A structural element system with damping elements disposed within it

Abstract

The present invention relates to a structural element system for a motor vehicle with a damping element arranged in a structural element, the structural element comprising in one part two joined walls forming a cavity with at least two open ends, the first wall having an opening in this part, and a damping element comprising a support and an expandable material arranged on the support, the support comprising a closing surface and at least one side wall fastened to said closing surface by a rib, the damping element being arranged in the structural element such that the closing surface of the support covers the opening in the first wall and the side wall substantially partially closes the open end of the cavity.

Description

[Technical field]

[0001] The present invention relates to a system of structural elements of a motor vehicle, the system having an insulating element arranged in the structural element. [Background technology]

[0002] In many cases, components, such as bodies and / or frames of transport and mobility means, especially of water or land vehicles or of aircraft, have structures with cavities to allow for a lightweight design. However, these cavities cause a wide variety of problems. Depending on the type of cavity, the cavity must be sealed to prevent the ingress of moisture and dirt, which can cause corrosion of the component. It is often desirable to substantially strengthen the cavity and thus the component, but also to maintain a low weight. It is often also necessary to stabilize the cavity and thus the component, in order to reduce noise that can normally be transmitted along or through the cavity. Many of these cavities have irregular shapes or narrow extents, which makes them more difficult to properly seal, strengthen and insulate.

[0003] Particularly in automobile manufacturing, but also in aircraft manufacturing and shipbuilding, sealing elements (baffles) are therefore used to seal and / or acoustically insulate cavities or reinforcing elements (reinforcements) are used to strengthen the cavities.

[0004] 1 shows diagrammatically the body of a motor vehicle. The body 10 here comprises various structures with cavities, e.g. pillars 14 and carriers or struts 12. Such structural elements 12, 14 with cavities are usually sealed or reinforced with sealing and / or reinforcing elements 16.

[0005] Such conventional sealing elements 16 typically close a cross section of the respective structural element 12, 14. In recent years, it has become increasingly common for such structural elements 12, 14 to be filled or sealed entirely with foam in order to achieve better acoustic insulation. This trend is increasing due to the increasing use of electric vehicles, since the background noise in such vehicles is different from that in conventional vehicles with internal combustion engines and therefore the demands on the sound insulation of the interior compartment are higher.

[0006] To meet these increased demands for sound insulation in vehicles, two-component polyurethane foams are increasingly being used, with which such parts in structural elements are filled. Said solution is, however, disadvantageous because it requires the production line to be equipped with expensive robots and is more labor- and material-intensive. For example, sealing elements must be used to limit the expansion of these two-component foams. Said solution is further disadvantageous because such two-component polyurethane foams typically contain isocyanates, which are toxic (especially carcinogenic) and therefore their use requires increased occupational safety measures and the use of more materials and equipment. Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide a sealing solution which firstly meets the increasing demands for acoustic insulation and secondly is less labour and / or cost intensive. In particular, such a new sealing solution should be suitable for electric vehicles. [Means for solving the problem]

[0008] The object is achieved firstly by a system of a structural element of a motor vehicle, comprising an insulating element arranged in the structural element, the system comprising a structural element comprising at least two joined walls forming in a part a cavity having at least two open ends, the first wall having at least one opening in said part, and an insulating element comprising a carrier and an expandable material arranged on the carrier, the carrier comprising a closing surface and at least one side wall fastened to said closing surface via a rib, the expandable material having an expansion rate of at least 800%, the insulating element being arranged in the structural element such that the closing surface of the carrier overlaps and covers the opening of the first wall when seen in a plan view of the opening, and the at least one side wall is arranged substantially in the plane of the cross-section in the area of ​​the open ends of the cavity, thus closing the cross-section of the cavity in the area of ​​the open ends over at least 50% of said cross-section.

[0009] Said solution has the advantage that numerous functions can therefore be performed by a single component. Firstly, said component allows a large part of the structural element to be filled with foam, whereby very high acoustic insulation performances can be achieved. Secondly, such a component can ensure that the interior of the part is filled with foam in a targeted manner. In particular, by means of a closing surface that is provided as part of the carrier, certain areas of the cavity can be shielded and kept free of expanded material. When using two-component foams, this is not possible or is only possible with great difficulty. In that case, it is particularly necessary that additional elements are used to shield individual areas, for example openings in the wall of the structural element, and are removed again after the foaming operation. This therefore requires increased use of material and increased work effort.

