DE102018210893A1 - Screw element and method for producing such a screw element - Google Patents

Abstract

The invention relates to a screw element (2) with a head part (3) and with a shaft part (4) which is connected to the head part (3) and has a threaded region (5) with an external thread (6) and which extends along its longitudinal direction (1). is hollow at least in one length region (8) and thereby has at least in the length region (8) a hollow cross-section (9, 14) running along the longitudinal direction (1) of the shaft part (4). According to the invention, the head part (3) and the shaft part (4) are formed from a tubular element (10) which is formed without cutting at least in a partial area (11) and thereby in the partial area (11) the head part produced by the forming (3), which closes the hollow cross section (9, 14) along the longitudinal direction on the side of the head part. The invention further relates to a method for producing such a screw element.

Description

The invention relates to a screw element of the type specified in patent claim 1 and a method for producing such a screw element according to patent claim 9.

A large number of screwing elements are used in vehicle construction, in particular series vehicle construction, in order to screw or brace components of a motor vehicle to one another. Although a tightening torque of the screwing element is monitored or controlled during manufacture of the motor vehicle, the screwing arrangement and / or the components of the motor vehicle screwed together by means of the screwing element can loosen the screwing arrangement or screw connection over time due to a setting behavior. This leads to the fact that, in particular in the event of a traffic accident of the motor vehicle, the components of the motor vehicle which are screwed to one another are displaced relative to one another by forces occurring in the event of a traffic accident and, as a result, the screw element is undesirably subjected to shear stress. This can result in a component or several components of the motor vehicle being / being torn off in a traffic accident because of a sheared screw element.

To counteract this problem, it is conceivable to use the screw element to generate a particularly strong frictional connection between the components of the motor vehicle to be screwed, and to ensure that this frictional connection is still sufficiently strong even after the components and / or the screw element have been set in order to - Even in the event of a traffic accident of the motor vehicle - to prevent a relative movement to one another and consequently a shearing off of the screw element. This can be achieved, for example, by a particularly high pretensioning force due to a particularly high tightening torque of the screw element. Given a given dimension of the respective screw element, however, a particularly high tightening torque would place excessive stress on the screw element, as a result of which it could tear off.

Accordingly, more stable, in particular larger or thicker screw elements could be used. A higher tightening torque can be applied to thicker or more stable screw elements, which results in a higher pretensioning force when the screw element is tightened, but the thicker screw element, due to its particularly low elasticity, cannot adequately compensate for the setting behavior of the components. This means that the pretensioning force drops particularly strongly with the thicker screw elements, since the components settle more than the thicker screw element can contract from its expansion. Such more stable or thicker screw elements would also lead to a particularly high vehicle mass, which is why thicker screw elements are diametrically opposed to the idea of lightweight vehicle construction and / or a particularly fuel-efficient, energy-efficient and / or low-emission motor vehicle.

There is therefore basically a need for particularly stable, in particular tensile, screw elements which are particularly mass-efficient. For example, the DE 103 19 236 A1 a hollow screw, through the shaft of which an inner profile runs, which is suitable as an actuating profile for the use of screwing tools. In a manufacturing process of this hollow screw, its shaft is produced from a drawn or extruded, thick-walled tube, a head of the hollow screw being carried out by gradually widening and turning over the mushroom shape that is formed.

This conventional hollow screw has a continuous channel element, so that objects and / or fluids can pass through this channel element through this conventional hollow screw and consequently through the screw connection formed by means of this conventional hollow screw. Therefore, the conventional banjo bolt is not suitable for use on the outer skin of the motor vehicle, since there would otherwise be the danger that objects, for example dust, moisture, etc., could enter an interior of the motor vehicle and the motor vehicle there damage, for example, corrode or promote corrosion. Although the duct element can be closed by means of adapted plugs, these plugs can be loosened and fall out, for example due to vibrations, so that a reliable sealing effect is no longer provided. Furthermore, the banjo bolt is then only particularly expensive to install, since the plugs would have to be inserted in one work step.

It is an object of the invention to provide a particularly stable and mass-efficient screw element which can be used in a particularly flexible manner and is particularly easy to produce.

This object is achieved according to the invention by a screw element with the features of claim 1 and by a method with the features of claim 9 for producing such a screw element. Advantages and advantageous embodiments of the Screw element according to the invention are to be regarded as advantages and advantageous refinements of the method according to the invention for producing such a screw element and vice versa. Advantageous embodiments of the invention are the subject of the dependent claims and the description.

According to the invention, a screw element is provided which comprises a head part and a shaft part connected to the head part and having a threaded area with an external thread. The shaft part is hollow at least in one longitudinal region along its longitudinal direction of extension and thereby has at least in the longitudinal region a hollow cross section running along the longitudinal direction of the shaft part.

In order to further develop such a screw element in such a way that it is particularly stable and mass-efficient and can be used in a particularly flexible manner and can be produced with little effort, it is also essential to the invention that the head part and the shaft part are formed from a tubular element which is formed without cutting at least in a partial area and thereby forms in the partial area the head part produced by the forming, which closes the hollow cross section along the longitudinal direction on the side of the head part. Because the screw element is hollow at least in the length range, that is, in contrast to a solid screw in the length range, it has less material, the screw element is particularly mass-efficient. Studies have shown that, unlike the solid screw, which is not hollow, the screw element can transmit a similar amount of torque and a similar amount of tensile force. As a result, a lightweight design concept is taken into account in a particular manner while the performance of the screw element remains approximately the same, since, given a given screw element dimension, it can be designed or designed to be particularly light and stable.

