CONNECTOR FOR A PLUG CONNECTOR SYSTEM

Description

[0001] The invention relates to a connecting part for a plug-in connection system of a coupling device for automatically coupling a trailer vehicle to a towing vehicle, comprising a contact carrier, a contact structure attached to the contact carrier, which can be brought into engagement with a contact structure of a complementary connecting part of the plug-in connection system in order to establish a plug-in connection with the complementary connecting part during automatic coupling, a closure flap pivotable relative to the contact carrier, which is pre-tensioned onto the contact carrier and, when the plug-in connection is established, can be released from the contact carrier in a pivoting movement against this pre-tension, and a seal arranged on the contact carrier, which is elastically deformable by a counterpart pressing on the seal in order to seal the contact structure from the outside.The counterpart is formed by the closure flap pressing on the seal when the plug connection is released, and by the complementary connecting part of the plug connection system pressing on the seal when the plug connection is established. The invention further relates to a plug connection system for a coupling device for automatically coupling a trailer to a towing vehicle.

[0002] In the commercial vehicle sector, coupling devices are known that serve to automatically couple a trailer to a towing vehicle. For example, a semi-trailer typically has a pin located on its underside that can be positively locked into a fifth wheel coupling of a tractor unit. In addition to this mechanical coupling, a plug-in connection system is also provided to supply the trailer with electrical power and / or compressed air. It is also possible to transmit electrical and / or optical control signals between the tractor unit and the semi-trailer via such a plug-in connection system. Plug-in connection systems of this type are known, for example, from the publications DE 10 2008 014 285 A1 and DE 10 2008 014 572 B4.

[0003] Accordingly, such a plug connection system is formed from two associated connecting parts, one of which is mounted on the towing vehicle and the other on the trailer vehicle. Each of these connecting parts has a contact carrier and a plurality of contact elements attached to it, which engage in pairs with the associated contact elements of the other connecting part when the trailer vehicle is coupled to the towing vehicle. As a rule, the contact elements provided on one connecting part are designed as plugs, while the contact elements of the other connecting part form complementary sockets. When the plugs engage with their associated sockets, the plug connections required for the supply of electrical energy, electrical and / or optical control signals, and compressed air are established between the two connecting parts.

[0004] To protect the contact structure formed by the contact elements from environmental influences such as water, dust, etc., the connecting part has a closing flap pivotally mounted on the contact carrier, which is preloaded towards the contact carrier, for example by a spring. In the uncoupled state, the closing flap presses on a seal attached to the contact carrier. This seal is made of an elastic material so that it deforms when the spring-loaded closing flap presses on the seal. In the coupled state, in which the plug-in connection is established between the two connecting parts forming the plug-in connection system, a suitable mechanism in the interaction of the two connecting parts ensures that the closing flap is pivoted away from the seal against the preload force.In this state, the other connecting part of the plug-in connection system presses on the seal in order to seal the engaged contact elements fluid-tight against the outside space.

[0005] In the prior art, the seal is formed from a sealing plate which merges integrally into individual sealing lips, each of which annularly encloses one of the contact elements. A further circumferential sealing lip is formed on the edge of the sealing plate and encloses the contact structure formed from the contact elements as a whole. The individual sealing lips each have a sealing profile in the form of a simple elevation which extends in a direction perpendicular to the plate plane. Thus, the sealing lip is subjected to pressure by the respective sealing counterpart, i.e. in the uncoupled state by the closure flap and in the coupled state by the complementary connecting part, in a direction which coincides with the direction in which the sealing lip protrudes from the plate plane.

[0006] With regard to the sealing performance of such a seal, it must be considered that conventional sealing materials exhibit a certain compression set value (DVR), which is a measure of how much time the sealing material requires to return to its original geometry after being subjected to compression. In this context, it must also be considered that the plug-in connection system exerts significantly different pressure forces on the seal when connected and disconnected. For example, in the unconnected state, the closure flap preloaded onto the seal exerts a significantly lower pressure force on the seal than the complementary connecting part of the plug-in connection system, for example, via pneumatic actuation, does in the connected state.Accordingly, after a certain period of time in the coupled state, the seal takes significantly longer to return to its original geometry than it does from the uncoupled state. This can lead to the subsequent pressure force exerted on the seal by the pre-tensioned closure flap in the coupled state being insufficient to ensure adequate sealing of the contact structure from the outside. This can allow water or dust to enter the area of ​​the contact structure and contaminate or even damage it.

