Sound-absorbing pad for automobiles

Abstract

The present invention relates to a sound-absorbing pad for automobiles, having: a PET felt layer (110) made of PET felt to absorb high-frequency noise; and an air-containing layer (120) that is provided with a predetermined thickness on top of the PET felt layer (110) and has air layers (121a) to reduce sound energy and absorb low-frequency noise, wherein the PET felt layer (110) is formed with a thickness in the range of 5 to 10 mm, and the air-containing layer (120) is formed with a thickness in the range of 10 to 30 mm.

Description

Automotive sound-absorbing pads

[0001] The present invention relates to a sound-absorbing pad for automobiles, and more specifically, to a sound-absorbing pad with improved sound absorption performance.

[0002] Sound-absorbing pads used in automobiles are primarily utilized to reduce noise entering the vehicle interior and improve ride comfort. They play a role in enhancing the quietness of the vehicle's interior by absorbing engine noise, road noise, and wind noise.

[0003] Sound-absorbing pads are used in the engine room, dashboard, interior of the doors, floor, and trunk, etc.

[0004] Conventional sound-absorbing pads for automobiles are made of PET felt. PET felt sound-absorbing pads are produced as non-woven fabric by compressing recycled polyester fibers; they are eco-friendly and offer excellent sound absorption performance, making them widely used as sound-absorbing materials for various vehicles.

[0005] However, while PET felt sound-absorbing pads are effective against high-frequency noise, they have limitations in absorbing low-frequency noise.

[0006] In addition, PET felt sound-absorbing pads may deform or experience performance degradation if exposed to moisture or contaminants for a long period. Furthermore, PET sound-absorbing pads may have limited performance if they are thin, and there are limitations in that increasing the thickness increases the weight.

[0007] (Patent Document 1) Published Patent No. 10-2013-0060677 "Method for manufacturing a sound-absorbing pad for automobiles"

[0008] (Patent Document 2) Registered Patent No. 10-2087829 "Sound-absorbing pad for laminating automotive interior materials"

[0009] The objective of the present invention is to solve the aforementioned problems and to provide an automotive sound-absorbing pad that compensates for the disadvantages of PET material sound-absorbing pads and improves sound absorption performance.

[0010] The above-mentioned objectives and various advantages of the present invention will become more apparent to those skilled in the art from the preferred embodiments of the present invention.

[0011] The objective of the present invention can be achieved by a sound-absorbing pad for automobiles. The sound-absorbing pad for automobiles of the present invention comprises a PET felt layer (110) formed of PET felt to absorb high-frequency noise; and an air-forming layer (120) having a certain thickness on the upper portion of the PET felt layer (110) and containing an air layer (121a) to reduce sound energy and absorb low-frequency noise, wherein the PET felt layer (110) is preferably formed in a range of 5 to 10 mm and the air-forming layer (120) is preferably formed in a range of 10 to 30 mm.

[0012] Here, the air forming layer (120) is preferably provided with any one of a honeycomb structure, a double-wall structure, a diagonal grid structure, and a foam air layer combined structure.

[0013] Additionally, it includes a polyurethane coating layer (130) provided on the upper part of the air-forming layer (120) to prevent contamination from external impact, and the polyurethane coating layer (130) is formed on a base layer (131) coupled to the upper part of the air-forming layer (120), and the polyurethane coating layer (130) can be formed in a range of 0.5 to 2 mm.

[0014] Additionally, the device further includes a sound dispersion layer (140) provided on the upper part of the air-forming layer (120) to reflect sound and disperse sound, and a plurality of pyramid-shaped pyramid protrusions (141) may be provided on the plate surface of the sound dispersion layer (140).

[0015] The sound-absorbing pad according to the present invention is formed by bonding a PET felt layer, an air-forming layer, and a polyurethane coating layer in multiple layers. Each layer, provided with different materials and shapes, can effectively remove not only high-frequency noise but also low-frequency noise, thereby improving sound absorption performance.

[0016] In addition, the polyurethane coating layer prevents surface contamination, which has the effect of extending the lifespan of the sound-absorbing pad.

[0017] FIG. 1 is a perspective view illustrating the configuration of a sound-absorbing pad according to a preferred embodiment of the present invention.

[0018] FIG. 2 is an exploded perspective view illustrating the configuration of a sound-absorbing pad according to a preferred embodiment of the present invention.

[0019] FIG. 3 is an illustrative diagram showing various modifications of the air-forming layer of a sound-absorbing pad according to a preferred embodiment of the present invention.

[0020] FIG. 4 is a perspective view illustrating the configuration of a sound-absorbing pad according to another embodiment of the present invention.

