Connecting element, assembly, and method

Abstract

The invention relates to a connecting element (10) for inserting into a through-opening (22) in a component (20), wherein the through-opening (22) has at least one widened portion (26), the connecting element (10) has an annular expansion collar (16) which protrudes from the lower face of the connecting element (10), and the expansion collar (16) is designed such that it can be expanded in the radial direction by way of plastic deformation.

Description

[0001] Fastener, arrangement and method

[0002] The invention relates to a connecting element for insertion into a through-opening of a component. The invention also relates to an assembly comprising a connecting element. The invention further relates to a method for producing a through-opening in a component and a method for inserting a connecting element into a through-opening of a component.

[0003] The invention is intended to improve a connecting element, an arrangement comprising a connecting element, a method for producing a through-opening in a component and a method for inserting a connecting element into a through-opening of a component.

[0004] According to the invention, a connecting element having the features of claim 1, an arrangement having the features of claim 5, a method for producing a through-opening in a component having the features of claim 12, and a method for inserting a connecting element into a through-opening of a component having the features of claim 17 are provided. Advantageous developments of the invention are specified in the respective subclaims.

[0005] A connecting element for insertion into a through-hole of a component, wherein the through-hole has at least one widening section, has an annular expansion collar protruding from an underside of the connecting element, wherein the expansion collar is designed such that it can be expanded in the radial direction by means of plastic deformation. By simply expanding the expansion collar, the connecting element can be securely anchored in the through-hole. For example, electrical connection points, welding points, and generally connecting elements, can be anchored to a component in this way. A very significant advantage of the connecting element according to the invention is that the preparation of the through-hole in the component can be accomplished quickly and easily.To securely anchor the connecting element with the annular expansion collar, a through-hole with at least one widening section is sufficient. The widening section advantageously extends to the end of the through-hole, so that the end of the widening section with a large diameter also forms the end of the through-hole. In particular, no beads, depressions, or other indentations surrounding a through-hole are required in the component, as is necessary, for example, when setting rivets or the like if the underside of the connecting element is to be flush with the underside of the component. The expansion collar is only slightly deformed, so that the deformation forces can be kept low, and the material stress on the connecting element in the area of ​​the deformed expansion collar can also be kept low.The component itself has the through-opening that widens at least in sections and does not need to be formed. As a result, the connecting element according to the invention can also be used in components made of a material of comparable strength to the connecting element itself. As a rule, one joining partner must be harder than the other, but this is not the case with the invention. If, for example, rivets are inserted into a component, the component must always be made of a harder material to enable clean formation of the rivet without excessively deforming the component itself. The connecting element according to the invention is inserted into an expanding section of the through-opening by means of plastic deformation of the expanding collar. The component itself is not deformed in the process.The component and the connecting element can therefore be made of the same material or of different materials, with the material of the component being harder or softer than the material of the connecting element. The connecting element according to the invention can thus be used in an extremely flexible manner.

[0006] In a further development of the invention, an outer contour of the expansion collar, seen in cross section, is circular, elliptical, polygonal, in particular hexagonal, or polygonal with rounded corners.

[0007] In a further development of the invention, an inner contour of the expansion collar is, seen in cross section, circular, elliptical, polygonal, in particular hexagonal, or polygonal with rounded corners.

[0008] In a further development of the invention, the connecting element consists of a plastically deformable metallic material, in particular aluminum, at least in the area of ​​the expansion collar.

[0009] The wall thickness of the annular expansion collar can be constant; however, according to the invention, this is not necessarily the case. In this way, the connecting element can be manufactured in a simple manner, for example by cold forming. In particular, the annular expansion collar has a rectangular cross-section in a sectional plane containing the central longitudinal axis of the expansion collar. Viewed in a direction parallel to a central longitudinal axis of the expansion collar, the expansion collar can be circular. If additional security against twisting of the connecting element in the through-opening is required, the circumference of the expansion collar can also deviate from a circular shape, for example, be elliptical, rectangular, in the shape of a regular polygon, or similar.

[0010] An arrangement according to the invention with a connecting element and at least one component connected to the connecting element is characterized in that the connecting element has an annular expansion collar projecting from a bottom side of the connecting element and in that the component has a through-opening, wherein the through-opening has at least one widening section, wherein the expansion collar of the connecting element extends into the through-opening and at least partially bears against an inner wall of the widening section of the through-opening.

[0011] By simply expanding the expansion collar and allowing it to undergo plastic deformation during expansion until it partially rests against an inner wall of the expanding section of the through-hole, the connecting element can be securely anchored to the component. The component does not require any complex preparation for this; only a through-hole with an expanding section is required. In particular, no beads, recesses, or protrusions are required on the component to securely anchor the connecting element.

[0012] In a further development of the invention, the through-opening has a first, cylindrical section, wherein the widening section adjoins the first section.

[0013] The widening section forms an undercut to which the expansion collar can be anchored. By providing the first, cylindrical section, even very thick components, such as thick sheet metal, can be easily provided with a through-hole, allowing the secure anchoring of the fastener using the expansion collar.

