Connecting element and method for connecting two workpieces

Abstract

A connection element for connecting two workpieces and a corresponding method are provided. The connection element includes a head and a cylindrical shank extending from a bottom of the head. The shank includes a base portion extending from the bottom of the head. The shank includes a tip portion forming an end of the shank distal from the head. The shank also includes a rib portion between the base portion and the tip portion. The rib portion includes a plurality of ribs.

Description

Technical Field

[0001] The present invention relates to a connecting element (particularly a connecting element for hole-forming connection) for connecting at least two workpieces, a corresponding connecting method, and the use of said connecting element in hole-forming connection methods (particularly flow drilling fastening methods or flow drilling screw connection methods). Background Technology

[0002] Connecting elements are known and used to join workpieces, components, or parts together. In the case of threaded connecting elements, material is not removed from the workpiece to create threads for the connecting element before connection; instead, the material of the workpiece is shaped or deformed to form threads within it. However, a small amount of material is removed from the workpiece when the threaded connecting element is inserted. Some threaded connecting elements can also form holes in the workpiece, in which the connecting element is disposed. The hole can be formed simultaneously with the thread. Threaded connecting elements that can also form holes can be referred to as threaded and hole-forming connecting elements or hole-forming connecting elements.

[0003] To insert the threaded connecting element into the workpiece, the fastening element is rotated while in contact with the first workpiece, thereby heating the first workpiece and indirectly the second workpiece. The connecting element is then inserted into the first workpiece, pressing through it and into the second workpiece. Throughout the connection operation, the threaded connecting element rotates. As a result, threads are formed in the workpiece.

[0004] The connecting element and the workpiece to be connected can be matched to each other so that the connecting element will not pierce the surface of the second workpiece. Then, in the area of ​​the connecting element, a protrusion is formed on the unpierced surface.

[0005] WO2023214164A1 discloses a threaded and holed connecting element. The connecting element includes a head and a shank defining a longitudinal axis. The shank includes a shank portion and a tip portion. The shank portion extends from the head. The tip portion extends from the shank portion and is disposed opposite the head. At least a portion of the shank portion is threaded.

[0006] It has been found that when a threaded connector is inserted, the starting end of the threaded portion of the connector can act like a knife, potentially producing long, thread-like material chips. These chips can become entangled around the head of the connector and prevent complete insertion.

[0007] In the case of machining tools, it is known to arrange a so-called "chip breaker" that causes the chips to bend and break, thereby crushing the chips.

[0008] However, the chips that may be generated during hole-forming connection methods (especially flow drill screw connection methods) are difficult to break or break into relatively small fragments because they are generated during hot working and therefore have high ductility.

[0009] DE102010046318A1 relates to a threadless connecting element, but the connecting element itself must deform during the connection process in order to create a secure connection joint between two abutting connecting parts.

[0010] KR1020040090612A relates to a riveting method in which material is locally melted. The riveting method is implemented as a double-sided joining method.

[0011] WO02 / 062518A1 relates to a fastening element that uses a material of similar hardness and deforms together with the workpiece. Summary of the Invention

[0012] Therefore, a connecting element is needed that at least partially reduces the aforementioned problems in the prior art. Furthermore, the objective is to provide a connecting element that avoids the generation of long material chips during flow drilling fastening. Additionally, the objective is to provide a connecting element that ensures a more secure connection between two workpieces. Furthermore, a method corresponding to the connecting element is also needed.

[0013] At least one of the above-described technical objectives is achieved by a connecting element or connecting method according to the independent claim. Further embodiments are specified in the dependent claims.

[0014] In one independent aspect of the invention, a connecting element for connecting two workpieces is provided. The connecting element includes a head and a cylindrical rod extending from the base of the head. The rod includes a base portion extending from the base of the head. The rod includes a pointed portion forming one end of the rod away from the head. The rod also includes ribs located between the base portion and the pointed portion. The ribs include a plurality of ribs.

[0015] In another independent aspect of the invention, a connecting element for forming a hole to connect two workpieces is provided. The connecting element includes a head and a cylindrical rod extending from the base of the head. The rod includes a base portion extending from the base of the head. The rod includes a tip portion forming an end of the rod remote from the head. The rod also includes ribs located between the base portion and the tip portion. The ribs include a plurality of ribs, each rib surrounding the rod in its respective plane and including a constant rib projection. These planes are parallel to each other. The ribs cover at least 30% of the rod.

