Vibration or noise reduction device

Abstract

A vibration or noise reduction device. The device comprises a frame element (101) comprising a plurality of partition elements (102) defining a plurality of slot seats (103); a plurality of resonators (104) inserted into the plurality of slot seats (103), each of the plurality of resonators (102) comprising: a mass portion (105), and at least one connection portion (106) structurally connecting the mass portion (105) to the plurality of partition elements (102) of the frame element (101); a membrane element (107) applied to the frame element (101) and further connecting the mass portion (105) to the plurality of partition elements (102) of the frame element (101), wherein the membrane element (107) completely surrounds the mass portion (105) inside a respective slot seat (103) of the plurality of slot seats (103).

Description

[0001] Title: Vibration or noise reduction device

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention relates to a vibration or noise reduction device.

[0005] In general the present invention is applied in the acoustics field, in particular concerning methods and devices of protection or damping of noise or other acoustic waves in general.

[0006] Prior art

[0007] Document US2020 / 180523A1 relates to a vibration reduction device having an acoustic meta structure mounted on the body of a vehicle and configured to block a noise transmitted by the structure through the body of the vehicle; a plurality of unit structures are arranged at a predetermined interval therebetween, and each of the unit structures includes a frame configured to separate a predetermined space into a predetermined number of separate sections formed by frame walls; and a vibrating element formed at a corner portion of each of the separate sections having a natural frequency to block a vibration transmitted by the body of the vehicle through the frame.

[0008] Document W0201213101 1A3 relates to a vibroacoustic attenuation device comprising: a host structure; at least one mechanical resonator connected to one or more sides of the host structure by means of one or more connection legs; wherein the at least one connected resonator has a vibration mode which is predominantly excitable by the out-of-plane movement of the host structure.

[0009] Document US201 1 / 240402A1 relates to a unit with an acoustic insulation / vibration insulation structure, which comprises: a hollow frame which surrounds an internal space; a film arranged in the internal space, vertically contacting an internal wall of the hollow frame; and a mass arranged on a top surface of the film.

[0010] Document CN103975385B relates to an anti-resonant membrane, comprising a first weight arranged at a central portion of the membrane, and a first hinge structure arranged away from the central portion of the membrane.

[0011] Document FR3056812A1 relates to a structure to block the energy of acoustic waves, the structure comprising a support structure and at least one resonant membrane which covers a cell of the support structure, wherein the at least one resonant membrane comprises at least one weight.

[0012] Document US2018 / 101099A1 relates to an apparatus of protection from acoustic disturbances with a locally resonant material; the apparatus comprises a panel formed by at least one cell comprising: a frame; an elastic membrane whose edge is fixed to the frame; and a mass attached to a position of the membrane at a non-zero distance from the edge.

[0013] However, known devices are not fully effective for the protection or damping of noise or other acoustic waves.

[0014] Summary of the invention

[0015] An object of the present invention is to remedy drawbacks of the prior art.

[0016] A particular object of the present invention is to provide a solution for vibration or noise reduction which is effective.

[0017] A further particular object of the present invention is to provide a device which is effective for the reduction and dissipation of structural vibrations.

[0018] A further particular object of the present invention is to provide a device which is effective for the reduction and dissipation of noise induced by structural vibrations.

[0019] A further particular object of the present invention is to provide a device which can be effectively applied to surfaces of apparatuses or systems in which there are vibrations or noise propagates.

[0020] These and other objects are achieved by a vibration or noise reduction device according to the features of the attached claims which form an integral part of the present description.

[0021] An idea underlying the present invention is to provide a vibration or noise reduction device. The device comprises a frame element comprising a plurality of partition elements defining a plurality of slot seats. The device comprises a plurality of resonators inserted into the plurality of slot seats. Each resonator of the plurality of resonators comprises a mass portion, and at least one connection portion structurally connecting the mass portion to the plurality of partition elements of the frame element. The device comprises a membrane element applied to the frame element and further connecting the mass portion to the plurality of partition elements of the frame element, and the membrane element completely surrounds the mass portion inside a respective slot seat of the plurality of slot seats.

