JP7572845B2 - Foam molded product and its manufacturing method, and sound source with cover - Google Patents

Description

This invention relates to a foam-molded product that can prevent sound from a sound source from being transmitted to the outside, a manufacturing method thereof, and a sound source with a cover.

In vehicles such as automobiles, ships, and aircraft, noises generated by various factors while driving enter the cabin, causing discomfort to the occupants and reducing comfort. For example, automobiles and other vehicles are equipped with sound sources such as engines and electric motors, or air conditioner compressors, and when sounds generated by the vehicle itself enter the cabin, they lead to a loss of quietness in the cabin. For this reason, measures to reduce noise are being taken in various places such as the engine room. For example, as a soundproofing measure for the engine room, a foam molded product such as a urethane foam formed by foaming and hardening a foaming raw material in a cavity formed in a closed molding die is placed facing the sound source such as the engine, so that the foam molded product blocks the sound from the sound source (for example, Patent Document 1).

Japanese Patent Application Publication No. 11-151994

Generally, sound sources such as engines and compressors have complex three-dimensional shapes with unevenness in various places. For this reason, when a soundproof foam molded product is placed to surround the sound source, sound leaks from the gap that occurs between the sound source and the foam molded product.

The present invention aims to provide a foam-molded product that can effectively prevent sound generated by a sound source from leaking out, a manufacturing method thereof, and a sound source with a cover.

In order to overcome the above problems and achieve the intended object, the first invention provides:
A method for producing a foam-molded product by foaming and curing a foaming raw material in a cavity formed in a closed molding die, comprising the steps of:
A molding die is provided with a support die and a slide die that is slidable relative to the support die, and is configured to be capable of molding an undercut-shaped portion of a foam-molded product that will become an undercut when demolded. A resin film is placed on the molding surface side of the undercut-shaped portion of the foam-molded product,
The gist of the method is that, with the boundary between the support die and the slide die of the molding die covered with the resin film, the foaming raw material is foamed and cured integrally with the resin film within the cavity.
In this way, by forming an undercut-shaped portion in the foam-molded product, when the foam-molded product is arranged so as to surround the sound source, it is possible to suppress the gap that occurs between the sound source and the foam-molded product. In other words, it is possible to increase the coverage rate of the sound source covered by the foam-molded product, and it is possible to prevent sound leakage from the gap and enhance the noise reduction effect. In addition, by integrally foaming and curing a resin film on the undercut-shaped portion side facing the sound source side in the foam-molded product, it is possible to improve the sound absorption characteristics of the foam-molded product, and it is possible to effectively prevent the sound of the sound source from leaking to the outside of the foam-molded product. In addition, by foaming and curing the foaming raw material in a state where the boundary between the support mold and the slide mold of the molding mold is covered with a resin film, it is possible to prevent the foaming raw material from entering the gap between the support mold and the slide mold. This makes it possible to reduce the cleaning man-hours for the molding mold, and to prevent the occurrence of malfunctions due to the foaming and curing of the foaming raw material that has entered the gap.

The second invention is
The gist of the invention is that, when the molding die is opened, the slide die is provided on the side of the die where the molding surface that forms the cavity is located on the lower side.
In this way, by providing a slide mold on the mold side where the molding surface that forms the cavity is located on the lower side, it becomes possible to demold the molded foam-molded product by operating the slide mold with the molding mold open, thereby simplifying the demolding process of the foam-molded product.

The third invention is
A suction portion is provided in the support mold so as to be connected to an undercut molding portion that molds an undercut shape portion of the foam molded product,
The gist of the method is that, with the molding die closed so that the resin film is positioned on the molding surface side of the undercut shaped portion, the undercut molding portion is sucked to draw the resin film toward the undercut molding portion, and then the foaming raw material is foamed and hardened within the cavity.
In this way, by sucking the undercut molding section and drawing the resin film into the undercut molding section, the foaming raw material is foamed and cured, so that the undercut shape section to which the resin film is bonded can be molded into a shape that matches the shape of the undercut molding section. In other words, by drawing the resin film into the undercut molding section in advance, it becomes possible to mold the entire foam-molded product, including the undercut shape section, into a predetermined shape.

