Soundproofing materials and vehicle soundproofing materials

Abstract

To provide a soundproof material and a vehicle soundproof material with an improved soundproof function.SOLUTION: A vehicle soundproof material 20 includes: a foam synthetic resin layer 21 having a plurality of through holes 21a formed along a thickness direction; and a first layer 22 for blocking openings of the through holes 21a.SELECTED DRAWING: Figure 4A

Description

[Technical Field]

[0001] The present invention relates to a soundproofing material and a soundproofing material for vehicles. [Background technology]

[0002] Patent Document 1 discloses a vehicle soundproofing material including a substrate 1, a skin material 3 attached to the front side of the substrate 1, which is the sound source / electromagnetic wave generating source side, and a conductive film 2 provided on the back side of the substrate 1. The substrate 1 may be made of inorganic fibers such as glass fiber, or a mat or felt made of organic fibers such as polyester, or a foam such as urethane. The skin material 3 may be a fibrous nonwoven fabric with excellent breathability, such as a nonwoven fabric made of polyester or polypropylene, glass cloth, or polyester film. The conductive film 2 may be made of a carbon fiber nonwoven fabric.

[0003] In addition, Patent Document 2 discloses a soundproofing material having 40 to 500 bottomless recesses 2A per m 2 and a surface layer material 3 laminated on one side of the core material 2, the surface layer material 3 having a layer formed from an extensible paper material 4 having an uneven surface, and a layer formed from an air-permeable porous material 6. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-180395 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-141405 Summary of the Invention [Problem to be solved by the invention]

[0005] The vehicle soundproofing material disclosed in the above-mentioned Patent Document 1 is capable of exhibiting soundproofing and electromagnetic wave absorbing functions, but there is a demand for further improvement in the soundproofing function. Also, the soundproofing material disclosed in the above-mentioned Patent Document 2 exhibits excellent buffering and sound absorbing properties, but there is a demand for further improvement in the buffering and sound absorbing properties (and therefore the soundproofing function).

[0006] The present invention has been made to solve the above-mentioned problems, and has as its object to provide a soundproofing material and a soundproofing material for vehicles with improved soundproofing function. [Means for solving the problem]

[0007] In order to solve the above problems, the soundproofing material of the present invention is characterized by comprising a foamed synthetic resin layer having a plurality of holes formed along the thickness direction, and a first layer that covers the openings of the holes.

[0008] According to the soundproofing material of the present invention, the holes formed in the foamed synthetic resin layer and the first layer can reduce a first sound of a first predetermined frequency, and the foamed synthetic resin layer can reduce a second sound of a second predetermined frequency. In this way, the soundproofing material can reduce at least two sounds, further improving the soundproofing function.

[0009] The soundproofing material according to the present invention preferably further comprises a second layer that closes the other openings of the holes and has higher breathability than the first layer, thereby making it possible to maintain the first sound reduction function of the first layer while maintaining the high design quality of the foamed synthetic resin layer.

[0010] In the soundproofing material according to the present invention, it is preferable that the depth of the holes can be changed to change the predetermined frequency of sound that can be reduced. In this way, it is possible to reliably reduce sound of a desired predetermined frequency simply by changing the depth of the holes formed in the foamed synthetic resin layer.

[0011] In the soundproofing material according to the present invention, the depth of the holes is preferably set to a value greater than the diameter of the holes, which makes it possible to accommodate sounds of multiple predetermined frequencies for the same hole diameter, and ultimately makes it possible for a soundproofing material of a given area to accommodate sounds of multiple predetermined frequencies.

[0012] In the soundproofing material according to the present invention, it is preferable that the depths of the holes can be set to different values, which makes it possible for a single soundproofing material to accommodate sounds of a plurality of predetermined frequencies.

[0013] In the soundproofing material according to the present invention, it is preferable that the holes are capable of reducing a first sound having a first predetermined frequency, and the foamed synthetic resin layer is capable of reducing a second sound having a second predetermined frequency, so that the soundproofing material can reduce both the first sound and the second sound.