[0014] In a further development of the invention, the widening section is truncated cone-shaped or truncated pyramid-shaped. In a further development of the invention, the widening section, viewed in cross-section, is circular, elliptical, polygonal, in particular hexagonal, or polygonal with rounded corners.

[0015] In a further development of the invention, an angle (X) which a wall of the widening section forms with the central longitudinal axis of the through opening is greater than or equal to eight degrees and less than or equal to 45 degrees.

[0016] The wall angle of the expanding section is chosen as large as possible to create a large undercut. One limit to the wall angle is the deformability of the expansion collar; angles between approximately 10 degrees and 45 degrees have proven to be extremely advantageous.

[0017] In a further development of the invention, the expansion collar rests against the inner wall of the through-opening over the entire length of the through-opening.

[0018] This ensures secure anchoring of the fastener in the through-hole of the component. As described above, after the fastener is inserted into the through-hole, the expansion collar expands radially by plastic deformation until the expansion collar rests against the inner wall of the through-hole over the entire length of the through-hole.

[0019] In a further development of the invention, a free end of the expansion collar is arranged within the through-opening or flush with an underside of a section of the component surrounding the through-opening.

[0020] In this way, it is possible to ensure that the connecting element, and in particular the expansion collar, does not protrude beyond the underside of the component. This is achieved without the need to provide the component with indentations or the like. Nevertheless, the connecting element can be securely anchored in the through-hole of the component using the expansion collar.

[0021] In a further development of the invention, the through-opening has a high surface roughness at least in the region of the widening section.

[0022] In this way, the pull-out force of the connecting element can be significantly increased, and the connecting element is also reliably secured against twisting. When the connecting element is assembled, the expansion collar rests against the inner wall of the through-hole, at least in the area of ​​the widening section. A high surface roughness, which creates small depressions and small elevations in the inner wall, then leads to the material of the expansion collar engaging the depressions in the inner wall of the through-hole during plastic deformation of the expansion collar. The anchoring of the connecting element in the through-hole can therefore withstand even very high pull-out forces and torques.

[0023] In a further development of the invention, the through-opening has a first cylindrical section, wherein the widening section adjoins the first section, wherein the surface roughness in the region of the widening section is greater, in particular more than twice as great as the surface roughness in the first cylindrical section.

[0024] The anchoring of the expansion collar to the widening section of the through-hole is crucial for the achievable pull-out force of the fastener. A high surface roughness in the widening section therefore ensures reliable anchoring of the fastener.

[0025] In a method according to the invention for producing a through-opening in a component, wherein the through-opening is provided for inserting a connecting element according to the invention and the through-opening has at least one widening section, the formation of the through-opening during the production of the component is provided by means of punching, by means of primary forming, in particular by means of 3D printing, casting or injection molding, by forming the through-opening by means of machining processes, in particular drilling and / or milling, or by forming the through-opening by means of non-cutting processes.

[0026] In a further development of the invention, the production of a first, cylindrical section and an expanding section adjoining the first section is provided when forming the through-opening, wherein the cylindrical section starts from the beginning of the through-opening and the expanding section extends to the end of the through-opening.

[0027] When producing the through-hole, an angle that a wall of the widening section assumes with respect to the central longitudinal axis of the through-hole is set to a value between 8° and 45°. In a further development of the invention, the through-hole is formed by punching using a punch and a die, wherein the component is held in sections between the punch and die, and wherein a cutting gap between the die and punch amounts to 7.5% to 20%, in particular 10% to 15%, of the component thickness of the component in the region of the through-hole.

[0028] A cutting gap between the die and punch of between 7.5% and 20% of the component thickness is larger than a cutting gap usual for punching. This results in a punch with a first, cylindrical section of the through-hole and an expanding, in particular frustoconical, section in a second section of the through-hole, with the expanding second section being created by a violent fracture of the component material during punching. The enlargement of the cutting gap compared to cutting gap sizes usual for punching leads to the surprising result that the through-hole takes on a shape that is undesirable when punching through-holes, but which is ideal for inserting a connecting element with an expanding collar. When punching through-holes, the aim is always to achieve a through-hole that is cylindrical over its entire length.By selecting a suitable cutting gap, particularly a narrow cutting gap, the formation of a forced fracture during punching is minimized and at least largely avoided. The inventors have surprisingly discovered that a poor punching according to the rules of the art leads to the formation of a through-hole having a first, cylindrical section and a second, widening section, which is ideally suited for anchoring a fastener with an expanding collar. As explained, the widening section is created automatically when punching the through-hole due to a forced fracture of the component material in the second section. The cutting gap is defined as half the difference in diameter between the punch and die.

[0029] In a further development of the invention, the formation of a rough surface structure on the inner wall of the through-opening at least in the region of the frustoconically widening section is provided, in particular by generating a forced fracture in the region of the frustoconically widening section when punching the through-opening.

[0030] The deliberate acceptance of a violent fracture of the component material during punching of the through-hole not only creates a widened section of the through-hole, but also a rough surface structure on the inner wall of the through-hole in the area of ​​the widened section. Here, too, the deliberate acceptance of a violent fracture of the component material during punching, which is usually intended to be completely or largely avoided when punching through-holes, results in a through-hole design that is ideally suited for anchoring a connecting element according to the invention with an expanding collar.

