JP4604180B2 - Speaker diaphragm and manufacturing method thereof - Google Patents

Description

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

  The speaker diaphragm has been selected for its material and manufacturing method so that various characteristics can be obtained according to the target reproduction band. However, because the opportunities for using the speaker in various environments have increased, Corresponding environmental resistance is regarded as important as the performance of the speaker diaphragm.

  In particular, in recent years, an opportunity to use a speaker for in-vehicle use has increased, and a performance that can withstand use in a vehicle is required. In a car, a speaker is generally installed at a door, and the on-vehicle speaker diaphragm is required to have durability against rain and car water and detergent.

  On the other hand, as a diaphragm for a speaker having waterproofness, an injection molded thermoplastic resin such as polypropylene has been used for a long time. However, such a resin injection molded diaphragm can provide high waterproof properties, but has a problem in weight reduction, and is limited to physical properties required for the diaphragm such as high Young's modulus and appropriate internal loss. For example, even if the density is set arbitrarily, there is almost no degree of freedom in the adjustment, and it is not satisfactory in designing various characteristics of the speaker diaphragm.

  On the other hand, the speaker diaphragm formed by fiber making (paper making) can be selected from natural fibers, chemical fibers, inorganic fibers, etc. depending on the purpose, and the density can be easily adjusted. The advantage is that various physical properties such as Young's modulus and internal loss can be adjusted to some extent. However, the bond between fibers is mainly based on hydrogen bonds, and since there is a gap between the fibers, it has a disadvantage of being vulnerable to water.

  Various proposals have been made to provide waterproofness to such a papermaking speaker diaphragm. For example, in the one described in Patent Document 1 below, a diaphragm made of a fiber material mainly composed of natural fibers is impregnated with a thermoplastic resin mixed with a release agent such as silicone oil, and then subjected to pressure heat treatment. Has been proposed.

JP 60-30299 A

  As in the prior art described above, in the speaker diaphragm made of fiber, the paper making base material is impregnated with various resins for waterproofing. However, it is not possible to prevent the entry of an aqueous solution containing a surfactant (for example, a detergent solution for car washing). In addition, if the amount of resin adhesion (impregnation amount) is increased in order to further improve the waterproof property, the weight reduction characteristic of the diaphragm made by papermaking is lost as a result, and it is close to a resin molded product in terms of weight. There was a problem of becoming something.

  This invention makes it an example of a subject to cope with such a problem. That is, it is possible to obtain a speaker diaphragm having excellent waterproofness, particularly durability against an aqueous solution containing a surfactant, while making full use of the advantages of the speaker diaphragm made of fibers. Is the purpose.

  In order to achieve such an object, a speaker diaphragm and a method for manufacturing the same according to the present invention include at least the configurations according to the following independent claims.

[Claim 1]
A speaker diaphragm having at least three layers formed by sucking a papermaking material mixed with a fiber base material and a heat-expandable component , the surface of the speaker diaphragm on the non-suction side mainly A first layer formed of a fiber base material and the back surface portion on the suction side of the speaker diaphragm, which densely includes the heating expansion component expanded by heating and seals a gap between the fiber base materials. a third layer was located between the first layer and the third layer, speaker, characterized in that it comprises a second layer that contains the heating expansion component sparsely in the fiber substrate Diaphragm.

[Claim 4 ]
A method for manufacturing a diaphragm for a speaker , comprising a step of slurrying water, a plurality of fiber materials, and heat-expandable unexpanded particles having a specific gravity higher than water, and a paper placed on a mold having a predetermined shape A step of sucking the slurry through a net to form a paper base comprising the fiber base material composed of the plurality of fiber materials and the unexpanded particles non-uniformly on the paper net, and heating and pressurizing the papermaking body. And expanding the unexpanded particles, and a first layer mainly formed of the fiber base material on a surface portion on the non-suction side of the speaker diaphragm, and the heating expanded by heating Between the first layer and the third layer formed between the first layer and the third layer, which is formed on the back surface portion on the suction side of the speaker diaphragm, which densely contains an expansion component and seals the gap between the fiber base materials Located and sparsely contains the thermal expansion component in the fiber substrate Method for manufacturing a speaker diaphragm, characterized by producing a speaker diaphragm comprising a second layer, the that.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a loudspeaker diaphragm according to an embodiment of the present invention (FIGS. 1B and 1C are enlarged views of portion A of FIG. 1A). Here, a cone type diaphragm is shown, but the form of the diaphragm is not limited to this, and various forms such as a dome shape and a planar type may be used.