[0014] In the soundproofing material according to the present invention, it is preferable to provide a high hole density region where the density of holes is high and a low hole density region where the density of holes is low. This makes it possible to simply and reliably separate and provide a high hole density region with a relatively high soundproofing (sound absorption) function for the first sound and a low hole density region with a relatively high soundproofing (sound absorption) function for the second sound.

[0015] In the soundproofing material according to the present invention, it is preferable that the high-hole-density region is disposed corresponding to a first sound source that generates the first sound, and the low-hole-density region is disposed corresponding to a second sound source that generates the second sound. This makes it possible to efficiently reduce the first sound emitted from the first sound source and the second sound emitted from the second sound source.

[0016] The vehicle soundproofing material according to the present invention is characterized in that the above-mentioned soundproofing material is used in a vehicle, thereby providing a vehicle soundproofing material having the effects of the above-mentioned soundproofing material. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a soundproofing material and a soundproofing material for vehicles with improved soundproofing function. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a side view showing an embodiment of a vehicle M to which a vehicle soundproofing material 20 according to the present invention is applied. [Figure 2] 1 is a plan view showing an embodiment of a vehicle M to which a vehicle soundproofing material 20 according to the present invention is applied. [Figure 3] 1 is a plan view showing a vehicle soundproofing material 20 (hood insulator 20a). [Figure 4A] FIG. 4 is a cross-sectional view taken along line 4A-4A shown in FIG. [Figure 4B] FIG. 4 is a cross-sectional view taken along line 4B-4B shown in FIG. [Figure 5A] FIG. 10 is a plan view showing a vehicle soundproofing material 120 according to a modified example. [Figure 5B] FIG. 5B is a cross-sectional view taken along line 5B-5B shown in FIG. 5A. [Figure 6A] 10A to 10C are cross-sectional views showing a method for manufacturing a vehicle soundproofing material 120 according to a modified example. [Figure 6B] 10A to 10C are cross-sectional views showing a method for manufacturing a vehicle soundproofing material 120 according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of a soundproofing material and a soundproofing material for a vehicle according to the present invention will be described with reference to the drawings. However, the present invention is not limited to this embodiment, and can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0020] As shown in Figures 1 and 2, a vehicle soundproofing material (soundproofing material) 20 is attached to a vehicle M. The vehicle M has a body 10. The body 10 has an engine compartment 11, a passenger compartment 12, and a trunk compartment 13, which are each partitioned.

[0021] The engine compartment 11 is a room in which a drive source for driving the vehicle M is mounted (i.e., it may be referred to as a drive source accommodation room). The engine compartment 11 is equipped with an engine 14, which is an internal combustion engine for driving (running) the vehicle M, a motor 15 for driving (running) the vehicle M, and a power control unit (hereinafter, sometimes referred to as PCU) 16, which is an inverter device for controlling the motor 15. The passenger compartment 12 is a room for passengers to board, and is equipped with seats in which the passengers can sit. The engine compartment 11 and the passenger compartment 12 are separated by a dash panel 17.

[0022] The vehicle M is a hybrid vehicle equipped with multiple (two or more) drive sources (an engine 14 and a motor 15). Hybrid vehicles can be of a parallel type, in which multiple drive sources are used to drive the wheels, or a series type, in which the engine 14 is used only to drive a generator (mounted separately from the motor 15) (not to drive the wheels), and the generated electricity is used to drive the motor 15, which then drives the wheels, thereby propelling the vehicle. In this embodiment, the vehicle M is a parallel type hybrid vehicle.

[0023] The engine 14 may be a gasoline engine that uses gasoline as fuel or a diesel engine that uses diesel as fuel. The motor 15 functions as an electric motor that drives the wheels using power supplied from the battery 18, or as a generator that generates power in the motor 15 using the rotation of the wheels to charge (regenerate) the battery 18. The PCU 16 (inverter device) is electrically connected between the battery 18 and the motor 15, and is a device that converts DC power to AC power and converts AC power to DC power.

[0024] The noise of the engine 14 includes mechanical noise such as piston smacking and valve train smacking, combustion noise caused by combustion pressure, intake noise caused by airflow in the intake system, exhaust protrusion noise in the exhaust system, etc. The noise of the motor 15 includes magnetic excitation noise, electromagnetic noise, mechanical noise, etc.

