately hollow cylindrical sealing sleeve, which coaxially surrounds the tube of the fuel line and is arranged between the Überwurfschraubelement and the pressure tube so that it generated when screwing the former into the internal thread of the channel Transferring force to the pressure tube, which then passes on the pressure ring on the pressure nipple so that it is pressed with its pressure surface against the counter-pressure surface of the nozzle holder.

Alternatively, the hollow cylindrical, the pipe of the fuel pipe coaxially surrounding the sealing sleeve between denm inwardly, directed towards the nozzle holder axial end of the pressure tube and the pressure nipple of the fuel line can be arranged by the Andruckrohr when screwing the Überwurfschraubelements directly on the outwardly directed axial force exerted force and passes on the pressure nipple of the fuel line directly or via an interposed pressure ring.

Another possibility is to provide two such sealing sleeves, one of which is positioned between the union screw and the pressure tube and the other between the pressure tube and the pressure nipple. This is particularly important if the channel in the cylinder head, through which the pressure tube extends, is cut by a transverse bore bridged in the assembled state by the pressure tube, which connects the hollow spaces of the cylinder head filled with engine oil. The two sealing sleeves then prevent this engine oil can pass through the above-mentioned clearances between the outer surface of the fuel line and the pressure transmission assembly on the one hand and the pressure transmission assembly and the inner wall of the channel on the other hand to the outside or to the nozzle holder.

It should be emphasized that the use of two sealing sleeves in front of and behind the pressure tube can also be advantageous if no such oil-bearing transverse bore is present.

In each of these cases, at least one or each of the sealing sleeves in the transition region between its one axial end face and its outer peripheral wall has a first fold and in the transition region between its other axial end face and its inner peripheral wall has a second fold. In each of these folds, a sealing ring made of an elastomeric material is used, which protrudes initially over the respective front end in the axial direction, and whose radial thickness is dimensioned so that it does not so long on assembly on the inner wall of the channel or on the outer wall of the tubular fuel line comes to rest, as long as no axially directed force is exerted on him. If then during assembly the cap screw is screwed so far into the channel and tightened that the sealing sleeve is pressed by the inwardly facing end of the projecting into the channel pipe section against the nozzle holder remote from the front end of the pressure tube, in the two Folding seated sealing rings compressed in the axial direction and thereby expand simultaneously in the radial direction so far that they come to both the sealing sleeve and on the inner wall of the channel or the outer wall of the tubular fuel pipe to a tight fit and thereby the two mentioned above Close open spaces tightly.

The same advantage can be achieved with a further sealing arrangement according to the invention, which comprises at least one ring disk package, which consists of a rigid material of at least two circular annular disks concentrically surrounding the fuel line, one of which has an inner diameter slightly larger than the outer diameter the fuel line is, and carries on its outer circumference a sealing ring made of an elastomeric material, which initially protrudes in the axial direction over the two end faces of the annular disc and the radial thickness is dimensioned so that it initially not on assembly on the inner wall of the channel during assembly comes. Thus occur when inserting this seated on the fuel ring disc in the channel no significant frictional forces, which could complicate the assembly. The same applies to the second annular disc whose outer diameter is slightly smaller than the inner diameter of the channel and surrounding the fuel line in its central opening carries a sealing ring made of an elastomeric material, which initially protrudes in the axial direction over the two end faces of the annular disc and its radial Thickness is such that it initially does not come to the outer wall of the fuel line during assembly to the plant.

It should be expressly understood that advantageously also ring disk packages can be used which comprise more than two such annular disks, in which case an annular disk of the former type then alternately follows in the axial direction of an annular disk of the second type. Again, the two or more sealing rings are compressed in the axial direction and so enlarged at the same time in the radial direction so that the required sealing of the free spaces between the outer wall of the fuel line and the pressure tube on the one hand and the pressure tube and the inner wall of the channel on the other hand when final tightening the Überwurf screw is achieved.

It is also sufficient here to use only a single annular disc pact, which is arranged either between the union screw element and the pressure tube or between the pressure tube and the sealing nipple, as described above for the sealing sleeves according to the invention. However, it is also possible to use two sets of annular disks, one of which is positioned in the axial direction outside and the other in the axial direction inside the pressure tube. The latter is, but not limited to, particularly favorable again in those cases in which the channel formed in the cylinder head is cut by an oil-carrying bore.