[0007] To achieve the desired tightness, one could consider increasing the preload force with which the closure flap is pressed against the seal when uncoupled. However, this would result in a correspondingly large force counteracting the preload, which must be applied when establishing the plug connection to open the closure flap. The mechanisms currently used to open the closure flap might then no longer be suitable and would have to be retrofitted or replaced, which is avoidable due to cost considerations.

[0008] From the document DE 10 2018 113776 A1 a connecting part for a plug connection system according to the preamble of claim 1 is known.

[0009] German patent document DE 100 15 420 A1 discloses a coupling assembly for rail vehicles. This coupling assembly comprises a coupling housing with a coupling opening that can be tightly closed by a flap pivotally mounted on the housing between a closed position and an open position. The coupling opening is surrounded by a lip seal, against which the flap rests in the closed position.

[0010] The document US 1 790 292 A also describes a plug connection system in which a closure cap rests on a seal when closed.

[0011] The object of the present invention is to provide a connecting part for a plug-in connection system of a coupling device that enables an improved sealing effect with minimal technical effort. Furthermore, the object of the invention is to provide a plug-in connection system with such a connecting part.

[0012] The aforementioned objects are achieved by the connecting part according to claim 1 and the plug connection system according to claim 11. Advantageous further developments emerge from the dependent claims and the following description.

[0013] The connecting part according to the invention comprises a contact carrier, a contact structure attached to the contact carrier, which can be brought into engagement with a contact structure of a complementary connecting part of the plug connection system in order to establish a plug connection with the complementary connecting part during automatic coupling, a closure flap which can be pivoted relative to the contact carrier, which is pre-tensioned onto the contact carrier and can be released from the contact carrier in a pivoting movement against this pre-tension when the plug connection is established, and a seal arranged on the contact carrier, which is elastically deformable for sealing the contact structure from the outside by a counterpart pressing on the seal,The counterpart is formed by the closure flap pressing against the seal when the plug connection is released, and by the complementary connecting part of the plug connection system pressing against the seal when the plug connection is established. The contact carrier has at least one sealing groove surrounding the contact structure. The seal is formed from at least one sealing lip, which is inserted into the sealing groove and thus encloses the contact structure. The sealing lip has a sealing profile that is inclined toward a side facing away from the contact structure, so that the sealing lip deforms elastically toward this side when the counterpart presses against the sealing lip.

[0014] In contrast to conventional seals, whose sealing lips form elevations projecting perpendicularly from the contact carrier, the sealing lip according to the invention has a quasi-asymmetrical and undercut sealing profile such that the profile section projecting from the contact carrier is inclined outwards relative to the surface normal of the contact carrier, i.e., away from the contact structure enclosed by the sealing lip. This means that in the present invention, in contrast to the prior art, the direction in which the sealing lip rises from the contact carrier does not coincide with the direction of the compressive load exerted on the sealing lip by the sealing counterpart, i.e., the spring-loaded closure flap in the uncoupled state.This results in the sealing profile of the sealing lip, which in this case is understood to be the cross-section through the sealing lip, springing outwards as it were when pressure is applied, which provides various advantages over conventional sealing geometries.

[0015] This means that the sealing material is subjected to less stress by the sliding of the sealing lip than in a case where the direction of extension of the sealing profile coincides with the direction of pressure application. This results in a longer service life for the seal. It also reduces the compression set, allowing the sealing lip to return to its original shape more quickly after being subjected to high pressure while coupled. This ensures, particularly in the period immediately after the plug connection is released, that even the closure flap, which exerts a significantly lower pressure force on the seal, reliably seals the contact elements from the outside.Furthermore, the sealing profile according to the invention is selected such that, when the plug connection is released, water spray directed from the outside onto the connecting part acts on the outwardly elastically deformed sealing lip, causing the water to press the sealing lip even more firmly against the closure flap. This also increases the sealing effect of the connecting part according to the invention in the uncoupled state.

