Abstract
Multilayer damping material for damping a vibrating surface (10) including: at least one constraining layer (4); at least one dissipating layer (1, 3); at least one kinetic spacer layer (2) including multiple spacer elements (2b), the kinetic spacer layer being arranged between the constraining layer and the vibrating surface, when used for damping the vibrating surface, wherein each spacer element has opposite ends, at least one end of each of the multiple spacer elements is embedded in, bonded to, in contact with or in close proximity to the dissipating layer, such that energy is dissipated within the multilayer damping material, through movement of the at least one end of each of the multiple spacer elements; absorbing material as at least one additional layer (12) or within at least one of the above layers.
Claims
1. Multilayer damping material for damping a vibrating surface (10) comprising: at least one constraining layer (4); at least one dissipating layer (1, 3); at least one kinetic spacer layer (2) comprising multiple spacer elements (2b), the kinetic spacer layer being arranged between the constraining layer and the vibrating surface, when used for damping the vibrating surface, wherein each spacer element has opposite ends, at least one end of each of the multiple spacer elements is embedded in, bonded to, in contact with or in close proximity to the dissipating layer, such that energy is dissipated within the multilayer damping material, through movement of the at least one end of each of the multiple spacer elements absorbing material as at least one additional layer (12) or within at least one of the above layers.
2. Multilayer damping material according to claim 1, wherein the absorbing material or layer (12) comprises at least a portion with a porous material.
3. Multilayer damping material according to claim 1, wherein the absorbing material or layer (12) comprises a foam, a woven or non-woven material, the woven or non-woven material comprising thermoplastic or inorganic fibers or a combination of any of the before mentioned materials.
4. Multilayer damping material according to claim 3, wherein the thermoplastic fibers comprise melt-blown microfibers, crimped bulk fibers and/or fine denier staple fibers.
5. Multilayer damping material according to claim 1, wherein the absorbing material or layer (12) is arranged on top of the constraining layer (4).
6. Multilayer damping material according to claim 1, wherein the absorbing material or layer (12) is arranged such that it at least partially fills spaces between the multiple spacer elements (2b) of the kinetic spacer layer (2).
7. Multilayer damping material according to claim 1, wherein the kinetic spacer layer (2) is arranged such as to separate the constraining layer (4) from the dissipating layer (1, 3), or the dissipating layer (1, 3) is arranged such as to separate the constraining layer (4) from the kinetic spacer layer (2).
8. Multilayer damping material according to claim 1, wherein the kinetic spacer layer (2) comprises a base layer (2a), wherein the kinetic spacer elements (2b) extend out of the base layer.
9. Multilayer damping material according to claim 8, wherein the base layer (2a) comprises a) apertures and/or slits, b) is continuous or discontinuous or c) any combination of a) and b).
10. Multilayer damping material according to claim 1, wherein the dissipating layer (1, 3) is a) continuous or discontinuous, b) discontinuous and located only on the one end of the multiple spacer elements (2b), c) comprises apertures and/or slits or d) any combination of a), b) and c).
11. Multilayer damping material according to claim 1, wherein the constraining layer (4) is a) continuous or discontinuous, b) arranged adjacent to, and in contact with at least one dissipating layer (1, 3), c) continuously or discontinuously in contact with at least one dissipating layer (1, 3), or d) any combination of a), b) and c).
12. Multilayer damping material according to claim 8, wherein the constraining layer (4), the dissipation layer (1, 3) and/or the base layer (2a) of the kinetic spacer layer (2) provide(s) perforations, for example micro perforations.
13. Multilayer damping material according to claim 12, wherein the perforations are arranged such that they connect the space between the spacer elements with the space around the multilayer damping material.
14. Multilayer damping material according to claim 1 in form suitable for use in damping vibrations and/or noise within a) a vehicle, b) an appliance, c) any other machine or system comprising a machine, or d) any combination of a), b) and c).
15. An automobile component comprising a multilayer damping material according to claim 1, wherein the component is a car roof, door panel, front-of-dash, or floor panel.
