Patent Publication Number: US-2021179191-A1

Title: System for insulating a structural element

Description:
The invention relates to a system for insulating a structural element in a motor vehicle. It also relates to a method for insulating a structural element in a motor vehicle. 
     In many cases, components, such as for example bodies and/or frames of transportation and conveyance means, in particular of aquatic or terrestrial vehicles or of aircraft, have structures with cavities in order to make lightweight constructions possible. However, these cavities cause a wide variety of problems. Depending on the nature of the cavity, it has to be sealed in order to prevent the ingress of moisture and dirt, which can lead to corrosion of the components. It is often also desirable to substantially reinforce the cavities, and thus the component, but to retain the low weight. It is often also necessary to stabilize the cavities, and thus the components, in order to reduce noises which would otherwise be transmitted along or through the cavity. Many of these cavities have an irregular shape or a narrow extent, making it more difficult to seal, reinforce and damp them properly. 
     In particular in automotive construction, but also in aircraft construction and boat building, sealing elements (baffles) are therefore used in order to seal and/or acoustically isolate cavities, or reinforcing elements (reinforcers) are used in order to reinforce cavities. 
       FIG. 1  schematically illustrates a body of an automobile. Here, the vehicle body  10  has various structures with cavities, such as for example pillars  14  and carriers or braces  12 . Such structural elements  12 ,  14  with cavities are usually sealed and/or reinforced, respectively, using sealing and/or reinforcing elements  16 . 
       FIGS. 2 a  and 2 b    schematically show a known concept for the sealing and/or reinforcing closure of openings and/or cavities in a motor vehicle. 
     Here,  FIG. 2 a    shows a device  16  prior to an expansion of an adhesive  13 .  FIG. 2 b    shows the same device  16  as a constituent part of the system  1  but after the adhesive  13  has been expanded, that is to say with the expanded adhesive  13 ′. 
     The device  16  is located in a cavity of a vehicle body structure, as is illustrated for example in  FIG. 1 . A portion of such a structural element  12 ,  14  of a vehicle body is schematically illustrated in  FIGS. 2 a  and 2 b   . The device  16  comprises a carrier  11 , which has an edge region  21 . The adhesive  13  is in this case arranged substantially on this edge region  21  of the carrier  11 . 
     A gap exists between the device  16  and the structural element  12 ,  14  prior to the expansion of the adhesive  13 . Said gap makes it possible to coat the structural element  12 ,  14  in order to achieve corrosion protection of the structural element  12 ,  14 . After this coating, the adhesive  13  is usually expanded by the action of heat, the expanded adhesive  13 ′ closing the gap between the device  16  and the structural element  12 ,  14  as a result. Fixing of the device  16 ′ in the structural element  12 ,  14  is moreover also simultaneously achieved as a result of the expansion of the adhesive  13 . A device  16 ′ that is fastened in the structural element  12 ,  14  in this way on the one hand reinforces the structural element  12 ,  14  and on the other hand closes the cavity in the structural element  12 ,  14 . 
     A disadvantage of the previously known sealing and/or reinforcing elements is that the production of these elements is relatively complex, laborious and cost-intensive. 
     Furthermore, the known sealing and/or reinforcing elements have the disadvantage that they have only limited storability. The reason for this in particular is because the adhesive cannot be stored on the elements for any length of time desired or under extreme conditions. 
     It is therefore an object of the present invention to provide an improved system for insulating a structural element in a motor vehicle that avoids the disadvantages of the prior art. In particular, the system should give rise to economic advantages and additionally simplify and/or improve the associated logistics, and in particular the storability. 
     Said object is achieved by a system for insulating a structural element in a motor vehicle, the system comprising: a structural element having a first constituent part and a second constituent part, wherein the constituent parts are joined at a first joining point and at a second joining point, and wherein the structural element forms a cavity; a device having a carrier, wherein the carrier is arranged on the structural element by virtue of a fastening element; and an expandable adhesive, which is arranged on the structural element or on the carrier by pumping or by extruding; wherein the carrier and the expandable adhesive are formed and arranged in such a way that the carrier delimits the expandable adhesive in at least one direction as said adhesive expands. 
