WO2021160315A1

WO2021160315A1 - Joining element, connecting structure comprising said joining element, and corresponding connecting method

Info

Publication number: WO2021160315A1
Application number: PCT/EP2020/084539
Authority: WO
Inventors: Sergej Erbis; Marcel Uffelmann
Original assignee: Boellhoff Verbindungstechnik Gmbh
Priority date: 2020-02-11
Filing date: 2020-12-03
Publication date: 2021-08-19
Also published as: DE102020103488A1

Abstract

The invention relates to a joining element (1) for establishing a connection between at least two components, in particular a setting bolt. The joining element comprises: a head (10) at a first axial end; a tip at a second axial end opposite the first axial end; and a shaft (30) which is located between the tip and the head and defines a longitudinal axis of the joining element between the first and second axial ends. In cross-section along the longitudinal axis, the tip has a circular region (22) which is mirror-symmetrical with respect to the longitudinal axis and has a first radius r₁ adjacent to the shaft. The centre of the circular region lies on a perpendicular to the longitudinal axis of the joining element so that the tip tapers in the circular region in an ogival shape towards the second axial end. Furthermore, the tip has a convex circular end region having a second radius r₂ adjacent to the circular region, the centre of said end region being located on the longitudinal axis of the joining element adjacent to the second axial end. The ratio between the first radius r₁ and a diameter d_s of the shaft adjacent to the tip is as follows: 0.6 ≤ r₁/d_s ≤ 5.5.

Description

Joining element, connection structure with the joining element and a corresponding one

Connection procedure

1. Field of the invention

The present invention relates to a joining element for producing a connection between at least two components, in particular a setting bolt, a connection structure composed of at least a first and a second component connected by means of the joining element, and a method for connecting at least one first component to a second component by means of the joining element.

2. Background of the invention

Joining elements for establishing a connection between two components usually comprise a head, a shaft and a tip. The specific structure of the joining element depends on the desired area of application, so that joining elements are known in the prior art in a large number of different configurations.

DE 102006 002238 A1 describes the use of a nail as a joining element. The nail is driven in at high speed through the components that are not prepunched in the joining area so that the nail tip penetrates both components completely and a bulge-shaped material is formed in the component on the nail head side, which protrudes into an annular groove in the nail head and into the component facing away from the nail head Kraterformiger material bulge is formed, which protrudes in the opposite direction. An auxiliary welding joining part for connecting components is described in DE 102012010 870 A1. The auxiliary welding joining part is disclosed in the form of a bolt with a head, a shaft and a tip, wherein the tip can be designed, for example, ogival.

Further joining elements with ogival tips for producing a connection between two components are described in WO 2007/043985 A1 and US Pat. No. 5,658,109 A1.

The use of ogival tips is generally known for both joining elements and fastening elements. In contrast to joining elements, which are suitable for producing a connection between at least two components, fastening elements are fastened in a component. Since the tip of the joining elements is usually intended to penetrate the components that are not prepunched in the joining area during the production of the connection, this must be taken into account when designing the joining elements. With regard to the design, the aim of fastening elements is not to penetrate the component, but are adapted to penetrate a component.

For the sake of completeness, there is an example of a corresponding fastening element in US Pat. No. 2,751,808 A1. The fastening element described here has an ogival tip which is truncated spherically.

A disadvantage of the joining elements discussed above, as well as the fastening elements, becomes apparent when one of the components to be connected to one another is made of high-strength or ultra-high-strength steel, for example of press-hard steel. If such a steel is used, for example, for the lower component, i.e. as a component facing away from the head, the use of the joining elements and fastening elements explained above leads to an undesirable deformation of the tip of the elements and / or to a break in the element. The known geometry of the joining elements and the fastening elements therefore fails when placed in a component made of high-strength or ultra-high-strength steel that has not been pre-punched in the joining area, the tip of the element should completely penetrate both components.

In order to meet these special requirements for setting in a component made of high-strength or ultra-high-strength steel, DE 102014019 322 A1 describes the use of a joining element with a pointed area and a shaft area, the properties of which differ, the connecting element being designed in one piece . The pointed one The area has a higher strength than the shank area, so that the pointed area can also penetrate ultra-high-strength steels without plastic deformation of the pointed area.

A disadvantage of this design, however, is the undesirable formation of a slug when it is placed in the high-strength or ultra-high-strength steel.

The object of the present invention is therefore to provide a joining element that is optimized compared to the prior art, with which it can be set in a component made of high-strength or ultra-high-strength steel without failure of the joining element, ie deformation of the tip area and / or breakage of the joining element is also possible without separating a slug.

3. Summary of the Invention

The above object is achieved by a joining element for producing a connection between at least two components according to independent patent claim 1, a connection structure according to independent patent claim 11 and a method for connecting at least one first component to a second component according to the independent patent claim - Claim 13. Advantageous embodiments and further developments result from the following description, the drawings and the appended claims.

A joining element according to the invention for establishing a connection between at least two components, in particular a setting bolt, comprises a head at a first axial end, a tip at a second axial end opposite the first axial end and a shaft arranged between the tip and the head, the one The longitudinal axis of the joining element is defined between the first and the second axial end, the tip having, in cross section along the longitudinal axis, a circular area mirror-symmetrical with respect to the longitudinal axis with a first radius r ₁ adjacent to the shaft, the center of which is perpendicular to the shaft The longitudinal axis of the joining element lies so that the tip in the circular area tapers in an ogival shape to the second axial end, and the tip has a convex circular end area with a second radius r ₂ following the circular area, the center of which is adjacent to the longitudinal axis of the joining element rt is arranged to the second axial end, for a ratio between the The following applies to the first radius r ₁ and a diameter d _{S of} the shaft adjacent to the tip: 0.6 r ₁ / d _S 5.5.

