SYSTEM OF A STRUCTURAL ELEMENT WITH AN INSULATION ELEMENT ARRANGED THEREIN

Description

[0001] The invention relates to a system of a structural element of a motor vehicle with an insulating element arranged in the structural element.

[0002] Many structural components, such as the bodies and / or frames of transport and mobility vehicles, especially watercraft, land vehicles, or aircraft, incorporate cavities to enable lightweight construction. However, these cavities cause a variety of problems. Depending on the type of cavity, it must be sealed to prevent the ingress of moisture and contaminants that can lead to corrosion. Often, it is also desirable to significantly reinforce the cavities and thus the component while maintaining its low weight. Furthermore, it is frequently necessary to stabilize the cavities and therefore the components to reduce noise that would otherwise be transmitted along or through the cavity.Many of these cavities have an irregular shape or a narrow size, making it difficult to properly seal, reinforce, and dampen them.

[0003] Especially in automotive engineering, but also in aircraft and boat construction, sealing elements (English: baffle) are used to seal cavities and / or acoustically insulate them, or reinforcement elements (English: reinforcer) are used to reinforce cavities.

[0004] In Fig. 1 Figure 10 schematically depicts the body of an automobile. The body 10 features various structures with cavities, such as pillars 14 and supports or struts 12. Such structural elements 12, 14 with cavities are typically sealed or reinforced with sealing and / or reinforcing elements 16.

[0005] Conventional sealing elements 16 typically enclose a cross-section of the respective structural elements 12, 14. To achieve better acoustic insulation, entire sections of such structural elements 12, 14 are increasingly being foamed or sealed. This trend is reinforced by the increased use of electric vehicles, because these vehicles have a different noise profile than conventional vehicles with combustion engines, and this places higher demands on the sound insulation of the interior.

[0006] To meet these increased demands regarding vehicle noise insulation, two-component polyurethane foams are increasingly being used to fill such sections in structural elements. However, a disadvantage of this solution is that production lines must be equipped with expensive robots, and increased labor and material input is also required. For example, sealing elements must be used to limit the expansion of these two-component foams. A further disadvantage of this solution is that such two-component polyurethane foams typically contain isocyanates, which are toxic (especially carcinogenic) and therefore require increased occupational safety measures and the use of more materials and equipment. Such systems are described in EP 3 747 739 A1.

[0007] It is therefore an object of the present invention to provide sealing solutions which, on the one hand, meet increased requirements for acoustic insulation and, on the other hand, involve less labor and / or cost. In particular, such a new sealing solution should be suitable for electrically powered motor vehicles.

[0008] This problem is initially solved by a system of a structural element of a motor vehicle with an insulating element arranged in the structural element, the system comprising: a structural element comprising at least two joined walls which form a cavity with at least two open ends on a section, wherein a first wall has at least one opening on this section; an insulating element comprising a support and an expandable material arranged on the support, wherein the support comprises a closed surface and at least one side wall attached to this closed surface via ribs, and wherein the expandable material has an expansion rate of at least 800%;wherein the insulating element is arranged in the structural element such that the closed surface of the support overlaps the opening of the first wall in a top view of the opening, and that the at least one side wall is arranged substantially in a plane of a cross-section in a region of an open end of the cavity and thereby closes the cross-section of the cavity in the region of the open end to at least 50%.

[0009] This solution has the advantage of fulfilling a multitude of functions with a single component. On the one hand, this component allows for the large-volume foam filling of a section of the structural element, resulting in very high acoustic insulation performance. On the other hand, such a component enables targeted foam filling within this section. In particular, by incorporating the closed surface as part of the support structure, certain areas of the cavity can be shielded and kept free of expanded material. This is not possible, or only with great difficulty, when using two-component foams. With two-component foams, additional elements must be used to shield individual areas, such as openings in the walls of the structural element, and these must be removed after the foaming process.This then necessitates an increased use of materials and labor.

