Acoustic apparatus

Abstract

An acoustic apparatus (10) comprises: a speaker unit (30) that generates sound by vibrating a diaphragm; and a case (12) that houses the speaker unit (30). The case (12) is provided with a conical section (51) that is disposed facing the diaphragm (44) and protruded toward the diaphragm (44) side. A plurality of through holes (50A) that penetrate in the vibration direction of the diaphragm (44) are radially formed in the conical section (51).

Description

sound equipment

[0001] The present disclosure relates to acoustic devices.

[0002] Japanese Patent No. 7126763 discloses a car speaker case that includes a magnetic circuit, a coil, and a diaphragm, and a cover structure that is integrally formed with the case. In the car speaker of Japanese Patent No. 7126763, the cover structure is made up of a front cover and a rear cover separated by a space, and the front cover has a convex portion and a concave portion.

[0003] Meanwhile, acoustic devices such as in-vehicle speakers are required to be thinner due to constraints on installation dimensions, etc. The speaker described in Japanese Patent No. 7126763 does not take into consideration how to achieve a thinner design while maintaining acoustic performance, and there is room for improvement.

[0004] An object of the present disclosure is to provide an acoustic device that can be made thinner while maintaining acoustic performance.

[0005] The acoustic device of the first aspect has a speaker unit that generates sound by vibrating a diaphragm, and a case that houses the speaker unit, and the case has a conical portion that is arranged opposite the diaphragm and protrudes toward the diaphragm, and the conical portion has a plurality of through holes formed radially in the vibration direction of the diaphragm.

[0006] The above-described aspect includes a speaker unit that generates sound by vibrating a diaphragm, and the speaker unit is housed in a case. The case includes a conical portion disposed opposite the diaphragm, the conical portion protruding toward the diaphragm. This prevents the diaphragm from popping out, thereby preventing malfunctions due to sudden pressure changes. The conical portion also has a plurality of radially extending through-holes that penetrate the diaphragm in the vibration direction. This allows the length of the through-holes along the vibration direction of the diaphragm to be constant, even when the through-holes are formed in the conical portion, thereby enabling a thinner design while maintaining acoustic performance. Note that the term "conical portion" is not limited to a cone with a perfectly circular base, but broadly encompasses a cone with an elliptical base. It also includes a truncated cone configuration.

[0007] The acoustic device according to a second aspect is the acoustic device of the first aspect, wherein the conical portion is curved along the diaphragm.

[0008] In the above aspect, since the surface of the conical portion is curved along the diaphragm, the gap between the diaphragm and the conical portion can be kept substantially constant in the radial direction, and changes in acoustic characteristics can be adjusted.

[0009] The acoustic device according to a third aspect is the acoustic device of the first or second aspect, wherein the plurality of through holes are each arranged around a central axis of the conical portion.

[0010] In the above aspect, by arranging the through holes around the central axis of the conical portion, it is possible to suppress changes in acoustic characteristics compared to a structure in which the through holes are formed at random positions.

[0011] The acoustic device according to a fourth aspect is the acoustic device of any one of the first to third aspects, wherein the holes of adjacent through holes are connected to each other by a rib.

[0012] In the above aspect, by connecting the edges of the through holes with the ribs, the through holes can be reinforced while other portions can be hollowed out, thereby reducing costs and weight.

[0013] The acoustic device according to the fifth aspect is any one of the first to fourth aspects, and is provided with an outer cover outside the conical portion, and a plurality of outer through holes are formed radially in the outer cover.

[0014] In the above embodiment, the acoustic characteristics can be adjusted to any desired characteristics by changing the space between the conical portion and the outer cover.

[0015] The acoustic device according to a sixth aspect is the fifth aspect, wherein the outer through-hole is formed at a position different from the through-hole when viewed in the vibration direction of the diaphragm.

[0016] In the above aspect, the outer through-hole of the lid portion and the through-hole of the conical portion are formed at different positions, so that foreign matter can be prevented from entering the through-hole from the lid portion.

[0017] According to the acoustic device according to the present disclosure, it is possible to achieve a thinner design while maintaining acoustic performance.

[0018] FIG. 1 is a perspective view showing an acoustic device according to an embodiment; FIG. 2 is a side cross-sectional view showing a state cut along line 2-2 in FIG. 1; FIG. 3 is a plan cross-sectional view showing a state cut along line 3-3 in FIG. 2; FIG. 3 is a perspective view showing the main parts of FIG. 3; FIG. 4 is a cross-sectional perspective view showing the main parts of the inner cover and outer cover with some parts cut away; FIG. 5 is a cross-sectional perspective view corresponding to FIG. 6 of an acoustic device according to a modified example.

