Stabiliser

Abstract

The invention relates to a stabiliser (20) comprising a bar end that has been reshaped into a stabiliser blade (22) such that the stabiliser (20) comprises: a central portion (24); the stabiliser blade (22); and a transition region (26) between the central portion (24) and the stabiliser blade (22). A hole is introduced into the stabiliser blade by means of laser cutting, or a contour of the stabiliser blade is shaped by means of laser cutting.

Description

[0001] stabilizer

[0002] Description

[0003] The invention relates to the manufacture of stabilizers, in particular stabilizers for motor vehicles with a rod end formed into a stabilizer blade.

[0004] Conventional end machining of a stabilizer bar typically involves the following process flow: The bar ends are first heated inductively (either one side at a time or both sides at a time), for example, to a temperature range of 650–1200°C. The temperature depends on various geometric and customer-specific requirements, such as dimensional accuracy, hardness values, service life requirements, etc. This is followed by mechanical press processing, in which the heated bar end is hot-formed ("flattened") in successive steps to form the stabilizer bar. The formed stabilizer bar is then punched and optionally cut, and finally, the bar surfaces are calibrated for the required flatness and parallelism. Optionally, a bending operation of the formed stabilizer bar is possible between hot-forming and punching / cutting.However, this does not rule out the possibility that the forging process, ie the forming, may also be carried out cold in the future, ie at a temperature below 650°C, in particular at room temperature.

[0005] Currently, the shaping of the flattened stabilizer blade (cutting) and the creation of a hole for the landing gear (punching) are both performed using a mechanical cutting process. However, the tools for cutting and punching are expensive to purchase and expensive to maintain, for example, due to the replacement of spare or wear parts. In particular, the cutting surface of the tool must be replaced regularly, as it wears out and the quality of the cut deteriorates with increasing service life. For example, the use of tools can cause unwanted burrs to form on the cutting surfaces. The likelihood of this increases with the service life of the cutting surface.

[0006] Due to the formation of burrs and bending caused by mechanical friction during mechanical punching / cutting, calibration is also necessary, or at least advantageous. Calibration involves renewed pressing of the screwing surfaces against each other on the already flattened and punched stabilizer blade. Calibration punches are used, which ensure the necessary customer requirements regarding flatness and parallelism of the blade surfaces by pressing them together on both sides. This prevents the screws from becoming loose due to, for example, settling behavior or a "slanted" connection due to insufficient parallelism. Optionally, the burr around the bottom of the hole created during punching can be pressed back into place with the help of a cone and reduced / prevented.

[0007] The object of the present invention is therefore to create an improved concept for stabilizers.

[0008] This problem is solved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

[0009] Embodiments show a stabilizer with a rod end formed into a stabilizer blade, so that the stabilizer has a central section, the stabilizer blade, and a transition region between the central section and the stabilizer blade. The stabilizer can comprise a (spring) steel or consist predominantly of a steel, in particular a spring steel. Suitable spring steels include, for example, 26MnB5, 34MnB5, and 40MnB5. Generally, however, any material that can be cut using a laser and meets the mechanical requirements of a stabilizer is suitable. Advantageously, a laser cutting optic is used for cutting / punching.

[0010] A hole is created in the stabilizer blade using laser cutting (as opposed to mechanical punching). Additionally or alternatively, a contour of the stabilizer blade is formed using laser cutting (as opposed to mechanical cutting).

[0011] The idea is to replace the mechanical process of punching and / or cutting with a laser process. This guarantees a consistent cutting pattern over the entire service life and avoids the formation of burrs, for example. Furthermore, the process is easier to automate using a laser than with a tool. In addition, a certain overhang of the blade end is necessary for mechanical cutting in order to achieve a straight cut edge. The laser can therefore reduce waste. This makes production more cost-effective. Furthermore, when punching or cutting with a laser, there is no need to calibrate the stabilizer blade. In this case, the formation of burrs is irrelevant for further processing. This means that the screw-on surface is flat after laser cutting, ie it does not have any elevations that could be detrimental to later assembly, e.g. due to a burr.

[0012] In exemplary embodiments, the stabilizer has a weld seam in the region of the transition area or the stabilizer blade. The weld seam is particularly advantageous when using a tubular stabilizer as the stabilizer. The tubular stabilizer has a tubular section as the center section and a tubular end as the rod end.

