Abstract:
A plug connector for media-bearing lines has a plug body for connecting to an opening. At least one rib is provided on the plug body, the rib being retained in the opening in the assembly position of the plug body by a retaining clip adjustable on the plug body. An assembly force acts on the retaining clip, the clip being supported on at least one rib of the plug body, thereby displacing the plug body into the opening, and locking therein in an undercut.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a 35 USC 371 application of PCT/EP 2010/058772 filed on Jun. 22, 2010. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a plug connector for media-bearing lines. The plug connector has a plug body for connecting to an opening. 
     2. Description of the Prior Art 
     German Patent Disclosure DE 199 15 695 A1 relates to an inlet element of plastic and a method for its production. A throttle body includes an inner primary portion of plastic as well as a secondary portion of plastic, which is formed cohesively with an outer circumference of the primary portion, as well as an icing-prevention tube, which is embedded in the secondary portion. The cylindrically configured primary portion, with an essentially uniform wall thickness, is formed in a first molding step, as a result of which there is less shrinkage and rejection. Hence the requisite roundness or circularity of an inner circumferential face of the primary portion is ensured. The secondary portion is formed in an ensuing, second molding step, so that an outer side of the primary portion is covered in order thereby to produce a throttle body having a desired geometry. The temperature of a portion of the molding tool, which points toward the inner circumferential surface of the primary portion, is set lower than the temperature of the other portion of the molding tool, as a result of which the inner circumferential face of the primary portion, where dimensional precision is critical, can be cooled sooner than the other portion, to prevent shrinkage. If different types of plastic material are used for forming the primary and secondary portions, the degree of freedom in terms of the choice of material is increased. 
     German Patent Disclosure DE 39 07 764 A1 has a fuel distributor for fuel injection systems of internal combustions as its subject. This fuel distributor for fuel injection systems, having at least one fuel injection valve with a valve holder, has a receiving bore for the fuel injection valve and an end flange surrounding the receiving bore. The fuel injection valve is supported on the end flange by means of a collar. For positional fixation of the fuel injection valve, the end flange of the valve holder and the collar of the fuel injection valve are embodied, independently of a plug hood that is still to be put on, as parts corresponding to one another of a bayonet mount. The plug hood is used as an additional locking means and for that purpose, with locking pegs, it engages the recesses, serving the purpose of locking and unlocking, in the bayonet mount in form-locking fashion. 
     German Patent Disclosure DE 102 40 130 A1 relates to a plug connector for media-carrying lines. A method is disclosed with which a plug connector can be produced that has at least one connection point. A sleevelike body is injection-molded from a first material. The sleevelike body obtained is placed in a further cavity. In the further cavity, a plug body of a second material is injection-molded. The sleevelike body placed in the further cavity forms the molding tool, in some regions, for the plug body. 
     German Patent Disclosure DE 10 2006 061 952 A1 discloses a plug connector for media-carrying lines. The plug connector serves in particular for securing in an opening of an injector body of a fuel injector with a plug body. At least one detent element is embodied on the plug body. The plug body includes a connection stub, and the at least one detent element, in a locking position of a retaining clip received displaceably on the plug body, is secured in the opening of the injector body. 
     ADVANTAGES AND SUMMARY OF THE INVENTION 
     According to the invention, in a plug connector, it is proposed that the capability of assembling a plug body in an opening be improved. With the provisions according to the invention, for instance when a low-pressure-side return of a fuel injector is connected by means of the plug connector, the assembly steps of placing the plug body on the fuel injector and the ensuing locking of the plug body in the opening be combined, thus precluding incorrect assembly. This is achieved by providing that in the plug connector proposed according to the invention, compulsory guidance takes place, and thus correct placement of the plug connector on a connection stub in the low-pressure region of a fuel injector is ensured. Any possible escape of fuel from incorrect assembly can be reliably avoided by means of the plug connector proposed according to the invention. 
     Advantageously, the provisions proposed according to the invention make it possible to shorten the assembly or cycle times in the assembly of a fuel injection system in internal combustion engines. The separate assembly steps, that is, the placement and subsequent locking of the plug body on a connection stub of a fuel injector, are combined in one motion as a result of the compulsory guidance. The introduction of force to enable the assembly takes place at only a single point, and the two assembly steps are automatically performed sequentially one after the other. 
