Abstract:
A plug-in connector assembly for connecting at least one fluid line to another fluid line or to an aggregate connection. The plug-in connector assembly includes, a housing, a mating plug-in connector and an adapter sleeve. The mating plug-in connector and the adapter sleeve are received within a sleeve section of the housing, with the adapter sleeve operating to attach the mating plug-in connector to the housing in a releasable manner.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the U.S. national phase of International Application No. PCT/EP2015/057243 filed on Apr. 1, 2015, and claims priority to DE 10 2014 107 655.9, filed May 30, 2014, the disclosures of which are incorporated in their entirety by reference herein. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a plug-in connector. 
       BACKGROUND 
       [0003]    A plug-in connector generally of the kind to which the present invention relates is known from German patent DE 10 2008 013 565 A1. 
         [0004]    The locking arms reach therein with their locking cams behind the annular collar of an inserted mating plug-in connector. The locking arms each have therefor a radially outwardly directed graded section, at whose free end is located the respective locking cam. In this way is obtained an enlarged diameter of the plug-in connector, so that the required installation space must be accordingly enlarged. In order to keep the length of the plug-in connector as small as possible, it is also necessary to provide axially running opening areas for accommodating the graded section with enlarged diameter, whereby the penetration of dirt particles is facilitated when the adapter sleeve is not plugged in. There is, moreover, a risk that an undesirable release can occur when the mating plug-in connector is plugged together, since the operating sections that project over the periphery of the sleeve section are easy to access. 
         [0005]    From patent DE 10 2011 084 988 is known a plug-in connector, in which the positive locking means located at the free end of the locking arms are formed on the outside thereof. The locking cams are likewise located on the lower side of these locking arms, so that the locking cams are located within the sleeve section. This arrangement and configuration of the positive elements and the locking cams require, on the one hand, a relatively elongated design of the sleeve section, and furthermore a relatively large section is located within the wall of the sleeve section, so that the locking arms are unprotected, and dirt can furthermore easily penetrate into the sleeve section. 
       SUMMARY 
       [0006]    It is an object of the present invention to prevent the disadvantages of the existing generic plug-in connector and to create a plug-in connector with very compact measurements, which ensures the total elasticity and flawless operation of the locking means within crowded installation conditions and makes possible a protected arrangement of the locking arms. An effective safeguarding of the locked position of the locking arms should at the same time be possible. 
         [0007]    The mating plug-in connector according to the principles of the present invention has a locking groove configured in the area of a plug shaft, into which the locking cams of the locking arms engage when the mating plug-in connector is plugged together. It is possible in this way, according to the invention, to limit the diameter of the adapter sleeve in the area of its annular collar in such a way that the outer diameter of the annular collar is not greater than the outer diameter of the sleeve section of the housing. An impairment of the elastic locking arms and damage thereof is prevented in this way even in a very crowded space conditions. According to the principles of the present invention, the adapter sleeve is essentially circumferentially protected within the housing, and the locking means are not a component of the housing, but the locking means are instead configured on the separate part of the adapter sleeve, which is inserted into the housing. It is thus possible to manufacture the adapter sleeve and the housing from different materials. The positively locking elements likewise make possible an axial fixation, especially a circumferential fixation, since they can be suitably positive-lockingly fixed in peripheral direction in the adapter sleeve. The adapter sleeve cannot be released via tensile stress as a result of the positive locking in the axial direction, and a twisting of the adapter sleeve is also prevented as a result of the positive locking in the peripheral direction. 
         [0008]    It can be advantageous according to the invention if the adapter sleeve has an annular collar that runs along the periphery of its rear opening edge seen from the direction of insertion, which is arranged outside of the sleeve section with the adapter sleeve in the inserted condition, wherein also the locking cams likewise run outside of the sleeve section. It may be advantageous according to the invention if the locking arms, which are offset by 180° with respect to each other, are provided on the adapter sleeve. The annular collar advantageously has a circular shape and its outer diameter is equal in size to an outer diameter of a circular shaped peripheral contour of the sleeve section of the housing. The annular collar thus does not project beyond the outer contour of the sleeve section, whereby a very compact design is obtained. 
