JP2011071707A - Diaphragm for speaker, and method of manufacturing diaphragm for speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm for speaker having high rigidity, lightweight and a moderate internal loss, and to provide a method of manufacturing the same. <P>SOLUTION: A first molding 16A and a second molding 16B are formed by impregnating resin for improving adhesion into poly-p-phenylene benzobisoxazole (PBO) woven cloth 116 obtained by using the PBO being a synthetic fiber having a very high elastic modulus and a moderate internal loss for warpage and weft and weaving the PBO in the shape of a lattice and molding the PBO woven cloth into a shape corresponding to a speaker unit 1 by a hot pressing device. A diaphragm 16 of a three-layer structure is generated by inserting a thermal adhesive film 16C between the first molding 16A and the second molding 16B, overlapping them such that threads of the first molding 16A and the second molding 16B are turned to different directions and performing hot pressing of the first molding 16A and the second molding 16B by the hot pressing device 105. Further, unneeded parts of the diaphragm 16 are cut, and the surface of the diaphragm 16 is coated with gold by means of sputtering in order to prevent the PBO woven cloth 116 from being deteriorated. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a speaker diaphragm having a light weight, high rigidity, and appropriate internal loss, and a method for manufacturing the speaker diaphragm.

  A speaker diaphragm is required to be lightweight, have high rigidity, and have an appropriate internal loss.

  Conventionally, a para-aramid fiber (for example, Kevlar (registered trademark)) woven fabric, which is a synthetic fiber having a high elastic modulus, is used for a speaker diaphragm so as to satisfy the above conditions (see Patent Document 1). .

British Patent No. 1491080

  However, the conventional diaphragm for a speaker has a problem that even if a synthetic fiber having a high elastic modulus as described above is used, sufficient rigidity cannot be obtained because the woven fabric is a single layer.

  Accordingly, an object of the present invention is to provide a speaker diaphragm having a light weight, high rigidity, and appropriate internal loss, and a manufacturing method thereof.

  The present invention has the following configuration as means for solving the above problems.

  The speaker diaphragm according to the present invention is obtained by impregnating a synthetic fiber sheet made of a woven fabric woven with synthetic fibers with a resin and sandwiching a thermal adhesive film between the plurality of synthetic fiber sheets, thereby weaving the woven fabric. Are laminated differently, and each synthetic fiber sheet is bonded with a heat adhesive film to form a laminated structure.

  By stacking a plurality of synthetic fiber sheets into a laminated structure, the rigidity can be made higher than that of a single-layer synthetic fiber sheet. In addition, the synthetic fiber sheet can be made lighter if the synthetic fiber sheet alone is thicker than the synthetic fiber sheet alone. Furthermore, since the synthetic fiber sheets have the same fiber direction, the synthetic fiber sheets can be deflected so that the directions of the fibers are different, thereby canceling the deflection of the synthetic fiber sheet. Therefore, it is possible to provide a speaker diaphragm that is more rigid and lighter than conventional ones and has no deflection. Further, by selecting a synthetic fiber having an appropriate internal loss, it is possible to suppress the resonance peak and flatten the reproduction frequency characteristic.

  In the above configuration, the surface of the synthetic fiber sheet having a laminated structure is coated with gold by sputtering. The surface of the speaker diaphragm can be prevented from being deteriorated by coating with gold. In addition, the gold coating prevents the synthetic fibers from being exposed to light and moisture, so that the synthetic fibers are less likely to deteriorate and the durability can be improved. Further, since sputtering can make the film thinner and more uniform than plating or the like, an increase in the weight of the speaker diaphragm can be kept to a minimum.