[0010] A further advantage of the proposed solution is that it achieves comparable and / or better acoustic insulation than two-component polyurethane foams, but the use of baffles significantly simplifies the handling and application of the insulation system. These proposed insulation elements can be installed in the structural components before the body is dip-coated, and then expanded in a curing oven after painting. With two-component polyurethane foams, both the application and the equipment requirements are considerably more complex and demanding.

[0011] Furthermore, two-component foams have the disadvantage that the areas to be foamed must be separated by suitable blockers. This, in turn, results in higher installation and labor costs.

[0012] The solution proposed here offers the particular advantage of achieving exceptionally good acoustic insulation performance for airborne sound waves in a frequency range between 500 and 3000 Hz. Since this frequency range occurs frequently in electrically powered vehicles, the proposed solution is especially suitable for applications in vehicles with alternative drive systems.

[0013] In the context of this invention, the terms "insulating element," "insulation," and "insulated" encompass elements, structures, and process steps for sealing, closing, and / or insulating a structural element. These various properties of such an insulating element can occur individually or in combination.

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

[0015] In one exemplary embodiment, the closed surface, viewed from above the opening, covers an area that is at least 300% of the opening's area. In a preferred further development, the area of ​​the closed surface is at least 400%, at least 600%, or at least 800% of the opening's area.

[0016] This type of closed surface design of the support has the advantage that it allows an area of ​​the opening in the wall of the structural element to remain free of expanded material, thus ensuring that this opening remains functional for its intended installation purpose. Apart from the correct positioning of the insulation element, no further precautions need to be taken.

[0017] In one exemplary embodiment, the closed surface is domed above the opening.

[0018] In an exemplary training course, an edge area of ​​the closed surface is less than 5 mm away from the first wall.

[0019] Forming such a curvature of the closed surface has the advantage that it reliably prevents foaming of the opening in the wall of the structural element by providing a screen-like covering for the opening.

[0020] Furthermore, such a curvature of the closed surface has the advantage of preserving a space that is necessary for a specific mounting purpose. For example, clips, which are often inserted into such openings, have a certain height that requires this free space.

[0021] In an exemplary embodiment, at least one side wall closes off the cross-section in an area of ​​an open end of the cavity to at least 60% or at least 70% or at least 80%.

[0022] Such a degree of closure of the cross-sections of the open ends of the cavity has the advantage that, on the one hand, the expansion of the expandable material can be reliably stopped at a designated location, while on the other hand, sufficient open cross-section is provided to ensure circulation of coating fluids.

[0023] In one exemplary embodiment, the support has two side walls which are spaced at least 100 mm apart. In a further exemplary embodiment, the two side walls are spaced at least 120 mm or 150 mm apart.

[0024] This design of the support has the advantage that a larger section of the structural element can be foamed or insulated than is the case with conventional insulation elements.

[0025] In one exemplary embodiment, the support has two side walls which are arranged at an angle between 30° and 150° to each other. In a further exemplary embodiment, the two side walls are arranged at an angle between 60° and 120° to each other.

[0026] Such an arrangement of the side walls has the advantage that it also allows sections of structural elements to be effectively insulated, even if they do not have an elongated shape, but rather an arc-shaped or T-shaped form.

[0027] In an exemplary embodiment, the support has at least two side walls, wherein the closed surface of the support is essentially arranged between the side walls.

[0028] In an exemplary embodiment, the distance between each side wall and the closed surface is at least 20 mm, so that an expansion of the expanded material can form a layer of the expanded material at least 20 mm thick on the respective side wall.

[0029] In an example of further training, this distance is at least 30 mm, or at least 40 mm, or at least 50 mm.

[0030] Such gaps between the side wall and the closed surface of the beam have the advantage that they allow a sufficiently thick layer of expanded material to form on the side walls, thus achieving high acoustic insulation performance. Tests have shown that the combination of the beam's side wall with a thick layer of expanded material, in particular, achieves a very high level of acoustic insulation.

[0031] In an exemplary embodiment, the expandable material has an expansion rate of at least 2000%, preferably at least 2500%, and particularly preferably at least 3000%.

