EP0923673A1

EP0923673A1 - Coupling for fuel lines or the like

Info

Publication number: EP0923673A1
Application number: EP98906832A
Authority: EP
Inventors: Dewey Mckinley Sims; Gary Roy Paige
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1997-04-01
Filing date: 1998-01-22
Publication date: 1999-06-23
Also published as: WO1998044257A1; DE19713446A1; JP2000512361A

Abstract

The invention relates to a coupling for fuel lines or the like. The insert section (4) of a first coupling section (1) which is connected to a first fuel line is axially inserted into a socket section (11) of a second coupling section (2) which is connected to a second fuel line. Both liquid-tight coupling sections (1, 2) which are inserted into each other form a fuel passage duct and are connected to each other by means of a holding device which comprises at least one pair of blocking elements (19, 20, 21, 22) that can be axially inserted into each other when said coupling sections are joined and which are respectively and eccentrically arranged on one coupling section (1, 2) in relation to the passage duct. When the liquid-tight coupling sections (1, 2) are inserted into each other, sufficient play is provided to limit mutual swivelling of both coupling sections (1, 2) to the rotational path defined by said play. The holding device also comprises at least two locking elements (18, 23, 24) engaging with each other for mutual retention of both coupling sections (1, 2) when said liquid-tight coupling elements (1, 2) are joined to each other and when said blocking elements (19, 20, 21, 22) are inserted into each other.

Description

Title: Coupling for fuel lines or the like

Technical field:

The invention relates to a coupling for fuel lines or the like, in which a first coupling part connected to a first fuel line, which is provided with an insertion section and an internal flow channel for the fuel opening into the insertion section, with its insertion section into an insertion section second coupling part is used, which is connected to a second fuel line and is provided with an inner flow channel for the fuel, which opens into the plug-on section, the two fluid-tightly inserted coupling parts, which form a through-channel for the fuel, are connected to one another by a holding device.

State of the art:

Such couplings are used according to WO 90/03510 within a fuel supply device of a fuel injection system of a two-row internal combustion engine. The couplings in each case connect one end of a fuel line, which runs as a rigid tube and runs transversely to the cylinder rows of the internal combustion engine, to one end of the two fuel distribution lines, which run parallel to the cylinder rows and each of which accommodates the fuel injection valves of a row of cylinders of the internal combustion engine arranged in a row. With each coupling, the tube end of the rigid cross tube provided with an outwardly projecting annular bead forms the plug-in section of the first coupling part and one the plug-in section receiving sleeve at one end of the respective fuel distribution line, the push-on section of the second coupling part. A sealing ring sits on the pipe end of the insertion section and seals the axial through channel of the coupling to the outside. The two coupling parts, which are inserted into one another in a fluid-tight manner, are rotatably connected to one another by a holding device. This consists of the annular bead of the plug-in section arranged inside the sleeve of the push-on section and of an outer stop which is attached behind the annular bead after it has been inserted into the sleeve. This stop can be formed by a cylindrical collar of the sleeve, which is bent inward behind the annular bead, or by a holder placed behind the annular bead on the sleeve, from which the stop projects into the interior of the sleeve.

The known coupling allows the rigid cross tube to be rotated indefinitely relative to the respective fuel distribution line. As a result, when a fuel supply device is installed on an internal combustion engine, the two fuel distribution lines, each connected to the cross tube via such a coupling, can be aligned with their fuel injection valves to the respective row of cylinders of the internal combustion engine. The unlimited rotatability between cross tube and fuel distribution line also has disadvantages.

Because of the unlimited rotatability of the known coupling, the spatial alignment produced when the fuel supply device is assembled between the cross tube and the respective fuel distribution line is not retained until the fuel supply device is attached to the internal combustion engine. Even small external forces, such as when laying down the assembled fuel supply device on a surface or as during the Transporting the fuel supply device from the place of its assembly to the place of its attachment to the internal combustion engine in question or how it occurs inevitably during the testing of the fuel supply device leads to the fuel distribution lines and the cross tube inadvertently rotating with respect to one another and each time changing their mutual spatial orientation. Before the fuel supply device is attached to the internal combustion engine, the spatial alignment of the parts that can be rotated relative to one another must therefore be checked and an incorrect alignment corrected before the attachment or during the attachment of the fuel supply device to the internal combustion engine by additional straightening work. For this purpose, the mutually rotatable parts must be handled separately and brought individually into the respective intended position. The unlimited rotatability of the coupling connecting the cross tube to the respective fuel distribution line therefore makes mounting the fuel supply device on the internal combustion engine considerably more difficult and requires additional checking and straightening work.

WO 90/03510 shows variously designed couplings, with some of the couplings either not providing sufficient mechanical strength to prevent the plug-in section from being torn out of the plug-on section, or a large number of complex parts which require increased assembly effort.

Summary of the Invention:

The object of the invention is to eliminate these disadvantages and to provide a coupling for fuel lines or the like which, in the case of coupling parts which are inserted in a fluid-tight manner, permits mutual alignment of the two coupling parts and at the same time limits their extent. This is achieved according to the invention by a coupling for fuel lines or the like, in which a first coupling part, which is connected to a first fuel line and is provided with an insertion section and an inner flow channel for the fuel opening into the insertion section, with its insertion section into an attachment - Section of a second coupling part is used, which is connected to a second fuel line and is provided with an internal flow channel for the fuel opening into the plug-on section, the two fluid-tightly inserted and a through-channel for the fuel-forming coupling parts being connected to one another by a holding device. According to the invention, this coupling is characterized in that the holding device comprises at least one pair of locking elements which can be pushed into one another when the two coupling parts are inserted into one another and are each arranged on a coupling part, between which, in the case of coupling parts which are inserted into one another in a fluid-tight manner, a movement play limited to a predefinable angle of rotation is provided and that the holding device comprises at least two locking elements which, in the case of coupling parts which are inserted into one another in a fluid-tight manner and locking elements which are pushed into one another, can be brought into engagement with one another in order to hold the two coupling parts together.

This configuration limits the extent of the possible mutual alignment of the two nested coupling parts, which form an outwardly sealed passage for the fuel, to a predetermined size. This is determined by the freedom of movement existing between the locking elements, which is composed of the respectively desired twisting path of the two coupling parts and the manufacturing-related manufacturing tolerances of the two coupling parts or their locking elements. That remains when the coupling parts are inserted into each other in a fluid-tight manner permanent peripheral movement between the locking elements can be matched to the desired relative rotation of the two coupling parts. Any twisting of a coupling part in relation to the other coupling part beyond the movement play of the locking elements is effectively excluded.