[0025] The vehicle M may be an electric vehicle equipped with only the motor 15 as a driving source. The electric vehicle is equipped with the motor 15, the PCU 16, the battery 18, and the like.

[0026] The vehicle soundproofing material 20 is a component that is used (mounted) in the vehicle M to absorb (or reduce, block) sound (noise). Examples of the vehicle soundproofing material 20 include a hood insulator 20a provided on the back side of the hood 19 that covers the engine compartment 11, and a dash insulator 20b provided on the dash panel 17. Note that the soundproofing material is a component that is used in objects other than the vehicle M to absorb (or reduce, block) sound (noise). Examples of objects other than the vehicle M include devices, equipment, and electrical appliances that include electrical components that generate relatively high-frequency noise, such as motors, inverter devices, transformers, and solenoid valves.

[0027] The hood insulator 20a reduces (absorbs) and blocks sounds (noise) generated from sound sources such as the engine 14, motor 15, and PCU 16 provided in the engine compartment 11. The dash insulator 20b reduces (absorbs) sounds (noise) generated from sound sources such as the engine 14, motor 15, and PCU 16 provided in the engine compartment 11, and blocks the sounds from entering the passenger compartment 12.

[0028] As an example of the vehicle soundproofing material 20, a hood insulator 20a will be described. As shown in FIG. 3, the hood insulator 20a has a high-hole-density region 20a1, which is a region where the density of the through holes 21a is high, and a low-hole-density region 20a2, which is a region where the density of the through holes 21a is low. In this embodiment, the region where no through holes 21a are provided is the low-hole-density region 20a2, and the region where the through holes 21a are provided is the high-hole-density region 20a1. As will be described later, the through holes 21a are through holes formed in the thickness direction of the foamed synthetic resin layer 21. The high-hole-density region 20a1 may also be defined as a region where the density of the through holes 21a is higher than that of the low-hole-density region 20a2.

[0029] The high-hole-density region 20a1 is disposed in correspondence with a first sound source that generates a first sound having a first predetermined frequency. In this embodiment, for example, the first sound source is the motor 15, and the first predetermined frequency is a frequency of 5 kHz to 20 kHz (the upper limit of the human audible range), in particular a frequency of 5 kHz to 10 kHz. The low-hole-density region 20a2 is disposed in correspondence with a second sound source that generates a second sound having a second predetermined frequency. In this embodiment, for example, the second sound source is the engine 14, and the second predetermined frequency is a frequency less than 5 kHz, in particular a frequency of 1 kHz to 2 kHz.

[0030] As shown in FIGS. 4A and 4B, the hood insulator 20a includes a foamed synthetic resin layer 21, a first layer 22, and a second layer 23.

[0031] The foamed synthetic resin layer 21 is formed by foaming a foamed synthetic resin raw material. The foamed synthetic resin layer 21 is a porous synthetic resin with fine air bubbles trapped inside, and is a foam with a synthetic resin skeleton. For the foamed synthetic resin layer 21, urethane foam (polyurethane foam) made from polyurethane can be used. The urethane foam may be soft polyurethane foam, hard polyurethane foam, or semi-hard polyurethane foam. For the foamed synthetic resin layer 21, foamed synthetic resins such as polyethylene foam, EVA foam, and melamine resin foam can be used. Polyethylene foam is made from polyethylene, and EVA foam is made from ethylene vinyl acetate copolymer. Melamine resin foam is made from a synthetic resin produced by polycondensation of melamine and formaldehyde.

[0032] For example, the urethane foam raw material contains polyol, polyisocyanate, a blowing agent, a catalyst, etc., and is a known material that foams by the reaction of polyol and polyisocyanate, and has a density of 10 kg / m 3 ~95kg / m 3 It is preferable to use a material that forms a urethane foam of 10 kg / m 3 ~40kg / m3 The thickness of the foamed synthetic resin layer 21 is preferably about 1 mm to 50 mm, and more preferably about 20 mm to 30 mm.

[0033] The foamed synthetic resin layer 21 is preferably capable of reducing the second sound of the second predetermined frequency. The foamed synthetic resin layer 21 is preferably capable of reducing sounds in a frequency band below 5 kHz (a relatively low frequency band), and more preferably capable of reducing sounds in a frequency range of 1 kHz to 2 kHz.

