Stabilizer for motor vehicles

Abstract

Method for producing a sealed stabilizer (1) having a hollow profile section (2), comprising at least the following steps: -Bending and hardening a hollow profile section (2) into its final shape -Introducing an intumescent material (5) into the end(s) at a predetermined distance from this end(s) -Flattening and punching the flattened end -Heating the end region with introduced intumescent material (5) to at least the activation temperature of the intumescent material (5).

Description

[0001] The invention relates to a method for producing a stabilizer for motor vehicles, at least comprising a hollow profile section made of metal with at least one end sealed and flattened relative to the hollow profile section.

[0002] Stabilizers used today in motor vehicle construction usually consist of a hollow profile section made of metal and are used to counteract the compression of a wheel on one side and the resulting rolling of a vehicle when cornering and over uneven roads, thus reducing this rolling.

[0003] For this purpose, the stabilizer is indirectly connected to the wheel suspension of one axle.

[0004] To ensure a long service life for such stabilizers, it is common practice to coat the inner surface of the respective hollow profile with a corrosion inhibitor, such as anti-corrosive oil. This largely prevents corrosion of the hollow profile section from the inside out, and in the long term.

[0005] Furthermore, it is known and common practice to treat the hollow profile section, including the flattened end and, if applicable, the perforation, to increase the service life of such a stabilizer. Such treatment can be performed, for example, by surface hardening blasting and / or by a coating process, such as any type of chemical pretreatment of the metal surface, zinc phosphating, iron phosphating, or a coating using nanoceramics. Stabilizers are also coated with a powder coating according to the state of the art. Pretreatment involves spraying, dipping, or similar coating methods known per se.

[0006] In addition, the large temperature differences in such a coating system, both in the spray and dipping processes and in the associated furnaces, can lead to the entry and exit of various substances, such as liquids or ambient air, which can lead to defects and rejects during production. These defects can be avoided, in particular, by completely sealing the hollow profile section from the flattened end.

[0007] A stabilizer for motor vehicles of the type mentioned above is known, for example, from US 4836516 A.

[0008] In the prior art, a generic stabilizer and a method for producing the same are known from DE 10 2005 019 469 A1, in which an insert is co-formed in the flattened end to seal the end of the hollow profile section.

[0009] The seal directly in the area of ​​the flattened end with perforation is subject to both temperature fluctuations and movements when the stabilizer is in use, which can cause damage to a seal arranged in this area and, after damage, allow ambient air or liquids from the environment to penetrate into the interior of the hollow profile section.

[0010] Furthermore, the subsequent perforation of the stabilizer in the flattening area by the punching indentation leads to renewed widening and leakage of the end area, i.e. in the area of ​​the flattening opening and the perforation.

[0011] Such sealing has therefore often proven to be unusable in practice.

[0012] Based on the prior art mentioned at the outset, the object of the present invention is to provide a method for producing a stabilizer of the type mentioned at the outset, in which the end region is effectively sealed, in which the seal ensures, even during subsequent heat treatment, that no liquid or ambient air gets into or out of the hollow profile section, which is inexpensive and easy to manufacture and has a long service life.

[0013] The use of an intumescent material to seal the area of ​​the hollow profile section immediately adjacent to the flattened end represents a simple, durable, and extremely efficient way of sealing this area without having to accept a significant increase in weight. Such an intumescent material can also be used if the inner surface of the hollow profile section has been previously treated with a corrosion inhibitor, such as a corrosion protection oil, since the intumescent material may even form a bond with the corrosion protection oil used and, despite the oil film on the inner surface of the hollow profile section, effectively seals against it and effectively prevents the penetration of ambient air or liquids into the interior of the hollow profile section.

[0014] Furthermore, the expansion of the intumescent material after its activation by heating ensures complete filling of the area directly or almost directly adjacent to the flattened end. After its activation by heating, the intumescent material expands wherever it finds space. Thus, expansion can occur right up to the flattened end and fill the entire cross-section of the hollow profile section. If the space in the direction of the flattened end is limited by the flattened end during inflation, further expansion will continue in the direction of the area of ​​the hollow profile section opposite the flattened end.

[0015] The use of such an intumescent material for sealing also enables various subsequent processing operations, both on the flattened end and on the outer surface of the hollow profile section. This means that, for example, subsequent heat treatment, such as powder coating or treatment using a spray or dip process, which often involves temperatures of 180-200°C acting on the hollow profile section for a period of at least one hour, can be carried out without compromising the seal. Furthermore, it is ensured, especially during these post-treatments, that no escape of heated corrosion inhibitor, for example, from the interior of the hollow profile section occurs, which could lead to defects and thus to rejects during post-treatment, such as powder coating.

[0016] In particular, it can be particularly preferably provided that the intumescent material consists of an ethylene copolymer-based expanding plastic.

