Press-in element, method for forming press-in connection, and press-in connection

Abstract

In order to form a press-in connection (4) with a pre-punched part (6), the press-in element (2) has a head (8) with a head bearing surface (16) and a pressing edge (20) which is connected to the head (8) in a press-in direction (12). The blank (20) has a base section (22) and a filling section (24), wherein the filling section (24) is connected to the base section (22) forming an inner step (26) oriented towards the central axis (10). In this way, in the production method, a reliable filling of the annular gap (58) between the stamping edge (38) of the stamping die (32) and the hole wall (30) with the edge material is achieved by volumetric shaping of the edge material, thereby ensuring good pull-out resistance as well as torsional moment resistance and water tightness.

Description

Technical Field

[0001] The present invention relates to a press-fit element having the features of claim 1, a method for forming a press-fit connection, and a press-fit connection. Background Technology

[0002] Such press-fit elements and such press-fit connections can be found, for example, in DE 10 2016 204 619 B4. The press-fit connection described therein has a high-strength component, particularly a high-strength sheet metal, into which the press-fit element is pressed. A problem with such press-fit connections is that, due to the high strength, the component itself cannot deform or can only deform very poorly.

[0003] In the context of this application, a high-strength component refers to a component with a strength greater than 600 MPa, particularly greater than 800 MPa, and preferably up to 2200 MPa. Besides cold-formed steel, the component can also be made of hot-formed, press-hardened steel. The press-fit elements used for this purpose, particularly press-fit nuts, typically have a strength of about 1000 MPa, particularly a strength grade of FK 10. The thickness of the component (plate), and therefore the wall thickness, is typically between 1.5 mm and 4 mm.

[0004] A particular method is described in DE 10 2016 204 619 B4, in which the upset edge of the pressed-in element is pressed against the hole wall of the pre-drilled part by volume forming. Upsetting in the sense of flanging is not performed here, nor is forming in the sense of radial expansion that would introduce tangential tensile stress. Similarly, the part itself does not deform due to its high strength.

[0005] Press-fit connections can also be found, for example, in DE 24 41 977 C2 or DE 10 2012 220 033 A1. These describe press-fit nuts with polygonal upset edges for anti-rotation. According to US 2007 / 0166128 A1, for anti-rotation purposes, the holes in the component are also additionally formed with a polygonal circumferential profile. Summary of the Invention

[0006] Therefore, the purpose of this invention is to achieve a reliable press-fit connection between press-fit elements and, in particular, high-strength components in a process-reliable manner.

[0007] According to the invention, this objective is achieved by a press-fit element having the features of claim 1, by a method for manufacturing a press-fit connection having the features of claim 12, and by a press-fit connection having such a press-fit element having the features of claim 19.

[0008] The advantages and preferred embodiments stated in relation to the press-in element, method, or press-in connection may be applied accordingly to each other.

[0009] This press-fit element is particularly a press-fit nut. Besides nuts, it can also be a press-fit element with a through hole, especially without internal threads. A self-tapping screw or wire thread is then inserted into this through hole, for example.

[0010] This press-fit element is used to form a press-fit connection with a pre-drilled, particularly high-strength, component. The press-fit element extends along a central axis in the press-fit direction. The press-fit direction also defines the longitudinal direction. The press-fit element has a head with a head support surface, typically annular, which rests on the upper side of the component during press-fit formation. In the press-fit direction, an upsetting edge, also known as a forming edge, is connected to the head. During press-fit formation, a form-locking and / or friction-locking connection is achieved, particularly through volume forming, with the hole, especially with the hole wall of the pre-drilled component.

[0011] Regarding a reliable joining process, the upsetting edge has a base section connected to the head and an upsetting edge section further connected longitudinally thereto, called the fill section. The upsetting edge typically extends from the underside of the head in the pressing direction and is generally formed as a loop. Therefore, the two sections are also formed as loops. This loop can have a circular or polygonal profile, such as a hexagonal profile. Thus, the respective inner or outer surfaces of the upsetting edge, and consequently the corresponding inner or outer surfaces of the two sections, form a circumferentially closed annular surface.

[0012] The filler section connects to the base section by forming an inner step, thus facing the central axis. The base section typically has an axial base height extending in the pressing direction from the head support surface to the step. Furthermore, the filler section typically has an axial fill height extending from the step to the leading edge of the upsetting flange in the pressing direction.

[0013] A step is generally understood as a (ring-shaped) surface extending radially between the base section and the fill section. Therefore, this ring-shaped surface—compared to the base and fill sections—is oriented with a particularly smaller angle of inclination relative to the horizontal plane, and extends particularly parallel or at least substantially parallel to the horizontal plane. At least substantially perpendicular is understood as an angle of inclination (relative to the horizontal plane) of at most + / - 20°, and preferably at most + / - 10°. The longitudinal direction forms the normal to the horizontal plane.

[0014] The upper end of the base section, which is also one end of the upsetting edge, is located at the axial height of the head support surface and is therefore defined by the head support surface. The lower end of the upsetting edge is defined by the front end of the fill section and the free end on the end face side.