[0022] Advantageously, the device of the present invention allows to have resonators tuned to the target frequency of interest.

[0023] Advantageously, said resonators damp vibration modes of the structure on which the device or multiple devices according to the present invention are applied, allowing to dissipate the structural energy propagation inside the vibrating system.

[0024] Advantageously, said resonators are effective in attenuating the structural dynamics at low / medium frequency (typically, between 10Hz and 2000Hz). In particular, the resonant frequency of the resonators determines the attenuation frequency range in the structure. Advantageously, the resonators can be designed to resonate at different frequencies inside each slot seat.

[0025] Advantageously, the resonators have at least one vibration mode at the target frequency, in which the mass portions resonate with a component with an opposite phase to the movement of the structure on which the device is applied, to react in a contrary manner to the movement thereof. The main component of the resonator movement develops out of the plane, for flexural vibrations of the structure, while with an additional component of the resonator movement it develops tangent to the plane on which the device is applied, for longitudinal and shear vibrations. The more the movement of the resonators has a component out of the application plane, the more effective the dissipation is for flexural vibrations. The more the component is tangent to the application plane, the more effective the dissipation is for longitudinal and shear vibrations. Therefore, each resonator can advantageously have a plurality of vibration modes, which are effective both for flexural vibrations and for longitudinal and shear vibrations.

[0026] Moreover, advantageously, the membrane element has an attenuation effect in a higher frequency range (typically, between 1000Hz and 4000Hz).

[0027] Advantageously, the viscous dissipation physical effect related to the membrane element is due to the relative movement, between the mass portion and the plurality of partition elements of the frame element, which is in an antiphase and in a tangential direction to the surface defined by the frame element.

[0028] Advantageously, the dissipation depends on the thickness and stiffness of the material of the membrane element. Preferably, a degree of porosity or micro-perforation and / or a geometry of micro-cuts are used to modify the stiffness of the membrane element and modulate the structural viscous dissipation degree. In addition, advantageously, a sheet structure with cuts or perforations of the membrane element, in combination with the empty air cavity under the layer itself, may lead to a thermo-viscous coupled effect of acoustic absorption in the same frequency range.

[0029] Advantageously, the viscous dissipation provided by the device of the present invention can be increased, in specific frequency ranges, through the dynamic coupling between the membrane element and vibration modes of the resonators with a movement which is tangential and counter-resonant to the application surface, and resonant along the movement direction of the membrane element.

[0030] Further features and advantages will be more apparent from the following detailed description of preferred non-limiting embodiments of the present invention, and from the dependent claims which outline preferred and particularly advantageous embodiments of the invention.

[0031] Brief description of the drawings

[0032] The invention is illustrated with reference to the following figures, provided by way of non-limiting examples, in which:

[0033] - Figure 1 illustrates a three-dimensional view of a first embodiment of a vibration or noise reduction device according to the present invention.

[0034] Figure 2 illustrates a top view of the device of Figure 1.

[0035] Figure 3 illustrates a side sectional view of the device of Figure 2.

[0036] Figure 4 shows a picture of a prototype corresponding to the first embodiment of Figure 1.

[0037] Figure 5 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0038] Figure 6 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0039] Figure 7 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0040] Figure 8 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0041] Figure 9 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0042] Figure 10 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0043] Figure 11 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0044] Figure 12 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0045] Figure 13 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0046] Figure 14 illustrates a further exemplary embodiment of a vibration or noise reduction device.

[0047] Figure 15 illustrates a side view of a further exemplary embodiment of a vibration or noise reduction device.

[0048] In the different figures, similar elements will be identified by similar reference numbers. If in a same figure there is a plurality of similar elements, only one or only some of them can be identified by a reference number, for ease of reading; the other elements are intended to be encompassed by analogy.