In a further embodiment of a sealing arrangement positioned according to the invention, a sealing sleeve coaxially surrounding the fuel line has only one or more peripheral grooves in its outer cylindrical surface, in each of which a sealing ring made of an elastomeric material is inserted. The sealing of the free space between the fuel line and the pressure tube here assumes a hollow cylindrical sealing body made of an elastomeric material, which is inserted into the inwardly facing end portion of the inner bore of the Überwurfschraubelements having an enlarged inner diameter to provide space for the hollow cylindrical sealing body. This encloses the fuel line coaxially and comes to the assembly at her first not to the plant, so that during assembly no significant frictional forces must be overcome. The sealing body initially projects beyond the end face of the coupling screw element facing the sealing sleeve and is compressed in the axial direction when it is tightened by the end face of the sealing sleeve facing it. In this case, its wall thickness increases in the radial direction, so that it comes to the fuel line as well as on the inner wall of the extended end portion of the inner bore of the union screw good sealing to the plant. Also in this embodiment, all sealing effects are automatically achieved when tightening the Überwurfschraubelementes without additional labor or assembly steps are required.

The described different types of sealing devices (sealing sleeves and annular disc packs) can be combined with one another, in particular when one of them is positioned axially in front of and axially behind the pressure tube. However, it is also possible for two or more identical or different sealing devices to be used either only axially in front of or axially behind the pressure tube.

In the variants described hermetic sealing of the fuel pipe receiving channel is carried out against the outside world. However, it may be desirable to make the arrangement such that fluid entering the channel from the nozzle holder, for example fuel, can be removed, as in US Pat 3,845,748 is shown.

In order to realize such an arrangement, in a further variant of the connection arrangement according to the invention, the above-mentioned sealing sleeve and annular disks are omitted, so that during assembly the inwardly directed front end of the Überwurfschraubelements acts directly on the nozzle holder remote from the front end of the pressure tube. Again, in an end portion of the inner bore of the cap screw element, which has an enlarged inner diameter, an initially slightly projecting, hollow cylindrical sealing body made of an elastomeric material used, which comes to rest on the end face of the pressure tube facing it during assembly and when tightening the Überwurfschraubelements in the manner described above is compressed in the longitudinal direction, so that its wall thickness increases in the radial direction and it closes the free space between the outer surface of the fuel line and the inner wall of the pressure tube against the outside of the cylinder head. The sealing of the clearance between the outer surface of the pressure tube and the inner wall of the fuel line receiving channel is effected by a sealing ring inserted in a groove in the outer surface of the shank of the union screw of elastomeric material, in the assembled state in the axial direction on the input to the opening facing side of the internal thread of the channel is arranged. Between this sealing ring and the internal thread, which does not form a sealed closure, an annular free space is formed, from which a fluid penetrating from the nozzle holder into the channel can be sucked off.

These and other advantageous embodiments of a connection arrangement according to the invention are laid down in the subclaims.

Fig. 1

einen schematischen Schnitt durch eine nicht unter den Schutzumfang von Anspruch 1 fallende Anschlussanordnung, bei der die Dichtanordnung von einer zwischen dem Überwurfschraubelement und dem Andruckrohr angeordneten, die Kraftstoffleitung koaxial umgebenden Hülse und Dichtringen gebildet wird, die in umlaufende Nuten der Dichthülse eingesetzt sind,

Fig. 2

einen dem schematischen Schnitt der Fig. 1 entsprechenden Schnitt durch eine zweite, ebenfalls nicht unter den Schutzumfang von Anspruch 1 fallende Anschlussanordnung, bei welcher der Kanal im Zylinderkopf, durch den sich die Kraftstoffleitung und das sie konzentrisch umgebende Andruckrohr erstrecken, von einer Öl führenden Bohrung gekreuzt wird und zwei Dichthülsen zum Einsatz kommen, von denen die eine axial vor und die andere axial hinter dem Andruckrohr angeordnet ist,

Fig. 3

eine Detailansicht eines der Fig. 1 entsprechenden Schnitts durch eine noch nicht fertig zusammengebaute Ausführungsform einer erfindungsgemäßen Anschlussanordnung, bei der die Dichtanordnung von einer zwischen dem Überwurfschraubelement und dem Andruckrohr angeordneten, die Kraftstoffleitung koaxial umgebenden Dichthülse und Dichtringen gebildet wird, die in strinseitig offene Falze der Dichthülse eingesetzt sind,

Fig. 4

die Ausführungsform aus Fig. 3 im fertig montierten Zustand,

Fig. 5

eine Detailansicht eines der Fig. 1 entsprechenden Schnitts durch eine zweite, noch nicht fertig zusammengebaute Ausführungsform einer erfindungsgemäßen Anschlussanordnung, bei der die Dichtanordnung aus einem Ringscheibenpaket besteht, das drei die Kraftstoffleitung konzentrisch umgebende, zwischen dem Überwurfschraubelement und dem Andruckrohr axial hintereinander angeordnete Ringscheiben umfasst,

