Patent Publication Number: US-2022239044-A1

Title: Plug connector and plug connector assembly

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit to German Patent Application No. DE 20 2021 100 405.3, filed on Jan. 28, 2021, which is hereby incorporated by reference herein. 
     FIELD 
     The present invention relates to a plug connector for transmitting high-frequency or radio-frequency signals, in particular in a vehicle, and to a plug connector assembly. 
     BACKGROUND 
     In a vehicle, various technical components communicate with each other by exchanging data. The data exchange preferably takes place in the form of high-frequency signals passed through suitable cables, such as coaxial cables or micro-coaxial cables. Often, plug connectors are used at interfaces between cables and/or technical components. To facilitate handling in automotive applications, plug connectors are generally standardized; i.e., certain dimensions and sizes of a plug connector are predetermined and must be observed. The requirements are essentially directed to the durability and releasability of the plug connector and to reliable data transmission. However, the standardized dimensions can lead to difficulties during the assembly of connector components, for example when parts are not always fully visible or when excessive play occurs between parts during assembly. 
     German Publication DE 10 2016 002 408 A1 relates to a coaxial plug-and-socket connection and a connection system including this plug-and-socket connection. In addition to a first contact junction between a first coaxial connector and a matching second coaxial connector, a second contact junction is implemented in the plug-and-socket connection in the outer conductor portion thereof. To this end, an elastic contact component is provided between the first coaxial connector and the second coaxial connector at a distance from the first contact junction, in particular at a distance from the first latching means. The elastic contact component preferably takes the form of a toroidally wound ring. The toroidally wound wire of the ring is elastic both radially and axially and bridges different distances between a coaxial socket and a coaxial plug, which can occur depending on a respective radial offset between the coaxial plug and the coaxial socket. In the case of a radial offset, the axis of the connecting element and the axis of a coaxial socket form a certain angle other than zero. 
     However, due to the elasticity of the contact component, the occurrence of a radial offset (i.e., tilting) cannot be ruled out, neither during insertion nor during arrangement of the two connectors within each other. This may lead to further inaccuracies during assembly. Furthermore, the contact component must be disposed as a separate part on a connector, which increases complexity. Finally, the contact component must be configured and mounted such that it is able to withstand the high mechanical dynamics occurring in a vehicle at least over a predetermined lifetime, which is associated with additional effort. 
     SUMMARY 
     In an embodiment, the present invention provides a plug connector for transmitting high-frequency signals that includes a cable, a contact and a connecting element. The cable has at least one free end. The contact is mounted on the at least one free end of the cable, and has a free contact end on a side facing away from the cable. The connecting element is disposed between the contact and the cable, and, in an assembled state, is fixedly connected to the contact and to the cable. The connecting element has at least a first portion with a first outer diameter on a side facing the contact and a second portion with a second outer diameter on a side facing the cable, the second outer diameter being larger than the first outer diameter. The first portion includes at least a third portion that has, at least in some regions of the third portion, an outer diameter corresponding to the second outer diameter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Subject matter of the present disclosure will be described in even greater detail below based on the exemplary figures. All features described and/or illustrated herein can be used alone or combined in different combinations. The features and advantages of various embodiments will become apparent by reading the following detailed description with reference to the attached drawings, which illustrate the following: 
         FIG. 1  is a side view of an embodiment of a plug connector; 
         FIG. 2  is a side view of an embodiment of a plug connector assembly with a plug connector having a connecting element without embossed formations; 
         FIG. 3  is a view of the plug connector assembly of  FIG. 2  with a plug connector having a connecting element with embossed formations, shown during assembly; 
         FIG. 4  is a view showing the plug connector assembly of  FIG. 3  in the assembled state; 
         FIG. 5  is a perspective view of the plug connector assembly of  FIG. 4 ; 
         FIGS. 6 a  and 6 b    are a side view ( FIG. 6 a   ) and a perspective view ( FIG. 6 b   ) of a star-type compression tool for producing embossed formations on the connecting element; and 
         FIG. 7  is a cross-sectional view showing a plug connector in the star-type compression tool during or after the compression operation. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention provide a plug connector for transmitting high-frequency signals as well as a plug connector assembly which are simple and rugged in construction, meet the required standards, and enable quick and reliable assembly. 