[0049] Detailed description

[0050] Figure 1 illustrates a three-dimensional view of a first embodiment of a vibration or noise reduction device 10, while Figure 2 illustrates a top view of the device 10.

[0051] The device 10 comprises a frame element 101 which comprises a plurality of partition elements 102 (only some indicated by a respective reference) .

[0052] The partition elements 102 define a plurality of slot seats 103 (only some indicated by a respective reference) .

[0053] The device 10 comprises a plurality of resonators 104 inserted into said plurality of slot seats.

[0054] Each resonator 104 comprises a mass portion 105 and at least one connection portion 106.

[0055] The connection portion 106 structurally connects the mass portion 105 to the plurality of partition elements 102 of the frame element 101.

[0056] Preferably, the at least one connection portion 106 comprises a cantilever element. There may be multiple connection portions, and therefore multiple cantilever elements, as will be examined below.

[0057] The resonance of the device 10 can be modified by adjusting geometries and / or materials, as will be further examined.

[0058] The device 10 comprises a membrane element 107, completely surrounding the mass portion 105 inside a respective slot seat 103 of the plurality of slot seats 103, which is better visible in Figure 2. The membrane element 107 is applied to the frame element 101 and connects the mass portion 105 to the plurality of partition elements 102 of the frame element 102.

[0059] Preferably, the material of the membrane element 107 can be the same as the frame element 101 and the resonator 104 or be a different material. Preferably, the slot seats 103 are arranged in a grid.

[0060] Preferably, two resonators 104 and 104b of said plurality of resonators 104 are in two adjacent slot seats 103 and 103b of the plurality of slot seats and comprise respective connection portions 106 and 106b which are symmetrical with respect to a same partition element 102.

[0061] Preferably, the mass portion 105 occupies at least 50% of a surface extension of the respective slot seat 103 or of the portion of the slot seat 103 affected by the resonator 104.

[0062] In a non-limiting example, the plan extension of the device 10 is comprised between 20mm x 20mm and 300mm x 300mm.

[0063] Figure 3 illustrates a side sectional view of the device 10, along the line II-II indicated in Figure 2.

[0064] Preferably, the frame element 101 defines a thickness of the plurality of partition elements 102, the thickness being configured to allow an oscillatory movement of the plurality of resonators 104 inside the plurality of slot seats 103.

[0065] In particular, the thickness of the partition elements 120 and the conformation of the plurality of slot seats 103 allow an oscillatory movement of the plurality of resonators 104 which comprises a movement which is orthogonal to an application plane of the device 10. Moreover, the thickness of the partition elements 120 and the conformation of the plurality of slot seats 103 allow an oscillatory movement of the plurality of resonators 104 which comprises a movement which is tangential to an application plane of the device 10.

[0066] Preferably, the plurality of resonators 104 is configured for a vibration mode at such a resonant frequency as to provide the vibration or noise reduction. In particular, the vibration or noise reduction is effective in the environment, system or apparatus with which one or more devices 10 are associated. In particular, from the physical point of view, the mechanisms which give to the device according to the present the vibration and noise reduction and dissipation properties are related to the following parameters:

[0067] 1) Geometry of the resonators 104.

[0068] 2) Vibration mode and resonant frequency of the resonators 104, influenced by: a. Geometry and material of the mass portions 105. b. Geometry and material of the connection portion 106. c. Thickness and material of the membrane element 107.

[0069] Preferably, the frame element 101 further comprises an adhesive layer configured to apply the device 10 to a surface. In particular, said adhesive layer (not represented) can affect the bottom surfaces of the frame element 101 as represented in Figure 3.

[0070] Preferably, the membrane element 107 has a first thickness which is lower than a second thickness of a resonator 104 of the plurality of resonators. Preferably, the first thickness of the membrane element 107 is lower than 2 mm.

