Diaphragm

Abstract

To provide a diaphragm for a speaker which is lightweight and highly rigid.SOLUTION: A diaphragm 6 is formed in a conical shape (cone shape), and is formed so that a voice coil bobbin 5 can be fixed to an inner peripheral edge 61 thereof. The diaphragm 6 is formed of a lightweight material, and a concave part 63 is formed as a reinforcing structure in order to compensate for a decrease in rigidity due to a use of a lightweight material. The concave part 63 includes a first bent part 64 bent in a direction convex toward a sound emission direction in a middle part of the diaphragm 6, a second bent part 65 bent in a direction convex toward a side opposite to the sound emission direction on an outer peripheral side of the first bent part 64, and a third bent part 66 bent in a direction convex toward the sound emission direction on the outer peripheral side of the second bent part 65. The second bent part 65 and the third bent part 66 are formed in the vicinity of the outer peripheral edge 62.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a speaker diaphragm and a speaker device. [Background technology]

[0002] Speaker devices equipped with a cone-shaped diaphragm are known (see, for example, Patent Document 1). Fig. 1 is a schematic diagram of a conventional speaker device 901 equipped with a cone-shaped diaphragm 906. This speaker device 901 includes a frame 2, a magnetic circuit 3 forming a magnetic gap G, a voice coil 4 inserted into the magnetic gap G, a voice coil bobbin 5 around which the voice coil 4 is wound, a diaphragm 906 to which the voice coil bobbin 5 is fixed, an edge 7 that attaches the diaphragm 906 to the frame 2, a damper 8, and a center cap 9. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-152710 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present application attempted to use lightweight materials to reduce the weight of the cone-shaped speaker diaphragm described above, but using lightweight materials resulted in a problem of reduced rigidity of the diaphragm, which resulted in a loss of sound quality, making it difficult to achieve both weight reduction and sufficient rigidity.

[0005] Therefore, one example of a problem to be solved by the present invention is to provide a lightweight and highly rigid speaker diaphragm and a speaker device including the diaphragm. [Means for solving the problem]

[0006] The diaphragm of the present invention is a cone-shaped speaker diaphragm having a defined axis and outer periphery, and in a cross-sectional view including the axis, a recessed portion is formed on the opposite side to the sound output direction, and the recessed portion includes a first bent portion bent in a direction that is convex toward the sound output direction at the middle of the diaphragm, a second bent portion bent in a direction that is convex toward the opposite side to the sound output direction on the outer periphery side of the first bent portion, and a third bent portion bent in a direction that is convex toward the sound output direction on the outer periphery side of the second bend, and is characterized in that the distance along the diaphragm from the first bent portion to the second bent portion is greater than the distance along the diaphragm from the second bent portion to the outer periphery edge of the diaphragm. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating the configuration of a conventional speaker device. [Figure 2] 1 is a schematic diagram illustrating the configuration of a speaker device including a diaphragm according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a perspective view of the diaphragm of FIG. 2. [Figure 4] FIG. 4 is a plan view of the diaphragm of FIG. 3. [Figure 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. [Figure 6] FIG. 6 is an enlarged view of a main part of the diaphragm of FIG. 5. [Figure 7] 4 is a table showing changes in stiffness of the diaphragm of the present invention, the conventional diaphragm, and the diaphragm of the comparative example shown in FIG. 3. [Figure 8] 4 is a graph showing frequency characteristics of the diaphragm of the present invention and a diaphragm of a comparative example in FIG. 3. [Figure 9] FIG. 10 is a perspective view of a diaphragm according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a plan view of the diaphragm of FIG. 9. [Figure 11] FIG. 11 is a cross-sectional view taken along line BB in FIG. [Figure 12] FIG. 12 is an enlarged view of a main part of the diaphragm of FIG. [Figure 13] FIG. 10 is a perspective view of a diaphragm according to a third embodiment of the present invention. [Figure 14] FIG. 14 is a plan view of the diaphragm of FIG. 13. [Figure 15] FIG. 15 is a cross-sectional view taken along line CC in FIG. [Figure 16] FIG. 10 is a perspective view of a diaphragm according to a fourth embodiment of the present invention. [Figure 17] FIG. 17 is a plan view of the diaphragm of FIG. 16. [Figure 18] FIG. 18 is a cross-sectional view taken along line DD in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present invention will be described below. The diaphragm according to the embodiment of the present invention is a cone-shaped speaker diaphragm having a defined axis and an outer periphery. In a cross-sectional view including the axis, a recessed portion is formed on the side opposite the sound-emitting direction. The recessed portion includes a first bent portion bent in a direction convex toward the sound-emitting direction at a midpoint of the diaphragm, a second bent portion bent in a direction convex toward the side opposite the sound-emitting direction from the first bent portion on the outer periphery side, and a third bent portion bent in a direction convex toward the sound-emitting direction from the second bent portion on the outer periphery side. The distance along the diaphragm from the first bent portion to the second bent portion is greater than the distance along the diaphragm from the second bent portion to the outer periphery of the diaphragm. According to the present invention, forming the recessed portion in the diaphragm can increase rigidity. Therefore, by forming the diaphragm with the above configuration from a lightweight material, it is possible to achieve both weight reduction and rigidity.

