Acoustic device

Abstract

According to the present invention, the acoustic performance of an acoustic device including a diaphragm and a protective member disposed on the front surface side of the diaphragm is improved. An acoustic device 10 includes a special protective member 14 that is disposed on the front surface side of a diaphragm 27 to protect the diaphragm 27. The special protective member 14 has a plurality of through-holes 42 that penetrate through in a device front-rear direction, and the plurality of through-holes 42 include special holes 42. The special holes 42 are holes having a shape in which a part of the edge of the hole is not visible when viewed from the position of the centroid.

Description

Acoustic device

[0001] The present disclosure relates to an acoustic device.

[0002] Patent Document 1 discloses an acoustic device including a diaphragm and a protective member disposed on the front side of the diaphragm.

[0003] Japanese Patent Application Laid-Open No. 2011-142502

[0004] An object of the present disclosure is to improve acoustic performance in an acoustic device including a diaphragm and a protective member disposed on the front side of the diaphragm.

[0005] The acoustic device according to the first aspect includes a diaphragm that generates sound by vibrating, and at least one protective member that protects the diaphragm by being disposed on the front side of the diaphragm. The at least one protective member includes a special protective member, and the special protective member has a plurality of through holes penetrating in the front-rear direction of the device. The plurality of through holes include special holes having a shape in which a part of the edge is not visible when viewed from the centroid position.

[0006] In this aspect, the acoustic device includes a diaphragm that generates sound by vibrating and at least one protective member. The protective member protects the diaphragm by being disposed on the front side of the diaphragm.

[0007] Here, in this aspect, the at least one protective member includes a special protective member. The special protective member has a plurality of through holes penetrating in the front-rear direction of the device, and the plurality of through holes are protective members including special holes. The special hole refers to a hole having a shape in which a part of the edge is not visible when viewed from the centroid position. Therefore, the balance of the surface tension at the edge of the special hole is easily disrupted, and it is difficult for a water film to form on the special hole. If a water film forms on the through hole, the sound pressure in the desired band may be significantly reduced. Therefore, by including special holes in the plurality of through holes, this can be suppressed.

[0008] From the above, according to this aspect, the acoustic performance can be improved.

[0009] Furthermore, "a shape in which part of the edge is not visible when viewed from the centroid" means, in other words, a hole in which, if the edge of the hole is observed with respect to the centroid of the hole, part of the edge of the hole is hidden from view by another part of the edge of the hole. For example, in a through hole 32 having the shape shown in Figure 13, even if one tries to see the edge 32K of the hole from its centroid, the other edge 32L obstructs the view, making it impossible to see the edge 32K. A through hole having such a shape is a special hole. In the embodiments described later, at least one protective member includes two protective members, and both of these two protective members have a special hole. However, this embodiment is not limited to this. For example, at least one protective member may consist of one protective member. Also, for example, when at least one protective member consists of two protective members, one of the protective members does not have to have a special hole. In the embodiments described later, the shape of the special hole includes a portion that forms a T-shaped hole. However, the special hole in this embodiment is not limited to this. The shape of the special hole may be, for example, an L-shaped shape. In the description of the embodiments described later, there are parts where the front cover is described as corresponding to a special protective member, but it can also be considered that the protector corresponds to a special protective member.

[0010] The acoustic device according to the second embodiment, in the first embodiment, has a special hole comprising a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction. The radial direction refers to the direction perpendicular to the central axis of the acoustic device. The circumferential direction refers to the direction circumferential to the central axis of the acoustic device.

[0011] In the third embodiment of the acoustic device, in the second embodiment, the circumferential elongated hole portion is provided in the outer region, and the radial elongated hole portion is provided in a region spanning the central region and the outer region.

[0012] According to this embodiment, a special hole can be configured as a composite hole including a through hole (circumferentially elongated hole) provided in the outer region. The "central region" refers to the area inside a circle or polygon drawn with a constant radius from the central axis when viewed from the axial direction of the sound device. The "outer region" refers to the area outside a circle or polygon drawn with a constant radius from the central axis when viewed from the axial direction of the sound device.