The joining element according to the invention thus comprises, in a known manner, a head, a shaft and a tip. In particular, the tip and the shaft are preferably designed in one piece. The joining element is particularly preferably designed as a single piece, i.e. the head, the shaft and the tip. Likewise, the joining element preferably consists of only one material. This is especially true for the shaft and the tip. This means that the joining element according to the invention preferably has no additional coating or a further material layer on the outside.

The extension of the shaft between the head and the tip also defines the longitudinal axis of the joining element between the first and the second axial end in the usual way, which is also referred to as the central longitudinal axis due to its position and course. The shaft is preferably cylindrical. The core diameter is preferably used as the diameter of the shaft. With reference to a one-piece shaft with a surface profile, it is therefore the smallest diameter of the shaft. For example, based on a thread as a possible surface profile in the shank area, the core diameter thus designates the distance between the inner points of the thread or the surface profile, measured perpendicular to the longitudinal axis.

The special feature of the design of the joining element according to the invention arises with regard to the design of the tip. In summary, this has a first ogival area adjacent to the shaft and an adjoining spherical area, the radius r _{1 of} the ogival area or of the area, which is circular in cross section along the longitudinal axis, a certain ratio to the diameter of the to solve the task defined above Has shaft, which will be explained below.

An ogival body or area is created by an arc segment that is rotated 360 ° around a central axis. If such a body or area is viewed in cross section along the central axis, the corresponding circular arc segment is mirror-symmetrical to the central axis. An ogival shape is therefore a body of revolution. In relation to the joining element according to the invention, such an ogival area is defined by the circular area with the first radius r ₁ present in cross section along the longitudinal axis. This circular area adjoins the preferably cylindrical shaft directly or directly. The longitudinal axis represents the central axis around which the circular area is rotated through 360 °. The circular area is thus mirror-symmetrical in cross section along the longitudinal axis with respect to the longitudinal axis.

The center point of the circular area is arranged on the vertical on the side opposite the circular area in relation to the longitudinal axis. Thus, a distance between the circular area and the longitudinal axis of the shaft is reduced in the direction of the convex circular end area, which is illustrated in particular on the basis of the figures discussed later.

The ogival shape is truncated spherically at the second end due to the circular end region, which is convex in cross section along the longitudinal axis and adjoins the ogival region directly or directly. This configuration is therefore also referred to as a spherical or spherically truncated ogival shape. A transition between the ogival area and the spherical shape is preferably stepless. Alternatively, a transition using a step is also preferred.

Due to the features according to the invention, ie the spherically truncated ogival shape in connection with the ratio between the radius n of the circular area and the diameter d _{S of} the shaft between 0.6 and 5.5, the tip of the joining element is geometrically adapted to maximize dimensional stability and at the same time to ensure a selective application of force. Due to this special geometric adaptation, the risk of breaking the joining element, deformation of the tip and severing of a slug in the case of a translational setting, i.e. in the case of essentially rotation-free setting, of the joining element in the components to be connected and not pre-punched in the joining area is compared reduced to the known joining elements or preferably eliminated.

In particular, the more robust tip of the joining element formed in this way avoids plastic deformation of the joining element due to mechanical stresses in the joining process. This also and especially applies with regard to the use of a high-strength or ultra-high-strength steel for one of the components to be connected to one another, in particular for the lower, ie head-off applied, component with a translational setting of the joining element in a non-prepunched joining area, whereby the tip of the joining element penetrates the component.

In the context of the invention, it was found in this regard that the process-reliable penetration of the components to be connected with the tip of the joining element, especially if one of the components to be connected consists of high-strength or ultra-high-strength steel, as well as the formation of slugs are decisive depend on the diameter of the shaft and the radius r ₁ of the area which is circular in cross section along the longitudinal axis, ie the ogival shape. In order to avoid deformation of the tip of the joining element and thus counteract the formation of slugs, the joining force acting on the pin tip must be distributed over the largest possible cross-sectional area so that the stresses remain well below the yield point of the material of the joining element.

At the same time, the bolt tip must transfer the joining force selectively to the component made of high-strength or ultra-high-strength steel facing away from the head in order to cut through the component at the point of attack and then expand it fluently. Otherwise the shear strength of the high-strength or ultra-high-strength steel is exceeded and a slug is suddenly punched out. The latter is observed in particular when using a joining element with one of the known geometries.

In a preferred embodiment of the joining element, the following applies to the ratio between the first radius r ₁ and the diameter d _{S of} the shaft adjacent to the tip: 0.8 r ₁ / d _S 5.0, preferably 0.9 r ₁ / d _S 4.5 and particularly preferably 0.9 r ₁ / d _S 2.0. The optimum for the translational setting of the joining element, ie the essentially rotation-free setting, is described by the ratio between the radius r _{1 of} the circular area and the diameter of the shaft. In the context of the present invention, this ratio is also referred to as the equivalence quotient or the equivalence factor.