[0021] To fully understand the present invention, preferred embodiments of the invention are described with reference to the accompanying drawings. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be interpreted as being limited to the embodiments described in detail below. These embodiments are provided to more completely explain the present invention to those with average knowledge in the art. Accordingly, the shapes of elements in the drawings may be exaggerated to emphasize clearer explanations. It should be noted that in each drawing, identical components may be depicted with the same reference numeral. Detailed descriptions of known functions and configurations that are deemed to unnecessarily obscure the essence of the present invention are omitted.

[0022]

[0023] FIG. 1 is a perspective view illustrating the configuration of a sound-absorbing pad (100) according to a preferred embodiment of the present invention, and FIG. 2 is an exploded perspective view illustrating the configuration of the sound-absorbing pad (100) in disassembly.

[0024] As illustrated in the drawing, a sound-absorbing pad (100) according to a preferred embodiment of the present invention comprises a PET felt layer (110) formed of PET felt, an air-forming layer (120) provided on the upper part of the PET felt layer (110) and having an air layer (121a), and a polyurethane coating layer (130) provided on the upper part of the air-forming layer (120).

[0025] A sound-absorbing pad (100) according to a preferred embodiment of the present invention has a multilayer structure comprising a PET felt layer (110) that absorbs high-frequency noise, an air-forming layer (120) that disperses and blocks low-frequency noise through an air layer (121a), and a polyurethane coating layer (130) that protects the air-forming layer (120) from moisture and contamination. This provides the advantage of compensating for the disadvantages of conventional PET felt sound-absorbing pads and improving sound absorption performance.

[0026]

[0027] The PET felt layer (110) is provided at the bottom of the multilayer sound-absorbing pad (100) and serves as the initial absorption of sound. The PET felt layer (110) has a porous fiber structure that absorbs sound and disperses noise energy. Because the PET felt layer (110) is lightweight and flexible, it allows the sound-absorbing performance to be maintained while reducing the overall weight of the sound-absorbing pad (100).

[0028] The PET felt layer (110) can be made using recycled PET bottles. The PET felt layer (110) uses 1 to 6 denier fine PET fibers. These PET fibers form the thickness and density of the PET felt layer (110) required for noise absorption. The PET fibers are aligned and intertwined using a carding machine to form a layer in the form of a nonwoven fabric. Then, the PET fiber layer can be manufactured by compressing it using heat and pressure and then cutting it into the required shape.

[0029] It is preferable to form the thickness (d1) of the PET felt layer (110) to be 5 to 10 mm. Forming the thickness (d1) of the PET felt layer (110) to be 5 to 10 mm is intended to effectively perform initial sound absorption. This thickness allows for sufficient sound absorption while minimizing weight, making it suitable for use in automobiles where lightweighting is required.

[0030] The PET felt layer (110) is made of porous fibers, so if the thickness is thinner than 5 mm, the sound absorption effect is reduced, and if it is thicker than 10 mm, the weight increases, making it inefficient.

[0031]

[0032] The air-forming layer (120) is provided with a certain thickness on the upper part of the PET felt layer (110) to form an independent air layer (121a) containing air, thereby causing noise to be reflected and dispersed internally. The structure of this air-forming layer (120) significantly improves the low-frequency noise absorption performance of the sound-absorbing pad (100).

[0033] According to a preferred embodiment of the present invention, the air-forming layer (120) is formed as a honeycomb structure (121). The honeycomb structure (121) has the structural advantage of being lightweight while maintaining strength. In addition, the air layer (121a) formed inside each honeycomb structure (121) has the advantage of not only absorbing noise but also providing structural stability.

[0034] The air-forming layer (120) having a honeycomb structure (121) can be formed of lightweight and durable polypropylene.

[0035] The air-forming layer (120) of the honeycomb structure (121) is manufactured by stacking multiple polypropylene sheets with an adhesive, attaching them in an alternating pattern at regular intervals, and expanding the bonded polypropylene sheets. The polypropylene sheets are expanded to form honeycomb-shaped hexagonal cells, and after thermoforming the structure with the formed hexagonal cells, it is manufactured by cutting it to fit the size of the PET felt layer (110).

[0036] Here, the size of the unit hexagon (cell) of the honeycomb structure (121) is 2 to 10 mm, which is effective for absorbing low-frequency noise. Since low-frequency noise has a long wavelength, the cell size of the honeycomb structure (121) must be larger than a certain level to effectively disperse and absorb sound energy. While larger cells absorb low-frequency noise better, if they are too large, structural stability may decrease. Therefore, a cell size of about 5 to 7 mm is desirable for balancing low-frequency absorption and structural strength.