[0031] In a method according to the invention for inserting a connecting element into a through-opening of a component, wherein the connecting element has an annular expanding collar protruding from an underside of the connecting element, wherein the expanding collar is designed such that it can be expanded in the radial direction by means of plastic deformation and wherein the through-opening has at least one widening section, the following steps are provided: inserting the expanding collar of the connecting element into the through-opening in the component such that the expanding collar is arranged at least in sections radially within the widening section of the through-opening, and spreading the expanding collar until an outer side of the expanding collar rests circumferentially against a wall of the widening section of the through-opening.

[0032] In the method according to the invention, the expansion collar is inserted such that the free end of the expansion collar is located on the side of the widening section with the largest diameter of the through-hole. As the expansion collar expands in the radial direction, an undercut is formed in the expansion collar when it rests against the inner wall of the through-hole. This allows the connecting element to be securely anchored in the through-hole of the component.

[0033] In a further development of the invention, the production of the through-opening in the component is provided by means of punching using a punch and a die, wherein a cutting gap between the punch and die is between 7.5% and 20%, in particular between 10% and 15%, of the thickness of the component in the region of the through-opening to be produced.

[0034] The selection of a cutting gap between punch and die dimensioned in this way leads, as already explained above, to the formation of a forced fracture of the component material during punching in a second section of the punched through-hole in the direction of movement of the punch through the component. Such a forced fracture not only causes a frustoconical widening of the through-hole, with the frustoconical section widening in the punching direction, but also the formation of a rough surface in the area of ​​the forced fracture, i.e. in the area of ​​the frustoconical widening section. By selecting a cutting gap that is larger than that usually set when punching through-holes, the through-hole is given an ideal shape for the secure anchoring of the connecting element according to the invention with a plastically deformable expansion collar.

[0035] In a further development of the invention, the impression of an annular recess by means of the die into a bottom side of the component facing the die and into a bottom side of the expansion collar facing the die is provided, wherein the recess is impressed along a contact line between the connecting element and the component on the bottom side of the component and the expansion collar.

[0036] The die expands the expansion collar radially until it rests against the inner wall of at least the frustoconically widening section of the through-hole. By further advancing the die toward the component, the annular recess is embossed by an annular projection on the die after the radial expansion of the expansion collar. This creates additional interlocking between the component and the expansion collar, thus resulting in a sealed connection between the connecting element and the component. Such a sealed connection can be important, for example, in battery applications where it must be ensured that the connection between the connecting element and the component is gas-tight.

[0037] In a further development of the invention, the material connection of the connecting element and the component is provided in the area of ​​the annular recess.

[0038] For example, the expansion collar and component are soldered or welded in the area of ​​the annular recess to create a sealed connection. The annular recess can also be filled with adhesive or sealant to create a sealed connection between the fastener and the component.

[0039] Further features and advantages of the invention will become apparent from the claims and the following description of preferred embodiments of the invention in conjunction with the drawings. Individual features of the various illustrated and described embodiments can be combined with one another in any way without exceeding the scope of the invention. This also applies to the combination of individual features without other individual features with which they are illustrated and / or described in connection.

[0040] The drawings show:

[0041] Fig. 1 is a partially sectioned side view of a connecting element according to the invention,

[0042] Fig. 2 is a sectional view of a component with a through-opening for inserting the connecting element of Fig. 1,

[0043] Fig. 3 is an enlarged partial view of detail III of Fig. 2,

[0044] Fig. 4 is a further sectional view of the component of Fig. 2, with an angle X being drawn,

[0045] Fig. 5 is a schematic representation of the component of Fig. 2 during punching of the through hole,

[0046] Fig. 6 is a partial sectional view of an arrangement with a connecting element according to the invention and a component,

[0047] Fig. 7 is a partially sectioned view of a component and a connecting element according to the invention when inserting the connecting element into the through-opening of the component in a first state,

[0048] Fig. 8 is a partially sectioned view of a connecting element according to the invention and a component during insertion of the connecting element into the through-opening of the component in a second state,

[0049] Fig. 9 shows a detail of an arrangement similar to Fig. 7 and Fig. 8 when inserting the connecting element into the through-opening according to a further embodiment, Fig. 10 shows a section-wise sectional view of a component, produced by primary forming or machining, with a through-opening according to a first embodiment,

[0050] Fig. 11 is a sectional view of a component produced by punching, with a through-opening according to a second embodiment,

[0051] Fig. 12 is a sectional view of a component produced by primary forming or machining, with a through-opening according to a third embodiment,

[0052] Fig. 13 is a sectional view of a component produced by punching, with a through-opening according to a fourth embodiment,

[0053] Fig. 14 is a sectional view of a component, produced by primary forming or machining, with a through-opening according to a fifth embodiment,

[0054] Fig. 15 is a sectional view of a component produced by punching, with a through-opening according to a sixth embodiment and

[0055] Fig. 16 is a partially sectioned side view of a connecting element according to the invention according to a seventh embodiment.

[0056] Fig. 1 shows a connecting element 10 according to the invention. The connecting element 10 has a cylindrical upper part 12, a likewise cylindrical main part 14 and an annular expansion collar 16 extending from an underside of the main part 14.