The fourth invention is
The resin film is a thermoplastic resin, and the resin film is rendered plastically deformable by heating and then sucked.
In this way, by heating the resin film formed from thermoplastic resin and then sucking it, the shape-following ability of the resin film drawn into the undercut molding portion can be improved, and the undercut shape portion to which the resin film is joined can be more accurately molded into a shape that matches the shape of the undercut molding portion.

The fifth invention is
The gist is that it is a resin film formed to a thickness of 10 to 50 μm.
In this way, by forming the sound absorbing layer from a resin film formed to a thickness of 10 to 50 μm, the sound absorption coefficient in the low and mid frequency bands can be effectively increased.

The sixth invention is
a foam body having a concave accommodation recess formed therein that at least partially surrounds an outer periphery of the sound generating source;
an undercut-shaped portion that is integrally formed on an opening end side of the accommodating recess in the foam, extends toward the sound generating source when the sound generating source is accommodated in the accommodating recess, and becomes an undercut when the foam is demolded;
The present invention is characterized in that it comprises a sound absorbing layer formed of a resin film, the sound absorbing layer being provided so as to cover the foam and the side of the undercut shaped portion facing the accommodating recess.
In this way, by forming an undercut-shaped portion in the foam-molded product, when the foam-molded product is arranged so as to surround the sound source, it is possible to suppress the gap that occurs between the sound source and the foam-molded product. In other words, it is possible to increase the coverage rate of the sound source covered by the foam-molded product, and it is possible to prevent sound leakage from the gap and improve the noise reduction effect. In addition, by forming a sound-absorbing layer in which a resin film is bonded to the undercut-shaped portion side facing the sound source side in the foam-molded product, it is possible to improve the sound absorption characteristics of the foam-molded product, and it is possible to effectively prevent the sound of the sound source from leaking to the outside of the foam-molded product. In addition, by foaming and curing the foaming raw material in a state in which the boundary between the support mold and the slide mold of the molding mold is covered with a resin film, it is possible to prevent the foaming raw material from entering the gap between the support mold and the slide mold. This makes it possible to reduce the cleaning man-hours for the molding mold, and to prevent the occurrence of malfunctions due to the foaming and curing of the foaming raw material that has entered the gap.

The seventh invention is
The sound absorbing layer is formed of a resin film having a thickness of 10 to 50 μm.
In this way, by forming the sound absorbing layer from a resin film formed to a thickness of 10 to 50 μm, the sound absorption coefficient in the low and mid frequency bands can be effectively increased.

The present invention makes it possible to effectively prevent sound generated at a sound source from leaking to the outside.

1 is a schematic diagram of a vehicle in which a sound generating source is surrounded by a cover member according to the present invention. 1A is a schematic cross-sectional view of a sound generating source in a cover member, and FIG. 1B is a schematic cross-sectional view showing a state in which the cover member is separated. 10 is a schematic cross-sectional view showing a manufacturing process of the cover structure, illustrating a state in which a heated resin film is positioned between open foam molding dies. FIG. 4 is a schematic cross-sectional view showing a manufacturing process of the cover structure, illustrating a state in which the foam molding die is closed following the state shown in FIG. 3 . FIG. 5 is an enlarged view of part A in FIG. 4, in which (a) shows the state in which the resin film has been vacuum-suctioned, and (b) shows the state in which the foaming raw material has been foamed and cured. 10A to 10C are schematic cross-sectional views showing the manufacturing process of the cover structure, illustrating the state in which the cover structure has been demolded after foam molding. FIG. 13 is a graph showing the measurement results of normal sound absorption coefficient.

Next, the foam molded product and its manufacturing method according to the present invention, and the covered sound source will be described below with reference to the attached drawings, giving preferred examples. In this embodiment, as shown in FIG. 1, the compressor of an air conditioner located in a motor room MR provided at the front of the passenger compartment of an electric vehicle is used as the sound source CM, and the sound source CM is surrounded by a cover member 10.

