Abstract:
The invention relates to a functional element comprising a longitudinal axis, a body part, a hollow pressed part, an annular supporting surface which is arranged on the body part, substantially extended in a perpendicular direction with respect to the longitudinal axis and is radially displaced away from the pressed part and an annular groove which axially extends and is embodied in the body part radially inside the supporting surface. Locking ribs are preferably provided and at least partly cross the annular groove and the free end of the pressed part is provided with an annular cutting edge. The invention functional element is characterized in that an annular bulge is embodied on the pressed part between the annular supporting surface and the free end of the pressed part and an annular cavity is embodied around said pressed part between the bulge and the front free end thereof. An assembly component consisting of the functional element combined with a metal sheet, a method for producing the assembling component and a method for producing the functional element are also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a division of U.S. patent application Ser. No. 10/595,837, filed Sep. 20, 2006, pending, which claims priority from PCT/EP04/12991 filed on Nov. 16, 2004, which claims priority of German Patent Application No. 103 53 642.6, filed Nov. 17, 2003, the disclosures of which is expressly incorporated by reference herein in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a functional element having a longitudinal axis, a body section, a hollow piercing section, a ring-like contact surface at the body part, which extends substantially perpendicular to the longitudinal axis and radially away from the piercing section, and an axially extending ring groove which is provided in the body section radially inside the contact surface, with the functional element being designed for attachment to a component which is of plate-like shape at least in the region of the attachment, in particular to a sheet metal part, wherein the body section has a pressing surface at the side remote from the piercing section and wherein ribs providing security against rotation are preferably provided which cross the ring groove at least in part and wherein the free end of the piercing section is provided with a ring-like cutting edge. Furthermore the present invention relates to a component assembly, to a method for manufacture of a component assembly and also to a method for the manufacture of the functional element. 
       BACKGROUND OF THE INVENTION 
       [0003]    A functional element of the initially named kind is known from EP 0 713 982 25 B1. 
         [0004]    Although the known element can also be self-piercingly introduced into a sheet metal part, the element is not ideally designed for this purpose. 
         [0005]    A further functional element which is at least similar to the element of EP 0 713 982 B1 at a first glance is known from EP 0 678 679 B1, but does not have a piercing section and is not suitable for the self-piercing introduction into a sheet metal part. 
       SUMMARY OF THE INVENTION 
       [0006]    The object underlying the present invention is to provide a functional element of the initially named kind which is particularly suited for the self-piercing introduction into a sheet metal part, which can be manufactured at reasonable cost and which can also be used with a broad spectrum of sheet metal thicknesses, without the functional element having to have a special design for each sheet metal thickness. 
         [0007]    In order to satisfy this object a functional element of the initially named kind is provided which is characterized in that a ring-like bead is provided at the piercing section between the ring-like contact surface and the free end of the piercing section and in that a ring recess is preferably provided around the piercing section between the bead and the free end face of the piercing section. 
         [0008]    The diameter of the piercing section at the ring-like cutting edge can be larger than the maximum transverse dimension of the ring-like bead, but can also be of the same size or smaller than this maximum transverse dimension. 
         [0000]    In all these variants, with a suitable design of the die button that is used, it can be ensured that, on the attachment of the functional element to a sheet metal part, a clean piercing slug arises out of the sheet metal part, through the cooperation between the ring-like cutting edge of the piercing section and the central bore of the die button used to manufacture the component assembly consisting of the functional element and the sheet metal part. On the other hand, in particular when using thinner sheet metal parts, it can, however, also be ensured that the sheet metal material can be guided past the ring-like bead without damaging the latter. 
         [0009]    When using thicker sheet metal parts, the ring projection of the die button moves, depending on the specific dimensions of the sheet metal part and the functional element, less far in the longitudinal direction of the piercing section, past the ring-like cutting edge, so that the end face boundary of the bore of the die button does not reach the ring-like bead. The sheet metal part is then pressed into the ring-like recess between the ring-like bead and the ring-like cutting edge, and indeed without the sheet metal material being unnecessarily thinned between the apex of the ring-like bead and the end face boundary of the die button when unfavorable sheet metal thicknesses are present. In this manner the sheet metal material engages around the ring-like bead and contributes to the press-out and pull-out resistance. 
         [0010]    It is particularly favorable when the ring groove runs out into the ring-like contact surface via an at least substantially conical surface. 
         [0011]    On attachment of the functional element to the sheet metal part, sheet metal material is pressed by the die button into the ring groove and a smooth transition is present from the sheet metal material in the groove to the sheet metal material at the ring-like contact surface, whereby the sheet metal part is not unnecessarily thinned or injured in this region. 
         [0012]    The ring-like bead preferably has an at least substantially triangular shape in an axial section plane. This is a stable shape for the ring bead and also leads to an excellent engagement between the ring bead and the sheet metal material. 