[0013] Studies have shown that the blade ends of a pipe stabilizer are generally almost gap-free (a few pm) after the hot forming process (“flattening”) and are therefore almost liquid-tight. However, without a material bond, capillary action cannot be avoided, which means that (negligible) small amounts of moisture can still penetrate the pipe stabilizer. The mechanical and tool-dependent follow-up process of conventional punching / cutting promotes the pulling apart of the two blade surfaces due to friction effects, which increases the gap between the two blade surfaces and further reduces the tightness. The consequences of a gap are, on the one hand, the possible ingress of corrosive fluids, for example water, other process media such as pretreatment in the painting process, gases such as oxygen, etc., which later represent starting points for corrosion formation on the inner surface of the stabilizer.Component failure is thus favored by any corrosion-related material damage. Furthermore, further quality defects occur during the painting process, as escaping fluids can negatively affect the coating at the blade end during powder coating and baking. Consequently, the penetration and escape of (corrosive) fluids into and from the uncoated pipe area at the blade end must be prevented.

[0014] Various sealing methods are already known. For example, US Pat. No. 6,547,894 B1 discloses the introduction of a fusion welding powder such as sodium tetraborate between the blade surfaces. Upon heating, the powder melts and bonds the two formed, flattened blade surfaces together. However, it has been found that the application of the fusion welding powder, and thus the entire process, cannot be reliably automated. Furthermore, sodium tetraborate, due to its boron content, is demonstrably hazardous to human health. Alternative methods for sealing the pipe stabilizer have so far failed to reliably ensure a tight seal.

[0015] By using a weld in the transition area or stabilizer blade, gas and / or fluid exchange between the inner pipe (i.e., the pipe section) and the environment is avoided. In particular, the weld is formed in the absence of a filler metal.

[0016] Welding consumables are typically added in the form of powders, rods, or wires, melted, and solidified in the joint between the joining partners to create the connection. Without a welding consumable, the weld is created solely by melting the materials—here, the two blade surfaces—so that the two materials fuse together.

[0017] This eliminates the difficult-to-automate step of applying the welding consumable. Welding consumables must be distinguished from welding aids such as shielding gases, fluxes, vacuum (e.g., in electron beam welding), pastes, or welding powder, which facilitate welding or even make it possible in the first place. Welding powder is used, for example, in submerged-arc welding and should not be confused with fusion welding powder as a welding consumable. Examples of welding processes that are used without welding consumables include deep penetration welding and deep penetration welding.Laser deep penetration welding (laser welding for short), heat conduction welding, resistance welding, laser-MIG hybrid welding, laser vacuum welding, laser transmission welding, gas fusion welding, manual arc welding, gas shielded arc welding, submerged arc welding, electron beam welding, forge welding, cold pressure welding, friction welding, explosive welding, electromagnetic pulse welding, diffusion welding, MBP welding, arc stud welding, or build-up welding. This means that the weld seam can be created using one of the aforementioned welding processes or any combination thereof.

[0018] Of course, it is also possible to provide multiple welds instead of a single weld. Furthermore, the weld can be designed in various variants, the designs of which vary according to a wide variety of criteria. The following criteria are examples: arrangement or position (position of the weld(s) on the sheet / arrangement of the welds relative to each other), shape (weld width, weld height, straight weld, semicircular weld, wavy weld, arbitrarily shaped weld, etc.), design type (single-layer or multi-layer weld).

[0019] This allows for a manual or automated welding process for the tube end of the pipe stabilizer. The two blade surfaces are completely bonded and tightly connected in the direction of the non-formed pipe cross-section. This also eliminates quality defects due to poor paint adhesion caused by fluids that may escape from the pipe stabilizer during the painting process. Furthermore, the addition of preservatives to the pipe stabilizer to protect the inner surface from corrosion is no longer necessary. Furthermore, the welding process offers the advantage that the pipe stabilizer remains fluid-tight even under negative or positive pressure conditions. This is advantageous, for example, when ambient temperatures fluctuate during operation or during a tempering process during production.During the tempering process, the tube stabilizer is quenched in a quenching medium after heating, which quickly creates large temperature and thus pressure differences due to the trapped air volume in the tube stabilizer. Even under these conditions, the tube stabilizer must remain fluid-tight.

[0020] Another beneficial effect of welding is the better stress distribution in the stabilizer blade compared to an unwelded stabilizer blade. This offers the possibility of saving material while maintaining the same service life or extending the service life of the tubular stabilizer.

[0021] The weld seam is preferably formed by laser welding. Laser welding has the advantage that the energy is introduced into the material by means of a laser beam focused by an optics. By automatically changing the optics, weld seams of different widths and depths can be created, for example. Furthermore, the cycle times, i.e. the time taken to produce the weld seam, can be adjusted if the energy acts on the material in a more or less focused manner. The laser power is also adjustable and can be adapted, for example, to different sheet thicknesses. Thus, with knowledge of the pipe stabilizer to be welded, the weld seam can be automatically adapted, for example, to a material or a wall thickness of the pipe stabilizer. The automated steps described in this disclosure can be carried out by a processing unit, i.e. a computer.