     In particular, a plug connector that is simple and rugged in construction, meets the required standards, and enables quick and reliable assembly is achieved by a plug connector for transmitting high-frequency signals according to an embodiment of the present invention. The plug connector has a cable having at least one free end, as well as a contact mounted on the free cable end and having a free contact end on a side facing away from the cable, and further has a connecting element which is disposed between the contact and the cable and which, in the assembled state, is fixedly connected to the contact and to the cable. The connecting element has at least a first portion with a first outer diameter on a side facing the contact and at least a second portion with a second outer diameter on a side facing the cable, the second outer diameter being larger than the first outer diameter. Finally, the first portion includes at least a third portion, the connecting element at least in some regions of the third portion having an outer diameter corresponding to the second outer diameter. 
     The plug connector allows the cable to be connected to a terminal that is complementary to the contact. The cable is preferably a coaxial cable or a micro-coaxial cable, and the terminal is preferably a corresponding coaxial connector. Via the plug connector, high-frequency signals can be transmitted in a vehicle. The plug connector may also be used for other types of cables. The line groups mounted in the plug connector are preferably of the common low loss (LL) and radio guide (RG) types, which differ in their diameter or dimensioning. Due to these differences, a variation in diameter may occur along the connecting element during the assembly of a plug connector, especially during the crimping of the connecting element. 
     The dimensioning of a housing for receiving at least one plug connector; i.e., also the dimensioning of at least one plug connector receptacle, is essentially strictly defined. In accordance with the defined dimensioning, the at least one plug connector receptacle has a uniform cylindrical shape. In the uniform cylindrical shape, the above-described variation in diameter of the connecting element leads to a variation in the joining situation in the plug connector receptacle, and thus to play between the peripheral wall of the plug connector receptacle and at least a first portion of the connecting element, which first portion has a smaller diameter. Such play may result in tilting of the plug connector and difficulties during assembly. In particular, when the plug connector is inserted at an angle, it is likely to collide with a push-through guard in the housing. 
     An embodiment of the present invention is intended to compensate for variations in diameter so as to ensure a uniform joining situation without impairing the mechanical and electrical properties of the plug connector. In a certain area, the diameter is, at least in some regions, increased by an embossed formation, preferably a bump or projection. This makes it possible to reduce or prevent the occurrence of (wobbling) play during fitting of the plug connector into the housing. For this purpose, the first portion of the connecting element, which has a smaller outer diameter than a second portion, includes a third portion which has an outer diameter corresponding to the second outer diameter at least in some regions in the circumferential direction of the connecting element. 
     During insertion of the plug connector into the housing, the plug connector is inserted with the free end of the contact forward into the housing. Since the first portion, and thus also the third portion, is disposed on a side facing the free contact end, the third portion enters the housing before the second portion. Furthermore, the plug connector can be inserted unhindered into the housing up to the third portion, preferably up to the beginning of the third portion, as viewed from the free contact end. The mentioned push-through guard is further away. With the insertion of the third portion, the plug connector can be accurately aligned with the housing or the plug connector receptacle in the housing. In this process, the third portion is visible from the outside and disappears from the field of view as it is inserted into the housing. The visibility simplifies the alignment and thus the assembly process. 
     Preferably, an outer diameter of the contact is smaller than an outer diameter of the cable. The dimensioning of the contact and of the cable is predetermined. To allow for a space-saving arrangement and connection, the contact typically has a smaller diameter than the cable. 
     In the assembled state, the connecting element preferably directly embraces the contact and the cable in its first and second portions, respectively. The direct and snug joining ensures a space-saving and reliable connection. The direct joining preferably includes crimping of the connecting element so that the contact and the cable are frictionally connected together. Because the contact and the cable have different outer diameters, different outer diameters are formed along the connecting element as it is directly embraced. 
     Preferably, the connecting element includes a compression sleeve such as a crimp sleeve or a compression tube. A compression or crimp sleeve is a standard component and is simple and cost-effective to use. The compression or crimp sleeve is preferably formed from a metal. The compression or crimp sleeve can be readily connected to the contact and the cable, in particular using a compression tool. In particular, the third portion may be formed during the compression operation. Preferably, the compressing is performed using a star-type compression tool since this tool allows for an even distribution of compression force or pressure. 
     Preferably, the third portion has a plurality of embossed formations formed in spaced-apart relationship on the periphery of the connecting element. The embossed formations preferably include projections. The number of embossed formations around the circumference may be defined by the required pull-off strength. The embossed formations can readily be produced or formed into the connecting element during a compression operation. In particular, no additional steps or fastening means are required for the embossed formations. The plurality of embossed formations are arranged such that there is at least one section of the third portion that has an outer diameter corresponding to the second outer diameter. Preferably, the embossed formations are arranged in diametrically opposite pairs on the periphery of the connecting element. 
