Diaphragm, loudspeaker device

Abstract

To provide a diaphragm for a loudspeaker, having light weight and high rigidity.SOLUTION: A diaphragm 6 is formed in a truncated conical shape (a corn shape), and is formed in such a manner that a voice coil bobbin 5 can be fixed to the inner peripheral edge 61 of the diaphragm 6. The diaphragm 6 is formed of a light material, and has a convex portion 63 as reinforcement structure for reinforcing deterioration of rigidity due to the use of the light material. The convex portion 63 includes: a first bent portion 64 that is bent to a direction in which it becomes a convex shape on a sound discharge direction side in a middle abdominal portion of the diaphragm 6; a second bent portion 65 that is bent to a direction in which it becomes a convex shape in reverse to the sound discharge direction on an outer peripheral side from the first bent portion 64; and a third bent portion 66 that is bent to a direction in which it becomes the convex shape to the sound discharge direction side on the outer peripheral side from the second bent portion 65. The second bent portion 65 and the third bent portion 66 are formed near an 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] JP 2018-152710 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present application attempted to form the above-mentioned cone-shaped speaker diaphragm using a lightweight material in order to reduce its weight. However, when a lightweight material is used, the rigidity of the diaphragm decreases, causing a problem of loss of sound quality, and it was not easy 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 an outer periphery, and in a cross-sectional view including the axis, a recess is formed on the opposite side to the sound output direction, and the recess includes a first bent portion bent in a direction convex toward the sound output direction at the middle of the diaphragm, a second bent portion bent in a direction convex toward the opposite side to the sound output direction on the outer periphery side from the first bend, and a third bent portion bent in a direction convex toward the sound output direction on the outer periphery side from the second bend, and the distance along the diaphragm from the first bend to the second bend is greater than the distance along the diaphragm from the second bend to the outer periphery of the diaphragm, and in a cross-sectional view including the axis, a portion extending from the first bend to the axis side has a constant curvature, and the outer periphery of the diaphragm is located on a virtual circle formed by the portion.

[0007] A speaker device according to the present invention includes the above-mentioned diaphragm. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a conventional speaker device. [Diagram 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. [Diagram 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. [Diagram 5] FIG. 5 is a cross-sectional view taken along the line AA in FIG. [Figure 6] 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 shown in FIG. 3, a conventional diaphragm, and a diaphragm of a comparative example. [Figure 8] 4 is a graph showing frequency characteristics of the diaphragm of the present invention in FIG. 3 and a diaphragm of a comparative example. [Figure 9] FIG. 11 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. [Figure 11] FIG. 11 is a cross-sectional view taken along line BB in FIG. [Figure 12] 12 is an enlarged view of a main part of the diaphragm of FIG. 11. [Figure 13] FIG. 11 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] 15 is a cross-sectional view taken along line CC in FIG. 14. [Figure 16] FIG. 13 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 PREFERRED EMBODIMENTS

[0009] An embodiment of the present invention will be described below. The diaphragm according to an embodiment of the present invention is a cone-shaped speaker diaphragm having a fixed axis and an outer periphery, and in a cross-sectional view including the axis, a recess is formed on the opposite side to the sound output direction, and the recess includes a first bent portion bent in a direction convex toward the sound output direction at the middle of the diaphragm, a second bent portion bent in a direction convex toward the opposite side to the sound output direction on the outer periphery side from the first bent portion, and a third bent portion bent in a direction convex toward the sound output direction on the outer periphery side from the second bent portion, and the distance along the diaphragm from the first bent portion to the second bent portion is formed to be larger than the distance along the diaphragm from the second bent portion to the outer periphery edge of the diaphragm. According to the present invention, the rigidity can be increased by forming the recess in the diaphragm. Therefore, by forming the diaphragm of the above configuration from a lightweight material, it is possible to achieve both weight reduction and rigidity.

[0010] The diaphragm according to one embodiment of the present invention is a cone-shaped speaker diaphragm having a fixed axis and an outer periphery, and in a cross-sectional view including the axis, a recess is formed on the opposite side to the sound output direction, and the recess includes a first bent portion bent in a direction convex toward the sound output direction at the middle of the diaphragm, a second bent portion bent in a direction convex toward the opposite side to the sound output direction on the outer periphery side of the first bent portion, and an outer periphery of the diaphragm, and the distance along the diaphragm from the first bent portion to the second bent portion is formed to be greater than the distance along the diaphragm from the second bent portion to the outer periphery of the diaphragm. According to the present invention, the rigidity can be increased by forming the recess in the diaphragm. Therefore, by forming the diaphragm of the above configuration from a lightweight material, it is possible to achieve both weight reduction and rigidity.