Furthermore, the screw element can be used particularly flexibly, since the hollow cross section is closed on the head part of the screw element. As a result, objects and / or fluids are effectively prevented from penetrating into the hollow cross section via the head part and penetrating the screw element. This means that the screw element can also be used on an outer skin of the motor vehicle, without having to fear that objects, for example dust, etc., and / or fluids, for example water, oil, etc., can enter the screw element from the outside Inside the motor vehicle and damage the motor vehicle there, for example favor corrosion.

In addition, the screw element can be produced with little effort, since the head part and the shaft part are formed from the tubular element. Pipe elements are particularly simple and freely available on the market in a variety of material grades. Furthermore, such a tubular element already has the hollow cross section of the shank part of the screw element, so that there is no need to drill or drill the hollow cross section, for example from a round rod. This also leads to a particularly material-efficient production of the screw element.

In particular, such a screw element according to the invention is provided to provide a particularly long extension length even with short screw elements or screws. The screw element can be a screw of size M5 to M12 , preferably by size M6 to M11 , particularly preferred by size M7 to M10 , especially the size M8 be trained. In connection with this, a screw element described here can be regarded as "short" if its shaft length corresponds to approximately two to five times the nominal thread diameter. Likewise, the principles described herein are still applicable to longer screw elements.

In a further development of the screw element, it is provided that the tubular element forming the shaft part and the head part is formed in one piece, as a result of which the shaft part is formed in one piece with the head part. On the one hand, this means that the pipe element used for the production of the screw element is not composed of several partial pipe elements which are produced separately and then connected. On the other hand, this means that, due to the one-piece tubular element, the shaft part and the head part are integrally formed with one another. In other words, a material of the one-piece tubular element is the same as a material of the shaft part and the head part. The screw element is therefore even easier to produce, since it is not necessary to connect, for example weld, the shaft part and the head part to one another and / or the partial tube elements to one another.

It is particularly preferred if the hollow cross section of the screw element is free of an angular shape on the inside circumference. This means that the hollow cross section, at least in the length range, is free from one corner or free from several corners. It can be provided that the hollow cross section has an at least substantially circular shape. In particular, it is to be understood that the hollow cross section along the entire length range is free of an angular shape on the inner circumference side. Due to the circular hollow cross section, the screw element is special Can be produced with little effort, since an angular contour, for example a torque-transmitting and / or form-lockable tool attack on the shaft part, is dispensed with. This means that particularly high tolerances can be permitted in the manufacture of the screw element in the hollow cross section, in particular on the inner circumference side, without restricting a functionality of the screw element.

In order to produce a particularly reliable frictional connection between two components clamped together by means of the screw element, it can be provided in a further development of the screw element that the shaft part has an expansion area that is at least thread-free on the outer circumferential side between the head part and the threaded area in the longitudinal direction of extension of the shaft part. As a result, when the screwing element and / or the components are set, it is effectively prevented that the clamping force of the screwing element, which is the cause of the frictional engagement acting between the components, diminishes to such an extent that the frictional engagement yields in a given load case and a relative movement of the components to one another , especially across the screw element. This is because the screwing element can be stretched over its expansion area along the longitudinal direction of the shaft part, so that a particularly high tightening torque can be applied to the screwing element, whereby a particularly high pretensioning force of the screwing element generates the frictional connection between the components to be screwed or screwed. In particular, such a high tightening torque is applied to the screw element that even after a loss of preload due to the screw element or the components being set, the frictional engagement generated between the components fully satisfies the required load case.

The expansion area can in particular have a smaller outer circumference than the thread area. In other words, the expansion area can have a smaller radius or diameter than the thread area. This means that the screw element can be designed as an expansion screw, in which the thread area projects beyond the expansion area in the radial direction. Since the expansion area is thread-free and has a smaller outer circumference than the thread area, the expansion area can be arranged or arranged without contact to a receiving hole of the screw element. It can thus be ensured that the stretching area is intended to be freely stretchable in the receiving hole by applying the tightening torque to the screw element, without being positively and / or positively supported on an inner circumferential surface of the receiving hole, which could hinder and / or prevent the intended stretching of the stretching area. It can be provided that the hollow cross section is smaller in the expansion area than in the thread area.

The screw element with the expansion area or the expansion screw is particularly easy to manufacture if the shaft part has a transition area arranged in the longitudinal direction of the shaft part between the expansion area and the head part, which tapers in the longitudinal direction of the shaft part, in particular towards the expansion area. This means that the shaft part has a larger diameter where it directly adjoins the head part via the transition region than where the transition region directly adjoins the expansion region. For example, the transition region, at least on the outside, may have a frustoconical shape or at least one radius all around. Such a transition area can alternatively or additionally be provided between the expansion area and the thread area of the screw element. Due to the transition area or the transition areas, the screw element can be used particularly flexibly, since there is no vertical projection between the head part and the stretching area and / or between the stretching area and the thread area, which projection could only be produced by means of an undesired machining process anyway.