     Preferably, the embossed formations are integral with the connecting element. The connecting element preferably includes a dimensionally stable material, in particular metal. Because the embossed formations are formed integrally from the connecting element, the embossed formations are also composed of the dimensionally stable material of the connecting element. Thus, the embossed formations cannot be compressed or bent during assembly without a separate compression tool. Because of this, the plug connector can at all times be reliably inserted into the housing without unwanted play. 
     Preferably, guide elements are disposed at the embossed formations in the transitions between the first portion and the third portion. Due to their shape, the guide elements facilitate the insertion of the plug connector into the receiving opening of the housing. This simplifies assembly. 
     Preferably, a distance between the free contact end and the third portion is smaller than a distance between the free contact end and the second portion. This means that the third portion is located closer to the free contact end. The plug connector is inserted with its free contact end first into the housing. Consequently, the third portion reaches or enters the housing before the second portion. The plug connector is aligned with the housing as early as when the third portion is inserted. 
     A plug connector assembly that is simple and rugged in construction, meets the required standards, and enables quick and reliable assembly is also achieved in particular by a plug connector assembly for at least one plug connector for transmitting high-frequency signals according to an embodiment of the present invention. The plug connector assembly has at least one plug connector and a housing with at least one plug connector receptacle for disposing the at least one plug connector in the housing. The at least one plug connector receptacle has an inner diameter corresponding to the second outer diameter of the connecting element and a length corresponding to at least a distance between the free contact end and the third portion. 
     The plug connector assembly preferably has a plurality of plug connector receptacles. This allows a plurality of plug connectors to be connected simultaneously to complementary terminals. The housing protects the connectors from the outside environment. In addition, the housing provides latching features for a reliable connection between a plug connector and a complementary terminal. Preferably, in the assembled state, the respective plug connector and the housing are also in engagement with one another, in particular via latching means. The housing and a plug connector receptacle respectively have a predefined fixed length in the longitudinal direction of the cable. In particular, the length is selected such that a plug connector is securely disposed in the housing. The length of the plug connector receptacle may in particular be a multiple of a diameter of a receiving opening, so that an end of the plug connector receptacle opposite the receiving opening is only visible when viewed in a direction along the plug connector receptacle. 
     Preferably, the plug connector assembly further has a push-through opening with a push-through guard, the push-through opening having a diameter corresponding to the outer diameter of the contact. The push-through opening is surrounded by the push-through guard. The push-through guard forms in particular a wall. In order for a plug connector to reach its final position within the housing, the contact of the plug connector must be pushed through the push-through opening. Since the diameter of the push-through opening corresponds exactly to the outer diameter of the contact, the plug connector must be accurately aligned within the housing and, in particular, along receptacle axis A in order to move the plug connector through the push-through opening. Accurate alignment is important inter alia for reliable connection to a terminal connectable to the contact. 
     In addition, further advantages and features of embodiments of the present invention will be apparent from the following description of preferred embodiments. The features described therein and hereinabove may be implemented alone or in combination, unless they contradict each other. The following description of the preferred embodiments is made with reference to the accompanying drawings. 
       FIG. 1  shows an embodiment of a plug connector  1  in a side view along a central axis M. Plug connector  1  has a contact  10 , a cable  20 , and a connecting element  30 . Connecting element  30  is configured as a hollow cylinder and surrounds an end of contact  10  and an end of cable  20 . Preferably, contact  10  and cable  20  abut against each other within connecting element  30 . Due to the abutment between contact  10  and cable  20 , electrical signals, in particular high-frequency signals, can be transmitted in both directions. Contact  10  preferably has an inner conductor  13  and an outer conductor  15  annularly surrounding inner conductor  13  (see  FIG. 5 ). At contact  10 , the high-frequency signals are preferably transmitted via inner conductor  13 . Outer conductor  15  preferably serves as a shield for inner conductor  13 . In the assembled state, connecting element  30  is fixedly, in particular permanently, connected to contact  10  and cable  20 , holding contact  10  and cable  20  together. 