[0017] Such an ethylene copolymer-based expanding plastic has proven particularly suitable as an intumescent material and, when activated by heating, can increase its volume several times over its original volume. Thus, the use of this material, in particular, enables extremely effective, durable, and heat-resistant sealing of this area.

[0018] Furthermore, the intumescent material enables an adhesive connection with the surface of the hollow profile.

[0019] Furthermore, it can be particularly preferably provided that the intumescent material consists of an approximately V-shaped or ring-like or strip-like piece of material which can be inserted or is inserted under pressure into the end of the hollow profile section and is arranged there in a positionally secure manner on the inner shell of the hollow profile section until activation.

[0020] Such a piece of material, which has a roughly V-shaped, ring-like, or strip-like form, can be easily inserted into the interior of the pipe, either manually or using an auxiliary tool, or in a semi- or fully automated process, and remains there due to the material's own relaxation or an oversize. This means that, for example, a strip of material bent into a roughly V-shape rests with its free ends on the inner casing due to its own relaxation and remains there, even if the hollow profile section changes position during further processing.

[0021] In the case of oversized pieces of material, this means that the parts remain in the specified position due to friction.

[0022] Such a piece of material remains in its original shape until activated by heating, and after activation by heating, it effectively seals off the area in which the piece of material expands to many times its original volume from the environment.

[0023] However, the inserted piece of material can also be designed in such a way that the wetting of the inner surface with corrosion protection agent can be carried out even after the piece has been inserted by means of a retractable lance.

[0024] Alternatively, it may be particularly preferred that the intumescent material has a granular, granulate-like shape.

[0025] Such an intumescent material with a granular, granular shape can be used particularly in stabilizers that have only one flattened end. In such stabilizers, the end of the stabilizer opposite the flattened end is closed and has, for example, a groove in this area by means of which torsional forces can be transmitted to the stabilizer. When using such a stabilizer, the intumescent material can be inserted first and left there by pivoting into a position with the sealed end facing the ground. In this case, the intumescent material falls towards this end due to a corresponding movement or the acceleration due to gravity. The opposite end is then flattened and, if necessary, provided with a perforation, and the stabilizer is then moved into a position in which the flattened end faces the ground.Due to gravity, the intumescent material now slides in granular or granular form into an area adjacent to the flattened end. After activation in this area, i.e., by heating to a temperature that causes the intumescent material to expand, this area is also effectively sealed by the expanding intumescent material, effectively preventing the penetration of ambient air or liquids, or the leakage of, for example, corrosion inhibitors from the interior of the hollow profile section through the flattened end.

[0026] Due to the inherent adhesion of an intumescent material in pasty form, it can be applied quickly and easily to almost any location within the hollow profile section, for example by inserting it using a lance with a corresponding nozzle, and can remain there until activated.

[0027] According to this process, a corresponding hollow profile section is first bent into its final shape and, if necessary, hardened. The intumescent material is then introduced into one end of the hollow profile section, which is adjacent to the end to be flattened. The distance to this end to be flattened is specified to ensure a complete seal after heating and activation of the intumescent material. The end is then flattened and perforated. If sufficient heat for activation is not already provided by this machining process, the end area is heated so that the introduced intumescent material is activated and expands its volume to several times its original volume.

[0028] If necessary, a corrosion inhibitor can be applied to the inner surface of the hollow profile section before the intumescent material is applied in order to increase its service life.

[0029] If necessary, after flattening and piercing the flattened end, the outer surface of the hollow profile section can be treated, for example, by surface hardening blasting or coating. Coating is usually achieved by powder coating the entire outer surface.

[0030] An embodiment of the invention is illustrated in the figures and described in more detail below.

[0031] It shows: Fig. 1 shows a stabilizer according to the invention with two flattened end regions in side view; Fig. 2 one end of the stabilizer with annular intumescent material before flattening and activation; Fig. 3 likewise with strip-shaped intumescent material piece; Fig. 4 likewise with granular intumescent material; Fig. 5 likewise with a strip-like piece of material bent into a V-shape; Fig. 6 a flattened and perforated end of a stabilizer with activated intumescent material.

[0032] The figures show at least a partial view of a stabilizer 1. Such a stabilizer 1 is suitable for use on motor vehicles. The stabilizer 1 has a hollow profile section 2 made of metal, wherein the hollow profile section 2 made of metal is provided with Fig. 1 both end areas are flattened and sealed internally against the flattened end 3.

[0033] According to the invention, as is particularly evident from Fig. 6, the seal opposite the flattened end 3 within the hollow profile section 2 in a position close to the flattened end 3 or, as in Fig. 6, in an area 4 directly adjacent to the flattened end 3. For sealing, an intumescent material 5 is used in this area 4, as shown in particular in the Fig. 2 to 5, is introduced into the hollow profile section 2. This intumescent material 5 expands after its activation by heating and completely seals this area 4 of the hollow profile section 2 against the flattened end 3. This is particularly evident from Fig. 6. In the Fig. In the examples shown in Figures 2 to 5, the intumescent material 5 has already been introduced into the region 4, but has not yet been activated by heating.