[0057] The left half of Fig. 1 shows a side view of the connecting element 10. In the side view, it is clearly visible that an outer diameter of the expansion collar 16 corresponds to the outer diameter of the upper part 12. Within the scope of the invention, there is no dependency between the outer diameter of the expansion collar 16 and the outer diameter of the upper part 12. Consequently, these diameters may also differ from one another.

[0058] The right half of the illustration in Fig. 1 shows a section through the connecting element 10. It can be seen that the upper part 12 is provided with a truncated cone-shaped recess 18 on its upper side. The upper part 12 has a circular-cylindrical outer wall. A shoulder is arranged between the upper part 12 and the main part 14, since the main part 14 has a larger outer diameter than the upper part 12.

[0059] A shoulder is also arranged between the main part 14 and an outer wall of the expansion collar 16, since the outer diameter of the expansion collar 16 is smaller than the outer diameter of the main part 14. As already explained, the outer diameter of the expansion collar 16 corresponds to the outer diameter of the upper part 12, although these outer diameters can also be different within the scope of the invention. A shoulder between the main part 14 and the expansion collar 16 is advantageous within the scope of the invention, since the connecting element 10 can then be placed with the underside of the main part 14 onto an upper side of the component (see Fig. 6), and the position of the connecting element 10 is thereby positioned relative to the component in the insertion direction of the connecting element 10.

[0060] The expansion collar 16 has a rectangular cross-section in the sectional view of Fig. 1. The wall thickness of the expansion collar 16 is therefore constant over its entire length. An outer wall of the expansion collar 16 is longer than an inner wall of the expansion collar, although deviations from this are possible within the scope of the invention. During radial expansion of the expansion collar 16, the outer wall of the expansion collar is therefore not expanded or only very slightly expanded in the radial direction in the upper section in Fig. 1. Deformation of the expansion collar during expansion therefore occurs primarily in the region of the rectangular cross-section of the expansion collar 16.

[0061] Fig. 2 shows a component 20 with a through opening 22 which is provided for inserting the connecting element 10 of Fig. 1.

[0062] It can be seen in Fig. 2 that the through opening 22 has an inlet section which is rounded and then has a first section 24 which is cylindrical, see Fig. 3. The cylindrical section is then followed by a second section 26 which widens in the shape of a truncated cone.

[0063] The enlarged view of detail III in Fig. 3, wherein Fig. 3 only shows a partial view of detail III, shows that the through-opening 22 has a total of three sections. Starting from an upper side of the component 20, wherein the component 20 is realized in the form of a sheet metal, the through-opening begins with the rounded inlet section 28. An inner wall of the inlet section 28 is convex. The inlet section 28 is followed by the cylindrical first section 24, which then widens into the frustoconical second section 26. The frustoconical second section 26 extends to the lower end of the through-opening 22 in Fig. 3, wherein the largest diameter of the frustoconical section 26 and the through-opening 22 is also arranged at the lower end of the through-opening 22.

[0064] The frustoconically widening section 26 widens in a direction from the top side of the component 20 in Fig. 3 to the bottom side of the component 20. When inserting the connecting element 10 of Fig. 1 into the through-opening 22, an undercut can form between the component 20 and the expanding collar 16 or connecting element 10 as the expansion collar 16 expands radially, in order to securely anchor the connecting element 10 in the through-opening 22.

[0065] An inner wall of the conically widening section 26 is shown in dotted lines in Fig. 3. This symbolizes that the inner wall of section 26 has a greater surface roughness than the cylindrical section 24.

[0066] Fig. 4 shows a further sectional view of the component 20 of Fig. 2 with the through-opening 22. In Fig. 4, an angle of the frustoconically widening section 26 is indicated by X. The angle X results when punching the through-opening 22 due to the size of a cutting gap and the material properties of the component 20. Alternatively, the angle X can be adjusted during the primary forming of the component 20 or during the production of the through-opening 22 by means of machining processes.

[0067] Fig. 5 shows an arrangement for producing the through-opening 24 in the component 20 by means of punching. The component 20 is shown in Fig. 5 without the through-opening 22. In the state of Fig. 5, a punch 30 for punching the through-opening 22 rests on an upper side of the component 20. An underside of the component 20 rests on a die 32, wherein the die 32 has an opening 34 into which a punched-out slug from the component 20 can enter during punching of the through-opening 22 and into which the punch 30 can move in sections during punching.

[0068] The punch 30 has an outer diameter that is smaller than an inner diameter of the opening 34 in the die 32. The difference between the diameters of the punch 30 and the opening 34 in the die 32 is referred to as the cutting gap between the die and punch. This cutting gap is designated by reference symbol S in Fig. 5. The cutting gap is circumferential when the punch and die are correctly positioned.

[0069] The through-hole 22 in the component 20, as shown in Figs. 2, 3, and 4, is formed by punching, as explained using the punch 30 schematically shown in Fig. 5 and the die 32, also schematically shown. Within the scope of the invention, the cutting gap S is selected to be larger than is usual when punching through-holes. When punching through-holes, the aim is usually to ensure that the resulting through-hole is cylindrical over most of its length. Deviations from the cylindrical shape of the through-hole may occur at the beginning and end of the through-hole.When punching through-holes, the cutting gap S is usually selected to be as small as possible in order to achieve a clean punching effect and thus the most cylindrical shape of the through-hole possible, particularly in the last section of the punching process, i.e. before the punched-out slug is completely detached from the component 20.