[0016] In another independent aspect of the invention, a method for forming a hole to connect two workpieces is provided. The method includes: providing a first workpiece, a second workpiece, and a connecting element according to one aspect of this disclosure; placing the connecting element on a surface of the first workpiece; rotating the connecting element at a predetermined rotational speed; and applying a predetermined axial force to the connecting element in a direction toward the surface of the first workpiece.

[0017] In another independent aspect of the invention, the use of a connecting element according to one aspect of this disclosure in a flow drill fastening method is provided.

[0018] The core of this invention lies in covering at least a substantial portion (e.g., at least 30%) of the shank by multiple parallel ribs (instead of the typically arranged threads). Thus, the connecting element at least partially loses its screw-like characteristics. Unlike the grooves of threads, the groove between two adjacent ribs or rib protrusions is limited to the circumferential length of the shank. As a result, the chips produced in the hole-forming connection method are shorter than those in threads. Although at least partially replacing threads, the connecting element can still be used in single-sided connection methods, such as flow drilling fastening methods. The multiple ribs and the grooves formed between them do not have a helical shape. Therefore, chip removal surfaces like those in threads can be avoided. Experiments show that the function of the connecting element is maintained compared to, for example, the threaded connecting element described in WO 2023 / 214164 A1. Deformed material from the two workpieces can flow into the groove between two adjacent ribs. Furthermore, it has been found that the multiple ribs ensure a thread-like locking interface in the joint of the two workpieces, and also reduce the risk of incomplete insertion of the connecting element and prevent vibration-induced loosening. In other words, since the threads of the connecting element are at least partially replaced by multiple ribs, the threads are prevented from acting as a cutting device and producing long, thread-like material residue, and the connecting element is prevented from falling off or being manipulated due to vibration. Because of the non-helical grooves between the multiple ribs, any formed material threads cannot be pulled out and, for example, wrapped around the head of the connecting element.

[0019] The connecting element and / or the method or the use of the connecting element may also include one or more of the following features.

[0020] Each rib of the rib section can surround the rod section in its own plane.

[0021] At least one rib may be substantially perpendicular to the axis of the rod.

[0022] Each rib in the rib section may include a constant rib protrusion and / or a constant rib diameter.

[0023] Ribs can be formed parallel to each other. Ribs can be oriented parallel to each other around the plane containing the rod.

[0024] The ribs can cover at least 30% of the rod, preferably 50% of the rod.

[0025] The ribs can completely cover the shaft portion between the base and tip portions. The shaft portion can be completely slotted between the base and tip portions, i.e., without any smooth sections. The ribs can cover at least 40%, preferably at least 50%, and more preferably at least 60% of the shaft portion between the base and tip portions. All ribs of the ribs can surround (particularly completely surround) the shaft portion in their respective planes and can each include a constant rib projection or include the same rib diameter. The rib diameter can correspond to or be equivalent to the outer diameter of the shaft portion.

[0026] The two workpieces can each be flat workpieces, and they can directly contact each other through planar contact surfaces. The connecting element is preferably introduced or inserted into the two workpieces that are stacked on top of each other in the area of ​​the planar contact surface.

[0027] The shank can be formed of a material that is harder than the materials of the two workpieces (preferably at least 50% harder). The term "hardness" refers to the mechanical resistance of a material or workpiece to the mechanical penetration of another object (such as a connecting element). This difference in hardness between the shank and the workpieces to be connected ensures better control over material displacement within the workpieces and a stronger connection between the two workpieces.

[0028] The base portion may have a diameter corresponding to or equal to the diameter of the rib or rib in the region adjacent to the rib. The tip portion may have the largest diameter in the region adjacent to the rib. The largest diameter of the tip portion may be smaller than the diameter of the rib or rib. In other words, the outer shell of the rod may taper gradually at the transition from the rib to the tip portion. As a result, material displacement in the first workpiece and / or the second workpiece can be improved.

[0029] A constant rib protrusion can mean that the ribs have the same height relative to the rod in the circumferential direction around the rod. Each rib may include a circular cross-section. Each rib may be rotationally symmetric with respect to the axis of rotation of the connecting element. The rod may include a circular cross-section and / or be rotationally symmetric with respect to the axis of rotation of the connecting element.

[0030] The connecting element can be inserted into two workpieces on one side, meaning there is no second component supporting the side opposite the connecting element to the two workpieces.