  In the above configuration, the synthetic fiber sheet is made of a woven fabric woven only with polyparaphenylene benzobisoxazole. Polyparaphenylene benzobisoxazole has the highest level of rigidity and elastic modulus among organic synthetic fibers. For example, it has a tensile elastic modulus about twice that of para-aramid fibers. Therefore, by making the speaker diaphragm with a woven fabric using this fiber, the rigidity can be made higher than before. Also, since polyparaphenylene benzobisoxazole has a moderate internal loss, creating a diaphragm with this material can suppress the resonance peak and flatten the reproduction frequency characteristics. It is possible to provide a speaker diaphragm with good quality.

  The method for manufacturing a speaker diaphragm of the present invention includes an impregnation step, a molding step, a lamination step, and an adhesion step. In the impregnation step, the synthetic fiber sheet is impregnated with resin. In the molding process, a synthetic fiber sheet impregnated with resin is press-molded into a diaphragm shape. In the laminating step, a heat-adhesive film is sandwiched between a plurality of molded synthetic fiber sheets, and the woven fabrics are stacked so as to have different weaving directions to form a laminated structure. In the bonding step, a plurality of diaphragm-shaped molded products having a laminated structure are bonded. By stacking a plurality of synthetic fiber sheets into a laminated structure, the rigidity can be made higher than that of a single-layer synthetic fiber sheet. In addition, the synthetic fiber sheet can be made lighter if the synthetic fiber sheet alone is thicker than the synthetic fiber sheet alone. Furthermore, since the synthetic fiber sheets have the same fiber direction, the synthetic fiber sheets can be deflected so that the directions of the fibers are different, thereby canceling the deflection of the synthetic fiber sheet. Therefore, by laminating a plurality of synthetic fiber moldings in this way, a speaker diaphragm that is lightweight and highly rigid can be manufactured. In the bonding step, a plurality of synthetic fiber moldings are bonded with a heat-adhesive film. By using a heat-adhesive film for bonding a plurality of synthetic fiber moldings, the entire synthetic fiber molding is brought into uniform contact with each other, and the whole is uniformly bonded. Since the heat-adhesive film also has a certain thickness, the rigidity of the diaphragm can be further improved. Furthermore, since the entire synthetic fiber molding is bonded with a non-breathable heat-adhesive film, the diaphragm can be processed so as not to vent without additional sealing.

  The above configuration further includes a sputtering step. In the sputtering process, the surface of the synthetic fiber sheet having a laminated structure is coated with gold by sputtering. By sputtering gold on the surface of the synthetic fiber sheet, deterioration due to light and moisture can be prevented and durability can be improved while minimizing an increase in weight.

  According to the present invention, it is possible to provide a speaker diaphragm having a light weight, high rigidity, and appropriate internal loss, and a method for manufacturing the speaker diaphragm.

(A) is a front perspective view of a dome type speaker device provided with the speaker diaphragm according to the embodiment of the present invention, and (B) is a front view of the speaker diaphragm (diaphragm unit). (A)-(C) is a figure showing a manufacturing process of a diaphragm for speakers concerning an embodiment of the present invention. It is a figure which shows the state at the time of manufacture of the diaphragm for speakers.

  Hereinafter, a case where the speaker diaphragm according to the embodiment of the present invention is applied to a dome-shaped speaker will be described as an example.

  As shown in FIG. 1A, the speaker unit 1 is a dome-type speaker, and includes a yoke 11A, a yoke 11B, a magnet 12, a plate 13, a frame 19, a packing 20, and a diaphragm unit 21. The diaphragm unit 21 includes a bobbin 14, a voice coil 15, a diaphragm 16, and a roll edge 17.

  The yoke 11 </ b> A, the yoke 11 </ b> B, the magnet 12, and the plate 13 constitute a magnetic circuit 10. In the magnetic circuit 10, a voice coil 15 is inserted into a magnetic gap S provided between the outer peripheral portion of the plate 13 and the inner peripheral portion of the yoke 11B. The voice coil 15 is wound around a bobbin 14, and the end of the bobbin 14 is connected to a boundary portion between the diaphragm 16 and the roll edge 17.