It has proven to be further advantageous if the head part has a larger outer circumference than the shaft part. In other words, the head part has a larger diameter than the shaft part, which means that a largest diameter of the shaft part is smaller than a smallest diameter of the head part. The tightening torque can be applied to the screwing element in a particularly effortless manner via the head part, which has a larger diameter than the shaft part. In contrast to head-free threaded rods or grub screw elements, the respective head part diameter of which corresponds at least substantially to the shaft part diameter or is smaller than the shaft part diameter, a particularly preferred contact surface is created in the case of a head part which is larger in relation to the shaft part. The screw element can be supported on one of the components to be screwed via this contact surface, so that the components can be clamped together particularly efficiently.

Furthermore, the head part can have a tool engagement, via which the head part can be coupled, in particular in a form-fitting manner, to a tool for driving the screw element. This means that the head part can have the tool attack along its outer circumferential surface, which, for example, as an external hexagon External multi-tooth, etc., can be formed. Alternatively or additionally, the head part can have a further tool attack, which can be designed, for example, as an internal hexagon, as an internal multi-tooth, as an internal hexagon (known as “Torx”), etc. As a result, the screw element can be used in a particularly flexible manner, since well-known tools can be used for screwing the screw element into the receiving hole.

The invention further relates to a method for producing a screw element, which can in particular be the screw element described above. In this method, a head part and a shaft part connected to the head part and having a threaded region with an external thread are produced. The shaft part is hollow at least in one longitudinal region along its longitudinal direction of extension and thereby has at least in the longitudinal region a hollow cross section running along the longitudinal direction of the shaft part.

In order to provide a particularly stable and mass-efficient screw element, which can be used in a particularly flexible manner and is particularly easy to produce, the invention provides that the head part and the sheep part are made from a tubular element. The tubular element is formed without cutting at least in a partial area, as a result of which in the partial area the head part which closes the hollow cross section along the longitudinal extension direction on the side of the head part is produced as a result of the forming. This means that firstly the head part is created by reshaping the partial area, which secondly is calibrated exactly to a desired dimension, for example a key dimension.

By means of this method, the screw element can be produced in a particularly mass-efficient manner and with little effort. By eliminating machining of the tubular element, it is ensured that a fiber course of the tubular element and consequently a fiber course of the screw element is not interrupted or remains uninterrupted, so that a particularly high tensile force can be transmitted along the shaft part via the screw element. This means that the screw element produced by the method can be used with a particularly high tightening torque, from which a particularly high clamping force or preload force and, consequently, a particularly high and reliably formed frictional connection between components to be screwed or screwed by means of the screw element can be generated.

In particular, it is provided that the tubular element has a time before the hollow cross section is formed. This means that machining the pipe element in order to give it the desired hollow cross section can be omitted. It is particularly preferred if a dimension of the hollow cross section, for example an inner diameter, in the unprocessed state corresponds to a coupling device of a tool involved in the production or manufacture of the screw element. This means that the method for producing the screw element can be carried out particularly easily and / or with little effort. In addition, the screw element is produced in a particularly material-efficient manner, since there is no machining of the tubular element and / or the screw element.

Furthermore, it can be provided in the method for producing the screw element that the hollow cross section passes through the tubular element along its entire longitudinal direction before the forming. In other words, the hollow cross section along the longitudinal extension direction of the tubular element is unsealed or unlimited at both ends of the tubular element before the forming, so that the hollow cross section opens out at or in the vicinity of the tubular element along both directions of the tubular element. Such a tubular element is available and available on the market in a particularly unproblematic manner. This means that a commercially available tubular element can be used to produce the screw element, which means that the method for producing the screw element can be carried out with less effort. It is particularly conceivable - especially with sufficiently small diameters of the tubular element - that the tubular element is used as rolled and / or drum goods in the method for producing the screw element.

The method for producing the screw element can have the following steps: In a first method step, a die having a mandrel is provided. In a further method step, the tubular element is placed on the mandrel by at least partially inserting the mandrel into the hollow cross section of the tubular element. In yet another process step, the tubular element is shaped while the tubular element is placed on the mandrel, so that the tubular element is held by means of the mandrel during the shaping. In particular, it can be provided that the die forms the head part of the screw element during the shaping. In a further development of this method it can be provided that when the tubular element is reshaped, it is formed in one piece via the die of the head parts together with a tool attack. In particular, this tool attack can be the tool attack described in connection with the screw element or several act such tool attacks. It is particularly preferred if the mandrel has a circular-conical or frustoconical outer contour in order to be able to detach the mandrel and the tubular element from one another in a particularly simple manner, in particular after the tubular element has been deformed. Furthermore, the mandrel can have a stepped design, so that a larger hollow cross section is formed in the thread area than in the expansion area.

This method can furthermore be carried out at least once again, in particular using a further die, an intermediate product emerging from the previous implementation of the method. Here, the further die can have a mandrel, the outer peripheral surface of which is smaller than the mandrel of the first die. This smaller mandrel of the further die for the intermediate product corresponds to an opening of the intermediate product, as a result of which the intermediate product is held particularly reliably by means of the smaller mandrel or by means of the further die. In this way, the desired screw element can be produced from the tubular element in several sub-processes, one of the hollow cross-sections becoming ever smaller and finally being closed.

It is particularly preferred if cold upsetting is carried out as the forming. In this way, it is ensured in a particularly reliable manner that — as described further above — a fiber course of the screw element, in particular of the shaft part, remains uninterrupted when the screw element is manufactured. As a result, the screw element produced by the method is particularly powerful, that is to say the screw element produced by the method can exert a particularly high force on two or more components to be connected or connected by means of the screw element, so that a particularly reliable frictional connection can be generated between these components ,

Further features of the invention result from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or on their own.