[0031] The connecting element may also include a threaded portion located between the rib and the base portion. The threaded portion may include threads, particularly external threads. The threaded portion may be formed on the shank portion axially closer to the head than the rib. The rib may directly abut the tip portion. As a result, long material chips can be avoided equally effectively, as the threaded portion can create an additional clamping effect in the region near the head of the connecting element. Advantageously, the width of the threaded portion is chosen to correspond to (in particular equal to) the thickness of the first workpiece. As a result, the threaded portion can more effectively secure the first workpiece relative to the second workpiece in the formed joint.

[0032] Ribs may include symmetrical rib faces. Each rib may include a symmetrical rib face. The term "rib face" refers to a longitudinal section passing through one or more abutting rib protrusions. Each rib or each rib protrusion may include a first side face and a second side face. A symmetrical rib face may mean that the first side face and the second side face are mirror-symmetrical in the longitudinal section. The plane forming the respective rib can be used as a mirror. The mirror can be perpendicular to the axis of rotation of the connecting element, or intersect the axis of rotation at an angle not equal to 90°.

[0033] The axis of rotation of the connecting element can be coaxial with the longitudinal axis of the rod.

[0034] Ribs may include asymmetrical rib faces. Each rib may include an asymmetrical rib face. A first side of the rib protrusion may face the head. A second side of the rib protrusion may face the tip portion. The first side may intersect a plane (which intersects both sides and is parallel to the rib) at a first angle. The first angle may be less than or greater than a second angle at which the second side intersects the plane. In other words, the rib may include a serrated shape in the longitudinal section. Asymmetrical rib faces can improve material flow or material displacement between two workpieces and increase resistance to pull-out or tearing.

[0035] Ribs, individual ribs, and / or each rib may include a trapezoidal shape in the longitudinal section. Optionally, or additionally, ribs, individual ribs, and / or each rib may include a circular shape, a serrated shape, and / or a triangular shape in the longitudinal section.

[0036] A circumferential groove can be formed between every two ribs. Each groove can include a constant groove depth. The groove depth can vary axially along the shank, particularly increasing towards the tip. This can mean that a deeper groove is formed between two ribs closer to the tip compared to two further adjacent ribs (i.e., between two further adjacent ribs). All ribs can have the same outer diameter. The diameter of the shank can vary axially, particularly being tapered or gradually tapering. This can result in grooves having different groove depths at different axial locations.

[0037] The rib protrusion or rib may include a first circular shape in the longitudinal section, and / or the groove may include a second circular shape between the ribs in the longitudinal section. The second circular shape may include a curvature opposite to that of the first circular shape. The first and second circular shapes may include curvatures of the same magnitude. In other words, the rib and / or groove may be rounded or circular.

[0038] A groove with a first groove width can be formed between every two ribs. At least one groove may include a second groove width greater than the first groove width. Preferably, one of the grooves with the second groove width connects the tip portion to the groove portion. In other words, the grooves of the ribs may include a mixture of large and small grooves. It may be advantageous if the tip portion and the rib are connected by a groove that is larger (i.e., wider and / or deeper) compared to the other grooves, in order to reduce the resistance of the connecting element penetrating the two workpieces.

[0039] The axis of rotation of the connecting element can intersect the plane of the rib perpendicularly or at an angle not equal to 90°. This means that the ribs of the rib can be positioned horizontally or obliquely, but cannot be a mixture of horizontal and oblique positioning. The difference between obliquely positioned ribs and threads is that individual grooves are formed between multiple ribs, while threads only include a single groove.

[0040] The tip may not include grooves, threads, and ribs.

[0041] The head may also include a buckle. The buckle may be adjacent to the rod portion, and in particular extend around the rod portion. The buckle may be configured to receive material from the first workpiece and / or the second workpiece when using the connecting element.

[0042] The head may also include a hexagonal device through which the connecting tool transmits torque to the connecting element.

[0043] The tip portion may include a tapered shape to form the largest possible contact surface with the first workpiece when placed on its surface. Friction between the connecting element and the first workpiece is caused by the rotation of the connecting element and the application of an axial force to it. The connecting element penetrates the first workpiece according to the axial force and the material properties of the first workpiece. When the connecting element penetrates so deeply into the first workpiece or both the first and second workpieces that the groove of the recessed portion contacts the first workpiece, a groove profile corresponding to the groove of the recessed portion is formed in the first and / or second workpieces as the connecting element penetrates further.