  The diaphragm 1 according to the embodiment of the present invention includes a fiber base material 1A. In the first embodiment, as shown in FIG. 1B, at least one surface layer of the fiber base material 1A is used as a gap sealing layer 1a. Yes. In the illustrated example, the gap sealing layer 1a is formed on the back side of the diaphragm 1. However, the present invention is not limited to this, and the same gap sealing layer 1a may be formed on the main surface side. You may form this space | gap sealing layer 1a in both the back side.

  The void sealing layer 1a is a layer in which voids formed between the fibers 1b in the fiber base 1A are filled. As an example, the voids between the fibers 1b are filled with a heat expansion component (foamed particles or the like) 1c. It is formed by.

  According to the diaphragm 1 according to this embodiment, since there is a gap between the fibers 1b except for the surface layer of the fiber base material 1A, the weight can be reduced in the same manner as the diaphragm of the conventional papermaking base material, and it is formed on the surface layer. Further, since the moisture entering the inside can be blocked by the air gap sealing layer 1a, sufficient waterproofness can be obtained.

  This waterproofness will be described in comparison with a conventional papermaking substrate impregnated with a waterproof resin. In the case of the prior art, although the resin is impregnated inside the substrate, Since the space between the fibers is not sufficiently filled, water enters the inside from the space. When the aqueous solution containing the surfactant enters the inside, the water breakability of the resin is impaired thereby, and the waterproofness of the diaphragm is lost.

  On the other hand, since the diaphragm 1 according to the embodiment of the present invention forms the air gap sealing layer 1a in which the air gap of the surface layer is filled, even the aqueous solution containing the surfactant is blocked by the surface layer. And will not enter the interior. As a result, high waterproofness can be obtained, and weight increase due to resin impregnation can be avoided.

  This fiber base material 1A can be formed from papermaking bodies of various fibers. In that case, natural fiber, chemical fiber, inorganic fiber, etc. can be arbitrarily selected according to the purpose, and the required diaphragm characteristics can be designed. Various physical properties such as internal loss can be adjusted to some extent.

  FIG.1 (c) shows the 2nd Embodiment of this invention, The diaphragm 1 which concerns on this embodiment forms the resin coating 1e on the surface of 1 A of fiber base materials mentioned above. . In the illustrated example, the resin coating 1e is formed on the main surface side and the back surface of the diaphragm 1. However, the present invention is not limited to this, and the resin coating 1e is formed on one surface of the main surface and the back surface. May be formed.

  According to this, in addition to the action of the diaphragm 1 having the gap sealing layer 1a described above, it is possible to obtain a high waterproofing effect by the resin coating 1e, and in particular, even for an aqueous solution containing a surfactant. Sufficient durability can be obtained.

  FIG. 2 is an explanatory diagram for explaining a method of manufacturing the speaker diaphragm according to the above-described embodiment of the present invention.

  According to this manufacturing method, one has a fiber base material forming step S10 including a mixing / papermaking step S1 and a drying / forming step S2. Moreover, it has resin film formation process S11 which has immersion process S3 and drying process S4 through this fiber base material formation process S10.

  The mixing / papermaking step S1 is a step of making paper by mixing various fiber materials and heat-expandable unexpanded particles (for example, unexpanded particles). FIG. 3 is an explanatory diagram for explaining an example of the mixing / papermaking step S1. Here, a raw material slurry 10 in which various fiber materials and heat-expandable unexpanded particles are mixed is stored in a mixing container 11, and a papermaking mold 13 in which a papermaking mesh 12 is placed on a mold having a desired shape is used as the raw material slurry. 10, and sucked by the suction device 14 to adhere the raw slurry 10 onto the papermaking net 12.

  The unexpanded particles used at this time enter between the fibers and expand by a subsequent heat treatment to fill the voids between the fibers. The smaller the particle diameter, the more effective is to enter between the fibers and fill the voids. However, if the particle diameter is made too small, the ratio of falling off from the mesh of the papermaking mesh 12 becomes higher at the time of papermaking. It is necessary to use those having a particle diameter of, for example, those having a particle diameter of about 10 to 20 μm.