The range of values between 0.9 and 2.0 has proven to be particularly advantageous here, since this range of values provides a geometrically sharp point in relation to the shaft diameter, which diverges strongly in the direction of the head of the joining element. In this way, the risk of plastic deformation of the tip and the severing of a slug are further reduced if the joining element is only set translationally into the components that are not prepunched in the joining area, the tip of the joining element penetrating the components. A value range of 0.9 to 1.3 is particularly advantageous for the equivalence factor, which _{results in a first radius r 1} of approximately 3 mm to approximately 4 mm for an exemplary shaft diameter of 3.15 mm. The advantage compared to larger radii of> 6mm, ie an equivalence factor over 2, is that the cross-sectional area increases faster in the direction of the head and the reaction forces are thus distributed over a larger area. As a result, the resulting stress is preferably still below the yield point of the material of the joining element, so that the tip is not deformed.

In a further preferred embodiment of the joining element, the following applies to the second radius r ₂ : r ₂ 0.4 d _S , in particular r ₂ 0.3 d _S and particularly preferably r ₂ 0.2 d _S. It is precisely this tip radius that anticipates deformation of the tip and thus limits possible joining energy losses to a minimum.

A further advantage of this second radius r ₂ results in particular in combination with the diameter d _{S of} the shaft and the first radius r ₁ , that is to say the equivalence quotient. The resulting technical effect is the geometric resistance to deformation, the radius r ₂ in relation to the shaft diameter still being pointed enough to be able to penetrate the components to be connected, in particular the component facing away from the head, without separating a slug. The tip radius r _{2 is} particularly preferably in the range from 0.1 to 0.6 mm.

It is also preferred that for a ratio between the first radius r ₁ and the second radius r _{2 the} following applies: r ₁ / r ₂ 4.0, preferably r ₁ / r ₂ 4.5 and particularly preferably r ₁ / r ₂ 10, and / or r ₁ / r ₂ 100, preferably r ₁ / r ₂ 50 and particularly preferably r ₁ / r ₂ 40. This further reduces the risk of plastic deformation of the tip.

In an advantageous embodiment of the joining element, the following applies for a length 1 _{S of} the shaft: 1 _S

5 mm. Depending on the thickness of the components to be connected to one another, reliable connection of the components to one another is no longer guaranteed if this value is not reached. In particular, the preferred length 1 _S of at least 5 mm ensures that a force fit or form fit is guaranteed even with thicker components. One advantage is that with the joining element designed in this way, the process-reliable joining of a high-strength or ultra-high-strength steel, for example a press-hard 22MnB5 profile, which has a high tensile strength of more than 1,400 MPa, is made possible in particular as a component facing away from the head. With this preferred embodiment of the joining element, the process-reliable joining is also given with this material with a material thickness of more than 1.3 mm and with only one-sided accessibility of the components to be connected to one another.

In a particularly preferred embodiment of the joining element, the vertical is arranged between the shaft and the tip, so that a tangent ogi ve results. In the case of the tangent ogive, the circular area is arranged tangentially to the preferably cylindrical shaft. An advantage of this embodiment results in comparison to the use of a secant ogive in which the area, which is circular in cross section along the longitudinal axis, is not arranged tangentially to the shaft, but intersects it at an acute angle. In the case of the edging ogive, the components to be connected to one another are widened to a greater extent, which can result in disadvantages when fastening the joining element in the components to be connected to one another. The use of a tangent ogive is therefore preferred.

The head of the joining element advantageously has a cylindrical circumferential surface and a flat underside, with an annular groove being present in the flat underside adjacent to the shaft for receiving a bulge-shaped material bulge of the head-side component. It is also preferred that the annular groove adjacent to the shaft has a rounded circumferential surface which merges tangentially into the shaft on the one hand and into a conical surface on the other. In this way, especially when the upper material rises against the joining direction with a corresponding material-thickness combination, it can be received in the annular groove.

In a further preferred embodiment of the joining element, the shaft comprises a

Surface profiling for receiving material from the component facing away from the head. In this way, the joining element is fastened particularly reliably in the component facing away from the head, which consists of the high-strength or ultra-high-strength steel.

A connection structure according to the invention consists of at least a first component and a second component, which are connected by means of a joining element according to the invention. With regard to the resulting advantages and technical effects, reference is therefore made to the above statements on the joining element according to the invention in order to avoid unnecessary repetitions. In a preferred embodiment of the connection structure, the first component is arranged adjacent to the head and the second component is arranged adjacent to the tip of the joining element, the second component being made of steel, in particular hot-formed steel, with a tensile strength of at least 1,400 MPa. The head remote or lower component thus consists of a high-strength or ultra-high-strength steel, in particular a press-hard steel such as Usibor. Due to the specific geometry of the tip of the joining element, when the joining element is placed in such a component and when it penetrates the component, the risk of plastic deformation of the tip and breakage of the joining element is reduced or preferably eliminated. In addition, the joining element designed in this way prevents a slug from being separated from the second steel component with a tensile strength of at least 1,400 MPa.

A method according to the invention for connecting at least one first component to a second component by means of a joining element according to the invention comprises the steps: arranging the first and the second component one above the other, placing the joining element in the arrangement of the first and second component arranged one above the other, with the setting of the joining element - ments is essentially rotation-free. The essentially rotation-free setting can also be referred to as exclusively translatory setting of the joining element. This setting takes place in the components that are not prepunched in the joining area and are to be connected to one another. At the end of the setting process, the tip of the joining element has penetrated both components. With regard to the resulting advantages, reference is made to the above statements on the joining element according to the invention in order to avoid repetitions.