         [0013]    The ring recess preferably extends radially inside the ring-like bead and is likewise preferably bounded by the ring-like bead at the side remote from the free end face of the piercing section. This design leads to a compact and on the whole short design of the piercing section and permits a sensible design of the functional element so that this can, on the one hand, be used with different sheet metal thicknesses. 
         [0014]    The functional element can be realized as a fastener element, for example as a hollow fastener element, which has a fastener section provided to receive a bolt. 
         [0015]    In the event that the functional element is realized as a fastener element, it can be favorable to form in the body part with a flange section with the ring-like contact surface and the axially extending ring groove being provided at or in the flange section at its side facing the flange section. The side of the flange section remote from the piercing section is preferably formed as a ring-like contact surface, with a plunger for the attachment of the functional element to a sheet metal part preferably pressing against the ring-like contact surface. This has the advantage that any thread which may be provided in the functional element is not deformed under the action of the force exerted by the plunger onto the flange section. 
         [0016]    The fastener section can have one of the designs wherein said fastener section can be: 
         [0017]    a) located at the side of the flange section remote from the piercing section; 
         [0018]    b) located at the side of the flange section remote from the piercing section and extending at least partly into the flange section; 
         [0019]    c) located at the side of the flange section remote from the piercing section and extends through the total axial thickness of the flange section; 
         [0020]    d) located at the side of the flange section remote from the piercing section and extending through the total axial thickness of the flange section and also through a Palt of the axial length of the piercing section; 
         [0021]    e) located at the side of the flange section remote from the piercing section and extending through the total axial thickness of the flange section and also through the total axial length of the piercing section; 
         [0022]    f) located at the side of the flange section adjacent the piercing section and extending through a part of the axial thickness of the flange section and also through a part of the total axial length of the piercing section; 
         [0023]    g) located at the side of the flange section remote from the piercing section and extending through a part of the axial thickness of the flange section and also through the total axial length of the piercing section; 
         [0024]    h) located at the side of the flange section adjacent the piercing section and extending only through the total axial length of the piercing section; or 
         [0025]    i) located at the side of the flange section adjacent the piercing section and extending only through a part of the total axial length of the piercing section. 
         [0026]    When the functional element is realized as a fastener element, it is necessary to take measures to retain the functional element in the sheet metal part in a manner secured against rotation. In order to achieve this, features providing security against rotation are preferably to be provided, for example in the ring groove. In accordance with a particularly preferred embodiment, the base surface of the ring groove is provided on at least a part of its radial extent with noses providing security against rotation and/or grooves providing security against rotation. It is most favorable when ribs providing security against rotation are provided which bridge the peripherally extending recess. 
         [0027]    In accordance with a particularly preferred embodiment of the ribs providing security against rotation, these extend in raised manner in the radial direction within the ring groove and furthermore in raised manner in the axial direction within the ring groove up to the bead. This signifies that the ribs providing security against rotation have an at least substantially rectangular shape with two limbs. 
         [0028]    In this connection, the radially extending sections of the ribs providing security against rotation do not project in the radial direction beyond the apex point of the bead and they can with advantage also be set back slightly radially with respect to the apex point. 
         [0029]    It is particularly favorable when the ring-like bead has the shape of at least one turn of a thread. As a result of the pitch of the thread it can be ensured that a part of the bead is always in engagement with the sheet metal part irrespective of the respective thickness of the sheet metal, whereby, on the one hand, the resistance to rotation and, on the other hand, also the resistance to pull-out or press-out can be increased. 
         [0030]    It is particularly favorable when the bead has the shape of at least two sections of a turn of a thread, since the engagement of the sheet metal material with the bead takes place independently of the sheet metal thickness at angularly spaced regions of the sections. 
         [0031]    An arrangement is particularly preferred in which the bead has the shape of sections of a turn of a left hand thread and of a turn of a right hand thread which are alternately arranged around the longitudinal axis. This not only increases the resistance to rotation in both directions, but also ensures that the thread or the thread sections lie in regions which can be considered with a large number of possible sheet metal thicknesses. It is in particular favorable when the turn sections are connected to one another and preferably form a closed ring. In this example four turn sections could, for example, be provided. 
         [0032]    The functional element can not only be realized as a fastener element. Instead of this, the functional element could for example be realized as a hollow sleeve which is designed to receive a rotatable shaft or a pin-like clip. Furthermore, the functional element could be designed such that a pin projects away from the body part, and indeed preferably at the side of the body part which is remote from the piercing section. The pin could also be realized as a clip mount whereby, for example, a carpet or the like can be clipped onto the pin. 