[0032] Using an expandable material with particularly high expansion rates has the advantage of allowing the use of lighter insulation elements. Since the proposed solution involves filling a large volume with expandable material, this aspect is of particular importance.

[0033] In an exemplary embodiment, no expandable material is arranged on the side of the closed surface facing the opening in one area of ​​the opening.

[0034] Such an arrangement has the advantage that it allows the opening in the wall of the structural element to be kept free of expanded material.

[0035] In an exemplary embodiment, more expandable material is arranged on a side of the support facing away from the opening than on a side of the support facing the opening.

[0036] This has the advantage that targeted foaming of the section can be achieved, whereby certain areas of the cavity are shielded against foaming.

[0037] In an exemplary embodiment, the expandable material is arranged and dimensioned such that an area between the closed surface and the second wall is completely filled with expanded material after expansion.

[0038] This has the advantage that it can in turn increase acoustic insulation performance.

[0039] In one exemplary embodiment, each side wall is connected to the closed surface by two to six ribs.

[0040] Providing a small number of ribs between the side walls and the closed surface has the advantage that it allows for the most complete possible foaming of these areas, and also keeps the weight of the carrier as low as possible.

[0041] In one exemplary embodiment, the section of the structural element has an elongated shape and forms a cavity with two open ends.

[0042] In an exemplary training course, the carrier has two side walls, each of which partially closes an open end of the cavity.

[0043] In an alternative embodiment, the section of the structural element has a T-shaped form and forms a cavity with three open ends.

[0044] In an exemplary training course, the carrier has three side walls, each of which partially closes an open end of the cavity.

[0045] In an exemplary embodiment, the support also has a fastening element for temporarily fixing the insulation element to the structural element.

[0046] In one exemplary embodiment, the insulating element has two such fastening elements.

[0047] In an exemplary training course, the fastening element or elements are designed as a clip or as a pushpin.

[0048] In an alternative embodiment, the fastening element(s) is designed as a welding tab, a hook, an adhesive strip, or a magnetic element.

[0049] Various materials that can be foamed can be used as expandable materials. Typically, the expandable material is expanded thermally, through moisture, or through electromagnetic radiation.

[0050] Such expandable materials typically contain a chemical or physical blowing agent. Chemical blowing agents are organic or inorganic compounds that decompose under the influence of temperature, humidity, or electromagnetic radiation, with at least one of the decomposition products being a gas. Physical blowing agents can be, for example, compounds that transition to the gaseous state when the temperature is increased. Therefore, both chemical and physical blowing agents are capable of creating foam structures in polymers.

[0051] The expandable material is preferably thermally foamed using chemical blowing agents. Suitable chemical blowing agents include, for example, azodicarbonamides, sulfohydrazides, hydrogen carbonates, or carbonates.

[0052] Suitable propellants are also commercially available, for example, under the trade name Expancel ®< from Akzo Nobel, Netherlands, or under the trade name Celogen ®< from Chemtura Corp., USA.

[0053] The heat required for foaming can be supplied by external or internal heat sources, such as an exothermic chemical reaction. The foamable material is preferably foamable at a temperature of ≤ 250°C, particularly from 100°C to 250°C, more preferably from 120°C to 240°C, and more preferably from 130°C to 230°C.

[0054] Suitable expandable materials include, for example, one-component, non-flowing epoxy resin systems that exhibit particularly high impact strength and contain thixotropic agents such as Aerosile or Nanoclays. Such epoxy resin systems, for example, comprise 20 to 50 wt.% of a liquid epoxy resin, 0 to 30 wt.% of a solid epoxy resin, 5 to 30 wt.% toughness modifiers, 1 to 5 wt.% physical or chemical blowing agents, 10 to 40 wt.% fillers, 1 to 10 wt.% thixotropic agents, and 2 to 10 wt.% heat-activated hardeners. Suitable toughness modifiers include reactive liquid rubbers based on nitrile rubber or derivatives of polyetherpolyol polyurethanes, core-shell polymers, and similar systems known to those skilled in the art.