In a preferred embodiment of the method, the first component is arranged adjacent to the head and the second component is arranged adjacent to the tip of the joining element, the second component being made of a steel, in particular a hot-formed steel, with a tensile strength of at least 1,400 MPa. As explained above in connection with a preferred embodiment of the connection structure, the head-facing or lower component thus consists of a high-strength or ultra-high-strength steel, in particular a press-hard steel such as Usibor. Due to the specific geometry of the tip of the joining element, when the joining element is placed in such a component and when penetrating the component, the risk of plastic deformation of the tip and breakage of the joining element of the joining element is reduced or preferably eliminated. In an advantageous embodiment of the method, the first component is arranged adjacent to the head and the second component is arranged adjacent to the tip of the joining element, the second component penetrating without severing a slug. It is precisely the specific geometry of the joining element according to the invention that makes it possible that no slug is cut off from the second component made of steel with a tensile strength of at least 1,400 MPa. Rather, the component is severed at the point of attack and then widened smoothly, which will be clarified later with reference to the figures.

4. Brief summary of the drawings

In the following, the present invention will be described in detail with reference to the drawings. The same reference symbols in the drawings denote the same components and / or elements. Show it:

FIG. 1a shows a cross-sectional view of a joining element set in two components,

FIG. 1b shows a perspective view of the arrangement according to FIG. 1a with the tip of the joining element,

Figure 2 is a schematic drawing to illustrate an ogival shape,

FIG. 3 shows a side view with a partial cross section of a joining element to illustrate a spherically truncated ogival shape,

FIG. 4a shows a side view with a partial cross section of a joining element,

FIG. 4b shows an enlarged view of the circled tip area from FIG. 4a,

FIG. 5a shows a side view with a partial cross section of a first embodiment of a joining element according to the invention,

FIG. 5b shows an enlarged view of the circled tip area from FIG. 5a, FIG. 6 shows a side view with a partial cross section of a second embodiment of a joining element according to the invention,

FIG. 7 shows a side view with a partial cross section of a third embodiment of a joining element according to the invention,

FIG. 8a shows a side view with a partial cross section of a fourth embodiment of a joining element according to the invention,

FIG. 8b shows an enlarged view of the circled tip area from FIG. 8a,

FIG. 9 shows a side view with a partial cross section of a fifth embodiment of a joining element according to the invention,

FIG. 10a shows a side view with a partial cross section of a sixth embodiment of a joining element according to the invention,

FIG. 10b shows an enlarged view of the circled tip area from FIG. 10a,

FIG. 11a shows a side view with a partial cross section of a seventh embodiment of a joining element according to the invention,

FIG. 11b shows an enlarged view of the circled tip area from FIG. 11a,

FIG. 12a shows a cross-sectional view of a joining element set in two components according to an embodiment of the invention,

FIG. 12b shows a perspective view of the arrangement according to FIG. 12a with the tip of the joining element and

FIG. 13 shows a flow diagram of an embodiment of a method for connecting two components. 5. Detailed Description of the Preferred Embodiments

Referring to FIG. 1 a, a cross-sectional view of a connecting structure is shown, which consists of a first component A and a second component B, which are connected to one another by means of a joining element 1. The second component B consists of a high-strength or ultra-high-strength steel that has a high tensile strength of more than 1,400 MPa, for example Usibor. Before the joining element was set, both components were not prepunched in the joining area.

In a known manner, the joining element 1 has a head 10 at a first axial end, a tip 20 at a second axial end and a shaft 30 arranged in between. The tip 20 has, adjacent to the shaft 30, a circular region 22 with a first radius r ₁ , which will be explained later. Due to a translational setting process in which the originally ogival tip of the joining element 1 has penetrated both components A, B that were not prepunched in the joining area, the tip was plastically deformed in the end area 26. This is particularly disadvantageous with regard to the energy required to place the joining element 1 in the two components A, B.

FIG. 1b shows a perspective view of the arrangement from FIG. La from the second component B. This figure shows another disadvantage when using a high-strength or extremely high-strength steel as the second component B in connection with the joining element 1. Thus, the use of the joining element 1 not only leads to the tip being plastically deformed in the end region 26, but also a slug 40 is cut out of the second component B. This is disadvantageous especially when the components A, B to be connected are only accessible from one side.

The fundamentals for the geometry of the tip 20 are explained on the basis of FIG. 2, which shows a schematic representation of a shaft 30 and a tip 20 of a joining element in order to illustrate the creation of an ogival body.

An ogival body or area is usually defined by an arc of a circle, i.e. the one in the

Cross section along the longitudinal axis of the circular region 22 with the first radius r ₁ , which is rotated through 360 ° around the longitudinal axis L. If such an ogival region is viewed in cross section along the longitudinal axis L, as shown in FIG. 2, the circular one is located Area 22 mirror-symmetrically to the longitudinal axis L in front. An ogival shape is therefore a body of revolution.

As can also be seen from FIG. 2, the circular area 22 adjoins the preferably cylindrical shaft 30 directly or directly.

A center point M of the circular region 22 is arranged on a perpendicular S to the longitudinal axis L. The center point M for the circular area 22 above the longitudinal axis L is shown in FIG. Since the circular area 22 for producing the ogival shape is designed mirror-symmetrically to the longitudinal axis L, the circular area 22 extends at most from the shaft 30 to the point at which it intersects the longitudinal axis L.