     The provisions proposed according to the invention make it possible to further reduce the amount of space required, so that the freedoms in terms of assembling the plug connectors proposed according to the invention in an internal combustion engine are improved. Moreover, because of the provisions proposed according to the invention, the line course can be simplified and the connection of surrounding engine components or components of the fuel injection system can be improved. 
     By means of an especially advantageous central force introduction, assembly faces become superfluous and can be dispensed with entirely. Because of a reduction in the use of material, economy of material and an attendant cost reduction can be ensured. 
     The provisions proposed according to the invention are furthermore suitable for automated checking whether a return plug is correctly connected; this is done via a pin, to be provided centrally on the plug body, that plunges through the end face of the retaining clip, and the clip is movable relative to the plug body of the plug connector. If the return plug body is correctly assembled, the end face of the retaining clip is located in the same plane as lands that are integrally injection-molded laterally onto the plug body, so that correct assembly of the plug body as well as the correct position of the retaining clip in a locked point can be detected automatically or mechanically. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in further detail below in conjunction with the drawings. In the drawings: 
         FIG. 1  shows the plug connector proposed according to the invention in the open position, before assembly on the low-pressure-side return of a fuel injector; 
         FIG. 1A  is an enlarged view of the contact region between touch hooks of a retaining clip and ribs of a plug body of the plug connector; 
         FIG. 2  shows the retaining clip on the plug body in the open position; 
         FIG. 2A  is a view on a larger scale of the spread-apart detent hooks; 
         FIG. 2B  is a detail showing contoured contact faces of detent hooks and of ribs of the plug body; 
         FIG. 3  shows the plug body, introduced into the opening of a bushing, but not yet locked; 
         FIG. 4  is a view of the ribs of the plug body, subjected to the assembly force before the rib heads snap into a recess of the bushing; 
         FIG. 5  shows the heads of the ribs, latched in a recess, extending in the circumferential direction, of the bushing; 
         FIG. 6  shows a plug body of a return plug, the plug body having been inserted farther into an injector outlet stub; 
         FIG. 6A  is a detail view of the contoured face ends, contacting one another, of ribs of the plug body and of detent hooks of the retaining clip; 
         FIG. 7  shows the radially inward sliding of the contoured face ends of the detent hooks away from the heads of the ribs of the plug body; 
         FIG. 8  shows the retaining clip, inserted into the injector stub, in the assembly position; 
         FIG. 9  shows the assembled state of the plug connector proposed according to the invention, in an outlet stub of a fuel injector, the stub being located in the low-pressure region; and 
         FIG. 10  is a perspective view of the retaining clip. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     From the view in  FIG. 1 , it can be seen that a plug connector  10  includes both a plug body  12  and an injector stub  14  or a bushing  70 . On the plug body  12 , spaced apart by 180° or 120° from one another, are a first connection  16  and a second connection  18 , which together form a horizontal conduit  52 ; see the views in  FIGS. 2 ,  6 ,  7 ,  8  and  9 . 
       FIG. 1  shows the plug connector proposed according to the invention, with a plug body, in the open position before assembly in an injector stub on the low-pressure side of a fuel injector. 
     From the view in  FIG. 1 , it can be seen that a plug connector  10  includes both a plug body  12  and an injector body  14  or a bushing  70 . On the plug body  12 , spaced apart by 180° or 120° from one another, are a first connection  16  and a second connection  18 , which together form a horizontal conduit  52 ; see the views in  FIGS. 2 ,  6 ,  7 ,  8  and  9 . 
     An essentially vertically movable retaining clip  22  is received on the plug body  12 . The retaining clip  22 , preferably like the plug body  12  made as an injection-molded component, includes an end face  24 . The end face  24  is engaged by an assembly force F, indicated by reference numeral  20 , with which the retaining clip  22  is movable in the assembly direction  38 . 