[0010] A further advantage of the solution proposed here is that it makes it possible to achieve similar and / or better acoustic insulation as when using two-component polyurethane foams, but the use of baffles means that the insulation system is nevertheless much easier to handle and apply. These proposed insulation elements can be fitted to the structural elements even before the body is dip-coated, said insulation elements having been expanded in a baking oven after the painting process. In the case of two-component polyurethane foams, both the application process and the equipment requirements are much more complex and expensive.

[0011] Two-component foams also have the disadvantage that the space to be filled with the foam must be delimited using suitable barriers, which in turn requires increased assembly and labor.

[0012] The solution proposed here offers the advantage that particularly good acoustic insulation performances can be achieved, especially for airborne sound waves at frequencies in the range of 500-3000 Hz. As this frequency range is particularly commonly encountered in electric vehicles, the solution proposed here is particularly suitable for use in vehicles with alternative drive systems.

[0013] In the context of this invention, the terms "insulating element" or "insulating" or "insulated" include elements or structures or method steps for dividing and / or closing and / or insulating structural elements. These various features of such insulating elements may occur individually or in combination with each other.

[0014] In one exemplary embodiment, the system is in a motor vehicle having an electric drive, in particular a vehicle without an internal combustion engine.

[0015] In an exemplary embodiment, when viewed in plan view of the opening, the closing surface covers an area that is at least 300% of the area of ​​the opening. In a preferred refinement, the area of ​​the closing surface is at least 400% or at least 600% or at least 800% of the area of ​​the opening.

[0016] Such an embodiment of the closing surface of the carrier has the advantage that the area of ​​the opening in the wall of the structural element can thus be kept free of expanded material so that said opening continues to function for its intended assembly purpose, where no further measures need to be taken in addition to the correct positioning of the insulating element.

[0017] In one exemplary embodiment, the closure surface is arched over the opening in the shape of a dome.

[0018] In one exemplary refinement, the edge region of the closing surface is spaced from the first wall by less than 5 mm.

[0019] Such an arched formation of the closure surface has the advantage that clogging of the opening in the wall of the structural element with foam can therefore be reliably prevented by the shield-like cover provided for the opening. Moreover, such an arched shape of the closure surface has the advantage that space required for the intended assembly purpose remains unused. For example, clips that are often inserted into such openings have a certain structural height that requires such free space.

[0020] In an exemplary embodiment, at least one side wall closes the cross section in the region of the open end of the cavity over in each case at least 60% or at least 70% or at least 80% of said cross section.

[0021] Such a degree of closure of the cross section of the open end of the cavity has the advantage, firstly, that the expansion of the expandable material can be reliably stopped at the intended location, while, secondly, a sufficient open cross section is provided to ensure circulation of the coating liquid.

[0022] In one exemplary embodiment, the carrier has two side walls spaced apart from each other by at least 100 mm. In one exemplary refinement, the two side walls are spaced apart from each other by at least 120 mm or 150 mm.

[0023] Such an embodiment of the carrier has the advantage that a larger portion of the structural element can be filled with foam or insulated than is possible when using conventional insulating elements.

[0024] In one exemplary embodiment, the carrier has two side walls arranged at an angle of 30° to 150° relative to each other. In one exemplary refinement, the two side walls are arranged at an angle of 60° to 120° relative to each other.

[0025] Such an arrangement of the side walls has the advantage that parts of the structural element which are not elongated, but are arcuate or T-shaped, can therefore also be effectively insulated.

[0026] In one exemplary embodiment, the carrier has at least two side walls, with the closing surface of the carrier being disposed substantially between the side walls.

[0027] In one exemplary embodiment, the distance between in each case one side wall and the closing surface is at least 20 mm, so that as a result of the expansion of the expandable material a layer of expanded material having a thickness of at least 20 mm can be formed on a particular side wall.

[0028] In one exemplary refinement, the spacing is at least 30 mm, or at least 40 mm, or at least 50 mm.