Due to the resulting ogival shape of the tip 20 in this area, a distance between the circular area 22 and the longitudinal axis L from the shaft 30 in the direction of the second axial end of the joining element is reduced. As can also be seen from this, the center point M of the circular area 22 is arranged on the side opposite the circular area 22 in relation to the longitudinal axis L. Therefore, the center point M for the circular area 22 below the longitudinal axis L is correspondingly on the perpendicular S above the longitudinal axis L.

Depending on the ratio between the radius r ₁ and the diameter d _{S of} the shaft 30, which is cylindrical here, adjacent to the tip 20, there are different configurations for the ogival shape. The dotted line in FIG. 2 shows a semicircular tip 20. This configuration is the result when the following applies to the ratio between the radius r ₁ and the diameter d _{S of} the shaft 30: r ₁ / d _S = 0 , 5. In the context of the present invention, this ratio is also referred to as the equivalence factor or equivalence quotient. An equivalence factor of 1.0 therefore means that the first radius r ₁ and the diameter d _{S of} the shaft 30 are of the same size, which results in the ogival shape adjacent to the dotted line. An ogival factor of approximately 2.0 results in the outermost ogival shape for which the first radius r _{1 is} drawn. The mean ogival shape is therefore obtained with an ogivality factor of approximately 1.5.

With regard to the transition between the shaft 30 and the ogival shape or the circular area 22 with the first radius r ₁ , a tangent ogive and a secant Ogive distinguished. In the case of the tangent ogive, the shaft 30 merges tangentially into the circular area 22. In this case, the perpendicular S to the longitudinal axis L is arranged exactly between the shaft 30 and the tip 20. The secant ogive differs from the tangent ogive in that the circular area 22 is not arranged tangentially to the shaft 30, but intersects it at an acute angle. The vertical S is therefore arranged, for example, in the area of the shaft 30, that is to say further offset in the direction of the first axial end.

Referring now to FIG. 3, a modification of the ogival shape of the tip of a joining element is explained. The joining element shown here has a head 10 with an upper side 12 and an underside 14, a shaft 30 and a tip 20. The head diameter is marked with d _K , the total length of the joining element with l _G and the diameter of the shaft 30 with d _S.

The enlarged section shows that the tip 20 consists of two areas. In a first region, the tip 20 has the region 22, which is circular in cross section along the longitudinal axis and has the first radius r ₁ . In this area, the tip 20 is thus formed ogivally. This ogival area is followed by a circular end area 24 with a convex cross section along the longitudinal axis L and a second radius r ₂ . In this way, the ogival shape of the first area is truncated by means of a spherical shape. So it is a spherical truncated ogival shape.

To illustrate the importance of the tip geometry in joining elements, FIGS. 4a and 4b show a joining element with a spherically truncated ogival shape of the tip 20. In a known manner, the joining element 1 comprises the head 10, the tip 20 and the shaft 30. The head 10 has an annular groove 16 and the shaft 30 via a surface profile 32.

The tip 20 consists of the circular area 22 and the convex circular end area 24. The configuration shown here has a ratio between the first radius r _{1 of} the circular area 22 and the diameter d _{S of} the shaft of approximately 8.2. With an exemplary diameter d _S of 3.05 mm, a first radius r ₁ of 25 mm therefore results. FIG. 4b shows an enlargement of the circled area from FIG. 4a. The second radius r _{2 of} the convex, circular end region 24 is of the order of magnitude of approximately 0.32 d _S , ie, based on the above example, approximately 1.0 mm.

If a joining element designed in this way is used to establish a connection between two components, the risk of plastic deformation of the tip 20 can be at least partially reduced compared to using a joining element with an equivalence factor above 10, so that avoiding the plastic deformation is not feasible. This is particularly true if the component facing away from the head is made of high-strength or ultra-high-strength steel. In addition, the disadvantage remains that a slug is cut off. This is particularly disadvantageous when the components to be connected are assumed to be only accessible from one side and should therefore be avoided.

Embodiments of the joining element according to the invention are described below with reference to FIGS. 5a to 11b, with FIGS. 12a and 12b showing the joining element in a connection structure. All of these embodiments have an equivalence factor between 0.6 and 5.5, as a result of which both a plastic deformation of the tip 20 and the separation of a slug when it is placed in high-strength or ultra-high-strength steel is prevented or avoided.

First, the first embodiment according to FIGS. 5a and 5b will be described. With regard to the further embodiments, the differences will then mainly be discussed in order to avoid repetition.

According to the first embodiment of the joining element 100, the joining element 100 comprises a head 10 at a first axial end, a tip 20 at a second axial end opposite the first axial end and a shaft 30 arranged between the tip 20 and the head 10 Shank 30 defines a longitudinal axis L of joining element 100 between the first and second axial ends.

The head 10 of the joining element 100 has a flat top side 12, a cylindrical circumferential surface and a flat bottom side 14. In the flat underside 14 there is an annular groove 16 adjacent to the shaft 30 for receiving a bulge-shaped material bulge of the component A on the head side. The annular groove 16 has a rounded one adjacent to the shaft 30 circumferential surface which merges tangentially on the one hand into the shaft 30 and on the other hand into a conical surface. In this way, when the upper material rises against the joining direction with a corresponding material-thickness combination, it can be received in the annular groove 16.

