JP2015109534A - Injection molding of speaker grille and method for molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding of a speaker grille formed by integrating an attachment body with a metal plate by injection molding, and also to provide a method for molding the same.SOLUTION: Ultrafine uneven surface treatment is applied to a raw material of a metal plate 2 in which the punched cave is processed and which is applied to a predetermined shape. The metal plate 2 subjected to this ultrafine uneven surface treatment is inserted into a metal mold 4. A thermoplastic resin composition is injected into a cavity 5 in the closed metal mold 4 to form an attachment body 3 therein. As a result, a speaker grille 1 is formed by integrating the metal plate 2 subjected to the ultrafine uneven surface treatment and the attachment body 3. When the speaker grilles 1 is attached to a speaker unit, resin can be fixed or fused to each other via the attachment body 3.

Description

  The present invention relates to an injection molded body of a speaker grill made of a metal material and a molding method thereof. More specifically, the present invention relates to an injection molded body of a speaker grill formed by injecting a synthetic resin onto a punched metal plate so as to integrate a mounting body, and a molding method thereof.

  Punching metal punched on a metal plate such as a steel plate, stainless steel, or aluminum alloy is often used for building materials, housings and parts of electrical appliances. For example, a punching metal is used for a speaker grill disposed on the front surface of the speaker. When this punching metal is attached to the speaker unit, metal parts, synthetic resin attachment members, and other parts such as a housing are mechanically connected.

  As an example of this case, a method of fixing a resin through a punching metal, a method of fixing using a screw, or the like is employed. However, when these mechanical connections are made, they can be fixed, but not completely fixed. Moreover, in a speaker unit that places importance on design, a resin body or a screw for mounting comes out on the surface, which is not preferable in appearance.

  Further, mechanical connection such as screws and fittings impedes the sound characteristics that are the life of the speaker. In other words, when the punching metal and the parts such as the casing are fastened together mechanically and partially with screws or the like, the sound is vibration transmission of a medium such as air or solid. Depending on the strength of the mechanical clamp, the sound output characteristics will change. As a result, the set sound output changes and adversely affects the sound quality.

  There are chimes, buzzers, bells, etc. in addition to the speakers that are applied to those that produce sound that are punched or have a net-like thin plate on the surface, but the present invention is limited to speakers Invention. The characteristic of the speaker is that it has a function of reproducing natural sound such as voice or sound into an electric signal to be reproduced as an original sound wave. Therefore, the speaker itself generates vibration, and mainly uses a diaphragm. Although there are various forms, the form of use is almost established by the field of use.

  Generally, a speaker is configured as a speaker unit, and is attached to an audio device, a television, an automobile, or the like in a built-in form. Various improvements have been made to improve the sound quality, but the structure that connects the speaker grill and the speaker unit also occupies a large factor. The quality of sound quality is based on various factors, and is determined by, for example, the following indicators.

  The frequency characteristics are required so that the pitch of the human audible range can be reproduced over the entire area. As for the distortion rate, the sound wave is similar to the waveform of the input signal, and output of a sound close to the original sound is required. There is also the pursuit of sound based on human preferences. With regard to directivity, it is required that the sound pressure is evenly distributed in all directions from the speaker, but it is also required to transmit a loud sound in a specific direction by narrowing the directivity.

  Thus, the speaker is required to have a clear sound with no noise. The improvement in sound greatly depends on the performance of the speaker itself, but the configuration of the speaker grill is also a major factor. The function of the speaker grill is to protect the speaker, and the material is made of metal or resin. A metal thing is a metal thin plate which has a hole or a net shape which is generally a through hole, and is characterized in that sound quality can be stably maintained. It is well known to apply this metal plate to a speaker grill (see, for example, Patent Documents 1 and 2).

  In general, a stainless steel plate or an aluminum alloy plate is used as the metal plate. The metal speaker grille can be reduced in thickness and is subjected to an etching process, and thus has high functionality such as strength improvement. In addition, it has quality because it is made of metal, such as surface smoothness, glossiness, metallic feeling, and high-quality feeling. A metal plate used as a speaker grille having a plurality of small holes is previously punched holes.

  The metal speaker grille is suitable for mass production at a low cost. The punched metal speaker grill itself is known. Factors that affect the sound quality of the speaker grill depend on the material, the number of holes provided in the speaker grill, and the shape of the hole. It becomes a big factor.

  In the conventional configuration, as described above, the metal speaker grille is fixed to an attachment body made of resin or the like by fixing means such as a screw. The structure in which the metal plate is directly fixed by the mechanical fixing means is avoided because the appearance is not good from the viewpoint of design and is often replaced with resin. For example, there exists an example attached to a door trim of a car as an interior part (for example, refer to patent documents 3 and 4).