     Firstly, this solution has the advantage that, as a result, the device can be produced significantly more simply and cost-effectively in comparison with the prior art. In particular, as per the system proposed here, a device which is in one piece and/or constructed from only one material and/or produced in one step can be used. Consequently, for example, a one-component injection-molding process can be used instead of a two-component injection-molding process. This lowers both the effective costs of the production and an outlay when planning and configuring the device. 
     A core concept of the present invention is that the expandable adhesive is not arranged on the carrier before the device is fastened in the structural element, but rather that the device is fastened in the structural element without adhesive and the expandable adhesive is introduced separately into the system. This has the advantage that the device can be transported and stored much better without the adhesive. This significantly reduces associated logistics costs. In this respect, in a production line of the motor vehicles, the expandable adhesive can be re-administered in each case into the system, for example in the form of bulk product. 
     A further advantage of the system proposed here can be considered that of being able to better reinforce, seal, damp or insulate locations in the cavity of the structural element that are difficult to access by virtue of the separate application of the expandable adhesive than is possible with the systems mentioned in the introduction. In particular, the expandable adhesive can completely fill joining points even before it is activated. 
     Furthermore, the solution proposed here has the advantage that, by means of a (standardized) device, a variety of structural elements can be insulated by using a different amount and/or arrangement of the expandable adhesive in each case. Thus, for example, a first structural element with a larger cavity can be insulated by means of the standard device and a larger amount of expandable adhesive, and a second structural element with a smaller cavity can be insulated by means of the same standard device and a smaller amount of expandable adhesive. Consequently, fewer different devices have to be produced, with the result that the overall costs of the system can be reduced by virtue of greater numbers of items, fewer tools and simpler logistics. 
     In the context of this invention, the designation “insulation” or “insulated” comprises elements or functions or structures or method steps for isolating and/or closing and/or reinforcing and/or damping and/or insulating a structural element. These various properties of such an insulation can in this case arise individually or else in combination with one another. 
     The structural element comprises at least a first constituent part and a second constituent part which are joined together at a first joining point and at a second joining point and thus form a cavity. In this case, the first and the second constituent part of the structural element can be composed in each case of one element or else of a plurality of elements. The structural element can therefore also have more than two joining points. 
     In one exemplary embodiment, the system comprises a plurality of devices having a carrier and a fastening element. By way of example, the system comprises two devices, three devices, four devices, five devices, more than two devices, more than three devices, more than four devices, or more than five devices. 
     In this case, both the shape and the materials of said plurality of devices can in each case be the same or different. 
     In one exemplary embodiment, the carrier is arranged on the first constituent part of the structural element, and the expandable adhesive is arranged on the second constituent part of the structural element. 
     In an alternative embodiment, the carrier is arranged on the first constituent part of the structural element, and the expandable adhesive is likewise arranged on the first constituent part of the structural element. 
     In an alternative refinement, the carrier is arranged on the first constituent part of the structural element, and the expandable adhesive is arranged on the first constituent part and on the second constituent part of the structural element. 
     In a further alternative embodiment, the carrier is arranged on the first constituent part of the structural element, and the expandable adhesive is arranged on the carrier. 
     In one exemplary embodiment, the carrier substantially has an L-shaped or an I-shaped or an H-shaped or a C-shaped or a T-shaped or a W-shaped or a V-shaped or a U-shaped or an N-shaped or a Z-shaped or an O-shaped or a rectangular or an oval or a round or a trapezoidal or a triangular or a polygonal cross section. 
     In one exemplary embodiment, the carrier has a base and a wing. 
     In one exemplary refinement, the fastening element is arranged on the base and the wing delimits the expansion of the expandable adhesive in at least one direction. 
     In one exemplary refinement, the wing forms an angle with the base of between 60° and 160° or of between 70° and 150° or of between 80° and 140°. 