[0019] An acoustic device 10 according to an embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing the acoustic device 10 according to the embodiment. The acoustic device 10 according to the embodiment is mounted on a vehicle, for example, and can be used as an external sound system (ESS) such as a warning horn or an acoustic vehicle alerting system (AVAS). One side of the central axis of the acoustic device 10 is referred to as the one axial side (upper side), and the other side of the central axis is referred to as the other axial side (lower side). Furthermore, in a direction perpendicular to the central axis, the side closer to the central axis is referred to as the radially inner side, and the side farther from the central axis is referred to as the radially outer side. Note that the top and bottom of the acoustic device 10 are set for convenience of explanation and do not necessarily coincide with the top and bottom when the acoustic device 10 is mounted on a vehicle.

[0020] As shown in FIG. 1, an acoustic device 10 of this embodiment includes a case 12 that forms the outer shell of the device, and the case 12 includes a main baffle 14 and a lid 16. FIG. 2 is a side cross-sectional view taken along line 2-2 in FIG. 1. As shown in FIG. 2, the main baffle 14 is formed in the shape of a cylinder with a bottom that is open at the top, and is made of resin. Furthermore, a plurality of ribs 14A are formed on the bottom surface of the main baffle 14. In this embodiment, as an example, the ribs 14A are formed in a substantially lattice pattern. Furthermore, the opening of the main baffle 14 is closed by the lid 16.

[0021] The lid portion 16 is formed of resin and has a cylindrical shape with a bottom and an open bottom. Furthermore, as shown in FIG. 1 , the lid portion 16 is provided with three mounting pieces 18. Each of the mounting pieces 18 extends radially outward from the outer circumferential surface of the lid portion 16. In this embodiment, as an example, the mounting pieces 18 are provided at equal intervals around the periphery of the lid portion 16, and each mounting piece 18 has a through-hole 18A that penetrates in the vertical direction. Fasteners such as bolts are inserted into these through-holes 18A to attach the acoustic device 10 to a mounting member on the vehicle body side. Furthermore, the lid portion 16 is provided with a connector 20 for electrically connecting the acoustic device 10 to the outside.

[0022] 2, the lid 16 includes an inner cover 50 located on the lower side (inside) and an outer cover 52 located on the upper side (outside). The lid 16 will be described in detail later.

[0023] The case 12 houses a speaker unit 30 that generates sound by vibrating a diaphragm 44 .

[0024] The speaker unit 30 is composed of a frame 32, a magnetic circuit section 33 supported by the frame 32, a bobbin 40 arranged within the frame 32 and around which a voice coil is wound, a damper 42 provided between the bobbin 40 and the frame 32, a diaphragm 44 fixed to the bobbin 40, and an edge member 46 connecting the diaphragm 44 to the frame 32.

[0025] The frame 32 is formed in a generally stepped cylindrical shape, with one axial side (upper side) having a larger opening than the other axial side (lower side). The upper opening of the frame 32 is closed by a diaphragm 44 and an edge member 46, which will be described later.

[0026] The magnetic circuit section 33 includes a yoke 34 formed in a cylindrical shape with a bottom, a disk-shaped magnet 36 fixed to the bottom surface of the yoke 34, and a disk-shaped top plate 38 stacked on the magnet 36. The yoke 34 and the top plate 38 are made of a soft magnetic material, and the yoke 34 opens upward and is provided so as to close the opening on the lower side of the frame 32. A gap is formed between the top plate 38 and the yoke 34, and the bobbin 40 and part of the voice coil are arranged in this gap.

[0027] The voice coil is composed of a conductor wound around the outer periphery of a cylindrically formed bobbin 40. Although the voice coil is not shown in Fig. 2 to avoid cluttering the drawing, the voice coil is provided at the lower end of the bobbin 40 so as to be positioned in the magnetic gap. A diaphragm 44 is fixed to the upper end of the bobbin 40. The ends of the conductor wound around the bobbin 40 are each connected to terminals (not shown), and power is supplied to the voice coil from a power source external to the acoustic device 10 via the terminals.