[0034] In the exemplary embodiments, the intumescent material 5 consists of an ethylene copolymer-based expanding plastic. This plastic, in addition to providing complete sealing after activation by heating, has the further advantage of also being able to coat the inner shell of the hollow profile section 2 made of metal with a corrosion protection agent without any leakage occurring in this area after activation of the intumescent material 5. By activating the intumescent material 5 by heating, as particularly in Fig. 6, the area adjacent to the flattened end 3 is completely sealed so that no ambient air or liquids can escape from the interior of the hollow profile section 2 through the flattened end 3 to the outside or can enter the interior of the hollow profile section 2. This enables, in particular, post-processing, for example by means of spraying or dipping processes within an oven, in which temperatures of 180 to 200°C usually prevail, even for a period of at least one hour, without corresponding entry or exit, which would lead to defects and rejects.

[0035] As is particularly evident from Fig. 2, the intumescent material 5 can consist of a piece of material formed into a ring 7, which is inserted into the hollow profile section 2 under slight pressure up to the desired position and remains there in contact with the inner surface due to the material's own relaxation of the ring 7.

[0036] Alternatively, as in Fig. 3, the intumescent material 5 may also consist of a strip-shaped piece of material 8, which is inserted into the hollow profile section 2 under slight pressure and remains there. Again alternatively and in Fig. As shown in Figure 5, the intumescent material 5 can also consist of a strip-like piece of material bent into an approximately V-shape 6. This is also inserted into the end of the hollow profile section 2 under slight pressure and remains there securely until activated by heating. Particularly for the use of stabilizers that can be flattened on one side only, as shown in Fig. 4, the intumescent material 5 may also have a granular, granulate-like shape 9.

[0037] In addition, as is not apparent from the figures, the intumescent material 5 can also be introduced into the hollow profile section interior 2 in pasty form.

[0038] The illustrated material pieces 6, 7, 8 can also be used if the cross-section of the hollow profile section deviates from a circular one, so that hollow profile sections of almost any cross-section can also be effectively sealed by means of the intumescent material 5.

[0039] One in the Fig.1, a stabilizer 1 shown in its entirety, flattened at both ends, can be manufactured, for example, in the following steps. First, the hollow profile section 2 is bent and hardened into its final shape. Subsequently, the intumescent material 5 is introduced into the not yet flattened ends of the hollow profile section 2 and securely positioned there at a predetermined distance from these ends. Subsequently, each end is heated, formed, and perforated. If sufficient heat was not generated during end processing to activate the intumescent material and thus expand the material 5, it is heated to at least the activation temperature of the intumescent material 5, so that the intumescent material 5 expands and effectively seals this area.

[0040] If necessary, a corrosion inhibitor is applied to the inner surface of the hollow profile section 2 before the intumescent material 5 is applied to protect the stabilizer 1. If necessary, after the end machining and punching of the flattened end 3, the surface is then blasted and coated on the outside. A powder coating, including a corresponding pretreatment, is often applied to the outer surface of the hollow profile section 2 as surface protection. List of reference symbols: 1 stabilizer 2 hollow profile section 3 flattened end 4 sealed area 5 intumescent material 6 V-shaped piece of material 7 ring-like piece of material 8 strip-like piece of material 9 granular, granular form

Claims

[1] Method for producing a sealed stabilizer (1) having a hollow profile section (2), comprising at least the following steps: -Bending and hardening a hollow profile section (2) into its final shape -Introducing an intumescent material (5) into the end(s) at a predetermined distance from this end(s) -Flattening and punching the flattened end -Heating the end region with introduced intumescent material (5) to at least the activation temperature of the intumescent material (5). [2] Method according to claim 1, characterized by that a corrosion protection agent is applied to the inner surface of the hollow profile section (2) before or after the introduction of the intumescent material (5). [3] Method according to claim 1 or 2, characterized bythat after flattening and punching the flattened end (3), the surface is irradiated or coated to increase the service life and for protection. [4] Method according to claim 3, characterized by that a powder coating is applied to the outer surface of the hollow profile section (2) as surface protection. [5] Method according to one of claims 1 to 4, characterized by that an ethylene copolymer-based expanding plastic is introduced into the hollow profile section 2 as intumescent material (5). [6] Method according to one of claims 1 to 5, characterized by that the intumescent material (5) consists of a V-shaped (6) or ring-like (7) or strip-like (8) piece of material which is introduced under pressure into the end of the hollow profile section (2) and is arranged there in a positionally secure manner on the inner shell of the hollow profile section (2) until activation. [7] Method according to one of claims 1 to 6, characterized by that intumescent material (5) with a granular, granulate-like shape (9) is introduced into the hollow profile section (2). [8] Method according to one of claims 1 to 6, characterized by that intumescent material (5) with a pasty form is introduced into the hollow profile section (2).

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