The coupling according to the invention establishes a fluid-tight connection free of mechanical stresses between the two fuel lines. This is advantageous when connecting a fuel line formed by a metal pipe to a fuel line made from plastic. The coupling part connected to the metal tube can also consist of metal and the coupling part connected to the plastic line can also consist of plastic. In such a coupling, the metal locking elements of one coupling part engage with play in the plastic locking elements of the other coupling part.

In the case of fuel supply devices of double-row internal combustion engines, the use of couplings according to the invention as a mechanical connection between the distribution lines parallel to the cylinder rows and the connecting line running transversely to the cylinder rows limits the size of the alignment errors which occur when assembling the individual assemblies of the fuel supply device to a predetermined level. Rough handling of the assembled fuel supply device provided with couplings according to the invention during storage, transport and testing does not lead to an increase in the alignment errors of the individual components of the fuel supply device. As a result, the insertion of the fuel injectors carried by the fuel distribution lines into the openings of the internal combustion engine provided for them during the assembly of the power— Substance feed device on the internal combustion engine significantly simplified. A check or correction of the alignment of the fuel injection valves of the fuel supply device immediately before they are installed in the internal combustion engine can be omitted.

According to a further feature of the invention, it can be provided that a first locking element, which is arranged on the first coupling part, together with a second locking element, which is arranged on the second coupling part and is aligned with the first locking element, forms a pair of locking elements.

The first locking element can be formed on the first coupling part on a locking portion downstream of the insertion section and the second locking element on the push-on portion of the second coupling part. The locking section of the first coupling part, which is spatially separated from the insertion section, can protrude radially beyond the plug-on section of the second coupling part and axially overlap it on its outside.

According to a further feature of the invention, it can be provided that an axial recess is provided as the first locking element, which is arranged on the first coupling part, and that a projection is provided as the second locking element, which is arranged on the second coupling part, the in the circumferential direction measured width of the axial recess is greater than that of the projection.

According to a further feature of the invention, it can be provided that the axial recess is designed as an outwardly open longitudinal channel of the first coupling part, in which a finger-shaped projection is received as a second locking element in the case of coupling parts which are inserted into one another in a fluid-tight manner. According to a further feature of the invention, it can be provided that the axial recess is designed as an axial passage opening of the first coupling part, which, in the case of coupling parts which are inserted into one another in a fluid-tight manner, is penetrated by a finger-shaped projection as the second locking element.

According to a further feature of the invention it can be provided that an axial longitudinal rib of the first coupling part is provided as the first locking element and an axial recess of the second coupling part is provided as the second locking element, the width of the longitudinal rib being smaller than that of the axial recess.

According to a further feature of the invention, it can be provided that at least two pairs of locking elements are provided, which are diametrically opposite one another with respect to the through-channel.

According to a further feature of the invention, it can be provided that several pairs of locking elements are arranged distributed uniformly over the circumference.

According to a further feature of the invention, it can be provided that the holding device for mutually locking the two coupling parts comprises at least two locking elements which can be axially pushed into one another when the two coupling parts are inserted into one another and are each arranged on a coupling part, on the outer sides of which circumferential grooves are provided in the case of coupling parts which are inserted into one another in a fluid-tight manner, align with one another and form a locking groove into which a locking element is inserted.

According to a further feature of the invention, it can be provided that the coupling parts, which are inserted into one another in a fluid-tight manner, engage in one another with a peripheral movement play. Fenden locking elements are also designed as locking elements that have the circumferential grooves for the locking element on their outer sides.

According to a further feature of the invention, it can be provided that the locking element is designed as a metal ring which is bent in the locking groove from a metal bracket.

According to a further feature of the invention it can be provided that for the mutual locking of the two coupling parts on the first coupling part, a locking section is provided which, when the coupling parts are inserted in a fluid-tight manner, engages over the free end of the plug-on section of the second coupling part and contains at least one permanently deformable locking element which can be brought into engagement with a recess arranged on the outside of the plug-on section of the second coupling part.

According to a further feature of the invention, it can be provided that the locking section has a plurality of permanently deformable locking elements which are arranged uniformly distributed around the plug-on section when the coupling parts are inserted into one another in a fluid-tight manner and can be brought into engagement with a circumferential groove arranged on the outside of the plug-on section.

According to a further feature of the invention, it can be provided that a locking element is provided on a coupling part, which engages elastically when the coupling parts are inserted into one another in a boundary wall provided on the other coupling part.

The invention is explained in more detail below with the aid of some exemplary embodiments with reference to the drawings. Brief description of the drawings:

1 shows a first embodiment of a coupling for connecting two fuel lines, the two coupling parts being shown axially pulled apart,

2 shows an oblique view of a second embodiment of a coupling for connecting two fuel lines, the two coupling parts being shown axially pulled apart,

3 shows an oblique view of the coupling of FIG. 2 with coupling parts inserted into one another and locked by a metal ring,

Fig. 4 shows schematically the locking of the coupling of FIGS. 2 and 3 with a metal bracket provided with a curved back and straight legs, before locking with straight legs inserted into the circumferential groove of the holding device (FIG. 4a) and after locking with in the circumferential groove to a ring bent metal bracket (Fig. 4b),

FIG. 5 shows, similar to FIG. 4, the locking of the coupling of FIG. 2 with a metal bracket provided with a straight back and straight legs, before locking with straight legs inserted into the circumferential groove (FIG. 5a) and after locking with in the circumferential groove curved legs (Fig. 5b),

FIG. 6 shows, similar to FIG. 5, the locking of the coupling of FIG. 2 with a metal bracket provided with a straight back and straight legs, before locking with straight legs inserted into the circumferential groove (FIG. 6a) and after locking with back curved in the circumferential groove and limbs curved in the circumferential groove (FIG. 6b), 7 shows a further embodiment of a coupling for connecting two fuel lines, the two coupling parts being shown axially apart from one another in FIGS. 7a and 7b,

8 shows an axial longitudinal section through the cup-shaped connection head of the first coupling part of the coupling of FIG. 7,

9 shows an end view of FIG. 8,

10 shows an end view of the plug-on section of the second coupling part of the coupling of FIG. 7,

FIG. 11 shows an axial longitudinal section through the coupling of FIG. 7 with coupling parts inserted into one another and locked together by locking elements, and

12 shows fuel lines connected to clutches constructed according to the invention.

