JP2013198030A - Method for manufacturing diaphragm for loudspeaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain investments on die facility by improving a manufacturing yield of a laminate diaphragm for a loudspeaker.SOLUTION: A method for manufacturing a laminate diaphragm for a loudspeaker has: a molding step of molding a lower layer section 10B by hot-pressing a lower layer material 10A of a diaphragm impregnated with thermosetting synthetic resin with dies 32 and 34 of a thermal molding machine 30; a thermal welding layer formation step of coating a thermal welding sheet 12B on the lower layer section 10B; and a molding adhesion step of setting the lower layer section 10B molded and coated with the thermal welding sheet 12B and an upper layer material 16A of the diaphragm not molded in a thermal molding machine 50 and hot-pressing them, and adhering the upper layer section 16B and the lower layer section 10B by the thermal welding sheet 12B while making the upper layer material 16A into a shape of the upper layer section 16B of the diaphragm. While molding the upper layer material 10A into a shape of the upper layer section 16B, the lower layer section 10B is adhered to the upper layer section 16B. Therefore, there is no gap between the lower layer section 10B and the upper layer section 16B, and wrinkles on a surface of the diaphragm can be prevented.

Description

  The present invention relates to a method for manufacturing a speaker diaphragm.

  A speaker diaphragm is required to be lightweight and highly rigid. Some speaker diaphragms have a single-layer structure such as a single woven fabric, but such a single-layer structure cannot provide sufficient rigidity. Therefore, Patent Document 1 discloses a method for manufacturing a speaker diaphragm having a laminated structure. In the manufacturing method disclosed in Patent Document 1, the synthetic fiber sheets that are the lower layer and the upper layer of the diaphragm having a laminated structure are separately molded to perform the respective steps of manufacturing the lower layer molded product and the upper layer molded product. Then, the step of bonding the lower layer molded product and the upper layer molded product by sandwiching the thermal adhesive film is performed. As a result, a speaker diaphragm having a laminated structure having sufficient rigidity can be manufactured.

JP 2011-71707 A

  However, the above-described conventional method for manufacturing a speaker diaphragm includes a first mold for obtaining a lower-layer molded product, a second mold for obtaining an upper-layer molded product, a lower-layer molded product, and an upper-layer molded product. And a third mold for forming the two together. In order to overlap the upper layer molded product and the lower layer molded product without gaps, the upper layer molded product needs to have a shape offset by the thickness of the layer of the lower layer molded product. The shape of the second mold needs to be slightly different from the mold. Moreover, in order to perform the heat press normally by the 3rd metal mold | die, what superposed | stacked the lower layer molded product obtained by the 1st metal mold | die and the upper layer molded product obtained by the 2nd metal mold | die is 3rd. It is necessary to have a shape that can be molded by the mold. For this purpose, it is necessary to manufacture the first and second molds with high dimensional accuracy. For this reason, the conventional method for manufacturing a loudspeaker diaphragm having a laminated structure has a problem in that the equipment cost particularly for the mold increases. Further, depending on the shape of the diaphragm, it may be difficult to set the lower layer molded product and the upper layer molded product without any gaps and set the third mold. Then, when a gap is generated between the bonded lower layer molded product and the upper molded product, or the whole of the bonded lower molded product and upper molded product could not be set well in the third mold. In this case, there is a problem that a gap is formed inside the diaphragm after molding using the third mold, or wrinkles are generated on the surface, and the manufacturing yield of the diaphragm is lowered.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide technical means capable of improving the manufacturing yield of speaker diaphragms and reducing the cost of molds.

  The present invention includes a molding step of pressing the lower layer material of the diaphragm to form the shape of the diaphragm, a thermal welding layer forming step of coating the lower layer material molded by the molding step with a thermal welding sheet, and the thermal welding. The lower layer material coated with the sheet and the unmolded upper layer material are stacked so that the layer of the heat-welded sheet is between the upper layer material and the lower layer material, and then heat-pressed to form the upper layer material into the shape of the diaphragm. There is provided a method for manufacturing a loudspeaker diaphragm, comprising a molding and bonding step in which an upper layer material and a lower layer material are bonded to each other through a heat-welded sheet while being molded.