[0022] In conjunction with laser cutting, it is possible to use the same laser (=energy source) for laser welding. However, it may be advantageous to use different optics to focus the light in order to switch between laser welding and laser cutting. The optics can be arranged in parallel on the laser, i.e., on one light source, and controlled by software and / or hardware switching. The optics can be connected to the light source via two optical fibers. This step is also easily automated. However, it is also possible to use different lasers.

[0023] In exemplary embodiments, the weld seam is made on the head side, preferably across the entire width of the stabilizer blade. This means that in order to melt both blade surfaces, it is not necessary to first penetrate the upper blade surface in order to liquefy material from the lower blade surface. Both blade surfaces are visible on the head side and can be melted simultaneously. This means that less energy is required for welding and the welding process is completed more quickly. However, it is advantageous if an opening (also referred to as a bore) through the stabilizer blade, which can be used to attach the tubular stabilizer to the landing gear, also has a further weld seam running laterally (preferably completely) around the entire circumference and is arranged within the opening. This means that the cutting gap of the opening can be sealed.If all open areas of the pipe stabilizer are completely sealed at one end, no liquid can penetrate, at least from one side. Advantageously, both sides of the pipe stabilizer are sealed accordingly by the weld seam. For example, both ends of the pipe stabilizer are designed symmetrically or similarly.

[0024] Additionally or alternatively, the opening through the stabilizer blade can be sealed from the transition area or from the pipe section. This can be achieved, for example, by means of a weld seam laterally applied to the stabilizer blade or the transition area. In this case, the weld seam is located between the pipe section and the opening. The weld seam preferably extends across the entire width of the stabilizer blade or the transition area. However, it is also possible to seal the blade end using several weld seams, although not all weld seams need to extend across the entire width of the stabilizer blade. For example, the hole can be sealed all the way around the inside with a weld seam.

[0025] In order to avoid a protruding weld seam in the hole or on any outer side of the stabilizer blade, it can be advantageous not to make the hole or the trim in general identically continuous, but for example to make it conical or with a step around the parting line of the blade surfaces. This type of shape can be created more easily with a laser than with a tool. This creates space for the weld seam in the range of a few tenths of a millimeter without violating the tolerance requirements, so that, for example, the screw connection is not impaired. Additionally or alternatively, the area of ​​the later weld seam in the area of ​​the parting line or the surface of the stabilizer blade can be subsequently machined, for example with a laser, in order to remove material for the weld seam and to prevent the weld seam from protruding. A laser is also suitable for cutting and / or punching the stabilizer blade.However, it is then optional to choose a different optics or a different power or a different parameter of the laser.

[0026] In general, it is possible to create at least one weld seam either between the transition area and the aperture, between the blade end and the aperture, around the aperture, or directly around the cut gap of the aperture or at the end trim, in various geometries and seam widths and other designs, individually, multiple times, or in any combination. This approach offers the advantage of a materially bonded connection between the two pressed blade surfaces, thus ensuring a completely sealed stabilizer end.

[0027] In further embodiments, the laser can also be used for identifying the stabilizer, particularly by engraving it. This enables the stabilizer to be clearly traced. A combination of numbers and / or letters, for example, can be used as the identifying mark. For this purpose, it may be advantageous to use a different lens (e.g., an engraving lens) for the laser than for cutting and / or to use a lower power to control the laser.

[0028] In exemplary embodiments, the contour of the stabilizer blade and / or the hole has an undercut, in particular a beveled cut surface in the hole or on the contour of the stabilizer blade. This means that the hole is designed, for example, as a cone. The cut surface can be beveled, i.e., not at a right angle to the blade surface. This can be achieved, for example, by an orientation of the laser that deviates from a 90° orientation, i.e., the perpendicular incidence of the laser beam on the cut surface. Furthermore, a method for producing a cold-bent stabilizer from a rod is disclosed, comprising the following steps: a) forging the rod or a tempered stabilizer to obtain a forged rod or a forged stabilizer; b) bending the rod or the forged rod to obtain a stabilizer; c) tempering the bent rod to obtain a tempered stabilizer.Forging the tube comprises the following steps: a1) flattening one end of the rod so that the forged rod has a central section, a stabilizer blade, and a transition region between the central section and the stabilizer blade; and a1a) cutting a hole in the stabilizer blade using laser cutting and / or a1b) shaping a contour of the stabilizer blade using laser cutting. Typically, when producing a cold-bent tubular stabilizer, a tube is used as the rod. Otherwise, a solid rod is typically used as the rod. However, it is also possible to hot-bend tubes and cold-bend solid rods.