     In one exemplary embodiment, the device or just the carrier is produced by an injection-molding process. 
     In one exemplary refinement, the device or just the carrier is produced by a one-component injection-molding process. 
     In an alternative embodiment, the device or just the carrier is produced by an extrusion process. 
     In one exemplary embodiment, the carrier and the fastening element are formed in one piece. 
     In a further exemplary embodiment, the carrier and the fastening element are formed from the same material. 
     In one exemplary embodiment, the carrier comprises a plastic, in particular polyamide. 
     In one exemplary embodiment, the carrier comprises a fiber-reinforced plastic, in particular a glass fiber-reinforced or carbon fiber-reinforced plastic. 
     In principle, the carrier can consist of a variety of materials. Preferred materials are plastics, in particular polyurethanes, polyamides, polyesters and polyolefins, preferably polymers which can withstand high temperatures such as poly(phenylene ethers), polysulfones or polyether sulfones, which in particular are also foamed; metals, in particular aluminum and steel; or grown organic materials, in particular wood materials or other (densified) fibrous materials, or glass-type or ceramic materials; especially also foamed materials of this type; or any desired combinations of these materials. Polyamide, in particular polyamide 6, polyamide 6.6, polyamide 11, polyamide 12, or a mixture thereof, is particularly preferably used. Combinations with fibers, such as, for example, glass fibers or carbon fibers, are also possible. 
     Furthermore, the carrier can have any desired construction and any desired structure. It may be solid, hollow, or foamed, or have a grid-like structure, for example. Typically, the surface of the carrier may be smooth, rough or structured. 
     In one exemplary embodiment, the device has a substantially circular or oval or elongate or irregularly shaped outline. 
     In one exemplary embodiment, the expandable adhesive has an expansion rate of at least 200% or of at least 300% or of at least 400% or of at least 500% or of at least 800%. 
     Such an expandable and pumpable adhesive is described, by way of example, in European patent application EP 3 281 970 A1. 
     An example of such an expandable, pumpable adhesive is an adhesive that can be obtained under the trade name Sikaseal®. 
     An example of an expandable adhesive which can be extruded can be obtained under the name Sika Baffle® 455. 
     In one exemplary embodiment, the expandable adhesive is arranged on the second constituent part of the structural element in the form of a bead or a plurality of beads. 
     In one exemplary embodiment, the expandable adhesive is arranged on the second constituent part of the structural element by a robot. 
     In one exemplary embodiment, the at least one bead has a diameter of from 2 to 20 mm or of from 4 to 18 mm or of from 6 to 16 mm. 
     In one exemplary embodiment, the at least one bead has a length of at least 10 mm or of at least 20 mm or of at least 30 mm or of at least 50 mm or of at least 100 mm. 
     In one exemplary embodiment, the expandable adhesive is in contact with the structural element at the first joining point and at the second joining point. 
     In one exemplary embodiment, in the region of the first and the second joining point, the expandable adhesive in each case touches both the first constituent part of the structural element and the second constituent part of the structural element. 
     In one exemplary embodiment, the expandable adhesive has, in each case proceeding from the joining points, an extent along the second constituent part of the structural element of at least 10 mm or of at least 15 mm or of at least 20 mm or of at least 30 mm or of at least 40 mm. 
     In one exemplary embodiment, the expandable adhesive forms a continuous element between the first joining point and the second joining point. 
     In one exemplary embodiment, the expandable adhesive forms a single cohesive element. In an alternative embodiment, a plurality of non-cohesive expandable adhesives forms a plurality of non-cohesive elements. 
     In one exemplary embodiment, the expandable adhesive is a pumpable or extrudable material. 
     In one exemplary embodiment, the expandable adhesive is pumpable at a temperature of less than 80° C., preferably of less than 70° C., preferably of less than 60° C., particularly preferably of less than 50° C. 
     In one exemplary embodiment, the expandable adhesive is extrudable at a temperature of less than 100° C., preferably of less than 90° C., preferably of less than 80° C., particularly preferably of less than 70° C. 