Description of exemplary embodiments:

Fig. 1 shows the better clarity greatly simplified a first embodiment of a clutch that connects two fuel lines mechanically limited fluid and fluid-tight together and can be designed so that after assembly of the clutch, the two fuel lines are so firmly connected that they only can be uncoupled with a tool. FIGS. 2 to 6 show an example of a second, preferably selected embodiment of the coupling, which differs from the embodiment of FIG. 1 essentially only in the number of projections 20, 22 and recesses provided. Therefore, both embodiments are explained together below. The coupling comprises two coupling parts 1 and 2 which can be plugged into one another in a fluid-tight manner and which, when inserted into one another, form a tight connection between two fuel lines 6, 13 with a central through-channel for the fuel. The coupling comprises a mechanically lockable holding device which, in its locked state, connects the two nested coupling parts 1 and 2 to one another and at the same time allows a limited axial relative movement of the two coupling parts 1, 2 without impairing the leak-free, tight connection of the two fuel lines 6, 13 . The coupling is essentially designed so that the two coupling parts 1, 2 can be rotated relative to each other by a limited angle of rotation α (alpha).

The first coupling part 1 has a front end facing the second coupling part 2 and a rear end facing away from the second coupling part 2. At the rear end of the first coupling part 1, a cylindrical connection head 3 is provided, to which a tubular insertion section 4 connects to the front end of the first coupling part 1. In the preferred embodiments selected, the insertion section 4 is located on a tube 4a made of metal. The tube 4a is inserted into a blind hole 3a provided in the connection head 3 and is firmly and tightly connected to the connection head 3, for example by brazing. The insertion section 4 provided on the tube 4a projects beyond the connection head 3 on the end face.

An inner flow channel 5 leads through the coupling part 1 from the front end to the rear end. The inner flow channel 5 for the fuel is connected to the first fuel line 6 at the rear end of the first coupling part 1 and runs through the connection head 3 and the plug-in section 4 to the tip of the plug-in section 4 on the front Ren end of the first coupling part 1. The tube 4a with the insertion section 4 carries on its outside a seal 60, which in the embodiment shown in FIG. 1 is composed of a spacer sleeve 7 adjoining the connection head 3, which has a sealing ring 8 connects to which a spacer ring 9 and a second sealing ring 10 are arranged.

The second coupling part 2 comprises a sleeve-shaped plug-on section 11, the inner flow channel 12 for the fuel of which is connected to a second fuel line 13 at the rear end of the second coupling part 2 facing away from the first coupling part 1. The plug-on section 11 contains a cylindrical section 14 which is arranged adjacent to the front end of the second coupling part 2 facing the first coupling part 1. The cylindrical section 14 is formed by a bore which leads from the front end of the coupling part 2 into the coupling part 2. A part of the cylindrical section 14 serves as a sealing section 14a, on which, as soon as the two coupling parts 1, 2 are connected to one another, the seal 60 seals. The sealing section 14a is provided for receiving the seal 60 of the insertion section 4 of the first coupling part 1. The section 14 is followed by a further cylindrical section 15, which is provided for receiving the part of the plug-in section 4 of the first coupling part 1 which projects beyond the seal 60. The hollow section 15 leads into the fuel line 13.

For the tight connection of the two fuel lines 6 and 13, the first coupling part 1 with its plug-in section 4 is pushed axially into the sleeve-shaped plug-in section 11 of the second coupling part 2. The seal 60 of the plug-in section 4 is inserted into the section 14 of the plug-on section 11. On the cylindrical one Section 14 provided sealing section 14a, the seal 60 seals the circumferential gap between the plug-in section 4 and the plug-on section 11 in a fluid-tight manner, so that no fuel can escape from the axial through-channel of the coupling, which comprises the two flow channels 5, 12 and is formed by both coupling parts 1, 2. In this position, the two coupling parts 1 and 2 are connected to one another by a mechanically locked holding device 62, which essentially comprises an engagement section 16 provided on the coupling part 1, an engagement section 17 provided on the second coupling part 2, and an engagement section 16, 17 which is pushed axially into one another interlocking holding element 18 (Fig. 3) comprises.

The first engagement section 16 of the holding device 62 is arranged adjacent to the insertion section 4 in the connection head 3 of the first coupling part 1. This engagement section 16 contains axial longitudinal channels distributed over its circumference, which are open radially outwards and are separated from one another by axial longitudinal ribs. For the following description, the axial longitudinal channels receive the designation recesses 19 of the first coupling part 1, and the axial longitudinal ribs are referred to below as projections 20 of the first coupling part 1.

The second engagement section 17 of the holding device 62 is provided at the front end of the sleeve-shaped push-on section 11 of the second coupling part 2. This engagement section 17 contains axial longitudinal slots distributed over its circumference, which are axially open to the outside and are separated from one another by axial finger-shaped projections 22. The axial longitudinal slots receive the designation depressions 21 of the second coupling part 2.

The axial longitudinal channels or depressions 19 of the first inlet Handle section 16 are axially aligned with the axial finger-shaped projections 22 of the second engagement section 17. The width of the axial depressions 19 of the first engagement section 16 measured in the circumferential direction is in each case greater than the width of the finger-shaped projections 22 of the second engagement section 17 measured in the circumferential direction, as can be seen in FIGS. 4, 5, 6. Accordingly, the axial projections 20 of the first engagement section 16 are axially aligned with the axial depressions 21 of the second engagement section 17. The width of the axial projections 20 of the first engagement section 16 measured in the circumferential direction is in each case smaller than the width of the axial recesses 21 of the second engagement section 17 measured in the circumferential direction, as can also be seen in FIGS. 4, 5, 6.

Figures 4, 5 and 6 show a cross section through the coupling. The sectional plane of the cross section shown in FIGS. 4, 5 and 6 is marked IV - IV in FIG. 3.

Each of the four projections 20 (FIG. 1) or six projections 20 (FIGS. 2, 3, 4, 5, 6) of the coupling part 1 each have an essentially radial one, which runs counterclockwise (with reference to FIG. 4a) Rotation limitation surface 20a and a substantially radially extending, clockwise rotation limitation surface 20b. Provided on each of the four or six projections 22 of the coupling part 2 are an essentially radially extending, clockwise (further referring to FIG. 4a) rotating limiting surface 22a and a substantially radially extending, counterclockwise rotating limiting surface 22b.

The two coupling parts 1, 2 can be rotated relative to one another by a fixed, predeterminable angle of rotation α (alpha). In the fi guren 4, 5, 6, the two coupling parts 1, 2 are shown aligned with each other so that the projections 22 provided on the second coupling part 2 are approximately in the middle of the recesses 16 provided on the first coupling part 1. If one looks at one of the projections 22 of the coupling part 2 with this alignment of the two coupling parts 1, 2, then it can be seen that in the circumferential direction between the rotation limitation surface 22a and the rotation limitation surface 20a of the adjacent projection 20 of the first coupling part 1 there is an angular distance α1 (alpha 1) remains free, and between the rotation limiting surface 22b of the projection 20 and the rotation limiting surface 20b of the adjacent projection 20 there remains a free angular distance aλ (alpha 2). The angular distances α1 (alpha 1) and α2 (alpha 2) together result in the angle of rotation α (alpha) by which the two coupling parts 1, 2 can be freely rotated relative to one another about their longitudinal axis.