[0055] Also suitable expandable materials are blowing agent-containing, one-component polyurethane compositions made up of crystalline polyesters containing OH groups in a mixture with other polyols, preferably polyether polyols, and polyisocyanates with blocked isocyanate groups. The melting point of the crystalline polyester should be ≥ 50 °C. The isocyanate groups of the polyisocyanate can be blocked, for example, with nucleophiles such as caprolactam, phenols, or benzoxalones. Furthermore, blocked polyisocyanates such as those used, for example, in powder coating technology and commercially available under the trade names Vestagon® < BF 1350 and Vestagon® < BF 1540 from Degussa GmbH, Germany, are suitable. So-called encapsulated or surface-deactivated polyisocyanates, which are known to those skilled in the art and described, for example, in EP 0 204 970, are also suitable as isocyanates.

[0056] Furthermore, two-component epoxy / polyurethane compositions containing blowing agents, such as those described in WO 2005 / 080524 A1, are suitable as expandable materials.

[0057] Furthermore, ethylene-vinyl acetate compositions containing blowing agents are suitable as expandable materials.

[0058] Suitable expandable materials are also marketed, for example, under the trade names SikaBaffle®< 240, SikaBaffle®< 250 or SikaBaffle®< 255 by Sika Corp., USA, and are described in patents US 5,266,133 and US 5,373,027. Such expandable materials are particularly preferred for the present invention.

[0059] In one exemplary embodiment, the expandable material is designed as a temperature-induced material.

[0060] This has the advantage that the oven can then be used to bake the dip coating fluid, expanding the expandable material and thus insulating the cavity. Therefore, no additional work step is necessary.

[0061] The substrate can be made of any 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 combination of these materials. Polyamide, in particular polyamide 6, polyamide 6.6, polyamide 11, polyamide 12, or a mixture thereof, is particularly preferred.

[0062] In an exemplary embodiment, the carrier and the expandable material are manufactured using a two-component injection molding process.

[0063] In an alternative embodiment, the carrier and the expandable material are not produced in a common process. For example, the carrier can be produced using an injection molding process or a three-dimensional printing process, and the expandable material can be extruded onto the carrier in a subsequent production step.

[0064] In another alternative embodiment, the insulating element comprises a support and an expansion element arranged thereon. The expansion element comprises the expandable material. Furthermore, the expansion element can include its own support and a coupling element for connecting it to the support of the insulating element.

[0065] The provision of such expansion elements has the advantage that standardized expansion elements can be used, which can be combined with different supports to form various insulation elements as needed. For example, in one case a support of one shape can be combined with two expansion elements to form one insulation element, and in another case a support of a second shape can be combined with four expansion elements to form a different insulation element.

[0066] Details and advantages of the invention are described below with reference to exemplary embodiments and schematic drawings. These show: Fig. 1 is an exemplary representation of a body; Figs. 2a to 2c are exemplary representations of a section of a structural element or a cavity of the structural element; Figs. 3a and 3 are exemplary representations of an insulating element; Figs. 4a and 4 are exemplary representations of an insulating element; Figs. 5a to 5c are exemplary representations of an insulating element; Figs. 6a to 6c are exemplary representations of a side wall; Figs. 7a and 7c are exemplary representations of an insulating element in a structural element in an unexpanded state; and Figs. 8a and 8c are exemplary representations of an insulating element in a structural element in an expanded state.

[0067] In the Fig. 2a bis 2c Each section shows a section of a structural element 12, 14. Fig. 2a In structural element 12, 14, two sections 2 are shown, which are typically insulated with insulating elements. One of these sections 2 has an elongated shape and two open ends 22, and the other of these sections 2 has a T-shaped shape and three open ends 22.

[0068] In this external view of the structural element 12, 14, only the second wall 4 is visible, which in this embodiment corresponds to an outer wall of the structural element 12, 14.