The shaft 30 is cylindrical and comprises, at least in a partial area, a surface profile 32 for receiving material from the component B facing away from the head. In this way, the joining element 100 is fastened particularly reliably in the components A, B to be connected. A length 1 _{S of} the shaft 30 (see FIG. 6) is at least 5 mm. The reason for this is that the length ls of at least 5 mm in particular ensures that a force fit or form fit between the components and the joining element 100 is guaranteed even when thicker components are connected. One advantage is that the joining element 100 designed in this way enables the process-reliable joining of high-strength or ultra-high-strength steel, for example a press-hard 22MnB5 profile that has a high tensile strength of more than 1,400 MPa, in particular as component B facing away from the head. With the embodiment of the joining element, the process-reliable joining is also given with this material with a material thickness of more than 1.3 mm and with only one-sided accessibility of the components to be connected to one another.

The tip 20 with the circular area 22 and the convex circular end area 24 adjoins the shaft 30 directly. In the illustrated embodiments of the joining element according to the invention, the perpendicular S is arranged between the shaft 30 and the tip 20, so that a tangent ogive results. An advantage of this embodiment results in comparison to the use of a secant ogive. This is because the components to be connected to one another are widened to a greater extent with the countersunk ogive, which can result in disadvantages when fastening the joining element in the components A, B that are to be connected to one another and are not pre-punched in the joint area.

In cross section along the longitudinal axis L, the tip 20 has the circular region 22, which is mirror-symmetrical with respect to the longitudinal axis L and has the first radius r _1, adjacent to the shaft 30. As explained with reference to FIG. 2, the center M of the circular area 22 lies on a perpendicular to the longitudinal axis L of the joining element 100, so that the tip in the circular area 22 tapers to the second axial end in an ogival shape. The Ogivali- The efficiency factor of the first embodiment is approximately 5.25, which corresponds to _{a first radius r 1} of approximately 16.0 mm _{for a diameter d S of} the shaft 30 of 3.05 mm.

Furthermore, the tip 20 has the circular end region 24, which is convex in cross section along the longitudinal axis, with the second radius r ₂ following the circular region 22. The center point of the convex circular end region 24 is arranged on the longitudinal axis L of the joining element 100 adjacent to the second axial end. In this embodiment, the following applies to the second radius r ₂ _{: r 2} = 0.16 d _S , which, given an exemplary diameter of 3.05 mm, leads to a second radius r ₂ of approximately 0.5 mm. A ratio of the first radius r ₁ to the second radius r ₂ is thus: r ₁ / r ₂ = 32. A diameter d _{E of} the end region 24 at the border with the circular region 22 is, for example, 0.6 mm. A transition between the circular area and the end area is preferably stepless. Alternatively, a transition using a step is preferred at this point.

Due to this specific design, ie the spherically truncated ogival shape in connection with the ratio between the radius r _{1 of} the circular area 22 and the diameter d _{S of} the shaft 30 between 0.6 and 5.5, the tip 20 of the joining element 100 is geometrically adapted in order to ensure the greatest possible dimensional stability and, at the same time, a selective application of force. As a result, the risk of fracture of joining element 100, deformation of tip 20 and severing of a slug in the event of a translational setting, ie in the case of an essentially rotation-free setting, of the joining element 100 in the components A, B to be connected is compared to the known joining elements reduced.

In particular, the more robust tip 20 of the joining element 100 formed in this way avoids plastic deformation of the joining element 100 due to mechanical stresses in the joining process. This also and especially applies with regard to the use of high-strength or ultra-high-strength steel for one of the components A, B to be connected to one another, in particular for the lower component B, that is, component B facing away from the head. B, especially if one of the components A, B to be connected to one another is made of high-strength or ultra-high-strength steel, and the formation of slugs depends largely on the diameter d _{S of} the shaft 30 and the first radius r _{1 of} the circular area 22, ie the ogival shape . In order to avoid deformation of the tip 20 of the joining element 100 and thus counteract the formation of slugs, the joining force acting on the tip 20 must be distributed over the largest possible cross-sectional area so that the stresses are well below the yield point of the material of the joining element 100 stay. In addition, the tip 20 must transfer the joining force selectively to the component B facing away from the head, made of high-strength or ultra-high-strength steel, in order to cut through the component B at the point of application and then to expand it fluently. Otherwise the shear strength of the high-strength or ultra-high-strength steel is exceeded and a slug is suddenly punched out.

Referring now to FIG. 6, a second embodiment of a joining element 200 is shown. As explained above, the basic structure corresponds to the structure of the first embodiment of the joining element 100. In contrast to the joining element 100, the shaft 30 is made longer and the surface profile 32 therefore extends over a longer area. However, the surface profile ends at a distance from the tip 20, so that a region of the shaft 30 adjacent to the tip 20 is free of the surface profile 32.

In the context of the second embodiment of the joining element 200, the equivalence factor was further reduced to a value of approx. 4.26. With the exemplary diameter d _{S of} the shaft 30 of 3.05 mm, this corresponds to a first radius r ₁ of approx. 13.0 mm. In this embodiment, the following applies to the second radius r ₂ _{: r 2} = 0.33 d _S , which equates to a second radius r ₂ of 1.0 mm. The ratio of the first radius h to the second radius r ₂ is thus: r ₁ / r ₂ =

13. The change in the ratios is also clear when comparing the first embodiment with the second embodiment. Thus, the first embodiment has a significantly longer stretched tip 20 due to the higher equivalence factor. The end region 24 is also designed to be more pointed in the first embodiment.