Description
[0062] The invention will now be described in more detail with reference to the following Figures exemplifying particular embodiments of the invention:
[0063] FIG. 1A is a cross-sectional and schematic view of a multilayer constrained damping material in a not deformed stage;
[0064] FIG. 1B is a cross-sectional and schematic view of a multilayer constrained damping material in a deformed stage;
[0065] FIG. 2 is a cross-sectional and schematic view of a multilayer constrained damping material with a kinetic spacer layer;
[0066] FIG. 3 is a cross-sectional and schematic view of one embodiment of a multilayer damping material according to the invention;
[0067] FIG. 4 is a cross-sectional and schematic view of another embodiment of a multilayer damping material according to the invention;
[0068] FIG. 5 is a cross-sectional and schematic view of another embodiment of a multilayer damping material according to the invention;
[0069] FIG. 6 is a cross-sectional and schematic view of another embodiment of a multilayer damping material according to the invention;
[0070] FIG. 7 is a cross-sectional and schematic view of another embodiment of a multilayer damping material according to the invention;
[0071] FIG. 8 is a cross-sectional and schematic view of another embodiment of a multilayer damping material according to the invention and
[0072] FIG. 9 to FIG. 23 are schematic views of embodiments of stems of the kinetic spacer layer of a multilayer damping material according to the invention.
[0073] Herein below various embodiments of the present invention are described and shown in the drawings wherein like elements are provided with the same reference numbers. Additional teachings of the invention are also described below.
[0074] FIG. 1 is a cross-sectional schematic view of a multilayer constrained damping material according to the prior art with a panel 10 that is the component to be damped or the vibrating surface. The damping material itself comprises a dissipating layer 3 and a constraining layer 4. The dissipating layer 3 may comprise a viscoelastic material and the constraining layer 4 may comprise a material that is not as elastic as the dissipating layer 3. When the constraining layer 4 is attached to the dissipating layer, each deformation in the panel 10 leads not only to stretching and compressing in the dissipating layer but also to shear (see FIG. 1B). Thus, a damping material with an additional constraining layer is more effective as damping materials with only a dissipating layer.
[0075] FIG. 2 is a cross-sectional and schematic view of a multilayer constrained damping material according to the prior art with a kinetic spacer layer 2. The Figure shows again a panel 10, which is the component to be damped or the vibrating surface. The multilayer damping material comprises a first dissipating or adhesive layer 1, a kinetic spacer layer 2, a second dissipating layer 3 and a constraining layer 4. The kinetic spacer layer 2 transports the deformation of the panel 10 into the dissipating layer 3. Because of the lever effect the deformation of the dissipating layer 3 gets increased, thus the stretching, compressing and shear caused in the dissipating layer gets increased as well. Thus, the kinetic spacer layer 2, increases the strain in the dissipating layer 3. One example of a kinetic spacer layer material used in the prior art is PU foam.
[0076] FIG. 3 is a cross-sectional and schematic view of one embodiment of a multilayer damping material according to the invention. FIG. 3 shows again a panel 10, the component to be damped or vibration surface. The multilayer damping material according to the invention comprises in that order a first dissipating layer 1, next to the panel 10, a kinetic spacer layer 2, a second dissipating layer 3, a constraining layer 4, an adhesive layer 11 and an absorbing layer 12. The adhesive layer 11 may comprise a spotted pattern. Instead of an adhesive layer fastening clips would work as well. The absorbing layer 12 may also be fastened to the rest of the construction via laser, ultrasonic or high frequency welding depending on the materials used for the absorbing layer 12 and the constraining layer 4. The kinetic spacer layer 2 comprises a base layer 2a and multiple spacer elements 2b extending from the base layer 2a. The base layer 2a is arranged adjacent to the first dissipating layer 1 whereby the multiple spacer elements 2b are extending into the direction of the second dissipating layer 3 (pins up). Providing a kinetic spacer layer 2 with multiple spacer elements 2b provides the advantage of a) saving weight compared to a spacer layer with a homogeneous kinetic spacer layer and b) providing the possibility of bending the multilayer damping material according to the invention. The additional absorbing layer 12 may for example comprise a non-woven insulation web. Other materials as listed above in the general part of the description may also be used for the absorbing layer 12. The absorbing layer 12 may provide an additional absorption of noise that functions as follows: noise entering the absorbing layer 12 functions as oscillating air particles. When these oscillating air particles move along the fibers within the absorbing layer 12, the energy of the oscillating particles gets dissipated as heat due to the relative motion of the fibers and the air within the absorbing layer 12. The more fibers an air particle encounters the more friction is generated and the more energy is dissipated. The efficiency of dissipation may also depend on other factors such as for example on the fiber size. In general, the finer the fibers or the structure of the acoustic damping material, the better the acoustic absorption.
