Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P19/00—Machines for simply fitting together or separating metal parts or objects, or metal and non-metal parts, whether or not involving some deformation; Tools or devices therefor so far as not provided for in other classes
  • B23P19/04—Machines for simply fitting together or separating metal parts or objects, or metal and non-metal parts, whether or not involving some deformation; Tools or devices therefor so far as not provided for in other classes for assembling or disassembling parts
  • B23P19/06—Screw or nut setting or loosening machines
  • B23P19/062—Pierce nut setting machines
  • B23P19/064—Deforming the support material only, e.g. the sheet or plate
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
  • B21K25/00—Uniting components to form integral members, e.g. turbine wheels and shafts, caulks with inserts, with or without shaping of the components
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B37/00—Nuts or like thread-engaging members
  • F16B37/04—Devices for fastening nuts to surfaces, e.g. sheets, plates
  • F16B37/06—Devices for fastening nuts to surfaces, e.g. sheets, plates by means of welding or riveting
  • F16B37/062—Devices for fastening nuts to surfaces, e.g. sheets, plates by means of welding or riveting by means of riveting
  • F16B37/068—Devices for fastening nuts to surfaces, e.g. sheets, plates by means of welding or riveting by means of riveting by deforming the material of the support, e.g. the sheet or plate
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
  • F16B35/04—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws with specially-shaped head or shaft in order to fix the bolt on or in an object
  • F16B35/06—Specially-shaped heads

Definitions

• the invention relates to a method for producing a press-fit connection between a fastening element and a metallic component, and to such a press-fit connection and to a fastening element for such a press-fit connection.
• fasteners such as screws, nuts, bolts, etc. must be permanently attached to components such as sheet metal, extruded profiles or cast parts.
• components such as sheet metal, extruded profiles or cast parts.
• two technologies generally play an important role in permanently connecting a fastener to a component such as sheet metal.
• These technologies are welding and mechanical connection technology, specifically the creation of a press-in connection, in which a press-in element is pressed into a component and held there permanently.
• the fastening element and the metal sheet are permanently connected to one another by melting certain areas of both components through the application of heat, so that a material connection between the fastening element and the metal sheet is created.
• press-fit methods sometimes disadvantageously require that a hole be made in the component.
• the connec tion is often not gas-tight, especially when there are high pressure differences between the top and bottom of the sheet metal. Additional sealing elements have to be used to seal it.
• the invention is based on the object of enabling a connection between a fastening element and a component which is gas-tight and in which a head region of the press-in element does not protrude beyond a component side.
• the object is achieved according to the invention by a method for producing a press-in connection between a fastening element, in particular a press-in bolt and a component, in particular a metal sheet, the fastening element having a head and being pressed head first into the component with the aid of a punch without penetrating the component.
• the material of the component is first displaced from the head, in particular radially outwards, with at least and preferably only part of the displaced material being pressed radially by the stamp against the head, so that a form fit acting in the axial direction between the against the Head pressed material and the head is formed.
• the object is also achieved by such a press-fit connection and a fastening element used for this purpose.
• the advantageous configurations listed below with regard to the method, the press-in connection and the fastening element can each also be transferred to the other two categories.
• a permanent connection is ensured by the material formed by the stamp and the form-fitting connection formed in the process.
• the fastening element does not pierce the component, there is no risk of leakage.
• the component is not pre-punched Component, so that the fastener opposite underside of the component is intact. This ensures tightness and the press-in connection is gas-tight. No additional sealing measures, such as a seal or a leak test, are required and are not provided.
• the fastening element is preferably introduced directly into the (ductile) component, in particular sheet metal, without the component being pretreated, e.g. by forming a hole or forming.
• an overhang on the underside of the typically thin component is preferably avoided, i.e. the underside of the component also remains undeformed, i.e. it is not deformed during the pressing-in process.
• the bottom is flat. Therefore, this method offers a solution for tight and constrained geometries.
• the fastening element is designed overall as a press-in element which, as described, is pressed into the component by a corresponding press-in force.
• the fastening element is in particular a bolt-shaped element, ie either a bolt, a screw, a pin, a rivet, etc.
• the bolt-shaped element has a shank with the head adjoining it at the end.
• the fastening element is, for example, a nut with an internal thread.
• the head has a head side which is oriented towards the component and has a central region which protrudes in the axial direction.
• the head is first pressed against the component with this central area and, starting from the central area, the material of the component is displaced radially outwards during the further pressing-in process.
• This geometry with the protruding center area advantageously reduces the required press-in force.