[0016] The seal according to the invention preferably consists exclusively of the at least one sealing lip, which is fastened in the associated sealing groove formed in the contact carrier, e.g. by injection molding. In other words, with the exception of one or more sealing lips, the seal has no further sealing structures such as a sealing plate used in the prior art. This ensures that the pressure surface is defined essentially solely by the length of the sealing lip (or by the summed length when using multiple sealing lips). For a given pressure force with which the closure flap acts on the seal, this results in increased surface or line pressure on the sealing edge, which further increases the sealing effect. In particular, a comparatively moderate preload of the closure flap can be used to achieve the desired seal.This makes it easier to open the closing flap when coupling the trailer to the towing vehicle, counteracting the pre-tensioning force with which the closing flap presses onto the seal.

[0017] The sealing lip has a profile section that protrudes from the contact carrier and tapers with increasing distance from the contact carrier. This allows the sealing edge, formed by the free end of the profile section, to be kept narrow to increase surface pressure. Furthermore, the tapered section makes the sealing lip more flexible. At the same time, the tapered section strengthens the sealing lip in line with the bending moment profile. This means that the sealing lip is comparatively thin at its tip, i.e., in the area of ​​its sealing edge where a lower bending moment acts, and becomes thicker towards the contact carrier, where a higher bending moment acts.

[0018] In a preferred embodiment, the sealing lip has a profile section protruding from the contact carrier, which has a first profile side facing the contact structure and a second profile side facing away from the contact structure, each of which has an inclination directed away from the contact structure, wherein the inclination of the first profile side is greater than the inclination of the second profile side. In this way, it is ensured that the sealing edge formed by the free end of the profile section is at a greater distance from the contact structure in the projection onto the contact carrier than a base point of the second profile side, which is defined by the end of the second profile side opposite the sealing edge on the plate plane. A pressure force acting on the sealing edge thus reliably ensures that the sealing profile springs outwards away from the contact structure.

[0019] For example, the profile section protruding from the contact carrier essentially has the shape of an inclined triangle. However, it goes without saying that a different sealing geometry can also be selected, provided that such a geometry achieves elastic deformation in the desired direction, i.e., in a direction away from the contact structure.

[0020] The sealing groove defines a first groove space, defined by a recess formed in the contact carrier, and a second groove space, which adjoins the first groove space and is wider than the first groove space. In this embodiment, the sealing lip can have a sealing seat secured in the first groove space, while the profile section of the sealing lip adjoining the sealing seat is elastically deformable in the widened second groove space. The second groove space defined by the sealing groove provides the sealing lip with sufficient space to deflect the compressive load to the side without damaging the sealing lip.

[0021] The aforementioned two-stage design of the sealing groove is in accordance with the invention. In another embodiment, which is not part of the claimed invention, a single-stage design of the sealing groove is also possible, i.e., a design in which two differently sized groove spaces of the type described above are dispensed with.

[0022] In a special embodiment, several contact elements forming the contact structure can be enclosed by a single sealing lip. Alternatively, the use of several sealing lips is also possible, each of which then encloses a portion of the contact elements.

[0023] The contact elements are designed as plug-in connection elements that can be engaged in pairs with the respective plug-in connection elements of the contact structure of the complementary connecting part to establish the plug-in connection. The respective plug-in connection element can be designed as a plug or a socket. In this case, all plug-in connection elements on the connecting part considered here are preferably provided either in the form of a plug or a socket. Accordingly, the contact elements of the other connecting part are designed in the respective complementary form to provide the desired plug-in connections.

[0024] The sealing lip is preferably made of an elastic plastic, e.g., an elastomer or silicone. Based on such a material, the sealing lip can be manufactured, for example, by injection molding, in the desired design, especially with the desired elasticity.

[0025] Preferably, the connecting part comprises a pretensioning device designed to press the closure flap onto the sealing lip when the plug connection is released and, when the plug connection is established, to pivot the closure flap away from the sealing lip in cooperation with the complementary connecting part. Such a pretensioning device comprises, for example, one or more spring elements by which the closure flap is pretensioned on the contact carrier, so that the closure flap, in the uncoupled state, presses against the seal mounted in the contact carrier with the desired contact force.

[0026] A further aspect of the invention provides a plug-in connection system for a coupling device for automatically coupling a trailer vehicle to a towing vehicle. The plug-in connection system comprises a first connecting part of the type described above and a complementary second connecting part with a contact structure that can be brought into engagement with the contact structure of the first connecting part in order to establish a plug-in connection with the first connecting part during automatic coupling.

