Voice coil and speaker device using the same

Abstract

To provide a technology that realizes higher soundness while maintaining the heat dissipation effect of a voice coil.SOLUTION: A voice coil 20 includes a bobbin 1 formed in a substantially cylindrical shape, a coil 3 wound around the bobbin 1, and a plurality of protrusions 2 formed over the outer circumferential surface of the bobbin 1. In addition, a conductive foil 4 having protrusions and an insulating paper 5 having protrusions are attached to the outer circumferential surface of the bobbin 1. The voice coil 20 is used in a speaker device.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a voice coil and a speaker device using the voice coil. [Background technology]

[0002] Generally, a speaker device uses a voice coil as a sound generating source. This voice coil has a structure in which an insulated electric wire is wound as a coil around a core material called a coil bobbin, and the non-insulated end of the coil (electric wire) is electrically connected to a lead wire, for example, a tinsel wire. The bobbin that supports this coil bobbin usually has a plurality of slits formed at predetermined intervals in a direction intersecting the winding direction of the coil (see, for example, Patent Document 1).

[0003] In the technology of Patent Document 1, since the voice coil heats up when the output of the speaker device is increased, slits are provided in the bobbin to improve the heat dissipation effect of the coil. However, there is a problem in that the slits reduce the area of ​​contact between the bobbin and the electric wire, reducing the adhesive strength between the bobbin and the electric wire. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-142292 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to solve the above-mentioned problems by providing a technology that achieves higher soundness while maintaining the heat dissipation effect. [Means for solving the problem]

[0006] A voice coil according to one aspect of the present invention includes a bobbin formed in a substantially cylindrical shape, a coil wound around the bobbin, and a plurality of protrusions formed on the outer peripheral surface of the bobbin.

[0007] A speaker device according to one aspect of the present invention includes the above voice coil. [Effects of the Invention]

[0008] The coil bobbin of the present invention can achieve higher soundness while maintaining heat dissipation effect by virtue of the plurality of protrusions formed over the outer peripheral surface of the bobbin. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are diagrams illustrating a voice coil according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the voice coil shown in FIG. 1 taken along the line AA. [Figure 3] FIG. 2 is a perspective view of the bobbin of the voice coil of FIG. 1. [Figure 4] 10A and 10B are diagrams illustrating a voice coil according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a development view of the voice coil shown in FIG. [Figure 6] 6 is a cross section taken along the line BB of the conductive foil and insulating paper of the voice coil shown in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0011] Furthermore, the following embodiments are merely examples, and the present invention is not limited to these embodiments. Furthermore, a voice coil to which the present invention is applied is, for example, a voice coil for a speaker device, and the following embodiments illustrate the case where the present invention is applied to a voice coil for a speaker device.

[0012] Embodiment 1 A voice coil 10 according to the first embodiment will be described with reference to Figures 1, 2, and 3. Figure 1 is a diagram illustrating the voice coil according to the first embodiment. The voice coil 10 according to the first embodiment includes a bobbin 1, a protrusion 2, a coil 3, an electric wire 8, and a gap 9.

[0013] As shown in the front view of FIG. 1, this voice coil has a structure in which a coil 3 is wound around the outer peripheral surface of the lower part of a bobbin 1, which is shaped like a hollow cylinder, for example. The bobbin 1 has a plurality of small protrusions 2. The coil 3 is obtained by winding an electric wire 8 that is insulated by a coating, for example. The type of the electric wire 8 is not particularly limited. For example, enameled copper clad aluminum wire (CCAW) or the like may be used as the electric wire 8.

[0014] 2 is a cross-sectional view taken along the line A-A of the voice coil shown in FIG. 1. An electric wire 8 is wound around the upper portion of a protrusion 2 of the bobbin 1, and a coil 3 is formed on top of the protrusion 2. A space of a clearance 9 is formed between the bobbin 1 and the coil 3, and between the protrusion 2 and the coil 3. The protrusion 2 functions as a separating portion that separates the coil 3 from the outer peripheral surface of the bobbin 1.

[0015] FIG. 3 is a perspective view showing the bobbin shown in FIG. 1. The bobbin 1 is formed in a substantially cylindrical shape. A plurality of protrusions 2 are formed on the bobbin 1 around the entire outer periphery thereof. The protrusions 2 are formed so as to protrude from the outer periphery from the center of the bobbin 1 toward the outer periphery. The protrusions 2 may be formed in a shape like a grater, with burrs standing upright. This allows the protrusions 2 to play a role in retaining the movement of the electric wire 8, and to more firmly maintain the position of the electric wire 8.

[0016] The size of the protrusion 2 is preferably such that, when the coil 3 is wound around the bobbin 1 as shown in FIG. 2, a gap 9 is formed between the protrusion 2 and the coil 3. For example, the size of the protrusion 2 of the bobbin 1 is preferably 1 mm or less in length. The material of the bobbin 1 may be any of metals such as aluminum, polyimide film, glass fiber, meta-aramid fiber, and composites thereof. This reduces the weight of the bobbin 1 and improves its heat resistance. The protrusion 2 of the bobbin 1 may be formed by molding, for example, shearing or injection molding.