  According to this invention, in the molding and bonding step, the step of molding the upper layer material into the shape of the diaphragm and the step of bonding the upper layer material and the lower layer material are performed simultaneously. It is possible to prevent the molded shape from deviating and sticking together, and to prevent a gap from being formed between the upper layer material and the lower layer material and wrinkles from being generated on the surface of the diaphragm. In addition, since the mold used in the molding process and the mold used in the molding and bonding process can be the same mold, it is not necessary to prepare multiple molds. Can be suppressed.

It is a figure explaining each process in the manufacturing method of the diaphragm for speakers which is one embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
<Embodiment>
FIG. 1 is a diagram for explaining a method of manufacturing a speaker diaphragm according to an embodiment of the present invention. In the method for manufacturing the speaker diaphragm according to the present embodiment, the impregnation step, the molding step, the thermal welding layer step, and the molding and bonding step are sequentially performed. Hereinafter, each process is demonstrated in order.

(Impregnation process)
The impregnation step is a step of impregnating a woven fabric or the like that will be the lower layer material and upper layer material of the diaphragm with resin. As the woven fabric, for example, a woven fabric of synthetic fibers such as Zylon (registered trademark) (PBO (polyparaphenylene benzobisoxazole)) or Kevlar (registered trademark) (aramid fiber) is used. The resin impregnation by this impregnation step is performed in order to form the woven fabric into a diaphragm shape by hot pressing in the next forming step (or forming and bonding step). As the resin to be impregnated, various thermosetting synthetic resins such as a phenol resin, an epoxy resin, or a melamine resin can be used. FIG. 1A is a diagram illustrating an impregnation process. As shown in FIG. 1A, when the woven fabric 20 supplied from the roll 22 passes through the resin tank 26, the entire woven fabric is impregnated with the thermosetting synthetic resin 24. As a result, a woven fabric 20A impregnated with a thermosetting synthetic resin is obtained.

(Molding process)
The forming step is a step of forming the lower layer portion of the diaphragm by hot pressing the lower layer material of the diaphragm using a thermoforming machine. FIG. 1B is a diagram illustrating a molding process. The thermoforming machine 30 has molds 32 and 34. The molds 32 and 34 may be made in accordance with the shape of the lower layer portion of the completed diaphragm, but are made in accordance with the shape of the entire diaphragm that is the finished product. May be. When the molds 32 and 34 are formed in accordance with the shape of the entire diaphragm, the same mold as the mold used in the molding and bonding step described later may be used as the molds 32 and 34.

  In the molding process, the molds 32 and 34 are warmed to a temperature at which the thermosetting synthetic resin 24 used in the impregnation process can be cured. In the molding step, the woven fabric 20A impregnated with the thermosetting synthetic resin in the previous impregnation step is set between the molds 32 and 34 of the thermoforming machine 30 as the lower layer material 10A of the diaphragm. Next, the set lower layer material 10 </ b> A is hot-pressed by the molds 32 and 34. Thereby, the thermosetting synthetic resin in lower layer material 10A hardens | cures, 10A of lower layer materials are shape | molded by the diaphragm shape, and the lower layer part 10B of a diaphragm is obtained.

  In the molding step, hot press molding is not essential, and press molding may be simply performed as long as the lower layer material can be molded into a diaphragm shape. In the case of simply press molding, impregnation with a thermosetting synthetic resin is not essential.

(Thermal welding layer process)
The heat welding layer step is a step of coating the heat welding sheet on the lower layer portion 10B of the diaphragm formed in the previous molding step. FIG. 1C is a diagram for explaining the heat welding layer process. In the heat welding layer process, the heat welding device 40 is used. The heat welding apparatus 40 includes a mold 42 having a shape similar to that of the lower layer portion 10B. The heat welding apparatus 40 has a nozzle 44 below the mold 42 and a heater 46 above the mold 42.