[0027] The invention is explained in more detail below with reference to the figures, in which: Figure 1 shows a perspective view of a connecting part of a plug-in connection system according to an embodiment with the closure flap open; Figure 2 shows a perspective view of the connecting part with the closure flap closed; Figure 3 shows a perspective view showing the closure part according to the Figures 1 and 2together with a complementary connecting part of the plug connection system with the plug connection released; Figure 4 shows a perspective view showing the two closure parts according to Figure 3 when the plug connection is established; Figure 5 shows a perspective view of two sealing lips according to an embodiment; Figure 6 shows a cross section through a sealing lip to illustrate the sealing profile; Figure 7 shows a sectional view through the two connecting parts forming the plug connection system in a state in which the plug connection is not yet fully established; Figure 8 shows a detailed view of the illustration according to Figure 7to illustrate the sealing profile when the plug connection is not yet fully established; Figure 9 shows a sectional view of the two connecting parts forming the plug connection system in a state in which the plug connection is fully established, and Figure 10 shows a detailed view of the illustration according to Figure 9 to illustrate the sealing profile when the plug connection is fully established.

[0028] In the Figures 1 and 2 A connecting part 100 according to the invention is shown as an exemplary embodiment, which is part of a plug-in connection system 102. The latter is in turn provided in a coupling device which serves to couple a trailer vehicle, e.g. a semi-trailer, to a towing vehicle. In addition to the Figures 1 and 2 The connector system 102 comprises a complementary connecting part 104, as shown in the Figures 3 and 4In this example, the Figures 1 and 2 The connecting part 100 shown can be mounted on the towing vehicle, while the other connecting part is provided on the trailer vehicle. However, it is also possible to provide an interchanged arrangement of the two connecting parts 100, 104.

[0029] The two connecting parts 100, 104 forming the plug-in connection system 102 serve to transmit electrical energy, compressed air, and electrical and / or optical control signals between the towing vehicle and the trailer. For this purpose, the two connecting parts 100, 104 each have a plurality of contact elements that are engaged with each other in pairs when the trailer is coupled to the towing vehicle. The contact elements, assigned in pairs, are each designed in the form of a plug and a socket to establish the desired plug connection during the coupling process.

[0030] At this point it should be noted that in the Figures 1 to 4To simplify the illustration, the aforementioned contact elements themselves are hidden and are shown only by means of recesses 106, 108, and 110, respectively, in which the contact elements are accommodated. Therefore, when the contact elements 106, 108, 110 are mentioned below, reference is made to these recesses. The contact elements of the complementary connecting part 104 assigned to the contact elements 108 of the connecting part 100 are shown in the Figures 3 and 4 not visible.

[0031] For those in the Figures 1 to 4In the embodiment shown, it can be assumed, for example, that the contact elements 106, 108 provided on the connecting part 100 mounted on the towing vehicle are designed as sockets. Accordingly, the complementary contact elements 110 of the connecting part 104 mounted on the trailer vehicle are designed as plugs. However, it is equally possible to provide the plugs and sockets in an interchangeable arrangement. An arrangement distributed across both connecting parts 100, 104, in which each connecting part 100, 104 has both plugs and sockets, is also conceivable.

[0032] In the following, with reference to the Figures 1 and 2The connecting part 100 mounted on the towing vehicle in the present embodiment is described in more detail. The connecting part 100 has a housing 112 and a contact carrier 114 mounted on the housing 112. Attached to the contact carrier 114 is a contact structure, generally designated 116, which is formed by the aforementioned contact elements 106, 108.

[0033] In the illustrated embodiment, the contact structure 116 comprises two contact units 118 arranged mirror-symmetrically to a vertical central axis, which serve, for example, to transmit electrical signals between the two connecting parts 100, 104. These two functional units 118 are formed by the contact elements 106. Furthermore, the contact structure 116 comprises two functional units 120 for transmitting compressed air, also arranged mirror-symmetrically on the contact carrier 114. These pneumatic functional units 120 are formed by the contact elements 108.