         [0009]    The annular collar is suitably connected to the locking arms in the area of the locking cams and is separated by means of circumferential gap sections from the housing of the adapter sleeve. It is advantageous according to the invention if the annular collar is provided centrally between the locking arms with deformation sections, which can be deformed in such a way under a force directed toward the longitudinal center axis, that a radially outwardly directed spreading of the locking arms is produced in such way that the radial distance of the locking cams is equal to the inner diameter of the passage opening. The configuration of the annular collar according to the invention makes possible manual release of the inserted mating plug-in connector. 
         [0010]    According to this invention, it can likewise be advantageous if the annular collar has an oval shape, wherein its largest outer diameter is configured in the area of the operating sections and the annular collar, and its smallest diameter is configured in the area of the locking arms, and the largest outer diameter is greater than the outer diameter of the circular shaped peripheral contour of the sleeve section, and its smallest outer diameter is smaller than the outer diameter of the sleeve section. The locking arms are thereby radially inwardly deformed at their ends that face toward the cams in such a way that their radial distance to the longitudinal center axis is smaller than the inner radius of the passage opening, so that the annular collar has a circular shaped peripheral contour, whose outer diameter is smaller than/equal to the outer diameter of the sleeve section, in the locking position of the locking cams. 
         [0011]    It is also advantageous according to the invention if the thickness of the locking arms is less than the wall thickness of the adapter sleeve, so that a stepped surface running radially in the direction of the longitudinal center axis is configured between the outer periphery of the wall of the adapter sleeve and the locking arms. It is advantageous hereby if the dimensions of the radial height of the stepped surface and the length of the locking arms within the sleeve section are such that a radially outwardly directed spring path of the locking cams is provided in such a way that the radial distance of the radially outwardly spread locking cams is at least equal to an inner diameter of the adapter sleeve and at least equal to the outer diameter of the plug shaft of the mating plug-in connector. 
         [0012]    It is furthermore advantageous according to the invention if the locking extensions are formed by a radially elastically bendable arm that runs parallel to the longitudinal center axis, wherein the locking extensions are arranged diametrically opposite to each other and are offset by 90° with respect to the locking arms and have radially outwardly projecting locking cams at their free ends in insertion direction. 
         [0013]    It is advantageous if the locking arms are separated by a U-shaped slot from the wall of the adapter sleeve and are connected as one piece to the wall of the adapter sleeve by means of the end that faces opposite the direction of insertion. The adapter sleeve can thus be configured short and compact. The radial elasticity of the arms can be adjusted by modifying their length and thickness. It is furthermore advantageous if the locking cams of the locking arms rest with their free ends on a circular periphery, whose diameter is smaller than the outer diameter of the sleeve section and is larger than the inner diameter of the channel section of the sleeve section. The locking arms do not project hereby beyond the outer periphery of the sleeve section, whereby on the one hand damage to the locking cams is prevented and on the other hand the compact design of the plug-in connector according to the invention is supported. 
         [0014]    As a result of the configuration and arrangement according to the invention, the locking arms can be bent apart outwardly in the area of the locking cams during insertion by the plug-in connector, so that the locking arms with the annular collar are deformed in such a way during the plug-in operation that an insertion control is provided. 
         [0015]    It is furthermore advantageous according to the invention if a peripheral seal is arranged in front of the adapter sleeve in the passage opening of the sleeve section in the direction of insertion in order to seal a peripheral gap between an inner wall of the sleeve section and the socket shaft of the mating plug-in connector. 
         [0016]    It is likewise advantageous if an annular shoulder for application of the peripheral seal is configured in the sleeve section at the transition of the section with expanded diameter of the sleeve section to the passage channel and the peripheral seal is encapsulated between the annular shoulder and a front face of the adapter sleeve. This arrangement according to the invention makes it possible to avoid providing undercuts either in the plug-in connector or in the mating plug-in connector in order to achieve an encapsulation of the peripheral seal. The peripheral seal is additionally protected within the sleeve section. 
         [0017]    It can also be advantageous according to the invention to displaceably arrange a release safeguard at the outer periphery of the sleeve section in the direction of the longitudinal center axis between two locked positions, whereby the release safeguard prevents a spreading of the locking arms when in its locked position onto the annular collar and releases the locking arms for a spreading in its other opposite inserted locking position. 
         [0018]    It is advantageous hereby according to the invention if the release safeguard is comprised of a sleeve that encloses the sleeve section, which has locking lugs facing the outer edge in the direction of insertion and lock in recesses of the peripheral wall of the sleeve section in the corresponding locked position. 
