Fastener

Abstract

Fastening element (1), in particular mounting bolt, comprising a fixing section (10), an intermediate section (20) and a fitting section (30), wherein the fastening element (1) extends along a longitudinal axis (L), wherein the fixing section (10) has fixing structures, namely a thread, wherein the intermediate section (20) is arranged in the direction of the longitudinal axis (L) between the fixing section (10) and the fitting section (30), wherein the fitting section (30) is essentially rotationally symmetric about the longitudinal axis (L), wherein the fitting section (30) has an outer bearing surface (34), wherein the bearing surface (34) has a clearance fit, and wherein at least one lubrication groove (32) is present in the fitting section (30), wherein the cross-section of the lubrication groove (32) has an opening (36) pointing in a radial direction (R) and a bottom section (38), where the bottom section (38) is in particular rounded, wherein the opening (36) has a smaller extent in the direction of the longitudinal axis (L) than the bottom section (38), wherein the fitting section (30) has 3 - 20 lubrication grooves (32) which are designed as lubrication helices.

Description

[0001] The invention relates to a fastening element, in particular a clearance-fit fastening element.

[0002] Fasteners are already known from the prior art. These elements serve to connect two components in such a way that forces can be transferred from one component to the other. Often, these fasteners are designed so that the components being fastened are movable relative to each other. This is achieved in particular by providing a clearance fit between the component being fastened and the fastener. However, it is common – especially with precise guidance of the component being fastened – for a certain degree of resistance to movement to occur between the components being fastened and the fastener, particularly due to corrosion and / or friction.

[0003] DE 102 03 133 C1 relates to a fastening device for a mounting bolt, a point holder for a building plate, wherein the mounting bolt engages in the point holder with a ball head and wherein the fastening device has a first and a second threaded section.

[0004] WO 2006 / 096108 A1 relates to a connecting element for joining mechanical parts, wherein the connecting element has an integrated cutting surface.

[0005] EP 1 126 191 A2 relates to a guide element that enables an associated mechanical part to be held slidably and centered. The guide element comprises a shaft extending along a longitudinal axis. A circumferential section of an outer surface of the shaft is provided with helical grooves, the ridges formed between each adjacent pair of turns of the grooves having a flat surface that runs substantially parallel to the axis of the shaft.

[0006] FR 2 771 149 A1 relates to a column for guiding a brake caliper for a disc brake. The column comprises a cylindrical body with helical grooves along its length. The end of the column screwed into the bracket terminates in a conical section that fits into a conical bore in the bracket, and a threaded end that screws into a threaded hole in the bracket.

[0007] The object of the invention is therefore to provide a fastening option that enables smooth operation.

[0008] This problem is solved with a mounting element according to claim 1 and with a mounting system according to claim 7.