[0015] The upset blank is also designed to be threadless, that is, even when the press-in element is designed to press into a nut, it has no (internal) thread along its entire axial length.

[0016] In manufacturing press-fit connections, the press-fit element is typically inserted into a hole in the front insert component with its upset edge, the hole having circumferential walls. The upset edge is formed using a die with a front punch area, specifically such that the edge material is pressed against the hole wall, and in particular, the underside of the component is not pressed against the upset edge from the rear. The front punch area is designed in the form of a front stamped edge, and will be referred to as such hereinafter. The component in question is particularly a high-strength component, especially a sheet metal having the strength defined at the beginning for high-strength components.

[0017] When forming a press-fit connection, similar to the method described in DE 10 2016 204 619 B4, volumetric forming is mainly performed in three-dimensional space, so that the upset edges, especially the base section, are upset using a die. Here, the edge material is pressed against the hole wall through volumetric forming to form a press fit with the hole wall.

[0018] Therefore, conventional forming is not performed, where the upset edge is expanded radially outward and adheres to the underside of the part from below. In this volumetric forming, edge material pressure forming is essentially performed, similar to forging.

[0019] Accordingly, the total height of the upset edge, consisting of the base height and the fill height, is preferably less than or equal to the thickness of the component into which the press-in element is to be inserted, in the initial state before press-in and especially after press-in. The total height is typically sized such that the upset edge does not extend beyond the underside of the component in the completed press-in connection.

[0020] Because the upset edge bears considerable force during the upseting process, it is designed to be threadless at least along its entire length. This avoids deformation of the threads that might be introduced during upseting.

[0021] Therefore, the press-fit element is typically designed to form a press-fit connection with high-strength components, as will be described in particular in detail below.

[0022] The description of forming a push-in connection in DE 10 2016 204 619 B4 is incorporated herein by reference, particularly paragraphs 19 and 20 and paragraphs 22 and 24.

[0023] Through a stepped design with a base section and a fill section, the upsetting edge generally has a step-like shoulder on its radially inner side. Therefore, the central cavity surrounded by the upsetting edge expands in a stepped manner at the transition from the base section to the fill section. Consequently, the fill section has a significantly smaller wall thickness compared to the base section and is designed to be very fine and thin overall. A particular advantage of this leading fill section with a small wall thickness is that the edge material (of the fill section) can penetrate deeper between the die and the hole wall, especially in press-in methods where the upsetting edge does not enter or fully enter the hole of the part at the beginning of the press-in process. The special design of the upsetting edge ensures that the edge material is reliably and as completely as possible filled and pressed against the hole wall along its entire or at least almost the entire axial length (height) of the hole.

[0024] Therefore, during the press-fit connection, the pre-fill section preferably enters the circumferential free annular space (gap) between the front imprint edge of the die and the hole wall to achieve the desired complete filling and pressing along the entire axial length of the hole. This also means that the outer diameter of the front imprint edge is preferably smaller than the inner diameter of the hole, thus creating the annular gap.

[0025] For the forming itself, the front stamping edge presses against the upsetting edge against the pressing direction, especially against the step. Thus, volume forming is achieved through displacement and the resulting material flow. The material flows radially and thus forms a press fit with the hole wall. The material also partially avoids axial flow, giving the material flow an axial component, which causes the material to flow axially downwards in the pressing direction as well.

[0026] The design of the upset edge with a base section and a filler section is specifically based on the consideration that, for the formation of a press-fit connection, the process technology typically requires that the die be first introduced forward from below into the hole of the component with its front imprint edge, and then the press-fit element be introduced from above and pressed against the die by a suitable indenter. This means that at the beginning of the press-fit process, the nut with the upset edge does not enter, or at least not completely enters, the hole. The aforementioned particular advantage is now achieved through the thin filler section on the radially outer side, which enters the free annular space between the hole wall and the front imprint edge, thereby enabling reliable material bonding with the hole wall along the entire axial length of the hole.

[0027] Therefore, when creating a press-fit connection, it is preferably performed as follows: first, the front stamping edge enters the hole, and then the press-fit element is pressed against the die from above. Thus, at the start of the press-fit process, the press-fit element does not enter, or at least not fully enters, the hole; that is, at the start of the press-fit process, the head support surface does not rest on the upper side of the component. Simultaneously, at the start of the press-fit process, the component's lower side is already resting on the support surface of the die, which is designed as an annular shoulder. The annular shoulder forms the support surface of the die. Therefore, during the press-fit process, the press-fit element is axially displaced in the direction toward the component, while the component is already supported on the die, particularly on the annular shoulder. Especially in this press-fit process, a high-quality press-fit connection is ensured in a process-reliable manner by filling the section.

[0028] In a preferred design, the fill height is between 20% and 100% of the base height, particularly between 30% and 60%. The fill height is preferably generally less than the base height. The total height of the upsetting edge is preferably in the range of, for example, 1.5 mm to 4 mm. It preferably corresponds to or is less than the thickness of the component (plate thickness). This thickness is generally preferably between 1 mm and 4 mm, particularly in the range of 1.5 mm to 3 mm.