Fig. 6

die Ausführungsform aus Fig. 5 im fertig montierten Zustand,

Fig. 7

eine Detailansicht eines der Fig. 1 entsprechenden Schnitts durch eine dritte, noch nicht fertig zusammengebaute Ausführungsform einer erfindungsgemäßen Anschlussanordnung, bei der die Dichtanordnung von einer zwischen dem Überwurfschraubelement und dem Andruckrohr angeordneten, die Kraftstoffleitung koaxial umgebenden Hülse mit eingesetztem Dichtring und einem zylindrischen, die Kraftstoffleitung koaxial umgebenden Dichtelement gebildet wird, das in eine zum Düsenhalter hin gerichtete Erweiterung der Innenbohrung des Überwurfschraubelementes eingesetzt ist,

Fig. 8

die Ausführungsform aus Fig. 7 im fertig montierten Zustand, und

Fig. 9

einen der Fig. 1 entsprechenden Schnitt durch eine vierte Ausführungsform einer erfindungsgemäßen Anschlussanordnung im fertig zusammengebauten Zustand, bei der die Dichtanordnung von einem zylindrischen, die Kraftstoffleitung koaxial umgebenden Dichtelement, das in eine zum Düsenhalter hin gerichtete Erweiterung der Innenbohrung des Überwurfschraubelementes eingesetzt ist, und einem in eine in der Außenwand des Rohrabschnitts in Umfangsrichtung verlaufende Nut eingesetzten Dichtring gebildet wird.

The invention will be described below by means of embodiments with reference to the drawing; in this show:

Fig. 1

a schematic section through a not falling under the scope of claim 1 terminal assembly in which the sealing arrangement is arranged by a between the union screw and the pressure tube, the fuel line coaxially surrounding sleeve and sealing rings, which are inserted into circumferential grooves of the sealing sleeve,

Fig. 2

a the schematic section of the Fig. 1 corresponding section through a second, also not falling within the scope of claim 1 connection arrangement in which the channel in the cylinder head, through which the fuel line and the concentrically surrounding Andruckrohr extend, is crossed by an oil-carrying bore and two sealing sleeves are used of which one is arranged axially in front of and the other axially behind the pressure tube,

Fig. 3

a detailed view of one of Fig. 1 corresponding section through a not yet fully assembled embodiment of a connection arrangement according to the invention, in which the sealing arrangement is arranged by a between the union screw and the pressure tube, the fuel line coaxially surrounding the sealing sleeve and sealing rings, which are inserted into strinseitig open folds of the sealing sleeve,

Fig. 4

the embodiment of Fig. 3 in the assembled state,

Fig. 5

a detailed view of one of Fig. 1 corresponding section through a second, not yet fully assembled embodiment of a connection arrangement according to the invention, in which the sealing arrangement consists of a ring disk package, the three surrounding the fuel line concentrically surrounding, between the Überwurfschraubelement and the pressure tube axially successively arranged annular disks,

Fig. 6

the embodiment of Fig. 5 in the assembled state,

Fig. 7

a detailed view of one of Fig. 1 corresponding section through a third, not yet finished assembled embodiment of a connection arrangement according to the invention, in which the sealing arrangement of a arranged between the union screw and the pressure tube, the fuel line coaxially surrounding sleeve with inserted sealing ring and a cylindrical, the fuel line coaxially surrounding sealing element is formed inserted into a nozzle holder directed toward extension of the inner bore of the union screw element,

Fig. 8

the embodiment of Fig. 7 in the assembled state, and

Fig. 9

one of the Fig. 1 corresponding section through a fourth embodiment of a connection arrangement according to the invention in the assembled state, in which the sealing arrangement of a cylindrical, the fuel line coaxially surrounding sealing element, which is inserted into a nozzle holder directed toward extension of the inner bore of the union screw, and one in one in the outer wall the sealing ring formed in the circumferential direction of the pipe section is formed.

In the figures, the same or corresponding parts are provided with the same reference numerals. As used herein, positional references such as "left," "right," "top," "bottom," "vertical," "horizontal," or the like, all refer to the illustrations in the figures and are not limiting understand, because a connection arrangement according to the invention can take a variety of layers in the room.

In Fig. 1 is a schematic section through a part of a cylinder head 1 is shown having a vertically extending first bore into which from above a partially reproduced injector or nozzle holder 2 is inserted, in the known manner, a nozzle for injecting fuel into the Combustion chamber of the cylinder in question is added.