         [0019]    The release safeguard according to the invention is characterized by a very compact space-saving design and prevents a displacement of the release safeguard before assembly of the mating plug-in connector as well as during its assembly by means of the configuration of the annular collar as oval annular in the assembly position. 
         [0020]    Other advantageous embodiments and features of the plug-in connector according to the invention are claimed in the dependent claims, wherein the features of the individual dependent claims are essential to the invention in combination with the features of the main claim and independently from each other. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    This invention will be described in further detail with the aid of the exemplary embodiments depicted in the enclosed drawings, wherein: 
           [0022]      FIG. 1  shows a perspective exploded view of the connection, according to the principles of the present invention, of a plug-in connector and a mating plug-in connector with two different depictions of the displacement safeguard; 
           [0023]      FIG. 2  shows a frontal view of an adapter sleeve embodying the principles of the present invention; 
           [0024]      FIG. 3  shows a lateral view, partially in section, of an adapter sleeve according to  FIG. 2 ; 
           [0025]      FIG. 4  shows a perspective frontal view of the adapter sleeve according to  FIG. 3 ; 
           [0026]      FIG. 5  shows a sectional view along section N-N in  FIG. 3 ; 
           [0027]      FIG. 6  shows a sectional view along section O-O in  FIG. 3 ; 
           [0028]      FIG. 6 a    shows a view of the adapter sleeve according to  FIG. 3  corresponding to arrow A in  FIG. 1 ; 
           [0029]      FIG. 7  shows a longitudinal section through the plug-in connector in the inserted state of the adapter sleeve and prior to insertion of the mating plug-in connector, according to this invention; 
           [0030]      FIG. 8  shows a sectional view in longitudinal section of a plug-in connection of the invention according to  FIG. 1  during the insertion operation of the mating plug-in connector; 
           [0031]      FIG. 9  shows a view according to arrow B in  FIG. 8 ; 
           [0032]      FIG. 10  shows a longitudinal section through the plug-in connection of the invention according to  FIG. 1  in the inserted state of the mating plug-in connector; 
           [0033]      FIG. 11  shows a view according to  FIG. 10  with the safeguard element displaced into securing position; 
           [0034]      FIG. 12  shows a perspective view of a second embodiment of the adapter sleeve according to the invention; 
           [0035]      FIG. 13  shows a frontal view of the adapter sleeve according to  FIG. 12 ; 
           [0036]      FIG. 14  shows a longitudinal section through the plug-in connection according to the invention in the uninserted state of the mating plug-in connector with an adapter sleeve according to  FIG. 12 ; 
           [0037]      FIG. 14 a    shows a view according to  FIG. 14 , but rotated by 90°; 
           [0038]      FIG. 15  shows a section corresponding to  FIG. 14 , but with a partially inserted mating plug-in connector; 
           [0039]      FIG. 16  shows a view according to arrow C in  FIG. 15 ; 
           [0040]      FIG. 17  shows a section through the plug-in connection of the invention according to  FIG. 14  in the inserted state of the mating plug-in connector; 
           [0041]      FIG. 18  shows a view according to arrow D in  FIG. 17 ; 
           [0042]      FIG. 19  shows a view, partially in section, of an alternative embodiment of a plug-in connector according to the invention; and 
           [0043]      FIG. 20  shows an enlarged view of the detail of a section F in  FIG. 15 . 
       
    
    
       [0044]    Identical parts are identified with the same reference numerals in the individual figures. 
       DETAILED DESCRIPTION 
       [0045]    In the subsequent description, it is explicitly claimed that the invention is not limited to all or several features of the described combinations, but each individual sub-feature of the exemplary embodiment can rather have inventive importance in connection with or in combination with other features, as well as also independently from the feature combinations. 
         [0046]    As shown in  FIG. 1 , the plug-in connector  1  embodying the principles of the invention has a housing  2  with a sleeve section  3  at one end. At the other end, the housing  2  has a plug-in section  4 , for example for plugging into a fluid line or a line connector. This plug-in section  4  can however also be configured as a receiving section for receiving insertion of a fluid line, for example via a releasable plug connection. The housing  2  can alternatively also be connected at the other end to a unit via such a plug connection. 