[0011] Moreover, the diaphragm may have the recess formed over the entire periphery of the diaphragm.

[0012] 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.

[0013] In addition, when viewed in a cross-section including the axis, the vibration plate may have a portion extending from the first bend portion toward the axis having a constant curvature, and the outer edge of the vibration plate may be located on a virtual circle formed by that portion.

[0014] A speaker device according to an embodiment of the present invention includes the above diaphragm. EXAMPLES

[0015] (First embodiment) 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.

[0016] The magnetic circuit 3 is, for example, an external magnet type magnetic circuit, and is configured with a ring-shaped magnet 31, a yoke 32, and a ring-shaped top plate 33. The yoke 32 is configured with a bottom plate 34 and a center pole 35 erected 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 overlapped on the bottom plate 34. The center pole 35 is inserted into the center of the top plate 33, and the magnet 31 is overlapped on the surface of the magnet 31 on the diaphragm 6 side. The "magnetic gap G" is the gap between the top plate 33 and the center pole 35. Such a magnetic circuit 3 cooperates with the voice coil 4 to vibrate the diaphragm 6.

[0017] As shown in Figs. 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 Figs. 3 to 5, the dashed line P indicates the axis of the diaphragm 6. In the plan view of Fig. 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.

[0018] In order to reduce weight, the diaphragm 6 of this example is made of a lightweight material with lower rigidity than conventional products. In order to compensate for the loss in rigidity caused by using a lightweight material, the following reinforcement structure is provided. That is, the diaphragm 6 has a recess 63 recessed on the opposite side to the sound output direction in a cross-sectional view including the axis P. The "sound output direction" is the direction opposite to the voice coil 4 along the axis P. In this example, the recess 63 is formed around the entire circumference of the diaphragm 6.

[0019] 6, the recess 63 includes a first bent portion 64 bent in a direction convex toward the sound output direction at the middle of the 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 the 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 the second bent portion 65. That is, the recess 63 is formed by bending at three points, the first bent portion 64, the second bent portion 65, and the third bent portion 66. In this specification, "bent" does not mean gently curved, but rather bent.

[0020] The "middle part of the diaphragm 6" is the vicinity of the center between the inner peripheral edge 61 and the outer peripheral edge 62, and is the part where the amplitude is particularly large in the resonant state in which the part vibrates. A first bent part 64 is formed at the location in the middle part where the amplitude in the resonant state is the largest.

[0021] The second bent portion 65 and the third bent portion 66 are formed in the vicinity of the outer peripheral edge 62. Therefore, the distance along the diaphragm 6 from the first bent portion 64 to the second bent portion 65 is formed to be greater than the distance along the diaphragm 6 from the second bent portion 65 to the outer peripheral edge 62 via the third bent portion 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 bent portion 64 to the second bent portion 65 is about 20 mm, the distance along the diaphragm 6 from the second bent portion 65 to the third bent portion 66 is about 1 to 2 mm, and the distance along the diaphragm 6 from the third bent portion 66 to the outer peripheral edge 62 is about 5 mm.

[0022] 6, in a cross-sectional view including the axis P, the diaphragm 6 has a portion extending from the first bent portion 64 toward the axis P (the inner peripheral edge 61 side) with 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.

[0023] That is, in the diaphragm 6 of this example, the portion from the middle part curved at a constant curvature to the outer periphery is bent at two points, a first bent part 64 and a second bent part 65, and the outer periphery 62 is returned to the base curve (two-dot chain line F) at a third bent part 66 to form a recess 63. In this way, it is possible to reduce the weight of the diaphragm 6 and increase its rigidity with almost no change in the design or layout of the speaker device.

[0024] The edge 7 is formed in an annular shape in a plan view. In addition, the edge 7 is integrally configured to have an edge main body 71 formed in a convex arc shape in the sound output direction in a cross-sectional view shown in FIG. 2, an edge inner peripheral portion 72 continuing to the inner peripheral edge of the edge main body 71, and an edge outer peripheral portion 73 continuing to the outer peripheral edge of the edge main body 71. The edge inner peripheral portion 72 is bonded to a portion of the diaphragm 6 that is closer to the outer periphery than the third bent portion 66. The edge outer peripheral portion 73 is attached to the frame 2.