[0009] A diaphragm according to one embodiment of the present invention is a cone-shaped speaker diaphragm having a defined axis and an outer periphery. In a cross-sectional view including the axis, a recessed portion is formed on the side opposite the sound output direction. The recessed portion includes a first bent portion bent in a convex direction toward the sound output direction at a midpoint of the diaphragm, a second bent portion bent in a convex direction toward the opposite side of the sound output direction from the first bent portion on the outer periphery side, and an outer periphery of the diaphragm. The distance along the diaphragm from the first bent portion to the second bent portion is greater than the distance along the diaphragm from the second bent portion to the outer periphery of the diaphragm. According to the present invention, forming the recessed portion in the diaphragm can increase rigidity. Therefore, by forming the diaphragm with the above configuration from a lightweight material, it is possible to achieve both weight reduction and rigidity.

[0010] The diaphragm may have the recess formed over the entire periphery thereof.

[0011] Furthermore, in a cross-sectional view including the axis, the vibration plate may have a portion extending from the first bend toward the axis having a constant curvature, and the portion from the first bend to the second bend may have a curvature equal to that of the portion extending from the first bend toward the axis.

[0012] Furthermore, in a cross-sectional view including the axis, the vibration plate may have a portion extending from the first bend portion toward the axis having a certain curvature, and the outer edge of the vibration plate may be located on an imaginary circle formed by that portion.

[0013] A speaker device according to an embodiment of the present invention includes the above diaphragm. [Example]

[0014] (First Example) 2 is a schematic diagram of a speaker device 1 equipped with a diaphragm 6 according to a first embodiment of the present invention. This speaker device 1 includes a frame 2, a magnetic circuit 3 supported by the frame 2 and forming a magnetic gap G, a voice coil 4 inserted into the magnetic gap G, a cylindrical voice coil bobbin 5 around which the voice coil 4 is wound, a diaphragm 6 to which the voice coil bobbin 5 is fixed, an edge 7 that attaches the diaphragm 6 to the frame 2, a damper 8, and a center cap 9.

[0015] The magnetic circuit 3 is, for example, an external magnet type magnetic circuit, and is configured with an annular magnet 31, a yoke 32, and an annular top plate 33. The yoke 32 is configured with a bottom plate 34 and a center pole 35 standing upright from the center of the bottom plate 34. The center pole 35 is inserted into the center of the magnet 31, and the magnet 31 is stacked on the bottom plate 34. The center pole 35 is inserted into the center of the top plate 33, and the top plate 33 is stacked on the surface of the magnet 31 facing the diaphragm 6. A "magnetic gap G" is the gap between the top plate 33 and the center pole 35. This magnetic circuit 3 works in cooperation with the voice coil 4 to vibrate the diaphragm 6.