[0029] The wall thickness (width) of the base section and the fill section are defined by the base thickness and the fill thickness, respectively. The base thickness and the fill thickness are determined at half the base height or half the fill height, respectively. The fill thickness is preferably in the range of 5% to 40% of the base thickness, particularly in the range of 10% to 30% of the base thickness. Therefore, the fill section is designed to be significantly thinner than the base section, allowing it to enter the annular gap (free annular space) between the front imprint edge of the die and the hole wall.

[0030] In a preferred further configuration, the aforementioned step has a radial step width, and the upset edge has a radial edge width at the height of the step, wherein the radial step width is in the range of 20% to 80% of the radial edge width, particularly in the range of 30% to 60% of the radial edge width. The radial edge width at the axial height of the step consists of the radial step width and the radial width of the filling section at that axial height.

[0031] The radial step width is generally understood as the radial extension of the step. A step is typically formed by a (ring-shaped) surface that extends radially between the base section and the fill section.

[0032] As a result, the step has a very large radial step width, which causes the inner surface of the upsetting edge in the step area to be significantly offset outward in the radial direction.

[0033] The step is generally preferably parallel or at least substantially parallel to a horizontal plane oriented perpendicular to the longitudinal direction and therefore also perpendicular to the central axis. Substantially parallel is understood as an orientation with a maximum inclination angle of + / - 20° and preferably a maximum of + / - 10°, referred to as the step angle.

[0034] In a preferred embodiment, the steps are oriented with an outward tilt, causing them to descend outward in the longitudinal direction. The step angle is particularly in the range of 1° to 15°, preferably between 3° and 8°.

[0035] In a design that meets the intended purpose, the base section and the fill section (in their initial, undeformed state) transition seamlessly to each other at their outer peripheries. That is, the upsetting edge does not have a shoulder or step on its outer circumferential side. Therefore, the base section and the fill section transition linearly to each other on their outer circumferential sides. According to a preferred design, the base section and the fill section form a common outer circumferential side extending parallel to the central axis. Alternatively, this common outer circumferential side extends at a tapered angle, specifically outwardly tapered relative to the central axis. The tapered angle is, for example, in the range of only a few degrees (1°–10°).

[0036] As an alternative to this design, the base section and the fill section transition linearly to each other on the circumferential side. The outer side of the fill section, or preferably the entire fill section (and therefore also the inner side), is angularly oriented relative to the base section and / or obliquely inward at an outer tilt angle relative to the pressing direction, thus tilting towards the central axis. This creates an infeed slope through the fill section, facilitating the insertion of the upsetting edge into the hole. The outer side, or the entire fill section, is tilted here, for example, at an outer tilt angle between 5° and 30°, preferably between 10° and 20°.

[0037] The inner side of the upsetting edge, opposite the outer circumferential side, is typically oriented obliquely relative to the central axis, or more obliquely to the central axis than the outer circumferential side. The inner side then descends obliquely outward. Therefore, the inner diameter defined by the upsetting edge expands when viewed in the pressing direction.

[0038] The inner side of the upsetting edge in the filling section area is hereinafter referred to as the lower inner section, and the inner side of the base section area is hereinafter referred to as the upper inner section. The lower inner section is preferably inclined at a downward (inward) angle relative to the pressing direction, wherein this downward / inward inclination angle is particularly in the range of 10°-40°, especially between 15° and 30°. The lower inner section is here particularly inclined outward (positive downward inclination angle). Alternatively, it may also be inclined inward (negative downward inclination angle).

[0039] The upper inner section is preferably inclined outward at an upper (inner) tilt angle, wherein the tilt angle is preferably in the range of 10°-40°, particularly 15° to 30°.

[0040] Preferably, the lower inner section and the upper inner section extend parallel to each other or at least substantially parallel to each other, and for example have an inclination angle with a maximum difference of + / - 20°.

[0041] In a preferred further development, an upper wall section is connected to the upper inner side against the pressing direction. This upper wall section extends more steeply relative to the pressing direction than the upper inner side, for example, until a cylindrical design is formed. The upper wall section has a smaller angle of inclination compared to the upper inner side.

[0042] A particularly advantageous feature is achieved by using a steeper upper wall section, which creates a groove that results in less material being present in the upper wall section area. This effectively prevents the material from being displaced inward during pressing and, for example, from deforming the threads formed there.

[0043] As mentioned at the beginning, this press-fit element, in particular a press-fit nut, therefore has a through hole with internal threads. Viewed in the press-fit direction, the internal thread ends particularly before the beginning of the base section. Specifically, the internal thread ends before or at the beginning of the upper wall section.

[0044] Typically, in the press-fit connection that has been formed, the head rests directly on the upper side of the component with its head support surface, thus resting on the circumferential edge of the hole.

[0045] In a preferred design, the upsetting edge has a polygonal, particularly hexagonal, outer contour to form an anti-rotation feature. Preferably, the entire head has this polygonal outer contour.

[0046] The holes in the component preferably have the same polygonal circumferential profile as the upsetting edge.