         [0047]    The plug-in connector  1  can be configured as an angular plug-in connector as shown in  FIG. 1 . The plug-in connector  1  can alternatively not be angled between the sleeve section  3  and the plug end section  4 , so that it can be configured straight, or any angles can be present between sections  1  and  4 . Also possible are T-shaped or Y-shaped plug-in connectors. The plug-in connector  1  can also be a component of a distributor housing with additional further connections for a fluid line or for a measuring connection or the like. 
         [0048]    The housing  2  has a passage channel  5 . The passage channel  5  has a channel section  6  with an especially enlarged diameter in the area of the sleeve section  3 . 
         [0049]    An adapter sleeve  7  is inserted into the sleeve section  3  with the enlarged diameter channel section  6  of the housing  2 . This adapter sleeve  7  has an opening  8 , see  FIGS. 1 and 2 . The adapter sleeve  7  furthermore has a sleeve wall  9 , which encloses the opening  8 . Locking means are configured in the sleeve wall  9  especially in two mutually diametrically opposite sections. These locking means preferably consist of two locking arms  10 , which are radially elastic with respect to a longitudinal center axis X-X of the adapter sleeve  7 . The locking arms  10  run, for example, parallel to the longitudinal center axis X-X and are separated from the sleeve wall  9  at their longitudinal sides by means of slot-shaped clearances  11 . The locking arms  10  are connected to the sleeve wall  9  at the front end of the adapter sleeve  7  in direction of insertion Z. The locking arms  10  have in this case, preferably, a lesser thickness than the wall thickness of the sleeve wall  9 , so that a stepped surface  9   a  running in the direction of the longitudinal center axis X-X is configured between the outer periphery of the sleeve wall  9  and the locking arms  10 . 
         [0050]    As can furthermore be seen in  FIG. 1 , it may be practical to configure an annular step  9   b  at the front end of the adapter sleeve  7  in insertion direction Z. Guide grooves  9   c , whose groove base rests on the same radius around the longitudinal center axis X-X as the periphery of the annular step  9   b , extend around the periphery of the adapter sleeve  7  starting from this annular step  9   b . The guide grooves  9   c  each have a widening funnel-shaped insertion opening  9   d , which expands in insertion direction Z. The guide grooves  9   c  serve to guide guiding ribs  9   e  configured along the inner wall in the interior of the channel section  6 , wherein the adapter sleeve  7  is oriented in such a way that the guiding ribs  9   e  are inserted into the guide grooves  9   c . In this way is attained a correct positioning of the adapter sleeve  7  in the channel section  6 . Four guide grooves  9   c  offset with respect to each other by 90° are preferably configured. 
         [0051]    The locking arms  10  have, for example, locking cams  12  at their free ends, which are oriented radially in the direction of the longitudinal center axis X-X. These locking cams  12  lock into a locking groove  13  of an inserted mating plug-in  14  connector with the adapter sleeve  7  inserted into the passage opening  8 ; see  FIGS. 10 and 17 . These locking cams  12  are located outside of the sleeve section  3  with the adapter sleeve  7  inserted into the sleeve section  3 . As can be seen, for example, in  FIGS. 4, 7 , the passage opening  8  has the same inner diameter over its entire length, so that a continuous smooth, step-free inner wall is present, which transfers over into an opening area located in the rear, particularly an angled insertion surface in the opening area of the passage opening  8  in insertion direction Z. 
         [0052]    It can furthermore be practical if the adapter sleeve  7  has an annular collar  15  over the periphery of its passage opening  8 , that is in an opening area located in the rear seen in insertion direction Z. This annular collar  15  runs radially outwardly offset with respect to the sleeve wall  9 , so that its outer diameter and its inner diameter are especially larger than the outer diameter of the sleeve wall  9 . The outer diameter of the annular collar  15  is suitably equally as large as that of the sleeve section  3 . 