[0034] The foamed synthetic resin layer 21 has a plurality of through holes 21a (corresponding to "holes" in the claims) formed along the thickness direction. The holes in the foamed synthetic resin layer 21 include not only through holes that penetrate the foamed synthetic resin layer 21 in the thickness direction, but also recesses that do not penetrate the foamed synthetic resin layer 21.

[0035] It is preferable that the through holes 21a can reduce the first sound of a first predetermined frequency that is different from the second predetermined frequency, while the foamed synthetic resin layer 21 can reduce the second sound of a second predetermined frequency. In this embodiment, it is preferable that the through holes 21a can reduce sounds in a frequency band of 5 kHz to 20 kHz (relatively high frequency band), and more preferably can reduce sounds in a frequency range of 5 kHz to 10 kHz.

[0036] The through-hole 21a is preferably formed in a circular shape, but may be formed in a shape other than a circle (for example, a polygonal shape (including a triangular shape and a rectangular shape), or an elliptical shape).

[0037] The depth d of through-hole 21a is set to be an odd multiple of one-fourth the wavelength λ of the sound wave (sound) (d=(2k-1)×(λ / 2), where k is a natural number). According to this, the sound wave (incident wave) that enters through-hole 21a is reflected at the closed end and output (emitted) from through-hole 21a, but the output sound wave (output wave) is delayed in phase by (2k-1) / 2 wavelengths compared to the incident wave as it travels back and forth through through-hole 21a. In other words, the output wave is a sound wave with an opposite phase to the incident wave. The incident wave and the output wave are combined and cancel each other out, thereby achieving a sound-canceling effect.

[0038] Furthermore, since the wavelength λ of a sound wave is 1 / (frequency T of the sound wave), the depth d of through hole 21a can be expressed as d=(2k-1)×(½T). Therefore, by changing the depth of through hole 21a, it is possible to change the predetermined frequency of sound (sound waves) that can be reduced.

[0039] Furthermore, it is preferable that the depth d of the through-hole 21a is set to a value larger than the hole diameter R of the through-hole 21a.

[0040] In this embodiment, the through holes 21a are arranged in a square lattice pattern, as shown in Fig. 3. The square lattice pattern is one form of a planar lattice pattern, in which points are arranged at equal intervals in rows that are arranged at equal intervals, and each row is not staggered, and a triangle formed by three adjacent points is a right-angled isosceles triangle (in other words, a rectangle formed by four adjacent points is a square). In this case, the interval between the through holes 21a is preferably set to a value (a predetermined value) greater than the hole diameter R.

[0041] In addition to square lattices, planar lattices include rhombic lattices (diamond lattices, isosceles triangular lattices), regular triangular lattices (hexagonal lattices), rectangular lattices, and parallelepiped lattices. In a rhombic lattice, points are arranged at equal intervals in rows that are evenly spaced, and each row is shifted alternately by half the spacing, and the triangles formed by three adjacent points are isosceles triangles. In a regular triangular lattice, points are arranged at equal intervals in rows that are evenly spaced, and each row is shifted alternately by half the spacing, and the triangles formed by three adjacent points are equilateral triangles. In a rectangular lattice, points are arranged at equal intervals in rows that are evenly spaced, and each row is not shifted alternately, and the triangles formed by three adjacent points are right-angled triangles. A parallelepiped lattice has points arranged at equal intervals on rows that are evenly spaced, and each row is offset by a specified amount (except half) of the spacing between the rows, and the triangles formed by three adjacent points are scalene triangles.

[0042] The first layer 22 is laminated on one surface (the surface (back surface) on the hood 19 side) of the foamed synthetic resin layer 21. The first layer 22 is preferably formed of a fabric or material (hereinafter, may be referred to as fabric, etc.) such as a woven fabric, knitted fabric, or nonwoven fabric. The first layer 22 is more preferably formed of a material with relatively low air permeability. Low air permeability means low breathability, which may also be said to have high air resistance. In this embodiment, the first layer 22 is more preferably formed of a nonwoven fabric. Incidentally, a woven fabric is generally a fabric woven using two threads, a warp thread and a weft thread. Furthermore, a nonwoven fabric is a sheet-like fabric or material made by intertwining fibers without weaving them.