  On the other hand, a technique for directly joining and integrating a resin body to a metal has been proposed by the present applicant and has already been implemented as a known technique (see, for example, Patent Document 5). Although the details are described in the patent literature, etc., it will be omitted, but this technology applies the surface of the metal to be joined to ultra-fine irregularities, injection-molds the thermoplastic resin composition, and firmly fixes the resin body to the metal It is something to be made. This metal-resin bonding technique has features such as weather resistance and water resistance, and is a technique that does not use an adhesive. In the present invention, this technique is referred to as NMT.

JP 2006-211732 A JP 2010-114806 A JP 2009-292438 A JP 2002-127833 A JP 2012-157991 A

  As described above, the metal plate speaker grille is unique because it is made of metal. However, there is a difficulty in the mounting structure of the speaker at present, and the metallic speaker grille is integrally fixed to a resin mounting body, unit, etc., and its acoustic characteristics are not improved or stabilized. Resin speaker grilles are made of resin, so there are restrictions on the shape of the hole shape, and there is a limit to how thin the speaker grille can be, making it unsatisfactory in design, such as being unable to give a sense of quality, and increasing strength. However, there are defects such as inferior to metal.

  For this reason, there has been a demand for a structure that improves the sound quality while integrating the metal plate with the resin body and having the original protection function as a speaker grille. Moreover, even if it is a metal plate, the increase in the number of parts which makes the speaker cost high, or a complicated fastening structure cannot be adopted at high cost. Therefore, there is a demand for a speaker grill having a configuration that can reduce the cost and can be mass-produced.

  The present invention has been invented based on the technical background as described above, and achieves the following objects. An object of the present invention is a speaker grill in which a punched metal plate is integrated with a resin mounting body by injection molding, and has a fixed structure that is surely and easily free from vibration. Another object of the present invention is to provide a speaker grill injection molded body that is fixed to the speaker unit via the mounting body so as to maintain high sound quality, and a molding method therefor.

The injection molding of the speaker grill of the present invention 1
A metal plate (2) in which a fine metal surface is processed by machining or chemical etching on a thin metal material that has been punched and processed into a predetermined shape;
It consists of the attachment body (3) of the thermoplastic resin composition integrated by injection molding with respect to the said fine uneven surface of the said metal plate (2).
The injection molded body of the speaker grill according to the present invention 2 is characterized in that, in the present invention 1, the material of the metal plate (2) is an aluminum alloy.

The speaker grill injection molding method of the present invention 3
A step of forming a metal plate (2) by subjecting a thin metal material that has been punched holes to a predetermined shape to surface treatment of fine irregularities;
Inserting the metal plate (2) having been subjected to the fine irregularities treatment into the mold (4);
A thermoplastic resin composition was injected into the cavity (5) in the shape of the mounting body (3) in the closed mold (4) to mold the mounting body (3), and the surface treatment of the fine unevenness was performed. And forming a speaker grill (1) integrated with the metal plate (2).

According to a fourth aspect of the present invention, there is provided an injection molding method for a speaker grille according to the third aspect, wherein the thermoplastic composition is injected into a punching hole (2a) of the metal plate (2). It is characterized by including a process.
The speaker grille injection molding method of the present invention 5 is the present invention 4,
The forming step of the attachment body is a step of injection molding that is limited to a portion immediately before the R portion of the punching hole of the metal plate.

  In the injection molding body and the molding method thereof for the speaker grill of the present invention, the metal speaker grill is formed by molding a resin attachment body on a metal plate by injection molding. For this reason, it became possible to attach to the counterpart member via the attachment body instead of the metal plate itself. The mounting body is integrated with the metal plate by molding. As a result, the attachment body itself is integrated with the metal plate by injection molding, and the attachment body, which is a resin body, can be bonded to the mating member by fixing or fusing. Therefore, even if the speaker grill is attached to a speaker or speaker unit, there is no risk of vibration with noise, and the speaker grill has a protective function and can be mass-produced at low cost without deteriorating sound quality. It became.