  In general, the specific gravity of such unexpanded particles is higher than the specific gravity of water. In the papermaking process, when the raw material slurry 10 is sucked by the papermaking mold 13 having a desired shape, the unexpanded particles are not expanded near the mesh of the papermaking mesh 12. Particles will collect. Therefore, for example, when it is desired to form the air gap sealing layer 1 a on the back surface of the diaphragm 1, in order to concentrate unexpanded particles on the back surface of the diaphragm 1, paper making is performed in a direction in which the back surface is in contact with the mesh surface of the papermaking mold 13. .

  Thus, the part which forms the air gap sealing layer 1a can be selected depending on whether the main surface or the back surface of the diaphragm 1 is made to face upward during paper making. In addition, the effect of airtightness (waterproofness) increases as the amount of the unexpanded particles increases. However, when the amount is 20% or more, the effect is almost the same. Up to about%.

  The subsequent drying / forming step S2 is a step of forming the fiber base material 1A having the air gap sealing layer 1a by heating and pressing the papermaking body by the mixing / papermaking process. The papermaking body is put into a mold having the shape of the diaphragm 1 and heated and pressed. At this time, since the surface of the papermaking body is heated, the unexpanded particles concentrated on the surface layer are expanded by the heating to fill the gaps between the fibers, and the air gap sealing layer 1 a is formed on the surface layer of the diaphragm 1.

  The immersion step S3 is a step of immersing the formed fiber base 1A in a waterproof resin treatment liquid. When a substrate on which the above-described void sealing layer 1a is not formed is dipped in the treatment liquid, a large amount of resin is impregnated inside the substrate and the weight of the substrate is increased. Even if the fiber substrate 1A is soaked in the treatment liquid, the surface layer of the fiber substrate 1A has no voids, so that the resin does not penetrate into the interior, and the resin only adheres to the surface. The resin adhered in the subsequent drying step S4 is turned into a film to cover the surface of the diaphragm 1, and the resin film 1e is formed. The amount of resin adhering to the resin film 1e is considerably smaller than the amount of resin impregnated into the base material when the void sealing layer 1a is not formed. Therefore, the formation of the resin film 1a reduces the weight of the diaphragm 1 and can provide high waterproofness.

  Examples of the present invention will be described below. The following formulation examples are examples, and are not particularly limited thereto.

  [Example 1] First, as a fiber material to be mixed, NUKP (unleaved kraft pulp) is beaten to about 20 ° SR (shopper rigger), and 60 parts by weight of the low-boiling hydrocarbon is used as a heating expansion component. The unexpanded particles having a particle diameter of about 10 to 20 μm are used as the chemical fibers, and for example, 10 thermoplastic polyethylene fibers having a fiber length of about 2 to 4 mm are used. Part by weight, and further, a polyamide fiber having a fiber length of about 3 mm is blended at a ratio of 10 parts by weight to make a paper (mixing / paper making process).

  Thereafter, the fiber base 1A of the diaphragm 1 is formed by heating and pressing at a pressure of about 3 kg / cm 2 with a mold having a desired shape heated to about 180 ° C. (drying / molding step).

  In the soaking step, for example, a treatment liquid in which about 5% of a silicone resin is blended in an acrylic resin solution diluted to about 30% is prepared, and the fiber substrate 1A formed therein is soaked. Then, it is dried for about 15 minutes with a dryer at about 100 ° C. (drying step).

  [Example 2] First, as a fiber material to be mixed, NUKP is beaten to about 20 ° SR, and 40 parts by weight of this is used as a thermal expansion component. Using unexpanded particles of about 10 to 20 μm, 10 parts by weight of this, and as chemical fibers, for example, 10 parts by weight of polyethylene-based thermoplastic fibers with a fiber length of about 2 to 4 mm, and inorganic fibers with a fiber length of about 3 mm 10 parts by weight of glass fiber and further 30 parts by weight of mica powder having an average particle size of about 0.4 mm are mixed and made (mixing / making process).

  Thereafter, the fiber base 1A of the diaphragm 1 is formed by heating and pressing at a pressure of about 3 kg / cm 2 with a mold having a desired shape heated to about 180 ° C. (drying / molding step).

  In the soaking step, for example, a treatment liquid in which about 2% of a fluororesin is blended with an acrylic resin solution diluted to about 30% is prepared, and the fiber substrate 1A formed therein is soaked. Then, it is dried for about 15 minutes with a dryer at about 100 ° C. (drying step).

  [Comparative Example] A raw material obtained by beating NUKP to about 20 ° SR was made into a paper, and a diaphragm impregnated with the same treatment liquid as in Example 1 was manufactured.