[0029] Such a spacing between the side walls of the carrier and the closing surface has the advantage that a correspondingly thick layer of expanded material can thus be formed on the side walls, so that high acoustic insulation performance can be achieved. In tests, it has been found that in particular the combination of the side walls of the carrier with a thick layer of expanded material achieves a particularly good acoustic insulation effect.

[0030] In one exemplary embodiment, the expandable material has an expansion rate of at least 2000%, preferably at least 2500%, and particularly preferably at least 3000%.

[0031] Providing an expandable material with a particularly high expansion rate has the advantage that lighter insulating elements can be used, an aspect that is particularly important in the case of the solution proposed here, since large volumes are intended to be filled with the expandable foam material.

[0032] In one exemplary embodiment, in the region of the opening, the expandable material is not arranged on the side of the closure surface facing towards the opening.

[0033] Such an arrangement has the advantage that openings in the walls of the structural element can thus be kept free of expanded material.

[0034] In one exemplary embodiment, more expandable material is disposed on the side of the carrier facing away from the opening than on the side of the carrier facing toward the opening.

[0035] This has the advantage that portions can be filled with foam in a targeted manner, while certain areas of the cavity are shielded from being filled with foam.

[0036] In one exemplary embodiment, the expandable material is positioned and dimensioned such that the area between the closure surface and the second wall is completely filled with the expanded material after the expansion process.

[0037] This has the advantage that the acoustic insulation performance can therefore be increased even further.

[0038] In one exemplary embodiment, each side wall is connected to the closure surface by 2-6 ribs.

[0039] Providing a small number of ribs between the side wall and the closure surface has the advantage that these areas can therefore be filled as completely as possible with foam and the weight of the carrier can further be kept as low as possible.

[0040] In one exemplary embodiment, the portion of the structural element is elongated and defines a cavity having two open ends.

[0041] In one exemplary refinement, the carrier has two side walls which in each case partially close one open end of the cavity.

[0042] In an alternative embodiment, a portion of the structural element is T-shaped and forms a cavity having three open ends.

[0043] In one exemplary refinement, the carrier has three side walls which in each case partially close one open end of the cavity.

[0044] In one exemplary embodiment, the carrier further includes a fastening element for temporarily fastening the insulating element to the structural element.

[0045] In one exemplary embodiment, the insulating element has two such fastening elements.

[0046] In one exemplary refinement, the fastening element or elements are in the form of a clip or a push pin.

[0047] In alternative embodiments, the fastening element or elements are in the form of welding lugs or hooks or adhesive strips or magnetic elements.

[0048] The expandable material used can in principle be any material that can be foamed. Typically, expandable materials are made to expand thermally, by moisture or by electromagnetic radiation.

[0049] Such expandable materials typically have a chemical or physical blowing agent. Chemical blowing agents are organic or inorganic compounds that decompose under the influence of temperature, moisture or electromagnetic radiation, at least one of the decomposition products being a gas. The physical blowing agents used may be, for example, compounds that are converted to a gaseous state at elevated temperature. Both chemical and physical blowing agents are thus capable of creating foam structures in polymers.

[0050] The expandable material is preferably thermally foamed, and a chemical foaming agent is used. Examples of suitable chemical foaming agents are azodicarbonamide, sulfohydrazide, bicarbonate or carbonate. Suitable foaming agents are also commercially available, for example under the trade name Expancel® from Akzo Nobel, The Netherlands, or under the trade name Celogen® from Chemtura Corp., USA. The heat required for foaming can be introduced by an external or internal heat source, for example an exothermic chemical reaction. The foamable material is preferably foamable at temperatures below 250°C, in particular between 100°C and 250°C, preferably between 120°C and 240°C, preferably between 130°C and 230°C.

[0051] Suitable expandable materials are, for example, one-component epoxy resin systems that do not flow at room temperature, have particularly high impact strength and contain a thixotropic agent, such as aerosil or nanoclay. For example, an epoxy resin system of this type contains 20-50 wt% liquid epoxy resin, 0-30 wt% solid epoxy resin, 5-30 wt% impact modifier, 1-5 wt% physical or chemical blowing agent, 10-40 wt% filler, 1-10 wt% thixotropic agent and 2-10 wt% thermally activatable hardener. Suitable impact modifiers are highly reactive liquid rubbers based on derivatives of nitrile rubber or polyether polyol polyurethanes, core-shell polymers and similar systems known to those skilled in the art.