         [0033]    Particularly preferred embodiments of the functional element of the invention and also of the component assembly, the method for manufacturing the component assembly and the method for manufacturing the functional element can be seen from the patent claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    The invention will be explained in the following in more detail with reference to embodiments and to the drawing in which are shown: 
           [0035]      FIG. 1  a side view of a functional element in accordance with the invention, and indeed in an axial section onto the left hand side of the central longitudinal axis and from the outside onto the right hand side of the central longitudinal axis, 
           [0036]      FIG. 1A  an enlarged representation of the element of  FIG. 1  in an axial section and in the region of a ring groove in which the ribs providing security against rotation are arranged, 
           [0037]      FIG. 2  a schematic representation of the attachment of the functional element of  FIG. 1  to a sheet metal part and indeed in a first stage at the left hand side of the central longitudinal axis and in a second stage at the right hand side of the central longitudinal axis, 
           [0038]      FIG. 3  a representation after the completion of the attachment method of  FIG. 2 , 
           [0039]      FIG. 4  a schematic illustration of a functional element in accordance with the invention after the attachment to a sheet metal part with a special design of the sheet metal part, 
           [0040]      FIG. 5  a schematic representation of a further embodiment of a functional element in accordance with the invention similar to  FIG. 1 , 
           [0041]      FIGS. 6 ,  7 ,  8 ,  9  a series of drawings to explain the manufacture of a functional element in accordance with the invention by cold heading and 
           [0042]      FIG. 10  a side view of the finished functional element in accordance with  FIG. 9 , with  FIG. 10  simultaneously showing a further embodiment of a functional element in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0043]      FIG. 1  shows a functional element  10  in accordance with the invention having a longitudinal axis  14 , a body part  16 , a hollow piercing section  18 , a ring-like contact surface  20  at the body part which lies in a plane arranged substantially perpendicular to the longitudinal axis  14  and extends radially away from the piercing section  18  and an axially extending ring groove  21  which is provided in the body section radially inside of the contact surface. The functional element is designed for attachment to a component  22  having a plate-like shape at least in the region of the attachment ( FIG. 2 ), in particular to a sheet metal part. Furthermore, the body part  16  has a ring-like pressing surface  24  at the side remote from the piercing section  18 . 
         [0044]    On the attachment of the functional element to a sheet metal part, pressure is exerted against the pressing surface  24  by means of a plunger as will later be explained in more detail with reference to  FIGS. 2 to 4 . 
         [0045]    Ribs  26  providing security against rotation, which can best be seen from the detailed drawing of  FIG. 1A , cross the ring groove  22  in this example. Such ribs providing security against rotation are in particular required if the functional element is a fastener element, as shown here in the form of a nut element with an internal thread  12 . The free end  28  of the piercing section  18  is provided with a ring-like cutting edge  20 . 
         [0046]    The design of the piercing section of the fastener element  10  is of particular importance in accordance with the invention. One sees from  FIG. 1  that a ring-like bead  32 , which in this example is formed as a closed ring bead, is provided at the piercing section between the ring-like contact surface  20  and the free end  28  of the piercing section  18 . Furthermore, a ring recess  34  around the piercing section is located between the bead and the free end face of the piercing section. 
         [0047]    In this example, the ring-like cutting edge ( 30 ) lies radially further outwardly than the apex of the bead. I.e. the diameter of the cutting edge is dimensioned such that it is larger than the maximum transverse dimension of the bead  32 . In the case of the ring-like bead  32  of the embodiment of  FIG. 1  the bead is of circular shape at the tip whereby the maximum transverse dimension corresponds to the diameter of the ring bead at the tip. When the ring bead has, in accordance with a preferred embodiment, the shape of a thread turn, i.e. the turn of a thread or the form of thread turns or of sections of a thread turn, the apex points of the bead always lie on the surface of an imaginary envelope cylinder ( 106  in  FIG. 5 ), the diameter of which then represents the maximum transverse dimension of the thread. 
         [0048]    It is, however, not absolutely essential that the diameter of the ring-like cutting edge  20  is larger than the maximum transverse dimension of the bead  32 . Instead of this, the diameter of the ring-like cutting edge  30  could correspond to the maximum transverse dimension of the bead  32  or be smaller than it. 
         [0049]    As is evident from  FIG. 1  and above all from  FIG. 1A , the ring groove  21  runs out via an at least substantially conical surface  36  into the ring-like contact surface  20 . At the radially inner side, the axially extending ring groove  21  forms, together with the bead  32 , a radial ring groove  38  which is rounded in cross-section, in particular in the base region of the ring groove which is located in the body section  16 . 
         [0050]    As can likewise best be seen from  FIG. 1A  the ring-like bead  32  has an at least substantially triangular shape in an axial section plane and in this example both side flanks  33 ,  35  of the bead form an angle of at least substantially 30° with a plane perpendicular to the central longitudinal axis of the element, as is shown for the lower flank  33 . 
         [0051]    The ring recess  34  extends radially within the ring-like bead, i.e. radially within the envelope cylinder which defines the locus of the apex points of the bead, and the ring recess is preferably bounded at the side remote from the free end face of the piercing section, preferably by the ring-like bead, i.e. it merges gently into this ring-like bead without an intermediate region. 
         [0052]    The ring recess  34  itself is of at least substantially U-shape seen in an axial section plane and preferably has at least substantially the shape of a semicircle. 