[0044] Due to the rotation of the connecting element, the first workpiece and the second workpiece passing through it are heated. In this case, the rotation is configured to heat the first and / or / second workpieces only to a processing temperature of approximately 300°C. The first and / or second workpieces may comprise aluminum with a melting point of 660°C. It can be ensured that the process temperature remains below the melting point of the first and / or second workpieces, i.e., melting of either the first or second workpiece does not occur. As a result, the material of the first and / or second workpieces remains around and below the recrystallization temperature in the hot forming region, thus avoiding problems associated with hot forming, such as grain growth and loss of localized mechanical properties, while improving ductility compared to cold forming.

[0045] Preferably, before or during the placement of the connecting element on the surface of the first workpiece, there are no holes in the region of the first or second workpiece that is axially aligned with the axis of rotation of the connecting element. That is, the connecting element can be introduced into the first and second workpieces without pre-punching the first and / or second workpieces.

[0046] If the first and second workpieces are connected to each other, the tip portion may be surrounded by the first and / or second workpieces. Specifically, if the connecting element has penetrated to its final depth in the first and second workpieces, the tip portion may be surrounded by the first and / or second workpieces. If the first and second workpieces are connected to each other, or if the connecting element has penetrated to its final depth in the first and second workpieces, the tip portion may not protrude beyond the first and / or second workpieces. The tip portion may be at least partially surrounded by a protrusion formed in the second workpiece. If the first and second workpieces are connected to each other, or if the connecting element has penetrated to its final depth in the first and second workpieces, the surface of the second workpiece may not be pierced by the connecting element.

[0047] The first and / or second workpiece can be components. Specifically, the first and / or second workpiece can comprise or be composed of metal. Preferably, the first workpiece is a metal element or metal component, particularly a steel element or steel component. The first workpiece can also be an aluminum component. The aluminum component can be composed of or include said alloys such as AA5000, AA6000, or AA7000. The second workpiece can be a metal element or metal component, particularly an aluminum element or aluminum component. Particularly preferably, the second workpiece is an aluminum die-casting element. The second workpiece can be a non-heat-treated aluminum die-casting element. Similarly, the second workpiece can be an aluminum die-casting element with a high proportion of recycled aluminum, i.e., a high proportion of recycled aluminum. The second workpiece can be composed of or include said alloy AA7000. Attached Figure Description

[0048] The present invention, or further embodiments and advantages thereof, will now be described in more detail with reference to the accompanying drawings, which illustrate only embodiments of the invention. In the drawings, the same parts are referred to by the same reference numerals. Elements drawn with dashed lines are considered optional.

[0049] Figure 1 A perspective side view of a first example of a connecting element according to an embodiment of the present disclosure is shown.

[0050] Figure 2a It shows Figure 1 A longitudinal cross-sectional view of the connecting element.

[0051] Figure 2b It shows Figure 2a The enlarged area in the longitudinal cross-sectional view.

[0052] Figure 3a A longitudinal cross-sectional view of a second example of a connecting element according to an embodiment of the present disclosure is shown.

[0053] Figure 3b It shows Figure 3a The magnified area in the longitudinal cross-sectional view.

[0054] Figure 4 A longitudinal cross-sectional view of a third example of a connecting element according to an embodiment of the present disclosure is shown.

[0055] Figure 5 A longitudinal cross-sectional view of a fourth example of a connecting element according to an embodiment of the present disclosure is shown.

[0056] Figure 6 A longitudinal cross-sectional view of a fifth example of a connecting element according to an embodiment of the present disclosure is shown.

[0057] Figure 7 A longitudinal cross-sectional view of a sixth example of a connecting element according to an embodiment of the present disclosure is shown.

[0058] Figure 8a A perspective side view of a seventh example of a connecting element according to an embodiment of the present disclosure is shown.

[0059] Figure 8b It shows Figure 8a A longitudinal cross-sectional view of the connecting element.

[0060] Figure 9a A perspective side view of an eighth example of a connecting element according to an embodiment of the present disclosure is shown.

[0061] Figure 9b It shows Figure 9a A longitudinal cross-sectional view of the connecting element.

[0062] Figure 10A longitudinal cross-sectional view of the connecting element after use in a method according to an embodiment of the present disclosure is shown. Detailed Implementation

[0063] In the following text, unless otherwise stated, the same reference numerals are used to denote the same and functionally identical elements. The elements shown should not be considered to be drawn to scale; for better understanding, individual elements may be shown at an enlarged size.