In the third embodiment of the joining element 300 according to FIG. 7, the greater length of the shaft 30 was retained and the equivalence factor was also kept at a value of approximately 4.26. This results in a first radius r ₁ of approximately 13.0 mm for the exemplary diameter d _{S of} the shaft 30. For the second radius r ₂ , however, in this embodiment: r ₂ = 0.16 d _S , which is a halving and thus equals a second radius r ₂ of 0.5 mm. The ratio of the first radius r ₁ to the second radius r ₂ has thus doubled and is: r ₁ / r ₂ = 26. The change in the ratios is also clear when comparing the second embodiment with the third embodiment. So has the third embodiment due to the smaller second radius r _2, a significantly longer pointed tip 20, since the convex circular end region 24 starts closer to the second axial end. In addition, the end region 24 is designed to be more pointed in the third embodiment.

In the context of the fourth embodiment of the joining element 400 according to FIGS. 8a and 8b, the shaft 30 was shortened in comparison to the second and third embodiment, the equivalence factor being further reduced to a value of approximately 1.97. The shaft 30 is also provided with a surface profile 32 directly adjacent to the tip 20. With the exemplary diameter d _{S of} the shaft 30 of 3.05 mm, the equivalence factor corresponds to a first radius r ₁ of approximately 6.0 mm. In this embodiment, the following applies to the second radius r ₂ _{: r 2} = 0.05 d _S , which equates to a second radius r ₂ of 0.15 mm. The ratio of the first radius r ₁ to the second radius r ₂ is thus: r ₁ / r ₂ = 40. A diameter d _{E of} the end region 24 at the border with the circular region 22 is, for example, 0.5 mm, which results in a slight constriction on the The transition between the end area 24 and the circular area 22 results. As explained above, such a transition is also preferred in addition to a direct or stepless transition. As a result, the tip 20 of the fourth embodiment is therefore less elongated than in the third embodiment. In addition, the end region 24 is designed to be more pointed in the fourth embodiment.

In the fifth embodiment of the joining element 500 according to FIG. 9, the length of the shaft 30 was increased again and the equivalence factor was further reduced to a value of approximately 1.31. The shaft 30 again has, adjacent to the tip 20, a region that is free of the surface profiling 32. The equivalence factor here results in a first radius r ₁ of approximately 4.0 mm for the exemplary diameter d _{S of} the shaft 30, for the second radius r ₂ applies in this embodiment: r ₂ = 0.05 d _S , which equals a second radius r ₂ of 0.15 mm. The ratio of the first radius r ₁ to the second radius r ₂ is: r ₁ / r ₂ = 26.7. Thus, the second radius is the same in the fourth and fifth embodiments, but the first radius has been further reduced in the fifth embodiment. This has an advantageous effect on the behavior of the joining element 500 when it penetrates the components A, B to be connected to one another.

The sixth embodiment of the joining element 600 according to FIGS. 10a and 10b essentially corresponds to the fifth embodiment, but the shaft 30 has been shortened compared to the fifth embodiment. This configuration thus also has an equivalence factor from approx. 1.31 to. With the exemplary diameter d _{S of} the shaft 30 of 3.05 mm, the equivalence factor corresponds to a first radius r ₁ of approximately 4.0 mm, as in the fifth embodiment. The _{same applies to the second radius r 2} as in the fifth Embodiment: r ₂ = 0.05 d _S , which corresponds to a second radius r ₂ of 0.15 mm. The ratio of the first radius r ₁ to the second radius r ₂ is thus: r ₁ / r ₂ = 26.7.

In the seventh embodiment of the joining element 700 according to FIGS. 11a and 11b, the length of the shaft 30 was retained in comparison to the sixth embodiment, as was the value of the equivalence factor of approximately 1.31. The shaft 30 has, adjacent to the tip 20, a region that is free of the surface profiling 32. The equivalence factor also results here in a first radius r ₁ of approximately 4.0 mm for the exemplary diameter d _{S of} the shaft 30. For the In this embodiment, however, the following applies to the second radius r ₂ _{: r 2} = 0.16 d _S , which equates to a second radius r ₂ of 0.5 mm. The ratio of the first radius r ₁ to the second radius r ₂ is: r ₁ / r ₂ = 8.0. As a result, the end region 24 is designed to be flatter in comparison to the sixth embodiment, which further advantageously supports the penetration of the components A, B to be connected to one another.

Figures 12a and 12b show an embodiment of a connection structure according to the invention consisting of a first component A facing the head and a second component B facing away from the head, which are connected by means of an embodiment of the joining element according to the invention, for example the joining element again 700.

The second component B consists of a steel, in particular a hot-formed steel, with a tensile strength of at least 1,400 MPa. The lower component B facing away from the head was thus produced from a high-strength or ultra-high-strength steel, in particular a press-hard steel such as Usibor, for example. Due to the specific geometry of the tip of the joining element 700, when the joining element 700 is placed in such a component B and when the component B penetrates, the risk of plastic deformation of the tip 20 and fracture of the joining element 700 is reduced or preferably eliminated. In addition, the joining element 700 designed in this way prevents a slug from being separated from the second component made of steel with a tensile strength of at least 1,400 MPa. Rather, the material of the second component B is severed at the point of application and then widened in a flowing manner at the point at which the tip 20 emerges from the second component B. Finally and with reference to FIG. 13, a flowchart of an embodiment of a method for connecting a first component A to a second component B by means of an embodiment of a joining element is shown. In a first step A, the first A and the second component B are arranged one above the other. In a subsequent second step, the joining element is placed in the arrangement of the first and second component arranged one above the other, the joining element being placed essentially without rotation. The essentially rotation-free setting can also be referred to as exclusively translatory setting of the joining element.