         [0053]    In this example the body section  16  is provided with a flange section  40 , with the ring-like contact surface  20  and the axially extending groove  21  being provided at or in the flange section  40  at its side facing the piercing section, whereas the side of the flange section  40  remote from the piercing section fowls the ring-like pressing surface  24 . This shape of the functional element, which can for example be favorable for a fastener element, is not absolutely essentially; instead of this, the jacket surface of the body section  16  could extend in accordance with the broken line  42  in  FIG. 1 , with the ring-like pressing surface then being located at the upper end of the functional element in  FIG. 1  as indicated at  24 ′. 
         [0054]    As stated, the functional element of  FIG. 1  is formed as a nut element with a thread  12 , with the thread  12  running out into a conical thread run-out recess at the upper end face  44  of the functional element. 
         [0055]    One sees in  FIG. 1  that the fastener section  13  of the fastener element defined by the thread  12  is located exclusively in the region of the body part  16  and merges at its lower end in  FIG. 1  via a conical or rounded surface  46  into a cylindrical hollow space  50  with a diameter which is somewhat larger than the outer diameter of the thread cylinder  12 . The cylinder  50  in turn merges via an either conical or slightly rounded ring surface  52  into the lower ring-like end face  54  of the piercing section  18  at the free end face  28  of the piercing section. The ring-like end face  54  lies in this example in a plane which stands perpendicular to the central longitudinal axis  14  of the element. This is, however, not absolutely essential. The ring-like end face  54  could also be formed as a conical surface with an included cone angle smaller than 180°, for example in the range from 180° to 150° or less. 
         [0056]    This form of the element  10  or of the hollow space  48  is, on the one hand, technically favorable in the manufacture of the functional element and facilitates, on the other hand, the introduction of a screw into the thread from below, since the ring-like surface  52 , the cylindrical surface  50  and the rounded or conical surface  46  serve for progressive centring of the screw when it is introduced into the thread  12 . 
         [0057]    It is likewise evident from  FIG. 1  that the ring-like cutting edge  30  at the lower side is formed by the planar ring-like end face  54  of the functional element, i.e. by a surface which stands perpendicular to the longitudinal axis of the functional element and is surrounded at the radially outer side by a cylindrical surface  56 , i.e. the ring-like cutting edge represents the intersection of the cylindrical surface  56  and the end face  54 . 
         [0058]    Although, in this example, the fastener section defined by the thread  12  is fully located in the body part  16  of the functional element, this is only one of the possible positions of the fastener section, i.e. the fastener section of the thread  12  could have one of the following designs: 
         [0059]    a) it is located at the side of the flange section  40  remote from the piercing section  18 , 
         [0060]    b) it is located at the side of the flange section  40  remote from the piercing section  18  and extends at least partly into the flange section  40 , 
         [0061]    c) it is located at the side of the flange section  40  remote from the piercing section  18  and extends through the total axial thickness of the flange section  40 , 
         [0062]    d) it is located at the side of the flange section  40  remote from the piercing section  18  and extends through the total axial thickness of the flange section  40  and also through a part of the axial length of the piercing section  18 , 
         [0063]    e) it is located at the side of the flange section  40  remote from the piercing section  18  and extends through the total axial thickness of the 
         [0064]    10 flange section and also through the total axial length of the piercing section  18 , 
         [0065]    f) it is located at the side of the flange section  40  adjacent the piercing section  18  and extends through a part of the axial thickness of the flange section  40  and also through a part of the total axial length of the piercing section  18 , 
         [0066]    g) it is located at the side of the flange section  40  remote from the piercing section  18  and extends through a part of the axial thickness of the flange section  40  and also through the total axial length of the piercing section, 
         [0067]    h) it is located at the side of the flange section  40  adjacent the piercing section  18  and extends only through the total axial length of the piercing section  18 , 
         [0068]    i) it is located at the side of the flange section  40  adjacent the piercing section  18  and extends only through a part of the total axial length of the piercing section  18 . 
         [0069]    The fastener section  13  need not be provided from the outset with a thread  12 , but rather a smooth bore could be present here which is subsequently provided with a thread, for example in that the thread is formed when screwing in a thread-forming or thread-cutting screw. 
         [0070]    As is evident from  FIG. 1A , the ring groove  21  is not only bridged in the radial direction by the ribs  26  providing security against rotation, but rather these also extend in raised manner in the axial direction along the piercing section  18  up to the top side  35  of the ring bead  32 . A rounded shape is preferably present at the transition between the radially extending region of the ribs providing security against rotation and the axially extending region of these ribs providing security against rotation radially within the ring bead  21 . 