     Contact  10 , also referred to as a cable output, is connectable to a terminal complementary to contact  10 , so that signals can be exchanged between cable  20  and the complementary terminal via plug connector  1 . The dimensions of contact  10  for connection to the complementary terminal are predetermined. In particular, contact  10  has a predetermined length. Contact  10  further has an outer diameter D 11 . In the embodiment shown in  FIG. 1 , contact  10  further has a sleeve  16  having a front edge  17 . Front edge  17  faces toward a free end  12  of contact  10 . Free end  12  of contact  10  has an edge  14 . Edge  14  preferably forms part of outer conductor  15  of contact  10 . Therefore, edge  14  is in particular annular. In a preferred embodiment, edge  14  has a shape that tapers toward free end  12 . The tapered shape facilitates the connection of a terminal that is complementary and connectable to contact  10  and/or the insertion of contact  10  through a push-through opening  58  in a housing  50  of a plug connector assembly  40  (see  FIG. 3 ). 
     Cable  20  is preferably a coaxial cable or micro-coaxial cable for transmission of high-frequency signals. In other embodiments, other types of cables may also be used. Cable  20  has an outer diameter D 22 . Outer diameter D 22  is preferably larger than outer diameter D 11  of contact  10 . 
     Connecting element  30  is preferably a crimp sleeve or a compression tube. Connecting element  30  is preferably compressible so that it permanently surrounds an inserted contact and/or a cable as it is compressed or crimped. In the embodiment shown in  FIG. 1 , connecting element  30  has at least a first and a second portion I, II. 
     First portion I is located on a side facing contact  10 . First portion I surrounds an end of contact  10  directly, snugly, and firmly. Second portion II is located on a side facing cable  20 . Second portion II surrounds an end of cable  20  directly, snugly, and firmly. Since outer diameter D 11  of contact  10  is preferably smaller than outer diameter D 22  of cable  20 , the first outer diameter D 1  of connecting element  30  in first portion I is smaller than the second outer diameter D 2  of connecting element  30  in second portion II. In particular, second outer diameter D 2  of connecting element  30  corresponds to a maximum outer diameter in the assembled state; i.e., after compression. The maximum outer diameter is preferably in the range of 2-5 mm, more preferably in the range of 2.5-4 mm, even more preferably in the range of 3-3.5 mm. These and all other dimensions can be scaled as desired to other plug connectors. 
     Second portion II is spaced from free end  12  of contact  10  by a minimum distance L 3 . Between first portion I and second portion II, there may be provided a transition section  36  in which the outer diameter of connecting element  30  increases from first outer diameter D 1  to second outer diameter D 2 , proceeding from the side facing contact  10 . 
     First portion I has a third portion III, the third portion III being preferably shorter than first portion I and preferably spaced apart from second portion II and from transition section  36 . Third portion III preferably has a length in the range of 0.3-1 mm, more preferably in the range of 0.4-0.8 mm, even more preferably in the range of 0.5-0.6 mm. Third portion III is spaced from free end  12  of contact  10  by a minimum distance L 1 . Distance L 1  is preferably smaller than distance L 3 . Distance L 1  is preferably in the range of 12-18 mm, more preferably in the range of 13-16 mm, even more preferably in the range of 14-15 mm. 
     Third portion III is preferably an annular or cylindrical portion along connecting element  30 . Third portion III has in particular at least one embossed formation  32  disposed therein. In the case of a single embossed formation  32 , embossed formation  32  preferably extends over more than half the circumference. In an alternate embodiment, embossed formation  32  may also extend over the entire circumference. Preferably, third portion III has a plurality of embossed formations  32 . A plurality means two or more embossed formations. The plurality of embossed formations  32  are preferably spaced apart along the circumference of connecting element  30 , so that in at least a sub-region of third portion III, the outer diameter of connecting element  30  corresponds to second outer diameter D 2  of connecting element  30 . For this purpose, in particular, at least two embossed formations  32  are arranged on diametrically opposite sides of the periphery of connecting element  30 . 
     Preferably, guide elements  34  are disposed at the transitions of the at least one embossed formation  32  between the first and the third portions I, III. In the embodiment shown, guide elements  34  have an inclined plane and are disposed on both sides of each embossed formation  32 . In other embodiments, guide elements  34  may have other shapes such as curved planes, stepped shapes, rounded edges, etc. Furthermore, in other embodiments, guide elements  34  may be disposed only on the side facing contact  10 . Guide elements  34  serve to facilitate the insertion of plug connector  1  with connecting element  30  into a plug connector receptacle  52  of a housing  50  (see  FIG. 2 - FIG. 5 ). The region or regions along central axis M of plug connector  1  where guide elements  34  are disposed may form a separate portion because there the outer diameter is larger than first outer diameter D 1  and smaller than second outer diameter D 2  of connecting element  30 . Guide elements  34  may be formed together with the embossed formations  32 , in particular during a compression operation. Preferably, guide elements  34  are integral with connecting element  30 . 