  In the heat welding layer step, as shown in FIG. 1C, first, the lower layer part 10B is set on the mold 42 of the heat welding device 40, and the heat welding sheet 12 is set on the lower layer part 10B. Then, the heat welding sheet 12 is warmed from above by the heater 46 to soften the heat welding sheet 12, and the nozzle 44 is vacuum sucked toward the mold 42. Here, since the lower layer part 10B has air permeability, the heat welding sheet 12 does not have air permeability, and therefore the heat welding sheet 12 is attracted toward the mold 42 through the lower layer part 10B. As a result, the heat welding sheet 12 adheres to the lower layer part 10B. FIG. 1 (C) shows a heat-welded sheet 12B that is in close contact with the lower layer portion 10B. In this way, the lower layer part 14 (thermal welding sheet 12B + lower layer material 10B) in which the lower layer part 10B is uniformly coated with the heat welding sheet 12B is generated.

(Molding and bonding process)
The forming and bonding step is a step of bonding the lower layer portion 14 coated with the heat welding sheet while forming an unformed upper layer material. FIG. 1D is a diagram for explaining the molding and bonding step. In the molding and bonding step, a thermoforming machine 50 is used. The thermoforming machine 50 has molds 52 and 54. The molds 52 and 54 are made in accordance with the shape of the diaphragm which is a finished product.

  In the molding and bonding step, the molds 52 and 54 are warmed to a temperature at which the thermosetting synthetic resin 24 used in the impregnation step can be cured and the thermal welding sheet 12B can be softened. Then, in the molding and bonding step, as shown in FIG. 1D, the lower layer portion 14 is formed on the thermoforming machine 50 so that the surface coated with the heat welding sheet 12B becomes the upper surface (the surface not in contact with the mold 52). Set on the mold 52. Thereafter, the upper layer material 16 </ b> A of the diaphragm impregnated with the thermosetting synthetic resin 24 is set on the lower layer part 14 set in the mold 52. That is, it arrange | positions so that a heat welding sheet may be between lower layer material and upper layer material. Next, the set lower layer portion 14 and upper layer material 16A are hot-pressed by the molds 52 and 54.

  Here, since the upper layer material 16A is impregnated with a thermosetting synthetic resin, the upper layer material 16A is hardened by heat while being formed into a diaphragm shape by hot pressing to become the upper layer portion 16B. At the same time, the heat welding sheet 12B between the upper layer portion 16B and the lower layer portion 14 is melted by hot pressing, and the upper layer portion 16B and the lower layer portion 14 are bonded by the melted heat welding sheet 12B. Thereby, the diaphragm 18 of the laminated structure by which the lower layer part 10B and the upper layer part 16B were bonded together via the heat welding sheet | seat 12B is obtained.

  In the molding and bonding step, the upper layer material may not be impregnated with the thermosetting synthetic resin as long as the upper layer material can be molded and bonded.

  As described above, according to the present embodiment, in the molding and bonding step, the upper layer material is molded into the shape of the diaphragm, and the lower layer material and the upper layer material are bonded at the same time. The diaphragm can be manufactured without generating a gap between the lower layer portion and the surface of the diaphragm without generating wrinkles.

  In the present embodiment, the molding of the upper layer material and the bonding of the lower layer material and the upper layer material are performed at the same time in the molding and bonding step, so that a mold for separately molding only the upper layer material is not required. Further, the same mold can be used as the mold in the molding process and the mold in the molding and bonding process. Conventional manufacturing methods require three types of molds: a mold for molding the lower layer material, a mold for molding the upper layer material, and a mold for bonding the lower layer molded product and the upper layer molded product. However, in this embodiment, by using the same mold in the molding process and the molding and bonding process, it is sufficient to prepare at least one type of mold that has the product dimensions of the diaphragm. Thereby, the capital investment for preparing a metal mold | die can be suppressed.

  In addition, in the conventional manufacturing method, it is necessary to perform three times of heat pressing, that is, a step of forming the lower layer material, a step of forming the upper layer material, and a step of bonding the lower layer formed product and the upper layer formed product. The hot pressing may be performed twice in a molding process for molding the lower layer material and a molding and bonding process. For this reason, manufacturing cost can be reduced by simplification of a process.