         [0071]    In this example the undersides  29  of the ribs  26  providing security against rotation are set back slightly from the ring-like contact surface  20 , for example by approximately 0.02 mm. The distance “d” between the ring-like contact surface  20  and the apex point of the ring bead  32  amounts, for example, to 0.3 mm in an element with an M8 thread. Furthermore, in this example, the maximum transverse dimension of the ring bead  32  amounts to 13.3 mm, the diameter of the cutting edge to 13.5 mm and the diameter in the base region of the ring groove  34  to 12 mm. The suitable sheet metal part could, for example, have a thickness in the range between 0.6 mm and 4 mm, for example 1.7 mm. 
         [0072]    The terms top side, underside, etc. as used here relate solely to the geometrical representation in the Figures and do not represent any restriction of the spatial arrangement of the functional element. 
         [0073]    The attachment of the functional element in accordance with  FIGS. 1 ,  1 A to a plate-like component will now be explained. The term “plate-like component” admittedly includes primarily sheet metal parts, the use of the functional element of the invention is, however, in no way restricted to the use with sheet metal parts. 
         [0074]    Instead of this, the component  22  could consist of plastic or it could solely represent a wall region of a cast part which is of plate-like shape in the region of the attachment of the functional element. The functional element in accordance with the invention could also be used with sandwich components, i.e. with components which are described in the EP application 01 927 10 700.3. The plate-like component could also be a component which consists of plastic with a sheet metal insert in the region of the attachment of the functional element. 
         [0075]    With reference to  FIG. 2 , it is evident that the sheet metal part  22  is supported on a die button  60  which has a bore  62  with a diameter D which is designed to receive the ring-like cutting edge  30  of the piercing section  18  of the fastener element  10 . That is to say, the diameter D of the die button is fractionally larger than the diameter of the ring-like cutting edge  30 . 
         [0076]    The bore  62  of the die button  60  is surrounded by a ring projection  64  which merges at the side radially remote from the bore into a surface  66  perpendicular to the longitudinal axis  68  of the bore, with the longitudinal axis  68  of the bore being at least substantially aligned with the longitudinal axis  14  of the fastener element  10 . 
         [0077]    The functional element  10  is, as is schematically illustrated in  FIG. 2 , received in a setting head  70  with a plunger  72  which acts on the ring-like pressing surface  24  and with a tubular housing part  74  which forms a receiver  73  for the fastener element  10 , the housing part surrounding the jacket surface  41  of the flange section  40  and centring the functional element with reference to the die button ( 60 ). 
         [0078]    The setting head  70  is arranged in known manner at the upper tool of a press (not shown) and is designed in the customary way and means so that the respective nut element  10  is received in the recess  73  of the setting head before the setting head  70  is moved with the upper tool of the press in the direction of the arrow  82  towards the sheet metal part  22 . The recess  73  can, for example, be equipped with magnets (not shown) in order to hold the functional element  10  which is, for example, placed into the recess by a robot. In this connection the die button  60  is arranged in a lower tool  76  of the press which is, for example, installed on an intermediate plate of the press or on the press table. It is also possible to install the setting head  70  at the intermediate plate of the press and to accommodate the die button  60  in a lower tool at the press table. It is likewise possible to arrange the setting head  70  in the lower tool  76  of the press so that the end face opening of the recess  73  faces upwardly instead of downwardly and then to arrange the die button  60  at the intermediate plate of the press or at the upper tool of the press. The setting head  70  and/or the die button  60  can also be carried by a robot or be installed in a C-frame with feed for the die button and/or the setting head. 
         [0079]    In the embodiment of  FIG. 2 , the setting head  68  is shown as a solid setting head with a plunger  72  fixedly arranged in the housing. 
         [0080]    The design of the setting head  70  can, however, take place precisely in the manner shown in  FIGS. 24 to 38  of EP-B-755 749 as an alternative to the illustrated variant. An embodiment of this kind has the advantage that the functional elements  10  can be guided into the recess of the setting head via a feed passage and can then be pressed by the means of the plunger against the sheet metal part. 
         [0081]    On closing the press, the functional element  10  moves, after insertion of the sheet metal part into the press above the die button, from the position which is shown at the left hand side of  FIG. 2  continuously closer in the direction of the sheet metal part, where, as shown at the right hand side of  FIG. 2 , the lower end face  28  of the piercing section  18  has just started to cut a circular piercing slug  18  out of the sheet metal part together with the ring projection  64  of the die button which supports the sheet metal part  22 . The piercing slug  80  falls through the bore  62  of the die button into the region of the enlarged bore  63  and can then be disposed of out of the die button in known manner. 
         [0082]    With complete closure of the press (or of the gripping tongs of a robot or of the actuating device of a C-frame), the functional element is then located with respect to the sheet metal part in the position in accordance with  FIG. 3 . That is to say, simultaneously with the cutting out of the piercing slug  80  or thereafter, through the movement of the body part  16  towards the sheet metal part  22  and the die button  60 , the sheet metal material is shaped by means of the ring projection  62  into the ring groove  22  and around the ring bead  32 , whereby a form-locked connection is produced between the sheet metal part and the fastener element. 