[0028] The damper 42 is formed in a disk shape with an opening in the radial center when viewed from the axial direction. Furthermore, the cross section of the damper 42 when viewed from the radial direction has a corrugated shape with repeated curves in the up and down direction. The bobbin 40 is inserted into the opening formed in the center of the damper 42, and the inner peripheral end of the damper 42 is joined to the bobbin 40. The outer peripheral end of the damper 42 is joined to the frame 32. Thus, the bobbin 40 and the frame 32 are connected via the damper 42.

[0029] The diaphragm 44 is formed in a substantially circular shape when viewed in the axial direction, and is formed in a thin plate shape from, for example, an elastically deformable material. The diaphragm 44 is also curved so that the center portion is convex downward when viewed in the radial direction.

[0030] The edge member 46 is made of an elastic material such as rubber and has an annular shape when viewed in the axial direction. The edge member 46 has a curved cross-sectional shape that is convex downward when viewed in the radial direction, and the radially outer end of the edge member 46 is joined to the upper end of the frame 32. The radially inner end of the edge member 46 is joined to the upper surface of the outer peripheral end of the diaphragm 44 in a state where it overlaps the upper surface.

[0031] The speaker unit 30 is configured as described above, and when power is supplied to the voice coil and a current flows through the voice coil, the bobbin 40 moves back and forth in the axial direction (up and down). The back and forth movement of the bobbin 40 causes the diaphragm 44 to move back and forth in the axial direction, vibrating the diaphragm 44 and generating sound.

[0032] (Configuration of the lid portion 16) Next, the configuration of the lid portion 16 will be described.

[0033] The inner cover 50 constituting the lid portion 16 is disposed opposite the diaphragm 44 and includes a conical portion 51 that protrudes toward the diaphragm 44. That is, the conical portion 51 is formed to protrude downward, and the lower surface of the conical portion 51 is curved along the diaphragm 44 so that the downward side is convex, similar to the diaphragm 44, with a gap between the conical portion 51 and the diaphragm 44. Here, the conical portion 51 is formed with a plurality of inner through-holes 50A that radiate and penetrate in the vibration direction of the diaphragm 44.

[0034] Fig. 3 is a plan cross-sectional view taken along line 3-3 in Fig. 2. As shown in Fig. 3, the inner cover 50 has a plurality of inner through-holes 50A formed radially around the central axis of the conical portion 51.

[0035] In this embodiment, as an example, seven inner through-holes 50A are formed at approximately equal intervals around the central axis of the conical portion 51. The seven inner through-holes 50A are each formed to have approximately the same length in the radial direction, with their inner ends located near the center of the conical portion 51 and their outer ends located near the outer peripheral end of the conical portion 51.

[0036] Here, the edges of adjacent inner through holes 50A are connected by ribs 54. The ribs 54 are formed to connect adjacent inner through holes 50A in a generally arc shape, and seven ribs 54 are formed around the central axis of the conical portion 51. Note that a configuration without the ribs 54 may also be employed.

[0037] Fig. 4 is a perspective view showing the main parts of Fig. 3. As shown in Fig. 4, the inner cover 50 is formed with recesses 58 that are recessed around the inner through-holes 50A relative to the outer edges of the inner through-holes 50A. The recesses 58 form the upper surface of the conical portion 51 and are gradually inclined downward toward the central axis of the conical portion 51. As a result, the ribs 54 connecting the inner through-holes 50A protrude upward from the inclined surface that forms the recesses 58. Furthermore, because the edges of the inner through-holes 50A are formed at the same height as the ribs 54, the edges of the inner through-holes 50A are also formed to protrude upward from the inclined surface.

[0038] A flat region is formed radially outward of the recess 58 in the inner cover 50, and a plurality of drain holes 56 are formed in this region. As shown in Fig. 3, in this embodiment, as an example, 24 drain holes 56 are formed at approximately equal intervals around the central axis of the conical portion 51. Each drain hole 56 is formed in an approximately circular shape with a smaller diameter than the inner through-hole 50A, and penetrates the inner cover 50 in the thickness direction (see Fig. 2).

[0039] The rib 54 and the upper end of the inner through-hole 50A are formed at approximately the same height as the flat area in which the drainage holes 56 are formed. Therefore, the vertical depth of the inner through-hole 50A gradually increases toward the central axis. In other words, the inner through-hole 50A is configured so that its depth varies in the radial direction.

[0040] Fig. 5 is a plan view of the main parts of the acoustic device 10. Fig. 6 is a cross-sectional perspective view, with a portion cut away, showing the main parts of the inner cover 50 and the outer cover 52. As shown in Figs. 5 and 6, the outer cover 52 constituting the lid portion 16 is located above (outside of) the conical portion 51 and covers the inner cover 50 from the outside, and multiple outer through-holes 22, 24, and 26 are formed in the outer cover 52. Here, the outer through-holes 22, 24, and 26 are all formed at positions different from the inner through-hole 50A of the inner cover 50 when viewed in the vibration direction of the diaphragm 44 (in a plan view).

