DE102020129387A1 - Screw connection system and method for producing a screw connection using a screw connection system - Google Patents

Abstract

The invention relates to a screw connection system, comprising a first screw variant with a shank having a predetermined breaking point, which is arranged between a shank tip and a remaining shank area; a second screw variant, the entire shank of which is as long as the remaining shank area of the first screw variant; at least one component variant with a bore for screwing in both screw variants; wherein the shank of the first screw variant is shorter than the bore and the remaining shank region of the first screw variant has a length which is sufficient for producing a screw connection according to at least one predetermined criterion; the predetermined breaking point is dimensioned in such a way that it can withstand a specified tightening torque and only fails after a specified loosening torque, after which the shank tip remains in the bore. The invention also relates to a method for producing a screw connection by means of such a screw connection system and a motor vehicle with at least one such screw connection.

Description

The present invention relates to a screw connection system and a method for producing a screw connection using such a screw connection system. Furthermore, the invention relates to a motor vehicle with a screw connection that was produced using such a method.

Shear bolts or shear bolts with a shearing bolt head are known per se, and these are also often used in motor vehicles, for example for fastening steering columns in the vehicle. the EP 2 071 201 A1 shows such a shear bolt, for example. The shear bolt is used to clamp a cable in a clamp. In order to be able to clamp cables with different diameters, the shear bolt has two predetermined breaking points with different mechanical properties.

Particularly when a screw connection is oriented vertically, with a screw head arranged at the bottom, a protrusion within a bore, for example in a bushing, can fill with corrosive media in the form of water and, for example, fine solids such as sand and the like, as soon as a such a screw connection is used outside of a drying room in the vehicle. As a result of such corrosion, there may be a risk that the screwed connection cannot be loosened using standard workshop tools and reasonable effort. Rather, there is a risk of the screw head in question shearing off, which can result in a complex removal of the remaining screw within the bore. This can also go hand in hand with expensive repair work on a thread, for example on a socket into which the associated screw was previously screwed.

It is the object of the invention to provide a solution that allows a simple replacement of a screw in a corroded screw connection.

This object is achieved by a screw connection system and by a method for producing a screw connection using a screw connection system having the features of the independent claims. Further possible configurations of the invention are specified in the dependent claims, the description and the figures.

The screw connection system according to the invention comprises a first screw variant with a shank having a predetermined breaking point, the predetermined breaking point being arranged between a shank tip and a remaining shank area of the shank. The rest of the shaft area can be longer than the shaft tip, but it doesn't have to be. Furthermore, the screw connection system includes a second screw variant whose entire shank is as long as the remaining shank area of the first screw variant. In addition, the screw connection system comprises at least one component variant with a bore for screwing in both screw variants. The screw variants can both be screwed individually into the bore of the at least one component variant, as a result of which a screw connection is produced between the screw variant that is screwed in and the component variant. The hole does not have to have been made with a drilling tool. It is also possible that the bore has been produced in a completely different way, for example if the component variant is an injection molded part, the bore can be produced very easily during the production process without any cutting processes. However, the bore can also be a conventional bore that has been produced using a drilling tool.

The shank of the first screw variant is shorter than the bore of the at least one component variant. So if the shank is screwed completely into the bore, there is still a cavity or space within the bore that is not filled by the shank of the first screw variant. In addition, the remaining shank area of the first screw variant is so long, that is to say has such a length, that a screw connection can be produced in accordance with at least one predetermined criterion. The at least one predetermined criterion can include, for example, strength requirements that are placed on the screw connection to be produced. In other words, the remaining shank area of the first screw variant has a length that ensures a secure screw connection according to the at least one predetermined criterion. The predetermined breaking point on the shank of the first screw variant is dimensioned in such a way that it can withstand a specified tightening torque and only fail after a specified loosening torque, after which the shank tip remains in the bore. The loosening torque can be specified such that it corresponds to the torque to be applied when corrosion within the bore and thus between the at least one component variant and the first screw variant has seized the latter quasi inside the bore.

