The invention relates to a plug-in connector for a fluid line and to a plug-in connection which comprises such a plug-in connector and a mating plug-in connector.

Plug-in connections of this type serve to releasably connect fluid-conducting pipe or hose lines to one another.

Important requirements regarding the development of such plug-in connections include, inter alia, a structurally simple configuration, in order to realize low production costs, simple handleability, both in the case of the connection of the individual plug-in connectors to the pipe and hose lines and in the case of the releasable connection of the plug-in connectors to one another, and furthermore permanent leakproofhess.

DE 20 2009 000 328 Ul discloses a plug-in connector for a fluid line, which comprises a first part and a second part connected thereto. The first part forms a connecting portion for fastening the plug-in connector to a hose line. The second part and a portion of the first part form an accommodating means, into which a mating plug-in connector can be plugged and can be locked in the plugged-in position by means of an elastic locking clip. A sealing element in the form of an O-ring is arranged in a groove-like depression in the region of the accommodating means. The depression is formed here by both the first part and the second part. In order to connect the two parts, the second part forms an annularly encircling step which engages in a complementary depression in the first part. The two parts can thus be connected in different rotary orientations with respect to each other. The permanent connection between the two parts is subsequently obtained by welding.

DE 20 2007 006 954 Ul discloses a plug-in connector which is provided at one end for connection to a pipeline. For this purpose, the plug-in connector forms an accommodating means, into which one end of the pipeline can be plugged. The accommodating means is bounded with respect to the end side of the pipeline by an end side of a basic body and with respect to the outer side of the pipeline by a bushing of the plug-in connector. For the permanent connection of the three components, the bushing which extends over both a portion of the pipeline and of the basic body is welded to said components. This is intended to take place by means of laser welding, for which purpose the bushing is formed from a plastic which is transparent to laser beams, and the basic body is formed from a plastic absorbing laser beams.

The invention is based on the object of specifying a plug-in connector which can be produced in an advantageous manner for a fluid line.

This object is achieved by means of a plug-in connector as claimed in patent claim 1. A plug- in connection having such a plug-in connector and a complementary mating plug-in connector is the subject matter of patent claim 10. Advantageous refinements of the plug-in connector according to the invention and of the plug-in connection according to the invention are claimed in the further patent claims and emerge from the description below of the invention.

A plug-in connector for a fluid line, which comprises at least a first part, which forms a channel for guiding a fluid, and a second part, which forms an accommodating means, into which a mating plug-in connector can be plugged by a movement along a plug-in direction, wherein the first part and the second part form a contact plane, in which said two parts are welded to one another, is characterized, according to the invention, in that at least one portion of the second part, starting from an outer surface which is formed by the same, can be arranged on the outer side or inner side of the plug-in connector and extending up to the region of the contact zone, is of laser-transparent design, and a laser-absorbing material is provided in the region of the contact zone.

A plug-in connection according to the invention comprises at least one plug-in connector according to the invention and a complementary mating plug-in connector.

The refinement according to the invention of the plug-in connector makes it possible for the latter to be able to be produced particularly advantageously. Relatively complex geometries of the plug-in connector can namely be realized by the combination of at least two parts which can themselves have relatively simple geometries. It is thus made possible in particular for the two parts of the plug-in connector to be advantageously injection-molded from plastic, as a result of which high piece numbers can be accompanied by low piece costs.

According to the invention, the at least two parts of the plug-in connector are connected by laser welding by laser radiation being absorbed in the contact zone and thereby being converted into thermal energy which leads to melting and mixing of the materials forming the contact zone. After the laser irradiation is ended, the melt hardens again and leads to the desired integrally bonded connection between the two parts of the plug-in connector. According to the invention, the use of very different laser welding methods, such as, for example, simultaneous welding, contour welding, radial welding or quasi-simultaneous welding, is possible.

According to the invention, the terms "laser-absorbing" and "laser-transparent" are understood comparatively, and therefore the material of the laser-absorbing portion has greater absorption capability for laser radiation than the material of the laser-transparent portion. It can preferably be provided that the material of the laser-absorbing portion is intensely and particularly preferably virtually completely laser-absorbing such that impingement of the laser radiation on said portion leads to heating and melting of an edge region which is as narrow as possible and bounds the contact zone. The material of the laser- transparent portion is preferably as far as possible less laser-absorbing in order to ensure that the laser radiation penetrates in as unhindered a manner as possible.