• the press-in tools such as stamps and a drive for applying the press-in force, can have more compact dimensions. be oned. This also increases process reliability, since the material of the component is pushed outwards in a controlled and defined manner through the protruding central area.
• the axial direction is also the press-in direction and the longitudinal direction of the fastening element along a central axis, starting from the shank in the direction of the head.
• the head side is convexly curved. It is therefore arc-shaped when viewed in cross-section and runs, in particular, along a segment of a circular arc. In particular, it forms a convex curved surface. In particular, the head side is designed in the shape of a lens.
• the head side is formed by several planar surfaces and, for example, in a facet-like manner. It is example, designed in the manner of a pyramid or a truncated pyramid. A conical configuration is also possible.
• anti-rotation elements are also formed on the head, which together with the material of the component form a form fit acting in the circumferential direction.
• the head therefore has a dual function and, when pressed in, offers both an axial pull-out protection and an anti-twist protection.
• the anti-twist elements are either elements protruding from the head or indentations. These are arranged around the circumference in particular evenly distributed. For example, 3-10 and in particular 4-8 anti-rotation elements are formed.
• the anti-rotation elements are formed on the head side, in particular as a plurality of radial ribs.
• the anti-rotation elements are designed, for example, as radial notches or grooves.
• the press-in elements formed on the head end preferably only extend in a radially outer area of the head end, so that in a central area of the head end, especially in the protruding central area, with which the head end first strikes the component during the press-in process, there are no anti-rotation protection elements, in particular no ribs are formed.
• anti-rotation elements are formed around the peripheral edge of the head.
• they are specially designed as indentations, for example as concave indentations.
• the indentations have, for example, a part-cylindrical wall.
• an anvil is provided as a counter bearing during the press-in process, which has a flat surface surface.
• the contact surface is flat throughout and has no depressions, elevations or openings.
• the anvil thus forms a die with a continuously flat contact surface without depressions, elevations or openings.
• a special design of the stamp is provided for the reliable form-fitting connection of the fastening element to the component.
• This has a radially inner pressing ring, with which it is pressed against a pressure surface formed on the underside of the head and exerts the required axial press-in force via this surface.
• the punch is a hollow punch having an internal cavity for receiving the shank of the bolt.
• the front side of the press ring is formed, which the inner cavity annularly encircles.
• the pressing surface is designed to correspond in particular to this. i.e. it is in particular also ring-shaped.
• a shoulder protruding in the direction of the shaft is formed on the underside of the head, the end face of which forms the annular pressing surface.
• the stamp also has a forming section arranged radially further outwards, with the aid of which the material initially displaced radially outwards from the head is pressed again in the radial direction to the head and in particular in the direction of the shaft.
• this forming section directly adjoins the pressing surface. It is preferably inclined in the direction of the shank and thus in the direction of the inner cavity, so that a circumferential inclined forming surface is formed, which exerts a radial force component on the material of the component in the direction of the inner cavity and thus the shank.
• this peripheral surface is either straight and thus conical or curved.
• the forming surface is designed in the manner of a conical surface.
• the stamp preferably has a cutting ring at its front end, which is preferably designed with sharp edges or alternatively also with a rounded shape. During the pressing process, he uses this to cut into the surface of the component and specifically into the material that has been displaced to the outside.
• the cutting ring forms the ra dial outer end of the forming section, so connects to this in the radial direction.
• the forming surface described above encloses an acute angle with an outer lateral surface of the punch, which is designed in particular as a cylindrical lateral surface. This is for example in the range between 30° and 60°.
• the head geometry of the head and the geometry of the stamp are matched to one another in such a way that during the pressing-in process, material of the component is initially displaced radially outwards before the forming section reaches the component surface.
• the head has an axial height that is greater than the axial extension of the ram from the compression ring to the axially foremost partial area of the ram, which is formed in particular by the cutting ring.
• the axial height of the head is defined by the axial distance between the pressing surface and the front part of the head side.
• the head has a circumferential pull-out surface that protrudes radially outwards. This connects in ra dialer direction in particular to the shoulder previously described.
• the shoulder generally has on its end face the aforementioned pressing surface and an in particular cylindrical lateral surface extending in the axial direction. The pull-out surface is therefore designed offset from the shoulder and specifically from the pressing surface.
• the material initially displaced by the head is again pressed radially inwards and over the extraction surface by means of the punch, so that the form fit acting in the axial direction is formed.
• the material is only pressed over the extension surface.
• a free space is preferably left in relation to the lateral surface of the shoulder.
• the head therefore has two sub-areas, namely a first sub-area oriented towards the shank, which is formed by the shoulder and a second sub-area facing away from the shank, which protrudes radially beyond the first sub-area and thus serves to prevent the head from being pulled out axially and which also has the front, having the end face with the central area protruding forward.