     The retaining clip  22  is disposed movably relative to the plug body  12 . The retaining clip  22  includes detent hooks  26 , for instance two of them, facing one another. The detent hooks  26  extend with a spread  64  on the retaining clip  22 ; see the views in  FIGS. 2A and 2B . 
     On one of the detent hooks  26 , there is a tonguelike positioning aid  28 , which can be made directly by plastic injection casting in the production of the retaining clip  22 . The positioning aid  28  is embodied such that it moves into a first slot  30  on the circumference of the plug body  12  in the vicinity of a rib  44 . Next to the first slot  30 , which extends essentially in the vertical direction on the plug body  12 , a further, wider, second slot  32  is provided in the plug body  12 , but it is not penetrated by a positioning aid  28 . The second slot  32  is located between the jacket face of the plug body  12  and the other side face of the rib  44 . 
     Also located on the retaining clip  22  having the two facing detent hooks  26  are support faces  36 , with which the retaining clip  22 , for locking the plug body  12 , rests on an end face of an opening  40  of the injector stub  14  or of the bushing  70 . 
     The plug body  12  of the plug connector  10  proposed according to the invention furthermore has support faces  34 , with which the plug body  12 , in the state inserted into the opening  40 , rests on the face end of the injector stub  14  that defines the opening  40 , or on the end face of the bushing  70  (see  FIGS. 8 and 9 ). 
     From the perspective view in  FIG. 1 , it can furthermore be seen that ribs  44  are embodied on the plug body  12 , extending oppositely in the vertical direction to the detent hooks  26  of the retaining clip  22 . The assembly direction  38  in which the plug connector  10  proposed according to the invention is assembled in the opening  40  is indicated by reference numeral  38 . 
       FIG. 1A  shows a view of the region where the detent hooks  26  of the retaining clip  22  contact the ribs  44 . The ribs are integrally injection molded onto the jacket face of the plug body  12  of the plug connector  10  proposed according to the invention. 
       FIG. 1A  shows that the positioning aid  28 , integrally injection molded on a contact face  42  on the face end of the detent hook  26 , is embodied in essentially tonguelike fashion. The tonguelike positioning aid  28 , which prevents twisting of the retaining clip  22 , protrudes into the first slot  30  between the jacket of the plug body  12  and a lateral boundary face of the rib  44 . In the assembled state in  FIG. 1A , the retaining clip  22 , on which the detent hooks  26  are embodied, is in its open or in other words still unlocked position, and it can also be seen from the view in  FIG. 1A  that the contact face  42  is located at a distance, although slight, from the upper edge of the rib  44 . 
       FIG. 2  shows a view of the plug connector proposed according to the invention, with a retaining clip that has stayed in the open position. 
       FIG. 2  shows that in the open position of the retaining clip  22 , the retaining clip is locked with a groove  48  in a corresponding tongue  46  of the plug body  12  of the plug connector  10 . The groove  48  and the tongue  46  form a restraint device  45  for the retaining clip  22 . The detent hooks  26  of the retaining clip  22  extend with a spread—see reference numeral  64  in  FIGS. 2A and 2B . It is can be seen from the view in  FIG. 2  that the plug body  12  of the plug connector  10  proposed according to the invention is introduced into the opening  40  of the injector stub  14  or of the bushing  70 . The ribs  44 , extending oppositely to the detent hooks  26  of the retaining clip  22 , are located on the jacket face of the cylindrically embodied plug body  12 . The plug body  12  is preferably made in the course of the plastic injection-molding process, and besides the connections  16  and  18  and the horizontal conduit  52  formed by them, it has a vertically extending vertical conduit  50 . Moreover, a recess  68 , embodied as an encompassing groove, is located on the end of the plug body  12  pointing toward the opening  40 , and a seal  66 , embodied in particular as an O-ring, is let into this recess. 