[0052] Likewise suitable expandable materials are one-component polyurethane compositions based on crystalline polyesters containing blowing agents and having OH groups and mixed with further polyols, preferably polyether polyols, and polyisocyanates with blocked isocyanate groups. The melting point of the crystalline polyesters must be above 50°C. The isocyanate groups of the polyisocyanates can be blocked, for example, with nucleophiles, such as caprolactam, phenol or benzoxalone. Also suitable are blocked polyisocyanates, for example used in powder coating technology, commercially available, for example, under the trade names Vestagon® BF1350 and Vestagon® BF1540 from Degussa GmbH, Germany. So-called encapsulated or surface-inert polyisocyanates, known to those skilled in the art and described, for example, in EP 0204970, are also suitable isocyanates.

[0053] Also suitable as expandable materials are two-component epoxy / polyurethane compositions containing a blowing agent, as described, for example, in WO 2005 / 080524 A1.

[0054] Also suitable as an expandable material is an ethylene-vinyl acetate composition that includes a blowing agent.

[0055] Similarly suitable expandable materials are sold by Sika Corp., USA, for example under the trade names SikaBaffle® 240, SikaBaffle® 250 or SikaBaffle® 255, and described in U.S. Patent Nos. 5,266,133 and 5,373,027. Such expandable materials are particularly preferred for the present invention.

[0056] In one exemplary embodiment, the expandable material is in the form of a heat-induced material.

[0057] This has the advantage that the oven for baking the dip-coated liquid can be used to expand the expandable material and thus to insulate the cavity, as a result of which no additional work steps are required.

[0058] The carrier can be made of any desired material. Preferred materials are plastics, in particular polyurethanes, polyamides, polyesters and polyolefins, preferably high-temperature resistant polymers such as poly(phenylene ether), polysulfones or polyethersulfones, or any desired combination of these materials. Polyamides, in particular polyamide 6, polyamide 6,6, polyamide 11, polyamide 12, or mixtures thereof, are particularly preferably used.

[0059] In one exemplary embodiment, the carrier and the expandable material are manufactured in a two-component injection molding process.

[0060] In alternative embodiments, the carrier and the expandable material are not manufactured in a common process, for example, the carrier may be manufactured in an injection molding process or in a three-dimensional printing process, and the expandable material may be extruded into the carrier in a subsequent manufacturing step.

[0061] In a further alternative embodiment, the insulating element includes a carrier and an expansion element disposed thereon, where the expansion element includes an expandable material. Further, the expansion element may include its own carrier and a coupling element for connecting to the carrier of the insulating element.

[0062] The provision of such expansion elements has the advantage that standardized expansion elements can thus be used which, depending on the requirements, can be used with different carriers to form different insulating elements, for example in one case a carrier having a first shape may be combined with two expansion elements to form one insulating element, and in a second case a carrier having a second shape may be combined with four expansion elements to form different insulating elements.

[0063] Details and advantages of the invention are explained below by means of exemplary embodiments and with reference to schematic drawings. [Brief description of the drawings]

[0064] [Figure 1] 1 shows an exemplary view of a vehicle body. [Figure 2a-2c] 3 shows an exemplary view of a portion of a structural element and a cavity in the structural element. [Figure 3a-3b] 1 shows an exemplary diagram of an insulating element. [Figure 4a-4b] 1 shows an exemplary diagram of an insulating element. [Figure 5a-5c] 1 shows an exemplary diagram of an insulating element. [Figure 6a-6c] 1 shows an exemplary view of a side wall. [Figure 7a-7b] 1 shows an exemplary view of an insulating element in a structural element in a non-expanded state. [Figure 8a-8b] 1 shows an exemplary view of an insulating element in a structural element in an expanded state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] Details of the structural elements 12, 14 are shown in each of Figures 2a-2c. Figure 2a shows two sections 2 of the structural element 12, typically insulated using insulating elements, where one of the sections 2 is elongated and has two open ends 22, and the other of the sections 2 is T-shaped and has three open ends 22.