[0025] 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. This damper 8 allows the voice coil bobbin 5 and the diaphragm 6 to vibrate, while gradually damping these vibrations.

[0026] 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.

[0027] FIG. 7 is a table showing the stiffness change of the diaphragm 6 of the present invention (present invention product 1), a conventional diaphragm, and a comparative example diaphragm. The conventional diaphragm is a diaphragm having the shape shown in FIG. 1, and is a diaphragm having a shape obtained by removing the recess 63 from the diaphragm 6 of the present invention (a shape along the two-dot chain line F in FIG. 6). The conventional diaphragm is made of a standard material. The comparative example 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 a stiffness value (unit: [N / mm]) when the inner periphery of the diaphragm is fixed and a predetermined external force is applied to the outer periphery.

[0028] 7, it can be seen that the comparative example using a lightweight material has lower stiffness than the conventional product, but the product 1 of the present invention (diaphragm 6) using a lightweight material and forming the recess 63 has a stiffness that exceeds that of the conventional product. In other words, the product 1 of the present invention (diaphragm 6) is lighter in weight than the conventional product and has a stiffer stiffness than the conventional product.

[0029] 8 is a graph showing 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.

[0030] 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, and the rigidity of the outer periphery side of the present invention 1 (diaphragm 6) is strengthened.

[0031] 8, it can be seen that the peak around 4 kHz where the amplitude of the resonant state of the middle part of the diaphragm becomes large is changed to a dispersed shape (flattened) in the present invention 1 (diaphragm 6) as compared to the comparative example. In other words, the frequency characteristics of the present invention 1 (diaphragm 6) as a speaker are better than those of the comparative example. This is due to the first bent portion 64 being formed in the middle part of the diaphragm 6.

[0032] In addition, since the shape of the recess 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 recess 63 of the diaphragm 6 of the present invention is formed on the inner periphery side of the portion to which the inner periphery edge portion 72 is bonded (the portion on the outer periphery side of the third bent portion 66), the operation of bonding the inner periphery edge portion 72 to the diaphragm 6 can be easily performed.

[0033] (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-mentioned embodiment are given the same reference numerals and the description thereof will be omitted. The diaphragm 106 of this embodiment also constitutes a speaker device in the same manner as the first embodiment.

[0034] As shown in Figs. 9 to 11, the 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. The diaphragm 106 of this example is formed of a lightweight material to reduce weight. In order to compensate for the loss of rigidity caused by using a lightweight material, the following reinforcement structure is provided. That is, the diaphragm 106 is formed with a recess 163 recessed on the opposite side to the sound output direction in a cross-sectional view including the axis P. In this example, the recess 163 is formed around the entire circumference of the diaphragm 106.

[0035] 12, the recess 163 includes a first bent portion 64 bent in a direction convex toward the sound output direction at the middle portion of the 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 the first bent portion 64, and the outer periphery 62 of the diaphragm 106. That is, the recess 163 is formed by bending at two points, the first bent portion 64 and the second bent portion 65.

[0036] The second bent portion 65 is formed in the vicinity of the outer circumferential 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 circumferential edge 62.

[0037] 12, in a cross-sectional view including the axis P, the portion of the diaphragm 106 extending from the first bent portion 64 toward the axis P (the inner peripheral edge 61 side) has a constant curvature, and the portion from the first bent portion 64 to the second bent portion 65 and the portion from the second bent portion 65 to the outer peripheral edge 62 have the same curvature as the portion extending from the first bent portion 64 toward the axis P side. Furthermore, the outer peripheral edge 62 of the diaphragm 106 is located on an imaginary circle formed by the portion extending from the first bent portion 64 toward the axis P side. The two-dot chain line F in FIG. 12 indicates a part of the imaginary circle.

[0038] That is, the book diaphragm 106 is bent at a first bend 64 from the middle part curved at a constant curvature to the outer periphery, and then bent at a second bend 65 so as to return the outer periphery 62 to the base curve (two-dot chain line F) to form a recess 163. In this example, an edge is bonded to the part on the outer periphery side of the second bend 65. In this way, it is possible to reduce the weight of the diaphragm 106 and increase its rigidity with almost no change to the design or layout of the speaker device.