When rotating about the longitudinal axis of the two coupling parts 1, 2 against one another, depending on the direction of rotation, either the rotation limiting surface 20a comes into contact with the rotation limiting surface 22a or the rotation limiting surface 20b against the rotation limiting surface 22b. Depending on the manufacturing accuracy of the coupling parts 1, 2 and depending on the torque that rotates the two coupling parts 1, 2 against each other, either only one rotation limiting surface 20a and 22a or 20b and 22b comes into mutual contact or several or all rotation limiting surfaces 20a and 22a come into contact or 20b and 22b of each projection 20 and each projection 22 mutually to the system. The fact that the angle of rotation α (alpha) is limited at large points at high torque results in an even distribution of the torque to be absorbed, so that even a relatively large torque, which rotates the two coupling parts 1, 2 against one another, does not result in inadmissible deformation or damage to the Clutch leads. In the illustrated embodiments, the rotation limiting surfaces 20a, 20b of the coupling part 1 run parallel to one another, which has the advantage that the projections 20, where they abut the tube 4a, are not too narrow and thus a stable connection between the tube 4a and the Projections 20 is possible. The angle of the rotation limitation surfaces 22a, 22b of the projections 22 is adapted to the angle of the rotation limitation surfaces 20a, 20b of the projections 20 in such a way that the fullest possible contact between the rotation limitation surfaces 20a, 22a and 20b, 22b takes place. It should be pointed out that an essentially strictly radial alignment of the rotation-limiting surfaces 20a, 20b, 22a, 22b is also possible.

The axial longitudinal ribs or projections 20 of the first engagement section 16 have grooves 23 on their outer sides which are open to the outside circumferentially and which together form a circumferential groove of the first engagement section 16 which is interrupted by the axial longitudinal channels or recesses 19. With reference to FIGS. 1 and 2, the circumferential groove of the first engagement section 16 consisting of the grooves 23 has a left groove end 23a and a right groove end 23b.

The axial finger-shaped projections 22 of the second engagement section 17 likewise have on their outer sides circumferentially open grooves 24, which together form a circumferential groove of the second engagement section 17 which is interrupted by the axial longitudinal slots or depressions 21. Also with reference to FIGS. 1 and 2, the circumferential groove of the second engagement section 17 consisting of the grooves 24 has a left groove end 24a and a right groove end 24b.

The grooves 23 and 24 have essentially the same diameter in their groove base. The two engagement sections 16, 17 of the holding device 62 each have first or second locking elements arranged eccentrically to the axial through-channel of the coupling, that of the recesses 19 and projections 20 of the first coupling part 1 on the one hand and of the finger-shaped projections 22 and recesses 21 of the second Coupling part 2 are formed on the other hand. These locking elements are pushed axially into one another when the two coupling parts 1, 2 are inserted into one another. In this case, a peripheral movement play remains between the first and second locking elements, which limits the angle of rotation α (alpha) when the two coupling parts 1, 2 are rotated relative to one another.

As the embodiment shown in FIG. 1 shows, the first coupling part 1 has, for example, four depressions 19 and four projections 20; accordingly, four depressions 21 and four projections 22 are provided on the second coupling part 2. In the exemplary embodiment according to FIGS. 2 to 6, six depressions 19 and six projections 20 are provided on the first coupling part 1 and six depressions 21 and six projections 22 are correspondingly provided on the second coupling part 2. Although it is possible in principle to provide only one recess 19 and only one projection 20 on the first coupling part 1, and accordingly only to form one recess 21 and only one projection 22 on the second coupling part 2, it is more expedient, at least two each, for the purpose of uniform distribution of force over the circumference. it is better to provide at least three recesses 19, 21 and projections 20, 22 per coupling part 1, 2.

The locking elements of the two engagement sections 16, 17 are assigned to one another in pairs. In each case a first locking element formed in the first engagement section 16, together with the associated second locking element formed in the second engagement section 17, forms a locking element. pair of elements, the locking elements of which engage in axially nested engagement sections 16, 17 with peripheral movement play, which limits the angle of rotation α (alpha) when the two coupling parts 1, 2 are rotated relative to one another.

In the exemplary embodiments shown in FIGS. 1 to 6, an axial recess 19 and the finger-shaped projection 22 axially aligned therewith each form a pair of locking elements. In the case of axially nested engagement sections 16, 17, the narrower finger-shaped projection 22 is accommodated in the wider recess 19 and the difference in the peripheral widths of these locking elements 19 and 22 limits the peripheral movement play of the two coupling parts. In the same way, an axial projection 20 and the axial recess 21 axially aligned thereon form a pair of locking elements. In the case of axially nested engagement sections 16, 17, the narrower longitudinal rib or the narrower projection 20 is accommodated in the wider longitudinal slot or in the wider recess 21 and the difference in the peripheral widths of these. Locking elements 20 and 21 limit the peripheral movement play of the two coupling parts 1, 2.

The two axially nested engagement sections 16, 17 of the holding device 62 have a common, outwardly open circumferential groove, which is formed by the circumferentially aligned grooves 23 and 24, which are on the outer sides of the, of the projections 20 of the first Engagement section 16 and the finger-shaped projections 22 of the second engagement section 17 formed locking or locking elements are arranged. In axia ^¬ ler direction of the coupling parts 1, 2, considered is the groove 24 of the coupling member 2 dimensioned approximately the same as the groove 23 of the coupling part 1. If so, as is the case with the preferably selected exemplary embodiments, the two grooves 23, 24 in viewed in the axial direction are the same width, then run when the coupling parts 1, 2 are inserted, the left groove end 23a of the coupling part 1 and the left groove end 24a of the coupling part 2 viewed in the circumferential direction in alignment with each other, and the right groove ends 23d and 24b of the two coupling parts 1, 2 are aligned in the circumferential direction. The circumferential groove consisting of the grooves 23, 24 forms an outer locking groove of the holding device 62, into which the holding element 18 is inserted as a locking element with axial movement play. As a result, the two engagement sections 16, 17 are held axially displaceably in mutual engagement. The axial movement play results because the holding element 18, viewed in the axial direction, is shorter than the grooves 23 and 24.

The holding element 18 of the holding device 62, which is received in the locking groove with axial movement play, forms a loosely movable but difficult to separate mechanical connection of the two engagement sections 16 and 17 of the fluid-tightly inserted coupling parts 1, 2. When the two coupling parts 1, 2 are rotated relative to one another, they limit Locking elements 19, 20, 21, 22 of the holding device 62 have the angle of rotation α (alpha). When the two coupling parts 1, 2 move axially relative to one another, the locking elements 18, 23, 24 of the holding device 62 limit the displacement path. The holding device 62 enables mutual alignment of the coupling parts 1 and 2, which are already connected to one another in a fluid-tight manner, within the limits specified by the locking elements or locking elements.