[0029] Examples of embodiments demonstrate that the process eliminates the need for a process step for smoothing or reducing burrs after laser cutting. This means that no subsequent calibration of the blade surfaces is necessary, since laser cutting does not result in significant burr formation. This also results in improved paintability of the stabilizer from the outset, since a smoothed or reduced burr still has an increased likelihood of edge corrosion, for example, if tool wear is not detected in time. Furthermore, the use of the laser achieves improved process stability compared to conventional, mechanical punching / cutting, since the laser exhibits significantly lower wear / aging than mechanical tools.

[0030] In exemplary embodiments, the forging of the tube of a tube stabilizer additionally comprises the following further step: a2) Creating a weld seam in the region of the transition area or the stabilizer blade to seal the tube section as the central section against fluid and / or gas exchange with the environment. Optionally, the forging can include further process steps after flattening and before welding, such as punching and / or cutting the stabilizer blade using laser cutting.

[0031] The creation of the weld seam in step a2) and the creation of the hole in step a1a) or the shaping of the contour in step a1b) can be performed with the same laser. The optics of the laser system can be changed between the steps to use the laser either for cutting or welding. The order of the welding steps a2) and cutting (a1a and a1b) is interchangeable. However, it is also possible to perform cutting and welding in parallel, especially with different lasers / light sources.

[0032] For example, process steps a), b), and c) can be performed in alphabetical order, i.e., in the process sequence a), b), and c). Alternatively, process steps a), b), and c) can be performed in the process sequence b), c), a).

[0033] Cold-bent tubular stabilizers are currently typically piece-hardened or batch-hardened after forming, and then the stabilizer blades are forged, i.e., particularly the ends are flattened (see also the description in the introductory section). This results in lower efficiency for forging, particularly due to the complex handling of the already bent stabilizers.

[0034] By reliably sealing the tube ends, it is now possible to modify the process flow so that forging, including flattening and sealing the tube stabilizer end flattened into the stabilizer blade, can take place before quenching and tempering, and thus also before bending the tube stabilizer (process sequence: a), b), c)). The sealed end of the tube stabilizer reliably prevents the penetration of the quenching medium during quenching and tempering. Significant efficiency improvements, particularly in the forging process, are expected from this change in the process. Instead of the laborious handling of bent, quenched and tempered tubes, usually using a (usually stationary) industrial robot, the straight tube can be fed to the various forging stages in parallel via a linear transfer system. Closing can also be integrated into this process step, for example, in the form of a welding process.If it turns out that there are other processes that enable reliable, automated sealing of the pipe ends, these may be just as suitable as the welding process.

[0035] Sealing the pipe ends also has advantages for the classic cold bending process (process sequence b), c), a)). This prevents corrosive fluids, such as process media used in pretreatment during the painting process, from penetrating the pipe stabilizer when installed in the vehicle or during the subsequent manufacturing process.

[0036] Optionally, the method further comprises step d) blasting the tempered stabilizer to obtain a blasted stabilizer. Blasting, for example, by shot peening, adjusts the compressive residual stresses in the surface. Furthermore, the surface can be roughened so that, in a further optional step e) painting the blasted stabilizer to obtain a painted stabilizer, the paint adheres better to the stabilizer.

[0037] In exemplary embodiments, the stabilizer has a temperature at the start of the creation of the weld seam in step a2) that is at least 20°C, preferably at least 50°C higher than the ambient temperature. In particular, the stabilizer has a temperature of at least 100°C, at least 175°C or at least 250°C. It has been found that the heat of the stabilizer has a positive effect on the subsequent welding. The positive effect relates, for example, to the speed with which the weld seam can be created and / or to the energy required to create the weld seam and / or to the grade, i.e. the quality, of the weld seam. For example, this can reduce the reject rate of the stabilizers during production due to leaky weld seams. The temperature of the stabilizer can be adjusted by heating in a separate process step, e.g. by means of conductive heating or in a furnace or by means of inductive heating.Additionally or alternatively, it is possible to utilize the residual heat from the previous end processing of the stabilizer. Especially by utilizing this residual heat, it is also possible for the stabilizer sheet to have temperatures significantly higher than 250°C, for example, more than 350°C, more than 400°C, or more than 450°C. The latter is obviously advantageous, as it eliminates the need to supply additional energy (heat) that is not required anyway. However, it is then important to ensure rapid processing of the stabilizers in order to utilize the residual heat generated during hot forming until welding.