     In one exemplary embodiment, the expandable adhesive is pumpable or extrudable at a temperature which is below an activation temperature of the second expandable adhesive by at least 20 K or by at least 30 K or by at least 40 K or by at least 50 K or by at least 60 K. 
     In one exemplary embodiment, the fastening element is in the form of a clip. 
     In an alternative embodiment, the fastening element is in the form of a welding tab or in the form of a magnetic element or in the form of an adhesive or in the form of a hook. 
     In one exemplary embodiment, the structural element has an opening, wherein the carrier is arranged in such a way that the opening is free of expanded adhesive after the expandable adhesive has been expanded. 
     Such an arrangement of the carrier has the advantage that, as a result, openings in the structural element, as are used for example for cable leadthroughs or the like, can be kept free of expanded adhesive such that the function of such openings is not adversely affected. 
     In one exemplary embodiment, a distance between the carrier and the structural element amounts to between 2 and 6 mm or between 3 and 5 mm. 
     The object set in the introduction is additionally achieved by a method for insulating a structural element in a motor vehicle, the method comprising the steps of: providing a device having a carrier; arranging the device on the structural element; arranging an expandable adhesive on the structural element or on the carrier by pumping or by extruding; joining a first constituent part and a second constituent part of the structural element to form the structural element, wherein the device and the expandable adhesive are arranged in a cavity between the constituent parts of the structural element; and expanding the expandable adhesive, wherein the carrier delimits the expansion of the expandable adhesive in at least one direction. 
     In one exemplary embodiment, the expandable adhesive is arranged by pumping at a temperature of less than 80° C. or of less than 70° C. or of less than 60° C. or of less than 50° C. 
     In one exemplary embodiment, the expandable adhesive is arranged by extruding at a temperature of less than 100° C. or of less than 90° C. or of less than 80° C. or of less than 70° C. 
     In one exemplary embodiment, the expandable adhesive is expanded at a temperature of more than 100° C. or of more than 110° C. or of more than 120° C. or of more than 140° C. 
     In one exemplary embodiment, the method is carried out by a system according to the description above. 
     In one exemplary embodiment, the expandable adhesive is arranged on the structural element or the carrier by a robot. 
     In one exemplary embodiment, the expandable adhesive is pumped or extruded onto the second constituent part of the structural element. 
     In one exemplary embodiment, the adhesive is arranged on the structural element or the carrier before or after the arrangement of the device on the first constituent part of the structural element. 
     In one exemplary embodiment, heat is employed during the activation of the expandable adhesive, in particular the adhesive is activated in a finishing oven or in a corrosion-protection oven. 
    
    
     
       Details and advantages of the invention will be described below on the basis of exemplary embodiments and with reference to schematic drawings, in which: 
         FIG. 1  shows an exemplary illustration of a vehicle body according to the prior art; 
         FIGS. 2 a  and 2 b    show schematic illustrations of an exemplary device according to the prior art; 
         FIG. 3  shows a schematic illustration of an exemplary device in a structural element; 
         FIGS. 4 a  and 4 b    show schematic illustrations of exemplary devices; and 
         FIGS. 5 a  to 6 b    show schematic illustrations of exemplary systems for insulating structural elements. 
     
    
    
       FIG. 3  shows, schematically and by way of example, a device  16  in a structural element  12 ,  14  in a cross-sectional illustration. In this exemplary embodiment, the device  16  has a carrier  11  with an L-shaped cross section. In this respect, a first leg forms a base  17  of the carrier, and a second leg forms a wing  18 . The base  17  and the wing  18  form an angle  9  which amounts to approximately 90° in this exemplary embodiment. A fastening element  5  is arranged on the base  17 . The device  16  is arranged on the structural element  12 ,  14  by virtue of this fastening element  5 . In this exemplary embodiment, the fastening element  5  is in the form of a clip. 