2(a) and 2(b), the cover member 10 according to the embodiment is composed of a plurality of cover structures 11A and 11B as foam molded products, and is configured to surround the outer periphery of the sound generating source CM by combining the cover structures 11A and 11B to form a covered sound source P. In this embodiment, the cover member 10 is composed of two cover structures, a first cover structure 11A and a second cover structure 11B, and each of the cover structures 11A and 11B has a sound absorbing layer 20 laminated on the concave surface side of the foam 12 in which a concave storage recess 14 that forms an outer shell and can store the sound generating source CM is formed. Then, the first cover structure 11A and the second cover structure 11B are connected with their storage recesses 14 facing each other, and the cover member 10 is disposed in the motor room MR of the vehicle as a covered sound source P in which the sound generating source CM (compressor) is stored in the storage space 16 formed by the storage recesses 14 of both cover structures 11A and 10B. In addition, openings (not shown) are provided in appropriate positions on the first cover structure 11A and the second cover structure 11B in the cover member 10 to allow wiring and piping connected to the sound generating source CM housed in the housing space 16 to be inserted outside the cover member 10. Here, the first cover structure 11A and the second cover structure 11B differ in the presence or absence of an extension portion 18, but have the same other basic configurations, so the two cover structures will be described simply as cover structure 11 without distinguishing between them.

As shown in FIG. 2(b), the foam 12 of the cover structure 11 is formed in the storage recess 14 in a concave shape that opens to one side. An extension portion 18 is formed integrally with the foam 12 on the open end side of the foam 12, extending toward the sound generation source CM when the sound generation source CM is stored in the storage recess 14. In other words, the extension portion 18 is an undercut-shaped portion that becomes an undercut when the foam 12, which is foam-molded integrally with the extension portion 18, is demolded. In this embodiment, the extension portion 18, which is an undercut-shaped portion, is provided in the first cover structure 11A. Here, the shapes of the foam 12 and the storage recess 14 of the cover structure 11 are not particularly limited, but in this embodiment, they are formed in a hollow semi-cylindrical shape. In addition, examples of the foam forming the foam 12 and the extension 18 include polyurethane foam, polyolefin foam such as polyethylene foam and polypropylene foam, polystyrene foam, polyamide foam, polyester foam such as polyethylene terephthalate (PET) foam and polybutylene terephthalate (PBT), acrylic foam, phenol foam, polyvinyl chloride foam, polyimide foam, silicone resin foam, ethylene propylene diene rubber (EPDM) foam, styrene butadiene rubber (SBR) foam, nitrile butadiene rubber (NBR) foam, ethylene-vinyl acetate copolymer (EVA) foam, ethylene-acrylic acid copolymer foam, ethylene-ethyl acrylate copolymer (EEA) foam, etc. In addition, the foam can be formed from a dynamically crosslinked thermoplastic elastomer (TPV) in which rubber is crosslinked in the process of melt-kneading a thermoplastic resin and rubber. Examples of such TPV include a combination of PP and EPDM, and a combination of PP and NBR. In this embodiment, the foam is made of polyurethane foam.

2, the sound absorbing layer 20 is formed of a resin film F so as to cover the surfaces of the foam 12 and the extension 18 on the side of the storage recess 14. That is, the sound absorbing layer 20 is formed on the entire surface of the storage recess 14, including the extension 18, which becomes an undercut shape portion during foam molding. In this embodiment, the sound absorbing layer 20 is formed so as to cover the opening end surface of the foam 12, in addition to the surfaces of the foam 12 and the extension 18 on the side of the storage recess 14. That is, in the cover structure 11, the entire storage space 16 that contains the sound generating source CM is configured to be surrounded by the sound absorbing layer 20. Here, the sound absorbing layer 20 is formed by joining the foam 12 and the resin film F by integrally molding the thermoplastic resin film F during foam molding of the foam 12. The material of the thermoplastic resin film F that forms the sound absorbing layer 20 is not particularly limited, but conventionally known thermoplastic resin films such as polyester thermoplastic resin films, polyether thermoplastic resin films, thermoplastic urethane resin films, polyolefin resin films such as polyethylene and polypropylene, styrene resin films such as ABS resin, polyamide resin films such as 6-nylon, and acrylic resin films such as polymethyl methacrylate can be used. In this embodiment, the sound absorbing layer 20 is formed from a resin film F made of thermoplastic urethane, so that the resin film F can be effectively bonded during the foaming of the polyurethane foam that forms the foam 12.