[0013] In the fourth embodiment of the acoustic device, in the second or third embodiment, the circumferential elongated hole and the radial elongated hole form portions that are T-shaped, Y-shaped, or arrow-shaped.

[0014] In the fifth embodiment of the acoustic device, in the second embodiment, the radially elongated hole is provided in the central region or in a region spanning the central region and the outer region, and the circumferentially elongated hole is provided in the central region.

[0015] In the sixth embodiment of the acoustic device, in the second or fifth embodiment, the circumferential elongated hole and the radial elongated hole form portions that have a cross-shaped hole.

[0016] The acoustic device according to the seventh embodiment, in any of the first to sixth embodiments, has a special hole comprising a first radially elongated hole portion extending along the radial direction, a pair of second radially elongated holes extending along the radial direction, and an inner circumferentially elongated hole portion provided in the central region and extending along the circumferential direction, wherein the pair of second radially elongated holes are located on both sides in the circumferential direction relative to the first radially elongated hole portion, and the inner circumferentially elongated hole portion connects the first radially elongated hole portion and the pair of second radially elongated holes.

[0017] According to this embodiment, the shape of the special pores can be made more complex, and the surface area of ​​the water film can be increased, thereby increasing the mass of the water. As a result, the formation of a water film on the special pores can be further suppressed.

[0018] The acoustic device according to the eighth embodiment, in any of the first to seventh embodiments, has a special hole comprising a first radially elongated hole portion extending along the radial direction, a pair of second radially elongated holes extending along the radial direction, an inner circumferentially elongated hole portion provided in the central region and extending along the circumferential direction, and an outer circumferentially elongated hole portion provided in the outer region and extending along the circumferential direction, wherein the pair of second radially elongated holes are located on both sides in the circumferential direction with respect to the first radially elongated hole portion, the inner circumferentially elongated hole portion connects the first radially elongated hole portion and the pair of second radially elongated holes, and the first radially elongated hole portion and the outer circumferentially elongated hole portion are connected.

[0019] According to this embodiment, the shape of the special pores can be made more complex, and the surface area of ​​the water film can be increased, thereby increasing the mass of the water. As a result, the formation of a water film on the special pores can be further suppressed.

[0020] In the ninth embodiment of the acoustic device, in any of the first to eighth embodiments, a plurality of the special holes are provided, and the plurality of special holes are arranged along the circumferential direction.

[0021] The acoustic device according to the tenth embodiment, in any of the first to ninth embodiments, does not include through holes other than special holes whose shape is such that a portion of the edge is not visible when viewed from the centroid.

[0022] According to this embodiment, the formation of a water film in multiple through-holes can be suppressed. The term "through-holes" here refers to those related to acoustics. For example, through-holes that are blocked by other components are not related to acoustics and therefore do not fall under the definition of "through-holes" here.

[0023] The acoustic device according to the eleventh embodiment, in any of the first to tenth embodiments, includes an additional protective member, the additional protective member having a plurality of additional through holes penetrating in the front-to-back direction of the device, and the plurality of additional through holes are provided in positions that do not overlap with the plurality of through holes when viewed from the front side.

[0024] According to this embodiment, it is possible to prevent foreign objects such as pebbles from entering through both the through hole and the additional through hole.

[0025] The acoustic device according to the twelfth embodiment, in any of the first to tenth embodiments, includes an additional protective member, the additional protective member having a plurality of additional through holes penetrating in the front-to-back direction of the device, and the plurality of additional through holes including additional special holes with a shape in which a portion of the edge is not visible when viewed from the centroid.

[0026] According to this embodiment, the balance of surface tension at the edges of the additional special holes is easily disrupted, and the formation of a water film on the additional special holes can be suppressed.