Perpendicular to the first bore extends through the cylinder head a further horizontal bore with an approximately circular cross-section which forms a channel 4 extending from an opening to the outside entrance opening 3 to the nozzle holder 2, in the left of a tube formed by Fuel line 5 is inserted, which serves to supply the injection nozzle arranged in the nozzle holder 2 under high pressure fuel. For this purpose, the fuel line 5 has at its end facing the nozzle holder 2, a duck nipple 6, for example, produced by upsetting, which with a sealing surface 8 formed on a nozzle holder 2, hollow conical mating surface 10 is applied, which surrounds the mouth of a further in the nozzle holder 2 fuel flow channel.

On its axially opposite side of the sealing surface 8, the pressure nipple 6 has a shoulder 11, which forms a pressure-receiving surface in that it protrudes radially beyond the outer surface of the fuel line 5, to which a contact force is transmitted by means of a pressure transmission arrangement coaxially surrounding the fuel line 5, which is produced by a screw-threaded element 15 formed by a pressure screw being screwed into an internal thread 16 of a section of the channel 4 directly adjoining the inlet opening 3, such that a pipe section 17 of the coupling screw element 15 protruding into the channel 4 first engages it facing front end of the pressure transfer assembly comes to rest and then shifts in the direction of the nozzle holder 2 out.

In the in the Fig. 1 shown, ready assembled embodiment, the pressure transmission assembly consists of a in the mounted state on the pressure receiving surface of the shoulder 11 supporting, substantially hollow cylindrical pressure ring 18, a subsequent thereto hollow cylindrical pressure tube 19, which bridges most of the length of the channel 4, and a hollow cylindrical sealing sleeve 20 against which abuts the inner end face of the pipe section 17 of the union screw 15.

In the production of the fuel line 5, the pressure nipple 6 is first upset on the pipe forming it, whereupon the individual parts of the pressure transmission arrangement are then pushed from the not yet deformed end to which then in general also a pressure or sealing nipple is upset.

To allow the pushing of the pressure ring 18 and the pressure tube 19 to the fuel line 5, the inner diameter of each of these components must be slightly larger than the outer diameter of the fuel line 5, whereby between these components a continuous, hollow cylindrical space 21 is present, which is a very owns small clear width and because of that for the Fig.1 selected scale in this not directly visible but only indicated by the end point of the reference line.

Furthermore, the inner diameter of the channel 4 must be greater than the outer diameter of the pressure ring 18 and the pressure tube 19, so that the fuel line surrounded by these components can be inserted into the channel 4. The resulting hollow cylindrical space 22 must be much larger than the space 21 to allow the assembly.

The two mentioned clearances 21, 22 must be sealed to the outside, to prevent both the leakage of leakage fuel and / or engine oil, which could penetrate into it from the engine, and on the other hand, the ingress of moisture from the outside space.

At the in Fig. 1 As shown embodiment, the sealing of the two free spaces 21, 22 by means of the aforementioned sealing sleeve 20, whose inner and outer diameter are matched to the outer diameter of the tubular fuel line 5 and the inner diameter of the channel 4, that insertion is just possible. The actual sealing function is adopted by three sealing rings 24, 25 and 26, which consist of an elastic material resistant to engine oil and fuel and of which the former in a in the wall of the sealing sleeve 20 approximately in the middle of its axial length from the outside her incorporated, is arranged around the circumference extending groove, while the other two sit in grooves which are incorporated into the wall of the sealing sleeve 20 from the inside with approximately equal axial distances from the center of the axial length of the sealing sleeve 20.

Alternatively, in the outside of the wall of the sealing sleeve 20, two or more grooves with sealing elements arranged in them and only one or more than two grooves with sealing elements arranged therein may be provided in the inside of the wall of the sealing sleeve 20.

It is essential that all sealing elements in the mounted state so abut against the inner wall of the channel 4 and the outer wall of the fuel line 5, that neither moisture from the outside in or oil or fuel can pass from the inside out.