[0016] As shown in Figures 3 to 5, the diaphragm 6 is formed in a truncated cone shape (cone-type) and is formed so that the voice coil bobbin 5 can be fixed to its inner peripheral edge (neck) 61. In Figures 3 to 5, the dashed dotted line P indicates the axis of the diaphragm 6. In the plan view of Figure 4, the inner peripheral edge 61 and the outer peripheral edge 62 (corresponding to the outer periphery in the claims) of the diaphragm 6 are perfect circles, but the present invention is not limited to this, and the inner peripheral edge and the outer peripheral edge of the diaphragm may be ellipses. In a cross-sectional view including the axis P, the diaphragm 6 is gently curved from the inner peripheral edge 61 to the outer peripheral edge 62.

[0017] In order to reduce weight, the diaphragm 6 of this example is made of a lightweight material that is less rigid than conventional products. To compensate for the loss of rigidity caused by using a lightweight material, the following reinforcement structure is provided. That is, the diaphragm 6 has a recess 63 formed on the side opposite the sound output direction in a cross-sectional view including the axis P. The "sound output direction" is the direction opposite the voice coil 4 along the axis P. In this example, the recess 63 is formed around the entire periphery of the diaphragm 6.

[0018] 6, recess 63 includes a first bent portion 64 bent in a direction convex toward the sound output direction in the middle portion of diaphragm 6, a second bent portion 65 bent in a direction convex toward the opposite side to the sound output direction on the outer periphery side of first bent portion 64, and a third bent portion 66 bent in a direction convex toward the sound output direction on the outer periphery side of second bent portion 65. In other words, recess 63 is formed by being bent at three locations: first bent portion 64, second bent portion 65, and third bent portion 66. In this specification, "bent" does not mean smoothly curved, but means folded.

[0019] The "middle portion of the diaphragm 6" is the portion near the center between the inner peripheral edge 61 and the outer peripheral edge 62, and is the portion where the amplitude is particularly large in the resonant state in which the portion vibrates. A first bent portion 64 is formed at the point in the middle portion where the amplitude in the resonant state is largest.

[0020] The second bend 65 and the third bend 66 are formed near the outer peripheral edge 62. Therefore, the distance along the diaphragm 6 from the first bend 64 to the second bend 65 is greater than the distance along the diaphragm 6 from the second bend 65 to the outer peripheral edge 62 via the third bend 66. In this example, the outer diameter of the diaphragm 6 is about 120 mm, whereas the distance along the diaphragm 6 from the first bend 64 to the second bend 65 is about 20 mm, the distance along the diaphragm 6 from the second bend 65 to the third bend 66 is about 1 to 2 mm, and the distance along the diaphragm 6 from the third bend 66 to the outer peripheral edge 62 is about 5 mm.

[0021] 6, in a cross-sectional view of the diaphragm 6 including the axis P, the portion extending from the first bent portion 64 toward the axis P (toward the inner peripheral edge 61) has a constant curvature, and the portion from the first bent portion 64 to the second bent portion 65 and the portion from the third bent portion 66 to the outer peripheral edge 62 have the same curvature as the portion extending from the first bent portion 64 toward the axis P. Furthermore, the outer peripheral edge 62 of the diaphragm 6 is located on an imaginary circle formed by the portion extending from the first bent portion 64 toward the axis P. The two-dot chain line F in FIG. 6 indicates a part of the imaginary circle.

[0022] That is, in the diaphragm 6 of this example, the portion from the middle to the outer periphery, which curves at a constant curvature, is bent at two locations, a first bent portion 64 and a second bent portion 65, and the outer periphery 62 is bent at a third bent portion 66 so as to return to the base curve (two-dot chain line F), thereby forming a recess 63. In this way, it is possible to reduce the weight of the diaphragm 6 and increase its rigidity without substantially changing the design or layout of the speaker device.