[0027] The acoustic device according to the 13th embodiment, in the 12th embodiment, has an additional special hole comprising a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction, wherein the circumferentially elongated hole portion is provided in the outer region and the radially elongated hole portion is provided in a region spanning the central region and the outer region.

[0028] The acoustic device according to the 14th embodiment, in the first embodiment, the special hole has a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction, the circumferentially elongated hole portion is provided in the outer region, and the radially elongated hole portion is provided in a region spanning the central region and the outer region, the at least one protective member includes an additional protective member, the additional protective member has a plurality of additional through holes penetrating in the front-rear direction of the device, the plurality of additional through holes include an additional special hole with a shape in which a part of the edge is not visible when viewed from the centroid position, the additional special hole has a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction, the circumferentially elongated hole portion is provided in the outer region, and the radially elongated hole portion is provided in a region spanning the central region and the outer region.

[0029] According to this disclosure, in an acoustic device comprising a diaphragm and a protective member disposed on the front side of the diaphragm, the acoustic performance can be improved.

[0030] This is a cross-sectional view of the acoustic device (section 1-1 in Figure 2). This is a front view of the acoustic device. This is a rear view of the protector. This is a cross-sectional view of the protector (section 4-4 in Figure 3). This is a rear view of the front cover. This is a cross-sectional view of the front cover (section 6-6 in Figure 5). This is a perspective view of the protector from the front. This is a diagram showing a first modified example of multiple first through holes. This is a diagram showing a second modified example of multiple first through holes. This is a diagram showing a first modified example of multiple second through holes. This is a diagram showing a second modified example of multiple second through holes. This is a diagram showing a modified cross-sectional shape of a through hole. This is an explanatory diagram of the definition of a special hole.

[0031] The following describes the acoustic device 10 according to the embodiment of this disclosure.

[0032] The sound device 10 of this embodiment can be mounted on a vehicle as an example and used as an external sound system (ESS) such as a horn or an acoustic vehicle alerting system (AVAS). Hereinafter, when simply indicating the front and rear directions, it refers to the front and rear directions of the sound device 10 unless otherwise specified. The sound device 10 of this embodiment is mounted on the vehicle with its front side facing the direction of gravity.

[0033] As shown in Figure 1, the sound device 10 comprises a sound device body 11, a rear cover 12, a protector 13, a front cover 14, and a sealing member 15.

[0034] The main body of the acoustic device 11 comprises magnetic circuits 21, 22, 23, a frame 24, a damper 25, a voice coil 26, and diaphragm assemblies 27, 28.

[0035] The magnetic circuits 21, 22, and 23 each comprise a yoke 21 formed in the shape of a bottomed cylinder, a disc-shaped magnet 22, and a disc-shaped top plate 23.

[0036] The frame 24 comprises a frame body 24A and a cover portion 24B. The frame body 24A supports the magnetic circuits 21, 22, and 23. The frame body 24A is formed in a substantially stepped cylindrical shape, with the front side being a larger cylinder than the rear side. The cover portion 24B has a front wall portion 24B1 extending radially outward from the front end of the frame body 24A, and a side wall portion 24B2 extending towards the rear from the outer peripheral end of the front wall portion 24B1.

[0037] The damper 25 elastically supports the voice coil 26 so that it can be displaced in the front-rear direction. The inner circumference of the damper 25 is joined to the bobbin of the voice coil 26, and the outer circumference of the damper 25 is joined to the frame body 24A.

[0038] The diaphragm assemblies 27 and 28 are fixed to the front end of the voice coil 26. Each diaphragm assembly 27 and 28 has a diaphragm 27 and an edge 28. The diaphragm 27 is circular when viewed from the front-to-back direction and has a shape that is convex towards the rear. The edge 28 connects the diaphragm 27 to the frame body 24A. The edge 28 is made of an elastic material such as rubber and is formed in an annular shape when viewed from the front-to-back direction. The radially inner end of the edge 28 is joined to the radially outer end of the diaphragm 27 in a state where they overlap in the front-to-back direction.