  The diaphragm 16 is formed in a dome shape, and a roll edge 17 is connected to the outer peripheral portion. The diaphragm 16 vibrates according to a sound signal input from the outside, and generates a sound wave. The diaphragm 16 is a three-layer laminated structure in which a molded product of two front and back surfaces obtained by molding a synthetic fiber woven fabric impregnated with a resin into a dome shape is bonded with a heat adhesive film, and the surface is coated with gold. For the two woven fabrics, polyparaphenylene benzobisoxazole (hereinafter referred to as PBO) is used as an example of an organic synthetic fiber. PBO is generally known under the trade name of Zylon (registered trademark). PBO has the highest tensile elastic modulus among organic synthetic fibers, and is about twice that of para-aramid fibers. PBO has a moderate internal loss. The PBO woven fabric 116 is woven only with PBO fibers, and as shown in FIG. 1B, warp yarns and weft yarns in which the directions of the fibers are aligned are woven in a lattice shape.

  The roll edge 17 is formed along the outer peripheral portion of the diaphragm 16 and includes a concave portion 17A having an arcuate cross section and a holding portion 17B having a flat cross section. The inner periphery of the recess 17A is connected to the diaphragm 16, and a holding portion 17B is provided on the outer periphery of the recess 17A. The holding portion 17B is supported in a state of being sandwiched between an annular packing 20 disposed on the upper portion of the yoke 11B and the frame 19.

  The frame 19 is installed to face the outer peripheral portion of the diaphragm 16.

  Since the diaphragm unit 21 includes the bobbin 14, the voice coil 15, the diaphragm 16, and the roll edge 17 integrally, it can be easily attached and replaced.

  Next, a method for manufacturing the diaphragm 16 will be described with reference to FIG.

(1) Impregnation step As shown in FIG. 2A, when the PBO woven fabric (synthetic fiber sheet) 116 supplied from the roll 101 passes through the resin tank 102A of the resin impregnation apparatus 102, the entire PBO woven fabric 116 is obtained. Impregnated with resin. The PBO woven fabric 116 impregnated with the resin is referred to as a PBO woven fabric 116A. The resin impregnation is performed in order to form the PBO woven fabric 116 into a diaphragm shape by hot pressing in the next molding step.

  As the resin impregnated into the PBO woven fabric 116, any resin can be used. For example, a thermosetting synthetic resin material such as a phenol resin, an epoxy resin, or a melamine resin is used.

  In addition, the thickness and surface density of the PBO woven fabric 116 used for the diaphragm may be selected according to conditions such as a speaker size and a sound range. In the case of a loudspeaker, it is desirable to be as light as possible, so a fairly thin PBO woven fabric such as 0.2 mm is used. In addition, in the case of a low-frequency speaker, a certain amount of weight is required. For example, a thick PBO woven fabric of about 1 mm is used.

(2) Molding process As shown in FIG. 2 (B), the PBO woven fabric 116A is hot press-molded into a dome shape by using the mold 103A and the mold 103B of the hot press apparatus 103 to produce the first molded product 16A. To do. Further, the PBO woven fabric 116A is hot-press molded into a dome shape by the mold 104A and the mold 104B of the hot press device 104, and the second molded product 16B is created.

  In the molding process, hot press molding is not essential, and press molding may be simply performed as long as the first molded product 16A and the second molded product 16B can be molded into a dome shape.

(3) Laminating step and bonding step In the two steps, the first molded product 16A and the second molded product 16B after molding the PBO woven fabric 116A impregnated with resin are stacked with the heat adhesive film 16C sandwiched therebetween. The first molded product 16A and the second molded product 16B are bonded to each other with a heat adhesive film 16C to form a laminated structure.