• 1 in schematischer und entlang einer Längserstreckungsrichtung radial geschnittener Darstellung ein Schraubelement;
• 2 in schematischer und entlang einer Längserstreckungsrichtung radial geschnittener Darstellung ein Rohrelement;
• 3 in schematischer und quer zu einer Längserstreckungsrichtung radial geschnittener Darstellung das Rohrelement;
• 4 in schematischer Darstellung einen Kopfteil des Schraubelements in einer Draufsicht;
• 5 in schematischer Darstellung das Rohrelement und unterschiedliche, aus einzelnen Verfahrensschritten eines Verfahrens zum Herstellen des Schraubelements hervorgehende Zwischenprodukte sowie das Schraubelement; und
• 6 in schematischer Darstellung das Rohrelement aus 2, wie dieses in ein Gesenk eingesetzt ist.

The invention will now be explained in more detail using a preferred exemplary embodiment and with reference to the drawings. It shows:

• 1 in a schematic and along a longitudinal direction radially sectioned a screw element;
• 2 in a schematic and along a longitudinal direction radially sectioned representation of a tubular element;
• 3 in a schematic and transverse to a longitudinal direction radially sectioned representation of the tubular element;
• 4 a schematic representation of a head part of the screw element in a plan view;
• 5 a schematic representation of the tubular element and different intermediate products resulting from individual method steps of a method for producing the screw element and the screw element; and
• 6 in a schematic representation of the tubular element 2 how this is inserted into a die.

Identical or functionally identical elements are provided with the same reference symbols in the figures.

1a shows in a schematic and along a longitudinal direction 1 radially sectioned a screw element 2 which has a headboard 3 and a shaft part 4 having. The headboard 3 and the shaft part 4 are integrally formed with each other so that the shaft part and the head part are connected to one another. The shaft part 4 has a threaded area 5 on, which comprises an external thread 6. It is particularly preferred if the external thread 6 is non-cutting on the shaft part 4 is formed, for example by means of rolling. At least the shaft part 4 can be rotationally symmetrical with respect to a longitudinal center axis 7 of the screw element 2 be trained while the headboard 3 can deviate from a rotationally symmetrical shape, in particular if it is equipped with a tool attack.

In 1a it can also be seen that the shaft part 4 a length range 8th has, which along the longitudinal direction 1 , which is in particular a longitudinal direction of the shaft part 4 can act, is hollow. As a result, the screw member 2 , at least in the length range 8th , a hollow cross section 9 on, causing the screw element 2 significantly different from a solid screw known from the prior art. Due to the hollow cross section, the screw element 2 , especially in comparison with the solid screw, particularly mass-efficient. In order to make the screw element particularly stable and flexible, provided that the headboard 3 and the shaft part 4 from a tubular element 10 are formed. This is at least in one area 11 reshaped without cutting, thereby reshaping the head part 3 is formed. The headboard 3 closes along the longitudinal direction 1 and / or along the longitudinal center axis 7 of the screw element 2 the hollow cross section 9 on the side of the head part 3

That means the hollow cross section 9 is closed on the head side by means of the reshaping at least to such an extent that over the head part 3 or over the sub-area 11 penetration of an object and / or a fluid into the hollow cross section 9 which towards the headboard 3 can taper towards, at least obstructed, ideally completely avoided. That means the hollow cross section 9 On the head side, for example, fluid-tight by reshaping the partial area 11 or the manufacture of the headboard 3 is closed. At one foot end 12 , which is along the longitudinal center axis 7 the headboard 3 opposite, the hollow cross section opens 9 via a foot opening 13 in or to an environment of the screw element 2 , If you want to prevent fluids and / or objects through the foot opening 13 into the interior of the hollow cross section 9 reach, for example, corrosion inside the screw element 2 To avoid, a closure element, not shown, can be provided, which with the foot-side opening 13 corresponds and by means of which the foot opening 13 closable, in particular fluidically closable.

2 shows in a schematic and along the longitudinal direction 1 radially sectioned representation of the tubular element 10 , Since that in 1 shown screw element from the in 2 shown pipe element 10 is producible or manufactured, it is to be understood that a longitudinal center axis of the tubular element 10 with the longitudinal center axis 7 of the screw element 2 coincides. The pipe element 10 , from which after the forming the screw element 2 emerges, is formed in one piece. That means that the pipe element 10 along the longitudinal direction 1 or the longitudinal center axis 7 uninterrupted, especially seamless, extends. As a result - especially when you look together 1 with the 2 - clear that the headboard 3 together with the shaft part 4 is integrally formed by the tubular element 10 is formed without cutting.

The pipe element 10 has a hollow cross-section before forming 14 , from which during the forming or by means of the forming the hollow cross section 9 of the screw element 2 evident. But it is equally conceivable that the hollow cross section 14 of the undeformed tubular element 10 before forming, at least essentially the hollow cross section 9 of the screw element 2 equivalent. In other words, the hollow cross section 14 of the tubular element 10 like the hollow cross-section before forming and dimensioning 9 of the screw element 2 be trained.