[0039] In this disclosure, the central axis AX refers to the central axis AX of the acoustic device body 11. The front-rear direction refers to the direction parallel to the central axis. The radial direction refers to the direction perpendicular to the central axis AX. The circumferential direction refers to the circumferential direction with respect to the central axis AX.

[0040] The rear cover 12 is formed in a box shape with the front side open. The rear cover 12 is attached to the rear of the cover portion 24B of the frame 24. The joint between the rear cover 12 and the frame 24 is sealed, for example, with adhesive. This ensures watertightness at the joint between the rear cover 12 and the frame 24. As a result, waterproofing is ensured in the space on the rear side of the diaphragm assemblies 27 and 28.

[0041] The protector 13 is disposed on the front side with respect to the diaphragm assemblies 27 and 28 of the acoustic device main body 11, and protects the diaphragm assemblies 27 and 28 from the front side.

[0042] The front cover 14 is disposed on the front side with respect to the protector 13, and covers the protector 13 from the front side. Thereby, the front cover 14 protects the diaphragm assemblies 27 and 28 from the front side together with the protector 13. Hereinafter, the protector 13 and the front cover 14 may be referred to as the protection member 13 and the protection member 14.

[0043] The seal member 15 is formed of an elastic material such as rubber. The seal member 15 is formed in an annular shape so as to surround a region where a plurality of second through holes 42 (see FIG. 1) of the front cover 14 are provided. The seal member 15 is joined to the front surface of the front cover 14.

[0044] Next, the protector 13 and the front cover 14 will be described in more detail.

[0045] (Protector 13) As shown in FIG. 7, the protector 13 has a protector main body 31 whose thickness direction is generally in the front-rear direction. The protector main body 31 has a convex portion 31A that constitutes the central portion of the protector 13 and an outer peripheral flat plate portion 31B that constitutes the outer peripheral portion of the protector 13. In the present embodiment, when viewed from the front side, the region where the convex portion 31A of the protector 13 is provided is referred to as the central region (see FIG. 4). The central region is a circular region. Also, the region outside the central region is referred to as the outer region.

[0046] The convex portion 31A has a curved surface shape that protrudes toward the rear side. The rear surface 31A1 of the convex portion 31A is a curved surface having a shape along the front surface of the diaphragm assemblies 27 and 28. In other words, the convex portion 31A (central region portion) of the protector 13 has an inner inclined surface 31A1 that has a downward gradient from the rear to the front toward the outer side in the radial direction.

[0047] As shown in FIG. 7, the outer peripheral flat plate portion 31B has an annular shape that surrounds the outer periphery of the convex portion 31A when viewed from the front-rear direction, and has a substantially flat plate shape with the plate thickness direction in the front-rear direction.

[0048] As shown in FIG. 4, the rear surface 31B1 of the outer peripheral flat plate portion 31B slopes downward toward the radially inner side. In other words, the outer peripheral flat plate portion 31B (outer region portion) of the protector 13 has an outer inclined surface 31B1 that slopes downward toward the radially inner side.

[0049] As shown in FIG. 3, the protector 13 has a plurality (seven) of first through holes 32. The first through holes 32 penetrate the protector body 31 in the front-rear direction. Therefore, the space between the diaphragm 27 and the protector 13 and the plurality of first through holes 32 can create acoustic resonance and amplify sound of a specific frequency.

[0050] Each first through hole 32 is a hole formed by combining a radially long hole portion 33 and a circumferentially long hole portion 34. The first through holes 32 are arranged at equal intervals along the circumferential direction.

[0051] The radially long hole portion 33 extends along the radial direction. Specifically, the radially long hole portion 33 extends linearly parallel to the radial direction. The radially long hole portion 33 is provided in a region straddling the central region and the outer region. Specifically, the radially inner end of the radially long hole portion 33 is located in the central region, and the radially outer end of the radially long hole portion 33 is located in the outer region.