FIG. 1 is a partial cross-sectional view showing a mold for forming a speaker grill for injecting a metal plate including a punching hole and integrating a mounting body. FIG. 2 is a partial cross-sectional view showing a mold in a state where a speaker grill is formed including a mounting body in which resin is injected into the mold having the configuration shown in FIG. FIG. 3 is a diagram showing another embodiment, which has the same configuration as that shown in FIG. 1, and a speaker grill forming mold including a mounting body that is tangled and ejected with an end R portion of a punching hole. FIG. FIG. 4 is a view showing another embodiment, and is a partial cross-sectional view showing a mold in a speaker grill forming state having an attachment body injection-molded at the edge of a metal plate. FIG. 5 is a process diagram for forming a speaker grill in which a mounting body is integrated with a metal plate by injection molding.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are partial sectional views of a mold configuration for speaker grill injection molding showing an embodiment of the present invention. The actual shape of the speaker grille is complicated because the form of the speaker unit to be connected has various configurations. In order to facilitate understanding of the present embodiment, the shape of the speaker grill shown in the figure is a simple shape. FIG. 1 shows the state of the mold configuration before injection, and FIG. 2 shows the state after injection. The metal plate 2 constituting the main body of the speaker grill 1 is an aluminum alloy having a thickness of 1 mm in this example. In the embodiment, the metal plate 2 is made of an aluminum alloy, but it goes without saying that other metal plates may be used. The metal plate 2 is punched in advance.

  Since punching to a metal material is normally performed from one direction, the end (corner) 2b of the hole 2a on the punching side has an R shape, and the end 2c of the hole 2a on the opposite side from which punching comes off has burrs or the like. ing. In the case of the figure, the punching side is the surface that is exposed to the outside, and the opposite side is the back surface that faces the speaker side. By doing in this way, since the circumference | surroundings of the hole of the surface of the speaker grille 1 exposed outside are R shape, the whole surface comprises a smooth surface. Therefore, the opposite surface of the metal plate 2 is the attachment side, and the attachment body 3 is provided on this surface. With respect to the material of the metal plate 2 where the attachment body 3 is formed, the metal body 2 is obtained by subjecting the material of the metal plate 2 to surface treatment of ultra-fine irregularities. The shape of the attachment body 3 is a simple shape example in the present embodiment.

  The speaker grip 1 is fixed to the speaker or the speaker unit via the attachment body 3. Accordingly, the speaker grill 1 of the present example is configured to include the attachment body 3 on the metal plate 2. In order to avoid directly attaching the metal plate 2 to the speaker or the speaker unit as in the conventional case, the attachment body 3 is formed on the metal plate 2 by injection molding. By the injection molding, the attachment body 3 is firmly fixed to the metal plate 2, and the degree of freedom of the attachment configuration with respect to the speaker or the speaker unit is increased. The speaker grill 1 is formed by applying the NMT technology as described above. The configuration of the speaker grill 1 will be described with reference to the process diagram of FIG.

  First, the surface treatment of fine irregularities is performed on the material of the metal plate 2 that is punched to have a desired shape. This surface treatment method for fine irregularities is detailed in Japanese Patent Application Laid-Open No. 2003-200453, WO 2004-041532, and the aforementioned Patent Document 5 in the case of an aluminum alloy, and detailed description thereof is omitted. However, when large strength is not required for joining the metal plate and the resin, only general chemical etching treatment according to the type of metal, grinding with a grindstone, or unevenness of the surface of the material, The thing of the unprocessed process which does not perform this uneven | corrugated process may be used. The surface roughness of the surface treatment portion of the fine irregularities is that the average length (RSm) of the contour curve elements is 0.5 to 10 μm and the maximum height roughness (Rz) is 0.2 to 5 μm. good. In the case of this example, injection molding is performed in a form in which a part of the attachment body 3 is bitten into the punching hole. Next, the surface-treated metal plate 2 is inserted into a predetermined position of the mold 4, and the mold 4 in which the cavity 5 of the attachment body 3 that is a space portion is formed is closed.

  Next, a thermoplastic resin composition (hereinafter referred to as “resin”) is injected to form a resin attachment body 3, and a speaker grill 1 in which the attachment body 3 is integrated with the metal plate 2 is formed. In the case of the illustrated example, the attachment body 3 is configured to be provided in the intermediate portion of the metal plate 2. Therefore, a part of the attachment body 3 is configured to bite into the punching hole 2a. The mold 4 is normally provided with air vents as the injected resin is injected. In this example, however, the number of holes is particularly small and the air vents are provided for these holes. Not. However, the resin is configured to reach the R portion of the punching hole. If the resin reaches the outside through the punching hole, which is a through hole, a surface finishing process is required.

  The position of the attachment body 3 to the metal plate 2 and the shape of the attachment body 3 may be determined in accordance with the configuration of the counterpart speaker unit or the like. With such a configuration, it is possible to fix the speaker or the speaker unit by screwing, fitting, bonding, ultrasonic bonding, or the like via the attachment body 3. In particular, a resin speaker unit can be fused and fixed because it is made of resin with each other. Since the speaker grille 1 is partly integrated with the speaker unit when it is fusion-fixed, a problem that causes a reduction in sound quality is eliminated.