3 shows in a schematic and transverse to the longitudinal direction 1 radially sectioned representation of the tubular element 10 , It can be clearly seen that the hollow cross section 9 on its inner peripheral surface 15 is free of an angular shape or free of a corner or edge. Accordingly, the hollow cross section 9 at least along the inner peripheral surface 15 be oval and / or elliptical. In the present example is the hollow cross section 9 inner circumferential side, that is, along the inner circumferential surface 15 circular design. As a result, the tubular element 10 have an annular cross section. Because of this corner-free inner peripheral surface 15 are no special requirements for the pipe element 10 put out the screw element 2 to shape.

The screw element 2 can - as in 1b shown - be designed as an expansion screw, which means that the screw element 2 optionally an expansion range 16 may have, which in 1b is shown. For example, the shaft part 4 the stretching range 16 have which between the head part 3 and the thread area 5 is arranged. It is particularly provided that the expansion range 16 is thread-free. In other words, the stretching area extends along the longitudinal direction 1 or along the longitudinal center axis 7 between the headboard 3 and the thread area 5 so that the stretching range 16 to the headboard 3 and the thread area 5 borders.

The stretch area 16 can be designed thread-free on the outer circumference side or on the inner circumference side. Furthermore, the expansion range 16 to be thread-free on the outer circumference side and on the inner circumference side. In addition - as in the present example - the expansion range 16 a smaller outer circumference than the thread area 5 exhibit. That means the stretch range 16 opposite the thread area 5 can have a smaller radius than the thread area 5 , in particular as a thread core radius of the external thread 6 ,

The stretch area 16 can have a transition area at the top 17 to the headboard 3 of the screw element 2 adjoin so that the headboard 3 directly to the transition area 17 adjacent and this directly to the stretching area 16 borders. Here, the transition area tapers 17 starting from the headboard 3 in the direction of the expansion area, that is to say in the direction of longitudinal extension 1 , so that an outer diameter of the head The transition area 17 is greater than an outer diameter of the transition region on the expansion region side 17 , The transition area 17 viewed in cross-section in this context can have at least one concave radius. When reshaping the tubular element 10 becomes the transition area 17 as part of the shaft part 4 generated so that the headboard 3 and the transition area 17 are integrally formed with each other. Similarly, the transition area 17 and the stretch range 16 formed integrally with one another.

The screw element 2 can have another transition area 18 which the transition area 17 along the longitudinal center axis 7 is opposite and between the stretching range 16 and the thread area 5 is arranged. The further transition area 18 tapers - analogous to the above description of the transition area 17 - against the longitudinal direction 1 of the shaft part 4 starting from the thread area 5 towards the stretch area 16 , That means the thread area 5 the stretching range 16 towered over in the radial direction.

1 also shows the headboard 3 , which has a larger outer circumference than the shaft part 4 having. In other words, the head part protrudes 3 the shaft part 4 in the radial direction. In a schematic representation is in 4 a top view of the headboard 3 of the screw element 2 shown. The head part shows only by way of example 3 in 4 a hexagonal shape. Alternatively or additionally, the head part 3 as a circular cylindrical head, as a countersunk head, as a round and / or semicircular head, as a lens head, etc. Furthermore, the head part 3 a tool attack 19 over which the head part 3 with a tool for driving the screw element 2 can be coupled. The hexagonal head shape of the head part shown as an example 3 enables, for example, the coupling of an open-ended spanner, via which the screw element 2 , especially its shaft part 4 to the longitudinal center axis 7 is driven to rotate. That means the hexagonal head shape of the headboard 3 the tool attack 19 forms. Alternatively or additionally, the head part 3 another tool attack 20 have, as is already well known from the prior art. In the present example is the further tool attack 20 formed as a hexagon socket, so that the screw element 2 by means of a further tool attack 20 corresponding external hexagon around the longitudinal center axis 7 is rotatable and as a result can be driven.

The following is a method for manufacturing the screw element 2 described. This shows 5 the pipe element in a schematic representation 10 and different intermediate products resulting from individual process steps of the method for producing the screw element 21 . 22 . 23 . 24 as well as the screw element 2 ,

An essential difference from a conventional method for producing a conventional screw element is that the tubular element 10 as the starting product for the screw element 2 is used. In other words, instead of thinning out from the outside (as in the case of producing a conventional screw element from a conventional full round rod), thinning takes place on the inner circumferential surface 15 of the tubular element 10 , Otherwise it can be provided that the tubular element 10 analogous to the full round rod, which in contrast to the tubular element 10 does not have an annular but a circular cross section, is processed to the screw element 2 manufacture. In contrast to the full round rod, a torque can be achieved by means of the tubular element 10 be transferred more easily.

Accordingly, the screw element 2 be created by means of the method of manufacturing the same by the head part 3 and the shaft part 4 from the pipe element 10 are produced, the pipe element 10 in the section 11 is formed without cutting. As a result of the non-cutting forming of the tubular element 10 or the section 11 becomes the hollow cross section there 9 along the longitudinal direction 1 or along the longitudinal center axis 7 locked. That means the hollow cross section 9 on the head side, that is in an area of the head part 3 , especially through the headboard 3 , is closed. In other words, the hollow cross section 9 on the side of the headboard 3 closed, in particular fluidically closed by in the partial area 11 the pipe element 10 is reshaped such that the head part there 3 will be produced.