[0071] Preferably, the frame element 101 comprises the plurality of partition elements 102 which are configured to act as a support serving as a spacer, in order to reduce the risk that external objects contact the resonators 104 during the movement thereof.

[0072] Figure 4 shows a picture of a prototype corresponding to the device 10 already described above.

[0073] In this embodiment of the device 10, the frame element 101 and the resonators 104 are made of a single material. Preferably, said material is generally viscoelastic, plastic preferably polymeric (e.g. polyurethanes) or composite or metallic, in particular fibrous.

[0074] Preferably, the membrane element 107 comprises a sheet structure with cuts and / or perforations. In fact, the presence of a micro-perforation and / or micro-cuts in the membrane element 107 allows to improve the viscoelastic dissipation effect at high frequency, favouring the acoustic absorption effect.

[0075] In this embodiment of the device 10, the membrane element 107 is advantageously made of the same material as the frame element 101 and the resonators 104; in particular, it is a material moulded by injection moulding. In case of injection moulding, the connection portions 106, in particular the cantilever elements, are functional to channel the moulded material up to the mass portions 105; a geometry without undercuts is thereby created, which allows the whole device 10 to be manufactured by moulding, with no need to add complexity to the mould.

[0076] Preferably, it is the same waste material from moulding which is used as a membrane element 107, therefore it is not necessary to remove it during the production process.

[0077] In possible alternatives, the device might be manufactured by additive manufacturing or by machining with material removal.

[0078] Figure 5 illustrates a further exemplary embodiment of a vibration or noise reduction device 21, wherein there are four resonators inserted into a frame element which defines four slot seats.

[0079] Figure 6 illustrates a further exemplary embodiment of a vibration or noise reduction device 22, wherein some resonators are connected by two or three connection portions, each comprising a respective cantilever element, which structurally connect the mass portion to the partition elements of the frame element at multiple points.

[0080] Figure 7 illustrates a further exemplary embodiment of a vibration or noise reduction device 23, wherein two pairs of resonators comprise respective connection portions, each comprising a respective cantilever element, which are symmetrical with respect to a same partition element.

[0081] Figure 8 illustrates a further exemplary embodiment of a vibration or noise reduction device 24, wherein the resonators are connected by two or three connection portions, each comprising a respective cantilever element, which are placed at corners of the slot seats.

[0082] Figure 9 illustrates a further exemplary embodiment of a vibration or noise reduction device 25, wherein there are two resonators with circular mass portions in a respective slot seat. Hence, in general, there may be one or more resonators inside a single slot seat.

[0083] Figure 10 illustrates a further exemplary embodiment of a vibration or noise reduction device 26, wherein there are two resonators with mass portions which are different from each other, in particular a circular one and a square one, in a respective slot seat.

[0084] Figure 11 illustrates a further exemplary embodiment of a vibration or noise reduction device 27, wherein there are two resonators with square mass portions in a respective slot seat.

[0085] Figure 12 illustrates a further exemplary embodiment of a vibration or noise reduction device 28, wherein the membrane element comprises a sheet structure with cuts, and wherein the connection portion comprises a cantilever element which has a curvilinear development, that is non-rectilinear.

[0086] Figure 13 illustrates a further exemplary embodiment of a vibration or noise reduction device 29, wherein the membrane element comprises a sheet structure with perforations, and wherein the connection portion comprises a cantilever element which has a curvilinear development, that is non-rectilinear. Figure 14 illustrates a further exemplary embodiment of a vibration or noise reduction device 30, wherein the frame element includes substantially circular partition elements, and wherein the circular mass portions are inserted into the slot seats and connected by connection portions, in particular cantilever elements, which are curvilinear.

[0087] Figure 15 illustrates a side view of a further exemplary embodiment of a vibration or noise reduction device 31, wherein the structure of the frame element is curved in a longitudinal plane, to apply the device 31 to surfaces, apparatuses or machinery with non-planar geometries.