• the anti-rotation elements are preferably also formed on this second partial area.
• the shoulder preferably only has smooth surfaces.
• it is designed overall as a circular ring cylinder with a smooth lateral surface and a planar pressing surface.
• the method as a whole is preferably characterized by the following steps, which in particular follow one another in the order mentioned: i. applying a force to the punch, ii. joint feeding of the stamp and the fastening element to the component with the simultaneous exertion of a force, iii. plastic deformation of the component by the head of the fastener, in particular by the protruding central area, IV.
• the press-in connection formed in this way between the fastening element and the component is initially distinguished by the fact that the component is not perforated and is also preferably not otherwise pretreated.
• the fastening element is pressed headfirst into the component without piercing it, with the material displaced by the head during the pressing process being deformed again towards the head and thus forming a form fit with the head.
• the head preferably has a front head side with a protruding central area which is designed in particular in the shape of a lens.
• the component is planar and flat on its underside opposite the fastening element, ie it has no bulging or other deformation.
• the fastening element provided for such a press-in connection and for such a method is characterized in particular by the fact that its head has a protruding central area.
• the head side is designed in particular special lens-shaped. Viewed in cross section, the head side runs in particular along a radius.
• the fastening element also has the anti-rotation elements described above, which are formed on the head.
• the anti-rotation elements are formed on the head side, i.e. on the front side of the fastening element. They are specifically designed as ribs or notches that extend in the radial direction.
• anti-rotation elements in particular in the form of indentations, are formed on the circumference of the head.
• the fastening elements preferably only extend in an outer radial area of the head side and do not extend as far as the middle. In the central area, the head side is therefore particularly free of anti-rotation security elements.
• a preferred further development provides that they do not protrude beyond the central area of the head side in the axial direction. This ensures that during the press-in process, the protruding central area of the head first hits the surface of the component and the plastic deformation is unaffected by the anti-rotation elements.
• the axial extent of the anti-rotation elements ie an axial height in the case of ribs and an axial depth in the case of notches, varies in the radial direction and in particular increases continuously. In the case of the ribs, the increase is from the inside out. In the case of notches or grooves, the opposite is true. Furthermore, it is provided in particular that a front face of the ribs facing away from the head side or a groove base of the notches runs horizontally, that is to say perpendicularly to the axial direction.
• the fastening element is preferably designed as a bolt-shaped element with a shank, to which the head is connected at the end, the head having a head side opposite the head underside, on which a shoulder is formed, which directly adjoins the shank in the radial direction closes and which forms a pressing surface for the transmission of an axial pressing-in force, with a pull-out surface adjoining the shoulder in both the axial and radial directions.
• This configuration ensures a process-reliable pressing-in with reliable axial protection against being pulled out.
• FIG. 1 is an exploded perspective view showing a fastener, a component, and a punch and anvil;
• FIG. 2 shows a side view of the fastening element according to a first variant
• FIG. 3 shows a plan view of the fastening element according to FIG. 2;
• FIG. 4 shows a perspective view of the fastening element according to FIG. 2;
• FIG. 5 shows a plan view of the situation during the pressing-in process
• FIG. 5A shows a sectional view along the line 5A-5A in FIG. 5 through the fastening element, the component, the punch and the anvil at the start of the press-in process;
• FIG. FIG. 5B shows a detailed view of the area 5B in FIG. 5A;
• FIG. 6 shows a sectional view like FIG. 5A at a later point in time of the pressing-in process
• FIG. 7 shows a sectional view like FIG. 5A at an even later point in time of the press-in process
• FIG. 8 is a detailed view of area 8 in FIG. 7;
• FIG. 9 is a perspective view of a metal sheet with a press-in element attached;
• FIG. 10 shows a side view of the arrangement according to FIG. 9;
• FIG. 11 shows a plan view of the arrangement according to FIG. 9;
• FIG. 12 perspective views of the fastening element according to a second variant
• FIG. 13A, B perspective views of a fastening element according to a third variant, in which ribs are formed on an end face of the head;
• FIG. 14A-C Sectional views showing various steps in making the press fit connection. DETAILED DESCRIPTION OF THE FIGURES
• FIG. 1-14 show the method for producing a press-in connection between a fastening element 200 and a ductile component, namely a metal sheet 300.
• Figure 1 shows the components used to form the press fit connection without pre-punching. These components are a punch 100, the sheet metal 300, the fastening element 200, which is designed in particular as a screw, and an anvil 400.