The first screw variant can therefore be screwed into the bore without any problems, during which time said specified tightening torque can be applied without any problems, particularly towards the end of the screwing process, and specifically without the predetermined breaking point failing. If corrosion then occurs within the bore, in particular between an external thread of the first screw variant and the bore, the first screw variant can be removed from the bore again by applying the specified loosening torque, at least to the extent that the predetermined breaking point fails and only the shaft tip in the hole remains.

A new screw connection can then be produced using the screw connection system by simply screwing the second screw variant, the entire shank of which is as long as the remaining shank area of the first screw variant, into the bore. When the second screw variant is arranged as intended within the bore, its shank then abuts the front side of the shank tip of the first screw variant that remains in the bore. Since the entire shank of the second screw variant is as long as the remaining shank area of the first screw variant and the remaining shank area of the first screw variant has a length that is sufficient to produce the screw connection according to the at least one specified criterion, even after partial removal of the first screw variant and screwing in the second screw variant, it can be ensured that a screw connection that satisfies the at least one criterion can be produced again.

Should corrosion occur after the first screw variant has been screwed into the hole, the screw connection can be loosened again with standard workshop tools and without great effort by simply applying at least the specified loosening torque, as a result of which the first screw variant fails at its predetermined breaking point , after which the first screw variant can be easily removed apart from the shaft tip remaining in the bore. If the first screw variant should have a screw head, there is no risk of the screw head shearing off. The remaining screw tip or shank tip of the first screw variant in the hole does not cause any problems, since the second screw variant is dimensioned in terms of its shank length so that it can still be screwed into the hole without any problems, after which a secure screw connection is guaranteed.

The predetermined breaking point on the first screw variant can be, for example, an incision in the radial direction. Viewed from the outside, the predetermined breaking point can therefore have a narrowing of the cross section. This cross-sectional narrowing can be annular, for example. Other types of material weakening are also possible in order to form the predetermined breaking point. Such material weaknesses can be of a geometric nature in particular. However, it is also possible to provide a separate material composition for a predetermined breaking point, so that it has the properties described above.

A possible embodiment of the invention provides that the hole is a through hole. It is envisaged to subject the component variant to cathodic dip painting, so there are advantages if the bore is designed as a through bore. Because in the course of the cathodic dip painting and especially afterwards, by designing the hole as a through hole, it can be ensured that no liquids from the cathodic dip painting remain inside the hole, which could impair a subsequent screwing process and correspondingly a quality of connection.

A further possible embodiment of the invention provides that at least one of the screw variants has a screw head or has no screw head. For example, it is possible that both screw variants each have a screw head. It is also possible that both screw variants are, for example, so-called grub screws or hanger bolts that do not have a screw head. In addition, it is also possible for one of the two screw variants to have a screw head, with the other screw variant not having a screw head.

According to a further possible embodiment of the invention, it is provided that the first screw variant is a self-tapping screw. In this case, the bore does not have an internal thread, since the first screw variant is designed to cut its own thread when it is screwed into the bore. In this case, the second screw variant cannot be a self-tapping screw, since the first screw variant produces a corresponding internal thread as soon as it is screwed into the bore.

An alternative possible embodiment of the invention provides that the borehole is connected to the respective external threads of the screw variants has a suitable internal thread. In this case, both screw variants are not self-tapping or self-tapping screws.

A further possible embodiment of the invention provides that the component variant is a threaded bush. This can be used, for example, in another component or welded to it. However, it is also possible for the component variant to be any other component that has said bore into which the two screw variants can be screwed.

In the method according to the invention for producing a screw connection, the screw connection system according to the invention or a possible embodiment of the screw connection system according to the invention is used, with the first screw variant being screwed into the bore of the component variant until the specified tightening torque is reached. Due to the already described properties of the screw connection system according to the invention or the possible configurations of the screw connection system according to the invention, the first screw variant can be easily removed from the bore again, even if corrosion has occurred that, apart from the remaining shank tip in the bore after failure of the predetermined breaking point, the remaining Part of the first screw variant can be easily removed, after which the second screw variant can simply be screwed into the hole.