         [0083]    In this connection, the sheet metal material is shaped around the flanks of the ribs providing security against rotation so that both in the region axially above the ring-like contact surface  20  and in the region between the apex point of the ring-like bead  32  and the base surface of the ring-like groove  21 , the sheet metal material surrounds the ribs providing security against rotation at least substantially. This leads to excellent values for the security against rotation. 
         [0084]    Although the foul&#39; shown for the ribs providing security against rotation is preferred, the features providing security against rotation can also be designed differently. They could, for example, be formed by noses which are arranged on the conical surface or on the curved surface of the ring groove  22 , with it being possible to provide the noses, for example, only on the one flank  36  of the ring groove  21  or only on the other flank, i.e. in the rounded region of the ring groove  21  radially inside the bead  32 , or only in the base region of the ring groove. Moreover, the features providing security against rotation can be formed by recesses in the flanks and/or in the base surface of the ring-like groove as is, for example, shown by the broken line  84  in  FIG. 3 , with the sheet metal material then being shaped into the grooves providing security against rotation. 
         [0085]    Through the displacement of the sheet metal material by the ring projection, the material is also driven radially inwardly against the apex of the ring-like bead so that a ring toe  86  arises, which is arranged in  FIG. 3  at the lower side of the ring bead. 
         [0086]    Since the ring bead  32  projects radially into the sheet metal material, an excellent pull-out/push-out resistance is achieved. 
         [0087]    One can furthermore see from  FIG. 3  that the ring surface  66  of the die but-ton  60  comes to lie at least substantially in the plane of the lower end face  28  of the piercing section. This signifies that, in the screwed on situation in which a further component is screwed onto the sheet metal material  22  from below, no special measures need to be taken in order to ensure that the sheet metal part  22  is clamped between the ring-like contact surface  20  and the screwed on component. If the piercing section  18  of the functional element  10  were to project further downwardly than the lower side of the component  22  in  FIG. 3  then a corresponding recess would, for example, have to be provided in the component to be screwed into place in order to ensure that the clamping forces act between the functional element  10  and the screwed on component via the sheet metal part  22  and to prevent the sheet metal part so to say lying loosely between the body section  16  or the functional element and the screwed on component, which would be the case if the component were only supported at the lower end of the piercing section  18 . 
         [0088]      FIG. 3  shows the screwed on situation with a relatively thick sheet metal part  22 . If an even thicker sheet metal part is used, then the excess sheet metal material can further fill out the ring recess  34  whereby an even firmer attachment of the functional element to the sheet metal part  22  is made possible, since the lower side of the ring recess also contacts the sheet metal material in form-locked manner and thus increases the value of the pull-out/push-out resistance. Through the increased friction area between the sheet metal material, the resistance against rotation is also increased. 
         [0089]    If, however, a thinner sheet metal part is used, then no ring toe  86  arises, but rather the sheet metal material engages into the ring groove  21  only in the region above the ring bead  32 . 
         [0090]    Since a good overlap is also present here between the ribs providing security against rotation and the sheet metal material, or between the features providing security against rotation in the sheet metal material when the features providing security against rotation are formed by noses and/or recesses, a very good resistance against rotation is also achieved with thin sheet metal. 
         [0091]    In this embodiment a good pull-out resistance and press-out resistance is, however, also achievable because the bead  32  now engages at the lower side of the sheet metal material which is shaped into the ring groove  21 . 
         [0092]    One can see from this explanation that one and the same functional element can be used for sheet metal parts with various thicknesses which reduces the storage and ultimately the manufacturing costs. 
         [0093]    For the different sheet metal thicknesses, it is only necessary to provide different die buttons, the ring projections of which are dimensioned such that the sheet metal material always flows into the ring groove  22  and around the ring bead  32 . By determining the excess dimension by which the lower end face of the housing  74  of the setting head  70  projects downwardly below the ring-like contact surface  20  of the functional element, it can also be ensured that, in the in-built situation, the lower side of the sheet metal part always lies approximately in the plane of the end face  28  of the functional element or slightly below it. If necessary washers can also be used with very thin sheet metal parts which are arranged between the sheet metal part  22  and the component to be screwed into place, in order to ensure that the sheet metal part  22  is always clamped in orderly manner between the body part  16  of the functional element  10  and the component screwed into place. 
         [0094]    If the component to be screwed into place is a flange of a housing or the like, then the flange can be provided with a stepped bore in the event that the piercing section projects below the underside of the sheet metal part, with the stepped bore receiving the piercing section and also ensuring that the sheet metal part is clamped in an orderly manner via the component between the body section  16  or the functional element  10  and the head of the bolt that is used. 
         [0095]    In all these embodiments the sheet metal material in the region of the fastener element is pressed flat radially outside of a recess  88  caused by the ring projection  64  of the die button. Furthermore, the sheet metal material is at least partly shaped to a ring groove  90  at least partly surrounding the bead  32 . 