An example of a suitable laser-transparent material is PA 66 GF 30 natural, i.e. polyamide 66 with a reinforcement composed of 30% of glass fibers without or with coloring, but which is not laser-absorbing to the relevant extent (for example Masterbatch black). An example of a suitable laser-absorbing material is PA 66 GF 30 black, in which the black coloring is achieved by a carbon additive which is intensely laser-absorbing. PA 66 GF 30 basically has advantageous mechanical characteristic values, is stable in relation to a multiplicity of oils and fats and is also readily weldable. By means of the use of PA 66 GF 30 as the basic material (with different additives) for both the first part and the second part, particularly good weldability of said parts can be achieved. In addition, substantially identical mechanical characteristic values can have an advantageous effect with regard to the tightness in the event of changing ambient temperatures. A use of an identical basic material for the first part and the second part, in which the differently laser-absorbing material properties are achieved by different additives, can therefore constitute a basically advantageous refinement of the plug- in connector according to the invention. Of course, different basic materials for the first part and the second part are also possible.

In an advantageous refinement of the plug-in connector according to the invention, it can be provided that the first part of the plug-in connector, at least in the region of the contact zone, is particularly preferably completely formed from a laser-absorbing material. At the same time, the second part of the plug-in connector can preferably be completely formed from a laser-transparent material. By means of the thus permitted use of only one material per part of the plug-in connector, the production of the latter can be further simplified.

However, it is also possible to provide the first part, which is basically of laser-transparent design, on the contact surface, which forms the contact zone, with a laser-absorbing coating, and therefore the choice of the material used for the first part is free with regard to the absorption capability for laser radiation.

In a furthermore preferred refinement of the plug-in connector according to the invention, it can be provided that the contact zone runs parallel to, or obliquely (i.e. at an angle of between 0° and < 90°) in relation to, the plug-in direction. It is thus made possible to form a comparatively large contact zone without dimensions, which are increased for this purpose, having to be provided for the plug-in connector. Furthermore, welding by means of laser can thereby be permitted from the side. This not only permits good accessibility to the point at which the laser is intended to be fitted, but also relatively short distances for the laser radiation through the laser-transparent portion of the first part.

In a development of such a plug-in connector according to the invention, it can also be provided that the first part forms a protrusion, which encircles the accommodating means and is accommodated in a complementary depression of the second part, and, in the process, forms the contact zone. This makes it possible to obtain a particularly large contact zone which can ensure good retainability of the connection between the first and the second part. The depression here can preferably be designed in such a manner that the encircling protrusion of the first part is accommodated on both sides in the depression. It is thus made possible to further increase the contact zone and/or to provide two contact zones: a contact zone facing the outer side of the plug-in connector and a contact zone facing the inner side of the plug-in connector.

If the protrusion and therefore also the depression are of annularly and consequently rotationally symmetrically encircling form, the effect can furthermore be achieved that the first part and the second part are connectable to each other in any rotary orientation (with respect to a longitudinal axis of the accommodating means, which is preferably oriented coaxially with respect to the plug-in direction). This can have an advantageous effect in particular if the mating plug-in connector of the plug-in connection according to the invention can be plugged into the accommodating means of the plug-in connector only in one or more specific rotary orientations, and/or if the channel of the first part has a curved or angled profile. It is namely thereby made possible to define the rotary orientation of the mating plug- in connector with respect to the curved or angled profile of the channel only when the first part and the second part are welded together. Consequently, a plurality of plug-in connectors which differ in respect of said rotary orientation of the mating plug-in connector can be formed from identical first and second parts.

Plug-in of the mating plug-in connector into the accommodating means of the plug-in connector in only one or more specific rotary orientations can advantageously be achieved in that the cross section of the accommodating means is not rotationally symmetrical in at least one longitudinal portion (i.e. in a portion extending along the longitudinal axis of the accommodating means).

In a preferred refinement of the plug-in connector according to the invention, it can be provided that the accommodating means for the mating plug-in connector extends into the first part. The effect can thereby be achieved that the mating plug-in connector also extends into the first part, and therefore a direct connection can be brought about between a channel formed by the mating plug-in connector and the channel formed by the first part of the plug- in connector according to the invention. The effect can thereby be achieved in particular that the fluid flow guided in the channels does not come into contact as far as possible with the laser-transparent material of the second part. This constitutes an advantage in particular in the case of the preferred use according to the invention of the plug-in connector according to the invention and/or of the plug-in connection according to the invention for guiding a coolant, in particular in a cooling system of an internal combustion engine, since a good portion of the known laser-transparent plastics are not uncovered for contact with the customary coolants.

The plug-in connector according to the invention and the plug-in connection according to the invention are suitable in principle for guiding any fluid (gas and/or liquid, for example oil, air, etc.).

The tightness of a plug-in connection according to the invention can be improved in a simple manner in that a sealing element arranged in the region of the accommodating means is provided.