  First, the thermoadhesive film 16C is placed on the back surface (concave side) of the first molded product 16A, and vacuum suction is performed from the surface (convex portion side) of the first molded product 16A. The first molded product 16A is made of a PBO woven fabric 116A and has air permeability, and since the heat-adhesive film does not have air permeability, the heat-adhesive film 16C is brought into close contact with the first molded product 16A by vacuum suction. be able to. This step is performed before the bonding step shown in FIG. In FIG. 2C, the thermal adhesive film 16C is indicated by a dotted line in order to distinguish the first molded product 16A from the thermal adhesive film 16C.

  Subsequently, as shown in FIG. 2C, the first molded product 16A and the second molded product 16B to which the heat-adhesive film 16C is adhered are hot-pressed into a dome shape by the hot press device 105, and three layers are formed. A diaphragm (stacked diaphragm) 16D having a structure is generated. In the figure, the first molded product 16A is the front side of the diaphragm 16D.

  Since the PBO woven fabric 116 is impregnated with the resin, the PBO woven fabrics 116 can be easily bonded to each other by the heat adhesive film 16C.

  It is possible to apply an adhesive to the first molded product 16A or the second molded product 16B and bond them together, but the entire dome can be obtained by using the heat-adhesive film 16C and vacuuming as described above. The heat-adhesive film 16C can be brought into contact without any unevenness. Therefore, the entire dome of the first molded product 16A and the second molded product 16B can be bonded uniformly. Further, since the entire dome of the synthetic fiber sheet is bonded with a heat-adhesive film having no air permeability, the diaphragm 16 can be processed so as not to vent, and there is no need to perform a separate sealing process.

  Rather than making the synthetic fiber sheet alone thick, it can be made lighter if a plurality of synthetic fiber sheets bonded together have the same rigidity. Therefore, a speaker diaphragm that is lightweight and has high rigidity can be manufactured by stacking a plurality of synthetic fiber moldings in this manner.

  Since the bobbin 14 is attached to the diaphragm 16 as described above, it is preferable that the outer peripheral portion of the diaphragm 16 is flat and has no deflection. When the first molded product 16A and the second molded product 16B are molded from the PBO woven fabric 116A, a slight deflection occurs in both molded products. However, if the weaving directions of the yarns (fibers) of the woven fabric used for both molded products are overlapped, the deflections of the first molded product 16A and the second molded product 16B cancel each other. Can be reduced. As shown in FIG. 3, the deflection can be reduced most by superimposing the yarns (warp yarns or weft yarns) of the PBO woven fabric 116A so that the weaving directions are shifted by 45 degrees.

  In addition, in the molding process, by cutting the first molded product 16A and the second molded product 16B into a rectangular shape including the unnecessary portion, as shown in FIG. As a guide, the yarn direction of the PBO woven fabric 116A can be easily changed to different directions.

  Note that the thickness of the heat-adhesive film is also determined according to the thickness of the synthetic fiber sheet depending on conditions such as the size of the speaker and the sound range.

(4) Cut process The unnecessary part of the outer peripheral part of diaphragm 16D is press-cut with metal mold 106A and metal mold 106B of cutting device 106, and diaphragm 16E is created.

(5) Sputtering Step A diaphragm 16E is set between the target 107A of the sputtering apparatus 107 and the sample stage 107B, and gold is coated on the surface 16H of the diaphragm 16E by sputtering. The thickness of the gold film is, for example, about 0.2 μm. If gold is coated on the surface 16H of the diaphragm 16E, the PBO woven fabric 116A is not exposed to light (for example, ultraviolet rays) or moisture, so that the PBO woven fabric 116A is less likely to deteriorate and durability can be improved. Since gold is very difficult to oxidize, it is possible to maintain a high-grade feeling without coating the surface 16H of the diaphragm 16E by coating gold. Further, since sputtering can make the film thinner than plating or the like, an increase in the weight of the diaphragm 16E can be minimized. The roll edge 17 created in a separate process is attached around the diaphragm 16 created as described above with an adhesive or the like, and the voice coil 15 is wound around the boundary between the diaphragm 16 and the roll edge 17. The bobbin 14 is bonded to create the diaphragm unit 21. When the annular packing 20 is disposed on the upper part of the yoke 11B of the speaker unit 1 assembled in a separate process and the holding portion 17B of the roll edge 17 is attached so as to be sandwiched between the packing 20 and the frame 19, the speaker unit 1 Is the completion.