[0009] According to the invention, a fastening element, in particular a mounting bolt, comprises a fixing section, an intermediate section and a fitting section, wherein the fastening element extends along a longitudinal axis, wherein the fixing section has fixing structures, namely a thread, wherein the intermediate section is arranged in the direction of the longitudinal axis between the fixing section and the fitting section, wherein the fitting section is substantially rotationally symmetric about the longitudinal axis, and wherein the fitting section has an outer bearing surface, wherein the bearing surface has a clearance fit, and wherein at least one lubrication groove is present at least in the fitting section.The fastening element according to the invention serves in particular to connect a mounting part with a fixing part in such a way that these are movable relative to each other along the longitudinal axis, while the fastening element can absorb or transmit forces perpendicular to this longitudinal axis or axis of movement. In other words, the fastening element according to the invention can serve to enable a fastening in which movement – ​​at least to a certain extent – ​​is possible between the parts to be fastened (mounting part and fixing part) in the direction of the longitudinal axis of the fastening element. The longitudinal axis of the fastening element is the axis along which the fastening element primarily extends. In other words, the longitudinal axis is in particular the axis along which the length of the fastening element is determined.The fastening element comprises at least one fixing section, an intermediate section, and a fitting section. The fixing section serves to connect the fastening element to a fixing part, e.g., by means of a positive fit. Advantageously, this connection is such that no relative movement is possible between the fixing part and the fixing section of the fastening element when installed. To achieve this fixing, the fixing section has, in particular, fixing features. These fixing features can, for example, be formed by an external thread. Alternatively, or preferably, these fixing features can also be formed by an internal thread. However, fixing features generally include any features that enable the fixing section of the fastening element to be firmly connected to a fixing part.For example, such a fixing structure can also be created by a forming process, such as by crimping parts of the fixing section. Between the fixing section and the fitting section – viewed along the longitudinal axis – lies the intermediate section of the fastening element. Advantageously, the intermediate section is at least partially rotationally symmetrical about the longitudinal axis. For example, the intermediate section can be at least partially conical and / or cylindrical to create a change in geometry along the longitudinal axis. This can, for instance, serve to enable a smooth transition of the external dimensions between the fixing section and the fitting section, resulting in a mechanically robust fastening element. In particular, the intermediate section is designed to taper from the fixing section to the fitting section.This design takes into account the predominantly occurring bending stress distribution along the longitudinal axes, thus saving material while simultaneously ensuring sufficient bending stiffness and strength of the fastener. The fitting section of the fastener serves primarily to interact directly or indirectly with a mounting component. This fitting section is designed to have an outer bearing surface intended for direct or indirect contact with the mounting component. To allow movement along the longitudinal axis between the fastener and the mounting component, the bearing surface is designed to provide a clearance fit, particularly in relation to the surfaces of the mounting component that surround and / or can contact the fitting section of the fastener in its installed state.For example, the fit of the mating section can be designed such that it falls within tolerance classes IT4 to IT11 according to DIN ISO 286-1. The mating section is essentially rotationally symmetrical about its longitudinal axis. "Essentially rotationally symmetrical" means that the basic shape of the mating section, in particular its bearing surface(s), is rotationally symmetrical about its longitudinal axis, for example, at least partially conical, cylindrical, trilobular, or five-lobular. The mating section is considered essentially rotationally symmetrical if its bearing surface is calibrated as trilobular and has an outside diameter tolerance of ≤ 30 µm and a trilobularity of 10 µm to 100 µm.Alternatively, preferably, or additionally, the fitting section may also be substantially rotationally symmetric if the bearing surface(s) of the fitting section has a five-lobular calibrated bearing surface with an outside diameter tolerance of ≤ 30 µm and a defined out-of-roundness of 10 µm to 100 µm. However, this fundamental rotational symmetry of the fitting section, in particular the bearing surface(s) of the fitting section, may be disrupted, in particular by lubrication grooves or depressions converging on the lubrication grooves, without violating the principle of a "substantially rotationally symmetric" fitting section.In other words, this can mean that the fitting section can be fundamentally cylindrical, conical, or barrel-shaped, and that, for example, one or more lubrication grooves or helixes can be incorporated into this ideal rotationally symmetrical shape around the longitudinal axis without disrupting the essentially rotationally symmetrical shape of the fitting section. In the fitting section according to the invention, one or more lubrication grooves are incorporated into the bearing surface, which, as already explained, can disrupt the rotationally symmetrical design of the fitting section. The lubrication groove(s) serve to receive lubricants and enable the introduction of lubricant into the contacting area of ​​the fitting section, in particular onto the bearing surface.This achieves a reduction in friction, enabling the fastening element according to the invention to be easily installed between the fastening element and the mounting part. Additionally, this can prevent or hinder corrosion, particularly that caused by fit issues, over the long term, thus maintaining a smooth fit even over extended periods. The lubrication groove(s) in the fitting section can be rotationally symmetrical about the longitudinal axis. This is possible, for example, with a closed, ring-shaped design of the lubrication grooves. Alternatively, and preferably, the lubrication groove(s) can also be designed such that they completely penetrate the fitting section in the direction of the longitudinal axis or extend completely through / over the fitting section in the longitudinal direction.This can be the case, for example, if the lubrication grooves extend along the longitudinal axis across the entire mating section. This can be achieved, for instance, by a straight lubrication groove. Extending the lubrication groove, or at least some of the lubrication grooves, along the entire mating section in the direction of the longitudinal axis allows for the external application of lubricant even during assembly. Furthermore, or alternatively, this can also ensure reliable lubrication of the entire mating section in the direction of the longitudinal axis.