In a possible embodiment of the method, it is provided that the tip of the shank is secured in the bore by means of a screw lock. For example, a chemical screw lock, a thread sealant and/or an O-ring can be used to secure the screw, the latter being able to be inserted into an associated groove of the shaft tip, for example. The shank tip, which serves as a kind of plug, can be fixed within the bore in a particularly reliable and sealing manner. Irrespective of when the first screw variant is partially removed again leaving the shank tip behind after failure of the predetermined breaking point, it can thereby be permanently and reliably ensured that the shank tip arranged in the bore seals the bore particularly well.

The motor vehicle according to the invention comprises at least one screw connection that was produced using the method according to the invention or a possible embodiment of the method according to the invention. The screw connection can have both the first screw variant and, after a corresponding repair or replacement measure, the second screw variant.

Further features of the invention can result from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description and the features and feature combinations shown below in the description of the figures and/or in the figures alone can be used not only in the combination specified in each case, but also in other combinations or on their own, without going beyond the scope of the invention to leave.

• 1 eine Seitenschnittansicht einer Schraubverbindung, die durch eine Gewindehülse und durch eine erste Schraubenvariante mit einer Sollbruchstelle gebildet wird;
• 2 eine Seitenschnittansicht der Gewindehülse, nachdem die erste Schraubenvariante teilweise nach dem Versagen der Sollbruchstelle entfernt wurde, wonach lediglich noch eine Schaftspitze der ersten Schraubenvariante in der Bohrung verbleibt;
• 3 eine weitere Seitenschnittansicht der Gewindehülse, wobei diese mit einer zweiten Schraubenvariante eine andere Schraubverbindung bildet.

The drawing shows in:

• 1 a side sectional view of a screw connection, which is formed by a threaded sleeve and by a first screw variant with a predetermined breaking point;
• 2 a side sectional view of the threaded sleeve after the first screw variant has been partially removed after the failure of the predetermined breaking point, after which only a shank tip of the first screw variant remains in the bore;
• 3 another side sectional view of the threaded sleeve, this forming a different screw connection with a second screw variant.

Elements that are the same or have the same function are provided with the same reference symbols in the figures.

A screw connection 10 is shown in a side sectional view in FIG 1 shown. The screw connection 10 is formed by a threaded bushing 12 and a first screw variant 14 . The first screw variant 14 comprises a screw head 16 and a shank 18. The shank 18 has a predetermined breaking point 20 which is arranged between a shank tip 22 and a remaining shank region 24 which is longer than the shank tip 22.

The shank 18 is shorter than a bore 26 of the threaded bushing 12. The remaining shank region 24 has a length L that is sufficient for producing the screw connection 10 according to at least one predetermined criterion. In other words, adapted to the application area of the screw connection 10, the length L of the remaining shank 24 alone is sufficient such that, for example, forces occurring during operation can be reliably absorbed or withstood and a secure screw connection can thus be ensured.

The predetermined breaking point 20 is dimensioned in such a way that it easily withstands a predetermined tightening torque when screwing in the first screw variant 14 and only fails from a predetermined loosening torque, after which only the shaft tip 22 has to remain in the bore 26 when the remaining part of the first screw variant 14 wants to remove from the bore 26. For example, it can happen that, due to corrosion, the first screw variant 14 has seized with its shank tip 22 within the bore 26, with the intention of removing the first screw variant 14. Then said specified loosening torque has to be applied or even exceeded, as a result of which the predetermined breaking point 20 fails and apart from the shank tip 22 the remaining first screw variant 14 can be removed from the bore 26 .

In the case shown here, the predetermined breaking point 20 is designed as a kind of ring-shaped radial incision, from the outside. However, other types of material weakening, in particular of a geometric nature, are also possible in order to form the predetermined breaking point 20 . In addition, it is also possible to provide a separate material composition at the predetermined breaking point 20 so that it has the said properties, ie it can withstand the predetermined tightening torque and fail from the predetermined loosening torque.