In the preferred embodiments selected, the holding element 18 is formed directly in the locking groove (in situ) from an essentially U-shaped metal bracket 25, the clear width of which is slightly larger than the diameter of the groove base of the locking groove formed from the grooves 23 and 24. The width of the metal bracket 25 is somewhat small - ner than the width of the locking groove. The metal bracket 25 has, for example, a back 25a and two legs 25b. The back 25a can be curved in an arc (FIG. 4a) or straight (FIGS. 5a, 6a). Its legs 25b are straight. The ends of the legs 25b facing away from the back 25a are slightly beveled, so that a more or less blunt tip is formed here. The metal bracket 25 is inserted with the tips of its straight legs 25b into the locking groove and shaped into a more or less closed metal ring 18 by a bending tool (not shown in more detail). A metal bracket 25 (FIG. 4) with an arched back 25a can be shaped into a closed or largely closed ring (FIG. 4b). A metal bracket 25 with a straight back 25a can either be arched only on its straight legs (FIG. 5b) or can each be arched on backs 25a and legs 25b. The metal bracket 25 shown in FIGS. 6a and 6b is pressed so strongly into the locking groove with a tool that the back 25a deforms during assembly.

Depending on the length of the legs 25b of the metal bracket 25, which can have, for example, a curved back 25a (FIG. 4a) or a straight back 25a (FIGS. 5a, 6a), the metal bracket 25 encloses the two coupling parts 1 and 2 only partially or else Completely.

To release the coupling, the holding element 18 must first be cut open with a saw, for example, or bent open with a bending tool and removed from the locking groove. Only then can the two coupling parts 1, 2 be pulled apart axially.

Viewed in the radial direction, the metal bracket 25 can be made relatively thin. This makes it possible when the metal bracket 25 is installed in the locking groove 23, 24 To form metal bracket 25 with little effort and to install in the locking groove 23, 24. Because it is easily possible to make the groove ends 23a, 23b, 24a, 24b of the locking groove 23, 24 radially (ie perpendicular to the longitudinal axis), there is a risk that the holding element 18 when the coupling parts 1, 2 are loaded, for example by train or internal Pressure to be easily pushed out of the locking groove 23, 24. The metal bracket 25 is at most loaded in the axial direction to pressure, which is easy to control even with a simple use of materials. As a result, the holding element 18 can be made relatively easily from a small amount of material. Even with great force acting on the coupling parts 1, 2 there is no danger that the holding element 18 could be bent.

FIGS. 7 to 11 show a further embodiment of a coupling which enables a limitedly movable and fluid-tight connection of two fuel lines 26 and 30 and can only be released with a tool. This coupling is preferably used in a fuel supply device of an injection system of a two-row internal combustion engine, for example to connect one end of a connecting line running transversely to the rows of cylinders to one end of a distribution line running parallel to one row of cylinders in a fluid-tight manner and with limited movement.

The first coupling part 27 (FIG. 7a) is attached to one end of the connecting line 26 formed by a rigid metal tube, while the second coupling part 28 (FIG. 7b) is integrated with its sleeve-shaped push-on section 29 into the end of the fuel line 30, which is parallel to a row of cylinders of the internal combustion engine is arranged and carries the injectors provided for this row of cylinders. The first coupling part 27 can be divided into a front end closer to the fuel line 30 or the second coupling part 28 and a rear end away from the fuel line 30 or the second coupling part 28. The first coupling part 27 has at its rear end a connection head 31 to which a tubular insertion section 32 connects to the front end of the first coupling part 27. The rigid metal tube of the fuel line 26 extends with its straight tube end through the connection head 31 into the plug-in section 32 and forms the inner flow channel for the fuel.

The connection head 31 is formed by a cup-shaped metal sleeve which is placed on the straight pipe end of the connecting line 26 and is soldered or welded there.

FIG. 7a shows the connection head 31 after it has been fastened to the fuel line 26. FIG. 8 shows, on a different scale, the same section plane through the connection head 31 as FIG. 7a, but before the connection head 31 is fixed to the fuel line 26. FIG. 9 shows an end view of the connection head 31 shown in Figure 8. The viewing direction for the view shown in Figure 9 is marked in Figure 8 with IX.

The connection head 31, formed for example as a deep-drawn part made of sheet metal, has an end wall 33, an outer jacket 34 and a cylindrical inner jacket 45. The inner jacket 45 is fastened to the fuel line 26, for example by soldering.

The annular, flat bottom of the metal sleeve of the connection head 31 forms the radial end wall 33 of the connection head 31, which is designed as a locking section of the first coupling part 27. The end wall 33 contains four, each as an arch Mige window trained, axial passage openings, which are arranged along the outer edge of the end wall 33 evenly distributed over the circumference. The passage openings of the connection head 31 forming the windows are subsequently referred to as depressions 35 of the first coupling part 27. The width of the arcuate depressions 35 measured in the circumferential direction corresponds to the angle 36 (FIG. 9).

The outer substantially cylindrical jacket 34 of the metal sleeve of the connection head 31 extends coaxially to the insertion section 32 away from the end wall 33 and contains the locking section of the first coupling part 27. The jacket 34 has four, essentially U-shaped, radial openings 37 which are evenly distributed over the circumference and are arranged at a distance from the end wall 33. Each U-shaped opening 37 surrounds a rectangular tab 38, which ends in a free edge 39 running transversely to the insertion section 32 and is bent inwards into the connection head 31 by a parallel bending edge 40.

The insertion section 32 is provided with a sleeve 41, which extends from its front end backwards to the end wall 33. The sleeve 41 is made, for example, of injection-molded plastic and is therefore easy to manufacture and can easily be pushed onto the end of the fuel line 26 facing the second coupling part 28 with little pressure. A seal package 50 is arranged on the outside of the sleeve 41 (FIG. 11). This consists of a spacer sleeve 50a adjoining the end face 33, a first sealing ring 50b adjoining the spacer sleeve 50a, a spacer ring 50c adjoining the first sealing ring 50b and a second sealing ring 50d adjoining the spacer ring 50c. The spacer sleeve 50a and the spacer ring 50c serve to radially guide the two coupling parts. le 27, 28 against each other. The spacer sleeve 50a, the sealing ring 50b, the spacer ring 50c and the sealing ring 50d can be pushed onto the insertion section 32 in a simple manner until the spacer sleeve 50a abuts the end wall 33 of the connection head 31. The spacer sleeve 50a and the spacer ring 50c also serve to create an installation space for the sealing rings 50b, 50d, without therefore having to make a recess for the sealing rings 50b, 50d in one of the components.