[0047] In order to form a push-in connection—in particular, as a supplement to what has been described so far—the following steps are preferably performed:

[0048] According to a preferred variation, the component is first placed on the die, particularly on the annular shoulder of the die, such that the front imprinting edge enters the hole. The pressing element is then pressed against the die from above. The imprinting edge etchs and defines a predetermined imprinting profile.

[0049] The front stamping edge preferably has a radially outwardly extending end face that is pressed against the step during the stamping process and subjected to an axial forming force, which causes the desired radial material displacement and shaping. This end face is here particularly linearly extended. Alternatively, it may extend horizontally or descend outwards.

[0050] The end face preferably transitions to the circumferential side of the front stamping edge through a transition region. The transition region is formed by chamfering or rounding.

[0051] During the pressing process, the end face presses the upset edge material upwards, thereby pressing the upset edge outwards against the hole edge. The transition area of ​​the die is specifically designed for deformation joints, preventing the die from sticking to the press-in joint and / or preventing the die from breaking at a sharp edge. The edge material is redirected here, but not bent outwards. This is the flow of the edge material.

[0052] The dimensions of the front stamping edge and the upsetting edge are coordinated in such a way that, at the start of the pressing process, the filling section impacts the transition area with its lower inner section and is reliably guided by it during the pressing process, so that the filling section can reliably enter the circumferential gap between the front stamping edge and the hole wall.

[0053] The upsetting process is initiated by a die and its (straight) end face. When the component strikes this end face, the upsetting edge is upset upwards and thus flows radially towards the hole edge. The edge material is thus filled between the hole edge and the die. The edge material then flows outwards around the radius formed by the transition region. Conventional bending is not performed; that is, the die does not bend the upsetting edge material outwards.

[0054] Therefore, during the press-fit connection, the end face acts on the step in the opposite direction of the press-fit. This causes volumetric deformation, which in turn causes the edge material to flow into the gap, i.e., into the circumferential annular space or free space, and is radially pressed against the hole wall. Preferably, only the axial force component is applied to the step. In particular, radial expansion is not performed here.

[0055] In a suitable further development, the end face is designed as an annular surface, which is defined by an annular edge protruding axially in the opposite direction of the pressing inward toward the central axis; this annular edge is also called the profile edge. This profile edge prevents the edge material from displacing inward toward the central axis. This ensures that the upsetting edge material is reliably pressed radially outward against the hole wall.

[0056] Typically, the geometry of the upsetting edge, the stamped edge, and the hole are coordinated within strict tolerances to achieve at least one, and preferably all, of the following properties in press-fit connections:

[0057] The head support surface rests directly on the upper side of the component.

[0058] The pressed-in component does not extend beyond the underside of the component.

[0059] The lower side is not pressed against the back edge.

[0060] The upsetting edge pressed against the hole wall extends beyond the entire or at least almost the entire axial length of the hole wall. Almost the entire length is understood to be a deviation of a maximum of 10%, and preferably a maximum of 5%. However, preferably, the upsetting edge extends beyond the entire length.

[0061] The component is not deformed in the area of ​​the hole, that is, the lower edge of the hole is not bent / raised, otherwise part of the upsetting edge may stick to the bent part from the back.

[0062] This component is a high-strength component.

[0063] This component is a pre-drilled component.

[0064] The hole is formed prior to the pressing process by a suitable hole-forming process, particularly by shearing (stamping). For parts made of hot-formed steel, the hole-forming process can optionally be performed before or after the heat treatment of the part. Alternatively, a laser cutting process can also be used. Furthermore, the hole can be introduced into the part by machining such as milling or drilling. The hole edge extends substantially parallel to the central axis. Particularly during stamping, as the stamping punch is pushed through the part in the pressing direction, a slight tear or fracture occurs on the lower side at the edge of the hole wall due to process reasons, causing the hole wall there (and thus particularly only in the lower half or lower two-thirds) to radially expand at a small angle of a few degrees. Furthermore, the surface of the hole wall is roughened in the torn portion, i.e., at the fracture surface. This expansion and radial pressing against the hole wall provides sufficient pull-out protection axially against the pressing direction.

[0065] This specifically relates to press-fit nuts. Alternatively, they can also be press-fit bolts. In press-fit bolts, a shank, particularly a threaded shank, is connected to the head, extending along a central axis in the press-fit direction. The shank is surrounded by an upsetting flange with a special geometry having a base section and a filler section, typically leaving an annular gap. Attached Figure Description

[0066] An embodiment of the present invention is described in more detail below with the aid of the accompanying drawings. These drawings show:

[0067] Figure 1 This is a cross-sectional view illustrating a method for forming a press-fit connection using a press-fit nut as a press-fit element, a pre-drilled component, and a die, wherein at the beginning of the process, said component is placed on the die and the press-fit nut is subsequently pressed in.

[0068] Figure 2 It is similar to Figure 1 The cross-sectional view shows that, in a further stage of the pressing process, the press-in nut impacts the die.

[0069] Figure 3 This is another cross-sectional view during a further stage of the press-in process, where the press-in nut is fully pressed in.

[0070] Figure 4 This is a top view of the nut being pressed in.