[0070] Within the scope of the invention, this conventional procedure is deviated from in that a cutting gap between the opening 34 of the die 32 and the punch 30 is selected to be larger than usual, so that the cutting gap amounts to 7.5% to 20%, in particular 10% to 15% of the component thickness of the component 20. The cutting gap is thus larger than a cutting gap usual in punching. This leads to a violent fracture of the material of the component 20 during punching. Specifically, when the punch 30 is pressed into the component 20, the first section 28 of the through-opening 22 is first formed, see Fig. 3. In the process, the surface of the component 20 which is arranged under the punch 30 is pressed a short distance into the component 20, resulting in the rounded configuration of the inner wall of the entry section 28.If the punch 30 is then pressed further during the punching process, the material of the component 20 is sheared off by the outer edges of the punch 30, so that the cylindrical first section 24 is formed. The cutting gap S enlarged according to the invention causes a forced fracture of the material of the component 20 during the punching process. This is because the cutting gap S is too large to achieve a cutting or punching effect all the way to the underside of the component 20. As a result, the slug is pushed out by the punch 30 and the sections of the material of the component 20 that still connect the slug to the component 20 break off as the punch 30 is fed further forward. This is referred to as forced fracture during punching. Such a forced fracture during punching results in the conically widening second section 26 of the through-opening, see Fig. 3, which not only, as shown in Fig.3, has a rougher surface structure than the cylindrical section 24, but widens in the feed direction of the punch 30, i.e. from the top side of the component 20 to the bottom side of the component 20 in a frustoconical shape with the angle X, see Fig. 4.

[0071] It was determined within the scope of the invention that such a forced fracture, which is actually undesirable when punching through-holes, leads to the formation of the punched through-hole 22, which is ideal for anchoring the connecting element 10 according to the invention by radially expanding the expansion collar 16. The deliberate enlargement of the cutting gap compared to expertly recognized rules during punching leads to an increased formation of a forced fracture and a longer frustoconically widening section 26. Depending on the requirements for anchoring the connecting element 10 according to the invention in the component 20, the cutting gap S can be selected to vary in size. This leads to a different formation of the through-hole 22 during punching, in particular to different length ratios of the cylindrical section 24 and the frustoconically widening section 26.Corresponding different designs of the through opening 22 by means of punching are shown in Figs. 11, 13 and 15.

[0072] Within the scope of the invention, the through-opening 22 can also be produced in a manner other than punching, for example by primary forming, in particular by means of 3D printing, casting or injection molding, or by means of machining processes, in particular drilling, countersinking and / or milling. By means of such processes, the angle X and the length of the frustoconically widening section 26 can then be adjusted to the requirements of the respective application. Through-openings produced by primary forming or machining processes are shown in Figs. 10, 12 and 14. By means of primary forming or machining processes, the through-opening 22, for example in a sheet metal, can also be formed exclusively conical or frustoconical without a cylindrical section.

[0073] Fig. 6 shows a section-wise sectional view of an arrangement with the connecting element 10 according to the invention of Fig. 1 and the component 20 according to the invention, wherein the connecting element 10 has already been inserted into the through-opening 22 of the component 20 and anchored in this through-opening 22.

[0074] From Fig. 6 it can be seen that the connecting element 10 was placed with the underside of the main part 14 onto the top side of the component 20 and that the expanding collar 16 was subsequently expanded in the radial direction so that an outer wall of the expanding collar 16 bears against the inner wall of the through-opening 22. It can be seen in Fig. 6 that the outer wall of the expanding collar 16 bears against the inner wall of the through-opening 22 essentially over the entire length of the through-opening 22. Only in the lowest part of the through-opening 22 in Fig. 6 can a gap with a triangular cross-section be seen between the inner wall of the through-opening 22 and the outer wall of the expanding collar 16. This gap can, if necessary, be used to arrange a sealing means, for example adhesive or sealing compound, in order to achieve a sealed connection between the connecting element 10 and the component 20.This is useful, for example, when component 20 forms a cover plate for a battery and the connection between connecting element 10 and component 20 is to be watertight and gas-tight. However, the triangular gap between the outer wall of expansion collar 16 and the inner wall of through-hole 22 in component 20 can also be filled with solder, for example, or used to weld expansion collar 16 and component 20 together in this area to create a sealed connection.

[0075] Fig. 7 shows a partially sectioned view of an arrangement after insertion of the connecting element 10 into the through-hole of the component 20, but before radial expansion of the expansion collar 16 of the connecting element 10.

[0076] The expansion of the expansion collar 16 in the radial direction is effected by means of a die 40, which is shown in Fig. 7 below the underside of the component 20 and which has a frustoconical elevation 42 on its upper side, which is adapted to the dimensions of the expansion collar 16. A hold-down device above the connecting element 10 is not shown for the sake of clarity.