[0039] As in the first embodiment, the diaphragm 106 of this example is lighter in weight than the conventional product and has higher rigidity than the conventional product. In addition, since the shape of the recess 163 is simple, the weight increase can be suppressed and the mold for the diaphragm 106 can be easily manufactured.

[0040] (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-mentioned embodiments are given the same reference numerals and the description thereof will be omitted. The diaphragm 206 of this embodiment also constitutes a speaker device in the same manner as the first embodiment.

[0041] As shown in Figs. 13 to 15, the 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. The diaphragm 206 of this example is formed of a lightweight material to reduce weight. In order to compensate for the loss of rigidity caused by using a lightweight material, the following reinforcing structure is provided. That is, the diaphragm 206 is formed with a recess 263 recessed on the opposite side to the sound output direction in a cross-sectional view including the axis P.

[0042] In the first and second embodiments, the recesses 63, 163 are formed all around the periphery of the diaphragm, but in this embodiment, a portion 267 in the circumferential direction of the diaphragm 206 is left in a rib shape rather than being made into a recess 263. In this embodiment, this rib-shaped portion 267 is formed in five places, and five recesses 263 are formed in the circumferential direction of the diaphragm 206.

[0043] 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. Moreover, 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 is along the two-dot chain line F in Fig. 6. Moreover, the rib-like portion 267 is formed to have a uniform thickness.

[0044] (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-mentioned embodiments are given the same reference numerals and the description thereof will be omitted. The diaphragm 306 of this embodiment also constitutes a speaker device in the same manner as the first embodiment.

[0045] As shown in Figs. 16 to 18, the 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. The diaphragm 306 of this example is formed of a lightweight material to reduce weight. In order to compensate for the loss of rigidity caused by using a lightweight material, the following reinforcing structure is provided. That is, the diaphragm 306 has a recess 363 recessed on the side opposite to the sound output direction in a cross-sectional view including the axis P.

[0046] In this example, similar to the third embodiment, a portion 367 in the circumferential direction of the diaphragm 306 is left in a rib shape rather than being made into a recess 363. In this example, this rib-shaped portion 367 is formed in five places, and five recesses 363 are formed in the circumferential direction of the diaphragm 306. In addition, the rib-shaped portion 367 is formed to have a smaller width than the rib-shaped portion 267 in the third embodiment.

[0047] Each recess 363 has the same shape as the recess 263 of the third embodiment in a cross-sectional view 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. Also, the rib-like portion 367 is formed so that the thickness gradually increases from the inner periphery toward the outer periphery in a cross-sectional view including the axis P in Fig. 18.

[0048] The diaphragms of the above-mentioned Examples 1 to 4 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.

[0049] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention 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 is no particular contradiction or problem in the purpose and configuration. In addition, the contents of each figure can be independent embodiments, and the embodiment of the present invention is not limited to one embodiment obtained by combining each figure. [Explanation of symbols]

[0050] 1. Speaker device 6,106,206,306 Vibration plate 61 Inner edge 62 Outer rim 63,163,263,363 recess 64 1st bending part 65 2nd bending part 66 3rd bending part

Claims

1. A cone-shaped speaker diaphragm having a defined axis and an outer periphery, In a cross-sectional view including the axis, a recess 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 on the outer periphery side of the first bent portion, and a third bent portion bent in a direction convex toward the sound output direction on the outer periphery side of the second bent portion, a distance along the diaphragm from the first bent portion to the second bent portion is greater than a distance along the diaphragm from the second bent portion to an outer periphery of the diaphragm, In a cross-sectional view including the axis, a portion extending from the first bent portion toward the axis has a constant curvature, and an outer circumferential edge of the diaphragm is positioned on a virtual circle formed by the portion. A diaphragm characterized by:

2. The recess is formed around the entire periphery of the diaphragm. The diaphragm according to claim 1 .

3. In a cross-sectional view including the axis, a portion extending from the first bent portion toward the axis has a constant curvature, and a portion from the first bent portion to the second bent portion has a curvature equal to that of the portion extending from the first bent portion toward the axis.

3. The diaphragm according to claim 1 or 2.

4. A speaker device comprising the diaphragm according to any one of claims 1 to 3.

Images