     It can be seen from the view in  FIG. 2  that because of the action of the restraint device  45 , the detent hooks  26  of the retaining clip  22  are brought just far enough toward the top of the ribs  44  of the plug body  12  that the face ends of the detent hooks  26  and the face ends of the ribs  44  still just barely do not touch. Guide rails  96 , embodied on the inside of the retaining clip  22 , slide in recesses  98 , embodied in complementary fashion to the profile of the guide rails, on the plug body  12  in order to prevent tilting of the retaining clip  22  during assembly. Reference numeral  36  indicates the support face on the retaining clip  22 . Reference numeral  34  indicates a support face on the plug body  12 , with which, in the assembled state, the plug body rests on the face end of the injector stub  14  or of the bushing  70 . The plug body  12  is introduced into the opening  40  in the assembly direction  38 . For locking the plug body  12  in the opening  40 , the retaining clip  22  is displaced in the vertical direction.  FIG. 2  also shows that the tongues  46  of the restraint device  45 , in the open position of the retaining clip  22 , are located on the plug body  12  on the lower end of grooves  48  in the retaining clip  22 . 
       FIG. 2A , on a larger scale, shows a view of the end faces, facing one another, of both the detent hooks of the retaining clip and of the end face of the ribs of the plug body. 
     From  FIG. 2A , it can be learned that the detent hooks  26  of the retaining clip  22 , which is not shown in complete form here, are disposed with a spread  64  from one another. The spread can be in the range between 0° and 30° , depending on the dimensions. From the larger-scale view in  FIG. 2A , it can be seen that the detent hooks  26 , on one end toward a head  60  of the ribs  44 , have a contoured face end  54 . In complementary fashion to the contouring of the contoured face end  54  of the detent hooks  26 , the face ends  56  of the heads  60  of the ribs  44  are also provided with contouring. From the view in  FIG. 2A , it can be seen that the tonguelike positioning aid  28  is indicated, located behind the left detent hook  26 . In  FIG. 2A , reference numeral  58  indicates vertically extending recesses of the slots by which the resiliently embodied ribs  44  are movable relative to the jacket face of the plug body  12 . Because of the contoured face ends  54  and  56  of the detent hooks  26  and of the heads  60  of the ribs  44 , a reduction in the spread  64  of the detent hooks  26  of the retaining clip  22  is achieved upon contact of the face ends  54 ,  56  with one another. The detent hooks  26  are bent in the direction of the axis  74 . With guide rails  96  shown in  FIG. 2 , the retaining clip  22  is slid on the plug body  12  in counterpart elements embodied as recesses  98 , shaped in complementary fashion to the profile of the guide rails, in order to prevent tilting of the retaining clip  22  during its assembly or during the execution of the closing operation. 
       FIG. 2B  shows the contoured face ends  54  and  56 , contacting one another, of the detent hooks  26  of the retaining clip  22  and of the heads  60  of the ribs  44 . The contoured face ends  54  and  56  are embodied with chamfers  62  extending radially inward, so that the introduction of the detent hooks  26  into the essentially vertically extending recesses  58  or slots  58  of the plug body  12  is simplified, and an introduction of the detent hooks  26  of the retaining clip  22  into the recesses  58  or slots  58  ensues in compulsory fashion with the exertion of the assembly force  20  on the face end  24  of the retaining clip  22  (see  FIG. 2 ). 
     From the view in  FIG. 2B , it can be seen that the heads  60  of the ribs  44  have the chamfer  62  on their outside. The chamfer  62 , here embodied as a bevel, can also be embodied as a rounded area and serves to simplify the disassembly of the rib heads  60  from an undercut  72 , embodied in complementary fashion to the geometry of the rib heads, in the injector stub  14  or in the bushing  70 . 
     From the view in  FIG. 3 , the plug body—shown schematically here—can be seen in a position inserted partway into the opening. 
     When the assembly force  20  (see F in  FIG. 1 ) is exerted on the retaining clip  22 , the detent hooks  26  embodied on it, and for instance disposed facing one another, exert an inward insertion face on the heads  60  of the ribs  44  of the plug body  12 . As a result, the plug body  12  is inserted into the opening  40  in the injector stub  14  or bushing  70 . On the inside of the boundary wall of the opening  40  of the injector stub  14  or bushing  70  is the undercut  72 , which is embodied as complementary to the external geometry of the heads  60  of the ribs  44 . On the injector stub  14  or bushing  70 , a radially inward-protruding encompassing protrusion  76  extends above the undercut  72 . Reference numeral  74  indicates the axis of symmetry of the plug body  12  of the plug connector  10  proposed according to the invention. From  FIG. 3 , it can be seen that the essentially vertically oriented recess  58  or a slot  58  extends between the jacket face of the plug body  12  and the inside of the rib  44  and lends the rib  44  elasticity in the radial direction. 