The thickness of the resin film F that forms the sound absorbing layer 20 is not particularly limited, but it is preferable to form the sound absorbing layer 20 from a resin film F with a thickness of 10 μm to 50 μm. By forming the sound absorbing layer 20 from a resin film F with a thickness of 50 μm or less, it is possible to improve the conformability to the shape of the foam 12 and the extension portion 18, and by forming the sound absorbing layer 20 from a resin film F with a thickness of 10 μm or more, it is possible to effectively improve the sound absorbing performance, especially for sounds with frequencies around 500 Hz to 1000 Hz.

Next, a method for manufacturing the cover member 10 described above will be described. Here, the cover member 10 of this embodiment is constructed by connecting the first cover structure 11A and the second cover structure 11B, and the first cover structure 11A and the second cover structure 11B can basically be manufactured by a common manufacturing method. Therefore, in the following description, the two cover structures will be described without distinguishing between them, and only the different parts will be described. The foam molding die 50 according to this embodiment for molding the cover structure 11 includes a first die 52 for molding the storage recess 14 side of the cover structure 11 and a second die 60 for molding the outer surface side of the cover structure 11, and is configured so that the first die 52 and the second die 60 can be opened and closed relatively. Then, when the first die 52 and the second die 60 are closed (mold closed state), a cavity C (see FIG. 4) corresponding to the shape of the cover structure 11 to be molded is defined between the first die 52 and the second die 60. In this embodiment, the foam molding mold 50 is an upper mold in which the molding surface that forms the cavity C is located on the lower side when the first mold 52 is open, and a lower mold in which the molding surface that forms the cavity C is located on the upper side when the second mold 60 is open.

3, the first mold 52 for forming the first structure 11A includes a support mold 54 which is the main body of the first mold 52, and a slide mold 56 which can slide to a molding position and a protruding position relative to the support mold 54. That is, the slide mold 56 is provided on the mold side where the molding surface forming the cavity C is located on the lower side when the mold is opened. By positioning the slide mold 56 at the molding position relative to the support mold 54, an undercut molding part 58 matching the shape of the extension part 18 which becomes the undercut shape part of the cover structure 11 is formed between the support mold 54 and the slide mold 56, and the extension part 18 is formed by the foaming raw material entering the undercut molding part 58 when the foaming raw material is foamed and hardened. In addition, the support mold 54 is provided with suction parts 54b connected to a suction device (not shown) at multiple locations, and the suction device is operated to adsorb and hold the resin film F so as to follow the molding surface of the first mold 52 (support mold 54 and slide mold 56). Here, the suction portion 54b is provided so as to open to the undercut molding portion 58, and is configured so that the resin film F can be drawn into the undercut molding portion 58 by operating the suction device. In addition, the slide mold 56 is configured so as to be slidable relative to the support mold 54 so as to move away from the molded extension portion 18, and by sliding the slide mold 56 from the molding position to the protruding position after molding the cover structure 11, the slide mold 56 is separated from the extension portion 18, and the cover structure 11 can be demolded. This makes it possible to mold the extension portion 18, which is an undercut shaped portion, in the first structure 11A.

The manufacturing method of the cover member 10 includes a heating step of heating the resin film F that forms the sound absorbing layer 20, a covering step of covering the molding surface of the first mold 52 (support mold 54 and slide mold 56) with the resin film F, a foaming step of foaming the foaming raw material in the cavity C to form a foam, and a demolding step of demolding the molded foam. This heating step is a step in which a resin film F of a predetermined thickness formed from a thermoplastic resin is heated by a heater H to make it plastically deformable. At this time, as described above, it is preferable to use a resin film F with a thickness of 10 μm to 50 μm.