[0023] The edge 7 is formed in a ring shape in a plan view. In addition, in a cross-sectional view shown in FIG. 2 , the edge 7 is integrally configured to have an edge main body 71 formed in a convex arc shape in the sound output direction, an edge inner peripheral portion 72 continuous with the inner peripheral edge of the edge main body 71, and an edge outer peripheral portion 73 continuous with the outer peripheral edge of the edge main body 71. The edge inner peripheral portion 72 is adhered to a portion of the diaphragm 6 that is outer than the third bent portion 66. The edge outer peripheral portion 73 is attached to the frame 2.

[0024] The damper 8 is formed in an annular shape, with its inner peripheral edge attached to the voice coil bobbin 5 and its outer peripheral edge attached to the frame 2. The damper 8 allows the voice coil bobbin 5 and the diaphragm 6 to vibrate, while gradually damping these vibrations.

[0025] The center cap 9 is attached near the inner peripheral edge 61 of the diaphragm 6 and covers the opening of the voice coil bobbin 5 on the diaphragm 6 side.

[0026] FIG. 7 is a table showing the change in stiffness of the above-mentioned diaphragm 6 of the present invention (present invention product 1), a conventional diaphragm, and a diaphragm of a comparative example. The conventional diaphragm is a diaphragm with the shape shown in FIG. 1, and is a diaphragm with a shape (along the two-dot chain line F in FIG. 6) in which the recess 63 is eliminated from the diaphragm 6 of the present invention. The conventional diaphragm is made of a standard material. The comparative diaphragm has the same shape as the conventional diaphragm, and is made of the same lightweight material as the diaphragm 6 of the present invention. Each stiffness value in FIG. 7 is the stiffness value (unit: [N / mm]) when the inner peripheral edge of the diaphragm is fixed and a predetermined external force is applied to the outer periphery.

[0027] 7 shows that the comparative example using a lightweight material has lower stiffness than the conventional product, but product 1 of the present invention (diaphragm 6) using a lightweight material and having recesses 63 has higher stiffness than the conventional product. In other words, product 1 of the present invention (diaphragm 6) is lighter in weight than the conventional product and also has higher stiffness than the conventional product.

[0028] 8 is a graph showing the frequency characteristics obtained as a result of performing a simulation under certain conditions for the above-mentioned diaphragm 6 of the present invention (product 1 of the present invention) and a diaphragm of a comparative example. The diaphragm of the comparative example is the same as the diaphragm of the comparative example in the table of FIG.

[0029] 8, it can be seen that the peak around 1 kHz, which is the resonance with the edge, of the present invention 1 (diaphragm 6) is shifted to the higher frequency side compared to the comparative example. This is because the second bent portion 65 and the third bent portion 66 are formed near the outer periphery 62, thereby strengthening the rigidity of the outer periphery side of the present invention 1 (diaphragm 6).

[0030] 8, it can be seen that the peak around 4 kHz, where the amplitude of the resonant state in the middle part of the diaphragm becomes large, is changed to a dispersed shape (flattened) in the present invention product 1 (diaphragm 6) compared to the comparative example. In other words, the frequency characteristics of the present invention product 1 (diaphragm 6) as a speaker are better than those of the comparative example. This is due to the fact that the first bent portion 64 is formed in the middle part of the diaphragm 6.

[0031] Furthermore, since the shape of the recessed portion 63 of the diaphragm 6 of the present invention is simple, weight increase can be suppressed (weight increases with a complex reinforcement structure), and it is easy to manufacture a mold for the diaphragm 6. Furthermore, since the diaphragm 6 of the present invention has the recessed portion 63 formed on the inner periphery side of the portion to which the inner periphery edge portion 72 is bonded (the portion outer than the third bent portion 66), the operation of bonding the inner periphery edge portion 72 to the diaphragm 6 can be easily performed.