In order to secure the position, it can be provided that the sealing element is arranged in a groove-like depression. Since such a groove-like depression can constitute an undercut during the production of the plug-in connector by, in particular, injection molding, it can furthermore preferably be provided that the groove-like depression is bounded by both the first part and the second part and consequently is formed only when said two parts are put together. The groove-like depression therefore must not itself constitute any undercut during the production of the two parts of the plug-in connector.

The sealing element can also help here to prevent contact of the laser-transparent material of the second part with the fluid guided through the plug-in connector or the plug-in connection. For this purpose, it should then be provided that the first part forms a first side surface and the base surface and the second part forms the second side surface, of the groove-like depression.

The indefinite articles ("a" and "of a"), in particular in the patent claims and in the above description explaining the patent claims in general, should be understood as such and not as numerals. Components correspondingly substantiated therewith should therefore be understood as meaning that said components are present at least once and may be present more than once.

The invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings. In the drawings

Fig. 1 : shows a first refinement of a plug-in connector according to the invention in a side view;

Fig. 2: shows a longitudinal section through the plug-in connector according to fig. 1 along the intersecting plane II-II in fig. 1 ;

Fig. 3: shows a second refinement of a plug-in connector according to the invention in a side view;

Fig. 4: shows a longitudinal section through the plug-in connector according to fig. 3 along the intersecting plane IV-IV in fig. 3;

Fig. 5: shows a third refinement of a plug-in connector according to the invention and of a complementary mating plug-in connector in a longitudinal section;

Fig. 6: shows a fourth refinement of a plug-in connector according to the invention and of a complementary mating plug-in connector in a longitudinal section;

Fig. 7: shows a view of a plug-in connector according to fig. 5 or 6 with a second part of the plug-in connector in a first rotary orientation; and

Fig. 8: shows a view according to fig. 7 with the second part of the plug-in connector in a second rotary orientation.

The plug-in connector 1 illustrated in figs. 1 and 2 comprises a first part 2 and a second part 3, which are connected immovably to each other. A continuous channel 4 for guiding a fluid is formed on the inside of the first part 2. On the outside, the first part 2 forms a connecting portion 5 onto which a, for example, pipe- or hoselike fluid line (not illustrated) can be plugged.

In the present exemplary embodiment, the channel 4 merges coaxially into an accommodating means 6, which is formed by the second part 3 and by a portion of the first part 2 adjacent to the second part 3. A mating plug-in connector 10 (cf. figs. 5 and 6) can be plugged into the accommodating means 6 by a movement in the plug-in direction 8. While the channel 4 has a circular cross section which is constant over the length, the accommodating means 6 is divided into portions with respect to the longitudinal axis 7 thereof, wherein said portions differ in respect of the cross sections thereof.

Starting from that end of the plug-in connector 1 which is formed by the second part 3, the accommodating means 6 forms a first portion with a relatively large cross section which is basically circular in this exemplary embodiment. In this portion of the accommodating means 6, two diagonally opposite guide grooves 18, which prevent complete rotational symmetry of said portion, are also placed into the wall of the second part 3. In conjunction with complementary guide protrusions of the mating plug-in connector 10, the guide grooves 18 have the effect that the mating plug -in connector 10 can be plugged into the accommodating means 6 in only a specific rotary orientation with respect to the longitudinal axis 7. Furthermore, a transverse slot 9 extending through part of the plug-in connector 1 transversely with respect to the longitudinal axis 7 is provided in the region of this first portion of the accommodating means 6. A locking clamp (not illustrated) can be inserted into said transverse slot and can then also engage in a locking groove 11 of the mating plug-in connector 10 and can thereby secure the latter in the accommodating means 6 of the plug-in connector 1.

A second portion of the accommodating means 6, again with a circular cross section, is of conically tapering design. An adjoining third portion (with a circular cross section) which is already formed by the first part 2 of the plug-in connector 1 has a cross section which is enlarged in relation to the smallest cross section of the second portion. By contrast, the adjoining fourth portion is formed with a cross section corresponding to the smallest cross section of the second portion.

The third portion constitutes a groove-like depression 12 which serves for accommodating a sealing element 13 (cf. figs. 5 and 6). A first side surface and a base surface of the depression 12 is formed here by the first part 2 and a second side surface is formed here by the second part 3 of the plug-in connector 1.

At the end adjacent to the second part 3, the first part 2 has a protrusion 14 which extends coaxially with respect to, and therefore parallel to, the longitudinal axis 7 of the accommodating means 6 and encircles the accommodating means 6 in a closed manner. The free end of said protrusion forms a portion of reduced wall thickness, as a result of which a step is formed on the inner side of the protrusion. The protrusion 14 engages in a depression, which is matched thereto, of the second part 3, wherein the outer side of the protrusion 14 makes expansive contact with an associated contact surface of the depression of the second part 3 while contact of the inner side of the protrusion 14 is provided only in the portion of reduced wall thickness. A permanent connection of the first part 2 and of the second part 3 to each other by welding is provided in the contact zone 16 formed between the outer side of the protrusion 14 and the associated mating contact surface of the second part 3.