[0034] The contact carrier 114 further has a centering opening 122 in its central region, into which a matching centering rod (not shown) is inserted during the coupling process. The centering opening 122 and the associated centering rod have the function of aligning the two connecting parts 100, 104 in the correct position with one another, so that the contact elements 106, 108 of the connecting part 100 engage precisely with the associated contact elements of the complementary connecting part 104. Two recesses 124 formed on opposite sides of the housing serve the same function; during the coupling process, they interact with two matching guide rods (not shown) provided on the complementary connecting part 104. Figure 1Four mounting holes 126 are also shown around the centering opening, but these are not further important for understanding the embodiment according to the invention.

[0035] The connecting part 100 further comprises a closure flap 128, which serves to protect the contact carrier 114 and in particular the contact elements 106, 108 attached thereto from environmental influences such as dust and splash water. For this purpose, the closure flap 128 is mounted on the housing 112 such that it can be opened from an open position according to Figure 1 into a closed position according to Figure 2 is pivotable. In order to ensure the closure of the contact carrier 114 in the uncoupled state, the closure flap 128 is pre-tensioned onto the contact carrier 114 by means of a pre-tensioning device. This pre-tensioning device has, for example, two Figures 1 and 2tension springs (not shown) which are arranged on both sides of the housing 112 and pull the closure flap 128 in the direction of the contact carrier 114. The pretensioning device is further designed to cooperate in a manner known per se with the complementary connecting part 104 such that the closure flap 128, which is initially closed during coupling (cf. Figure 2 ) is opened against the preload force by being released from the contact carrier 114 in a pivoting movement (cf. Figure 1 ).

[0036] As in Figure 1As shown, a seal, generally designated 130, is arranged on the contact carrier 114. In the present exemplary embodiment, this seal comprises two first sealing lips 132 arranged mirror-symmetrically to one another and two second sealing lips 134, also arranged mirror-symmetrically to one another. The sealing lips 132, 134 are designed such that they entirely enclose the contact structure 116 formed from the contact elements 106, 108. The electrical contact elements 106 are enclosed by the two first sealing lips 132, and the two pneumatic contact elements 108 are enclosed by the two second sealing lips 134.

[0037] The seal, composed of sealing lips 132, 134, serves to seal the contact elements 106, 108 fluid- and dust-tight from the outside, both in the uncoupled and coupled states, in order to protect the contact elements 106, 108 from dust and splash water, for example. For this purpose, the seal 130 cooperates with a counterpart, which is formed by the closure flap 128 in the uncoupled state and by the complementary connecting part 104 in the coupled state. In both states, the respective counterpart presses against the seal 130, thus ensuring the desired seal.

[0038] As mentioned above, the pressure force exerted by the closure flap 128 on the seal 130 in the uncoupled state is significantly lower than the pressure force with which the complementary connecting part 104 presses on the seal 130 in the coupled state. As will be explained below, for this reason, the present invention aims in particular to advantageously configure the seal 130 composed of the sealing lips 132, 134 such that the seal 130 achieves a reliable seal of the contact structure 116 not only in cooperation with the complementary connecting part 104, but also in cooperation with the closure flap 128, which exerts only a comparatively low pressure force.

[0039] In Figure 5 are the first sealing lip 132 and the second sealing lip 134, which are each provided in duplicate in the present embodiment (cf. Figure 1), shown in perspective in a unique position. Figure 6 shows a cross-sectional view of the respective sealing lip 132, 134.

[0040] As in Figure 5 As shown, the two sealing lips 132, 134 each have a closed shape in order to completely enclose the contact elements 106, 108 assigned to them. The two sealing lips 132, 134 differ from one another in their contour, i.e. in the course in which they are guided around the contact elements 106, 108 assigned to them. These different contours are due to the respectively selected arrangement of contact elements 106, 108 and are to be understood purely as examples. What the two sealing lips 132, 134 have in common, however, is their property of elastically deforming in a direction that points away from the respectively enclosed contact structure when pressure is applied by the respective counterpart, i.e. the closing flap 128 or the complementary connecting part 104.

[0041] This sealing profile directed away from the contact structure is best used in Figure 6 Its mode of operation during the coupling process is described in the Figures 7 to 10 illustrated.