In Fig. 2 is one of the fig1 , corresponding section through a cylinder head 1, which encloses a valve chamber 7, from which a motor oil leading, the channel 4 intersecting transverse bore 9 leads to another (not shown) cavity of the cylinder head 1. So that from this transverse bore engine oil through the free spaces 21, 22 can neither reach the nozzle holder 2 nor the outside of the cylinder head 1, the sealing arrangement according to the invention comprises two sealing sleeves 20, 20 'of the associated Fig. 1 described type, one of which is arranged between the inwardly facing end face of the union screw 15 and the outwardly directed axial end face of the pressure tube 19 and the other between the inner, pointing to the nozzle holder 1 front end of the pressure tube 19 and the pressure ring 18. Both sealing sleeves 20, 20 'carry sealing rings 24, 25, 26 and 24', 25 ', 26' in the same manner as above in connection with Fig. 1 has been described. The pressure generated when tightening the Überwurfschraubelementes 15 is thus here of the inner end face on the outer sealing sleeve 20, from there to the pressure tube 19, of this on the inner sealing sleeve 20 ', of this on the pressure ring 18 and of this finally on the pressure nipple 6 of the fuel line 5 transmitted, the sealing surface 8 is thus pressed in sealing manner against the counter-sealing surface 10 of the nozzle holder 2.

In Fig. 3 is only a part of one of the Fig. 1 reproduced similar section through a further embodiment, in which the union screw 15 is not yet completely screwed into the internal thread 16 of the channel 4 and therefore not with its inner end face on the tubular fuel pipe 5 concentrically surrounding sealing sleeve 28 is applied, here in principle the same function has like the sealing sleeve 20 from in conjunction with Fig. 1 described embodiment. In contrast to this, but it has no serving to accommodate sealing rings, circumferential grooves in its inner or outer surface but two folds, one of which in the transition region between the outer peripheral surface and the pressure tube 19 facing end face of the sealing sleeve 28 and the other is formed in the transition region between the inner peripheral surface and the Überwurfschraubelement facing end face of the sealing sleeve 28. In each of these folds, a sealing ring 30 and 31 is inserted, whose axial length is dimensioned so that it is in the in Fig. 3 shown, not yet assembled state protrudes out of its associated fold out over the relevant end face of the sealing sleeve 28 in the axial direction. Furthermore, the sealing rings 30, 31 each have a radial thickness or wall thickness which is not greater than the radial depth of the respective fold, so that they in the in Fig. 3 shown rest neither on the inner wall of the channel 4 nor on the outer wall of the conduit 5, whereby the assembly is greatly facilitated, since no special frictional forces must be overcome.

Will then, as in Fig. 4 shown, the Überwurf screw 15 completely screwed into the internal thread 16 and tightened, the inner end of the pipe section 17 moves so far into the channel 4, that it comes to rest on the front end of the sealing sleeve 28 and this so far in the direction of the nozzle holder 2 (see Fig. 1 ) shifts that the inner end face of the sealing sleeve 28 comes to rest on the outwardly directed front end of the pressure tube 19, so that in this way (as in Fig. 1 shown) by the force generated when screwing the Überwurf screw member 15 via the pressure ring 18 and the shoulder 11, the sealing surface 8 of the pressure nipple 6 is pressed in a sealed manner against the counter-sealing surface 10 of the nozzle holder. At the same time, the two sealing rings 30, 31 are brought together in the axial direction, so that they expand so much in the radial direction that they between the sealing sleeve 28 on the one hand and the inner wall of the channel 4 and the outer wall of the fuel line 5 on the other hand, the desired tight closure of the free spaces 21 or 22 cause.

In the in the FIGS. 5 and 6 In the embodiment shown, the sealing arrangement positioned between the union screw element 15 and the pressure tube 19 comprises an annular disc package consisting of three substantially non-deformable material, for example steel, annular discs 34, 35, 36, consisting of a fixed axial force due to the tightening screw element 15 being tightened. which are arranged one behind the other in the axial direction and surround the fuel line 5 concentrically. The two axially outer annular discs 34, 36 have an inner diameter which is slightly larger than the outer diameter of the fuel line 5, so that they can be easily slid onto them during assembly. On the outer circumference of each of these two annular discs 34, 36, a sealing ring 37, 39 is mounted, whose axial length is greater than that of the associated annular disc 34 and 36, so that it in the in Fig. 5 shown state in which the union screw 15 is not screwed far enough into the internal thread 16 of the channel 4, beyond the end faces in the axial direction also stands. The outer diameter of each of these sealing rings 37, 39 is initially, ie slightly smaller than without axial compression the inner diameter of the channel 4, so that when introducing the provided with these sealing rings 37, 38 annular discs 34, 36 in the channel 4 no significant frictional forces must be overcome.

The third, between the other two arranged annular disc 35 has an outer diameter which is slightly smaller than the inner diameter of the channel 4 and carries a seal inserted into its central opening 38, which in the uncompressed state (see Fig. 5 ) protrudes in the axial direction over its end faces and has an inner diameter which is greater than the outer diameter of the fuel line 5. By this dimensioning is achieved that even when mounting the annular disc 35 no significant frictional forces occur.