  Next, injection molding for the punching hole 2a will be described in detail. The example shown in FIG. 2 is an example in which the mounting body 3 is formed by setting an injection pressure within a range in which the resin does not reach the R portion of the hole 2a of the punched metal plate 2. In the case of this example, injection molding is performed without providing the mold 4 with air vents in the holes. Air pressure is generated in the resin upon injection, and the resin is compressed and injected. In the case of this example, the injection pressure is set so that the molding pressure reaches just before the R portion of the resin.

  By doing so, an air cushion is generated at the end of the hole 2a of the metal plate 2 and air does not escape, so that part of the air remains in the hole and a smooth dent S without resin is formed. Therefore, in the case of this example, a part of the attachment body 3 is not exposed to the outside of the surface beyond the hole. That is, after molding, there is no need for surface finishing, and the product can be commercialized as it is taken out from the mold, and the design is good.

(Other embodiment 1)
FIG. 3 shows a surface treatment of ultra-fine irregularities on both surfaces of a metal plate, that is, an etching process, and ends 6 on both sides of the punching hole 2a are formed into a round shape or a square chamfered shape by machining to form the mounting body 6. It is an example figure. In this case, the resin is injected by increasing the injection pressure so that the resin reaches the R portion. With this molding, the resin in the hole 2a extends to the end of the R portion. Since there is no air venting, the resin does not protrude beyond the R portion, and even after molding, the surface remains smooth and does not hinder the design. The attachment body 6 is firmly fixed in a state where the metal plate is sandwiched between the R portions of the resin on both sides.

(Other embodiment 2)
FIG. 4 is a partial view of the speaker grille 8 in which the attachment body 7 is formed on the edge 2d of the metal plate 2. As shown in FIG. In this case, the attachment body 7 is injection-molded so as to be provided on the entire periphery of the edge 2d of the metal plate 2. Therefore, the attachment body 7 in this case has a frame configuration. In the case of this example, even if the edge 2d of the metal plate 2 has a burr or the like, it is in a state of being covered with resin. Therefore, finishing treatment such as deburring of the edge 2d is not necessary.

  In addition, the edge 2d can be injection-molded with the shaped body 9 that is communicated and wrapped with the hole 2a on the edge 2d side. For this reason, the attachment body 7 is more firmly fixed to the metal plate 2. When this frame configuration is joined to the shape of the speaker unit and joined, the speaker grille 8 can be attached to the speaker without exposing the edge 2d of the metal plate 2.

  The metal plate has been described as a metal plate having punching holes as described above, but may be a net-like one. In the case of a net-like shape, there is a possibility of overhanging from the net portion when the resin is injection-molded. Moreover, although the shape of the attachment body was demonstrated as a simple shape, it cannot be overemphasized that it is not limited to this shape.

DESCRIPTION OF SYMBOLS 1, 8 ... Speaker grill 2 ... Metal plate 2a ... Punching holes 3, 6, 7 ... Mounting body 4 ... Mold 5 ... Cavity

Claims (5)

A metal plate (2) in which a fine metal surface is processed by machining or chemical etching on a thin metal material that has been punched and processed into a predetermined shape;
An injection molded body of a speaker grill, comprising: a thermoplastic resin composition mounting body (3) integrated with the fine uneven surface of the metal plate (2) by injection molding. In the injection molding of the speaker grill according to claim 1,
An injection-molded body for a speaker grill, wherein the metal plate (2) is made of an aluminum alloy. A step of forming a metal plate (2) by subjecting a thin metal material that has been punched holes to a predetermined shape to surface treatment of fine irregularities;
Inserting the metal plate (2) having been subjected to the fine irregularities treatment into the mold (4);
A thermoplastic resin composition was injected into the cavity (5) in the shape of the mounting body (3) in the closed mold (4) to mold the mounting body (3), and the surface treatment of the fine unevenness was performed. A speaker grill injection molding method comprising: forming a speaker grill (1) integrated with a metal plate (2). In the speaker grill injection molding method according to claim 3,
The method of injection molding a speaker grill, wherein the molding step of the attachment body (3) includes a step of injection molding the thermoplastic composition into a punching hole (2a) of the metal plate (2). The injection molding method for a speaker grill according to claim 4,
The forming step of the attachment body (3) is a step in which the thermoplastic composition is injection-molded while being limited to a portion immediately before the R portion of the punching hole (2a) of the metal plate (2). The speaker grill injection molding method.

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