[0037] It is preferable to form the thickness (d2) of the air-forming layer (120) of the honeycomb structure (121) to be 10 to 30 mm. The air-forming layer (120) of the honeycomb structure (121) serves to disperse low-frequency noise that is not properly processed by the PET felt layer (110). If the thickness of the air-forming layer (120) is less than 10 mm, it is suitable for general sound absorption effects and cannot absorb low-frequency noise. On the other hand, if the thickness of the air-forming layer (120) is thicker than 30 mm, it is suitable for blocking low-frequency noise more powerfully than that generated in a car, and there is a limitation that the thickness of the entire sound-absorbing pad (100) is thick, making it difficult to properly place it where needed.

[0038]

[0039] The polyurethane coating layer (130) has excellent resistance to the external environment and protects the air-forming layer (120) located underneath from moisture or contaminants. In addition, the surface is coated to protect the sound-absorbing pad (100) from external impact or wear.

[0040] The lifespan of the sound-absorbing pad (100) can be extended and its durability increased by this polyurethane coating layer (130).

[0041] The polyurethane coating layer (130) is formed by coating polyurethane onto the base layer (131). It is preferable that the base layer (131) be made of a non-woven fabric material that can be smoothly bonded with polypropylene, which is the material of the honeycomb-structured air-forming layer (120).

[0042] The polyurethane coating layer (130) is formed by mixing polyol and isocyanate to create polyurethane, which is then coated onto the surface of the base layer (131) using tools such as a spray, roller, or brush. The coated polyurethane is cured by applying heat. During the curing process, the polyurethane coating layer (130) becomes hard and acquires durability and waterproofing capabilities.

[0043] The thickness (d3) of the polyurethane coating layer (130) is preferably 0.5 to 2 mm. If the thickness (d3) of the polyurethane coating layer (130) exceeds 2 mm, flexibility decreases, and if it is thinner than 0.5 mm, durability may be weakened. A thickness between 0.5 and 2 mm is desirable as it can balance protective performance and flexibility.

[0044]

[0045] Here, the PET felt layer (110) and the air-forming layer (120) formed from a honeycomb structure (121) of polypropylene material can be firmly joined together through ultrasonic welding. The PET felt layer (110) and the air-forming layer (120) are placed in an ultrasonic welding device, and the two layers are joined through high-frequency vibration. This ultrasonic welding has the effect of firmly joining the edge regions of the honeycomb structure air-forming layer (120).

[0046] The bonding of the base layer (131) of the air-forming layer (120) and the polyurethane coating layer (130) is achieved by a hot-melt adhesive. The hot-melt adhesive melts when heated and exerts adhesive strength at high temperatures. The hot-melt adhesive is effective for bonding the non-woven fabric forming the base layer (131) and the polypropylene forming the air-forming layer (120).

[0047] A hot melt adhesive is applied to a lower honeycomb structure (121) that forms an air-forming layer (120), and a base layer (131) is placed overlappingly on the lower part of the honeycomb structure (121) to which the hot melt adhesive is applied, and then compressed. As the hot melt adhesive hardens, the air-forming layer (120) and the base layer (131) can be firmly bonded together.

[0048]

[0049] Meanwhile, FIG. 3 is an illustrative diagram showing various variations of the air-forming layer (120). FIG. 3(a) shows a form in which the air-forming layer (120a) is provided with a double-wall structure. The double-wall structure forms an air layer (123b) between the horizontal wall (123) and the vertical wall (123a) to absorb and block noise. As air is trapped in the air layer (123b) between the horizontal wall (123) and the vertical wall (123a), sound energy is reduced and absorbed. The double-wall structure has the advantages of being able to effectively absorb low-frequency noise, being easy to maintain due to its simple structure, and having a high thermal insulation effect. It is preferable that the double-wall structure be formed from aluminum material.

[0050] The air-forming layer (120b) of FIG. 3(b) is provided with a diagonal grid structure. The diagonal grid structure forms an air layer (125a) inside by arranging diagonal grids (125). The diagonal grids (125) are a structure that helps disperse and absorb sound while blocking airflow.

[0051] It is preferable that the diagonal grid structure be made of polyurethane material for sound dispersion and absorption.

[0052] The air-forming layer (120c) of FIG. 3 (c) is a foam air layer bonding structure. The foam air layer bonding structure is a structure in which air passages (127a) are bonded between porous foams (127), where the porous foams (127) partially absorb sound, and the air passages (127a) formed between them additionally absorb and block sound. The porous foams (127) can be formed from polyurethane foam or melamine foam.

[0053]

[0054] The sound-absorbing pad (100) of the present invention is provided with a multi-layer structure and absorbs and disperses noise through a combination of a PET felt layer (110) and an air-forming layer (120) of a honeycomb structure (121). The sound-absorbing pad (100) processes high-frequency noise, and the air-forming layer (120) processes low-frequency noise.