       FIG. 2  through  FIG. 5  show a plug connector assembly  40  having a housing  50  and a plug connector  1  being inserted into housing  50 . In the embodiment shown, housing  50  has a total of four plug connector receptacles  52 , in each of which may be disposed a plug connector  1 . Each plug connector receptacle  52  may be identical in design, and a plurality of plug connector receptacles  52  may also be arranged differently than shown in  FIG. 2  through  FIG. 5 . For example, they may all be arranged side by side in a housing  50 . 
     In order for a plug connector  1  to be received in one of plug connector receptacles  52 , central axis M of plug connector  1  is aligned with the corresponding receptacle axis A. Then, plug connector  1  is inserted with the free end  12  of its contact  10  forward through receiving opening  54  into plug connector receptacle  52 . Diameter D 4  of plug connector receptacle  52  and receiving opening  54  preferably corresponds to the maximum outer diameter of plug connector  1 ; i.e., to second outer diameter D 2  in second portion II of connecting element  30 . Thus, plug connector  1  can be completely inserted into housing  50  and plug connector receptacle  52  and is finally seated. 
     A push-through opening  58  is disposed opposite each receiving opening  54 . Receptacle axis A extends centrally through plug connector receptacle  52  and push-through opening  58 . Each push-through opening  58  is surrounded by a push-through guard  56 , which determines inner diameter D 3  of push-through opening  58 . Push-through guard  56  is in particular a wall. Inner diameter D 3  of push-through opening  58  corresponds to outer diameter D 11  of contact  10 . Plug connector  1  can be pushed through push-through opening  58  up to a sleeve edge  17  of sleeve  16 . When sleeve edge  17  abuts against push-through guard  56 , plug connector  1  has reached its optimal end position within housing  50 . Connector  1  is fixed in its end position by locking means. 
     Furthermore,  FIG. 2  shows a plug connector  1  which has no embossed formations  32  on connecting element  30 . Outer diameter D 11  of contact  10  and first outer diameter D 1  in the first portion of connecting element  30  are smaller than inner diameter D 4  of receiving opening  54  and plug connector receptacle  52 . Due to the difference in diameter, a clearance is formed between plug connector  1  and the peripheral walls of plug connector receptacle  52 . This clearance provides for some play SP during insertion of plug connector  1  into plug connector receptacle  52 , whereby plug connector  1  can not only be moved along plug connector receptacle  52 , but can also be moved, in particular tilted, transversely to plug connector receptacle  52 . Due to the tilting, central axis M of plug connector  1  and receptacle axis A of plug connector receptacle  52  no longer coincide. 
     Push-through guard  56  is generally disposed in housing  50  in such a way that it is only visible when viewing in a direction along receptacle axis A. However, when inserting plug connector  1  into housing  50 , assembly personnel cannot move plug connector  1  along receptacle axis A and at the same time look along this axis A. When plug connector  1  and central axis M are tilted by an angle α with respect to receptacle axis A, free end  12  of contact  10  abuts against push-through guard  56  in a sub-region of edge  14  of free end  12 . This means that when plug connector  1  is in a tilted condition, it cannot be inserted further into plug connector receptacle  52  and housing  50 . Plug connector  1  does not reach its optimal end position and is not locked in place. The assembly personnel can only tilt plug connector  1  back and forth to change the angle of inclination a in an attempt to push free end  12  of contact  10  through push-through opening  58 . This manner of assembly is time-consuming and frustrating. In addition, components may be damaged if haptic feedback upon abutment is the only way of determining whether plug connector  1  is correctly aligned in plug connector receptacle  52 . 