As already stated, the tubular element forms 10 the starting material for producing the screw element 2 , so that during the non-cutting shaping of the tubular element 10 or by reshaping the tubular element 10 from it the screw element 2 evident. This means that in the process for producing the screw element 2 it is provided that the tubular element 10 before the forming of the hollow cross section 14 of the tubular element 10 already has, from which - as already described above - the hollow cross section 9 evident. For example, an outer diameter of the tubular element 10 be selected slightly smaller than an outer diameter of the screw element 2 or the hollow cross section 9 , An inner diameter of the tubular element can also be used 10 can be selected slightly larger than an inner diameter of the screw element 2 or the hollow cross section 9 , This offers the advantage that a Tolerance quality of the screw element 2 during or by means of the manufacture of the same, and not by the tubular element 10 is determined.

Accordingly, a manufacturing step that includes forming a material recess in a full round rod is obsolete, since this material recess is naturally already in the tubular element 10 is available. As a result, the method for producing the screw element comprises 2 particularly few process steps, so that the screw element by means of the process 2 can be produced particularly efficiently.

In this context, it is particularly preferred if the hollow cross section 14 before the forming of the pipe element 10 along its entire longitudinal direction, in particular along the longitudinal center axis 7 , interspersed, for example completely penetrated. In other words, and referencing the 2 it means that the pipe element 10 two opposite and oppositely oriented ends 25 has, which each have an annular shape, so that the annular shape of the respective ends 25 with respect to the longitudinal center axis 7 coaxial and congruent with the hollow cross section 14 of the tubular element 10 are. Accordingly, at the end 25 a respective pipe opening 26 formed which over a channel element 27 are fluidly connected to each other. From one of the pipe openings 26 goes the foot opening 13 out. That means the pipe element 10 over its channel element 27 can be flowed through by a fluid or that via the channel element 27 a sufficiently small object the tubular element 10 along the longitudinal direction 1 can penetrate. In other words, the channel element opens out 27 at both ends 25 of the tubular element 10 in an environment of the tubular element 10 ,

It is particularly preferred to manufacture the screw element 2 a die 28 provided which is a thorn 29 and / or a negative form 30 an outer contour of the screw element 2 can have. Accordingly shows 6 in a schematic representation of how the tubular element 10 for the production of the screw element 2 into the die 28 is used. The negative form 30 can with a desired shaft shape of the shaft part 4 of the screw element 2 correspond so that when reshaping the tubular element 10 the shaft part 4 according to the negative form 30 is trained. In particular, it is provided that the mandrel 29 towards the tubular element 10 is tapered, for example conical or circular cone-shaped and / or circular truncated cone-shaped, so that after the pipe element has been deformed 10 this again particularly easy from the thorn 29 is solvable. Because of the conical or frustoconical shape of the mandrel 29 there is only a particularly low risk of being formed between the mandrel 29 and the inner peripheral surface 15 of the tubular element 10 such a strong frictional connection is generated that the tubular element 10 or the screw element 2 only with excessive force from the die 28 or from the thorn 29 can be solved. Correspondingly goes from the hollow cross section 14 of the tubular element 10 when manufacturing the screw element 2 a conical hollow cross section 9 emerges, with a pulling of the tubular element 10 or the screw element 2 from the die 28 due to the conical mandrel 29 and / or the conical hollow cross section 9 can be done particularly easily. In 6 is the conical hollow cross section 9 by the diameter d1 and d2 shown, the diameter d1 in the section 11 of the tubular element 10 or the screw element 2 is smaller than the diameter d2 at the later foot end 12 of the screw element 2 (d1 ≤ d2). That means the thorn 29 can have respective diameters at the corresponding points, which correspond to the diameters d1 . d2 at least essentially correspond. In addition, the thorn 29 be designed stepped so that in the threaded area 5 a larger hollow cross section 9 can be calibrated as in the expansion range 16 ,

It is further provided that the mandrel 29 down to the sub-area 11 stretched in so that the headboard 3 of the finished screw element 2 still partially the hollow cross section 9 having. In other words, the thorn 29 longer than the finished shaft part 4 of the finished screw element 2 ,

In a further, for example second process step, the pipe element 10 on the thorn 29 put on by the thorn 29 at least partially in the hollow cross section 14 of the tubular element 10 is plugged in. Likewise, the tubular element 10 by placing this on the thorn 29 is plugged into the die 28 or in its negative form 30 used, for example plugged in. That means that in this state the negative form 30 or the die 28 the pipe element 10 encompasses at least in some areas.

In a further, for example third, process step, the tubular element is deformed 10 while the pipe element 10 on the thorn 29 is placed or in the negative form 30 is inserted so that the tubular element 10 during the forming by means of the mandrel 29 and / or by means of the negative form 30 is held. For this purpose, provision is made in particular for cold upsetting to be carried out as the reshaping, in particular along the longitudinal direction 1 or along the longitudinal center axis 7 , a compressive force 31 on the tubular element 10 is applied so that the tubular element 10 in the negative form 30 is compressed. Cold upsetting or cold forming has the advantage that material and / or structural fibers of the tubular element 10 and consequently the screw element 2 not be interrupted during the forming process. Because of this, the screw element is by means of the method 2 producible, which is particularly powerful, in particular with regard to an at least substantially parallel to the longitudinal center axis 7 acting tensile force or tension or pretensioning force is formed.