[0038] Further optionally, after the creation of the weld seam in step a2), a step a3) can be provided, which includes a thermal post-treatment of at least an area around the weld seam. This means that a thermal post-treatment of the sheet or at least the heat-affected zone can be performed after the welding process. This thermal post-treatment can counteract any possible structural changes caused by welding.

[0039] Optionally, the blade can be mechanically finished after the welding process. For example, the side, end, and blade surfaces can be adjusted in a subsequent process, e.g., by cutting and / or grinding the edges.

[0040] The forging process flow can consist of the following steps: Flattening the bar end into a stabilizer blade or

[0041] Pipe stabilizer blade, optional blade bending, punching of the blade and optional trimming of the blade surfaces (i.e. in particular the edges of the blade ends), (laser) welding.

[0042] Furthermore, a method for producing a hot-bent stabilizer is disclosed, comprising the following steps: a) forging a bar to obtain a forged bar, b) heating the forged bar to a temperature above the austenitizing temperature of the bar to obtain a heated bar, c) bending the heated bar to obtain a bent bar in the shape of the stabilizer; d) quenching the bent bar to obtain a hardened, bent bar; e) tempering the hardened, bent bar to obtain the stabilizer; wherein the forging of the bar comprises the following steps: a1) flattening one end of the bar such that the forged bar has a central section, a stabilizer blade, and a transition region between the central section and the stabilizer blade; and a1a) making a hole in the stabilizer blade by means of laser cutting and / or a1b) shaping a contour of the stabilizer blade by means of laser cutting.The process can also be carried out specifically for pipe stabilizers with a pipe as a rod.

[0043] The embodiments of the method for producing a cold-bent stabilizer can be transferred to the method for producing a hot-bent stabilizer.

[0044] For hot-bent stabilizers, it is common practice to forge them prior to forming. The resulting blade ends can then be directly laser-cut to create the hole and / or shape the contour. During hot bending, the stabilizer is tempered and quenched in parallel with the bending process. The stabilizers are bent while heated above the austenitizing temperature, then quenched, for example, in an oil bath, and then tempered, for example, in a furnace. The efficiency of the forging process is significantly higher.

[0045] During both cold bending and hot bending, it is advantageous if the stabilizer blades are sealed in a fluid-tight manner. This means that in both cases the quenching required after tempering can take place after forging without the quenching medium penetrating the tube stabilizer and potentially causing corrosion. However, even if a process flow is selected in which tempering (particularly during cold bending) takes place before forging, corrosive fluids such as moisture can subsequently penetrate into the interior of the stabilizer, even when installed, and this can lead to corrosion. However, pre-treatment for painting, which is a downstream process flow, typically uses corrosive fluids that can penetrate into the interior of the tube stabilizer if it is not sealed in a fluid-tight manner.

[0046] It should be noted that the terms "hot forming" and "hot bending" represent different process steps. Hot forming involves the production of the blade end(s), or flattening. The blade end is the connection point between the stabilizer bar and the chassis. Hot bending creates the entire shape of the stabilizer bar, i.e., adapting the shape of the stabilizer bar to the specific vehicle.

[0047] In general, the manufacturing process for stabilizers includes, for example, the following process steps: forging, bending, tempering, optional blasting, optional painting. Furthermore, it is possible to carry out further intermediate process steps, such as internal blasting or internal preservation. In principle, however, internal preservation, i.e. corrosion protection from the inside, by welding the blade ends can be dispensed with, as no corrosive media can penetrate the stabilizer. For example, it can be advantageous to carry out internal blasting before forging in order to achieve a better weld seam. As the area of ​​the future stabilizer blade is cleaned and the weld seam is less prone to defects, i.e. the probability of leaks in the weld seam is reduced. This increases process stability during the welding process. Furthermore, welding a previously cleaned stabilizer blade orWelding a generally clean stabilizer blade requires less energy than welding an uncleaned stabilizer blade.

[0048] Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. They show:

[0049] Fig. 1: a representation of a tubular stabilizer with a weld seam in the stabilizer blade in three different views, wherein Fig. 1a shows a perspective representation, Fig. 1b a side view and Fig. 1c a scanning microscope representation of the stabilizer blade in longitudinal section;

[0050] Fig. 2: the representation from Fig. 1a and Fig. 1b, wherein Fig. 2a, Fig. 2b, Fig. 2c, Fig. 2d, Fig. 2e and Fig. 2f each schematically show different arrangements of weld seams;

[0051] Fig. 3: a flow chart illustrating various process flows, wherein Fig. 3a and Fig. 3b each show different process flows for producing the stabilizer, Fig. 3c discloses a process flow of forging with welding and Fig. 3d discloses a process flow for hot bending;

[0052] Fig. 4: a schematic perspective view of a stabilizer.