[0010] According to the invention, at least one lubrication groove, and in particular all lubrication grooves, is a lubrication helix. A lubrication helix is ​​understood to be a groove that is helically formed within the mating section. In other words, the lubrication helix can be designed similarly to a thread. By providing at least one lubrication helix, a particularly homogeneous and effective distribution of the lubricant is achieved – both along the longitudinal and circumferential directions.

[0011] According to the invention, the fitting section has a plurality of lubricating coils, with the fitting section in particular having 3 to 20 lubricating coils. Providing a plurality of lubricating coils allows for a particularly simple distribution of the lubricant, especially since the pitch of the lubricant can be chosen to be particularly large. This allows the length of the individual lubricating coils to be reduced, so that even highly viscous lubricants can be efficiently introduced into the coil. The fitting section preferably has 3 to 20 lubricating coils. This allows for a particularly simple supply of lubricant. In other words, providing 3 to 20 lubricating coils ensures that even after commissioning or...After the fastener is installed, lubricant can easily be introduced into the clearance gap between the bearing surface and the mounting part. This allows for lubricant replenishment, particularly without disassembling the fastener.

[0012] Advantageously, the bearing surface is cylindrical around its longitudinal axis. A bearing surface is cylindrical, in particular, when it is entirely situated between two imaginary cylinders with a diameter difference of 30 to a maximum of 100 µm, and where, in particular, the axis of symmetry of these two imaginary cylinders lies on the longitudinal axis. The cylindrical design of the bearing surface results in a particularly homogeneous stress distribution, enabling the fastening element to reliably withstand high lateral forces. This cylindrical design of the bearing surface can advantageously be achieved by calibrating the raw profile in a subsequent manufacturing step, especially by rolling.

[0013] According to the invention, the cross-section of the lubrication groove has a radially oriented opening and a bottom section, the bottom section being particularly rounded. The relevant cross-section for this determination is the cross-section of the lubrication groove perpendicular to the direction of the lubrication groove. The opening of the lubrication groove is particularly designed to create a contour on the bearing surfaces. In other words, this can mean that the opening forms the radially outwardly oriented ends of the lubrication groove. The radial direction is the direction that points radially away from the longitudinal axis. The bottom section of the lubrication groove is the section of the groove that connects the two flanks of the lubrication groove. The bottom section is particularly rounded.This rounded bottom section results in particularly simple manufacturing of the bottom section and, moreover, allows for a particularly low notch effect and consequently a particularly high degree of strength. Advantageously, the ratio of the rounded bottom section's diameter to the outer diameter of the bearing surface of the mating section is in the range of 0.025 to 0.05. This design results in a thread that is particularly mechanically strong and exhibits minimal notch effect. In particular, the rounding of the bottom section is designed such that it is larger than that of a comparable metric thread.

[0014] In a further development according to the invention, the opening, particularly in the direction of the longitudinal axis, has a smaller extent than the base section. In other words, this can mean that the lubrication groove is designed such that it tapers towards the opening. Therefore, the lubrication groove can be designed such that, in particular, those parts of the groove between the base section and the opening taper towards the opening. This tapering allows for controlled lubricant release. In particular, this tapered section retains some of the lubricant, thus achieving a particularly homogeneous lubricant release along the entire length of the lubrication groove.

[0015] In a preferred embodiment, the cross-section of the lubrication groove has an arrow-shaped connecting section, wherein the arrow-shaped connecting section tapers in the radial direction. The connecting section is the part or parts of the cross-section of the lubrication groove that connect the bottom section to the opening. In particular, the cross-section is straight in this connecting area. The term "arrow-shaped" here means that, theoretically, the two connecting sections, which are preferably leg-shaped, are designed such that these parts or legs of the connecting section would theoretically intersect outside the fastening element.In other words, the connecting section can be at least partially V-shaped, with the (imaginary) intersection of the two V-shaped legs located radially outside the fastening element. This type of connecting section design is particularly easy to manufacture, resulting in a cost-effective fastening element.