[0064] Figure 1 A first example of a connecting element 100 according to an embodiment of the present disclosure is shown. The connecting element 100 has a head 10 and a rod 20. The rod 20 extends from the head 10, more specifically from the bottom of the head 10. The head may include a hexagonal device 12 for connecting the connecting element 100 to a connecting tool.

[0065] exist Figure 1 In the example, the rod portion 20 can be divided into three regions. The base portion 21 directly adjacent to and extends from the bottom of the joint portion 10. The base portion 21 is preferably rotationally symmetrical with respect to the axis of rotation RA.

[0066] Along the Z-axis, rib 22 is immediately adjacent to base portion 21. Rib 22 includes a plurality of ribs 1, wherein a groove 2 may be formed between two directly adjacent ribs 1. Figure 1 In the example, rib 1, or more precisely, each rib 1, is trapezoidal in shape. In the trapezoidal shape, the smaller base can be substantially smaller than the larger base. Rib 1 includes a rib projection 1h, which can also be referred to as the rib height. The rib projection 1h, or rib height, corresponds to the groove depth. Groove 2 also includes a groove width 2w, which can be defined between the tips of the two ribs 1 forming groove 2. Figure 1 In the example, all ribs 1 are formed in the same way. Ribs 1 are formed parallel to each other and perpendicular to the axis of rotation RA. Each rib 1, and therefore rib 22 itself, has a diameter 1d, which can be larger than the (inner) diameter 2d of the rod 20, the diameter 2d corresponding to the diameter of the groove 2. Therefore, the reference numeral "1d" indicates the rib diameter, and the reference numeral "2d" indicates the groove diameter. The groove 2, ribs 1, and rib 22 can be rotationally symmetrical with respect to the axis of rotation RA.

[0067] The base portion may have a diameter corresponding to the diameter 1d of rib 1.

[0068] Figure 2a It shows Figure 1 A longitudinal cross-sectional view of an example of the connecting element 100.

[0069] To clarify the parallel planes formed by rib 1 therein, Figure 2a A dashed line is drawn through rib 1.

[0070] exist Figure 2a In the longitudinal cross-section, with Figure 1 In contrast, one can also see the inverted buckle 11 of the head 10, and the base portion 21 extending from the inverted buckle.

[0071] Figure 2b The details A of the rod 20 are shown. In the longitudinal sectional view, rib 1 and the groove 2 formed between the rib 1 are highlighted. Figure 1 , 2a In examples 2b and 2b, each rib 1 may include the same rib protrusion amount 1h. Figure 2b In the enlarged view, it can be clearly seen that the maximum diameter of the tip portion 23 directly adjacent to the rib 22 can be smaller than the diameter 1d of the rib 1, but larger than the diameter 2d of the groove 2. Therefore, the tip portion 23 can be tapered relative to the rib 22.

[0072] Figure 3a and 3b A second example of the connecting element 100 is shown. (With) Figure 2b similar, Figure 3b It shows Figure 3a Magnified details A.

[0073] and Figure 1 , 2a Compared to the connecting element 100 in example 2b, Figure 3a and 3b In the example, the connecting element 100 has a circular rib 1 and a groove 2. This means that the rib 22 is circular in longitudinal section. The curvature of the circular shape of the rib 1 can be substantially opposite to the curvature of the circular shape of the groove 2. Figure 3a and 3b The remaining characteristics and features of the connecting elements are applicable to the reference. Figure 1 , 2a The characteristics and features described in 2b.

[0074] exist Figure 3b In the enlarged image, with Figure 2b Compared to the trapezoidal shape, the shape of rib 22 is circular.

[0075] Figure 4 A third example of the connecting element 100 is shown. Figure 4 In the example, with Figure 1 , 2a Compared to example 2b, the rib protrusion 1h can vary along the axial direction Z. That is, in this configuration, grooves 2, 2′ can include different groove diameters 2d, 2d′ and / or different groove widths 2w, 2w′. Grooves 2, 2′ with different groove diameters 2d, 2d′ and / or different groove widths 2w, 2w′ can be mixed in rib 22.

[0076] A first groove 2 and a second groove 2' can be formed between every two ribs 1. The first groove 2 may include a first groove width 2w, and the second groove 2' may include a second groove width 2w'. Preferably, the tip portion 23 and the rib 22 are connected by the second groove 2'. In other words, the last groove 2 in the axial direction Z is preferably the second groove 2'. It is further advantageous to form two, three, or four second grooves 2', especially in the half of the rib 22 that is closer to the tip portion 23 relative to the base portion 21.