[0053] Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally equivalent or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0054] Fig. 1 shows in Fig. 1a, Fig. 1b and Fig. 1c each different views of an end region of a tubular stabilizer 20. The tubular stabilizer comprises a stabilizer blade 22, a tubular section 24 and a transition region 26 which is arranged between the stabilizer blade 22 and the tubular section 24. In the region of the stabilizer blade 22, or additionally or alternatively also in the region of the transition region 24, a weld seam 28 is formed in order to protect the tubular section against the ingress of moisture. Furthermore, an opening 30 is formed in the stabilizer blade. The opening, also referred to as a hole, is created by laser cutting. For the sake of simplicity, the process of creating the hole is also referred to as piercing when created by laser. Furthermore, a small gap 34 between the two blade surfaces of the blade end 22 is visible on the end face 32 and in the opening 30.

[0055] The blade end 22 of the tubular stabilizer 20 can be designed in various ways. In addition to the curved contour (round cut) and flat shape shown, the stabilizer blade can also have a kinked or curved shape, for example. The contour of the blade can also have various characteristics, for example an angular contour or a curved, for example slightly S-shaped or C-shaped end face. The contour is formed by laser cutting. From a purely external perspective, the mechanical contour is hardly distinguishable from a laser-cut contour, particularly when using a new cutting surface of the tool. Only the gap 34 between the blade surfaces is smaller. Furthermore, burr formation is reduced during laser cutting, and in particular macroscopically visible burr formation is largely avoided.However, microscopically, for example under a scanning electron microscope, the differences between a mechanically formed contour and a contour formed by laser cutting are visible.

[0056] Fig. 2 shows various options for forming the weld seam 28 based on the illustrations in Fig. 1a and Fig. 1b. The weld seams 28 are hatched and shown only schematically. Fig. 2a discloses the weld seam 28 in the stabilizer blade 22 between the opening 30 and the transition region 26. The weld seam 28 is formed laterally on the stabilizer blade. Fig. 2b discloses two weld seams 28, 28'. The first weld seam 28 closes the stabilizer blade 22 at the head end. The second weld seam 28' is arranged laterally circumferentially within the opening 30.

[0057] Fig. 2c, like Fig. 2a, discloses a weld seam 28 in the stabilizer blade 22 between the opening 30 and the transition region 26, but here the weld seam 28 is inclined. Fig. 2d discloses a weld seam 28 consisting of a closed section, consisting of four sections, for example. Thus, the opening 30 is sealed off from the tubular section 24 of the tubular stabilizer. Furthermore, it is important to ensure that at least one section of the section seals the entire width of the stabilizer blade 22. This is achieved in Fig. 2d by the weld seam 28 between the opening 30 and the transition region 26.

[0058] Fig. 2e and Fig. 2f each disclose a double weld seam 28, 28'. In Fig. 2e, the second weld seam 28' is arranged in the transition region 26, while the first weld seam 28 is arranged in the stabilizer blade 22. Furthermore, the weld seams 28, 28' are curved. Fig. 2f discloses straight, parallel weld seams 28, 28' in the stabilizer blade 22.

[0059] Fig. 3a and Fig. 3b show the process steps of forging 50, bending 52, tempering 54, blasting 56, and painting 58. With the fluid-tight or at least liquid-tight sealed, especially welded, tube stabilizers, the process steps can be interchanged almost arbitrarily. However, it is advisable to perform blasting 56 and painting 58 consecutively at the end of the process to protect the paint layer. Furthermore, blasting should be performed after 56 and tempering 54. There are no further restrictions regarding the selection of the sequence of the process steps.

[0060] Fig. 3a now discloses a process sequence that enables a fast cycle time in the production of pipe stabilizers. First, a pipe made of steel or spring steel is forged (step 50) to obtain a forged pipe. The forging process sequence is explained in Fig. 3c. The forged pipe is then bent (step 52) so that the pipe takes on the shape of the pipe stabilizer. The pipe is bent by cold bending, i.e. at a temperature of maximum 150°C, typically maximum 100°C, usually maximum 50°C. The forged pipe is quenched and tempered in step 54 to obtain a quenched and tempered pipe stabilizer. Tempering gives the pipe stabilizer its desired strength. Optionally, after tempering in step 56, the quenched and tempered pipe stabilizer is (shot) peened. Shot peening sets residual compressive stresses in the surface.The tempered or blasted tube stabilizer can also be painted optionally. This coating prevents, for example, external corrosion of the tube stabilizer.