Only when, as in Fig. 6 shown, the union screw 15 is completely screwed in and tightened, the sealing rings 37, 38 and 39 are compressed by the axial force exerted between the end faces of the pipe section 17, the annular discs 34, 35 and 36 and the pressure tube 19 in the axial direction, causing them expand in the radial direction and press against the inner wall of the channel 4 and the outer wall of the fuel line 5 so that the desired tight closure of the free spaces 21 and 22 is achieved.

As an alternative to the advantageous embodiment just described, the sealing arrangement can also comprise only two or more than three annular disks, wherein then always the annular disks 34 and 36 on the one hand and the annular disk 35 on the other hand corresponding annular disks are arranged alternately.

In the in the FIGS. 7 and 8 embodiment shown is similar to in Fig.1 a sealing sleeve 40 concentrically surrounding the tubular fuel line 5 and forming part of the pressure transfer arrangement is provided in the area between the end of the pipe section 17 of the screw connection element 15 facing away from the nozzle holder 2 and the end of the pressure tube 19 facing away from the nozzle holder 2, but this sealing sleeve 40 only has one single, formed by a sealing ring 41 sealing element, which is arranged in the same manner as the outer sealing ring 24 of the associated Fig. 1 described example; Thus, it causes only a seal between the inner wall of the channel 4 and the outer wall of the pressure tube 19 existing free space 22nd

The sealing of the free space 21 between the outer wall of the fuel line 5 and the inner wall of the pressure tube 19 is effected here by a hollow cylindrical sealing body 43 made of an elastomeric, resistant to engine oil and / or fuel material in an extension of the pipe section 17 of the union screw element 15 passing hole is accommodated and the fuel line 5 coaxially encloses. The axial length of this sealing body 43 is slightly larger than that of the extension of the bore of the pipe section 17, so that it out of this, as in Fig. 6 shown projects slightly in the axial direction as long as the union screw 15 is not completely screwed and tightened in the channel 4 during assembly of the assembly.

When final tightening the Überwurfschraubelements 15 then comes the protruding end of the sealing body 43 at the opposite end edge of the sealing sleeve 40 to the system and is compressed in the course of tightening by the opposing force, which is applied to the mating surface 10 of the nozzle holder 2 pressure nipple 6 via the pressure ring 18 exerts on the pressure tube 19. By this compression, the radial thickness of the sealing body 43 increases, so that it bears against the inside of the extension of the bore of the pipe section 17, on the fuel line 4 and on the end face of the sealing sleeve 40 facing it and the free space 21 between the outer wall of the fuel line 5 and the inner wall of the pressure tube 19 closes tightly against the outer region, as in Fig. 8 shown.

Again, the sealing sleeve 40 may wear more than a sealing ring on its outer side.

In the embodiment of the Fig. 9 is not the tubular fuel line 5 coaxially surrounding, provided between the pipe section 17 of the union screw 15 and the Anduckrohr 19 sealing sleeve. The pressure tube 19 is formed correspondingly longer, so that when assembling a sealing body 45 which is formed and arranged as the sealing body 43 in the FIGS. 7 and 8 , when tightening the cap screw 15 instead of the axially outwardly directed end of a sealing sleeve of the corresponding end of the pressure tube 19 is compressed in the same manner as described above, whereby a tight closure of the space 21 between the outer wall of the fuel line 5 and Inner wall of the pressure tube 19 takes place with respect to the outer region of the cylinder head 1.

Furthermore, the internal thread 16 of the channel 4, in which the Überwurfschraubelement 15 is screwed during assembly, arranged in the axial direction further displaced towards the nozzle holder 2 and the channel 4 has directly to its inlet opening 3 then a hollow cylindrical sealing portion 47, which has a larger inner diameter as the adjoining him internal thread 16 and the underlying portion of the channel 4, which surrounds the pressure tube 19, so that at the transition from the sealing region 47 to the region of the internal thread 16, a radially extending, circumferential shoulder 48 is formed.

The union screw element 15 has a shank portion 50, to which the pipe section 17 to be screwed into the internal thread 16 of the channel 4 adjoins in the axial direction. This shank portion 50 has a larger outer diameter than the pipe section 17, so that between these two sections and on Überwurfschraubelement 15 extending in the radial direction, circumferential shoulder 51 is present.

The axial lengths of the shank portion 50 of the union screw element 15 and of the sealing region 47 of the channel 4 adjoining the inlet opening 3 are coordinated with one another such that the shoulder 51 in the fully assembled state, in which the Überwurfschraubelement 15 is tightened in the axial direction closer to the input port 3, as the shoulder 48, so that between these two shoulders 51, 48 remains a clearance 53, which on the no tight seal forming screw between the cap screw 15 and the internal thread 16 fluidly communicates with the clearance 22 between the inner wall of the channel 4 and the outer wall of the pressure tube 19, so that existing there engine oil or fuel can pass into the space 53.