  As described above, the diaphragm 16 is manufactured by superimposing two molded products obtained by molding the PBO woven fabric 116, which is a synthetic fiber, into a shape corresponding to a speaker so that the yarns (fibers) face different directions. It is possible to provide a diaphragm having high rigidity and light weight. Further, by coating the surface of the diaphragm 16 with gold by sputtering, the deterioration of the PBO woven fabric 116 can be prevented. Further, since PBO has an appropriate internal loss, the diaphragm 16 is made of the PBO woven fabric 116, so that the resonance peak can be suppressed and the reproduction frequency characteristic can be flattened.

  In the above description, the case where xylon is used as an example of the synthetic fiber has been described. However, the present invention is not limited to this, and another synthetic fiber may be used. For example, highly elastic synthetic fibers such as para-aramid fibers (Kevlar (registered trademark)), polyethylene, and PAN-based carbon are applicable.

  The diaphragm according to the embodiment of the present invention is not applied only to the dome type speaker, but can be applied to all speakers using the diaphragm such as a cone type speaker and a flat type speaker.

  In the above description, an example of manufacturing a speaker diaphragm by laminating two woven fabrics (fiber sheets) made of synthetic fibers has been described, but the present invention is not limited to this, and a plurality of woven fabrics It is naturally possible to perform hot press molding by sandwiching a heat-adhesive film between fabrics (fiber sheets). In this case, a vibration-free diaphragm can be manufactured by stacking a plurality of woven fabrics (fiber sheets) so that the weaving directions of the fibers are different.

DESCRIPTION OF SYMBOLS 1 ... Speaker unit 10 ... Magnetic circuit 11A, 11B ... Yoke 12 ... Magnet 13 ... Plate 14 ... Bobbin 15 ... Voice coil 16 ... Diaphragm 16A ... 1st molded product 16B ... 2nd molded product 16C ... Thermal adhesive film 17 ... Roll edge 19 ... Frame 20 ... Packing 21 ... Diaphragm unit 101 ... Roll 102 ... Resin impregnation device 103 ... Hot press device 104 ... Hot press device 105 ... Hot press device 106 ... Cutting device 107 ... Sputtering device 116, 116A ... PBO weave cloth

Claims (5)

A plurality of synthetic fiber sheets made of a woven fabric made of synthetic fibers and impregnated with a resin are stacked so that the weaving directions of the woven fabrics are different by sandwiching a thermal adhesive film between them, and the respective synthetic fiber sheets are bonded. A loudspeaker diaphragm characterized by having a laminated structure.   The speaker diaphragm according to claim 1, wherein the surface of the synthetic fiber sheet having the laminated structure is coated with gold by sputtering.   The speaker diaphragm according to claim 1, wherein the synthetic fiber sheet is made of a woven fabric woven only with polyparaphenylene benzobisoxazole. An impregnation step of impregnating a synthetic fiber sheet made of a woven fabric woven with synthetic fibers with a resin;
A molding step of molding the impregnated synthetic fiber sheet into the shape of a diaphragm;
After molding, a laminating step in which a thermal adhesive film is sandwiched between the plurality of synthetic fiber sheets, and the woven fabrics are stacked so that the weaving directions thereof are different from each other to form a laminated structure;
Adhering step of creating a laminated diaphragm by adhering the synthetic fiber sheet having the laminated structure;
A method for manufacturing a speaker diaphragm comprising:   The method for manufacturing a speaker diaphragm according to claim 4, further comprising: a sputtering step of coating the surface of the synthetic fiber sheet having the laminated structure with gold by sputtering.

Images