[0061] Fig. 3b shows a different sequence of process steps than Fig. 3a. Here, the tube is first bent (step 52) and then tempered. After tempering, the tempered tube is forged. Through forging, the tube stabilizer receives the flattened end into a stabilizer blade. Optionally, steps 56 and / or 58 also follow here. The description of the process steps from Fig. 3a applies analogously here.

[0062] Further process steps can be performed in the process sequences shown in Fig. 3a and Fig. 3b depending on customer requirements or technical requirements. For example, it is possible to blast the tube from the inside before forging in step 50. This also adjusts the residual compressive stresses on the inner surface of the tube, at least in some areas. Furthermore, it is possible to use a previously tempered tube or to omit the tempering process (with a suitable material selection), so that process step 54 is obsolete in the embodiments shown in Fig. 3a and Fig. 3b.

[0063] Fig. 3c now discloses the process steps 50 for forging the tubular stabilizer or the steel tube. The forging comprises flattening (step 60) one end of the tube (or both tube ends) so that the forged tube has a tube section, a stabilizer blade (or two stabilizer blades), and a transition region (or two transition regions) between the tube section and the stabilizer blade. Optionally, the blade bending then takes place in step 62. By bending the blade, the stabilizer blade can be given a shape that deviates from the flat (solely flattened) shape. In step 64, the piercing (or creation of the opening) takes place. Optionally, the flattened end of the tubular stabilizer is also trimmed to obtain the desired contour of the blade end. Trimming can take place in the same process step as piercing or separately.

[0064] In step 68, the weld seam is created in the transition area or stabilizer blade to protect the pipe section from moisture penetration. Steps 62 (blade bending), 64 (punching), and 68 (welding) therefore take place after flattening in step 60.

[0065] Fig. 3d discloses a process sequence for hot bending the tube stabilizer. In step 50, the (still straight) tube is first forged, for example, according to the process steps described in Fig. 3c. Steps 52 (hot bending) and 54 (quenching and tempering) then follow in parallel. Hot bending typically occurs above the austenitizing temperature. Quenching and tempering involves hardening in a quenching medium and subsequent tempering after heating. This is followed by steps 56 (blasting) and 58 (painting) as already described with reference to Fig. 3a and Fig. 3b. The process steps were described with reference to a tube stabilizer, but are also applicable to a stabilizer made from a solid rod, whereby the fluid-tight sealing can be neglected in this case, since the solid rod has no cavity into which the fluid can penetrate.

[0066] Fig. 4 shows a schematic representation of a stabilizer 20. The stabilizer 20 has a stabilizer blade 22, 22' at each end. The stabilizer blades 22, 22' each have an opening 30, 30', i.e., a hole. Between the two stabilizer blades 22, 22' is the central section, which in the case of a tubular stabilizer is referred to as the tubular section 24. The stabilizer 20 is typically attached to the (motor) vehicle with two clamps.

[0067] Although some aspects have been described in connection with a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device.

[0068] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein. List of Reference Symbols:

[0069] 20 Pipe stabilizer / stabilizer

[0070] 22 Stabilizer blade 24 Pipe section / center section

[0071] 26 Transition area

[0072] 28 Weld seam

[0073] 30 Breakthrough

[0074] 32 Head side of the stabilizer blade 50ff Process steps

Claims

Patent claims 1 . Stabilizer (20) with the following features: - a rod end formed into a stabilizer blade (22), so that the stabilizer (20) has a central section (24), the stabilizer blade (22) and a transition region (26) between the central section (24) and the stabilizer blade (22), - wherein a hole is made in the stabilizer blade by laser cutting or wherein a contour of the stabilizer blade is formed by laser cutting.

2. Stabilizer (20) according to claim 1, wherein the stabilizer has the absence of a smoothed or reduced burr in the region of the contour and / or the hole of the stabilizer blade.

3. Stabilizer (20) according to one of the preceding claims, wherein the stabilizer has a distinctive marking of the stabilizer applied by means of a laser.

4. Stabilizer (20) according to one of the preceding claims, wherein the contour of the stabilizer blade and / or the hole has an undercut, in particular an oblique cut surface.