[0071] Figure 5This is a view from below of the nut being pressed in.

[0072] Figure 6 yes Figure 1 Enlarged view of the section marked with A in the image.

[0073] Figure 7 yes Figure 1 Enlarged view of the section marked with B in the image, and

[0074] Figure 8 It is similar to Figure 6 A diagram illustrating the alternative variant.

[0075] In each figure, components with the same function are labeled with the same reference numerals. Detailed Implementation

[0076] The press-in element shown in each figure is designed as a press-in nut 2. It is used to form with a pre-drilled component 6, designed as a sheet metal, by means of a press-in process. Figure 3 The push-in connection 4 is visible in the image, as shown in the image. Figures 1 to 3 As described.

[0077] The press-fit nut 2 typically has a head 8 that extends along a central axis 10 in a press-fit direction 12, which also defines the longitudinal direction. The press-fit nut 2 has a central through-hole in which an internal thread 14 is formed. In the press-fit direction 12, a head support surface 16 is formed on the underside of the head 8, with a step, and this head support surface is formed by a circumferential annular support surface. In the press-fit connection 4, the head support surface 16 rests on the upper side 18 of the component 6.

[0078] Starting from the head support surface 16, a circumferential annular upsetting edge 20 extends in the pressing direction 12. It is divided into an upper base section 22 and a lower filling section 24. The two sections 22 and 24 transition into each other by forming a step 26.

[0079] The precise geometry of the press-in nut 2 in the upset edge 20 region is described below with the aid of Figure 6 The enlarged image provides a more detailed explanation.

[0080] Component 6 is designed as a high-strength pre-drilled steel plate with the strength defined at the beginning. It has a hole 28 with a hole wall 30 into which a press-in nut 2 is pressed.

[0081] The pressing process is carried out using a pressing mold 32. Its structure, in particular, is based on... Figure 7As can be seen in the enlarged view, the die 32 has an annular shoulder 34 at its front end on its end face side, on which the component 6 rests with its lower side 36 during the pressing process. In the central internal region, the die 32 has a front imprinting edge 38 that protrudes against the pressing direction 12 and enters the hole 28 from the lower side 36 during the pressing process.

[0082] The embossing edge 38 has an annular surface 40 (end face) on its end face side, which transitions to the outer circumferential side 44 of the embossing edge 38 via a transition region 42, particularly with rounded corners, and then a horizontally extending annular shoulder 34 connects to this outer circumferential side. In an embodiment, the transition region 42 has a relatively large radius. Alternatively, the transition region is designed to be more angular and have a smaller radius.

[0083] In the radially inward direction, the annular edge 46, which protrudes axially against the pressing direction 12, is also connected to the annular surface 40 on the end face side.

[0084] In this embodiment, the mold 32 is solidly formed from a solid material. Alternatively, it may be hollow internally, particularly for connecting press-in bolts.

[0085] As specifically based on Figure 4 as well as Figure 5 As can be seen in the illustration, in this embodiment, the press-in nut 2 has a polygonal, particularly hexagonal, cross-sectional profile. The head 8 and the upsetting edge 20 also have this polygonal structure. Correspondingly, the hole 28 and the imprinted edge 38 also each have a corresponding polygonal structure.

[0086] When we talk about ring structures, such as ring gaps or ring upsetting edges, we mean the corresponding polygonal ring structures.

[0087] As an alternative to the polygonal structure, the upsetting edge 20 and the head 8, as well as the hole 28 and the imprinted edge 38, can be formed into a circle. A particularly high level of anti-rotation is achieved through the polygonal structure. Figure 4 The section line AA is drawn in the middle. Figure 1-3 as well as Figure 6 The sectional views respectively show at least partially the cutting planes along the section.

[0088] The special design of the press-in nut 2 in the upset edge 20 area now utilizes Figure 6 Detailed description: The base section 22 extends from the horizontally extending head support surface 16 across the base height H1 to the axial height of the step 26.

[0089] In one embodiment, step 26 extends horizontally and is therefore perpendicular to the central axis 10. Alternatively, it may slope slightly downwards outwards, in which case it forms an acute step angle relative to the horizontal plane, i.e., relative to a plane perpendicular to the pressing direction 12 or perpendicular to the central axis 10. This acute step angle is between 1° and a maximum of 20°, preferably between 3° and 8°. In the case of the inclined step 26, the axial height of step 26 is defined by the average axial height. Step 26 is typically formed of an annular surface.

[0090] The fill section 24 connects to the step 26 and extends beyond the fill height H2. In an embodiment, this fill height is approximately equal to the base height H1, and for example, 70%-90% of the base height H1. Alternatively, the fill height H2 is only 20% to 40% of the base height H1. The two heights H1 and H2 together form the total height of the upsetting edge 20. This total height preferably corresponds to the thickness (plate thickness) of the component 6. Alternatively, the total height of the upsetting edge is less than the thickness of the component 6.

[0091] In some variations, especially in the case of thin sheet metal, such as when the sheet thickness is less than or equal to 2 mm, the total height of the upsetting edge 20 in the initial state is also greater than the sheet thickness.