In 2 the threaded bushing 12 is again shown in a side sectional view, with the remaining part of the first screw variant 14 being removed apart from the shank tip 22 . The bore 26 designed as a through bore is sealed by the remaining shaft tip 22 . The shank tip 22 thus forms a kind of plug within the bore 26. The sealing effect of the shank tip 22 can be further improved, for example, by introducing a thread sealant between the shank tip 22 and the bore 26. In addition, a groove (not shown here) can also be provided on the outside of the shaft tip 22, into which an O-ring (not shown here) is inserted.

In 3 Another variant of the screw connection 10 is shown, which differs in that a second screw variant 28 has been screwed into the bore 26 . The part of the first screw variant 14 in the form of the shank tip 22 that remains in the bore 26 still belongs to this further variant of the screw connection 10. A shank 30 of the second screw variant 28 is overall as long as the remaining shank region 24 of the first screw variant 14, has a length L. The shaft tip 22 has a length l. If you add the lengths L and I, the result is the total length of the shank 18 of the first screw variant 14. The threaded bushing 12 in turn has a total length L+x, where x is greater than I, so the bore 26 of the threaded bushing 12 longer than the shank 18 of the first screw variant 14 and also longer than the shank 30 of the second screw variant 28 together with the shank tip 22 remaining in the bore 26.

After removing the first screw variant 14, with the shank tip 22 remaining within the bore 26, if the specified loosening torque had to be applied to loosen the screw connection 10, this does not affect the re-establishment of the screw connection 10, since the second screw variant 28 can easily be inserted into the bore 26 can be screwed. The length L of the shank 30 of the second screw variant 28 is dimensioned such that it fits at least essentially precisely into the bore 26 so that when the second screw variant 28 is arranged as intended, the shank 30 rests against the shank tip 22 remaining in the bore 26 the first screw variant 14 arrives.

Reference List

10

screw connection

12

threaded bush

14

first screw variant

16

screw head

18

Shaft of the first screw variant

20

Predetermined breaking point of the shank of the first screw variant

22

shank tip

24

remaining shaft area

26

drilling

28

second screw variant

30

Shank of the second screw variant

I

Length of shaft tip

L

Length of the remaining shank area of the first screw variant or of the entire shank of the second screw variant

L+x

length of the hole

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 2071201 A1 [0002]

Claims (10)

Screw connection system, comprising - A first screw variant (14) with a shank (18) having a predetermined breaking point (20) and which is arranged between a shank tip (22) and a remaining shank region (24); - A second screw variant (28) whose entire shank (30) is as long as the remaining shank region (24) of the first screw variant (14); - At least one component variant (12) with a bore (26) for respectively screwing in both screw variants (14, 28); whereby - the shank (18) of the first screw variant (14) is shorter than the bore (26) and the remaining shank region (24) of the first screw variant (14) has a length (L) which is sufficient for producing a screw connection (10) according to at least is sufficient for a given criterion; - The predetermined breaking point (20) is dimensioned such that it can withstand a predetermined tightening torque and only fails after a predetermined loosening torque, after which the shank tip (22) remains in the bore (26). screw connection system claim 1 , characterized in that the bore (26) is a through bore. Screw connection system according to one of the preceding claims, characterized in that at least one of the screw variants (14, 28) has a screw head (16) or has no screw head (16). Screw connection system according to one of the preceding claims, characterized in that the first screw variant (14) is a self-tapping screw. Screw connection system according to one of Claims 1 until 4 , characterized in that the bore (26) has an internal thread matching the respective external threads of the screw variants (14, 28). screw connection system claim 5 , characterized in that the component variant is a threaded bush (12). Method for producing a screw connection (10) using a screw connection system according to one of the preceding claims, in which the first screw variant (14) is screwed into the bore (26) of the component variant (12) until the specified tightening torque is reached. procedure after claim 7 , characterized in that the shaft tip (22) is secured in the bore (26) by means of a screw lock. procedure after claim 8 , characterized in that a chemical screw lock, a thread sealant and/or an O-ring is used to secure the screws. Motor vehicle with at least one screw connection (10) by means of a method according to one of Claims 7 until 9 was produced.

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