[0055] And, the top layer of polyurethane coating (130) combines with the base layer (131) to block noise from the outside.

[0056] Also, the polyurethane coating layer (130) increases resistance to external impact, moisture, and contamination, and, combined with the base layer (131), extends the lifespan of the sound-absorbing pad (100).

[0057] In addition, the total weight of the sound-absorbing pad (100) can be reduced depending on the selection of materials for the air-forming layer (120) and the base layer (131). In particular, since porous foam or fiber materials are very light, it is possible to produce a lightweight sound-absorbing pad (100).

[0058]

[0059] Meanwhile, FIG. 4 is a perspective view illustrating the configuration of a sound-absorbing pad (100a) according to another embodiment of the present invention. Compared to the sound-absorbing pad (100) of the preferred embodiment described above, the sound-absorbing pad (100a) of the other embodiment is provided with a sound-dispersing layer (140) instead of a polyurethane coating layer (130) on top of the air-forming layer (120).

[0060] The sound dispersion layer (140) is formed such that pyramid-shaped pyramid protrusions (141) protrude upward over the entire surface. The pyramid protrusions (141) formed on the surface disperse the sound energy by dispersing incident sound in various directions. This reduces direct reflection of sound from the surface, helping more sound to penetrate into the sound-absorbing pad (100).

[0061] In addition, the surface area is increased by the multiple pyramid protrusions (141). As the surface area increases, the contact area with sound increases, thereby improving the sound absorption effect.

[0062] In addition, if the sizes of the multiple pyramid protrusions (141) are provided differently, it is possible to effectively absorb sound in a wide frequency range, and in particular, the sound absorption performance against high-frequency noise can be improved.

[0063] In addition, if a sound dispersion layer (140) is formed on top of the honeycomb-structured air-forming layer (120), there is an advantage in that the structural strength can be reinforced and the sound absorption performance can also be improved.

[0064] The sound dispersion layer (140) is preferably made of polyurethane. Polyurethane is flexible, highly durable, and has the characteristic of being able to precisely form pyramidal irregularities. In addition, it has excellent water resistance and stain resistance, and has the effect of maximizing diffuse reflection of sound and protecting the air-forming layer (120) from external impact.

[0065] Here, the protrusions formed on the surface of the sound dispersion layer (140) can be provided in various shapes, such as pyramid shape, hemispherical shape, and irregular shape.

[0066]

[0067] As described above, the sound-absorbing pad according to the present invention is formed by bonding a PET felt layer, an air-forming layer, and a polyurethane coating layer in multiple layers. Each layer, provided with different materials and shapes, can effectively remove not only high-frequency noise but also low-frequency noise, thereby improving sound absorption performance.

[0068] In addition, the polyurethane coating layer prevents surface contamination, which has the effect of extending the lifespan of the sound-absorbing pad.

[0069]

[0070] The embodiments of the sound-absorbing pad of the present invention described above are merely illustrative, and those skilled in the art will readily understand that various modifications and equivalent alternative embodiments are possible therefrom. Therefore, it will be well understood that the present invention is not limited only to the forms mentioned in the detailed description above. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims. Furthermore, the present invention should be understood to include all modifications, equivalents, and substitutions within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A PET felt layer (110) formed of PET felt that absorbs high-frequency noise; The above PET felt layer (110) has an air-forming layer (120) with a certain thickness and containing an air layer (121a) to reduce sound energy and absorb low-frequency noise. An automotive sound-absorbing pad characterized in that the PET felt layer (110) is formed in a range of 5 to 10 mm and the air-forming layer (120) is formed in a range of 10 to 30 mm.

2. In Paragraph 1, The above air-forming layer (120) is characterized by being provided with any one of a honeycomb structure, a double-wall structure, a diagonal grid structure, and a foam air layer combined structure, in a sound-absorbing pad for automobiles.

3. In Paragraph 2, It includes a polyurethane coating layer (130) provided on the upper part of the air-forming layer (120) to prevent contamination from external impact, and The above polyurethane coating layer (130) is formed on a base layer (131) bonded to the upper part of the air-forming layer (120), and An automotive sound-absorbing pad characterized in that the above-mentioned polyurethane coating layer (130) is formed in a range of 0.5 to 2 mm.

4. In Paragraph 2, It further includes a sound dispersion layer (140) provided on the upper part of the air-forming layer (120) to reflect sound and disperse sound, and An automotive sound-absorbing pad characterized by having a plurality of pyramid-shaped pyramid protrusions (141) provided on the plate surface of the sound dispersion layer (140).

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