[0077] Figure 5 A fourth example of the connecting element 100 is shown. Figure 5 In the example, each groove 2 may include a different groove diameter 2d, while the rib diameter 1d of all ribs may be the same. In particular, the groove diameter 2d may continuously decrease or taper in the axial Z direction with successive grooves 2. The (inner) diameter of the rod portion 20 may be tapered. The rib protrusion 1h of the rib 1 may increase in the axial Z direction with successive ribs 1, particularly continuously. As a result, the groove 2 closer to the tip portion 23 and penetrating deeper into at least two workpieces can receive more deformable material from the workpieces than the groove 2 closer to the base portion 21. Therefore, the resistance to penetration of the connecting element 100 into the two workpieces can be reduced.

[0078] Figure 6 A fifth example of the connecting element 100 is shown. Figure 6 In the example, rib 22, rib 1, and / or each of rib 1 may include asymmetrical rib faces, particularly serrated shapes. As shown in more detail in the enlarged circular section, the first side of rib 1 may face the base portion 21 or the head 10, while the second side may face the tip portion 23. Furthermore, the plane of the rib protrusion 1h with its maximum extent is drawn in dashed form. Figure 6 In the longitudinal section, the first side surface and the second side surface intersect the plane. In this case, the first side surface may intersect the plane more steeply than the second side surface. In other words, the first side surface may form a first angle α with the plane, and the second side surface may form a second angle β with the plane. The first angle α may be greater than the second angle β. Or, as... Figure 7 As shown, the first angle α can be smaller than the second angle β. In the case of a symmetrical ribbed surface, for example in... Figure 1 , 2a In 2b, the first angle α and the second angle β can be equal in magnitude.

[0079] Figure 8a and 8bA seventh example of a connecting element 100 is shown. Contrary to all other examples described according to embodiments of this disclosure, the connecting element 100 may include a rod portion 20 that includes a threaded portion 24 in addition to a rib portion 22. The threaded portion 24 may include threads, particularly external threads, i.e., a single groove. The rib portion 22 may be as shown in reference... Figure 1-7 The configuration is as described in 9a and 9b. Rib 22 may be closer to tip portion 23 than threaded portion 24. In other words, rib 22 may extend from threaded portion 24 in the axial Z direction.

[0080] Figure 8b It shows the relationship with Figure 8a The corresponding longitudinal sectional view shows the transition from the threaded portion 24 to the rib 22 indicated by dashed lines. Furthermore, the selection of the parallel plane of the rib 1 surrounding the shank 20 is indicated by dashed lines.

[0081] Figure 9a and 9b An eighth example of the connecting element 100 is shown. Figure 9a In the example, rib 1 is inclined relative to head 10 about a parallel plane of shank 20. Rib 1 or its corresponding plane may form an angle not equal to 90° with the axis of rotation RA. The axis of rotation RA may intersect the plane of the rib at an angle not equal to 90°. Unlike in threads, each rib 1 is formed in its own plane, where rib 1 or plane is placed parallel to each other. The choice of these planes is... Figure 9b The longitudinal section is indicated by dashed lines. Figure 9a , 9b In rib 22, the groove diameter 2d can be constant in the axial direction Z. For clarity, the axial direction is... Figure 4-9a Not shown in 9b, but the results are similar to Figure 1 similar.

[0082] exist Figure 1-7 In the examples 9a and 9b, the rib 22 can completely cover the rod portion 20 between the tip portion 23 and the base portion 21. Thus, the rod portion 20 can be completely unthreaded.

[0083] Although individual features of the rib 22 are described in different examples of the connecting element 100, the connecting element 100 may include combinations of the described features. Therefore, Figure 4 and 5 Rib 1 may include a circular shape in the longitudinal section. Furthermore, Figure 6 and 7 The serrated shape can be according to Figure 4 Alternating groove widths 2w, 2w′ combinations, and / or including according to Figure 5 The changing diameter of the groove.

[0084] Figure 10 A longitudinal cross-sectional view (photograph) of the connecting element 100 after use in a method according to an embodiment of the present disclosure is shown.

[0085] In the first step, a first workpiece, a second workpiece, and a connecting element 100 are provided (as described above). The first and second workpieces can be as follows: Figure 10 The planar workpiece is shown. The first workpiece can be placed on top of the second workpiece. (Example) Figure 10 As shown, at the connection point, neither workpiece has a hole or any dent.