       FIG. 4  shows that upon insertion of the plug body  12  into the opening  40  of the injector stub  14  or bushing  70 , or in other words when the assembly force  20  is maintained, a radially inward deflection of the head  60  of the rib  44  takes place, in accordance with the arrow marked by reference numeral  78 . The elasticity of the rib  44 , upon contact between the rib head  60  and the protrusion  76 , causes the rib head  60  to be deflected radially inward and on being inserted farther inward it latches in the direction of [or “onto”—but that doesn&#39;t make sense] the undercut  72  extending on the inside of the bushing  70  or the injector stub  14 . This state is shown in detail in  FIG. 5 . In the view in  FIG. 4 , the external geometry of the rib head  60 , when the assembly force  20  is maintained, slips in the assembly direction  38  along the protrusion  76  until the head  60  of the rib  44 , because of the intrinsic elasticity of the rib  44 , snaps into the undercut  72 , and the plug body  12  is thus fixed relative to the injector stub  14  or the bushing  70 . 
       FIG. 5  shows that because of the geometry of the contoured face end  54  and  56  (see  FIGS. 2A ,  2 B) of the detent hooks  26  and ribs  44 , respectively, on the plug body  12 , the detent hooks  26  are deflected radially inward counter to the spread  64 , corresponding to an inward insertion distance  80 , they move into the recesses  58  between the jacket face of the plug body  12  and the ribs  44 . In the state shown in  FIG. 5 , an overlap  82  of the contoured face ends  54  of the detent hooks  26  by the head  60  of the ribs  44  occurs. The overlap  82  moreover, because of the thickness of the material of the detent hooks  26 , causes the head  60  of the radially elastically embodied rib  44  to remain fixed inside the undercut  72  of the bushing  70  or injector stub  14 . The detent hooks  26  of the retaining clip  22  can plunge either partway or completely into the recesses  58  between the inside of the rib  44  and the jacket face of the plug body  12 . If the detent hooks  26  plunge only partway inward, then even if dirt accumulates in the recesses  58 , secure locking of the retaining clip  22  can still be achieved. This is all the more true if the detent hooks  26  have plunged all the way into the recesses  58 . 
     From  FIGS. 6 and 6A , the plug connector proposed according to the invention can be seen in the state in which the face ends, provided with a contour, of the detent hooks of the retaining clip just barely do contact the face ends, opposite them and contoured in complementary fashion to them, of the ribs of the plug body. 
       FIG. 6  shows that upon a motion of the retaining clip  22  in the assembly direction  38 , by the exertion of an assembly force F on the face end  24 , the detent hooks  26  rest with their face ends on the face ends of the ribs  44  on the circumference of the plug body  12 . The first connection  16  and the second connection  18  can be seen on the plug body  12 , facing one another—in this case with a 180° spacing apart from one another. They form the horizontal conduit  52  extending through the plug body  12 . The support face, which limits the maximum inward insertion distance of the retaining clip  22 , which is supported displaceably on the plug body  12 , is indicated by reference numeral  36 . The further support face  34  is embodied fixedly on the plug body  12 , and with it the plug body  12  in the assembled state rests on the periphery of the opening  40  of the injector stub  14  or bushing  70 . From the view in  FIG. 6 , it can be seen that on the detent hook  26  located in the plane of the drawing, the tonguelike positioning aid  28  has moved into the first slot  30  next to the rib  44 , while the further, second, slotlike recess  32  remains open. Because of the two recesses  30  and  32 , which extend essentially vertically next to the rib  44 , the rib  44  acts as a cradle. 