[0092] In other variations, particularly with thicker plates, such as those thicker than or equal to 2 mm, the total height of the upsetting edge 20 in the initial and final pressing states is less than the plate thickness, causing the lower end of the upsetting edge 20 to retract from the underside of the plate. This retraction is, for example, between 0.2 mm and 0.6 mm.

[0093] However, in the pressed state, that is, in the formed press-fit connection, the upset edge 20 does not extend beyond the underside of the component in all cases.

[0094] The base section 22 has a base thickness D1 at the midpoint of the base height H1, i.e., at a moderate base height H1. Correspondingly, the fill section 24 has a fill thickness D2 at the axial midpoint of the fill height H2, i.e., at a moderate fill height H2, which is significantly less than the base thickness D1. This fill thickness is, for example, only in the range of 10% to 30%, or alternatively only in the range of 30% to 50% of the base thickness D1.

[0095] Step 26 generally has a relatively high radial step width B1. The radial step width B1 is understood as the width of step 26 at its axial height. The upsetting edge 20 generally has a radial edge width B2 at this height. In embodiments, the step width B1 is, for example, in the range of 40% to 60% of the edge width B2, or alternatively in the range of 20% to 40%.

[0096] The base section 22 and the filling section 24, therefore, are the overall upset edge 20, which together form the base section 22. Figure 6 In the embodiment, the outer peripheral side 48 extends parallel to the central axis.

[0097] As an alternative, there is also the possibility that the circumferential side 48 will extend inwards in a generally oblique manner.

[0098] For example, the entire circumferential side 48 of the upsetting edge 20 is inclined inward toward the central axis 10, or alternatively, only the outer side 50 of the filling section 24 or the entire filling section 24 is inclined. This is used to better introduce the gap between the hole wall 30 and the imprint edge 38 of the die during processing.

[0099] According to Figure 8 and Figure 6 In different variations—from Figure 6 Starting with the variation—the entire filled section 24 slopes inward. Figure 8 In one embodiment, this causes the outer 50 of the filling section 24 to slope inwards and thus toward the central axis. Figure 8 In one embodiment, the inner side of the fill section 24, and therefore the lower inner section 54, is exemplarily oriented parallel to the central axis. However, this is not mandatory.

[0100] According to one embodiment, the upper portion of the circumferential side 48 in the base section 22 region is parallel to the central axis 10, and the lower portion of the circumferential side 48 in the filling section 24 region, thus forming the outer side 50 of the filling section 24, is oriented obliquely inward with an outer tilt angle relative to a straight line parallel to the central axis. Therefore, this outer side 50 forms an introductory slope. This outer tilt angle is preferably in the range of 5° to a maximum of 30°. When the entire outer side 50 is tilted, the outer tilt angle is preferably in the range of 10-20°, and when only the filling section 24 is tilted, it is in the range of 10-30°.

[0101] In this embodiment, the inner side of the upsetting edge 20 is designed to slope outwards. This inner side is divided into the inner side of the base section 22, referred to as the upper inner section 52, and the inner side of the filling section 24, referred to as the lower inner section 54. These two sections 52 and 54 are sloped outwards with respect to the central axis 10 at an angle α1 or a downward angle α2. These angles α1 and α2 are preferably in the range of 10° to 40°. The two angles α1 and α2 are, for example, the same, or preferably deviate from each other by a maximum of + / - 20° or a maximum of 5°.

[0102] In an alternative embodiment, the outer side 50 is inclined inward in the form of an introductory ramp, and the downward inclination angle α2 is smaller than the upward inclination angle α1 (preferably + / - a maximum of 40° or a maximum of 5°).

[0103] The two sections 52 and 54 are connected by a step 26. The transition is preferably designed with rounded corners.

[0104] Against the pressing direction 12, the upper wall section 56, which is set slightly steeper, connects to the upper inner section 52. This upper wall section is part of the intermediate section between the upsetting edge 20 and the start of the internal thread 14.

[0105] The internal thread 14 is axially spaced from the upsetting edge 20. This axial distance is, for example, between 0.5 and 1.5 times the base height H1. This measure generally prevents deformation of the thread 14 during the forming process. This reliably ensures the dimensional stability of the thread 14 after pressing.

[0106] The press-fit connection 4 is preferably formed as follows:

[0107] In the first step, the mold 32 is introduced into the hole 28 from below until the part 6 rests on the annular shoulder 34 with its lower side 36. This situation occurs in Figure 1 And especially Figure 7 As shown in the diagram, the press-in nut 2 is also located outside the hole 28.

[0108] Subsequently, the press-in nut 2 is displaced in the press-in direction 12, so that the upset edge 20 is first introduced into the hole 28. Figure 2 ) and is pressed against the die, particularly against the imprint edge 38, until the head support surface 16 rests on the upper side 18 of the component 6. Figure 3 ).

[0109] Using the press-in nut 2 described here, it is also possible in principle to first insert the press-in nut 2 into the hole 28 with the upsetting edge 20 until the head support surface 16 rests on the upper side 18, and then introduce the die from below and press it against the upsetting edge 20 to shape it.