[0052] The circumferentially long hole portion 34 extends along the circumferential direction. Specifically, the circumferentially long hole portion 34 extends in an arc shape along the circumferential direction. The circumferentially long hole portion 34 is provided in the outer region. Specifically, the circumferentially long hole portion 34 is provided at a position close to the convex portion 31A in the outer peripheral flat plate portion 31B.

[0053] The circumferentially long hole portion 34 is connected to the radially outer end of the radially long hole portion 33. Specifically, the central portion in the length direction of the circumferentially long hole portion 34 is connected to the radially outer end of the radially long hole portion 33. Thereby, the radially long hole portion 33 and the circumferentially long hole portion 34 form a portion having a T-shaped hole shape.

[0054] As shown in Figure 13, in the through hole 32, for example, even if one tries to view the edge 32K of the hole from its centroidal position, the other edge 32L obstructs the view, making it impossible to see the edge 32K. Therefore, the through hole 32 can be described as a hole in which a part of the edge is not visible when viewed from the centroidal position. Hereinafter, the through hole 32 may be referred to as a special hole 32 or an additional special hole 32. A special hole means a hole in which a part of the edge is not visible when viewed from the centroidal position.

[0055] As shown in Figure 7, the protector 13 has a plurality of protrusions 35A, 35B, and 35C that protrude forward from the protector body 31.

[0056] Specifically, the protector 13 has a central projection 35A that protrudes forward from the center of the protector body 31. The central projection 35A is cylindrical in shape with its axial direction in the front-to-back direction.

[0057] Furthermore, the protector 13 has a plurality of elongated cylindrical portions 35B that protrude forward from the edges of the plurality of first through holes 32. The inner space of each elongated cylindrical portion 35B communicates with each of the first through holes 32. The front ends of the plurality of elongated cylindrical portions 35B are located on a plane perpendicular to the central axis AX. The radially inner ends of the plurality of elongated cylindrical portions 35B are connected to the central projection 35A via other projections (reference numerals omitted).

[0058] Furthermore, the protector 13 has a plurality of connecting protrusions 35C that connect adjacent elongated cylindrical portions 35B in the circumferential direction.

[0059] The protector 13 has a connecting cylindrical portion 36 that protrudes forward from the outer edge of the protector body 31.

[0060] (Front cover 14) As shown in Figure 6, the front cover 14 has a roughly disc-shaped front cover body 41.

[0061] As shown in Figure 5, the front cover 14 has a plurality (7) of second through holes 42. The second through holes 42 penetrate the front cover body 41 in the front-rear direction. The number of second through holes 42 is the same as the number of first through holes 32. The plurality of second through holes 42 are arranged at equal intervals along the circumferential direction.

[0062] The second through-hole 42 is a hole formed by combining a first radially elongated hole portion 43, an outer circumferentially elongated hole portion 44, a pair of second radially elongated hole portions 45, and an inner circumferentially elongated hole portion 46.

[0063] The first radially elongated hole portion 43 extends along the radial direction. Specifically, the first radially elongated hole portion 43 extends linearly parallel to the radial direction. The first radially elongated hole portion 43 is provided in a region that spans the central region and the outer region. Specifically, the radially inner end of the first radially elongated hole portion 43 is located in the central region, and the radially outer end of the first radially elongated hole portion 43 is located in the outer region.

[0064] The outer circumferential elongated hole portion 44 extends along the circumferential direction. Specifically, the outer circumferential elongated hole portion 44 extends in an arc shape along the circumferential direction. The outer circumferential elongated hole portion 44 is provided in the outer region. At its midpoint in the longitudinal direction, the outer circumferential elongated hole portion 44 is connected to the radially outer end of the first radial elongated hole portion 43. As a result, the outer circumferential elongated hole portion 44 and the first radial elongated hole portion 43 form a T-shaped hole. The outer circumferential elongated hole portion 44 is located radially outward from the circumferential elongated hole portion 34 of the protector 13.