[0066] In this external view of the structural elements 12, 14, only the second wall 4 is visible, which corresponds to the outer wall of the structural elements 12, 14 in this exemplary embodiment.

[0067] Figure 2b shows the T-section from figure 2a in more detail. In contrast to figure 2a, in figure 2b only the first wall 3 of the structural element 12, 14 is shown. Said first wall 3 has an opening 6.

[0068] Finally, figure 2c is a cross-sectional view of the structural elements 12, 14, showing a cross-section along line AA from figure 2a. The structural elements 12, 14 have a first wall 3 and a second wall 4 joined together and forming a cavity 17.

[0069] A first exemplary embodiment of an insulating element 16 is shown in Figures 3a and 3b. The insulating element 16 comprises a carrier 11 and an expandable material 13 arranged on the carrier 11. The carrier 11 comprises a closing surface 8 and three side walls 9 fastened to said closing surface 8 via ribs 7. The carrier 11 further comprises two fastening elements 5. Figure 3a shows the insulating element 16 from a first side, and Figure 3b shows the same insulating element 16 from a second side.

[0070] Figures 4a and 4b also show, in a schematic way, the same insulating element 16 as in Figures 3a and 3b, where the insulating element 16 is shown in a state before expansion of the expandable material 13 in Figure 4a, and Figure 4b shows the same insulating element after expansion of the expandable material 13, so that the expanded material 13' is visible.

[0071] In this exemplary embodiment, the entire area between the side wall 9 and the closure surface 8 is filled with the expanded material 13', where distance 20 indicates in each case the spacing between one side wall 9 and the closure surface 8. In tests it has been found that a larger distance 20 results in better acoustic insulation performance than a smaller distance 20, when the area between the side wall 9 and the closure surface 8 is substantially filled with the expanded material 13'.

[0072] Figures 5a-5c show alternative embodiments of the insulating element 16, where Figure 5a shows only the carrier 11 and Figure 5b shows only the expansion element 18. As can be seen in Figure 5c, the carrier 11 and the expansion element 18 together form the insulating element 16.

[0073] The carrier 11 again comprises a closure surface 8 , fastening elements 5 and side walls 9 fastened to the closure surface 8 via ribs 7 .

[0074] The expansion element 18 includes an expandable material 13. In this exemplary embodiment, the expansion element 18 further comprises its own carrier and a coupling element 19 for coupling the expansion element 18 to the carrier 11.

[0075] The side wall 9 of the insulating element 16 is shown in more detail, diagrammatically and by way of example, in figures 6a-6c, where figure 6a shows a detail from the insulating element as a whole and figure 6b shows a view of the side wall 9 according to section BB from figure 6a. Figure 6b shows the side wall 9 itself and the rib 7.

[0076] Finally, Fig. 6c shows diagrammatically an exemplary cross section along a plane in the region of the open end of the cavity 17. The structural elements 12, 14 again comprise a first wall 3 and a second wall 4 joined together at a joint. The walls 3, 4 here form the cavity 17. The side wall 9 is now arranged substantially in said plane of the cross section in the region of the open end of the cavity 17, such that the cross section of the cavity 17 is closed by the side wall 9 over more than 50% of its extent. It has been found that such closure of the open end of the cavity 17 by the side wall 9 is sufficient to stop the expansion of the expandable material 13 in the targeted manner.

[0077] Finally, Figures 7a-8b show diagrammatically the system 1 and details from said system 1. In Figures 7a and 7b the expandable material 13 is in a non-expanded state, and in Figures 8a and 8b the expandable material 13 is in an expanded state, such that an expanded material 13' is shown.

[0078] It can be seen in Figures 7b and 8b that the closing surface 8 of the carrier 11 is effective to shield the opening 6 in the wall 3 from the expanded material 13'. The opening 6 therefore remains open for the intended assembly purposes.