[0110] However, the particular advantage of press-fit nut 2 is reflected in the aforementioned method, in which the die 32 is first introduced into the hole 28.

[0111] In any case, the dimensions are chosen such that an annular gap 58 (annular clearance) is formed between the upsetting edge 38, particularly its circumferential side 44, and the hole wall 30. The radial outer dimension of the upsetting edge 20, and therefore its circumferential side 48, is also sized such that a gap is maintained toward the hole wall 30. The gap dimension s of the gap 58 between the circumferential side 44 of the upsetting edge 38 and the hole wall 30 is preferably 0.1 mm to 0.6 mm, or particularly up to 1 mm in the case of larger dimensions (e.g., greater than M10). Preferably, in the undeformed initial state, the upsetting edge 20 has the same gap dimension as the hole wall 30, or alternatively even slightly higher, for example, up to 20%.

[0112] Typically, the filling section 24 has a radially outer dimension at its front end, which is adapted to the radially outer dimension of the imprinting edge 38 such that the filling section 24 is supported on the transition region 42 of the imprinting edge 38 with its front end. The annular surface 40 of the end face of the imprinting edge 38 then reaches the step 26 and preferably applies only axial force to it, causing the desired volumetric forming, and the material of the base section 22 is radially displaced outward by flow. Through flow, the material is first displaced radially and pressed against the bore wall 30. Subsequently, the axial force component also comes into play, causing the material of the filling section 24—which has simultaneously entered the annular void 58—to also experience the axial force component, thus being further pressed into the annular void 58, filling the void by material flow, and generally also pressed radially against the bore wall 30.

[0113] By arranging the relatively thin filling section 24 on its end face side—which has entered the annular void 58 before actual volume deformation—material filling of the annular void 58 is reliably ensured, in particular, that the material is pressed against the hole wall 30, preferably along the entire length of the hole wall 30, even in the described process case, where the imprinted edge 38 is first inserted into the hole 28.

[0114] Thus, a press-fit connection 4 is formed in a generally reliable and trustworthy manner, exhibiting high pull-out resistance and good anti-rotation properties. Furthermore, the press-fit connection 4 is typically watertight.

[0115] The hole wall 30 is specifically formed by a stamping operation, causing it to widen slightly towards the lower side 36, and is particularly torn or broken, forming a fracture surface 60. The lower side 36 is also the lower side during the stamping process, i.e., in this case, the stamping tool is driven through the part 6 from above, from the upper side 18, in the pressing direction 12 towards the lower side 36. The fracture surface 60 is... Figure 7 The details are exaggerated for illustrative purposes. The fracture surface 60 is typically oriented at a fracture surface angle β relative to the central axis 10. The axial height here typically extends to a maximum of more than 2 / 3 of the thickness of component 6.

[0116] The material of the upset edge 20, particularly the filling section 24, is pressed into the radially widened portion of the hole 30 formed by the fracture surface 60. Therefore, axial pull-out protection is decisively influenced and ensured by the special design of the filling section 24.

[0117] Through the above-mentioned stamping process, the hole wall 30 is also frequently deformed in the area of ​​the upper side 18, which causes the hole wall 30 to shrink at the upper side 18.

[0118] In some applications, there is a requirement that the punching process and the pressing of the nut 2 are carried out from different directions, that is, the punching process is carried out from the upper side 18 to the lower side 36, while the pressing of the nut 2 is inserted from the lower side 36 of the component 6 to the upper side 18.

[0119] Even in this process variant—where the stamping and pressing operations are performed in opposite directions—material pressing of the (slightly) enlarged hole wall 30 in the region of the upper side 18 is achieved through the filling section 24, thus also achieving axial pull-out prevention in this case.