So that it does not come out of this uncontrolled outward, a circumferentially extending groove is provided in the outer wall of the shank portion 50 of the Überwurfschraubelements 15, in which a sealing ring 54 is seated fixed in the assembled state on the inner wall of the sealing region 47 of the channel 4 rests and ensures a tight seal against the outside. From the free space 53 between the shoulders 48 and 51, a drainage channel can lead away, over which optionally a controlled removal and return of a fluid (engine oil or fuel) that has entered the free spaces 22 and 53 can take place.

Thus, as can be seen from the foregoing description, in each of the embodiments, all the sealing elements needed to seal the clearances 21 and 22 against the exterior are within the channel 4 and no additional screwing elements are required to achieve compression of these sealing elements which ensures a good seal even at high pressures.

Claims (12)

1. A connecting arrangement for a tubular fuel line (5) which coming from the exterior extends through a passage (4) in a cylinder head (1) to a nozzle holder (2) of an injection nozzle to feed fuel thereto, wherein at its front end towards the nozzle holder (2) the fuel line (5) has a pressure nipple (6) which on its front side has a sealing surface (8) and on its rear side a pressure receiving surface, wherein the connecting arrangement includes the following:

   a threaded cap element (15) which coaxially surrounds the fuel line (5) and is screwed in the region of the inlet opening (3) of the passage (4) so that it projects with an axially directed tube portion (17) into the passage (4),

   a pressure transmission arrangement which is arranged in the interior of the passage (4), coaxially surrounds the fuel line (5) and comprises a pressing tube (19) coaxially surrounding the fuel line (5), on the axially outwardly end of which the axially inwardly directed end of the tube portion (17) of the threaded cap element (15) in the tightened condition exerts a force which is directed axially towards the nozzle holder (2) said force being transmitted to the pressure receiving surface of the pressure nipple (6) to press the sealing surface (8) thereof against a counterpart sealing surface (10) which is provided on the nozzle holder (2) and which surrounds the mouth opening of a fuel flow passage leading further in the nozzle holder (2), and

   a sealing arrangement (28; 34, 35, 36; 40, 45) which seals off a first open space (21) between the outside wall of the fuel line (5) and the inside wall of the pressure transmission arrangement and a second open space (22) between the outside wall of the pressure transmission arrangement and the inside wall of the passage (4) towards the exterior of the cylinder head (1),