[0079] Figure 8b further shows that the area of ​​the cavity 17 between the closing face 8 and the second wall 4 can be completely filled with the expanded material 13. This results in a better acoustic insulation effect. [Explanation of symbols]

[0080] 1 System 2 parts 3 1st wall 4 2nd wall 5 Fastening elements 6 aperture 7. Ribs 8 Closed surface 9 side wall 10. Body 11 Career 12 Structural Elements 13 Expandable materials 13' Expanded material 14 Structural Elements 16 Insulating Elements 17 Cavity 18 Expansion Elements 19 Bonding Elements 20 distance 21 Section 22 Open end

Claims

1. A system (1) for structural elements (12, 14) of a motor vehicle, comprising an insulating element (16) arranged on said structural elements, said system (1) comprising: a structural element (12, 14) comprising at least two joined walls (3, 4) forming a cavity (17) in a portion (2) with at least two open ends (22), the first wall (3) having at least one opening (6) in said portion (2); An insulating element (16) comprising a carrier (11) and an expandable material (13) disposed on the carrier (11), the carrier (11) comprising a closing surface (8) and at least one side wall (9) fastened to the closing surface (8) via a rib (7), the expandable material (13) having an expansion rate of at least 800%; Including, The insulating element (16) is arranged on the structural element (12, 14) so ​​that the closing surface (8) of the carrier (11) overlaps and covers the opening (6) of the first wall (3) when viewed in a plan view of the opening (6), and so that the at least one side wall (9) is arranged substantially in the plane of a cross section (21) in the region of the open end (22) of the cavity (17) thereby closing the cross section of the cavity (17) in the region of the open end (22) over at least 50% of the cross section.

2. 2. A system (1) according to claim 1, wherein, when viewed in plan view of the opening (6), the closing surface (8) covers an area that is at least 300% of the area of ​​the opening (6).

3. 3. A system (1) according to claim 1 or 2, wherein the closing surface (8) is arched in the form of a dome over the opening (6).

4. 3. The system (1) according to claim 1 or 2, wherein the at least one side wall (9) closes the cross section (21) of the cavity (17) in the region of the open end (22) over at least 70% of the cross section.

5. 3. The system (1) according to claim 1 or 2, wherein the carrier (11) has two side walls (9) spaced apart from each other by at least 100 mm.

6. The system (1) according to claim 1 or 2, wherein the carrier (11) has two side walls (9) arranged at an angle of between 30° and 150° relative to each other.

7. 3. The system (1) according to claim 1 or 2, wherein the carrier (11) has at least two side walls (9), and the closing surface (8) of the carrier (11) is arranged substantially between the side walls (9).

8. 3. A system (1) according to claim 1 or 2, wherein the distance (20) between in each case one side wall (9) and the closing surface (8) is at least 20 mm, so that as a result of the expansion of the expandable material (13), a layer of the expanded material (13') having a thickness of at least 20 mm can be formed on the side wall (9).

9. 3. The system (1) according to claim 1 or 2, wherein the expandable material (13) has an expansion rate of at least 2000%.

10. 3. A system (1) according to claim 1 or 2, wherein in the region of the opening (6), no expandable material (13) is arranged on the side of the closing surface (8) facing towards the opening (6).

11. 3. The system (1) of claim 1 or 2, wherein more expandable material (13) is arranged on the side of the carrier (11) facing away from the opening (6) than on the side of the carrier (11) facing towards the opening (6).

12. 3. The system (1) according to claim 1 or 2, wherein the expandable material (13) is positioned and dimensioned such that the area between the closing surface (8) and the second wall (4) is completely filled with expanded material (13') after the expansion process.

13. A system (1) according to claim 1 or 2, wherein each side wall (9) is connected to the closure surface (8) by 2 to 6 ribs (7).

14. 3. A system (1) according to claim 1 or 2, wherein the portion (2) of the structural element (12, 14) is elongated and forms a cavity (17) having two open ends (22), and / or the carrier (11) has two side walls (9), each of which partially closes one open end (22) of the cavity (17).

15. 3. A system (1) according to claim 1 or 2, wherein the portion (2) of the structural element (12, 14) forms a cavity (17) that is T-shaped and has three open ends (22), and / or the carrier (11) has three side walls (9), each of which partially closes one open end (22) of the cavity (17).

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