5. Stabilizer (20) according to one of the preceding claims, wherein the stabilizer is a tubular stabilizer, wherein the tubular stabilizer has a weld seam (28) in the region of the transition region (26) or the stabilizer blade (22) in order to avoid gas and / or liquid exchange between the tubular section (24) as the central section and the environment, in particular wherein the weld seam (28) is formed in the absence of a welding filler material.

6. Stabilizer (20) according to claim 5, wherein the weld seam (28) is formed by laser welding.

7. Stabilizer (20) according to one of claims 5 or 6, wherein the weld seam (28) is formed on the head side (32) of the stabilizer blade (22).

8. Stabilizer (20) according to one of claims 5 to 7, wherein the stabilizer blade (22) has an opening (30), the opening being sealed by means of the weld seam (28) with respect to the transition region (26) or the tube section (24).

9. Stabilizer (20) according to one of claims 5 to 8, wherein the stabilizer blade (22) has an opening (30), wherein the tubular stabilizer (30) has a further weld seam (28'), wherein the further weld seam is arranged laterally circumferentially within the opening (30).

10. Stabilizer (20) according to one of claims 5, 6 or 8, wherein the weld seam (28) is made laterally on the stabilizer blade (22) or the transition region (26), the weld seam (22) being arranged between the tube section (24) and the opening (30). 11 . A method for producing a cold-bent stabilizer from a bar, comprising the following steps: a) forging (50) the bar or a tempered stabilizer to obtain a forged bar or a forged stabilizer; b) bending (52) the bar or the forged bar to obtain a stabilizer; c) tempering (54) the bent bar to obtain a tempered stabilizer; - wherein the forging (50) of the tube comprises the following steps: a1) flattening (60) one end of the rod so that the forged rod has a central section (24), a stabilizer blade (22) and a transition region (26) between the central section (24) and the stabilizer blade (22); and a1a) making a hole in the stabilizer blade by means of laser cutting and / or a1b) shaping a contour of the stabilizer blade by means of laser cutting.

12. The method according to claim 11, which method comprises the absence of a process step for smoothing or reducing a burr after laser cutting.

13. A method according to any one of claims 11 or 12, wherein the method comprises applying a distinctive mark to the stabilizer by means of a laser.

14. The method according to any one of claims 11 to 13, wherein the hole is formed in step a1a) and / or the contour of the stabilizer blade is formed in step a1b) with an undercut.

15. The method according to any one of claims 11 to 14, wherein the forging (50) of the tube of a tube stabilizer comprises the following further step: a2) creating (68) a weld seam (28) in the region of the transition region (26) or the stabilizer blade (22) in order to seal the tube section (24) as a central section against liquid and / or gas exchange with the environment.

16. The method according to claim 15, wherein the creation of the weld seam in step a2) and the introduction of the hole in step a1a) or the shaping of the contour in step a1b) are carried out with the same laser, wherein between the steps an optical system of the laser system is changed in order to use the laser either for cutting or for welding.

17. A method according to any one of claims 11 to 16, comprising the further step of: d) blasting (56) the tempered stabilizer after steps a) to c) to obtain a blasted stabilizer.

18. The method according to claim 17, comprising the further step of: e) painting (58) the blasted stabilizer after step d) to obtain a painted stabilizer.

19. The method according to any one of claims 15 to 18, wherein the stabilizer has a temperature at the beginning of the creation of the weld in step a2) which is at least 20°C higher than the ambient temperature.

20. The method according to claim 19, wherein the temperature of the stabilizer remains in the stabilizer as residual heat of the flattening in step a1).

21. Method according to one of claims 15 to 20, wherein the method, after the creation of the weld seam in step a2), provides a step a3) which comprises a thermal post-treatment of at least one region around the weld seam.

22. Method according to one of claims 15 to 21, wherein the method steps a) to c) are carried out in the said alphabetical order.

23. The method according to any one of claims 15 to 22, wherein the method steps a) to c) are carried out in the following order: b), c), a).

24. A method for producing a hot-bent stabilizer comprising the following steps: - a) forging a rod to obtain a forged rod; - b) heating the forged bar to a temperature above the austenitizing temperature of the bar to obtain a heated bar; - c) bending the heated rod to obtain a bent rod in the shape of the stabilizer; - d) quenching the bent bar to obtain a hardened, bent bar; - e) tempering the hardened, bent rod to obtain the stabilizer; - wherein the forging (50) of the rod comprises the following steps: -a1) flattening (60) one end of the rod so that the forged rod has a central section (24), a stabilizer blade (22) and a transition region (26) between the central section (24) and the stabilizer blade (22); and - a1a) Making a hole in the stabilizer blade by laser cutting and / or - al b) forming a contour of the stabilizer blade by laser cutting.

Images