In the covering process, as shown in FIG. 4, after placing the heated resin film F between the first mold 52 and the second mold 60 that have been opened, the first mold 52 and the second mold 60 are closed. Here, when the first mold 52 and the second mold 60 are closed, the edge of the resin film F is sandwiched between the first mold 52 and the second mold 60, so that air does not enter the cavity C from the outside of the foam molding mold 50. Then, in this state, the suction device is operated to suck air between the first mold 52 (support mold 54 and slide mold 56) and the resin film F. That is, on the molding surface side of the first mold 52 that forms the extension portion 18 that becomes the undercut shape portion of the cover structure 11, the entire surface including the boundary between the support mold 54 and the slide mold 56 is arranged so as to be covered with the resin film F.

At this time, as shown in FIG. 5(a), in the support mold 54 of the first mold 52, the resin film F is deformed so as to be drawn into the inside of the undercut molding portion 58 by sucking air from the suction portion 54a formed to open into the undercut molding portion 58 constituting the cavity C for forming the extension portion 18 of the cover structure 11. At this time, the resin film F may be in full or partial contact with the molding surface of the undercut molding portion 58 in the first mold 52 (support mold 54 and slide mold 56), or the molding surface of the undercut molding portion 58 and the resin film F may be separated. In this way, by drawing the resin film F into the inside of the undercut molding portion 58, the foaming raw material foamed in the foaming process can be introduced to the undercut molding portion 58 side, and the extension portion 18 can be molded by following the shape of the undercut molding portion 58.

In the foaming process, the foaming raw material is foamed and cured in the cavity C to form a foam, with the molding surface of the first mold 52, including the boundary between the support mold 54 and the slide mold 56, covered with the resin film F. At this time, as shown in FIG. 5(b), the resin film F is pressed against the molding surface of the first mold 52 by the foaming pressure caused by the foaming of the foaming raw material in the cavity C, and the foam 12 is molded to have a shape that matches the shape of the cavity C, including the undercut molding portion 58 formed by the support mold 54 and slide mold 56 of the first mold 52, and the foam 12 and the resin film F are bonded together. As a result, the sound absorbing layer 20 is formed in which the resin film F is bonded to the extension portion 18 side, which is the undercut shape portion of the foam 12. The foaming raw material can be injected into the cavity C by opening the foaming mold 50 once after the covering process, or by providing a separate injection port (not shown) in the foaming mold 50 (for example, the first mold 52 or the second mold 60) and injecting the foaming raw material through the injection port while the foaming mold 50 is in a closed state.

It is also preferable to apply a release agent to the molding surface of the second mold 60 prior to the foaming step. Here, since the molding surface of the first mold 52 is covered with the resin film F in the covering step, the application of the release agent can be omitted. Here, the release agent application step may be performed with the foam molding mold 50 open before the covering step, or may be performed after the foam molding mold 50 is opened once after the covering step. Here, the release agent to be applied may be a conventionally known agent such as a wax-based, silicone-based, or fluorine-based agent that is suitable for the foam to be molded, and may be applied by a conventionally known method such as spray application or brush painting.

In the demolding process, the first mold 52 and the second mold 60 of the foam molding mold 50 are first opened. At this time, the extension portion 18 is fitted into the undercut molding portion 58 between the support mold 54 and the slide mold 56 and is in an engaged state, so that the mold is opened with the cover structure 11 attached to the molding surface side of the first mold 52. In this state, as shown in FIG. 6, the slide mold 56 is moved to a protruding position relative to the support mold 54 so that the slide mold 56 is separated from the extension portion 18 of the cover structure 11, and the cover structure 11 attached to the molding surface side of the first mold 52 is pushed out by the slide mold 56. That is, the cover structure 11 is removed from the first mold 52 by pushing out the slide mold 56 while allowing the extension portion 18 to come out of the undercut molding portion 58. Thereafter, the excess portion formed on the outer periphery of the cover structure 11 is cut off by a cutting means such as a cutter (not shown), thereby forming the cover structure 11 of a predetermined shape.