[0077] FIG. 4 is a cross-sectional and schematic view of another embodiment of the multilayer damping material according to the invention. FIG. 4 shows again a panel 10, the component to be damped. The multilayer damping material according to the invention comprises in that order a first dissipating layer 1 next to the panel 10, a kinetic spacer layer 2, an optional second dissipating layer 3, a constraining layer 4, an adhesive layer 11 and an absorbing layer 12, as in the embodiment shown in FIG. 3. For other options or modifications of the adhesive layer see according passage of the description of FIG. 3. If the second dissipating layer 3 is not used, it can be desirable for the constraining layer 4 and the base layer 2a to be bondable to one another, e.g. by being fused together using applied heat, friction, etc. or otherwise secured relative to one another, e.g. with mechanical fastener(s). The kinetic spacer layer also comprises a base layer 2a and multiple spacer elements 2b extending from the base layer 2a. The difference between the embodiment shown in FIG. 3 and in the embodiment shown in FIG. 4 is the orientation of the multiple spacer elements 2b and the base layer 2a relative to the other layers of the multilayer damping material. In FIG. 3 the spacer elements face the constraining layer and in FIG. 4 they face the vibrating surface. The embodiment of FIG. 4 may be advantageous compared to the embodiment of FIG. 3 in the areas of flexibility and easiness of conforming the construction to shaped surfaces. The base layer 2a is arranged adjacent the second dissipating layer 3, whereby the multiple spacer elements 2b are extending into the direction of the first dissipating layer 1 (pins down). The additional absorbing layer 12 may comprise a non-woven insulation web. It may provide an additional absorption of noise that functions as follows: noise entering the acoustic absorbing layer 12 functions as oscillating air particles. When these oscillating air particles move along the fibers within the acoustic absorbing layer 12, the energy of the oscillating air gets dissipated as heat due to relative motion of the fibers and air within the absorbing layer 12. The more fibers an air particle encounters the more friction is generated and the more energy is dissipated. The finer the fibers or the structure of the acoustic damping material, the better the acoustic absorption. The acoustic absorption may also be influenced by other parameters such as for example the size if the fibers.
[0078] FIG. 5 shows again a panel 10, the component to be damped. In this embodiment the multilayer damping material according to the invention comprises in that order a first dissipating layer 1 next to the panel 10, a kinetic spacer layer 2 with an absorbing material 12, an optional second dissipating layer 3 and a constraining layer 4. Different from the embodiments described above, the acoustic absorbing material 12 is arranged such, that it fills at least partially the spaces between the kinetic spacer elements 2b. The absorbing material 12 is thus placed between and around the kinetic spacer elements 2b. The absorbing material 12 may for example be 3M™ Thinsulate™ Acoustic Insulation AU 3002-2. In addition, the constraining layer 4 as well as the second dissipating layer 3 and the base layer 2a of the kinetic spacer layer 2 are provided with micro-perforated spaces (holes) 13. The micro-perforated spaces (holes) 13 are arranged around the spacer elements 2b such that little Helmholtz-resonators are build using the spaces between the spacer elements 2b. In addition, the Helmholtz-resonators are filled with the material of the absorbing layer 12. The Helmholtz-resonators function as described in the general part of the description. The micro-perforated spaces may receive noise, which will be guided through the construction towards the absorbing layer 12 around the kinetic spacer elements 2b. The absorbing layer 12 may absorb the noise in the same way as described above.
[0079] Thus, the embodiment shown in FIG. 5 provides a construction with excellent damping properties. In addition, the embodiment shown in FIG. 5 shows acoustic absorption properties without adding anything to the dimensions (thickness) to the product. Depending on the material used for the acoustic absorbing material 12, the embodiment shown in FIG. 5 may also provide enhanced thermal insulating properties, e.g. when 3M™ Thinsulate™ Acoustic Insulation AU 3002-2 is used as absorbing material 12.