[0120] List of reference numerals

[0121] 2. Press in the nut

[0122] 4. Press-in connection

[0123] 6 components

[0124] 8. Head

[0125] 10. Central Axis

[0126] 12 Pressing direction

[0127] 14 Internal Thread

[0128] 16 Head support surface

[0129] 18 upper side

[0130] 20 Upsetting edge

[0131] 22 Base Section

[0132] 24 Filling Section

[0133] 26 steps

[0134] 28 holes

[0135] 30-hole wall

[0136] 32 Pressing mold

[0137] 34. Circular shoulder

[0138] 36 Lower side

[0139] 38 Embossing edge

[0140] 40 Annular surface

[0141] 42 Transition Zone

[0142] 44. Circumferential side of the embossed edge

[0143] 46. ​​Circular edge

[0144] 48 Upsetting edge 20 circumferential side

[0145] 50. Outer side of the filled section

[0146] 52 Upper inner section

[0147] 54 Lower inner section

[0148] 56 Upper Wall Section

[0149] 58 Annular gap

[0150] 60 Fracture surface

[0151] H1 Base Height

[0152] H2 Fill Height

[0153] D1 Base thickness

[0154] D2 Fill Thickness

[0155] B1 Radial Step Width

[0156] B2 Radial side width

[0157] The upward tilt angle of the inner segment of α1

[0158] α2 Downsloping angle of the inner segment

[0159] β Fracture surface angle

[0160] s gap size

Claims

1. A press-fit element (2), particularly a press-fit nut (2), for forming a press-fit connection (4) with a pre-drilled component (6), wherein the press-fit element (2) Extending along the central axis (10) in the pressing direction (12), A head (8) with a head support surface (16) is provided for resting on the component (6). It has an upsetting edge (20) connected to the head (8) in the pressing direction (12), the upsetting edge being designed to be threadless. Its features are, The upsetting edge (20) has a base section (22) and a filling section (24), wherein the filling section (24) is connected to the base section (22) in the case of forming an inner step (26) oriented toward the central axis (10), wherein the base section (22) has an axial base height (H1) extending from the head support surface (16) to the step (26), and the filling section (24) has an axial filling height (H2) extending from the step (26) to the front end of the upsetting edge (20) in the pressing direction (12).

2. The press-fit element (2) according to the preceding claim, characterized in that, The fill height (H2) is in the range of 20% to 100% of the base height (H1), especially in the range of 30% to 60% of the base height (H1).

3. The press-fit element (2) according to any one of the preceding claims, characterized in that, The base section (22) has a base thickness (D1) at half the base height (H1), the fill section (24) has a fill thickness (D2) at half the fill height (H2), and the fill thickness (D2) is in the range of 5% to 40% of the base thickness (D1), particularly in the range of 10% to 30% of the base thickness (D1).

4. The press-in element (2) according to any one of the preceding claims, characterized in that, The step (26) has a radial step width (B1), the upsetting edge (20) has a radial edge width (B2) at the height of the step (26), and the radial step width (B1) is in the range of 20% to 80% of the radial edge width (B2), particularly in the range of 30% to 60% of the radial edge width (B2).

5. The press-fit element (2) according to any one of the preceding claims, characterized in that, The base section (22) and the filling section (24) transition to each other without steps on the outer side.

6. The press-fit element (2) according to any one of the preceding claims, characterized in that, The base section (22) and the filling section (24) form a common circumferential side (48) extending parallel to the central axis (10).

7. The press-fit element (2) according to any one of claims 1 to 5, characterized in that, The outer side (50) of the filling section (24) is inclined inward toward the central axis (10), preferably with an outer inclination angle in the range of 5° to 30°.

8. The press-fit element (2) according to any one of the preceding claims, characterized in that, The inner side of the filling section (24), referred to as the lower inner section (54), is preferably inclined outward at a lower angle (α2) relative to the pressing direction (12), wherein the lower angle (α2) is particularly in the range of 10° to 40°, particularly between 15° and 30°.

9. The press-fit element (2) according to any one of the preceding claims, characterized in that, The inner side of the base section (22), referred to as the upper inner section (52), is inclined outward at an angle (α1) above the pressing direction (12), wherein the upper inclination angle (α1) is particularly in the range of 10° to 40°, and particularly in the range of 15° to 30°.

10. The press-fit element (2) according to the preceding claim, characterized in that, An upper wall section (56) is connected to the upper inner section (52) in the opposite direction of pressing (12). This upper wall section extends steeper than the upper inner section (52), preferably until it becomes cylindrical.

11. The press-fit element (2) according to any one of the preceding claims, characterized in that, The upset edge (20) has a polygonal, in particular hexagonal, outer contour (48).

12. A method for creating a press-fit connection (4) between a press-fit element (2) according to any one of the preceding claims and a pre-drilled part (6) having a hole (28) with a circumferential hole wall (30), wherein the press-fit element (2) enters the hole (28) with its upset edge (20) and the upset edge (20) is formed by means of a die (32) having a front stamped edge (38) such that the edge material is pressed against the hole wall (30), in particular without the lower side (36) of the part (6) being held against the rear by the upset edge (20).

13. The method according to the preceding claim, wherein the filling section (24) enters the annular gap (58) between the circumferential side (44) of the front embossed edge (38) and the hole wall (30).

14. The method according to any one of the preceding two claims, wherein the component (6) is first placed on the die (32) and the front stamping edge (38) enters the hole (28), and then the press-in element (2) is pressed against the die (32) from above.

15. The method according to any one of claims 12 to 14, wherein the front stamping edge (38) has a radially extending end face (40) pressed against the step (26).

16. The method according to the preceding claim, wherein the end face (40) transitions to the circumferential side (44) of the front stamping edge (38) through a rounded or chamfered transition region (42), and preferably there is an annular gap (58) between the circumferential side (44) and the hole wall (30) at the start of the stamping process.

17. The method according to any one of the preceding two claims, wherein the end face (40) acts against the step (26) in the reverse pressing direction (12) and presses it into the circumferential annular gap (58) between the front stamping edge (38) and the hole wall (30) by volume forming of the edge material.

18. The method according to any one of claims 15 to 17, wherein the end face is designed as an annular surface (40), the annular surface being defined by an annular edge (46) in the inward direction toward the central axis (10), the annular edge preventing the edge material from displacing inward toward the central axis (10).

19. A press-fit connection (4) having a press-fit element (2) according to any one of claims 1 to 11, particularly produced by the method according to any one of claims 12 to 18.

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