     From  FIG. 6A , it can be seen that in this enlarged view, the contoured face end  54  of the detent hook  26  rests on the complementary contoured face end  56  of the rib  44 . Because of the oriented contour, that is, a chamfer inward toward the plug body  12 , when an assembly force is applied to the retaining clip  22  in the assembly direction  38 , it is attained that the contoured face ends  54  of the detent hooks  26  slide away inward and move into the slotlike recesses  58  ( FIGS. 3-5 ). From the enlarged view in  FIG. 6A , it can be seen that the tonguelike positioning aid  28  has moved into the first slot  30 . Also from the enlarged view in  FIG. 6A , it can be seen that the rib  44  has the chamfer  62 , which in the assembled state of the retaining clip  22  acts as its bracing face to prevent it from slipping out of the undercut  72 . 
       FIG. 7  shows the retaining clip, received displaceably on the plug body, in its open position. 
     From the view in  FIG. 7 , it can be seen that the plug body  12  has been let at least partway into the opening  40  of the injector stub  14  or bushing  70 , but the retaining clip  22  is not yet locked. In the open position, shown in  FIG. 7 , of the retaining clip  22 , the retaining clip is locked on the plug body  12  in its open position by a tongue-and-groove arrangement  46 ,  48  that forms the restraint device  45 . In the open position of the retaining clip  22 , the contoured face ends  54  of the detent hooks  26  just touch the contoured face ends  56  of the ribs  44 , or heads  60  of the ribs, facing them. If the assembly force  20  acts on the end face  24  of the retaining clip  22 , then on the one hand the plug body  12  can be inserted into the opening  40  until the heads  60  of the ribs  44  rest on the periphery of the opening  40  in the injector stub  14  of the bushing  70 . 
     Correct guidance of the retaining clip  22  on the plug body  12  is attained by means of the positioning aid  28 , which in the present exemplary embodiment is embodied in tonguelike fashion. From the view in  FIG. 7 , it is seen that in the open position of the retaining clip  22  on the plug body  12 , the two, detent hooks  26  have the spread  64 . The spread  64  has the effect that the contoured face ends  54  rest precisely on contours of the face ends  56 , contoured in complementary fashion to them, on the top of the heads  60  of the ribs  44 , and the spread, indicated by reference numeral  64 , radially inward of the detent hooks  26  on the one hand and of the rib heads  60  on the other is possible. 
     From  FIG. 7  it can be seen that in complementary fashion to the geometry of the detent hooks  26  of the retaining clip  22 , the ribs  44  are disposed facing one another on the plug body  12 , and the vertically oriented slotlike recesses  58  are provided between the inside of the ribs  44  and the jacket face of the plug body  12 . 
     Reference numeral  50  indicates the vertical conduit extending through the plug body  12 , while reference numeral  52  indicates the horizontal conduit, which merges with the first connection  16  and the second connection  18  of the plug body  12  as shown in  FIG. 6 . 
     In the open position in  FIG. 7 , it can be seen that the support face  36  of the retaining clip  22  and the support face  34  of the plug body  12  are located in two different planes. In the assembly position, shown in  FIGS. 8 and 9 , of the plug connector  10  proposed according to the invention, the two support faces  34  and  36  are located in the same plane. 
     The assembly of the retaining clip  22  and of the plug body  12  in the opening  40  of the injector stub  14  or the bushing  70  takes place based on the view in  FIG. 7 . They are inserted together into the opening  40 . As seen from  FIG. 7  (see also  FIGS. 3 ,  4  and  5 ), the detent hooks  26  of the retaining clip  22  rest with their contoured face ends on the rib heads  60 , and in particular on the contoured face ends  56  of the rib heads  60 . If the rib heads are seated with their chamfers  62  on the plane face of the periphery of the opening  40 , and the assembly force  20  continues to be exerted on the end face  24  of the retaining clip  22 , then (see  FIGS. 4 and 7 ) a deflection of the detent hooks  26  of the retaining clip  22  takes place inward in the deflection direction  84 , so that the contoured face ends  54  of the detent hooks  26  slide radially inward away from the rib heads  60 . The contoured face ends  54  of the detent hooks  26  thus enter the slotlike recesses  58  extending in the vertical direction. The guide rails  96 , guided in the counterpart elements embodied as recesses  98 , on the inside of the detent hooks  26  of the retaining clip  22 , together with the positioning aid  28 , prevent tilting of the retaining clip  22  during the assembly and in the closing operation thereof. In the closing operation of the retaining clip  22 , the grooves  48  are moved relative to the tongues  46  of the restraint device  45  of the plug body  12 , until the retaining clip  22  rests with its support face  36  on the periphery of the opening  40 . 