• the stamp 100 is cylindrical in the exemplary embodiment and has an inner hollow space 105 .
• the punch 100 extends in an axial direction A along which the fastening element 200 also extends and along which it is pressed into the metal sheet 300 .
• a shank 201 in the exemplary embodiment a threaded shank, is received by the inner cavity 105 and, together with the stamp 100, is pressed into the metal sheet 300 and against the anvil 400 arranged underneath.
• the fastening element 200 has a head 207 with a front end-face gene head side 204, which is curved in the axial direction A, ie to the side facing meet the shank 201 forward and there so forms a protruding Mittenbe rich.
• the head face 204 has a front radius. With this, i.e. with the protruding central area, the fastening element 200 comes into contact with the metal sheet 300 for the first time.
• FIG. 2-4 show various views of fastener 200.
• the threaded shank is for releasable attachment to another fastener (e.g., a nut in this case).
• Essential geometric details of the fastening element 200 are shown in FIGS. 2-4 to recognize.
• the shank 201 connects counter to the axial direction A.
• the head 207 has a shoulder 203 that runs annularly around the shaft 201 and forms an annular pressing surface 202 opposite the head side 204 .
• the side of the head 207 opposite the head side 204 and facing the shaft 201 is generally referred to as the underside of the head.
• the pressing surface 202 serves as a stamp contact surface, ie during the pressing-in process, the stamp 100 is supported by a corresponding pressing ring 102 (compare, for example, FIG. 5B) for transmitting the axial pressing-in force.
• the pressure ring 102 therefore forms a corresponding contact surface.
• the peripheral side of the shoulder 203 is formed out cylindrical in the embodiment.
• This shoulder 203 is followed by a second partial area of the head 207 which widens radially outward starting from the shoulder 203 .
• this second partial area widens conically and has an extension surface 206 inclined obliquely outwards, which is designed in the manner of a cone-shaped outer surface.
• the head side 204 adjoins this pull-out surface 206 on the face side.
• the pull-out surface 206 serves to form a grip behind a formed material area of the sheet metal 300 and thus to form the axial pull-out safeguard, as will be explained in more detail below, particularly in connection with FIGS. 5A and 5B.
• the underside of the head opposite the head side 204 therefore forms both the pull-out surface 206 and the pressing surface 202 .
• a plurality of anti-rotation elements 205 in the form of bulges are introduced. In the radial direction, these extend only a little way in the direction of the shaft 201, such that they are at a distance from the peripheral lateral surface of the shoulder 203.
• these bulges reach as far as the peripheral lateral surface of the shoulder 203.
• flat areas can also be formed.
• anti-rotation locking elements 205 are provided, distributed evenly around the circumference, specifically 3-8 and in the specific exemplary embodiment 6.
• the stamp 100 has a force absorbing surface 101 on its upper side in the exemplary embodiment, on which the pressing-in force is exerted by means of a suitable drive during the pressing-in process.
• a stamp 100 without (particularly planar) force receiving surface 101 is used.
• the fastening element 200 is fed to the stamp 100 from above, for example via a feed hose or a feed line.
• the stamp 100 typically has an annular force absorption surface.
• the special configuration of the end face of the stamp 100 can be seen from FIG. 5B.
• it also has an annular surface in the manner of a shoulder, which is formed at the end of the flea space 105, which forms the press ring 102 already mentioned. This is supported on the corresponding pressing surface 202 during the pressing-in process.
• the pressing ring 102 and the pressing surface 202 have essentially the same radial extent. to the ring-
• the surface of the pressing ring 102 is adjoined by a particularly cylindrical casing section which extends in the axial direction A and at least partially accommodates the shoulder 203 .
• the stamp 100 has a surface which extends obliquely and ra dial outwards and is in particular in the shape of a cone jacket, which forms a deforming section 104 .
• This extends to an outer press-in ring, which is designed as a cutting ring 106, for example. Its annular edge is, for example, rounded, as shown in FIG. 5B, or sharp-edged, as can be seen in FIGS. 14A to 14C.
• the press-in or cutting ring 106 defines the foremost surface of the punch 100 with which it first strikes the sheet metal 300.
• the axial length, starting from the annular surface of the compression ring 102 to this cutting ring 106, is less than the axial length of the head 207 and preferably only extends to the end of the shoulder 203.
• the metal sheet 300 has an upper side 301 facing the fastening element 200 and an opposite lower side 302 .
• the anvil 400 has an upwards, oriented to the sheet metal 300 flat support surface 401, which is continuously flat. In particular, it therefore has no depression or elevation.
• the pressing-in process begins with the application of a force to the plunger 100, for example to the illustrated (flat) force absorption surface 101 or alternatively to an annular force absorption surface.