[0069] In Fig. 2b is the T-shaped section 2 made of Fig. 2a explained in more detail. In contrast to Fig. 2a is in Fig. 2b Only the first wall 3 of structural element 12, 14 is shown. This first wall 3 has an opening 6.

[0070] In Fig. 2c Finally, a cross-sectional view of structural element 12, 14 is shown, where the cross-section is taken from the Fig. 2a as shown along line AA. The structural element 12, 14 has a first wall 3 and a second wall 4, which are joined together and form the cavity 17.

[0071] In the Fig. 3a und 3b Figure 16 shows a first embodiment of an insulating element 16. The insulating element 16 has a support 11 and expandable material 13 arranged on the support 11. The support 11 comprises a closed surface 8 and three side walls 9 attached to this closed surface 8 by means of ribs 7. The support 11 also includes two fastening elements 5. Fig. 3a The insulation element 16 is shown from a first side, and in Fig. 3b The same insulation element 16 is shown from a second side.

[0072] In the Fig. 4a und 4b is again the same insulating element 16 as in the Fig. 3a und 3b schematically represented. The insulating element 16 is shown in Fig. 4a depicted in a state prior to expansion of the expandable material 13, and in Fig. 4b The same insulating element 16 is shown after an expansion of the expandable material 13, so that the expanded material 13' is visible.

[0073] In this embodiment, the entire area between the side walls 9 and the closed surface 8 is filled with expanded material 13'. The distance 20 denotes the gap between each side wall 9 and the closed surface 8. Tests have shown that larger distances 20 result in better acoustic insulation performance than smaller distances 20, provided that the area between the side walls 9 and the closed surface 8 is substantially filled with expanded material 13'.

[0074] In the Fig. 5a bis 5c An alternative embodiment of an insulating element 16 is shown. In this embodiment, Fig. 5a only carrier 11 is shown, and in Fig. 5b Only one expansion element 18 is shown. Support 11 and expansion element 18 together form the insulating element 16, as shown in the Fig. 5c evident.

[0075] The support 11 in turn comprises a closed surface 8, fastening elements 5 and side walls 9, which are attached to the closed surface 8 via ribs 7.

[0076] The expansion element 18 comprises the expandable material 13. In this embodiment, the expansion element 18 is also equipped with its own support and with a coupling element 19 for coupling the expansion element 18 to the support 11.

[0077] In the Fig. 6a bis 6c A side wall 9 of the insulation element 16 is shown schematically and by way of example. Fig. 6a a section of the entire insulation element, and Fig. 6b shows a view of side wall 9 according to section BB from Fig. 6a In Fig. 6b The side wall 9 itself and the ribs 7 are visible.

[0078] Finally, it shows Fig. 6c A schematic representation of an exemplary cross-section along a plane in the region of an open end of the cavity 17 is shown. The structural element 12, 14 in turn comprises the first wall 3 and the second wall 4, which are joined together at joints. The walls 3, 4 form the cavity 17. The side wall 9 is now arranged essentially in this 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 to more than 50%.

[0079] It has been shown that such a closure of the open end of the cavity 17 by the side wall 9 is sufficient to selectively stop the expansion of the expandable material 13.

[0080] In the Fig. 7a bis 8b Finally, Systems 1, or rather excerpts from these Systems 1, are schematically represented. Within these systems is located... Fig. 7a und 7b the expandable material 13 in its unexpanded state, and in the Fig. 8a und 8b The expandable material 13 is in an expanded state, so that the expanded material 13' is shown.

[0081] In the Fig. 7b und 8b It is evident that the closed surface 8 of the support 11 effectively shields the opening 6 in the wall 3 from the expanded material 13'. Thus, the opening 6 remains free for its intended mounting purpose.