         [0053]    The annular collar  15   a  is thus circumferentially separated from the adapter sleeve  7  by means of circumferential gap sections  32  between the locking arms  10 . The annular collar  15  is connected on its outer side via webs to the locking arms  10  in the area of the locking cams  12  of the locking arms  10 . The annular collar  15  accordingly encloses the adapter sleeve  7  in the area of the free ends of the locking arms  10 . It is advantageous according to the invention if the annular collar  15  has two diametrically opposite deformation sections  33  in the center between the locking arms  10 . In the area of the deformation sections, the annular collar  15  can be deformed radially inwardly by means of a force P to be applied radially from outside towards the longitudinal center axis X-X in such a way that the locking arms  10  are spread radially outwardly in such a way that their locking cams  12  are disengaged from the locking groove  13  of the plug shaft  14   a  of the inserted mating plug-in connector  14 ; see  FIG. 8 . The annular collar  15  adopts an oval shape as a result of this external force exerted on the deformation sections  33 ; see  FIG. 9 . Such a deformation also takes place during the insertion of the plug shaft  14   a  into the mating plug-in connector  14   a . Release of the mating plug-in connector  14  from the plug-in connector  1  is possible in this way. The outer diameter of the annular collar  15  is especially equal in size to the outer diameter of the sleeve section  3 . The deformation sections  33  are suitably formed, for example, by rib-like projections of the annular collar  15 , which are radially outwardly directed with reference to the longitudinal center axis X-X. It is practical according to the invention if the locking cams  12  have a radial distance to the longitudinal center axis X-X, which is smaller than an inner radius of the passage opening  8 . It is also of further advantage, if a radial distance of the locking arms  10  with reference to the longitudinal center axis X-X is at least equal to the inner diameter of the passage opening  8  in the area adjacent to the locking arms  12 . 
         [0054]    According to the invention, the adapter sleeve  7  is positively fixed in the axial direction and preferably also in the peripheral direction within the sleeve section  3  by means of positively locking elements. These positively locking elements consist of radially elastic locking elements  29  configured over the periphery of the adapter sleeve  7  between the locking arms  10 . 
         [0055]    The locking elements  29  are formed in particular by two radially elastically bendable arms  29   a  running axially parallel to the longitudinal center axis X-X. These arms  29   a  are arranged respectively offset by 90° with respect to each other towards the locking arms  10 . The arms  29   a  are separated by a U-shaped slot  29   b  from the wall of the adapter sleeve  7  and are connected as one piece to the wall of the adapter sleeve  7  with their end that faces opposite the direction of insertion Z; see  FIGS. 7, 8 . The arms  29   a  have locking cams  29   c , which project radially and outwardly at their free ends and also have an inclined surface  29   d  facing the direction of insertion, as well as a locking surface  29   e  extending perpendicular to the longitudinal axis X-X, which encloses an acute angle at its outer free end with the inclined surface  29   d ; see  FIG. 3 . The peripheral circle on which the locking cams  29   c  rest with their free ends has a diameter that is larger than the inner diameter of the channel section  6  of the sleeve section  3  and smaller than the outer diameter of the channel section  6 . It is practical if a bracing base  29   f  is formed behind the respective locking cams  10  seen from the direction of insertion. The thickness of the arms  29   a  is preferably less than the thickness of the wall of the adapter sleeve  7 . The spring elasticity of the arms  29   a  can be adjusted via the length and the thickness of the arms  29   a.    
         [0056]    The locking cams  29   c  correspond to recesses  30  in the peripheral wall of the sleeve section  3  in such a way that the adapter sleeve  7  in the sleeve section  3  positively engages the locking cams  29   c  in the recesses  30  with the adapter sleeve  7  inserted. The recesses  30  are advantageously configured as breakthroughs of the wall of the sleeve section  3 . Four recesses  30  arranged offset by 90° with respect to each other are preferably provided in the sleeve section  3 . The locking cams  29   c  are dimensioned in particular in such a way that their free ends do not project out of the breakthroughs  30  when inserted. The adapter sleeve  7  can be inserted in positions mutually rotated by 90° by configuring four recesses  30  that are offset with respect to each other by 90°. It is likewise within the scope of the invention if the breakthroughs  30  are configured as inner indentations, so that the peripheral wall of the sleeve section  3  is closed. Reference can be made to the exemplary embodiment (see  FIG. 19 ) with regard to this. 
         [0057]    The locking cams  29   c  engage with their locking surfaces  29   e  running perpendicularly to the longitudinal center axis X-X, and the recesses  30  have contact surfaces opposite the locking surfaces  29   e , which likewise extend perpendicularly to the longitudinal axis X-X. This configuration of the mutually opposite surfaces causes a positive locking in the axial direction when in locked state. The locking cams  29   c  and the recesses  30  are suitably adapted to each other in such a way that a twisting of the adapter sleeve  7  becomes impossible in locked state. 