[0017] Next, an example of a method for manufacturing the voice coil 10 will be described. For example, a flat plate-like member having a plurality of protrusions 2 formed on one side thereof as shown in Fig. 5 (described later) is formed by shearing, injection molding, or the like. Next, the flat plate-like member is molded into a cylindrical shape with the plurality of protrusions 2 on the outer circumferential surface, thereby forming a substantially cylindrical bobbin 1 as shown in Fig. 3.

[0018] An adhesive is applied to the surface of the substantially cylindrical bobbin 1, and an electric wire 8 is wound around it to form the coil 3 on the outer circumferential surface of the voice coil 10. The adhesive attached to the bobbin 1 and the coil 3 is dried to harden the adhesive, thereby forming the coil bobbin 10. The bobbin 1 having the above-described multiple protrusions 2 is molded using a flat plate-shaped member, but the substantially cylindrical bobbin 1 may also be formed from the beginning by casting or injection molding.

[0019] As shown in Figure 2, by providing multiple small protrusions 2 on the bobbin 1, gaps 9 are formed between the protrusions 2 and the coil 3, and between the bobbin 1 and the coil 3. This improves the heat dissipation of the coil bobbin 10, thereby improving the heat resistance of the voice coil and the speaker. By forming the protrusions 2 on the bobbin 1 into a burr-like shape, the position of the electric wire 8 is more firmly maintained, preventing the electric wires from slipping or falling off.

[0020] 1 and 2, in the present embodiment 1, by providing the protrusions 2 on the bobbin 1, the adhesive surface between the bobbin 1 and the electric wire 8 is maintained more tightly than when a slit is provided on the bobbin 1. As a result, the adhesive penetrates around the small protrusions 2, further improving the adhesive strength.

[0021] When slits are provided in the bobbin as in the prior art, individual design is required taking into account the coil structure. Furthermore, the slits reduce the overall mechanical strength of the bobbin, making the area around the slits particularly susceptible to breakage during coil winding. This makes the slit bobbin structure difficult to manufacture. On the other hand, by providing the protrusions 2 uniformly over the entire bobbin 1 as in the first embodiment, the bobbin is easier to manufacture and is less likely to be damaged during voice coil manufacturing, improving durability. Therefore, the bobbin 1 structure shown in FIG. 3 can be used for a variety of coils, making it highly versatile.

[0022] Embodiment 2 In the second embodiment of the present invention, unlike the first embodiment, a voice coil 20 in which a conductive foil 4 and insulating paper 5 are attached to a bobbin 1 will be described with reference to Figures 4, 5, and 6. Note that in the second embodiment, the description of the same points as in the first embodiment will be omitted, and the description will focus on the points that are different from the first embodiment.

[0023] 4 is a diagram illustrating a voice coil according to embodiment 2 of the present invention. The voice coil 20 according to embodiment 2 includes a bobbin 1, a protrusion 2, a coil 3, a conductive foil 4, insulating paper 5, an electric wire 8, and a gap 9.

[0024] Fig. 5 is an exploded view of the voice coil shown in Fig. 4, excluding the coil 3. Fig. 6 is a cross-sectional view taken along the line BB of the conductive foil and insulating paper of the voice coil shown in Fig. 5.

[0025] As shown in Figure 5, a conductive foil 4 is attached to the bobbin 1 so as to cover a portion of the outer peripheral surface of the bobbin 1 in the vertical direction, for example. As shown in Figures 5 and 6, the conductive foil 4 has a plurality of protrusions 2 on one side. The plurality of protrusions 2 of the conductive foil 4 are formed so as to protrude from the surface of the conductive foil 4. An insulating paper 5 is attached to the conductive foil 4. The insulating paper 5 has a plurality of protrusions 2 on one side. The plurality of protrusions 2 of the insulating paper 5 are formed so as to protrude from the surface of the insulating paper 5.

[0026] 6, by providing the conductive foil 4 with multiple small protrusions 2, a gap 9 is formed as a space between the conductive foil 4 and the insulating paper 5, and a gap 9 is also formed as a space between the insulating paper 5 and the coil 3 together with the protrusions 2. Here, the multiple protrusions 2 of the conductive foil 4 form the protrusions of the conductive foil 4. Furthermore, the multiple protrusions 2 of the insulating paper 5 form the protrusions of the insulating paper 5.

[0027] Next, an example of a method for manufacturing the voice coil 20 will be described. In the second embodiment, a conductive foil 4 and insulating paper 5 are attached to a bobbin 1. As shown in FIG. 5, the conductive foil 4 is attached so that the side of the conductive foil 4 that does not have the protrusions 2 overlaps the bobbin 1 that has a plurality of protrusions 2. Next, the insulating paper 5 is attached so that the side of the insulating paper 5 that does not have the protrusions 2 overlaps the conductive foil 4 attached to the bobbin 1. As a result, as shown in FIGS. 5 and 6, the protrusions 2 of any of the bobbin 1, conductive foil 4, and insulating paper 5 are located in places where no coil 3 exists.