       FIGS. 8 and 9  show that in this state, the detent hooks  26  force the rib heads  60  with their outer contour into the undercut  72  of the injector stub  14  or the bushing  70 . The result is the overlap  82 , with which the inside of the rib heads  60  cover the tips of the detent hooks  26 , so that the plug body  12 , in the assembly position, as seen in  FIGS. 8 and 9 , is received in captive fashion and locked in the injector stub  14  or bushing  70 . 
     Unlike the situation in  FIG. 6 , from  FIGS. 8 and 9  it can be seen that when assembly is complete and correct, the support face  34  of the plug body  12  is flush with the support face  36  of the retaining clip  22 , in the assembly position  90  of the plug connector  10  proposed according to the invention. Both faces  34  and  36  rest on the periphery of the opening  40 , in particular on the injector stub  14  or the bushing  70 . From  FIG. 8 , it can also be seen that lands  86  which have the hose support faces  88  are embodied on the plug body  12 . The hoses, for instance of a return system of a fuel injection system, are inserted onto the chamfered connections  16  and  18  and are widened by the cone and are thus secured to the connections  16 ,  18 . The hoses are slipped axially on until the face ends of the hoses touch the hose support faces  88  of the lands  86  of the plug body  12 .  FIG. 8  shows that when the plug connector  10  is correctly assembled, the end face  24  of the retaining clip  22  is located in the same plane as the lands  86  of the plug body  12 . In the end face  24 , there is a bore, and on one of the lands  86  there is a pin that can plunge into the bore in the end face  24 . This has not been shown in the drawing. Because it is provided, it is possible to detect the flush location of the end face  24  in comparison to the lands  86 , and thus the correct assembly position of the plug connector and of the retaining clip  22  can be checked in automated fashion or mechanically. 
     From  FIG. 9  it can be seen that in the assembly position  90 , there is a support  94  between the support face  36  of the retaining clip  22  and the periphery of the opening  40 . Reference numeral  92  indicates a sealing point in which the deformed seal  66  contacts the inside of the opening  40  in the injector stub  14  or bushing  70  and seals it off from the escape of a medium, such as fuel. 
     The position in which the support face  36  is integrally injection-molded onto the outer circumference of the retaining clip  22  determines the maximum inward insertion distance by which the detent hooks  26  of the retaining clip  22  can be inserted into the essentially slotlike recesses  58  between the inside of the ribs  44  and the circumferential surface of the plug body  12 . 
     The plug connector  10  proposed according to the invention, which is described above in terms of one exemplary embodiment shown in  FIGS. 1 through 9 , has the assembly function, and the plug connector  10  is designed in particular to be capable of being removed. Easier dismantling is possible because of the chamfers  62 . The flexibly embodied detent hooks  26  secure the plug body  12  against coming loose from the injector stub  14  or the bushing  70 . The sealing function of the sealing point  92  is taken on by the sealing ring of the seal  66 . The retaining clip  22  prevents the ribs  44  from snapping backward and thus increases the force that is required to remove the plug body  12  from the injector stub  14  or bushing  70 . 
     In  FIGS. 6 and 7 , the retaining clip  22  is latched by the restraint device  45  in an open position, in which the retaining clip does not hinder the bending of the detent hooks  26  and does not block them. In the open position, the unit, that is, the plug connector  10  and plug body  12 , retaining clip  22  and seal  66 , is assembled in the opening  40  of the injector stub  14  or bushing  70 . The lower limit of the assembly force  20  is determined on the basis of the compressive force required for compressing the sealing ring of the seal  66 . The upper limit of the assembly force  20  is determined from the lower limit of the force needed to release the retaining clip  20  on the plug body  12 . The retaining clip  22  is disposed displaceably on the plug body  12 . When the assembly force  20  is exerted, the ribs  44  of the plug body  12  are elastically deformed and latch into the undercut  72  of the injector stub  14  or bushing  70  and thus lock the plug body  12  in the opening  40 . This means that the assembly force  20  must be at least great enough to cause the deformation of the ribs  44 . The detent hooks  26  embodied as cradles are introduced in compulsory fashion into the undercut  72  by the geometry of the opening  40 . 