         [0058]    The assembly of the adapter sleeve  7  is carried out according to the invention in such a way (see  FIG. 1 ) that first a peripheral seal  26  is inserted into the sleeve section  3 . The adapter sleeve  7  is thereafter inserted into the sleeve section  3  until the end of the locking elements  28 , that is the locking cams  29   c , are engaged in the recesses  30 ; see  FIG. 7 . In the fully assembled plug-in connector according to the invention, the plug shaft  14   a  is inserted into the mating plug-in connector  14 ; see  FIG. 8 . The locking arms  10  are spread apart as a result of this insertion (see  FIG. 8 ) and the annular collar  15  takes on an oval shape; see  FIG. 9 . This happens in such a way that its outer diameter in the area of the actuating sections  33  is smaller than that in the area of the locking cams  12 . The latter is then greater than the outer diameter of the sleeve section  3 . The locking arms  12  of the locking arms  10  positively engage in the locking groove  13  of the mating plug-in connector  14  in the inserted state of the mating plug-in connector  14  (see  FIG. 10 ), wherein the annular collar  15  again assumes its original circular shape. 
         [0059]    As can be seen in  FIGS. 1 to 11 , it may be practical according to the invention to displaceably arrange a release safeguard  60  on the outer periphery of the sleeve portion  3  in longitudinal direction of the longitudinal axis X-X. This release safeguard  60  is displaceably mounted between two positions, specifically locking positions. The first position is an assembly position, in which the mating plug-type connector  14  can be inserted into the plug-in connector  1 , and specifically into the adapter sleeve  7 ; see  FIGS. 7, 8 . The second position is a position in which the release safeguard  60  is pushed in the direction of the annular collar  15  in such a way, that the release safeguard  60  prevents a radial spreading of the locking arms  10 ; see  FIG. 11 . 
         [0060]    The release safeguard  60  according to this invention preferably consists of a sleeve  61 , which positively encloses the socket section  3 . This sleeve  61  is displaceably mounted on the sleeve section  3 , and specifically between the two aforementioned positions. In the first position, the sleeve  61  is located completely on the sleeve section  3 , so that the annular collar  15  is freely accessible and a spreading the locking arms  10  is possible by means of the vertical force P on the annular collar  15  or the locking arms  10  can alternatively be spread during the insertion of the mating plug-in connector  14 ; see  FIG. 8 . The sleeve  61  positively locks in this position, for example, with the configured locking lugs  63  configured on its peripheral edge  62 , with locking projections  64  located on their ends, that is, releasably in a recess  65  in the peripheral wall of the sleeve section  3 . Two locking lugs  63  offset with respect to each other by 180° and two recesses  65  offset with respect to each other by 90° are preferably provided. In the second position, specifically a locking position, the sleeve  61  also encloses the annular collar  15 ; see  FIG. 11 . A spreading of the locking arms  10  is hereby no longer possible, so that the undesirable release of the plug-in connection according to the invention, which consists of a plug-in connector  1  and mating plug-in connector  14 , is prevented. In this second locking position, the sleeve  61  positively locks with the locking lugs  63  in the recesses  65   a , which can coincide with the recesses  30 , that are provided in the peripheral wall of the sleeve section  3 . The sleeve  61  is suitably provided over its periphery with indentations  66 , which are designed in such a way that the protrusions  33   a  provided on the annular collar  15  reside the indentations  66 , so that a displacement of the sleeve  61  is not hindered in this second position. The indentations  66  can be configured, as represented in  FIG. 1 , as either axial indentations  66  or alternatively as radial indentations of the sleeve wall, so that in this embodiment of the release safeguard  60   a , the sleeve wall is closed on the outside and the protrusions  33   a  are completely enclosed by the indentations  66 . 
         [0061]    Four longitudinal ribs  67  that are arranged mutually offset by 90° are formed over the outer periphery of the sleeve section  3 . In adaptation thereto, the sleeve  61  is provided with guide grooves  68  in its sleeve wall for accommodating the longitudinal ribs  67 . A correct insertion of the sleeve  61  on the sleeve section  3  is obtained in this way, if the adapter sleeve  7  has not yet been introduced into the socket section  3 ; see  FIG. 1 . 
         [0062]    It can be advantageous if the annular collar has a modified shape. The annular collar  15   a  has herein an oval shape in the non-spread position of the locking arms  10 ; see  FIGS. 12, 13 , so that the outer diameter of the annular collar  15   a  in the area of the locking cams  12  is smaller than in the area of the actuating sections  33 . 