[0043] A nonwoven fabric is a sheet-like fabric made by intertwining fibers without weaving or knitting them, such as a fiber sheet, web, or batt, in which the fibers are oriented unidirectionally or randomly and are bonded together by entanglement and / or welding (fusion) and / or adhesion. Nonwoven fabrics include staple fiber nonwoven fabrics such as needle-punched nonwoven fabrics, chemical-bonded nonwoven fabrics, thermal-bonded nonwoven fabrics, and spunlaced nonwoven fabrics, as well as long fiber nonwoven fabrics such as spunbonded nonwoven fabrics, melt-blown nonwoven fabrics, and flash-spun nonwoven fabrics.

[0044] Needle-punched nonwoven fabrics are nonwoven fabrics made by entangling fibers with reciprocating needles. Chemical-bonded nonwoven fabrics are made by bonding fibers using adhesives. Thermal-bonded nonwoven fabrics are made using heat-welded fibers. Spunlaced nonwoven fabrics are made by entangling fibers in a web using a high-pressure water jet without using a binder (adhesive). Fibers that can be used to form short-fiber nonwoven fabrics include synthetic fibers made from polyester, PP (polypropylene), polyolefin resins such as ethylene-propylene copolymers, and the like.

[0045] Spunbond nonwoven fabrics are nonwoven fabrics made by melting or dissolving a polymer and then spun from a nozzle to form continuous fibers (filaments) that are then layered on a moving screen, using one or more bonding methods. Meltblown nonwoven fabrics are made by spinning a polymer into a high-velocity hot gas stream to form fibers, cooling them, and then collecting them on a moving screen, using one or more bonding methods. Flash-spun nonwoven fabrics are made by spinning a polymer solution from a nozzle under certain conditions, evaporating the solvent immediately after spinning, and layering these fibers on a moving screen, using one or more bonding methods to form highly fibrillated filaments. The polymers mentioned above are high-molecular organic compounds, such as polyamide, polyethylene, polypropylene, and polyurethane, which are thermoplastic resins (synthetic resins).

[0046] In this embodiment, the nonwoven fabric used in the first layer 22 is preferably formed of a spunbond nonwoven fabric. 2 It is preferable that:

[0047] The first layer 22 preferably has lower breathability than the foamed synthetic resin layer 21. The first layer 22 also preferably has lower breathability than the second layer 23 described below.

[0048] The first layer 22 closes one opening of the through hole 21a. This forms a recess (passage) 40 in which one side of the through hole 21a is closed and the other side is open. The recess 40 has a closed end 41 and a wall surface 42. The closed end 41 is formed by the first layer 22, i.e., the surface of the first layer 22. The wall surface 42 is formed by the inner wall surface of the through hole 21a. The recess 40 functions as a passage through which sound waves (incident waves) entering through the opening can travel. The sound waves that further travel are reflected by the closed end 41, and the reflected waves (output waves) are output from the opening. At this time, as described above, sound waves of a predetermined frequency that has a predetermined relationship with the depth d of the recess 40 are reduced by combining the incident wave and the output wave and canceling each other out. In this way, the recess 40 functions as a sound-deadening section that reduces sound waves of a predetermined frequency. The predetermined relationship is expressed as frequency T = (2k-1) × (1 / 2d).

[0049] In this way, the soundproofing material (vehicle soundproofing material 20) has a sound-deadening portion (recess 40) that reduces sound of a predetermined frequency. The sound-deadening portion is formed by an inner wall surface 42 of a through hole 21a formed in the foamed synthetic resin layer 21 along the thickness direction, and a closed end 41 (low-permeability portion) that closes the through hole 21a and has relatively low air permeability.

[0050] In this embodiment, the first layer 22 is a single layer member laminated so as to cover the entire foamed synthetic resin layer 21, but it may be in any form as long as it blocks one opening of the through hole 21a, for example, it may be in a shape that blocks only the opening of the through hole 21a.