[0077] The enlarged detail in Fig. 7 shows that after the insertion of the connecting element 10, the expansion collar 16 is still cylindrical and is arranged with its lower end in Fig. 7 flush with the underside of the component 20. The flush arrangement is not mandatory within the scope of the invention; ideally, the lower end of the expansion collar will protrude slightly from the underside of the component 20. The frustoconical elevation 42 on the upper side of the die 40 extends somewhat into the expansion collar 16 before the start of deformation. As the die 40 is fed further towards the underside of the component 20, the frustoconical elevation 42 will penetrate into the central recess surrounded by the expansion collar 16 and, by means of its frustoconical outer wall, will press the expansion collar 16 radially outwards.The expansion collar 16, in particular the entire connecting element 10, consists of a plastically deformable material, in particular a plastically deformable metal, for example aluminum, so that the radial expansion of the expansion collar 16 leads to a plastic deformation of the expansion collar 16, so that the connecting element 10 is then permanently anchored in the through-opening 22 of the component 20.

[0078] Fig. 8 shows the state of the arrangement in Fig. 7, in which the die 40 has been moved so far against the underside of the component 20 that an upper side of the die 40, which surrounds the frustoconical elevation 42 of the die, rests against an underside of the component 20. Fig. 8 thus shows the state in which the die 40 has reached the end of its feed path in the direction of the component 20. As can be seen from Fig. 8, in this state the frustoconical projection 42 has spread the expanding collar 16 radially outwards and at the same time plastically deformed it. Plastic deformation of the expanding collar can also be seen in the fact that in Fig. 8 the expanding collar 16 is now thinner at the lower end than at its upper end. An outer wall of the expansion collar 16 now lies against the inner wall of the through opening 22 essentially over the entire length of the through opening 22.Only in the rounded entry section of the through-opening 22 extending from the top of the component 20 is there a small gap between the connecting element 10 and the component 20. This gap plays no significant role in the pull-out force or secure anchoring of the connecting element 10 in the through-opening 22 of the component 20. This gap can be completely avoided by appropriately designing the through-opening 22, the connecting element 10 and / or the die 40, and optionally a counterholder (not shown in Fig. 7 and Fig. 8).

[0079] At the end of the through-opening 22, i.e., shortly before the transition of the inner wall of the through-opening 22 into the underside of the component 20, the inner wall of the through-opening 22 is exposed. In the embodiment shown in Fig. 8, the expansion collar 16 was deliberately chosen to be somewhat shorter than the thickness of the component 20 or the length of the inner wall of the through-opening 22. This ensures that the underside of the expansion collar 16 is still within the through-opening 22 or, at most, is flush with the underside of the component 20.

[0080] Fig. 9 shows the state of the arrangement of Fig. 8 in enlarged detail when using a die 140 according to a further development of the invention. In contrast to the die 40 of Figs. 7 and 8, the die 140 has an annular projection 144 that surrounds the frustoconical elevation 42 on the upper side of the die 140. The annular projection 144 is designed such that it imprints an annular depression into the underside of the arrangement comprising the component 20 and the connecting element 10. The annular depression then lies partly in the material of the component 20 and partly in the material of the connecting element 10 or the expanding collar 16. This annular depression leads to additional plastic deformation of the component 20 and the expanding collar 16 in the region of the contact surface between the connecting element 10 and the component 20.This allows for a particularly tight connection in the region of the contact surface immediately adjacent to the annular recess, thus creating a sealing effect between the expansion collar 16 and the component 20. The annular recess can also be filled with a sealant or an adhesive, or used to solder or weld the connecting element 10 and the component 20 together in the region of the annular recess to achieve a sealed connection.

[0081] Figs. 10 to 15 show various configurations of a through-hole in component 20. The through-holes of Figs. 10, 12, and 14 were produced by primary forming, in particular by 3D printing, casting, or injection molding, or by machining processes, in particular drilling and / or milling. The through-holes of Figs. 11, 13, and 15 were produced by non-cutting processes, in particular punching.

[0082] Fig. 10 shows that the through-opening 22 in the component 20 has a convex, rounded entry section extending from the top of the component 20 and then transitioning into a cylindrical section 24. The cylindrical section 24 is followed by the frustoconically widening section 26. The frustoconically widening section 26 is longer than the entry section and the cylindrical section 24 combined. Within the scope of the invention, the cylindrical section 24 and the rounded entry section can be omitted when forming the through-opening. The frustoconically widening section 26 is essential for anchoring the connecting element 10. The through-opening 22 can be produced, for example, during casting or injection molding of the component 20, or by milling and / or drilling. The surface roughness of the through-opening 22 is the same over its entire length and in all sections 24, 26.

[0083] Fig. 12 shows a component 20 with a through-opening 22 that was formed identically to the through-opening 22 in Fig. 10, i.e., by means of primary forming during manufacture of the component or subsequently by means of machining processes. In contrast to the through-opening 22 in Fig. 10, the through-opening 22 in Fig. 12 has a longer cylindrical section 24 and a correspondingly shorter, frustoconically widening section 26. In the embodiment in Fig. 12, the convexly rounded inlet section and the cylindrical section 24 together are approximately the same length as the frustoconically widening section 26. The surface roughness of the through-opening 22 is the same over its entire length and in all sections 24, 26.