         [0063]    Its largest outer diameter is thus configured in the area of the actuating sections  33  and its smallest outer diameter is configured in the area of the locking cams  12 , and the largest outer diameter is greater than the outer diameter of the circular peripheral contour of the sleeve section  3 , and its smallest external diameter is smaller than the outer diameter of the sleeve section  3 . 
         [0064]    The outer diameter of the annular collar  15   a  is hereby greater than the outer diameter of the sleeve section  3  in the area of the actuating sections  33 . The radial distance of the locking arms  10  in the area of the locking cams  12  is smaller than the inner diameter of the passage opening  8  in the unassembled state; see  FIGS. 14, 14   a . The locking arms  10  positively engage hereby in the locking groove  13  of the mating plug-in connector when the plug-in connector is inserted (see  FIG. 17 ), on the one hand, and the locking arms  10  are spread in such a way during insertion of the mating plug-in connector  14  with its plug shaft  14   a , on that other hand, that the annular collar  15   a  assumes an opposite oval peripheral contour, wherein the outer periphery of the annular collar  15   a  projects with respect to the outer periphery of the sleeve section  3 , and specifically in the area of the locking cams  12 ; see  FIGS. 15, 16 . The radial distance of the locking arms  10 , including the locking cams  12 , is dimensioned in such a way when locked in the locking groove  13 , that the annular collar  15   a  has a circular shape that is such that its outside diameter is smaller than/equal to the outer diameter of the sleeve section  3 ; see  FIGS. 17, 18 . The configuration of the annular collar  15   a  makes possible that in the unassembled position of the mating plug-in connector  14  (see  FIG. 14 a   ) and during the insertion of the mating plug-in connector into the adapter sleeve  7  (see  FIG. 15 ), the sleeve  61 ,  61   a  cannot be displaced over the annular collar  15   a , but can be displaced over the annular collar  15   a  into its second position in the inserted state of the mating plug-in connector  14 ; see  FIG. 17 . The oval configuration of the annular collar  15   a  thus makes possible, as described above, a double safeguard for the plug-in connection against the undesirable displacement of the sleeve  61  and release of the mating plug-in connector  14  from the plug-in connector  1  according to the invention. 
         [0065]    A connection section  24  of the mating plug-in connector  14  can be configured as a connection sleeve for the inserting or screwing-in of a fluid line port or another connector part; see  FIG. 1 . The connection section  24  can alternatively also be used as a connection pin to plug in a fluid line. 
         [0066]    A fluid channel  34 , which suitably has an inner channel diameter that corresponds to the inner diameter of the passage channel  5  of the housing  2 , runs through the mating plug-in connector  14 . 
         [0067]    The mating plug-in connector  14  has a plug shaft  14   a  with a circular cross section perpendicular to its center axis. The outer diameter of the plug shaft  23  is greater than a radial distance of the locking cams  12 , so that the locking arms  10  are bent radially outwardly during insertion of the plug shaft  23 ; see regarding this  FIGS. 8, 15 . The connector shaft  23  is provided with the circumferential locking groove  13  at its front end in the direction of insertion Z. This locking groove  13  has a front contact surface that extends perpendicularly to the center axis X-X, and a contact surface, which contacts with a contact surface of the locking cam  12 , which is likewise perpendicular to the longitudinal axis X-X, in such a manner that a positive locking is obtained in the locked state in the axial direction, so that an autonomous release of the connector pin or the plug shaft  14   a  cannot occur under tensile stress. The connection section  24  is provided at the end of the mating plug-in connector  14  opposite the plug-in shaft  14   a  for connection of a fluid line or a unit. An annular shoulder, which can serve as stop, is formed between the connection section  24  and the locking groove  13 . The length of the plug shaft  14   a  is especially dimensioned in such a manner that it extends with its free end into the adapter sleeve  7 , and from the adapter sleeve  7  to the passage channel  5  of the housing  2  in the inserted state. 