[0051] The second layer 23 is laminated on the other surface (the surface (surface) on the motor 15 side) of the foamed synthetic resin layer 21. The second layer 23 is preferably formed from a fabric or material (hereinafter sometimes referred to as fabric, etc.) such as woven fabric, knitted fabric, or nonwoven fabric. The second layer 23 is more preferably formed from a material with relatively high breathability. High breathability means high breathability, which may also be said to have low airflow resistance. In this embodiment, the second layer 23 is more preferably formed from a nonwoven fabric.

[0052] In this embodiment, the nonwoven fabric used in the second layer 23 is preferably formed of a spunbond nonwoven fabric. 2 It is preferable that:

[0053] The second layer 23 preferably has higher breathability than the first layer 22. Also, the second layer 23 preferably has higher breathability than the foamed synthetic resin layer 21. Furthermore, the second layer 23 closes the other opening of the through hole 21a. Because the second layer 23 is highly breathable, it does not impede the entry of sound through the opening of the recess 40 or the output of reflected waves. Therefore, the recess 40 functions as a sound-deadening section that reduces sound of a predetermined frequency. Furthermore, because the second layer 23 is laminated so as to cover the entire foamed synthetic resin layer 21, it is possible to maintain a high level of design quality for the vehicle soundproofing material 20.

[0054] (Manufacturing method (process)) Next, a manufacturing method of the vehicle soundproofing material 20 will be described. First, the foamed synthetic resin layer 21, the first layer 22, and the second layer 23 are manufactured. The foamed synthetic resin layer 21 is formed to a predetermined thickness and a predetermined shape, and then a predetermined number of through holes 21a of a predetermined shape are formed in the high hole density region 20a1. Note that the foamed synthetic resin layer 21 may be formed with a predetermined number of through holes 21a of a predetermined shape when it is molded using a mold. Note that the first layer 22 and the second layer 23, which are nonwoven fabrics, are manufactured by a commonly known method for manufacturing nonwoven fabrics.

[0055] Next, the first layer 22 is laminated on one surface of the foamed synthetic resin layer 21, and the second layer 23 is laminated on the other surface of the foamed synthetic resin layer 21, and then the resulting mixture is hot-press molded to produce the vehicle soundproofing material 20. The foamed synthetic resin layer 21 is attached to the first layer 22 and the second layer 23 by welding or by using an adhesive.

[0056] (Actions and Effects of the Embodiments) The vehicle soundproofing material 20 (soundproofing material) according to the above-described embodiment comprises a foamed synthetic resin layer 21 having a plurality of through holes 21a (holes) formed along the thickness direction, and a first layer 22 that covers the openings of the through holes 21a.

[0057] According to the vehicle soundproofing material 20 (soundproofing material), the through holes 21a formed in the foamed synthetic resin layer 21 and the first layer 22 can reduce a first sound of a first predetermined frequency, and the foamed synthetic resin layer 21 can reduce a second sound of a second predetermined frequency. In this way, the vehicle soundproofing material 20 (soundproofing material) can reduce at least two sounds, thereby further improving the soundproofing function. As a result, it is possible to provide a soundproofing material and a vehicle soundproofing material with improved soundproofing function. Furthermore, it is possible to provide a vehicle soundproofing material 20 (soundproofing material) that is lightweight and easy to use and has improved soundproofing function. Note that, in this specification, the xth sound, such as the first sound or the second sound, can be referred to as the xth sound wave, such as the first sound wave or the second sound wave, and in this case, "reducing the xth sound" can be referred to as "attenuating the xth sound wave."

[0058] Furthermore, the vehicle soundproofing material 20 (soundproofing material) preferably further includes a second layer 23 that closes the other openings of the through-hole 21a and has higher breathability than the first layer 22. This makes it possible to maintain the first sound reduction function of the first layer 22 while maintaining the high design quality of the foamed synthetic resin layer 21.

[0059] Furthermore, in the vehicle soundproofing material 20 (soundproofing material), it is preferable that the predetermined frequency of sound that can be reduced can be changed by changing the depth of the through holes 21 a. This makes it possible to reliably and easily reduce sound of a desired predetermined frequency simply by changing the depth of the through holes 21 a formed in the foamed synthetic resin layer 21.