[0065] Each second radial slot 45 extends along the radial direction. Specifically, each second radial slot 45 extends linearly parallel to the radial direction. A pair of second radial slots 45 are located on both sides of the first radial slot 43 in the circumferential direction. The second radial slots 45 are provided in the central region. The length of the second radial slot 45 is smaller than the length of the first radial slot 43.

[0066] The inner circumferential elongated hole portion 46 extends along the circumferential direction. Specifically, the inner circumferential elongated hole portion 46 extends in an arc shape along the circumferential direction. The inner circumferential elongated hole portion 46 is provided in the central region. The inner circumferential elongated hole portion 46 connects the first radial elongated hole portion 43 and a pair of second radial elongated hole portions 45. Specifically, the inner circumferential elongated hole portion 46 connects the longitudinal intermediate portion of one of the pair of second radial elongated hole portions 45 to the longitudinal intermediate portion of the other second radial elongated hole portion 45.

[0067] The second through-hole 42 is configured as described above, so that a portion of its edge is not visible when viewed from the centroid. Hereinafter, the second through-hole 42 may be referred to as the special hole 42 or the additional special hole 42.

[0068] The multiple second through-holes 42 are positioned so as not to overlap with the multiple first through-holes 32 when viewed from the front. Therefore, as shown in Figure 2, when the acoustic device 10 is viewed from the front, the diaphragm assemblies 27 and 28 are completely hidden by the protector 13 and the front cover 14.

[0069] As shown in Figure 5, the front cover 14 has an outer peripheral recess 41C. The outer peripheral recess 41C is a recess that is recessed toward the front and is located on the rear side of the front cover 14. The outer peripheral recess 41C extends in an annular shape. The outer peripheral recess 41C is located at a position corresponding to the position where the outer circumferential elongated hole 44 is provided. In other words, the radial position of the outer peripheral recess 41C coincides with the radial position of the outer circumferential elongated hole 44. Therefore, the outer peripheral recess 41C is divided at the position where the outer circumferential elongated hole 44 is provided.

[0070] The bottom surface of the outer peripheral recess 41C has a downward slope toward the outer circumferential elongated hole 44. Specifically, each divided outer peripheral recess 41C has a pair of inclined bottom surfaces 41C1 and 41C2. One inclined bottom surface 41C1 has a downward slope toward the outer circumferential elongated hole 44 located on one side of the outer peripheral recess 41C in the circumferential direction. The other inclined bottom surface 41C2 has a downward slope toward the outer circumferential elongated hole 44 located on the other side of the outer peripheral recess 41C in the circumferential direction. This downward slope is designed to allow water in the outer peripheral recess 41C to flow toward the outer circumferential elongated hole 44.

[0071] The front cover 14 has an inner inclined surface 41A and an outer inclined surface 41B as the rear surface of the front cover 14. The inner inclined surface 41A and the outer inclined surface 41B are the rear surfaces of the front cover body 41.

[0072] The inner inclined surface 41A is provided radially inward from the outer recess 41C. The inner inclined surface 41A has a downward slope toward the radial outward direction. The inner inclined surface 41A extends from the central engaging portion 41D (described later) to the outer recess 41C or the outer circumferential elongated hole portion 44. This downward slope is intended to direct water on the inner inclined surface 41A toward the outer recess 41C or the outer circumferential elongated hole portion 44.

[0073] The outer inclined surface 41B is provided radially outward from the outer peripheral recess 41C. The outer inclined surface 41B has a downward slope toward the radially inward. This downward slope is for directing water on the outer inclined surface 41B toward the outer peripheral recess 41C or the outer circumferential elongated hole 44, etc.

[0074] The front cover 14 has a central engaging portion 41D. The central engaging portion 41D of the front cover 14 engages with the central protrusion 35A of the protector 13.

[0075] The front cover 14 has an outer engaging portion 48. The outer engaging portion 48 is the part that is joined to the protector 13 and the frame 24. The outer engaging portion 48 has an inner cylindrical portion 48A and an outer cylindrical portion 48B that protrude rearward from the front cover body 41. The joining cylindrical portion 36 of the protector 13 is positioned between the inner cylindrical portion 48A and the outer cylindrical portion 48B.