[0041] The outer through holes 22 are formed on the outer periphery of the outer cover 52, and are arranged radially at approximately equal intervals around the central axis. In the present embodiment, as an example, 24 outer through holes 22 are formed around the central axis. Each outer through hole 22 has a shorter radial length than the inner through hole 50A and a wider width than the inner through hole 50A. Furthermore, the outer through holes 22 are formed closer to the outer periphery than the inner through hole 50A.

[0042] The outer through holes 24 are formed more inwardly than the outer through holes 22. A plurality of outer through holes 24 are formed radially at approximately equal intervals around the central axis. In the present embodiment, as an example, fourteen outer through holes 24 are formed around the central axis. Each outer through hole 24 has a shorter radial length than the inner through hole 50A and a wider width than the inner through hole 50A. The outer opening edge of the outer through hole 24 is located radially outward from the outer opening edge of the inner through hole 50A, and the inner opening edge of the outer through hole 24 is located radially inward from the outer opening edge of the inner through hole 50A.

[0043] The outer through holes 26 are formed on the inner peripheral side of the outer through holes 22. Furthermore, multiple outer through holes 26 are formed radially at approximately equal intervals around the central axis. In the present embodiment, as an example, seven outer through holes 26 are formed around the central axis. Each outer through hole 24 is formed wider than the inner through holes 50A and is disposed between adjacent inner through holes 50A in a plan view. Furthermore, the opening edge of the inner end of the outer through hole 26 is located outward from the opening edge of the inner end of the inner through hole 50A. In other words, the inner end of the inner through hole 50A is located more inward than the inner end of the outer through hole 26.

[0044] In this way, the outer through holes 22, 24, 26 are arranged at positions that do not overlap with the inner through holes 50A in a plan view. The total opening area of ​​the outer through holes 22, 24, 26 is larger than the total opening area of ​​the inner through holes 50A. Furthermore, the number of outer through holes 22, 24, 26 is greater than the number of inner through holes 50A.

[0045] In this embodiment, the width of the hole wall of each of the inner through-hole 50A and the outer through-holes 22, 24, and 26 is the same from one end to the other, as shown in Fig. 6, but this is not limited thereto, and the width of the hole wall may be varied. For example, as shown in Fig. 7, the hole wall may be formed in a tapered shape.

[0046] Fig. 7 is a cross-sectional perspective view of an acoustic device according to a modified example, corresponding to Fig. 6. As shown in Fig. 7, the inner through-hole 50A formed in the inner cover 50 narrows from the lower side (inside) to the upper side (outside).

[0047] Furthermore, the outer through-hole 26 formed in the outer cover 52 narrows from the upper side (outside) to the lower side (inside). This increases the distance between the openings of the inner cover 50 and the outer cover 52 in the space between them, effectively preventing foreign matter from entering through the inner cover 50. Note that, although only the outer through-hole 26 is tapered in this modification, the present invention is not limited to this, and the outer through-holes 22, 24 may also be tapered so as to narrow from the upper side to the lower side.

[0048] (Operation) Next, the operation of this embodiment will be described.

[0049] 2, the acoustic device 10 of this embodiment includes a speaker unit 30 that generates sound by vibrating a diaphragm 44, and the speaker unit 30 is housed in a case 12. Here, an inner cover 50 of the case 12 includes a conical portion 51 disposed opposite the diaphragm 44, and the conical portion 51 protrudes toward the diaphragm 44. This allows the conical portion 51 to prevent the diaphragm 44 from popping out while the acoustic device 10 is in operation, thereby preventing malfunctions due to sudden pressure changes.

[0050] In addition, in this embodiment, the surface of the conical portion 51 is curved along the diaphragm 44, so the gap between the diaphragm 44 and the conical portion 51 can be kept substantially constant in the radial direction, making it possible to adjust the acoustic characteristics. Furthermore, in this embodiment, the acoustic characteristics can be adjusted by changing the space between the conical portion 51 and the outer cover 52.