The die 28 can be part of a forming tool 32 be the die 28 can be designed as a lower die. The forming tool can accordingly 32 another die, in particular designed as an upper die 33 have the lower die 28 is opposite. Accordingly, the compressive force 31 on the tubular element 10 be applied by the two dies 28 . 33 to be moved towards each other. The other die 33 or the upper die 33 can be another negative form 34 have with a desired shape of the head part 3 corresponds. The negative form 34 is trained to the sub-area 11 to record when upsetting the tubular element 10 the headboard 3 train. In particular, the negative form 34 Have structures by means of which the tube element is compressed 10 the tool attack 19 and / or the tool attack 20 integral with the headboard 3 is trained.
Because the outer diameter of the tubular element 10 can be selected slightly smaller than an outer diameter of the screw element 2 or the hollow cross section 9 and / or the inner diameter of the tubular element 10 can be selected slightly larger than an inner diameter of the screw element 2 or the hollow cross section 9 , the tolerance quality of the screw element 2 in making it by the die 28 and not through the pipe element 10 certainly. To carry out a length compensation, for example due to fluctuations in a pipe element length, so that the screw element produced 2 a length corresponding to the required tolerance quality can be provided, a depth of the tool attack 20 to vary. Because when manufacturing the screw element 2 would be a pipe element too short 10 for example, cause the same depth of tool attack 20 the headboard 3 would be formed with too little material. By deepening the tool attack 20 becomes material the headboard 3 fed, so that this also with a too short pipe element 10 is trained as desired. Alternatively or additionally, provision can be made for an indentation on the head part, which is not defined in more detail, for length compensation 3 is inserted, for example, in order to - analogous to deepening the tool attack 20 - the headboard 3 if the tube element is too short 10 train correctly. This means that even with varying lengths of the respective tube element 10 in the manufacture of tolerance-compliant screw elements 20 easy to manufacture.

Provision can be made for the tubular element by means of the method described so far 10 only roughly deformed or a shape of the screw element 2 is only roughly approximated. Accordingly, it can be provided that the already roughly deformed tubular element 10 one process step or several process steps of the previously described method for producing the screw element 2 is subjected again and / or repeatedly, so that from the tubular element 10 ultimately the desired screw element 2 emerges, the external thread 6 is generated in a step following this method. In particular, it can be provided that a further die is used which has a further mandrel. The further mandrel can have a smaller outer peripheral surface than the mandrel of the first die 28 have, so that in the course of manufacturing the screw element 2 when reshaping the tubular element 10 is enabled, the inner peripheral surface 15 keep shrinking. If using the lower die 28 or by means of a further lower die or by means of several further lower dies the head part 3 of the screw element 2 is formed, in particular when the tubular element is finally deformed 10 it should be provided that the die used in the final forming 28 is thorn-free.

Alternatively or additionally, the mandrel can 29 and / or a thorn 29 opposite, further mandrel is provided and designed accordingly, a tool attack, in particular the tool attack 20 , on the headboard 3 of the screw element 2 train. That means that the tool attack 20 forming mandrel, which can be formed in particular on an upper die, not shown, with a desired contour of the tool attack 20 corresponds, for example, is designed as an external hexagon. Here are a longitudinal extension of the mandrel 29 and a longitudinal extent of the further mandrel is coordinated with one another in such a way that the mandrels produce the screw element 2 do not hinder. Likewise, the die 28 , especially the negative form 30 , be designed to a tool attack, in particular the tool attack 19 , on the headboard 3 train. For example, using the negative form 30 in the 4 shown hexagonal head shape of the head part 3 reached when the negative form 30 , at least along their inner circumferential contour, is designed as an internal hexagon which engages with the tool 19 corresponds.

In particular, it can be provided that an inner diameter of the tubular element 10 or an inner diameter of the screw element 2 cold upsetting, especially by means of the mandrel 29 , is calibrated to a predeterminable or predetermined dimension.

Overall, the invention shows how the particularly stable and mass-efficient screw element 2 Is to be provided, which can be used particularly flexibly and is particularly easy to produce. The tubular element faces the hollow screw mentioned at the beginning 10 and consequently the screw element 2 a corner-free internal cross-section, whereby the screw element 2 is particularly easy to manufacture.

The head shapes of the head part mentioned in this brief 3 and / or types or shapes of the tool attacks 19 . 20 are only to be understood as examples. This means that the screw element according to the invention 2 with head shapes and / or tool attacks customary in the prior art 19 . 20 is to be equipped. So can the headboard 3 have an external hexagon, an external torx, an internal torx, a slot and / or a cross recess, in order to be drivable in a known manner by means of conventional tools.

Will the screw element 2 In production, in particular series production, of motor vehicles, the production or series production is adapted to the new screw element 2 obsolete, since an outer contour of the screw element 2 at least essentially corresponds to that of conventional screws or screw elements. In other words, conventional screws or screw elements are without special measures, that is to say particularly inexpensive, against the screw element according to the invention 2 interchangeable, which means the screw element 2 , in particular without loss of time, can be integrated into an ongoing production or series production of motor vehicles. In this way, by means of the screw element 2 generates an environmental benefit because of the screw element 2 is particularly mass-efficient compared to conventional screws or screw elements. Because a motor vehicle, which with the screw element 2 or several screw elements 2 is particularly light, so that this motor vehicle can then be operated in a particularly fuel-efficient, energy-efficient and low-emission manner.

Furthermore, the external thread 6 Can be generated by already known process steps part of the manufacturing process of the screw element 2 are. That means the external thread 6 for example, can be rolled and / or cut, which is why the external thread 6 and consequently the screw element 2 is particularly easy to manufacture.