[0042] As in Figure 6 As shown, the sealing lip 132, 134 has a sealing seat 136 attached to the contact carrier 114. Adjoining this is a profile section 138, which projects from the sealing seat 136 and thus from the contact carrier 114. In the exemplary embodiment shown, the projecting profile section 138 tapers towards its free end, which forms a sealing edge 140. The latter first comes into contact with the respective sealing counterpart, ie during coupling with the complementary connecting part 104 and during uncoupling with the closure flap 128. The profile section 138 projecting from the contact carrier 114 is inclined outwards away from the enclosed contact elements 106, 108. In the special embodiment according to Figure 6The profile section 138 has an inner first profile side 142 and an outer second profile side 144, both of which are inclined outwards. The inner profile side 142 is inclined more strongly outwards than the outer profile side 144. Accordingly, the sealing edge 140 formed by the free end of the profile section 138 lies in the longitudinal section according to Figure 6 further outward than a base point 146, which is located at the transition between the sealing seat 136 attached to the contact carrier 114 and the outer profile side 144 of the profile section 138. The profile section 138 has in the configuration according to Figure 6 thus essentially the shape of an oblique triangle.

[0043] The sectional view according to Figure 7 and the resulting detailed view according to Figure 8show a state in which the two connecting parts 100, 104 are still spaced apart from each other in the plug-in direction during the coupling process, in which the sealing lip 132, 134 shown is just unaffected by the connecting part 104 forming the sealing counterpart. In contrast, the sectional view 9 and the detailed view derived therefrom according to Figure 10 the fully coupled state in which the complementary connecting part 104 presses on the sealing lip 132, 134. As shown in the Figures 9 and 10 As shown, the pressure force exerted by the complementary connecting part 104 ensures that the sealing profile springs outwards away from the enclosed contact structure and contacts the inner profile side 142 of the profile section 138 (cf. Figure 6 ) rests against the end face of the connecting part 104. This causes the contact elements 106, 108, which are located within the two Figures 9 and 10The sealing lips shown are arranged in a fluid- and dust-tight manner and sealed against the outside.

[0044] The sealing geometry according to the invention is selected such that the direction in which the sealing profile extends away from the contact carrier 114 does not coincide with the direction of pressure application, but is inclined outward relative to this direction. This counteracts material fatigue, which otherwise occurs over a multitude of coupling processes. Furthermore, this advantageously leads to a reduction in the compression set after the plug connection is released, so that the subsequent pressure force exerted by the closure flap 128 on the seal 130 is sufficient to achieve the desired seal.

[0045] The detailed view after Figure 10further shows that a sealing groove 148 with a stepped cross-section is provided in the contact carrier 114 for attaching the sealing lip 132, 134. It goes without saying that the sealing groove 148 in the contact carrier 114 has a profile that corresponds to the profile of the sealing lip 132, 134, which is to be secured in the sealing groove 148, for example, by injection molding. The sealing groove 148 defines a first groove space 150 and a second groove space 152 adjoining it in the axial direction, which is wider than the first groove space 150. The first groove space 150 serves to secure the sealing seat 136 of the sealing lip 132, 134.In contrast, the expanded second groove space 152 has the function of providing the profile section 138 of the sealing lip 132, 134, which adjoins the seal seat 136, with sufficient space for its elastic deformation when the complementary connecting part 104 presses against the sealing lip 132, 134 in the fully coupled state. In this way, the sealing groove 148 of the sealing lip 132, 134 offers sufficient opportunity to deflect the pressure sideways by elastic deformation, so to speak, without damaging the sealing lip 132, 134.

[0046] Referring to the detailed view after Figure 10A further advantage of the sealing geometry according to the invention is that splash water acting from the outside on the plug connection system 104 presses the elastically deformed sealing lip 132, 134 against the respective sealing counterpart, thereby increasing the sealing effect even further. In this context, it should be noted that the detailed view according to Figure 10 although on the Figure 9 illustrated situation in which the sealing counterpart is formed by the complementary connecting part 104. However, it goes without saying that the above explanations apply equally to the case in which the sealing counterpart is formed by the closure flap 128. List of reference symbols

[0047] 100Connecting part 102Connection system 104Complementary connecting part 106Contact element 108Contact element 110Contact element 112Housing 114Contact carrier 116Contact structure 118Functional unit 120Functional unit 122Centering opening 124Recess 126Mounting holes 128Closing flap 130Seal 132Sealing lip 134Sealing lip 136Sealing seat 138Profile section 140Sealing edge 142First profile side 144Second profile side 146Foot point 148Sealing groove 150First groove space 152Second groove space