Then, the first cover structure 11A and the second cover structure 11B are fixed by facing the accommodation recesses 14 so as to accommodate the sound generating source CM in the accommodation space 16. This forms a covered sound source P in which the outer periphery of the sound generating source CM placed in the accommodation recess 14 shown in FIG. 2 is surrounded by the first cover structure 11A and the second cover structure 11B. Here, the first cover structure 11A and the second cover structure 11B may be bonded with an adhesive, or may be fixed by separately providing a fastener such as a metal fitting or a band.

According to the cover structure 11 (first cover structure 11A) and its manufacturing method of the present invention configured in this manner, and the covered sound source P in which the sound generating source CM is surrounded by the cover structure 11 (first cover structure 11A), the cover structure 11 can be formed in a shape that matches the external shape of the sound generating source CM by forming the extension portion 18 as an undercut shaped portion, and when the cover structure 11 is arranged to surround the sound generating source CM, the gap that occurs between the sound generating source CM and the cover structure 11 can be minimized. In other words, the coverage rate of the sound generating source CM covered by the cover structure 11 can be increased, and sound leakage from the gap between the cover structure 11 and the sound generating source CM can be prevented, thereby improving the noise reduction effect.

The cover structure 11 is also provided with a sound absorbing layer 20 formed of a resin film F on the entire surface on the sound generating source CM side. By forming the sound absorbing layer 20 with a resin film F bonded to the extension portion 18 side of the cover structure 11 facing the sound generating source CM in this manner, the sound absorbing characteristics of the cover structure 11 can be improved, and the sound of the sound generating source CM can be effectively prevented from leaking to the outside of the foam molded product. In particular, by forming the sound absorbing layer 20 from a resin film F formed to a thickness of 10 to 50 μm, the sound absorption rate in the low and mid frequency bands can be effectively increased. FIG. 7 shows the results of measuring the normal incidence sound absorption coefficient of each of the cover structure 11 in which the sound absorbing layer 20 is formed by bonding a resin film F made of 30 μm thermoplastic urethane to a foam 12 of 10 mm thickness formed from urethane foam, the cover structure 11 in which the sound absorbing layer 20 is formed by bonding a 12 μm resin film F to a foam 12 formed in the same manner, and the cover structure 11 formed only from the foam 12 formed in the same manner, measured in accordance with JIS A 1405-2. In this way, it can be seen that by forming the sound absorbing layer 20 with the resin film F, it is possible to effectively increase the sound absorption coefficient in the low to medium frequency bands. It can also be seen that it is possible to effectively absorb sounds in the frequency band lower than about 1 kHz, and a particularly good sound absorption coefficient can be achieved by forming the cover structure 11 by bonding a resin film F made of 30 μm thermoplastic urethane to form the sound absorbing layer 20. It can also be seen that by reducing the thickness of the resin film F, it is possible to increase the sound absorption coefficient in higher frequency bands.

In addition, by foaming and hardening the foaming raw material while the boundary between the support mold 54 and the slide mold 56 of the foam molding mold 50 is covered with a resin film F, it is possible to prevent the foaming raw material from entering the gap between the support mold 54 and the slide mold 56. This makes it possible to reduce the amount of work required to clean the foam molding mold 50, and also prevents malfunctions caused by the foaming and hardening of the foaming raw material that has entered the gap.

In addition, by vacuum-suctioning the undercut molding section 58 and foaming and hardening the foaming raw material while the resin film F is drawn into the undercut molding section 58, the foaming and hardening foaming raw material can be effectively guided to the undercut molding section 58. Therefore, the extension portion 18 that will become the circular cut shape portion can be molded in a shape that matches the shape of the undercut molding section 58, and the resin film F can be bonded to the extension portion 18 to reliably form the sound absorbing layer 20. In other words, by drawing the resin film F into the undercut molding section 58 in advance, it is possible to mold the entire cover structure 11, including the extension portion 18 that will become the undercut shape portion, into a predetermined shape. In addition, by foaming and hardening the foaming raw material while the resin film F is drawn into the undercut molding section 58, the resin film F drawn into the undercut molding section 58 can be pressed against the molding surface of the undercut molding section 58 by the foaming pressure when the foaming raw material is foamed and hardened.