[0080] FIG. 6 shows again a panel 10, the component to be damped. In this embodiment the multilayer damping material according to the invention comprises in that order a first dissipating layer 1 next to the panel 10, a kinetic spacer layer 2 with an absorbing material 12, an optional second dissipating layer 3 and a constraining layer 4. As in the embodiment described with reference to FIG. 5, the acoustic absorbing material 12 is arranged such, that it fills at least partially the spaces between the kinetic spacer elements 2b. The absorbing material 12 is thus placed between and around the kinetic spacer elements 2b. In addition, the constraining layer 4 as well as the second dissipating layer 3 are provided with micro-perforated spaces (holes) 13. The micro-perforated spaces (holes) 13 are arranged around the spacer elements 2b such that little Helmholtz-resonators are build using the spaces between the spacer elements 2b. In addition, the Helmholtz-resonators are filled with the material of the absorbing material 12. The Helmholtz-resonators function as described in the general part of the description. The micro-perforated spaces may receive noise, which will be guided through the construction towards the absorbing material 12 around the kinetic spacer elements 2b. The absorbing material 12 may absorb the noise in the same way as described above. The construction of FIG. 6 provides the same advantages as the construction described with reference to FIG. 5. The only difference between the two embodiments might be that the construction shown in FIG. 5 is more flexible.
[0081] FIG. 7 shows a cross-sectional and schematic view of another embodiment of the multilayer damping material according to the invention. FIG. 7 shows again a panel 10, the component to be damped. The multilayer damping material according to the invention comprises in that order a first dissipating layer 1 next to the panel 10, a kinetic spacer layer 2, an optional second dissipating layer 3, a constraining layer 4, an adhesive layer 11 and an absorbing layer 12. For modifications of the absorbing layer 11 or alternative solutions see general part of the description. The absorbing layer 12 is thus placed on top of the construction as in the embodiment shown in FIG. 3. In addition, the adhesive layer 11, the constraining layer 4 as well as the second dissipating layer 3 are provided with micro-perforated spaces (holes) 13. The micro-perforated spaces (holes) 13 are arranged such that they end in the spaces between the spacer elements 2b of the kinetic spacer layer 2. It is possible that in the embodiment shown in FIG. 7, the spaces between the kinetic spacer elements 2b are filled with absorbing material as shown in FIG. 5 or 6.
[0082] The embodiment shown in FIG. 7 provides excellent damping properties. In addition, due to the additional acoustic absorbing layer 12 it provides absorbing properties. The absorbing properties are enhanced compared to the embodiment shown in FIG. 3 due to the micro-perforated spaces (holes) 13 that function as Helmholtz-resonators. If noise doesn't get absorbed by the acoustic absorbing layer 12 and travels through the entire absorbing layer 12, it will reach the micro-perforated spaces 13 and will get dissipated therein, which leads to an enhanced absorption effect.
[0083] FIG. 8 shows a further cross-sectional and schematic view of another embodiment of the multilayer damping material according to the invention. FIG. 8 shows again a panel 10, the component to be damped. The multilayer damping material according to the invention comprises in that order a first dissipating layer 1 next to the panel 10, a kinetic spacer layer 2, an optional second dissipating layer 3, a constraining layer 4, an adhesive layer 11 and an absorbing layer 12. For modifications of the absorbing layer 11 or alternative solutions see general part of the description. The absorbing layer 12 is thus placed on top of the construction as in the embodiment shown in FIG. 3. In addition, the adhesive layer 11, the constraining layer 4 as well as the second dissipating layer 3 and the base layer 2a of the kinetic spacer layer 2 are provided with micro-perforated spaces (holes) 13. The micro-perforated spaces (holes) 13 are arranged such that they end in the spaces between the spacer elements 2b of the kinetic spacer layer 2. It is possible that in the embodiment shown in FIG. 8, the spaces between the kinetic spacer elements 2b are filled with absorbing material as shown in FIG. 5 or 6.
[0084] The following FIGS. 9 to 23 are schematic top-views of kinetic spacer layers with multiple kinetic spacer elements being arranged in different ways. In FIG. 9, they are arranged equally spaced apart from each other. In FIG. 10, they are arranged homogeneously or uniform at locations within the kinetic spacer layer. Here they are arranged within groups of five kinetic spacer elements. In FIG. 11, they are arranged in-homogeneously or non-uniformly at locations within the kinetic spacer layer. Here they are arranged randomly. It can be desirable for a kinetic spacer layer 2 of the invention to have kinetic spacer elements 2b arranged in transverse rows that are slanted off of the width direction W by an angle (e.g., of about 20° as shown in FIG. 17).