       FIG. 3  shows a plug connector  1  having a connecting element  30  with embossed formations  32 . As a result of the embossed formations  32 , the outer diameter of plug connector  1  at least in some regions in third portion III of connecting element  30  corresponds to second outer diameter D 2  in second portion II. Distance L 1  between free end  12  of contact  10  and third portion III corresponds to distance L 2  between push-through opening  58  or push-through guard  56  and receiving opening  54 . In an alternative embodiment, distance L 1  may also be smaller than distance L 2 . In the case of a distance L 1  smaller than or equal to distance L 2 , third portion III of connecting element  30  reaches receiving opening  54  before or at the same time as free end  12  of contact  10  abuts against push-through guard  54 . In order to push plug connector  1  further into housing  50 , third portion III, which the assembly personnel can see from outside, must be correctly aligned with receiving opening  54 . “Correctly aligned” means that central axis M coincides with receptacle axis A. By bringing the two axes A, M into coincidence, free end  12  of contact  10  is also aligned centrally with respect to push-through opening  58 . By moving plug connector  1  along axes A, M, it can be brought into its end position in housing  50 . Because third portion III is visible from the outside during insertion into the receiving opening  54 , the assembly personnel can visually recognize proper alignment and readjust it if necessary. There is no need to tilt plug connector  1  back and forth in housing  50 . 
       FIG. 4  and  FIG. 5  show plug connector  1  in its end position in housing  50 . Contact  10  is inserted through push-through opening  58  up to the point where sleeve edge  17  of sleeve  16  abuts against push-through guard  56 . Contact  10  protrudes out of push-through opening  58  to the maximum possible extent on a side opposite the plug connector receptacle  52  so that contact  10  can be connected to a complementary terminal. Furthermore, plug connector  1 , together with connecting element  30 , is inserted as far as possible into plug connector receptacle  52  and locked in place therein. This provides protection for plug connector  1  and connecting element  30  in housing  50  and ensures a reliable connection. Due to the embossed formations  32  in third portion III, plug connector  1  has additional points of radial contact with the inner surface of plug connector receptacle  52 , which improves the positioning of plug connector  1  in plug connector receptacle  52 . 
     The dimensions of the components, in particular of housing  50  and contact  10 , are predetermined. In particular, the dimensions are defined by standards and cannot be changed as desired. The creation of a third portion III with an outer diameter that corresponds to the maximum outer diameter of plug connector  1  in the assembled state can be accomplished during or after the mounting of connecting element  30  on contact  10  and/or cable  20 . In particular, as shown in  FIG. 6  and  FIG. 7 , embossed formations  32  can be created using a star-type compression tool  100 . Star-type compression tool  100  is designed to bring a stamped and bent component, such as a crimp sleeve having an abutting edge or a completely closed tube, into a desired shape. Star-type compression tool  100  is made up of a plurality of compression elements  102  arranged circumferentially along the length of connecting element  30 . Compression elements  102  can be synchronously moved radially toward central axis M of plug connector  1 . In an open position, compression elements  102  are spaced from the central axis M and preferably spaced apart from each other. In order to perform compression, the compression elements are moved radially toward central axis M. The synchronous movement of compression elements  102  causes an even compression force or pressure to be applied to connecting element  30 , thereby joining connecting element  30  to contact  10  and to cable  20 . All compression elements  102  have the same regions complementary to the compressed connecting element  30 . Because of this, the same pressure is applied in each region. 
     In addition, at least some of compression elements  102  have at least a portion of a recess  104 . In the final compressed state, recesses  104  form shapes complementary to embossed formations  32  on connecting element  30 . Embossed formations  32  may be created by recesses  104  during compression. In an alternative embodiment, embossed formations  32  were formed on connecting element  30  already prior to compression in star-type compression tool press  100 , and recesses  104  in star-type compression tool press  100  allow the embossed formations  32  to be maintained and an even pressure force to be applied to connecting element  30 . 
     While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above. 
     The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C. 
     LIST OF REFERENCE SYMBOLS 
     
         
           1  plug connector 
           10  contact 
           12  free contact end 
           13  inner conductor 
           14  edge 
           15  outer conductor 
           16  sleeve 
           17  sleeve edge 
           20  cable 
           30  connecting element 
           32  embossed formation 
           34  guide element 
           36  transition section 
           40  plug connector assembly 
           50  housing 
           52  plug connector receptacle 
           54  receiving opening 
           56  push-through guard 
           58  push-through opening 
           100  star-type compression tool 
           102  compression elements 
           104  recess 
         α angle 
         A receptacle axis 
         D 1  first outer diameter 
         D 2  second outer diameter 
         D 11  outer diameter of the contact 
         D 22  outer diameter of the cable 
         D 3 , D 4  diameter 
         I, II, III portions 
         L 1 -L 3  lengths 
         M central axis 
         SP play