     In this exemplary embodiment, a distance  4  between the carrier  11  and the structural element  12 ,  14  amounts to approximately 4 mm. Such a distance  4  makes it possible on the one hand to coat the structural element  12 ,  14  with a finishing liquid prior to an expansion of the expandable adhesive, and allows the carrier  11  on the other hand to effectively delimit an expansion of the expandable adhesive in at least one direction. 
       FIGS. 4 a  and 4 b    depict, schematically and by way of example, two different devices  16  in a three-dimensional illustration. The device  16  in  FIG. 4 a    has a substantially circular outline. In addition, the carrier  11  in this exemplary embodiment in turn has a substantially L-shaped cross section. In this case, the carrier  11  has a base  17  and a wing  18 , which form an angle  9 . In this exemplary embodiment, arranged on the base  17  are three fastening elements  5  for arranging the device  16  on a structural element. 
     The device  16  in  FIG. 4 b    has a rectangular cross section. In this case, the device  16  has an elongate form and/or has an elongate outline. In turn, the carrier  11  of the device  16  has a base  17  and a wing  18 , which form an angle  9 . In this exemplary embodiment, the base  17  and the wing  18  are supplemented by further walls of the carrier  11 . In this exemplary embodiment, arranged on the base  17  of the carrier  11  are two fastening elements  5  for arranging the device  16  in a structural element. 
       FIGS. 5 a  to 6 b    illustrate, schematically and by way of example, systems  1  for insulating a structural element  12 ,  14 . 
       FIGS. 5 a  and 5 b    illustrate a system  1 , wherein the expandable adhesive  13  is arranged on the structural element  12 ,  14 . In this exemplary embodiment, the expandable adhesive  13  is arranged on a first constituent part  12 . 1 ,  14 . 1  of the structural element, and the device  16  is arranged on a second constituent part  12 . 2 ,  14 . 2  of the structural element. The two constituent parts  12 . 1 ,  14 . 1 ,  12 . 2 ,  14 . 2  of the structural element are joined together at a first joining point  6  and at a second joining point  7 . In the process, the structural element  12 ,  14  forms a cavity  3  in which both the expandable adhesive  13  and the device  16  are arranged. 
     The device  16  comprises a carrier  11  and a fastening element  5 . The carrier  11  has a base  17  and a wing  18 , which form an angle  9 . The wing  18  is arranged here in front of an opening  8  in the structural element  12 ,  14 . As a result, the carrier  11  and in particular the wing  18  thereof delimits the expansion of the expandable adhesive  13  in the direction of this opening  8 , and therefore the expandable adhesive  13 ′ cannot pass into the region of the opening  8 . This can be seen in  FIG. 5 b   , in which the system  1 ′ is illustrated after the expandable adhesive  13  has been expanded. 
       FIGS. 6 a  and 6 b    illustrate a further exemplary system  1  for insulating a structural element  12 ,  14 . By contrast to the system  1  in  FIGS. 5 a  and 5 b   , in this exemplary embodiment the expandable adhesive  13  is arranged not on the structural element  12 ,  14 , but rather on the carrier  11 . In this respect, the expandable adhesive  13  is arranged on the carrier  11  by pumping or extruding in the form of a bead. 
     In turn, the carrier  11  delimits an expansion of the expandable adhesive  13  in at least one direction, with the result that a predetermined region of the structural element  12 ,  14  and/or the cavity  3  thereof remains free of expanded adhesive  13 ′ after the expandable adhesive  13  has been expanded. This is illustrated in  FIG. 6   b.    
     LIST OF REFERENCE SIGNS 
     
         
           1  System 
           3  Cavity 
           4  Distance 
           5  Fastening element 
           6  First joining point 
           7  Second joining point 
           8  Opening 
           9  Angle 
           10  Vehicle body 
           11  Carrier 
           12  Structural element 
           12 . 1  First constituent part 
           12 . 2  Second constituent part 
           13  Expandable adhesive 
           14  Structural element 
           14 . 1  First constituent part 
           14 . 2  Second constituent part 
           16  Device 
           17  Base 
           18  Wing 
           21  Edge region