With cold upsetting of the pipe element 10 , so that the screw element 2 is the channel element 27 closed on the head side at least to the extent that this is not visible without the aid of optical aids. This means that the channel element is closed at the top 27 can be omitted. It is particularly noted that there is a headrest of the head part 3 is at least substantially identical to a head rest of a head part of a screw element without a channel element. In comparison with a full screw or with the screw element without channel element, there is at least essentially the same pre-tensioning force, which is achieved by means of the screw element 2 recordable or by means of the screw element 2 components to be connected and / or connected is transferable. That with the screw element 2 coaxial with the longitudinal center axis 7 arranged channel element represents a material recess in contrast to a solid screw, but this material recess has only a particularly small influence on the performance of the screw element 2 , Accordingly, the screw element 2 at least essentially as powerful as a screw element 2 without channel element or made of solid material with specified dimensions.

In connection with the external thread 6 It should be pointed out that, as already described, this can be produced using methods known from the prior art, in particular without cutting, for example rolling. As a result, a lossless circular washer, which can be used, for example, as a washer between the head part 3 and one by means of the screw element 2 to be clamped component can be arranged in a manner known per se with the screw element 2 to be brought together. In particular, a last thread turn can be closed and / or a thread pitch smaller than a thickness of the washer or circular washer, so that the washer is effective against loss of the shaft part 4 is secured.

LIST OF REFERENCE NUMBERS

1

Longitudinal extension

2

screw

3

headboard

4

shank part

5

threaded portion

6

external thread

7

Longitudinal central axis

8th

length range

9

Hollow cross section

10

tube element

11

subregion

12

The End

13

opening

14

Hollow cross section

15

Inner circumferential surface

16

expansion area

17

Transition area

18

Transition area

19

tool application

20

tool application

21

intermediate

22

intermediate

23

intermediate

24

intermediate

25

The End

26

tube opening

27

channel element

28

die

29

mandrel

30

negative form

31

Squeeze force

32

forming tool

33

die

34

negative form

d1

diameter

d2

diameter

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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

• DE 10319236 A1 [0005]

Claims (13)

Screw element (2), with a head part (3) and with a shaft part (4) connected to the head part (3) and having a threaded area (5) with an external thread (6), which along its longitudinal direction (1) at least in a length range (8) is hollow and thereby has, at least in the length region (8), a hollow cross-section (9, 14) running along the longitudinal direction (1) of the shaft part (4), characterized in that the head part (3) and the shaft part (4 ) are formed from a tubular element (10) which is formed without cutting at least in a partial area (11) and thereby forms in the partial area (11) the head part (3) produced by the forming, which forms the hollow cross section (9, 14) along the Closes longitudinal direction on the side of the head part. Screw element (2) after Claim 1 , characterized in that the tubular element (10) forming the shaft part (4) and the head part (4) is formed in one piece, whereby the shaft part (4) is formed in one piece with the head part (3). Screw element (2) after Claim 1 or 2 , characterized in that the hollow cross section (9, 14) is free of an angular shape on the inner circumferential side. Screw element (2) according to one of the preceding claims, characterized in that the shaft part (4) has an expansion region (16) which is at least outer-circumferentially thread-free in the longitudinal direction (1) of the shaft part (4) between the head part (3) and the threaded region (5) having. Screw element (2) after Claim 4 , characterized in that the expansion area (16) has a smaller outer circumference than the thread area (5). Screw element (2) after Claim 4 or 5 characterized in that the shaft part (4) has a transition region (17) which is arranged in the longitudinal direction (1) of the sheep part (4) between the stretching region (16) and the head part (3) and which extends in the longitudinal direction (1) of the shaft part ( 4), in particular towards the expansion area (16), tapers. Screw element (2) according to one of the preceding claims, characterized in that the head part (3) has a larger outer circumference than the shaft part (4). Screwing element (2) according to one of the preceding claims, characterized in that the head part (3) has a tool engagement (19, 20), via which the head part (3), in particular in a form-fitting manner, can be coupled to a tool for driving the screwing element (2) is. Method for producing a screw element (2), in which a head part (3) and a shaft part (4) connected to the head part (3) and having a threaded region (5) with an external thread (6), which along its longitudinal direction (1) is hollow at least in one length region (8) and thereby has at least in the length region (8) a hollow cross-section (9, 14) running along the longitudinal direction (1) of the shaft part (4), characterized in that the head part ( 3) and the shaft part (4) are produced from a tubular element (10) which is formed without cutting at least in a partial area (11), as a result of which in the partial area (11) the hollow cross section (9, 14) as a result of the forming along the longitudinal direction (1) on the side of the head part (3) closing head part (3) is produced. Procedure according to Claim 9 , characterized in that the tubular element (10) has the hollow cross section (9, 14) before the forming. Procedure according to Claim 10 , characterized in that the hollow cross section (9, 14) passes through the tubular element (10) along its entire longitudinal direction (1) before the forming. Procedure according to one of the Claims 9 to 11 , characterized by the steps: - providing a die (28) having a mandrel (2); - Placing the tubular element (10) on the mandrel (29) by at least partially inserting the mandrel (29) into the hollow cross section (9, 14) of the tubular element (10); - Forming the tubular element (10) while the tubular element (10) is placed on the mandrel (29), so that the tubular element (10) is held by means of the mandrel (29) during the shaping. Procedure according to one of the Claims 9 to 12 , characterized in that cold forming is carried out as the forming.

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