  Moreover, in this embodiment, since the heat welding sheet is used for adhesion | attachment with the lower layer part 10B and the upper layer part 16B, the lower layer part 10B and the upper layer part 16B can be adhere | attached uniformly. If the lower layer portion 10B and the upper layer portion 16B are bonded with an adhesive, unevenness may occur in adhesion due to uneven application of the adhesive. However, in this embodiment, since the heat-welded sheet is vacuum-sucked in the heat-welding layer forming step, the heat-welding sheet can be uniformly adhered to the lower layer material, and in the molding and bonding step, the lower layer portion 10B and the upper layer portion 16B. Can be adhered uniformly without unevenness.

  The manufacturing method according to the present embodiment can be applied to various types of diaphragms such as a cone type, a dome type, and a flat type, for example. Among the various types of diaphragms, in particular, a trumpet shape is formed as shown in FIG. This is effective in improving the manufacturing yield when manufacturing a diaphragm in which the curvature of the vibration surface changes from the portion toward the outer peripheral end. In the conventional manufacturing method, it is difficult to bond the lower layer molded product and the upper layer molded product and set them in the mold, so that the manufacturing yield of the diaphragm may be lowered. However, according to the manufacturing method according to the present embodiment, when the diaphragm having such a shape is manufactured, generation of a gap between the lower layer portion and the upper layer portion of the diaphragm and generation of wrinkles on the surface of the diaphragm are prevented. And the manufacturing yield of the diaphragm can be improved.

<Other embodiments>
Although one embodiment of the present invention has been described above, other embodiments are conceivable for the present invention. For example:

  (1) In one embodiment, the lower layer material and the upper layer material are woven fabrics. However, the lower layer material and the upper layer material are not limited to the woven fabric, and the lower layer material and the upper layer material may be different materials. For example, paper may be used for the lower layer material and PBO woven fabric may be used for the upper layer material.

  (2) When a woven fabric is used as the lower layer material and the upper layer material, in the molding and bonding step, the upper layer material has a 45-degree angle with respect to the lower layer material, and heat welding is performed. The upper layer material may be placed on the lower layer portion coated with the sheet, and hot pressing may be performed. In this case, since the diaphragm in which the texture direction of the upper layer part and the texture direction of the lower layer part form an angle of 45 degrees is obtained, the effect that the rigidity anisotropy of the diaphragm can be suppressed is obtained.

DESCRIPTION OF SYMBOLS 10,10A ... lower layer material, 10B ... lower layer part, 12, 12B ... heat welding sheet, 14 ... lower layer material coated with heat welding sheet, 16A ... upper layer material, 16B ... upper layer part, 18 ... diaphragm, 20, 20A ... Woven cloth, 22 ... Roll, 24 ... Thermosetting synthetic resin, 26 ... Resin tank, 30, 50 ... Thermoforming machine, 32, 34, 42, 52, 54 ... Mold, 40 ... Thermal welding apparatus, 44 ... Nozzle, 46 ... heater.

Claims (5)

A molding step of pressing the lower layer material of the diaphragm into a diaphragm shape;
A heat-welding layer forming step of coating a heat-welding sheet on the lower layer material formed by the forming step;
The lower layer material coated with the heat welding sheet and the unmolded upper layer material are stacked so that the layer of the heat welding sheet is between the upper layer material and the lower layer material, and the upper layer material is vibrated by hot pressing. A method of manufacturing a speaker diaphragm, comprising: a molding and bonding step in which an upper layer material and a lower layer material are bonded to each other through a heat welding sheet while being molded into a plate shape.   2. The speaker diaphragm manufacturing method according to claim 1, wherein in the molding step, the lower layer material impregnated with the thermosetting resin is hot-pressed to be molded into a diaphragm shape.   The method for manufacturing a speaker diaphragm according to claim 2, wherein pressing is performed using the same mold in the molding step and the molding and bonding step.   The method for manufacturing a speaker diaphragm according to any one of claims 1 to 3, wherein a woven fabric or paper is used for the upper layer material and the lower layer material. Using a woven fabric for the upper layer material and the lower layer material,
In the molding and bonding step, the lower layer material coated with the heat welding sheet and the upper layer material that is not molded are overlapped so that the texture direction of the lower layer material and the texture direction of the upper layer material form an angle of 45 degrees. The method for manufacturing a speaker diaphragm according to any one of claims 1 to 3.

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