[0016] In a preferred embodiment, the opening angle of the arrow-shaped connecting section is in the range of 10° to 70°, preferably in the range of 20° to 60°, and particularly preferably in the range of 30° to 50°. The opening angle is the angle formed between the arrow-shaped legs of the connecting section. With an opening angle in the range of 10° to 70°, a particularly easy-to-manufacture lubrication groove results, leading to a cost-effective fastening element. With an opening angle in the range of 20° to 60°, a particularly homogeneous lubricant distribution can be achieved, because even highly viscous lubricants can, with such a design, enter or be introduced homogeneously along the length of the lubrication groove in a radial direction outwards through the opening into the gap to be lubricated.With an opening angle in the range of 30° to 50°, the cross-section of the lubrication groove has a particularly low notch effect, resulting in a particularly high mechanical strength of the fastening element.

[0017] Preferably, the ratio of the minimum diameter of the lubrication groove, particularly its bottom section, to the diameter of the bearing surface is in the range of 0.8 to 0.98, more preferably in the range of 0.85 to 0.95, and most preferably in the range of 0.88 to 0.92. The minimum diameter of the lubrication groove is determined in particular by those parts or areas of the lubrication groove that are closest to the longitudinal axis. This is especially the bottom section of the lubrication groove. For determining the ratio, the diameter of the bearing surface is in particular the mean diameter of the bearing surface along the longitudinal axis of the mating section. A diameter ratio in the range of 0.8 to 0.98 results in a particularly high degree of homogeneity of the lubricant within the lubrication groove and within the gap to be lubricated.In other words, this ratio allows for a particularly large amount of lubricant to be absorbed, resulting in a particularly long lubrication service life. A diameter ratio in the range of 0.85 to 0.95 results in a fitting section with a particularly low notch effect. This is crucial because high notch effects, especially under bending loads, have a significant impact on the mechanical strength of the fastener. Therefore, a diameter ratio of 0.85 to 0.95 results in a fastener with particularly high mechanical strength. A diameter ratio in the range of 0.88 to 0.92 results in a fitting section that is particularly easy to manufacture, especially through cold forming. This allows for a particularly cost-effective fastener.

[0018] Advantageously, the bearing surface area of ​​the mating section is in the range of 0.3 to 0.8, preferably in the range of 0.4 to 0.7, and particularly preferably in the range of 0.5 to 0.65. The bearing surface area of ​​the mating section is that part which is attributable to the bearing surface. For example, this area can be determined by subtracting from the total surface area of ​​the mating section the portions of the surface formed by the lubrication groove or by the opening of the lubrication groove. In other words, the bearing surface area can be determined by projecting the lubrication grooves and the bearing surfaces onto a cylinder directly surrounding the mating section and then determining the portion of the cylinder's surface that is formed or covered by the projection of the bearing surface.With a bearing surface area of ​​0.3 to 0.8, a particularly high load-bearing capacity of the fastener or the fitting section can be achieved, as this allows the bearing surface to absorb a particularly high degree of forces and moments. A bearing surface area of ​​0.4 to 0.7 results in a bearing surface that is particularly easy to manufacture. With a bearing surface area of ​​0.5 to 0.65, particularly good lubrication can be achieved, as a large portion of the fitting section is formed by lubricating grooves in this design.

[0019] Preferably, a lubricant, in particular a grease or oil, is present or introduced into at least one lubrication groove. Providing a lubricant allows for particularly simple lubrication.

[0020] Advantageously, the fastener is manufactured by cold forming. Manufacturing the fastener using cold forming has a positive effect on the material, as cold forming leads to a mechanical hardening of the material, making a cold-formed fastener significantly more mechanically resistant compared to one that has not been cold-formed.

[0021] Advantageously, the fitting section forms an end section, particularly in the direction of the longitudinal axis of the fastening element. Forming the fitting section as an end section allows for particularly simple manufacturing of the fastening element. An end section is understood to mean that the fitting section forms the last distal area of ​​the fastening element, especially in the direction of the longitudinal axis.