         [0096]      FIG. 4  shows an alternative representation of a functional element in accordance with the invention which in this example is attached to a relatively thin sheet metal part. 
         [0097]    The functional element of  FIG. 4  deviates from the functional element in accordance with the previous embodiments to the extent that the body section  16  is not provided here with a radially projecting flange part  40 . Furthermore, the fastener section  12  of the functional element in accordance with  FIG. 4  here not only extends within the body section  16 , but rather also into the piercing section  18 , so that the cylindrical hollow space  48  of  FIG. 1  is missing here and the thread  12  is bounded at its lower end solely by a conical surface  46 . The ring-like cutting edge  30  merges in this example into the ring recess  34  not via a cylindrical surface, but rather via a conical surface which extends at least substantially parallel to the conical surface  46 . 
         [0098]    Through a suitable shaping of the housing of the setting head (not shown here) and also of the end face of the die button (likewise not shown), the sheet metal material is shaped in this embodiment into a clear conical shape  92 , which ensures a very stiff attachment of the functional element  10  to the sheet metal part  22 , and moreover ensures that the lower side  96  of the sheet metal part lies slightly below the lower end face  28  of the piercing section  18  of the functional element. In the screwed on situation, the clamping forces which are produced between the functional element  10  and a component screwed on from below admittedly extend here through the conical shape  92  of the sheet metal part  22 . This is, however, nevertheless a very stable arrangement because the clamping forces attempt to press the sheet metal part  22  flatter in the region of the conical shape  92 , whereby this region is stiffened and on the whole a very stiff attachment is present. It is also possible, as likewise shown in  FIG. 4 , to provide the component  94  which is to be screwed into place with a corresponding shape  96  in the region of the pronounced ring recess of the conical shape and to attach the component by a bolt  100  to a sheet metal part. 
         [0099]    One also sees from  FIG. 4  that it is always possible with a suitable choice of the shape of the ring projection of the die button to ensure that sheet metal material surrounds the ring-like bead  32  and is also shaped into the ring recess  34 , whereby the above-mentioned resistance values for the security against rotation and for pull-out and press-out can be increased. 
         [0100]    It is also schematically indicated in  FIG. 4  how a component  94 ′ can be screwed onto the top side of the functional element which is basically also possible. 
         [0101]    Since, in this functional element, the piercing section  18  of the functional element is not deformed on the attachment of the sheet metal part  22 , it need not be feared that the fastener section, for example the thread  12 , is deformed during the attachment, which is why the thread  12  can straight-forwardly extend into the piercing section  18 . 
         [0102]    A design in accordance with  FIG. 5  is also conceivable in which the diameter of the ring-like cutting edge  30  is significantly smaller than the diameter of the imaginary cylindrical surface  106  at which the apex points  31  of the ring bead  32  lie. Here, through a suitable shape of the ring projection of the die button, it can also be ensured that the sheet metal material is not unnecessarily thinned and weakened in the region between the ring projection  64  of the die button  60  and the ring bead  32 . In the embodiment of  FIG. 5 , no ring recess is present, but rather the piercing section  18  is at least substantially cylindrical in the lower region. 
         [0103]    Using a die button (not shown) similar to the die button  60 , the sheet metal material is first drawn in the example of  FIG. 5  between the cutting edge  30  and the ring projection  64 , which has a diameter larger than that of the ring bead  32 , to faun a conical recess and the piercing slug is subsequently cut out from the base region of the conical recess. Thereafter the ring projection  64  pushes the sheet metal material, which is supported at the top and at the ring projection, into the axial ring groove  21  and also towards the apex of the ring bead by means of a preferably obliquely inwardly pointing flank. The ribs providing security against rotation moreover lead to a displacement of the sheet metal material into the radially extending region of the axial ring groove  21  above the ring bead  32 . 
         [0104]    It will now be explained with reference to  FIGS. 6 to 10  how a functional element  10  of the above-described kind can be manufactured. This description is admittedly concerned with a slightly modified form of the functional element of  FIG. 4 , which is shown in its own right in  FIG. 10 , but the description also applies to all further described variants. 
         [0105]    Before the manufacturing steps of  FIGS. 6 to 9  are discussed, it is appropriate to explain the specific embodiment of  FIG. 10  in more detail. 
         [0106]    In this explanation the same reference numerals will be used for features or parts which have the same shape or function as in the previous embodiments and it will be understood that the previous description (as in all Figures) applies equally to such features or parts unless something different is expressed. 
         [0107]    The special feature of the functional element of  FIG. 10  lies, on the one hand, in the fact that the body section  16  has at least substantially the shape of the body section  16  of the embodiment of  FIG. 4 , but that the ring-like bead  32  here consists of four thread sections  32 ′,  32 ″ which merge into one an-other, with the two further thread sections not being seen because they lie at the rear side of the element  10  shown in  FIG. 10 . 