[0032] (Second Example) 9 to 12 are diagrams showing a diaphragm 106 according to a second embodiment of the present invention. In Figs. 9 to 12, the same components as those in the above-described embodiments are given the same reference numerals, and their description will be omitted. Diaphragm 106 of this embodiment also constitutes a speaker device in the same way as in the first embodiment.

[0033] As shown in FIGS. 9 to 11, diaphragm 106 is formed in a truncated cone shape (cone type) and is formed so that a voice coil bobbin can be fixed to its inner peripheral edge (neck) 61. Diaphragm 106 of this example is made of a lightweight material to reduce weight. In addition, to compensate for the loss of rigidity caused by using a lightweight material, the following reinforcement structure is provided. That is, diaphragm 106 has a recess 163 recessed on the side opposite to the sound output direction in a cross-sectional view including axis P. In this example, recess 163 is formed around the entire periphery of diaphragm 106.

[0034] 12, recess 163 includes a first bent portion 64 bent in a direction convex toward the sound output direction in the middle portion of diaphragm 106, a second bent portion 65 bent in a direction convex toward the opposite side to the sound output direction on the outer periphery side of first bent portion 64, and outer periphery edge 62 of diaphragm 106. In other words, recess 163 is formed by being bent at two locations, first bent portion 64 and second bent portion 65.

[0035] The second bent portion 65 is formed near the outer peripheral edge 62. Therefore, the distance along the diaphragm 106 from the first bent portion 64 to the second bent portion 65 is formed to be greater than the distance along the diaphragm 106 from the second bent portion 65 to the outer peripheral edge 62.

[0036] 12, in a cross-sectional view of diaphragm 106 including axis P, the portion extending from first bent portion 64 toward axis P (toward inner peripheral edge 61) has a constant curvature, and the portion from first bent portion 64 to second bent portion 65 and the portion from second bent portion 65 to outer peripheral edge 62 have the same curvature as the portion extending from first bent portion 64 toward axis P. Furthermore, outer peripheral edge 62 of diaphragm 106 is located on an imaginary circle formed by the portion extending from first bent portion 64 toward axis P. A two-dot chain line F in FIG. 12 indicates a part of the imaginary circle.

[0037] That is, in this example, diaphragm 106 is bent at first bend 64 from the middle portion curved at a constant curvature toward the outer periphery, and then bent at second bend 65 so that outer periphery 62 returns to the base curve (two-dot chain line F), forming recess 163. In this example, the edge is bonded to the portion toward the outer periphery beyond second bend 65. In this way, it is possible to reduce the weight of diaphragm 106 and increase its rigidity without substantially changing the design or layout of the speaker device.

[0038] As with Example 1, diaphragm 106 of this example is lighter in weight than the conventional product and has increased rigidity compared to the conventional product. Furthermore, since the shape of recess 163 is simple, weight increase can be suppressed and the mold for molding diaphragm 106 can be easily produced.

[0039] (Third Example) 13 to 15 are diagrams showing a diaphragm 206 according to a third embodiment of the present invention. In Figs. 13 to 15, the same components as those in the above-described embodiments are given the same reference numerals, and their description will be omitted. Diaphragm 206 of this embodiment also constitutes a speaker device in the same way as in the first embodiment.

[0040] As shown in Figures 13 to 15, diaphragm 206 is formed in a truncated cone shape (cone type) and is formed so that a voice coil bobbin can be fixed to its inner peripheral edge (neck) 61. Diaphragm 206 in this example is formed of a lightweight material to reduce weight. In addition, to compensate for the loss of rigidity caused by using a lightweight material, the following reinforcing structure is provided. That is, diaphragm 206 has a recess 263 recessed on the side opposite to the sound output direction in a cross-sectional view including axis P.