  Table 1 shows the difference in the amount of resin adhesion between Examples 1 and 2 and the Comparative Example.

  As is apparent from Table 1, in Examples 1 and 2, the amount of resin adhered can be reduced as compared with the comparative example. This is because the resin does not penetrate into the inside of the fiber base 1A due to the air gap sealing layer 1a formed in Examples 1 and 2, and in Examples 1 and 2, an increase in the weight of the diaphragm can be avoided. Moreover, high waterproofness can be obtained by the resin film 1e.

  Table 2 shows the results of air permeability tests based on JIS P 8117 for the resin base materials according to Examples 1 and 2 and Comparative Examples in order to compare the air permeability.

  As is clear from the results in Table 2, it was confirmed that the fiber substrates of Examples 1 and 2 had almost no air permeability. Furthermore, by forming the resin film 1e on the surface, it has a structure that does not allow water or detergent solution for car washing to pass through. Actually, a cone-shaped diaphragm having an inner diameter opening closed was formed, and a detergent solution for car washing diluted to 5% with water was put on the main surface side and left for 24 hours. In Examples 1 and 2, the detergent solution Penetration into the substrate was not observed. On the other hand, in the comparative example, penetration into the base material was confirmed in about 30 minutes.

  Table 3 shows the physical property values of the diaphragms according to Examples 1 and 2 and the comparative example. As is apparent from this table, Examples 1 and 2 obtain moderate internal loss and effective Young's modulus while maintaining the low density and light weight, which are the advantages of the conventional diaphragm made of paper.

  As described above, according to the speaker diaphragm and the method for manufacturing the same according to the embodiment or examples of the present invention, while making full use of the advantages of the speaker diaphragm made of fiber, the waterproof property, particularly the surfactant. A loudspeaker diaphragm having excellent durability against an aqueous solution containing a water can be obtained.

It is explanatory drawing explaining the diaphragm for speakers which concerns on embodiment of this invention. It is explanatory drawing explaining the manufacturing method of the diaphragm for speakers which concerns on embodiment of this invention. It is explanatory drawing explaining the manufacturing method (mixing and papermaking process) of the diaphragm for speakers which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diaphragm 1A Fiber base material 1a Air gap sealing layer 1b Fiber 1c Heat expansion component 1e Resin film 10 Raw material slurry 11 Mixing container 12 Papermaking net 13 Paper making type 14 Suction device

Claims (5)

A speaker diaphragm composed of at least three layers formed by sucking a papermaking material mixed with a fiber base material and a heat expansion component ,
The surface layer on the non-suction side of the speaker diaphragm includes a first layer formed mainly of the fiber base material, and the heating expansion component expanded by heating is tightly sealed, and a gap between the fiber base materials is sealed. And the third layer formed on the back surface portion on the suction side of the speaker diaphragm, and between the first layer and the third layer, the heating expansion component is sparse in the fiber substrate. speaker diaphragm, characterized by comprising a second layer, the contained. The speaker diaphragm according to claim 1, wherein a resin film is formed on at least one of a front surface and a back surface of the speaker diaphragm. 3. The speaker diaphragm according to claim 1 , wherein the fiber substrate is made of a plurality of types of fibers selected according to the purpose . A method of manufacturing a speaker diaphragm,
Slurry the water, a plurality of fiber materials, and a heat-expandable unexpanded particle having a specific gravity higher than water, and suction the slurry through a paper mesh placed on a predetermined shape of the paper mesh A step of constructing a paper base comprising a plurality of fiber materials and the non-expanded particles non-uniformly, and a step of heating and pressurizing the paper to expand the unexpanded particles; Have
The surface layer on the non-suction side of the speaker diaphragm includes a first layer formed mainly of the fiber base material, and the heating expansion component expanded by heating is tightly sealed, and a gap between the fiber base materials is sealed. And the third layer formed on the back surface portion on the suction side of the speaker diaphragm, and between the first layer and the third layer, the heating expansion component is sparse in the fiber substrate. A speaker diaphragm comprising: a second layer included in the speaker; and a speaker diaphragm manufacturing method. The heated pressurized the papermaking product through漬浸step of漬浸the treatment liquid of the waterproof resin, claims, characterized in that to form the front and back surfaces of at least either one resin film of the papermaking product 4. A method for manufacturing a speaker diaphragm as described in 4 above .

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