[0084] Fig. 14 shows a component 20 with a through-opening 22 that was formed in the same way as the through-openings 22 in Figs. 10 and 12, for example by means of primary forming during the manufacture of the component 20 or subsequently by means of machining processes. The through-opening 22 has a convexly rounded entry section and a cylindrical section 24, as well as, adjoining the cylindrical section 24, the frustoconically widening section 26. The frustoconical section 26 is shorter than the cylindrical section 24 and, consequently, also shorter than the combined length of the convex, rounded entry section and the cylindrical section 24. The surface roughness of the through-opening 22 is the same over its entire length and in all sections 24, 26.

[0085] Depending on the intended application, the material of the component 20 and the material of the connecting element 10, the formation of the through opening 22 can be carried out in different ways, as explained with reference to Figs. 10, 12 and 14.

[0086] Fig. 11, 13 and 15 each show the component 20 with differently formed through openings 22. In the case of Fig. 11, 13 and 15, the through openings 22 were each formed by means of punching, as already explained with reference to Fig. 2 to 5.

[0087] Fig. 11 shows the component 20 with the through-opening 22, which was already explained with reference to Fig. 3. The formation of a comparatively large cutting gap between the punch 30 and the opening 34 in the die 32, see Fig. 5, leads to the formation of the through-opening 22 with the convexly rounded entry section 28, the cylindrical first section 24 and the frustoconically widening second section 26 with a rough surface structure. It can be seen from Fig. 11 and Fig. 3 that the cylindrical section 24 is considerably shorter than the frustoconically widening section 26 and is only approximately one-third the length of the frustoconically widening section 26. The frustoconical section 26 is longer than the entry section 28 and the cylindrical section 24 combined. A surface roughness is larger in section 26, in particular twice as large, as in sections 24, 28.

[0088] Fig. 13 shows the component 20 with a through-opening 22, in which the frustoconical widening section 26 is shorter than in the embodiment of Fig. 11. The frustoconical section 26 has approximately the same length as the convexly rounded inlet section 28 and the cylindrical section 24 combined. As already explained, the conically widening section 26 with a rough surface structure is created by generating a forced fracture of the material of the component 20 when punching the through-opening 22. The frustoconically widening section 26, which is shorter than in the embodiment of Fig. 11, is achieved by reducing the cutting gap S, see Fig. 5. Compared to the cutting gap S when creating the through-opening 22 in Figs. 3 and 11, a smaller cutting gap is therefore selected when creating the through-opening 22 in Fig. 13.A surface roughness is larger in section 26, in particular twice as large, as in sections 24, 28.

[0089] Within the scope of the invention, the different design of the through-hole 22 can of course also be achieved by using a different material for the component 20. For the same cutting gap, a more brittle material for the component 20 generally results in a more severe fracture, i.e., a longer, frustoconically widening section 26.

[0090] Fig. 15 shows the component 20 with a through-hole 22, which is designed such that the frustoconically widening section 26 is shorter than the cylindrical section 24. The frustoconical section 26 was formed by a forced fracture of the material of the component 20 during punching of the through-hole 22. Compared to the through-holes in Figs. 3, 11, and 13, a smaller cutting gap S was selected to form the through-hole 22 in Fig. 15, with the same material of the component 20 (see Fig. 5). The surface roughness is greater in section 26, in particular twice as great as in sections 24, 28.

[0091] Fig. 16 shows a connecting element 200 according to a seventh embodiment of the invention. The connecting element 200 is designed as a so-called expanding rivet bolt. The connecting element 200 has an upper part 202, which is in the form of a screw bolt and has a thread. The connecting element 200 also has a cylindrical main part 214 and an annular expanding collar 216 extending from the underside of the main part 214. Within the scope of the invention, there is no dependency between the outer diameter of the expanding collar 216 and the outer diameter of the upper part 202. In the illustrated embodiment, the outer diameter of the annular expanding collar 216 is larger than the outer diameter of the upper part 202, whereby these outer diameters can also be the same or the outer diameter of the upper part 202 can be larger than the outer diameter of the expanding collar 216. In the right half of the illustration in Fig.Figure 16 shows a section of the connecting element 200. It can be seen that a shoulder is arranged between the upper part 202 and the main part 214, since the main part 214 has a larger outer diameter than the upper part 202.

[0092] A shoulder is also arranged between the main part 214 and an outer wall of the expansion collar 16, since the outer diameter of the expansion collar 216 is smaller than the outer diameter of the main part 214. Fig. 16 shows that a circumferential groove is arranged in the horizontal annular surface 204 of this shoulder, which extends into the main part 214. This groove 204 is intended to receive material that spreads upwards when the connecting element 200 is inserted into a through opening when the expansion collar 216 is expanded in the radial direction, as already explained with reference to the connecting element 10 in Fig. 1.

[0093] The connecting element 200 is, as explained with reference to the connecting element 10 in Fig. 1, inserted into a through-opening 22 of a component 20 in the manner of the connecting element 10 (see Fig. 6), whereupon the expanding collar 216 is expanded in the radial direction, so that an outer wall of the expanding collar 216 then bears against the inner wall of the through-opening 22. The connecting element 200 is consequently anchored in the same way as the connecting element 1 in Figs. 1 and 6, and the through-opening 22 is also designed in the same way as has already been explained with reference to the connecting element 1 and in particular Figs. 1 to 15.