[0041] In the first and second embodiments, recesses 63, 163 were formed around the entire circumference of the diaphragm, but in this example, a portion 267 in the circumferential direction of diaphragm 206 is left in a rib-like shape rather than being formed as a recess 263. In this example, this rib-like portion 267 is formed in five places, and five recesses 263 are formed in the circumferential direction of diaphragm 206.

[0042] Each recess 263 has the same shape as the recess 63 of the first embodiment in a cross-sectional view including the axis P in Fig. 15. Furthermore, the rib-like portion 267 is curved at a constant curvature in a cross-sectional view including the axis P in Fig. 15. That is, the shape follows the two-dot chain line F in Fig. 6. Furthermore, the rib-like portion 267 is formed to have a uniform thickness.

[0043] (Fourth Example) 16 to 18 are diagrams showing a diaphragm 306 according to a fourth embodiment of the present invention. In Figs. 16 to 18, the same components as those in the above-described embodiments are given the same reference numerals, and the description thereof will be omitted. Diaphragm 306 of this embodiment also constitutes a speaker device in the same manner as in the first embodiment.

[0044] As shown in Figures 16 to 18, diaphragm 306 is formed in a truncated cone shape (cone type) and is formed so that a voice coil bobbin can be fixed to its inner peripheral edge (neck) 61. Diaphragm 306 in this example is made of a lightweight material to reduce weight. In addition, to compensate for the loss of rigidity caused by using a lightweight material, the following reinforcing structure is provided. That is, diaphragm 306 has a recess 363 recessed on the side opposite to the sound output direction in a cross-sectional view including axis P.

[0045] In this example, similar to the third embodiment, a portion 367 in the circumferential direction of diaphragm 306 is left in a rib shape rather than being made into a recess 363. In this example, these rib-shaped portions 367 are formed in five places, and five recesses 363 are formed in the circumferential direction of diaphragm 306. In addition, rib-shaped portion 367 is formed to have a smaller width than rib-shaped portion 267 in the third embodiment.

[0046] Each recess 363 has the same shape as the recess 263 of the third embodiment in a cross section including the axis P in Fig. 18. However, the circumferential width of each recess 363 is larger than that of the recess 263 of the third embodiment. Furthermore, the rib-like portion 367 is formed so that its thickness gradually increases from the inner periphery toward the outer periphery in a cross section including the axis P in Fig. 18.

[0047] The diaphragms of Examples 1 to 4 described above were gently curved from the inner peripheral edge 61 to the outer peripheral edge 62 when viewed in a cross section including the axis P, but the diaphragm of the present invention may have a straight shape from the inner peripheral edge to the outer peripheral edge.

[0048] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and the present invention also includes design changes within the scope of the present invention. The examples shown in the above figures can be combined with each other as long as there are no particular contradictions or problems in their purpose, configuration, etc. Furthermore, the contents of each figure can each be an independent embodiment, and the embodiment of the present invention is not limited to a single embodiment obtained by combining the figures. [Explanation of symbols]

[0049] 1. Speaker device 6,106,206,306 Vibration plate 61 Inner edge 62 outer edge 63,163,263,363 recess 64 1st bending part 65 2nd bending part 66 3rd bending part

Claims

[Claim 1] A cone-shaped speaker diaphragm having a defined axis and an outer periphery, In a cross-sectional view including the axis, a recessed portion is formed on the opposite side to the sound output direction, the recess includes a first bent portion bent in a direction convex toward the sound output direction at a middle portion of the diaphragm, a second bent portion bent in a direction convex toward the opposite side to the sound output direction at a position closer to the outer periphery than the first bent portion, and a third bent portion bent in a direction convex toward the sound output direction at a position closer to the outer periphery than the second bent portion, The distance along the diaphragm from the first bent portion to the second bent portion is greater than the distance along the diaphragm from the second bent portion to the outer periphery of the diaphragm. A diaphragm characterized by:

Images