The first component is arranged adjacent to the head and the second component adjacent to the tip of the joining element when it is set, and both components are not prepunched in the joining area, as already discussed. The second component consists in particular of a steel, preferably a hot-formed steel, with a tensile strength of at least 1,400 MPa. A penetration of the second component B takes place without separation of a slug. It is precisely the specific geometry of the joining element according to the invention that makes it possible that no slug is separated from the second component made of steel with a tensile strength of at least 1,400 MPa. Rather, the material of the second component is cut through and then expanded in a flowing manner (see FIG. 12b).

6. List of Reference Numbers

1 joining element 10 head 12 top 14 bottom 16 annular groove

20 tip

22 circular area 24 convex circular end area 26 plastically deformed end area

30 shaft 32 Surface profiling

40 slugs 100 first embodiment of a joining element

200 second embodiment of a joining element 300 third embodiment of a joining element 400 fourth embodiment of a joining element 500 fifth embodiment of a joining element 600 sixth embodiment of a joining element

700 seventh embodiment of a joining element d _E diameter of the convex circular end area d _K diameter of the head d _S diameter of the shank h _K height of the head l _G total length of the joining element l _S length of the shank r ₁ radius of the circular area r ₂ radius of the convex circular end area

A first component B second component L longitudinal axis M center

S vertical

Claims

1. A joining element for establishing a connection between at least two components, in particular a setting bolt, which has: a. a head at a first axial end, b. a tip at a second axial end opposite the first axial end, and c. a shaft arranged between the tip and the head and defining a longitudinal axis of the joining element between the first and second axial ends, where d1. the tip in cross-section along the longitudinal axis has a circular area mirror-symmetrical with respect to the longitudinal axis with a first radius r ₁ adjacent to the shaft, the center of which lies on a perpendicular to the longitudinal axis of the joining element, so that the tip in the circular area is ogive to the second axial The end is running out, and d2. the tip has a convex circular end region with a second radius r ₂ following the circular region, the center point of which is arranged on the longitudinal axis of the joining element adjacent to the second axial end, where d3. for a ratio between the first radius n and a diameter d _{S of} the shaft adjacent to the tip, the following applies:

0.6 ≤ r ₁ / d _S ≤ 5.5,

2. The joining element according to one of the preceding claims, in which the following applies to the ratio between the first radius r ₁ and the diameter d _{S of} the shaft adjacent to the tip: 0.8 ≤ r ₁ / d _S ≤ 5.0, preferably 0, 9 r ₁ / d _S 4.5 and particularly preferably 0.9 r ₁ / d _S 2.0.

3. The joining element according to one of the preceding claims, in which the following applies to the second radius r ₂ : r ₂ 0.4 d _S , in particular r ₂ 0.3 d _S and particularly preferably r ₂ 0.2 d _S.

4. The joining element according to one of the preceding claims, in which the following applies to a ratio between the first radius r ₁ and the second radius r ₂ : r ₁ / r ₂ ≥ 4.0, preferably r ₁ / r ₂ 4.5 and particularly preferably r ₁ / r ₂ 10, and / or r ₁ / r ₂ 100, preferably r ₁ / r ₂ 50 and particularly preferably r ₁ / r ₂ 40 .

5. The joining element according to one of the preceding claims, in which the following applies to a length 1 _{S of} the shaft: ls ≥ 5 mm.

6. The joining element according to one of the preceding claims, in which the perpendicular is arranged between the shaft and the tip, so that a tangent ogive results.

7. The joining element according to one of the preceding claims, in which the shaft is cylindrical.

8. The joining element according to one of the preceding claims, in which the head has a cylindrical circumferential surface and a flat underside, with an annular groove adjacent to the shaft for receiving a bulge-shaped material bulge of the head-side component in the flat underside.

9. The joining element according to claim 8, wherein the annular groove adjacent to the shaft has a rounded circumferential surface which merges tangentially on the one hand into the shaft and on the other hand into a conical surface.

10. The joining element according to one of the preceding claims, in which the shaft comprises a surface profile for receiving material of the component facing away from the head.

11. A connection structure consisting of at least a first component and a second component, which are connected by means of a joining element according to one of the preceding claims.

12. The connection structure according to claim 11, in which the first component is arranged adjacent to the head and the second component is arranged adjacent to the tip of the joining element, the second component being made of a steel, in particular a hot-formed steel, with a tensile strength of at least 1,400 MPa.

13. A method for connecting at least one first component to a second component by means of a joining element according to one of the claims 1 to 12, comprising the steps: a. Arranging the first and the second component one above the other, b, placing the joining element in the arrangement of the first and second component arranged one above the other, the joining element being placed essentially rotation-free.

14. The method according to claim 13, in which the first component is arranged adjacent to the head and the second component is arranged adjacent to the tip of the joining element, the second component being made of a steel, in particular a hot-formed steel, with a tensile strength of at least 1,400 MPa consists.

15. The method according to claim 13 or 14, wherein the first component is adjacent to

The head and the second component are arranged adjacent to the tip of the joining element, the second component being penetrated without severing a punched socket.