[0022] Alternatively, preferably, a stop section can also extend behind the fitting section in the direction of the longitudinal axis. By providing a stop section, it is possible to positively prevent any relative movement in the direction of the longitudinal axis between the fastening element and the mounting part. For example, such a stop section can be formed by a radially projecting stop. Advantageously, this radially projecting extension (stop section) extends in a ring shape around the longitudinal axis.

[0023] Preferably, the fixing section has fixing features in the form of an internal and / or external thread. Providing an internal and / or external thread allows for particularly easy assembly. Alternatively, or additionally preferably, the fixing section can also have a tool engagement contour, such as an external hexagon, an internal hexagon, or an internal Torx. This further simplifies the assembly of the fastener, as the tool engagement contour eliminates the need for additional clamping tools.

[0024] Advantageously, the fixing section forms an end section, particularly along the longitudinal axis of the fastener. By locating the fixing section as an end section, a particularly simple geometry is achieved, because areas located in the end sections can be more easily machined with a high degree of deformation, especially during forming. Therefore, by placing the fixing section in an end region or end section of the fastener, a fastener that is particularly easy and cost-effective to manufacture is produced.

[0025] Another aspect of the invention relates to a mounting system comprising a fastening element, in particular a fastening element as described above and below, and a mounting part, wherein the mounting part has a receptacle, wherein the fastening element has a fitting section, the fitting section extending at least partially into the receptacle or being designed to extend at least partially into the receptacle, wherein the receptacle and the fitting section have a clearance fit relative to each other. In other words, the mounting element can have the properties and features of the fastening element described above, particularly with regard to the fitting section. Alternatively, and preferably, the fastening element can also be designed such that no lubrication grooves are present in the fitting section.In such a design, it is at least advantageous according to the invention if the mounting part has a lubrication groove. This lubrication groove of the mounting part can be designed such that it possesses the properties and features of the lubrication groove of the fastening element described above. In other words, this can mean that the properties and features of the lubrication groove described in this document can also be implemented in the lubrication groove of the mounting part. It is particularly preferred if both the fastening element and the mounting part have a lubrication groove in the form of a lubrication helix, provided that these two helixes are designed to run in opposite directions. This prevents the lubrication helixes of the fastening element from interlocking with the lubrication helixes of the mounting part.The receiving area of ​​the mounting part is, in particular, a recess which is advantageously designed to be complementary to the outer contour of the fitting section of the fastening element. These sections, which are designed in opposition to each other, are in particular designed as a clearance fit. In other words, this can mean that the fastening element, with its fitting section, can theoretically be inserted into the receiving area of ​​the mounting part without contact. The mounting system according to the invention, through the lubrication grooves – in the mounting part, in particular in its receiving area, and / or in the fitting section of the fastening element – ​​efficiently achieves lubrication and thus a reduction of friction in the gap between the mounting part and the fastening element.

[0026] Another example concerns a manufacturing process for a fastener, particularly according to one of the preceding embodiments, wherein the fastener has a mating section with a lubrication groove and a bearing surface, and wherein the manufacturing process comprises the steps of: providing a blank; machining the blank, particularly by cold forming, whereby the machining or cold forming specifically creates the lubrication groove. The manufacturing process can specifically include the steps of machining the blank to create the mating section – with the lubrication groove – and the bearing surface. This exemplary manufacturing process allows for the cost-effective production of a fastener. Machining the blank by cold forming results in a particularly mechanically robust fastener.The cold forming of the blank is carried out, in particular, by moving a die and a punch relative to each other in the direction of the longitudinal axis of the fastener during the manufacturing process. The cold forming of the blank can be performed either in a single operation or in several, sequential cold forming operations. Advantageously, the fixing structures or structures of the fixing section, namely threads, are produced directly during the cold forming. This results in particularly cost-effective manufacturing of the fastener. Alternatively, and preferably, the thread (or threads) is produced in a separate, subsequent rolling operation. This allows for particularly precise thread manufacturing.