         [0108]    As is evident from  FIG. 10 , the ring-like bead section  32 ′ at the left hand side of the axis of symmetry (in this case the longitudinal axis  14  of the functional element) is formed as a left hand thread section and extends over 90° around the axis of symmetry whereas, at the right hand side of the axis of symmetry, the ring-like bead is formed as a section of the right hand thread which likewise extends over an angle of 90° around the central longitudinal axis. 
         [0109]    At the rear side of the functional element in  FIG. 10 , a right handed thread section is formed at the left hand side of the ring-like bead  32  and on the right side a left handed thread section is formed, in both cases over an angular amount of 90° about the central longitudinal axis  14 . That means that the bead also represents a closed ring here, but with a type of wave-shape in the peripheral direction. 
         [0110]    This also leads to a situation in which the axially extending parts  26 ″ of the ribs  26  providing security against rotation, which turn out to have different lengths down to the bottom of the ring groove  21  (see also  FIG. 5 ), which can easily be recognized with respect to  FIG. 10 . 
         [0111]    Although the ring-like bead  32  has been formed in the previous description as a closed ring this is not essential. The ring-like bead could also be formed by bead sections which are spaced from one another in the peripheral direction (not shown). This would also lead to an increase of the security against rotation. 
         [0112]    The ring-like bead  32  could also be formed only by sections of left handed threads or right handed threads which are disposed overlappingly or with a spacing around the periphery of the piercing section. 
         [0113]    For the manufacturing of a functional element in accordance with  FIG. 10 , a cylindrical blank  120  in accordance with  FIG. 6  is first taken and is so de-formed in a first cold heading stage that the cylindrical blank adopts the shape which is shown by continuous lines in  FIG. 6 , i.e. the cylindrical blank in  FIG. 6  retains its original diameter in the lower region  122 , but is formed into a thicker cylinder  124  in the region above the plane  126 , and indeed with a recess  128  in the upper end of the cylinder. This shape can then be brought by further cold heading steps closer to the envelope shape in accordance with  FIG. 7  with the axially extending ring groove  21  being formed with the ribs  26  providing security against rotation in accordance with  FIG. 7 , and with a significant recess or an indent  130 ,  132  being formed in the upper end face and in the lower end face of the blank respectively. The corresponding indents  130 ,  132  can also be manufactured in several steps starting from  FIG. 6  or, if the material permits it, can be introduced in only one step, starting from  FIG. 6 , into the shape of  FIG. 7 . Thereafter a further upsetting process takes place which leads to the formation of the ring bead  32  in accordance with  FIG. 8 . The special shape of the ring bead in accordance with  FIG. 8 , which corresponds to the course of  FIG. 10 , is, on the one hand, favored by the shaping of the cold heading tool, which is moved into the axial direction coming from below in  FIG. 8 , but can, however, also, if required, be favored by tool segments which engage in the radial direction between the ring-like contact flange and the ring bead and also have a corresponding shape. 
         [0114]    In a further step, the region between the two indents  130 ,  132  is then pierced in order to produce the cylindrical region  12 ′ in accordance with  FIG. 9  which is later provided with a thread. 
         [0115]    In the same step, or separate from it, the cylinder projection  136  of  FIG. 8  is also so compressed by the cold heading tool that the ring-like cutting edge  130  and the ring recess  34  in accordance with  FIG. 9  arise. One can see from  FIG. 9  that the outer diameter of the ring-like cutting edge  30  is somewhat smaller than the diameter of the imaginary cylinder ( 106 —only shown in  FIG. 5 ) on which the apex  31  of the ring bead  32  lies. This is also an entirely permissible design of the functional element since it can be ensured through the shaping of the die button  60  and in particular of the ring projection  64  that the sheet metal material is not cut through by the die button in the region of the ring bead. 
         [0116]    It is, however, also possible that the cold heading process, which leads to the formation of the ring-like cutting edge  30 , also produces the shape of  FIG. 10  where the outer diameter of the ring-like cutting edge is somewhat larger than the diameter of the said cylinder  106  which the apex  31  of the ring bead  32  contacts. This avoids, as is evident from  FIG. 3 , a situation in which the ring projection thins the sheet metal material to too large a degree in the region from the edge  30  and the apex  31  of the ring bead  32 . 
         [0117]    Finally, it should also be pointed out that for the sheet metal part all steel or aluminium or magnesium sheet metal parts can be considered which have deep drawing qualities, whereas somewhat stronger materials are used for the functional element. 
         [0118]    In all embodiments all materials can also be named as an example for a material of the functional element which achieve the strength values of class 8 or higher in accordance with the ISO standard in the context of cold deformation, for example a 35B2 alloy in accordance with DIN 1654. The thus formed fastener elements are also suitable amongst other things for all customary traded steel materials for drawing quality sheet metal parts as also for aluminium and its alloys. Also aluminium alloys, in particular those of high strength, can be used for the functional elements, e.g. AlMg5. Also functional elements of higher strength magnesium alloys such as for example AM50 can be considered.