[0085] FIGS. 12A through 12H show schematic side-views of possible kinetic spacer elements of the kinetic spacer layer 2b. As can be seen from the drawings, a lot of different shapes are possible, such as for example different I-shaped, H-shaped, or x-shaped kinetic spacer elements, as well as other shapes such as, for example, spherical-shaped kinetic spacer elements (not shown), which could be solid or thin walled hollow glass, ceramic or plastic beads. The kinetic spacer elements are shown as one homogenous body, but as already described above it is also possible to make them out of more than one material. All the shown shapes can be varied, like varying the size, dimension, make the outer skins more round etc. They may also be hollow.
[0086] FIGS. 13A thorough 13K show schematic top-views of possible kinetic spacer elements of the kinetic spacer layer 2b. As can be seen from the drawings, a lot of different cross-sectional shapes are possible, like circle, square, hexagon, octagon, triangle, odd-shaped polygon, star-shaped kinetic spacer elements. The kinetic spacer elements may be filled or hollow (e.g., tubular). They may be filled with the same material as the outer sheath forming the spacer element or they may be filled with a different material (e.g., a material that provides additional damping characteristics).
[0087] FIG. 14 is a side-view of an additional kinetic spacer layer according to the invention with I-shaped kinetic spacer layer elements extending from a base layer. As can be seen in FIG. 15, they are equally space apart from each other.
[0088] FIG. 16 is a side-view of an additional kinetic spacer layer according to the invention with cylindrical kinetic spacer elements extending from a base layer. The kinetic spacer elements comprise a round top end. It may be desirable to cap the round top end of each of the spacer elements of this kinetic spacer layer, for the reasons discussed above. As can be seen in FIG. 17, they are equally spaced apart from each other.
[0089] FIG. 18 is a top-view of an additional kinetic spacer layer according to the invention with spacer elements being arranged in rows that are positioned with an angle of 20° relative to the edges of the kinetic spacer layer element.
[0090] FIGS. 19A-19C are views of another embodiment of kinetic spacer elements of the kinetic spacer layer according to the invention, where each of the spacer elements 2b are tilted at an angle of about 45° in groups of three adjacent elements 2b. The three spacer elements 2b of each group are joined together at one of their ends (e.g., by adhesive or heat fusing) to form a tripod shape. These groups of three spacer elements 2b are joined to each other at their other ends.
[0091] FIGS. 20A to 20C are schematic views of another embodiment of kinetic spacer elements of the kinetic spacer layer according to the invention, where each of the spacer elements 2b are tilted at an angle of about 45° in groups of four adjacent elements 2b. The four spacer elements 2b of each group are joined together at one of their ends (e.g., by adhesive or heat fusing) to form a shape similar to the tripod shape of the FIG. 23 embodiment. These groups of four spacer elements 2b are likewise joined to each other at their other ends.
[0092] FIG. 21 is a schematic top view of an embodiment of a kinetic spacer layer with perpendicular spacer elements 2b that are each joined to their adjacent spacer elements 2b by relatively thin connector pins or rods 12. The connector pins 12 are shown located midway along the length of each spacer element 2b, but pins 12 can be located at any desired point along the length of each spacer element 2b.
[0093] FIG. 22 is a schematic top view of an embodiment of a kinetic spacer layer with multiple rows of slanted spacer elements 2b that are each tilted at an angle of about 45° and joined together by connector pins or rods 12. Adjacent rows of the spacer elements 2b are tilted in opposite directions. The connector pins 12 are shown located midway along the length of each spacer element 2b, but pins 12 can be located at any desired point along the length of each spacer element 2b.
[0094] FIG. 23 is a schematic top view of an embodiment of a kinetic spacer layer with randomly angled spacer elements 2b that are joined together by connector pins or rods 12. The connector pins 12 are shown located midway along the length of each spacer element 2b, but pins 12 can be located at any desired point along the length of each spacer element 2b.
[0095] All the above described spacer elements and spacer layers may be combined with an absorbing layer according to the invention. All the embodiments described with reference to FIGS. 3 to 8 may comprise any of the shapes disclosed in FIGS. 9 to 23 or any combination of the shapes disclosed in FIGS. 9 to 23.