A circumferential seal 52, for example an O-ring, is provided for the purpose of sealing between the sleeve 41 which is pushed onto the fuel line 26 with a slight pressure (FIGS. 7a, 11).

FIG. 10 shows an end view of the end of the second coupling part 28 facing the coupling part 27. The direction of view for the view shown in FIG. 10 is marked with X in FIG. 7b.

The plug-on section 29 of the second coupling part 28 integrated into the distribution line or fuel line 30 carries at its free, front end four, axial, finger-shaped projections 42 with an arcuate cross-section. The projections 42 are arranged distributed uniformly over the circumference of the plug-on section 29 and each taper in the axial direction towards their free ends. The width of the arcuate projections 42 measured in the circumferential direction corresponds to the angle 43 (FIG. 10).

If one looks at the second coupling part 28 from its end facing the first coupling part 27, then behind the projections 42 an outwardly open, approximately V-shaped circumferential groove 44 is let into the outside of the plug-on sections 29. The peripheral groove 44 is to the front (to the left in FIGS. 7b and 11) by a front boundary wall 44a which is perpendicular or almost vertical to the longitudinal axis of the plug-on sections 29 and to the rear (to the right in FIGS. 7b and 11) by a slightly inclined to the longitudinal axis of the plug-on sections 29, rear boundary wall 44b limited. Between the projections 42 and the circumferential groove 44, the push-on section 29 has an outer diameter 29a (FIG. 7b) which is somewhat smaller than the inner diameter of the jacket 34 of the connecting head 31 and approximately larger than that diameter which is from the free edges 39 of the inwardly bent tab 38 of the jacket 34 of the connection head 31 is formed.

On the inside of the plug-on section 29, a bore is provided behind the projections 42, which forms a sealing section 46 and which is adjoined by a cylindrical section 47, to which a further cylindrical section 48 connects. The cross-sectionally curved projections 42 of the plug-on section 29 are axially aligned with the through-openings or recesses 35 in the cross-section of the end wall 33 of the connecting head 31. The circumferential width of the arcuate projections 42 indicated by the angle 43 is smaller than the width of the arcuate depressions 35 indicated by the angle 36 and measured in the circumferential direction.

For the tight connection of the two fuel lines 26 and 30, the first coupling part 27 with its plug-in section 32 is inserted axially into the sleeve-shaped plug-on section 29 of the second coupling part 28. The seal package 50 of the plug-in section 32 is received in the seal section 46 of the plug-on section 29, and the part of the plug-in section 32 projecting axially beyond the seal pack 50 is in the cylindrical section 47 of the plug-on section adjoining the seal section 46. εchnitteε 29 added.

When joining the two coupling parts 27 and 28, d. H. When inserting the sealing package 50 into the sealing section 46 and the parts of the insertion section 32 projecting axially beyond the sealing package 50 into the cylindrical section 47, the connection head 31 is pushed onto the free end of the push-on section 29. The through openings or recesses 35 arranged in the end wall 33 of the connecting head 31 are pushed axially over the projections 42 of the plug-on sections 29. A projection 42 of the second coupling part 28 projects into a recess 25 of the first coupling part 27.

Furthermore, when the two coupling parts 27, 28 are joined together, the outer jacket 34 of the connection head 31 is pushed over the outside of the plug-on section 29 until the rectangular tabs 38 of the outer jacket 34 snap into the outer circumferential groove 44 of the plug-on sections 29. The inwardly bent tabs 38 of the outer jacket 34 are pressed elastically outward by the projections 42 and the section of the second coupling part 28 having the outer diameter 29a until they snap inward into the peripheral groove 44 when the front boundary wall 44a of the peripheral groove 44 is crossed , in which they then face the free boundary 39 of the front boundary wall 44a.

When the two coupling parts 27, 28 which are locked together are pulled apart, the tabs 38 snapped into the circumferential groove 44 are supported forwards with their free edges 39 on the front boundary wall 44a of the circumferential groove 44 and with their inwardly facing side walls on the rear boundary wall 44b of the circumferential groove 44 inwards, so that the flaps 38 do not bend and the flaps 38 slide out of the circumferential groove 44. This will achieved that the two coupling parts 27, 28 can be plugged together very easily and then form a durable bond that is not accidentally released by accidental external forces.

However, it is also conceivable that the connecting head 31 is made of a material which is more plastically deformable, and the flaps 38 are only bent inwards with a tool around the bending line 40 after the plug-on section 29 has been inserted into the connecting head 31, so that also In this variant, the free edges 39 of the tabs 38 protrude into the circumferential groove 44 and can be supported on the front boundary wall 44a of the circumferential groove 44.

In the embodiment shown in FIGS. 7 to 11, an axial recess 35 in the radial end wall 33 of the connection head 31 of the first coupling part 27 forms the first blocking element and the finger-shaped projection 42 of the axially aligned with this passage opening 35 Plug-on sections 29 of the second coupling part 28 the second locking element of a locking element pair of the holding device 62 of the coupling. Between the two locking elements of a pair of locking elements, in the case of coupling parts 1, 2 which are pushed axially one inside the other, a peripheral movement is provided which limits the angle of rotation α (alpha) when the two coupling parts 1, 2 are rotated in opposite directions. The size of this peripheral movement is essentially determined by the difference between the two angles 36 and 43.

In the embodiment shown in FIGS. 7 to 11, the outer jacket 34 of the connection head 31 of the first coupling part 27 with its four rectangular tabs 38 on one side and the circumferential groove 44 of the push-on section 29 of the second coupling part 28 on the other hand engage with one another locking elements of the holding device direction 62 of the clutch.

The locking elements of the holding device 62 formed by the interaction of the tabs 38 of the coupling part 27 and the circumferential groove 44 of the coupling part 28, viewed in the longitudinal direction of the coupling parts 27, 28, are matched in length in such a way that when the two coupling parts 27, 28 are so are pushed together as far as possible, a distance s remains free between the front boundary wall 44a of the circumferential groove 44 of the coupling part 28 and the free edge 39 of a tab 38 of the first coupling part 27. The result of this is that the two coupling parts 27, 28 can be pulled apart until the distance s has been overcome. The distance ε allows the two coupling parts 27, 28 to move with respect to one another in the axial direction. The sealing section 46 is so long that with the axial movement play of the two coupling parts 27, 28 against one another, the sealing package 50 is located within the sealing section 46 and thus also during the axial movement of the two coupling parts 27, 28 and during mutual rotation by the permitted angle of rotation α ( alpha) a fluid-tight connection of the fuel line 26 to the fuel line 30 is ensured.