The welding is carried out by means of laser welding. For this purpose, the entire first part 2 is formed from a laser-absorbing material, for example PA 66 GF 30 black, while the second part 3 is composed of a laser-transparent material, for example PA 66 GF 30 natural. The laser beams 15 which are indicated by arrows in fig. 2 can therefore pass from an outer surface, which is formed by the outer side of the second part 3, as far as the corresponding portion of the contact zone 16 where said laser beams are substantially completely absorbed. The resulting conversion of laser energy into thermal energy results in melting of the materials of the first part 2 and of the second part 3 in the contact zone 16. After re-hardening of the melt, the two parts 2, 3 of the plug-in connector 1 are connected to each other in an integrally bonded manner. The portion of the encircling protrusion 14 of reduced wall thickness, which portion makes contact both on the inner side and on the outer side with associated mating contact surfaces of the second part 3, serves for supporting mechanical loads, in particular vibration loads, and therefore the welded joint is intended to be relieved from said loads.

The plug-in connector 1 illustrated in figs. 3 and 4 differs from the previously described plug- in connector 1 substantially only in the configuration of the encircling protrusion 14 of the first part 2 and of the depression, which is complementary with respect thereto, of the second part 3. In this refinement, the protrusion 14 is firstly of conically tapering design (as seen in the plug-in direction) on the inner side. Secondly, said protrusion is accommodated over the entire length on both sides in a complementary depression of the second part 3. Accordingly, a contact zone 16 which is oriented in an inclined manner in relation to the longitudinal axis 7 of the accommodating means 6 is formed on the inner side of the protrusion 14. It is envisaged welding the plug-in connector 1 according to figs. 3 and 4 on the inner side, but with welding on the outer side, such as in the case of the plug-in connector 1 according to figs. 1 and 2 also (alternatively or additionally) being possible. By means of the oblique orientation of the contact zone 16, the welding can take place by means of a laser 17 arranged outside the accommodating means 6 without recourse having to be made to deflecting devices arranged in the accommodating means 6 for the laser beam.

Furthermore, in the case of the plug-in connector 1 according to figs 3 and 4, the second part 3 also forms an encircling protrusion 19 which is accommodated in a contact manner on both sides in a complementary depression of the first part 2. Like the portion of the protrusion 14 of reduced wall thickness and the associated portion of the depression in the second part 3 in the case of the plug-in connector 1 according to figs. 1 and 2, said protrusion/depression system serves for supporting mechanical loads, in particular vibration loads, as a result of which the welded joint is intended to be correspondingly relieved of load in the contact zone 16.

The plug-in connector 1 shown in fig. 5 differs from that according to figs. 1 and 2 only in the refinement thereof as an angular plug-in connector. For this purpose, that portion of the first part 2 which forms the channel 4 has a profile curved by approx. 90°. In addition, a mating plug-in connector 10 associated with the plug-in connector 1 and a sealing element 13 accommodated in the groove-like depression 12 are shown in fig. 5.

The plug-in connector 1 shown in fig. 6 constitutes a corresponding modification of the plug- in connector 1 shown in figs. 3 and 4.

Figs. 7 and 8 also clarify the possibility provided in the case of the plug-in connectors 1 according to figs. 1 to 6 of connecting the second parts 3 to the associated first parts 2 in any rotary orientation as a consequence of the rotationally symmetrical configurations of the encircling protrusions 14 and of the depressions accommodating the latter. In particular in the case of the angular plug-in connectors according to figs. 5 and 6, this constitutes an advantage since the rotary orientations of the mating plug-in connectors 10, which can be plugged into the accommodating means 6 only in specific rotary orientations as a consequence of the guide protrusions projecting into the guide grooves 18 of the accommodating means 6, can thereby be selected as desired with respect to the connecting portions 5, which are oriented at an angle.

List of Reference Numbers

1 Plug-in connector

2 First part of the plug-in connector

3 Second part of the plug-in connector

4 Channel

5 Connecting portion

6 Accommodating means

7 Longitudinal axis of the accommodating means

8 Plug-in direction

9 Transverse slot

10 Mating plug-in connector

11 Locking groove

12 Groove-like depression

13 Sealing element

14 Protrusion

15 Laser beams

16 Contact zone

17 Laser

18 Guide groove

19 Protrusion