[0051] 3, in this embodiment, a plurality of inner through-holes 50A are radially formed in the conical portion 51, penetrating in the vibration direction of the diaphragm 44. As a result, even when the inner through-holes 50A are formed in the conical portion 51, the length of the inner through-holes 50A along the vibration direction of the diaphragm 44 can be made constant, making it possible to achieve a thinner design while maintaining acoustic performance. As a result, the acoustic device 10 of this embodiment can be made thinner while maintaining acoustic performance.

[0052] Furthermore, in this embodiment, by arranging the inner through holes 50A around the central axis of the conical portion 51, changes in acoustic characteristics can be suppressed compared to a structure in which the inner through holes 50A are formed in scattered positions.

[0053] Furthermore, in this embodiment, the edges of the inner through-holes 50A are connected by the ribs 54, which allows the inner through-holes 50A to be reinforced while other portions are hollowed out, thereby reducing costs and weight.

[0054] In particular, in this embodiment, the inner cover 50 is formed with a recess 58 that is recessed around the inner through-hole 50A more deeply than the outer edge of the inner through-hole 50A, thereby enabling cost and weight reduction compared to a structure without a recess.

[0055] Furthermore, as shown in FIG. 5, in this embodiment, the outer through-holes 22, 24, 26 formed in the outer cover 52 and the inner through-hole 50A formed in the conical portion 51 are formed in different positions, thereby preventing foreign matter from entering the speaker unit 30 from the case 12.

[0056] In particular, in this embodiment, the outer through holes 22, 24, 26 are formed at positions different from the inner through hole 50A in a plan view, and therefore, it is possible to effectively prevent the intrusion of foreign matter regardless of the shapes and sizes of the inner through hole 50A and the outer through holes 22, 24, 26. In other words, even if a foreign matter intrudes into the outer through holes 22, 24, 26 from the outside, it can be prevented from passing through the inner through hole 50A.

[0057] Furthermore, in this embodiment, the total opening area of ​​the outer through holes 22, 24, and 26 is larger than the total opening area of ​​the inner through hole 50A, so that the sound generated by the vibration of the diaphragm 44 can be prevented from reverberating between the inner cover 50 and the outer cover 52.

[0058] In addition, in this embodiment, the outer through holes 22, 24, 26 are formed wider than the inner through hole 50A, so sound can be effectively output to the outside without increasing the number of outer through holes. In this way, this embodiment provides a structure with a high degree of design freedom while suppressing the intrusion of foreign matter.

[0059] [Supplementary Explanation] The acoustic device 10 according to the embodiment and the modified examples has been described above, but it goes without saying that it can be embodied in various forms without departing from the spirit of the present invention. For example, in the above embodiment, the entire case 12 is formed in a substantially cylindrical shape as shown in Fig. 1, but this is not limited thereto and the case may be formed in another shape. For example, the case 12 may be formed in a substantially rectangular tube shape.

[0060] Furthermore, in the above embodiment, the acoustic device 10 is described as being mounted on a vehicle, but the present invention is not limited to this, and the acoustic device 10 may be applied to other locations. In particular, if the acoustic device 10 of this embodiment is applied to outdoor equipment that is susceptible to the effects of foreign matter and water, it is possible to maintain acoustic performance while suppressing the intrusion of foreign matter, but the acoustic device 10 may also be applied to indoor equipment.

[0061] Furthermore, in the above embodiment, a structure in which multiple outer through holes 22, 24, 26 of different shapes are formed is described, but this is not limited thereto. For example, a structure in which only some of the outer through holes 22, 24, 26 are formed may also be used. Furthermore, the layout of the outer through holes 22, 24, 26 may be changed as appropriate. The disclosure of Japanese Patent Application No. 2023-140442 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference.

Claims

1. An acoustic device comprising: a speaker unit that generates sound by vibrating a diaphragm; and a case that houses the speaker unit, wherein the case is provided with a conical portion that is disposed opposite the diaphragm and protrudes toward the diaphragm, and the conical portion has a plurality of radially-spaced through holes that penetrate in the direction of vibration of the diaphragm.

2. The acoustic device according to claim 1, wherein said conical portion is curved along said diaphragm.

3. The acoustic device according to claim 1, wherein the plurality of through holes are each arranged around the central axis of the conical portion.

4. The acoustic device according to claim 1, wherein the edges of the adjacent through holes are connected by a rib.

5. An acoustic device as claimed in any one of claims 1 to 4, further comprising an outer cover disposed outside said conical portion, said outer cover having a plurality of outer through holes formed radially therein.

6. The acoustic device according to claim 5, wherein the outer through-hole is formed at a position different from the through-hole when viewed in the vibration direction of the diaphragm.

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