In order to release the coupling, the rectangular tabs 38 bent inwards into the connection head 31, which are only accessible via the U-shaped openings 37 surrounding them, must first be bent out of the circumferential groove 44 of the plug-on section 29. Only then can the two coupling parts 27, 28 be axially pulled apart. Because a tool is required to bend the tabs 38 out of the circumferential groove 44, it is ensured that the two coupling parts 27, 28 do not unintentionally disengage.

In the embodiment shown in FIG. 1 engage on each of the two coupling parts 1, 2 four projections 20, 22 each in four recesses 19, 21 of the respective other coupling part 1 or 2. In the embodiment shown in FIGS. 7 to 11, four projections 42 also engage in four recesses 35 of the other coupling part 27. Because the projections 20, 22 and 42 and the recesses 19, 21 and 35 are evenly distributed over the circumference, the two coupling parts 1, 2 and 27, 28 can be pivoted around before assembly 90 degrees again a position can be found that enables assembly of the two coupling parts 1, 2 or 27, 28. Because the embodiments shown in FIGS. 2 to 6 each have εechε projections 20, 22 and correspondingly six recesses 19, 21, a position can be found again by pivoting the two coupling parts 1, 2 against each other by 60 degrees, which assembly allows two coupling parts 1, 2. It should be noted that in the exemplary embodiments shown, the number of projections 20, 22, 42 and depressions 19, 21, 35 can be selected in accordance with the respective requirement.

As already mentioned, the coupling with the coupling parts 1, 2 and 27, 28 is preferably provided for fuel lines 6, 13 and 26, 30 in which one of the fuel lines serves as a fuel distribution line and the other fuel line serves as a connecting line. FIG. 12 shows a corresponding exemplary embodiment, in which the coupling with the coupling parts 27, 28 is designed in accordance with FIGS. 7 to 11. In FIG. 12, the fuel line 30 serves as a fuel distribution line. The arrangement shown serves, for example, to supply fuel to an internal combustion engine with two parallel rows of cylinders. The fuel line 30 or the fuel distribution line 30, which is preferably made of plastic, is, for example, in the longitudinal direction of a not shown arranged internal combustion engine arranged. Several nozzles branch off from the fuel line 30, on which injectors 64 are made in accordance with the number of cylinders of the internal combustion engine. On the fuel line 30, one or more fastening tabs 66 are formed, with which the fuel line 30 can be screwed onto the cylinder head of the internal combustion engine (not shown). In the embodiment shown in FIG. 12 there is a further fuel line 30 'parallel to the fuel line 30. Both fuel lines 30, 30 'are identical. The fuel lines 30, 30 ′ are connected to one another via the fuel line 26. The fuel line 26 serving as a connecting line is designed in an arc shape so that there is sufficient space for the internal combustion engine below the arc.

Both ends of the fuel line 26 are each connected to the fuel line 30 or to the fuel line 30 'via a coupling each having a holding device 62. Couplings can also be provided at the ends of the fuel lines 30, 30 'which are not shown in FIG. 12 and which are designed in the same way as the couplings shown in FIG. With one of these couplings, for example, the fuel line 30 is connected to a line leading from a fuel pump, and the fuel line 30 'is connected, for example, with a coupling designed according to the invention to a return line leading to a reservoir.

In the exemplary embodiment shown in FIG. 12, the fuel line 30, the fuel line 30 ', the fuel line 26 and the injection valves 64 can be assembled in advance before these parts are attached to the internal combustion engine. The fuel lines 26, 30, 30 'and the injection valves 64 form part of a preliminary assembly. assembly that can be assembled separately from the internal combustion engine. Because dimensional tolerances for the installation of the injection valves 64 and for the fastening holes for the fastening tabs 66 (FIG. 12) can never be completely excluded in the internal combustion engine, it is important that the coupling with the coupling parts 1, 2 and 27, 28 have a certain degree Tolerance compensation allows. As already explained, the holding device 62 with the coupling parts 1, 2 or 27, 28 permits both a relative pivoting of the fuel line 6 or 30, 30 'with respect to the fuel line 13 or 26 by the angle of rotation α (alpha) and a certain amount axial displacement by a certain amount, which is denoted by the distance s in FIG.

In order that the fuel lines 30, 30 'can only be connected to the fuel line 26 in the correct manner without much thought, it is proposed to make the circumferential distance between the individual projections 42 unevenly. Accordingly, the depressions 35, viewed in the circumferential direction, must also be distributed unevenly in the same way. In the embodiment shown in FIG. 12, the coupling part 28 has four projections 42 and accordingly the coupling part 27 has four depressions 35, three of the projections 42 and three of the depressions 35 being visible in FIG. 12. One of the visible projections of the coupling shown on the right in FIG. 12 is marked with the reference number 42.1. The two other visible projections bear the reference symbols 42.2 and 42.3. As shown in FIG. 12, viewed in the circumferential direction, the distance between the two projections 42.1 and 42.2 is substantially greater than the distance between the two projections 42.2 and 42.3. Accordingly, it is also on the coupling between the fuel line 30 and the fuel line 26. This ensures that the fuel lines 26, 30, 30 'can only be assembled correctly. A spatially incorrect assembly is excluded. The coupling parts 27, 28 shown in FIG. 12 can also be replaced by the coupling parts 1, 2, the details of which are shown in FIGS. 1 to 6. Even then, the distances between the projections 20, 22 and correspondingly also the distances between the recesses 19, 21 can be set differently in the circumferential direction, so that spatially incorrect joining of the coupling parts 1 and 2 is excluded.

Instead of plugging the seals 60 with the parts 7, 8, 9, 10 onto the plug-in section 4 prior to the assembly of the coupling parts 1, 2 (FIG. 1), it is also possible to seal the seal 60 with the seal ring 10 first, then the dielectric ring 9, then insert the sealing ring 8 and then the spacer sleeve 7 into the cylindrical section 14 of the second coupling part 2 before the two coupling parts 1, 2 are plugged together. In other words, the seal 60 can optionally be provided either on the first coupling part 1 or on the second coupling part 2.

In the embodiment shown in FIGS. 7 to 11, too, the sealing package 50 can be connected to the first coupling part 27 either by pushing it onto the insertion section 32 before the two coupling parts 27, 28 are plugged together, or the sealing package 50 in the sealing section 46 of the second coupling part 28 are pushed in, the sealing ring 50d first, then the spacer ring 50c, then the sealing ring 50b and then the spacer sleeve 50a being pushed into the sealing section 46.

The sealing rings 8, 10 (FIG. 1) or 50b, 50d (FIG. 11) can be applied, for example, to the plug-in section 4 or 32 or to the seal section 14a or 46, respectively. vulcanized sealing material to be replaced.