[0088] Industrial applicability

[0089] Advantageously, the present invention allows to effectively reduce vibrations or noise, through the application of one or more devices.

[0090] Among the applications of the present invention, there is the reduction of vibrations and noise for structure-borne noise, that is noise mainly emitted by structural vibrations.

[0091] The present invention finds a preferred application in the Automotive field, in order to reduce noise such as: road noise, engine noise, rattling noise.

[0092] The present invention finds a preferred application in the Aerospace field, in order to reduce noise such as: engine noise, piping noise, walking noise.

[0093] The present invention finds a preferred application in the Machinery field, in order to reduce noise such as: engine noise, piping noise, rotating noise.

[0094] The present invention finds a preferred application in the Appliances field, in order to reduce noise such as: engine noise, piping noise, rotating noise, rattling noise.

[0095] Considering the here-quoted description, the person skilled in the art will be allowed to devise further modifications and alternatives, in order to meet contingent and specific requirements.

[0096] For example, it is possible to combine, in a single device, different embodiments of resonators indicated here. For example, it is possible to provide any number of slot seats and even a different number of resonators inserted thereinto.

[0097] For example, it is possible to adopt any symmetry or asymmetry in the distribution of the device slot seats.

[0098] Clearly, if there are no technical incompatibilities which are apparent to the person skilled in the art, the configurations of specific elements described with reference to certain embodiments, might be used in other here-described embodiments.

[0099] The here-described embodiments are hence to be considered as illustrative and non-limiting examples of the invention.

Claims

CLAIMS1. A vibration or noise reduction device, said device comprising:■ a frame element (101) comprising a plurality of partition elements (102) defining a plurality of slot seats (103);■ a plurality of resonators (104) inserted into said plurality of slot seats (103), each of said plurality of resonators (102) comprising:- a mass portion (105), and- at least one connection portion (106) structurally connecting said mass portion (105) to said plurality of partition elements (102) of said frame element (101);■ a membrane element (107) applied to said frame element (101) and further connecting said mass portion (105) to said plurality of partition elements (102) of said frame element (101), wherein said membrane element (107) completely surrounds said mass portion (105) inside a respective slot seat (103) of said plurality of slot seats (103).

2. The device according to claim 1, wherein said at least one connection portion (106) comprises a cantilever element.

3. The device according to claim 1 or 2, wherein said membrane element (107) comprises a sheet structure with cuts and / or perforations.

4. The device according to any one of claims 1 to 3, wherein said plurality of slot seats (103) are arranged in a grid.

5. The device according to claim 4, wherein two resonators (104, 104b) of said plurality of resonators (104) inserted into two adjacent slot seats (103, 103b) of said plurality of slot seats (103) comprise respective connection portions (106, 106b) which are symmetrical with respect to a same partition element (102) of said plurality of partition elements(102).

6. The device according to any one of claims 1 to 5, wherein said frame element (101) defines a thickness of said plurality of partition elements (102) configured to allow an oscillatory movement of said plurality of resonators (104) inside said plurality of slot seats (103), said oscillatory movement comprising a movement which is orthogonal to an application plane of said device (10) and further a movement which is tangential to said application plane of said device (10).

7. The device according to any one of claims 1 to 6, wherein said frame element (101) further comprises an adhesive layer configured to apply said device to a surface.

8. The device according to any one of claims 1 to 7, wherein said frame element (101) and said plurality of resonators (104) are made of a single material.

9. The device according to claim 8, wherein said membrane element (107) is further made of said single material, preferably said single material being moulded.

10. The device according to any one of claims 1 to 9, wherein said membrane element (107) has a first thickness which is lower than a second thickness of a resonator (104) of said plurality of resonators (104), preferably said first thickness being lower than 2 mm.

11. The device according to any one of claims 1 to 10, wherein said mass portion (105) occupies at least 50% of a surface extension of a respective portion of a slot seat (103) of said plurality of slot seats (103).

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