Claims

1. Connecting part (100) for a plug-in connection system (102) of a coupling device for automatically coupling a trailer vehicle to a towing vehicle, comprising: a contact support (114), a contact structure (116), which is attached to the contact support (114) and can be brought into engagement with a contact structure of a complementary connecting part (104) of the plug-in connection system (102) in order to establish a plug-in connection with the complementary connecting part (104) during automatic coupling, a closure flap (128), which is pivotable relative to the contact support (114), is preloaded with respect to the contact support (114) and can be released from the contact support (114) against this preloading with a pivoting movement when the plug-in connection is established, and a seal (130), which is arranged on the contact support (114) and, for sealing off the contact structure (116) from the exterior space, can be elastically deformed by a mating piece which presses onto the seal (130), wherein the mating piece is formed by the complementary connecting part (104) of the plug-in connection system (102), the complementary connecting part pressing onto the seal (130), when the plug-in connection is established, wherein the contact support (114) has at least one seal groove (148), which surrounds the contact structure (116), and the seal (130) is formed from at least one sealing lip (132, 134), which is inserted into the seal groove (148) and has a seal profile which is inclined towards a side facing away from the contact structure (116), so that the sealing lip (132, 134) is elastically deformed towards this side when the mating piece presses onto the sealing lip (132, 134), and wherein the sealing lip (132, 134) has a profile portion (138), which projects from the contact support (114) and tapers as the distance from the contact support (114) increases, characterized in that the mating piece is formed by the closure flap (128) pressing onto the seal (130) when the plug-in connection is released, and in that the seal groove (148) defines a first groove space (150), which is given by a recess formed in the contact support (114), and a second groove space (152), which adjoins the first groove space (150) and is widened in relation to the first groove space (150), wherein the sealing lip (132, 134) has a seal seat (136), which is mounted in the first groove space (150), and the profile portion (138) of the sealing lip (132, 134), which profile portion adjoins the seal seat (136), is deformable in the widened second groove space (152).

2. Connecting part (100) according to Claim 1, characterized in that the sealing lip (132, 134) has a profile portion (138), which projects from the contact support (114) and has a first profile side (142), which faces the contact structure (116), and a second profile side (144), which faces away from the contact structure (116), the first and the second profile side each having an inclination directed away from the contact structure (116), wherein the inclination of the first profile side (142) is greater than the inclination of the second profile side (144).

3. Connecting part (100) according to Claim 1 or 2, characterized in that the profile portion (138) is substantially in the form of a slanted triangle.

4. Connecting part (100) according to any of the preceding claims, characterized in that the sealing lip (132, 134) has a closed shape.

5. Connecting part (100) according to any of the preceding claims, characterized in that the contact structure (116) comprises a plurality of contact elements (106, 108), which are surrounded by the at least one sealing lip (132, 134).

6. Connecting part (100) according to any of the preceding claims, characterized in that the at least one sealing lip comprises a plurality of sealing lips (132, 134), which each surround some of the contact elements (106, 108).

7. Connecting part (100) according to Claim 5 or 6, characterized in that the contact elements (106, 108) are embodied as plug-in connection elements, which can be brought into engagement with their respectively associated plug-in connection elements (110) of the contact structure of the complementary connecting part (104) in pairs.

8. Connecting part (100) according to Claim 7, characterized in that the respective plug-in connection element (106, 108) is embodied as a plug or a socket.

9. Connecting part (100) according to any of the preceding claims, characterized in that the sealing lip is manufactured from an elastic plastic.

10. Connecting part (100) according to any of the preceding claims, characterized by a preloading device which is designed to press the closure flap (128) onto the sealing lip (132, 134) when the plug-in connection is released and to pivot the closure flap (128) away from the sealing lip (132, 134) in interaction with the complementary connecting part (104) of the plug-in connection system (102) when the plug-in connection is established.

11. Plug-in connection system (102) for a coupling device for automatically coupling a trailer vehicle to a towing vehicle, comprising a first connecting part (100) according to any of the preceding claims and a complementary second connecting part (104) with a contact structure, which can be brought into engagement with the contact structure (116) of the first connecting part (100), in order to establish a plug-in connection with the first connecting part (100) during automatic coupling.