[0027] Preferably, especially after cold forming, the bearing surface of the mating section is calibrated, particularly by rolling. This calibration of the bearing surface allows for a particularly flat or cylindrical bearing surface to be achieved. Additionally, this calibration preferably also reduces the openings of the lubrication grooves. This, among other things, makes it more difficult for the lubricant to escape from the lubrication groove. Advantageously, this calibration is carried out by rolling, as this allows for a particularly cost-effective calibration with very tight tolerance classes, especially IT4 to IT7. Advantageously, this calibration step is performed after the forming or cold forming of the workpiece blank and can therefore be considered a type of finishing process.

[0028] Further advantages and features of the present invention will become apparent from the following description with reference to the figures. Individual features of the illustrated embodiment can also be used in other embodiments, unless this has been expressly excluded. The figures show: Fig. 1 - A section through a mounting system with a fastener; Fig. 2 - A detailed view of part of a fastener; Fig. 3 - A detailed view of a section through part of the fitting section; and Fig. 4 - Another detailed view of a section through a fitting section of a fastener. Fig. 5 - Another detailed view of part of a fastener

[0029] In the Fig. Figure 1 shows a mounting system comprising a fastening element 1, a mounting part 100, and a fixing part 200. The fixing part 200 is indirectly and rigidly connected to the fixing section 10 of the fastening element 1. For this purpose, the fixing section 10 has fixing structures in the form of an internal thread. The fastening element 1 extends along the longitudinal axis L, with the fixing section 10 and the fitting section 30 each forming end sections of the fastening element 1 in the direction of the longitudinal axis L. The intermediate section 20 of the fastening element 1 extends between the fixing section 10 and the fitting section 30. The fitting section 30 of the fastening element 1 has a lubrication groove 32, which is designed in the form of a lubrication helix and extends spirally around the longitudinal axis L on the outside of the fitting section 30. Between the individual lubrication grooves 32 and 30, respectively, there is a lubricating groove 32.The bearing surface 34 is located in the space between two adjacent portions of the lubrication groove 32. This surface serves to make direct contact with the receptacle 110 of the mounting part 100. By providing the lubrication groove 32 in the mating section 30 of the fastening element 1, lubricant can be efficiently introduced into the gap between the receptacle 110 and the mating section 30. To allow relative movement between the mating section 30 and the receptacle 110, both the mating section 30 and the receptacle 110 have a clearance fit.

[0030] In the Fig. Figure 2 shows a detailed view of part of the fastening element 1. In principle, the [element] in the Fig. 2 Detail section of the fastening element 1 shown in the Fig. The fastening element shown in section 1 fits. Fig. Figure 2 shows that the fastening element 1 has both an intermediate section 20 and a fitting section 30. The fastening element 1 primarily extends along the longitudinal axis L, with the radial direction R extending radially to this longitudinal axis L. The bearing surface 34 is located on the outer surface of the fitting section 30 in the direction of the radial direction R. This bearing surface serves to absorb forces and transmit loads or mechanical forces between the fastening element 1 and a mounting part 100. As can be seen from the Fig. As can be seen in Figure 2, a lubrication groove 32 extends on the outer surface of the fitting section 30. In principle, not only one lubrication groove 32 can be provided, but a plurality of lubrication grooves 32. For example, these lubrication grooves 32 can be designed as lubrication helixes 32 or as lubrication rings 32.

[0031] In the Fig. Figure 3 shows a detailed view of a section through the fitting section 30. As can be seen from the Fig. As can be seen in Figure 3, a bearing surface 34 extends between each pair of lubrication grooves 32, particularly in the longitudinal direction L. These lubrication grooves 32 have a bottom section 38. In the case of the Fig. In the situation shown in Figure 3, the profile of the support surface 34 is arc-shaped. For example, such a design results particularly when the support surface 34 is not calibrated.