[0082] Furthermore, the Fig. 8b that an area of ​​the cavity 17 between the closed surface 8 and the second wall 4 can be completely filled with expanded material 13. This results in improved acoustic insulation. Bezugszeichenliste

[0083] 1 System 2 Section 3 First wall 4 Second wall 5 Fastening element 6 Opening 7 Rib 8 Closed surface 9 Side wall 10 Body 11 Beam 12 Structural element 13 Expandable material 13' Expanded material 14 Structural element 16 Insulation element 17 Cavity 18 Expansion element 19 Coupling element 20 Space 21 Cross-section 22 Open end

Claims

1. A system (1) of a structural element (12, 14) of a motor vehicle, having an insulating element (16) arranged in the structural element, the system (1) comprising: a structural element (12, 14) which comprises at least two joined walls (3, 4) which, in one portion (2), form a cavity (17) having at least two open ends (22), wherein a first wall (3) has at least one opening (6) in said portion (2); an insulating element (16) comprising a carrier (11) and an expandable material (13) arranged on the carrier (11), wherein the carrier (11) comprises a closed surface (8) and at least one side wall (9) that is fastened to said closed surface (8) via ribs (7), and wherein the expandable material (13) has an expansion rate of at least 800%; wherein the insulating element (16) is arranged in the structural element (12, 14) such that the closed surface (8) of the carrier (11) overlaps and covers the opening (6) of the first wall (3) in a plan view of the opening (6), and such that the at least one side wall (9) is arranged substantially in a plane of a cross section (21) in a region of an open end (22) of the cavity (17) and thus closes the cross section of the cavity (17) in the region of the open end (22) over at least 50% of said cross section.

2. The system (1) as claimed in claim 1, wherein, in a plan view of the opening (6), the closed surface (8) covers an area amounting to at least 300% of an area of the opening (6).

3. The system (1) as claimed in any one of the preceding claims, wherein the closed surface (8) is arched in the shape of a dome over the opening (6).

4. The system (1) as claimed in any one of the preceding claims, 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 said cross section.

5. The system (1) as claimed in any one of the preceding claims, wherein the carrier (11) has two side walls (9) which are spaced from one another by at least 100 mm.

6. The system (1) as claimed in any one of the preceding claims, wherein the carrier (11) has two side walls (9) which are arranged at an angle of between 30° and 150° with respect to one another.

7. The system (1) as claimed in any one of the preceding claims, wherein the carrier (11) has at least two side walls (9), and wherein the closed surface (8) of the carrier (11) is arranged substantially between the side walls (9).

8. The system (1) as claimed in any one of the preceding claims, wherein a distance (20) between in each case one side wall (9) and the closed surface (8) is at least 20 mm, such that, as a result of an expansion of the expandable material (13), a layer of the expanded material (13') with a thickness of at least 20 mm can be formed on the side wall (9).

9. The system (1) as claimed in any one of the preceding claims, wherein the expandable material (13) has an expansion rate of at least 2000%.

10. The system (1) as claimed in any one of the preceding claims, wherein, in a region of the opening (6), no expandable material (13) is arranged on that side of the closed surface (8) which faces toward the opening (6).

11. The system (1) as claimed in any one of the preceding claims, wherein more expandable material (13) is arranged on a side of the carrier (11) facing away from the opening (6) than on a side of the carrier (11) facing toward the opening (6).

12. The system (1) as claimed in any one of the preceding claims, wherein the expandable material (13) is arranged and dimensioned such that a region between the closed surface (8) and the second wall (4) is completely filled with expanded material (13') after an expansion process.

13. The system (1) as claimed in any one of the preceding claims, wherein each side wall (9) is connected to the closed surface (8) by means of two to six ribs (7).

14. The system (1) as claimed in any one of the preceding claims, wherein the portion (2) of the structural element (12, 14) is of elongate shape and forms a cavity (17) having two open ends (22), and / or wherein the carrier (11) has two side walls (9) that partially close in each case one open end (22) of the cavity (17).

15. The system (1) as claimed in any one of claims 1 to 13, wherein the portion (2) of the structural element (12, 14) is T-shaped and forms a cavity (17) having three open ends (22), and / or wherein the carrier (11) has three side walls (9) that partially close in each case one open end (22) of the cavity (17).