[0060] Furthermore, in the vehicle soundproofing material 20 (soundproofing material), it is preferable that the depth of the through hole 21a is set to a value greater than the hole diameter of the through hole 21a. This makes it possible to accommodate sounds of multiple predetermined frequencies for the same hole diameter, and ultimately makes it possible for the vehicle soundproofing material 20 (soundproofing material) of a predetermined area to accommodate sounds of multiple predetermined frequencies. As a result, it becomes possible to accommodate sounds of multiple predetermined frequencies in a limited space.

[0061] Furthermore, in the vehicle soundproofing material 20 (soundproofing material), it is preferable that the through holes 21a can reduce a first sound of a first predetermined frequency, and the foamed synthetic resin layer 21 can reduce a second sound of a second predetermined frequency. This allows the vehicle soundproofing material 20 (soundproofing material) to reduce both the first sound and the second sound.

[0062] Furthermore, it is preferable that the vehicle soundproofing material 20 (soundproofing material) be provided with a high-hole-density region 20a1, which is a region with a high density of through holes 21a, and a low-hole-density region 20a2, which is a region with a low density of through holes 21a. This makes it possible to simply and reliably separate and provide the high-hole-density region 20a1, which has a relatively high soundproofing (sound-absorbing) function for the first sound, and the low-hole-density region 20a2, which has a relatively high soundproofing (sound-absorbing) function for the second sound.

[0063] Furthermore, in the vehicle soundproofing material 20 (soundproofing material), it is preferable that the high-hole-density region 20a1 is disposed corresponding to a first sound source that generates a first sound, and the low-hole-density region 20a2 is disposed corresponding to a second sound source that generates a second sound. This makes it possible to efficiently reduce the first sound emitted from the first sound source and also efficiently reduce the second sound emitted from the second sound source. As a result, it is possible to achieve both highly efficient reduction of the first sound emitted from the first sound source and highly efficient reduction of the second sound emitted from the second sound source.

[0064] Furthermore, the vehicle soundproofing material 20 (soundproofing material) is preferably used in a vehicle, which makes it possible to provide a vehicle soundproofing material having the above-mentioned effects.

[0065] (Variation) Furthermore, a vehicle soundproofing material 120 according to a modified example will be described with reference to Figures 5A and 5B. The vehicle soundproofing material 120 has two types of through holes 21a, 21b with different depths. In this case, the vehicle M is an electric vehicle equipped with two motors that emit different predetermined frequencies. Note that the electric vehicle may also be equipped with one motor and an inverter device that emits a different predetermined frequency from the motor. In any case, it is desirable for the vehicle to be equipped with multiple types of sound sources that emit different predetermined frequencies.

[0066] The vehicle soundproofing material 120 includes a foamed synthetic resin layer 121, a first layer 22, and a second layer 123. The foamed synthetic resin layer 121 has through holes 21a and 21b. The depth of the through hole 21b is set to a value smaller than the depth of the through hole 21a. The through holes 21a and 21b are arranged alternately. The second layer 123 is formed in an uneven shape corresponding to the unevenness of the other surface of the foamed synthetic resin layer 121.

[0067] Next, a manufacturing method of the vehicle soundproofing material 120 will be described. First, the foamed synthetic resin layer 21, the first layer 22, and the second layer 23 are manufactured. The foamed synthetic resin layer 21 is formed to a predetermined thickness and a predetermined shape, and then a predetermined number of through holes 21a of a predetermined shape are formed in the high hole density region 20a1. Note that the foamed synthetic resin layer 21 may be molded to form a predetermined number of through holes 21a of a predetermined shape. Note that the first layer 22 and the second layer 23, which are nonwoven fabrics, are manufactured by a commonly known method for manufacturing nonwoven fabrics.

[0068] Next, the first layer 22 is laminated on one side of the foamed synthetic resin layer 21, and the second layer 23 is laminated on the other side of the foamed synthetic resin layer 21. Thereafter, as shown in FIG. 6A, the resulting product is hot-press molded using dies 31 and 32 to produce the vehicle soundproofing material 120 (see FIG. 6B). The die 32 has a desired unevenness formed therein. The depth of the through holes 21a and 21b can be easily and reliably formed to a desired value when the vehicle soundproofing material 120 is pressed using the dies 31 and 32. In this way, the depths of the through holes 21a and 21b can be set to different values. Alternatively, the foamed synthetic resin layer 121 may first be formed to a predetermined thickness and shape using a die, and then the first layer 22 and the second layer 23 may be welded and attached with an adhesive.