[0032] In the Fig. Figure 4 also shows a detailed view of a section of a fitting section 30. In the Fig. In the situation shown in Figure 4, the fastener 1 has a bearing surface 34 calibrated by rolling. For example, as in the Fig. 4. Situation depicted by a calibration of the in the Fig. 3 situations are achievable. As can be seen from the comparison of the Fig. 3 and the Fig. As can be seen in Figure 4, this calibration can achieve a significant change in the design of the lubrication grooves 32 and the bearing surface 34. The lubrication groove 32 is located in the Fig. The embodiment shown in Figure 4 is designed such that it has a rounded bottom section 38 to which the connecting sections 40 are attached, which are arrow-shaped and taper radially in the direction R. These connecting sections 40 have an opening angle W1 to each other. The lubrication groove 32 is formed by the opening 36 in the radial direction R. As can be seen from the Fig. As can be seen in Figure 4, the opening 36 in the direction of the longitudinal axis L has a smaller extent than the bottom section 38 of the lubrication groove 32. This tapered design of the lubrication groove 32 in the radial direction R prevents or at least reduces uncontrolled lubricant leakage from the lubrication groove 32.

[0033] In the Fig. Figure 5 shows an external view of the fitting section 30. As can be seen from the Fig. As can be seen in Figure 5, a bearing surface 34 extends between each pair of lubrication grooves 32, particularly in the longitudinal direction L. These lubrication grooves 32 have a bottom section 38. In the case of the Fig.In the situation shown in Figure 5, the bearing surface 34 between two lubrication grooves 32 is spiral in shape, because the lubrication grooves 32 themselves are designed as lubrication helices 32. In the fitting section 30, there are a multitude of lubrication helices 32, which are designed around the longitudinal direction L similarly to a multi-start thread. Reference symbol list: 1 fastening element 10. Determination section 20 Intermediate section 30 Fitting section 32 lubrication groove 34 Support surface 36 Opening 38 Floor section 40 Connecting section 100 mounting parts 110 recording 200 Determination section L Longitudinal axis R Radial direction W1 Opening angle

Claims

[1] Fastening element (1), in particular mounting bolt, comprising a fixing section (10), an intermediate section (20) and a fitting section (30), wherein the fastening element (1) extends along a longitudinal axis (L), wherein the fixing section (10) has fixing structures, namely a thread, wherein the intermediate section (20) is arranged in the direction of the longitudinal axis (L) between the fixing section (10) and the fitting section (30), wherein the fitting section (30) is essentially rotationally symmetric about the longitudinal axis (L), wherein the fitting section (30) has an outer bearing surface (34), wherein the bearing surface (34) has a clearance fit, and wherein at least one lubrication groove (32) is present in the fitting section (30), wherein the cross-section of the lubrication groove (32) has an opening (36) pointing in a radial direction (R) and a bottom section (38), where the bottom section (38) is in particular rounded, wherein the opening (36) has a smaller extent in the direction of the longitudinal axis (L) than the bottom section (38), wherein the fitting section (30) has 3 - 20 lubrication grooves (32) which are designed as lubrication helices. [2] Fastening element (1) according to one of the preceding claims, wherein the bearing surface (34) is cylindrical around the longitudinal axis (L). [3] Fastening element (1) according to one of the preceding claims, wherein the ratio of the minimum diameter of the lubrication groove (32), in particular its bottom section (38), to the diameter of the bearing surface (34) is in a range of 0.80 to 0.98, preferably in a range of 0.85 to 0.95 and particularly preferably in a range of 0.88 to 0.

92. [4] Fastening element (1) according to one of the preceding claims, wherein the bearing surface area of ​​the fitting section (30) is in a range of 0.3 to 0.8, preferably in a range of 0.4 to 0.7 and particularly preferably in a range of 0.5 to 0.

65. [5] Fastening element (1) according to one of the preceding claims, wherein the fastening element (1) is a cold-formed fastening element (1). [6] Fastening element (1) according to claim 5, wherein the bearing surface (34) of the fitting section (30) is a rolled bearing surface (34). [7] Mounting system comprising a fastening element (1) according to one of the preceding claims and a mounting part (100), wherein the mounting part (100) has a receptacle (110), wherein the fastening element (1) has a fitting section (30), wherein the fitting section (30) extends at least partially into the receptacle (110) or is designed to extend at least partially into the receptacle (110), where the inlet (110) and the fitting section (30) have a playing fit to each other.

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