• a force to the plunger 100, for example to the illustrated (flat) force absorption surface 101 or alternatively to an annular force absorption surface.
• the stamp 100 and the fastening element 200 together penetrate into the deformable metal sheet 300 .
• Sheet metal 300 is supported with its underside 302 on bearing surface 401 of anvil 400 .
• the protruding central area of the head side 204 first comes into contact with the upper side 301 of the component 300. From Of particular importance here is that due to the protruding central area at the beginning of the plastic forming process, there is only slight surface contact, in particular only point contact, between the head side 204 and the metal sheet 300, so that a very high surface contact pressure is exerted.
• this material bead 303 is completely formed. Specifically, the cutting area 106 engages in this formed material bead 303 . Material from the formed material bead 303 is then pressed in the radial direction towards the head 207 by the deforming section 104 . A closing bead 304 forms, as can be seen in particular in FIG. This closing bead 304 is pressed against the pull-out surface 206, so that a type of press fit is formed. A form-fitting undercut is formed between the pull-out surface 206 and the closing bead 304 for reliable protection against being pulled out.
• a stamp 100 is used in which the cutting ring 106 is formed with sharp edges. This preferably has a triangular profile at least in its front area facing the sheet metal 300 .
• the deformed section 104 is designed in profile as a curved, specifically concavely curved, surface. In principle, even with the first embodiment variant, as is the case, for example, As shown in Figures 5-8, such a bent forming section 104 may also be provided. This convexly bent deformed section has a favorable effect on the deformation. Especially in combination with the sharp-edged cutting ring 106, only low press-in forces and forming forces are required overall due to the selected punch geometry according to FIGS. 14A to 14C.
• the anti-rotation lock is also formed at the same time, in that the plastically deformed material forms a form fit with the anti-rotation lock elements 205 that is effective in the circumferential direction.
• the upper side 301 of the metal sheet 300 has a characteristic geometry, as can be seen in particular from FIGS. 7-11 .
• an annular and concentric circumferential groove is initially formed by the cutting ring 106 .
• This groove is adjoined radially inward by the closing bead 304 rising from a normal level of the upper side 301 .
• the underside 302 of the metal sheet 300 is not deformed at all and, in particular, is continuously flat in the area of the fastening element 200 .
• FIG. 9-11 show the press-fit connection between the fastener 200 and the ductile sheet 300.
• Another important point is that the process and the finished press-in connection enable a leak-proof application, especially for closed component spaces where pressurized or non-pressurized gases and liquids are present. Thanks to this permanent press-fit connection, no additional elements such as a gasket or sealant are required, i.e. the press-fit process simplifies production and reduces unit production costs.
• FIG. 12 shows an alternative variant of the fastening element 200. This differs from the first variant, as explained in relation to FIGS. This means the bulges are deeper. An improved anti-twist protection is achieved by flying.
• Ribs are a preferred embodiment of an anti-twist geometry.
• the ribs 205 extend in a radial direction Direction and are preferably formed uniformly around the circumference directly on the head side 204. It should be emphasized here that they are only formed in a radially outer partial area, so that the central area protruding in the axial direction A has no ribs 205 and the front surface area of the fastening element 200 is still rich.
• the ribs In the axial direction A, the ribs have a height which preferably increases radially outwards.
• a front end face or end edge of the respective rib 205 preferably runs at an axial height that is set back relative to the central area.
• the end face of the rib 205 runs horizontally, for example, ie perpendicularly to the axial direction A. All end faces preferably lie within a common plane.
• the Rip pen 205 have, for example, a triangular cross-sectional profile. 5 ribs 205 are shown as an example in FIGS. 13A, 13B. However, there can also be more ribs 205, such as 8 to 10 ribs.
• the fastening element 200 is preferably used for components 300 made of ductile materials such as aluminum alloys, copper alloys or steels.
• the fastening element 200 itself is preferably made of steel with a higher strength than the component 300. As a rule, the fastening element 200 is tempered to a tensile strength of at least 800 N/mm 2 , preferably 1000 N/mm 2 .

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Insertion Pins And Rivets (AREA)

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Publications (1)

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• 2022
  • 2022-02-17 CN CN202280027085.5A patent/CN117120730A/zh active Pending
  • 2022-02-17 WO PCT/EP2022/053915 patent/WO2022175375A1/de unknown
  • 2022-02-17 EP EP22706589.3A patent/EP4271922A1/de active Pending
• 2023
  • 2023-08-21 US US18/236,086 patent/US20230392640A1/en active Pending

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