In addition, by preheating the resin film F made of thermoplastic resin and then vacuum-suctioning it, the shape-following ability of the resin film F drawn into the undercut molding portion 58 can be improved. Therefore, the undercut shape portion where the resin film F is bonded to form the sound absorbing layer 20 can be more accurately molded in a shape that matches the shape of the undercut molding portion 58.

In addition, by providing a slide die 56 on the first die 52, in which the molding surface forming the cavity C is located on the underside, and operating the slide die 56 to move to a protruding position relative to the support die 54 while the foam molding die 50 is open, it becomes possible to detach the molded cover structure 11 from the first die 52 and demold it, which has the advantage of simplifying the demolding process of the foam molded product (cover structure 11).

(Example of change)
The present invention is not limited to the above-described embodiment, and may be modified as follows.
(1) The extension 18 that becomes the undercut shaped portion is formed in the first cover structure 11A, but similarly, the extension 18 that becomes the undercut shaped portion may be formed in the second cover structure 11B.
(2) A vacuum suction section is provided in the support mold 54 so as to connect to the undercut molding portion 58 of the foam molding mold 50. However, it is also possible to omit the vacuum suction section and make the resin film F conform to the shape of the undercut molding portion 58 using only the foaming pressure of the foaming raw material.
(3) In the embodiment, an example was shown in which one cover structure 11 has one extension 18 that forms an undercut shaped portion at one location, but it is also possible to provide a plurality of undercut shaped portions on the cover structure 11.
(4) The source of the sound is not limited to a compressor, but may be an electric motor or an engine, etc., and may be something that makes noise by itself or by coming into contact with other components.

11 Cover structure (foam molded product), 12 Foam,
18 Extension portion (undercut shaped portion), 20 Sound absorbing layer, 50 Foam molding die (molding die)
54 Support type, 54a Suction part (vacuum suction part), 56 Slide type
58 Undercut molding part, F Resin film, CM Sound source

Claims (6)

A manufacturing method for manufacturing a foam-molded product having a concave accommodating recess formed therein by foaming and curing a foaming raw material in a cavity formed in a closed molding die, comprising the steps of :
the molding die includes a first die for molding the accommodating recess and a second die for molding an outer surface side of the foam-molded product,
A resin film is placed on the molding surface side of the undercut-shaped portion of the foam-molded product , the first mold being provided with a support mold and a slide mold slidable relative to the support mold and configured to be capable of molding an undercut-shaped portion of the foam-molded product that will become an undercut when demolded;
In a state where the boundary between the support die and the slide die of the first die and the molding surface of the undercut shaped portion are covered with the resin film, a foaming raw material is foamed and cured together with the resin film in the cavity formed between the second die and the resin film , thereby providing a resin film so as to cover the foam and the accommodation recess side of the undercut shaped portion.
A method for producing a foam-molded product, comprising the steps of: The method for manufacturing a foam molded product according to claim 1, in which the slide mold is provided on the mold side where the molding surface forming the cavity is located on the lower side when the mold is open. The method for producing an expansion-molded product according to claim 1 or 2 , which is a resin film formed to a thickness of 10 to 50 μm. a foam body having a concave accommodation recess formed therein that at least partially surrounds an outer periphery of the sound generating source;
an undercut-shaped portion that is integrally formed on an opening end side of the accommodating recess in the foam, extends toward the sound generating source when the sound generating source is accommodated in the accommodating recess, and becomes an undercut when the foam is demolded;
A foam-molded product comprising: a sound-absorbing layer formed of a resin film, the sound-absorbing layer being provided so as to cover the foam and the side of the undercut shaped portion facing the accommodating recess. 5. The foam-molded product according to claim 4 , wherein the sound absorbing layer is formed of a resin film having a thickness of 10 to 50 μm. 6. A covered sound source, the periphery of which is surrounded by a plurality of cover structures including a cover structure formed from the foam molding according to claim 4 or 5 .

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