The plug-in section 4 engages in section 15 (FIG. 1) or the plug-in section 32 engages in section 47 (FIG. 7). Through this mutual engagement of the coupling parts 1, 2 and 27, 28, the coupling parts 1, 2 and 27, 28 are mutually guided. Because of the circular shape of the insertion section 4 or 32 and the circular shape of the section 15 or 47, an axis of rotation A is obtained which is central to the sections 4, 15 and 32, 47. This axis of rotation A is shown in FIGS 7 symbolically represented by a dash-dotted line marked with A. The coupling parts 1 and 2 or 27 and 28 can be rotated relative to each other about the axis of rotation A by the predetermined angle of rotation. The projections 20, 22 and 42 together with the recesses 19, 21 and 35 form locking elements. With these locking elements 19, 20, 21, 22 (Fig. 1) and 35, 42 (Fig. 2), the range of motion in the circumferential direction between the two coupling parts 1, 2 and 27, 28 is limited to the predetermined angle of rotation. So that the locking elements 19, 20, 21, 22; 35, 42 limit the movement ε play around the axis of rotation A to the predetermined angle of rotation, d. H. so that an effective lever arm is created, the locking elements, i. H. the projections 20, 22 and 42 and the depressions 19, 21 and 35, respectively, are arranged at a radial distance from the axis of rotation A.

The passage channel for the fuel formed by the two coupling parts 1, 2 and 27, 28 runs essentially parallel to the axis of rotation A and preferably centrally through the coupling parts 1, 2 and 27, 28. In the case of the coupling parts 2, 28 injection molded from plastic whose wall thicknesses do not have to be the same everywhere along the circumference, the centrally arranged through channel can also run more or less eccentrically to the axis of rotation A.

Claims

Claims:

1. Coupling for fuel lines or the like, in which a first coupling part (1; 27) connected to a first fuel line (6; 26), which has an insertion section (4; 32) and one in the insertion section (4; 32 ) opening internal flow channel for the fuel is inserted, with its plug-in section (4; 32) inserted into a plug-on section (11; 29) of a second coupling part (2; 28) which is connected to a second fuel line (13; 30) and is provided with an inner flow channel for the fuel opening into the plug-on section (11; 29), the two fluid-tight coupling parts (1, 2; 27, 28) forming a passage channel for the fuel being connected to one another by a holding device are characterized in that the holding device (62) at least one pair when inserting the two coupling parts (1, 2; 27, 28) into each other and each on egg Nem coupling part (1, 2; 27, 28) arranged blocking elements (19, 20, 21, 22; 35, 42), between which, in the case of coupling parts (1, 2; 27, 28) which are inserted into one another in a fluid-tight manner, a movement play limited to a predeterminable angle of rotation is provided, and that the holding device (62) comprises at least two locking elements (18, 23, 24; 38, 44) which, when the coupling parts (1, 2; 27, 28) are inserted into one another in a fluid-tight manner, and locking elements (19, 20, 21, 22; 35, 42) can be brought into engagement with one another in order to hold the two coupling parts (1, 2; 27, 28) together.

2. Coupling according to claim 1, characterized in that each ^¬ weils a ersteε locking element (19, 20; 35) on the first coupling part (1; 27) iεt arranged zuεammen with a second locking element (21, 22; 42), arranged on the second coupling part (2; 28) and on the first locking element (19, 20; 35) is aligned, forming a pair of locking elements.

3. Coupling according to claim 2, characterized in that an axial recess (19; 35) is provided as the first locking element, which is arranged on the first coupling part (1; 27), and that a projection (22; 42) is provided as the second locking element which is arranged on the second coupling part (2; 28), the width of the axial recess (19; 35) measured in the circumferential direction being greater than that of the projection (22; 42).

4. Coupling according to claim 3, characterized in that the axial recess as an outwardly open longitudinal channel (19) of the first coupling part (1) is formed, in which, with fluid-tight coupling parts (1, 2), a finger-shaped projection (22) is added as a second locking element.

5. Coupling according to claim 3, characterized in that the axial recess as an axial passage opening (35) of the first coupling part (27) is formed, which, with fluid-tight coupling parts (27, 28), of a finger-shaped projection (42) is second Blocking element is enforced.

6. Coupling according to claim 2, characterized in that as a first locking element a longitudinal rib (20) on the first coupling part (1) and as a second locking element an axial recess (21) on the second coupling part (2) is provided, the width of the longitudinal rib ( 28) is smaller than that of the axial recess (21).

7. Coupling according to one of claims 1 to 6, characterized in that at least two pairs of locking elements are provided, which are diametrically opposed to one another with respect to the through channel opposite.

8. Coupling according to one of claims 1 to 6, characterized in that several pairs of locking elements are arranged circumferentially evenly distributed.

9. Coupling according to one of claims 1 to 8, characterized in that the holding device for mutually locking the two coupling parts (1, 2) has at least two axially pushable ones when the two coupling parts (1, 2) are inserted into each other and in each case on a coupling part (1, 2) arranged locking elements (20, 22), on the outer sides of which circumferential grooves (23, 24) are provided, which are aligned with one another when the fluid-tight coupling parts (1, 2) are inserted and form a locking groove into which a locking element (18) is inserted.

10. Coupling according to claim 9, characterized in that the, with fluid-tight nested coupling parts (1, 2), with a peripheral movement interlocking locking elements (20, 22) are also formed as locking elements which are on their outer sides the circumferential grooves (23, 24 ) for the locking element.

11. Coupling according to claim 9 or 10, characterized in that daε interlocking element as a, in the interlocking groove (23, 24) auε formed a metal bracket (25) bent metal ring (18) iεt.

12. Coupling according to one of claims 1 to 8, characterized in that a locking section (34) is provided for mutually locking the two coupling parts (27, 28) on the first coupling part (27), which, in the case of fluid-tight coupling parts (27, 28 ), the free end of the plug-on section (29) of the second coupling part (28) overlaps and at least contains a permanently deformable locking element (38) which can be brought into engagement with a recess (44) arranged on the outside of the plug-on section (29) of the second coupling part (28).

13. Coupling according to claim 12, characterized in that the locking section (34) has a plurality of, with fluid-tightly inserted into one another coupling parts (27, 28) around the plug-on section (29) uniformly distributed, permanently deformable locking elements (38), which with a circumferential groove (44) arranged on the outside of the plug-on section (29) can be brought into engagement.

14. Coupling according to one of claims 1 to 8, characterized in that a locking element (38) is provided on the one coupling part, which engages elastically when the coupling parts are inserted into one another in a boundary wall (44a) provided on the other coupling part.