Claims

Patent claims 1. Connecting element for insertion into a through-opening of a component, wherein the through-opening in particular has at least one widening section, characterized by an annular expansion collar projecting from an underside of the connecting element, wherein the expansion collar is designed such that it can be expanded in the radial direction by means of plastic deformation.

2. Connecting element according to claim 1, characterized in that the connecting element consists of a plastically deformable metallic material, in particular aluminum, at least in the region of the expansion collar.

3. Connecting element according to claim 1 or 2, characterized in that, seen in cross section, an outer contour of the expansion collar is circular, elliptical, polygonal, in particular hexagonal, or polygonal with rounded corners.

4. Connecting element according to claim 1, 2 or 3, characterized in that, seen in cross section, an inner contour of the expansion collar is circular, elliptical, polygonal, in particular hexagonal, or polygonal with rounded corners.

5. An arrangement comprising a connecting element, in particular according to one of the preceding claims, and at least one component connected to the connecting element, characterized in that the connecting element has an annular expansion collar projecting from a bottom side of the connecting element, in that the component has a through-opening, wherein the through-opening has at least one widening section, wherein the expansion collar of the connecting element extends into the through-opening and bears at least in sections against an inner wall of the widening section of the through-opening, in that the through-opening has a high surface roughness at least in the region of the widening section, and in that the through-opening has a first, cylindrical section, wherein the widening section adjoins the first section,wherein a surface roughness in the region of the widening section is greater, in particular more than twice as great as the surface roughness in the first, cylindrical section., 6. Arrangement according to claim 5, characterized in that the through-opening has a first, cylindrical section, the widening section adjoining the first section.

7. Arrangement according to claim 5 or 6, characterized in that the widening section is frustoconical or truncated pyramidal.

8. Arrangement according to claim 5, 6 or 7, characterized in that, seen in cross section, the widening section is circular, elliptical, polygonal, in particular hexagonal, or polygonal with rounded corners.

9. Arrangement according to claim 5, 6, 7 or 8, characterized in that an angle (X) which a wall of the widening section forms with the central longitudinal axis of the through opening is greater than or equal to eight degrees and less than or equal to 45 degrees.

10. Arrangement according to one of the preceding claims 5 to 9, characterized in that the expansion collar rests against the inner wall of the through-opening over the entire length of the through-opening.

11. Arrangement according to one of the preceding claims 5 to 10, characterized in that a free end of the expansion collar is arranged within the through-opening or is arranged flush with an underside of a section of the component surrounding the through-opening.

12. A method for producing a through-opening in a component, wherein the through-opening is provided for inserting a connecting element according to claim 1, 2, 3 or 4, wherein the through-opening has at least one widening section, characterized by forming the through-opening during the production of the component by means of punching, by means of primary forming, in particular by means of 3D printing, casting or injection molding, by forming the through-opening by means of machining processes, in particular drilling and / or milling, or by forming the through-opening by means of non-cutting processes.

13. The method according to claim 12, characterized by producing a first cylindrical section and an expanding section adjoining the first section when forming the through opening, wherein the cylindrical section starts from the beginning of the passage opening and the widening section extends to the end of the passage opening.

14. Method according to claim 12 or 13, characterized in that an angle (X) which a wall of the widening section forms with the central longitudinal axis of the through-opening is greater than or equal to eight degrees and less than or equal to 45 degrees.

15. The method according to claim 12, 13 or 14, characterized by forming the through-opening by means of punching using a punch and a die, wherein the component is received in sections between the punch and the die and wherein a cutting gap between the die and the punch is 7.5% to 20%, in particular 10% to 15%, of the component thickness.

16. The method according to claim 15, characterized by forming a rough surface structure on the inner wall of the through-opening at least in the region of the widening section, in particular by producing a forced fracture in the region of the frustoconically widening section during punching of the through-opening.

17. A method for inserting a connecting element into a through-opening of a component, wherein the connecting element has an annular expansion collar protruding from an underside of the connecting element, wherein the expansion collar is designed such that it can be expanded in the radial direction by means of plastic deformation, wherein the through-opening has at least one widening section, characterized by the steps: inserting the expansion collar of the connecting element into the through-opening in the component so that the expansion collar is arranged at least in sections radially within the widening section of the through-opening and spreading the expansion collar until an outer side of the expansion collar rests at least in sections circumferentially against a wall of the widening section of the through-opening.

18. The method according to claim 17, characterized by producing the through-opening in the component by means of punching using a punch and a die, wherein a cutting gap between the punch and die is between 7.5% and 20%, in particular between 10% and 15%, of the thickness of the component in the region of the through-opening to be produced.

19. Method according to claim 17 or 18, characterized by embossing an annular depression by means of the die into an underside of the component facing the die and into an underside of the expansion collar facing the die, wherein the depression is embossed along a contact line between the connecting element and the component on the underside of the component and the expansion collar.

20. Method according to claim 19, characterized by materially bonding the connecting element and the component in the region of the annular recess.

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