[0028] A bobbin may use conductive foil and insulating paper as a connection circuit for lead wires or tinsel wires. However, when a coil is wound on such a bobbin, the resulting multi-layer structure of the bobbin, conductive foil, and insulating paper results in a further deterioration of heat dissipation. On the other hand, in the second embodiment, the heat dissipation between the bobbin 1 and conductive foil 4 is improved, so that the problem of gas generation due to volatilization of adhesive components in each layer can be solved, even in the case of a multi-layer structure.

[0029] 5 and 6, in the second embodiment, the conductive foil 4 and the insulating paper 5 are also provided with protrusions 2, thereby maintaining a tight contact surface between the insulating paper 5 and the electric wire 8. This allows the adhesive to penetrate around the small protrusions 2, further improving the adhesive strength.

[0030] Next, the operation will be described. The speaker device has a configuration such as that shown in FIG. 1 of Patent Document 1, for example. The voice coil 10 shown in the above-mentioned first embodiment is used, for example, as a voice coil for a speaker. When a current flows through the coil 3, an upward or downward driving force acts on the voice coil 10 depending on the direction of the current. The voice coil 10 is movable, and the driving force acting on the voice coil 10 is transmitted to a diaphragm (not shown) via the bobbin 1, generating sound. The same applies when the voice coil 20 shown in the above-mentioned second embodiment is used as a voice coil for a speaker.

[0031] Next, we will explain the testing of a speaker device using voice coils 20. The speaker device is equipped with six voice coils 20 as shown in Figure 4. The voice coils 20 are ribbon wire type with a single layer winding. A conductive foil 4 is attached to the bobbin 1 to solder the copper wire at the end of the coil 3 winding.

[0032] First, we will explain the reliability test of the voice coil 20 using the bobbin 1. The conditions for this test are as follows. <Exam conditions> Voltage: 42.8V Frequency: 50~500Hz Time: 100 hours Reasons for failure: Falling wire, etc.

[0033] The reliability test results showed that all six voice coils 20 passed. The width of the winding of any of the voice coils 20 did not increase, and no wires fell off the bobbins 1.

[0034] Next, an accelerated test was conducted. With a conventional voice coil with slits, the wire fell off from the bobbin at approximately 330°C to 340°C. On the other hand, with voice coil 20, the wire did not fall off from bobbin 1 up to approximately 390°C to 400°C, confirming the effect of improved heat resistance.

[0035] Furthermore, even in the case of the coil bobbin 10 shown in FIG. 1, which does not use conductive foil, it is believed that the heat dissipation, heat resistance, and adhesion will be improved in the same way as the coil bobbin 20.

[0036] Although the coil bobbin and the speaker device using the same according to the present invention have been described above as embodiments, the present invention is not limited to the described embodiments, and various modifications can be made within the scope of the claims. Note that the embodiment described below, including modified examples, is merely an example, and the technical scope of the present invention is not limited to this. Various modified examples are also included within the technical scope of the present invention.

[0037] In the embodiment described above, the bobbin is used for a voice coil, but since the bobbin also improves durability, the structure of the bobbin 1 may be used for various coils other than a voice coil.

[0038] In the embodiment described above, the protrusions 2 are provided around the entire circumference of the bobbin 1, but the protrusions 2 may be provided only on the portion of the bobbin 1 where the coil 3 is wound. Also, the protrusions 2 may be provided only on the conductive foil 4 and insulating paper 5 where the coil 3 is wound.

[0039] Regarding the manufacturing method for manufacturing the voice coil 10, the procedure or steps in the manufacturing method are not particularly limited, and various modifications are possible. [Explanation of symbols]

[0040] 1 coil bobbin, 2 protrusion, 3 coil, 4 conductive foil, 5 insulating paper, 8 electric wire, 9 gap, 10, 20 voice coil

Claims

1. a bobbin formed in a substantially cylindrical shape; a coil wound on the bobbin; a plurality of protrusions protruding from the outer peripheral surface of the bobbin and formed over the entire circumference of the outer peripheral surface including the portion around which the coil is wound.

2. A conductive foil having a protrusion is attached to the outer circumferential surface of the bobbin.

2. The voice coil of claim 1.

3. The protruding portion of the conductive foil is formed so that a plurality of protruding portions protrude from the outer peripheral surface of the conductive foil.

3. The voice coil of claim 2.

4. An insulating paper having a protrusion is attached to the conductive foil.

4. The voice coil according to claim 2 or 3.

5. The voice coil according to claim 4 , wherein the protrusion of the insulating paper is formed so as to protrude from the outer peripheral surface of the insulating paper.

6. The protrusion has a length of 1 mm or less.

2. The voice coil of claim 1.

7. The material of the bobbin is made of any one of metal, polyimide film, glass fiber, meta-aramid fiber, and a composite thereof.

7. A voice coil according to claim 1, 2, 3 or 6.

8. A voice coil according to any one of claims 1, 2, 3 and 6 is provided. Speaker device.

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