[0069] In the vehicle soundproofing material 120 (soundproofing material), the depth of each through hole 21a can be set to a different value, which makes it possible for one vehicle soundproofing material 20 (soundproofing material) to deal with sounds of a plurality of predetermined frequencies (noise reduction / sound absorption).

[0070] Furthermore, in the above-described embodiment and modified examples, the sound absorbing section 40 has the closed end 41 and the wall surface 42, but an extension section may be further provided by extending the wall surface 42 radially outward. A reflected wave is generated in the extension section, and the reflected wave and the incoming wave cancel each other out within the sound absorbing section 40, thereby further achieving the effect of sound absorbing.

[0071] Furthermore, the vehicle soundproofing material 20, 120 (soundproofing material) may be configured to surround an object that is a sound source (such as a motor or an inverter device). In this case, it is necessary to ensure that the through-hole 21a is not crushed. For example, if the soundproofing material needs to be folded, it is necessary to avoid providing the through-hole 21a at the folded portion. [Explanation of symbols]

[0072] 14...engine, 15...motor, 20...vehicle soundproofing material (soundproofing material), 20a1...high hole density region, 20a2...low hole density region, 21...foamed synthetic resin layer, 21a...through hole (hole), 22...first layer, 23...second layer, M...vehicle.

Claims

1. a foamed synthetic resin layer having a plurality of holes formed along a thickness direction; a first layer that closes the opening of the hole; It consists of only two layers, A soundproofing material characterized by satisfying any one of the following (1) to (3) and also satisfying any one of the following (4) to (6). (1) The first layer is selected from a woven fabric, a knitted fabric, a nonwoven fabric, and a fabric. (2) The foamed synthetic resin layer is compressed in the thickness direction so as to have an uneven shape on the side opposite to the first layer, the plurality of holes includes a first hole and a second hole adjacent to each other, The foamed synthetic resin layer located between the first hole and the second hole has a different compression rate on the first hole side and the second hole side. (3) The depth of the hole is set to a value greater than the diameter of the hole, The depth of each hole can be set to a different value. (4) The surface of the foamed synthetic resin layer on the side of the first layer is flat. (5) The first layer closes all openings of the plurality of holes. (6) The plurality of holes penetrate the foamed synthetic resin layer in the thickness direction.

2. a foamed synthetic resin layer having a plurality of holes formed along a thickness direction; a first layer that closes the opening of the hole; a second layer closing the other opening of the hole; It consists of only three layers: the first layer is selected from a woven fabric, a knitted fabric, a nonwoven fabric, or a textile; The soundproofing material is characterized in that the second layer is selected from woven fabric, knitted fabric, nonwoven fabric, or fabric.

3. a foamed synthetic resin layer having a plurality of holes formed along a thickness direction; a first layer that closes the opening of the hole; Equipped with the foamed synthetic resin layer is compressed in the thickness direction so as to have an uneven shape on the side opposite to the first layer, the plurality of holes includes a first hole and a second hole adjacent to each other, the foamed synthetic resin layer located between the first hole and the second hole has a compression rate different between the first hole side and the second hole side, a second layer that closes another opening of the hole; A soundproofing material characterized in that the entire second layer has an uneven shape that matches the shape of the foamed synthetic resin layer.

4. a foamed synthetic resin layer having a plurality of holes formed along a thickness direction; a first layer that closes the opening of the hole; Equipped with the holes are capable of reducing a first sound of a first predetermined frequency; the foamed synthetic resin layer is capable of reducing a second sound having a second predetermined frequency; A soundproofing material characterized in that it is provided with a high hole density region, which is a region where the density of holes is high, and a low hole density region, which is a region where the density of holes is low.

5. the high hole density region is disposed in correspondence with a first sound source that generates the first sound, The soundproofing material according to claim 4 , wherein the low hole density region is disposed in correspondence with a second sound source that generates the second sound.

6. A soundproofing material for a vehicle, comprising the soundproofing material according to any one of claims 1 to 5, used in a vehicle.

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