     Upon further exertion of the assembly force  20  in the assembly direction  38 , the retaining clip  22  is displaced on the plug body  12  such that it fits over the detent hooks  26  of the retaining clip having the rib heads  44 —see position  82  in FIG.  5 —so that the rib heads  60  are secured by the undercut  72 . The retaining clip  22  latches in assembly position  90  in such a way that it is impossible to release the retaining clip  22  without exerting force. 
     The assembly is effected via the force introduction  20  oriented in the assembly direction  38 ; only the amount of this force varies over the course of the assembly motion. The plug body  12  with the retaining clip  22  received on it is inserted into the opening  40 . The transfer of force from the retaining clip  22  to the plug body  12  can be either force-locking or form-locking, or a combination of the two. In a force-locking connection between the plug body  12  and the retaining clip  22 , interfering geometries, such as of the restraint device  45 , which can be elastically deformed via the introduction of force, are moved relative to one another. The design of the restraint device  45  is done taking friction into account; the assembly force  20  and the sealing force are adapted to one another. 
     When the plug connector  10  is correctly assembled, for instance on a fuel injector—see FIGS.  8  and  9 —and after closure of the retaining clip  22 , the end face  24  of the retaining clip  22  is located in the same plane as the two lateral lands  86  that form hose support faces  88 . This position can be monitored by means of an automated or mechanical check in the course of mass production. A further visual characteristic for ascertaining the correct assembly of the plug connector  10  proposed according to the invention resides in the fact that the lands  86  are injected in a different color, such as black, while the retaining clip  22  itself is made in a color that contrasts with them. Both the plug body  12  and the retaining clip  22  received displaceably on it are preferably manufactured in the course of the plastic injection-molding process. 
       FIG. 10  shows a perspective view of the retaining clip. 
     From the view in  FIG. 10 , it can be seen that the retaining clip  22  has the two detent hooks  26  below the end face  24 . The support faces  36  of the retaining clip  22  are located on the outsides of the respective detent hooks. The insides of the detent hooks  26 , embodied facing one another and with the spread  64  relative to one another, are provided with the guide rail  96 . The guide rail  96  can be embodied for instance as a semi-symmetrically or rectangularly or triangularly configured protuberance on the insides of the detent hooks  26 . The guide rails  96  on the inside of the detent hooks  26  that face one another move in counterpart elements embodied as recesses  98 , embodied in complementary fashion to the profiling of the guide rail  96 , on the outside of the plug body  12 , as shown in conjunction with  FIGS. 2 ,  2 A and  7 . By the motion of the retaining clip  22  along the recesses  98 —the guide rails  96  are guided on the inside of the detent hooks  26  during assembly and in the closing operation of the retaining clip  22 , to prevent tilting of the retaining clip  22  during its motion relative to the plug body  12 . It is understood that it is also possible to mount the guide rails  96  on the outside of the plug body  12 , instead of on the inside of the detent hooks  26 , to embody the recesses  98  on the inside of the detent hooks  26  instead of on the outside of the plug body  12 . The grooves  48  for securing the retaining clip  22  in its closing position extend above the guide rails  96 , rotated by 90° to the orientation of the guide rails. 
     From the view in  FIG. 10 , it is also seen that the essentially tonguelike positioning aids  28  are disposed on the ends of the detent hooks  26 , or in other words in the vicinity of the profiled end faces  54  on both detent hooks  26 . These positioning aids are embodied offset from one another, or in other words on different face ends of the detent hooks  26 , but they can also be embodied on facing ends of the detent hooks  26 . 
     The foregoing relates to the preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.