[0086] In the second step, the connecting element 100 is placed on the surface of the first workpiece. The connecting element 100 can be placed on the first workpiece using a connecting tool, particularly a clamping device. As a result, the connecting element 100 can directly contact the surface of the first workpiece. The connecting element 100 can be placed on one side only, that is, without any auxiliary structures on the opposite side of the second workpiece.

[0087] In the third step, the connecting element 100 is rotated at a predetermined speed. Due to the direct contact between the connecting element 100 and the first workpiece, and the resulting friction, the first workpiece is heated by the rotation. Heating the first workpiece to a maximum of 300°C can be used as the process temperature.

[0088] In the fourth step, a predetermined axial force is applied to the connecting element 100 in the direction toward the surface of the first workpiece. As a result, the connecting element 100 can be pressed into the first workpiece, and subsequently into the second workpiece. For example, an example range of predetermined rotational speeds and predetermined axial forces can be found in DE 10 2024 110303 A1.

[0089] The connecting element 100 has not yet fully passed through the second workpiece. Instead, a protrusion has been formed so that the rod portion 20 of the connecting element 100 is fully embedded in both workpieces.

[0090] By means of the connecting element according to the invention, shorter chips are naturally generated in the hole-forming connection method compared to connecting elements with threaded adjacent tip portions. The plurality of ribs 1 and the grooves 2 formed between them do not have a helical shape. Therefore, chip-removing surfaces as in threads can be avoided, thereby reducing thread-like material residue and thus reducing the risk of the connecting element falling off or being manipulated due to vibration.

Claims

1. A connecting element for connecting two workpieces, the connecting element comprising: head; as well as A rod extending from the bottom of the head, the rod comprising: The basal portion extending from the bottom of the head; The pointed portion forming the end of the rod furthest from the head; and A rib located between the base portion and the tip portion, the rib comprising multiple ribs.

2. The connecting element according to claim 1, wherein each rib of the rib surrounds the rod in its respective plane.

3. The connecting element according to claim 1, wherein each rib of the rib portion is perpendicular to the rod axis.

4. The connecting element according to claim 1, wherein each rib of the rib portion has a constant rib protrusion and / or a constant rib diameter.

5. The connecting element according to claim 1, wherein the ribs of the rib portion are formed parallel to each other, and / or the ribs are parallel to each other around the plane containing the rod portion.

6. The connecting element according to claim 1, wherein the rib covers at least 30% of the rod portion.

7. The connecting element according to claim 1, wherein the rib covers 50% of the rod portion.

8. The connecting element according to claim 1 further includes a threaded portion located between the rib and the base portion.

9. The connecting element according to claim 1, wherein the ribs of the rib portion have asymmetrical rib profiles.

10. The connecting element according to claim 1, wherein the rib is trapezoidal in longitudinal section.

11. The connecting element according to claim 1, wherein a circumferential groove is formed between every two ribs, each circumferential groove having a constant groove depth, and the depth of the circumferential groove varies along the axial direction of the rod portion, particularly increasing towards the tip portion.

12. The connecting element of claim 1, wherein the rib completely covers the area between the base portion and the tip portion.

13. The connecting element according to claim 1, wherein the ribs of the ribs are in a first circular shape in the longitudinal section, and / or the circumferential grooves between the ribs are in a second circular shape in the longitudinal section, wherein the second circular shape has a curvature opposite to that of the first circular shape.

14. The connecting element according to claim 13, wherein the curvature of the first circular shape and the second circular shape are the same.

15. The connecting element according to claim 1, wherein a groove having a first groove width is formed between every two ribs, wherein at least one groove has a second groove width greater than the first groove width.

16. The connecting element of claim 15, wherein one of the grooves having a second groove width connects the tip portion to the groove portion.

17. The connecting element according to claim 1, wherein the axis of rotation of the connecting element intersects the plane of the rib perpendicularly or at an angle not equal to 90°.

18. A method for producing a hole-forming joint for two workpieces, the method comprising: A first workpiece, a second workpiece, and a connecting element according to claim 1 are provided; Place the connecting element on the surface of the first workpiece; Rotate the connecting element at a predetermined speed; as well as A predetermined axial force is applied to the connecting element in the direction toward the surface of the first workpiece.

19. The method of claim 18, wherein the method is a flow drilling fastening method.

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