   characterised in that the sealing arrangement (28; 34, 35, 36; 40, 45) which is positioned completely in the interior of the passage (4) forms part of the pressure transmission arrangement in such a way that, by the force which is exerted in axial direction by the threaded cap element (15) upon being screwed in, at least one of the sealing bodies (30; 31; 37; 38; 39: 43; 45) thereof is by an axial compression expanded in radial direction to an extent that it bears sealingly against the inside wall of passage (4) or the outside wall of line (5) after the threaded cap element (15) has been tightened.
2. A connecting arrangement as set forth in claim 1 characterised in that the sealing arrangement includes at least one sealing sleeve (28) which coaxially surrounds the fuel line (5) and which is arranged between the inwardly directed end of the tube portion (17) of the threaded cap element (15) and the end of the pressing tube (19) that is remote from the nozzle holder (2), said sealing sleeve transmitting to the pressing tube (19) the force which is exerted by the threaded cap element (15) upon being screwed in, to the pressing tube (19) the end of which being directed towards the nozzle holder (2) which transmits said force directly or by means of a pressure ring coaxially surrounding the fuel line (5) to the pressure nipple (6) of the fuel line (5).
3. A connecting arrangement as set forth in claim 1 characterised in that the sealing arrangement includes at least one sealing sleeve which coaxially surrounds the fuel line (5) and is arranged between the inwardly, towards the nozzle holder directed end of the pressing tube (19) coaxially surrounding the fuel line (5), and the pressure nipple (6) of the fuel line (5), said sealing sleeve transmitting the force which is exerted by the threaded cap element (15) upon being screwed in to said pressing tube (19) and from this pressing tube to said sealing sleeve directly or via a pressure ring coaxially surrounding the fuel line (5) to the pressure nipple (6) of the fuel line (5).
4. A connecting arrangement as set forth in claims 2 or 3 characterised in that the sealing sleeve (28) comprises a notch which is disposed in the transitional region between the one end and the outer peripheral surface thereof and into which is fitted a sealing ring (30') which prior to the tightening of the threaded cap element (15) projects in the axial direction beyond the respective end face of the sealing sleeve (28) and does not extend in the radial direction up to the inside wall of the passage (4), and that the sealing sleeve (28) further comprises a notch which is disposed in the transitional region between the other end and the inner peripheral surface thereof and into which is fitted a sealing ring (31') which prior to the tightening of the threaded cap element (15) projects in the axial direction beyond the end face in question of the sealing sleeve (28) and does not extend in the radial direction up to the outside wall of the fuel line (5), and in that after tightening of the threaded cap element (15) the two sealing rings (30, 31) by virtue of axial compression are expanded in the radial direction to such an extent that they bear sealingly against the inside wall of the passage (4) and the outside wall of the fuel line (5) respectively.
5. A connecting arrangement as set forth in claim 1 characterised in that the sealing arrangement includes at least one set of circular annular discs (34, 35, 36) comprising at least two circular annular discs which concentrically surround the fuel line (5) and a first one (34) of which has an inside diameter somewhat larger than the outside diameter of the fuel line (5) and at least a second one (35) of which has an outside diameter somewhat smaller than the inside diameter of the passage (4), and in that the at least one first annular disc (34) carries on its outer periphery a sealing ring (37) which projects in the axial direction beyond the two end faces of the disc and whose outside diameter prior to the tightening of the threaded cap element (15) is somewhat smaller than the inside diameter of the passage (4), and in that the at least one second annular disc (35) in its central opening carries a sealing ring (38) which projects in the axial direction beyond the two end faces of said disc and whose inside diameter prior to the tightening of the threaded cap element (15) is somewhat larger than the outside diameter of the fuel line (5), and in that the two sealing rings (37, 38) after the tightening of the threaded cap element (15) by virtue of axial compression are expanded in the radial direction to such an extent that they bear sealingly against the inside wall of the passage (4) and the outside wall of the line (5), respectively.
6. A connecting arrangement as set forth in claim 5 characterised in that the at least one set of circular annular discs (32) is arranged between the inwardly directed end of the tube portion (17) of the threaded cap element (15) and the end of the pressing tube (19) that is remote from the nozzle holder (2), said pressing tube (19) coaxially surrounding the fuel line (5).
7. A connecting arrangement as set forth in claim 5 characterised in that the at least one set of circular annular discs is arranged between the inwardly directed end of the of the pressing tube (19) coaxially surrounding the fuel line (5) and the pressure nipple (6) of the fuel line (5)
8. A connecting arrangement as set forth in claim 5 characterised in that it comprises two sets of circular annular discs one of these sets being arranged between the inwardly directed end of the tube portion (17) of the threaded cap element (15) and the end of the pressing tube (19) that is remote from the nozzle holder (2), said pressing tube coaxially surrounding the fuel line (5), whereas the other one of these sets is arranged between the inwardly directed end of the pressing tube (19) coaxially surrounding the fuel line (5) and the pressure nipple (6) of the fuel line (5).
9. A connecting arrangement as set forth in claim 1 characterised in that the continuous inner bore of the threaded cap element (15) has, in the region of the tube portion (17), an enlargement which is open towards the nozzle holder (2) and into which is fitted a hollow-cylindrical sealing body (43) whose inside diameter is somewhat larger than the outside diameter of the fuel line (5) and which, prior to the tightening of the threaded cap element (15), projects in the axial direction out of the tube portion (17) and which, after the tightening of the threaded cap element (15), by virtue of axial compression is expanded in the radial direction to such an extent that it bears sealingly against the inside wall of the enlargement of the inner bore of the threaded cap element (15) and against the outside wall of the fuel line (5).
10. A connecting arrangement as set forth in claim 9 characterised in that the threaded cap element (15) has a peripherally extending groove on the outside surface of a shaft portion (50) projecting into the passage (4), a sealing ring (54) bearing sealingly against the inside wall of the passage being fitted in said peripherally extending groove.
11. A connecting arrangement as set forth in one of the preceding claims characterised in that the threaded cap element (15) is in the form of a cap screw and is screwed into a female screwthread (16) formed in the region of the inlet opening (3) of the passage (4) in the inside wall of the latter.
12. A connecting arrangement as set forth in one of the preceding claims characterised in that provided between the end of the pressing tube (19), that is towards the nozzle holder (2), and the pressure receiving surface of the pressure nipple (6), there is a pressure ring (18) which coaxially surrounds the fuel line (5) and which transmits from the pressing tube (19) to the pressure nipple (6) the axially directed force produced upon tightening of the threaded cap element (15).

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