         [0068]    It is furthermore suitably provided according to the invention (see  FIG. 20 ) that the peripheral seal  26  is arranged ahead of the adapter sleeve  7  within the sleeve section  3  in direction of insertion Z. This peripheral seal  26  seals the peripheral gap between the plug shaft  14   a  in its inserted state and is encased between an annular shoulder  27  at the transition of the sleeve section  3  and a front end surface  6   a  of the adapter sleeve  7 . A receiving groove for the peripheral seal  26  can be omitted because of this embodiment according to the invention, so that the configuration of undercuts is not required in terms of manufacturing technology. The peripheral seal  26  is moreover protected in the interior of the sleeve section  3  in the assembled state of the adapter sleeve  7 . The inner diameter of the passage throughflow channel  5  of the housing  2  and the inner diameter of the passage opening  8  of the adapter sleeve  7  are adapted to the outer diameter of the plug shaft  14   a  of the mating plug-in connector  14 . The inner diameter of the throughflow channel  5  and the passage opening  8  suitably have the same size. As a result of an elastic deformation of the sealing ring  26 , which is caused by the insertion of the plug shaft  14   a , takes place, on the one hand, a sealing to the outside and, on the other hand, a fixation of the plug shaft  14   a  in the adapter sleeve  7  or in the sleeve section  3  by means of the deformation stress generated inside the O-seal. The annular step  9   b  of the adapter sleeve  7  has a circumferential contact surface  27   a  that runs radially to the longitudinal center axis X-X. As shown in  FIG. 20 , in particular the channel section  6  has an annular-shaped stop surface  27   b  configured in the sense of a diameter enlargement, which is arranged in such a way that the peripheral seal  26  runs between the annular shoulder  27  and the stop surface  27   b . The adapter sleeve  7  with its contact surface  27   a  rests against the stop surface  27   b  in the inserted state, and the adapter sleeve  7  projects with its annular step  9   b  into the section  6   a  of the channel section  6 , which is sealed by means of the peripheral seal  6  [ 26 ]. 
         [0069]    A geometric termination of the receiver for the peripheral seal  26 , a boundary for the plug-in path during assembly of the adapter sleeve  7 , a reception and further forwarding of the spreading force as well as a maintaining of a gap between the sleeve section  3  of the housing  2  and of the adapter sleeve  7  take place as a result of the preceding embodiment. 
         [0070]    It is furthermore advantageous according to the invention if a radially directed stop surface  27   c  is configured in the interior of the passage bore  6  behind the annular shoulder  27  in the sense of a diameter reduction, whereby a depth stop  27   c  is created; see  FIGS. 7, 8 . 
         [0071]    As shown in  FIGS. 8, 9 and 15, 16 , the annular collar  15 ,  15   a  with its sections that are connected to the locking arms  10  projects radially outwardly if the mating plug-in connector  14  is not yet fully inserted, so that the annular collar  15 ,  15   a  acquires an oval shape. A visual control as to whether the locking position has been achieved or not is thus provided. When in locking position, the annular collar  15  closes flush with its outer periphery with the outer periphery of the sleeve section  3 , wherein the annular collar  15 ,  15   a  has then a circular peripheral contour. 
         [0072]    In  FIG. 19  is depicted an embodiment of the plug-in connector  1 , which shows a production by metal cutting. The recesses  30  are not realized hereby as breakthroughs, but rather form a peripheral edge that effects an axial fixing of the adapter sleeve  7 . A twisting of the adapter sleeve  7  is however possible. 
         [0073]    It is furthermore advantageous according to the invention if the radial height of the stepped surface  9   a  and the length of the locking arms  10  within the sleeve section  3  is dimensioned in such a way that the radial distance of the locking cams is smaller than the inner diameter of the adapter sleeve  7  and smaller than the outer diameter of the plug shaft  14   a  of the mating plug-in connector  14 . 
         [0074]    The present invention also relates to a plug-in coupling consisting of a plug-in connector  1  and a mating plug-type connector  14 , such as described above. 
         [0075]    Furthermore, as can be seen in  FIG. 1 , it is practical according to the invention if two diametrically opposite receiving pockets  2   a  at are configured at the transition of the sleeve section  3  into the remaining plug-in connector housing  2 . These receiving pockets  2   a  serve for accommodating the gripping devices for the assembly of the plug-in connector  1  according to the invention. 
         [0076]    The invention is not limited to the depicted and described exemplary embodiments, but also comprises all equally effective embodiments in the sense of the invention. It is explicitly emphasized that the exemplary embodiments are not limited to all features in combination, but that rather each individual partial feature can have inventive importance by itself independently from the others. The invention is moreover also not limited to the feature combination defined in claim  1 , but can also be defined by any other combination of specific features of all overall disclosed individual features. This means that, in principle, virtually each individual feature of claim  1  can be omitted or substituted by at least an individual feature disclosed at another point of the application.