[0076] (Modified form of the first through-hole 32) Figure 8 shows a plurality of first through-holes 132, which is a first modified form of the plurality of first through-holes 32.

[0077] Each first through-hole 132 is a hole formed by combining a radially elongated hole portion 133 and a circumferentially elongated hole portion 134. In the above embodiment, the circumferentially elongated hole portion 34 extends in an arc shape along the circumferential direction (see Figure 3), whereas the circumferentially elongated hole portion 134 of the first modified example is not configured in this way. Specifically, the circumferentially elongated hole portion 134 is composed of a first portion 134a and a second portion 134b that extend linearly in the circumferential direction and diagonally inward from the radially outer end of the radially elongated hole portion 133. As a result, the first through-hole 132 has a so-called arrow shape. In this disclosure, such a circumferentially elongated hole portion 134 is also referred to as a circumferentially elongated hole portion that extends along the circumferential direction.

[0078] Figure 9 shows a second modified example of the multiple first through holes 32, which is a plurality of first through holes 232.

[0079] Each first through-hole 232 is a hole formed by combining a radially elongated hole portion 233 and a circumferentially elongated hole portion 234. In the above embodiment, the circumferentially elongated hole portion 34 extends in an arc shape along the circumferential direction, whereas the circumferentially elongated hole portion 234 of the second modified example is not configured in this way. Specifically, the circumferentially elongated hole portion 234 is composed of a first portion 234a and a second portion 234b that extend linearly in the circumferential direction and diagonally outward from the radially outer end of the radially elongated hole portion 233. As a result, the first through-hole 232 has a Y-shape. In this disclosure, such a circumferentially elongated hole portion 234 is also referred to as a circumferentially elongated hole portion that extends along the circumferential direction.

[0080] (First modified example of the second through-hole 42) Figure 10 shows a plurality of second through-holes 142, which is a first modified example of the plurality of second through-holes 42.

[0081] Each second through-hole 142 is a hole formed by combining a first radial elongated hole portion 143, an outer circumferential elongated hole portion 144, a pair of second radial elongated hole portions 145, and an inner circumferential elongated hole portion 146. In the above embodiment, the outer circumferential elongated hole portion 44 extends in an arc shape along the circumferential direction (see Figure 5), whereas the outer circumferential elongated hole portion 144 of the first modified example is not configured in this way. Specifically, the outer circumferential elongated hole portion 144 is composed of a first portion 144a and a second portion 144b that extend linearly in the circumferential direction and diagonally inward in the radially outer end of the first radial elongated hole portion 143. As a result, the second through-hole 142 includes a portion having a so-called arrow shape. In this disclosure, such an outer circumferential elongated hole portion 144 is also referred to as a circumferential elongated hole portion that extends along the circumferential direction.

[0082] (Second modified example of the second through-hole 42) Figure 11 shows a plurality of second through-holes 242, which is a second modified example of the plurality of second through-holes 42.

[0083] Each second through-hole 242 is a hole formed by combining a first radial elongated hole portion 243, an outer circumferential elongated hole portion 244, a pair of second radial elongated hole portions 245, and an inner circumferential elongated hole portion 246. In the above embodiment, the outer circumferential elongated hole portion 44 extends in an arc shape along the circumferential direction, whereas the outer circumferential elongated hole portion 244 of the second modified example is not configured in this way. Specifically, the outer circumferential elongated hole portion 244 is composed of a first portion 244a and a second portion 244b that extend linearly in the circumferential direction and diagonally outward from the radially outer end of the first radial elongated hole portion 243. As a result, the second through-hole 242 includes a portion having a Y-shape. In this disclosure, such an outer circumferential elongated hole portion 244 is also referred to as a circumferential elongated hole portion that extends along the circumferential direction.

[0084] (Modified Cross-sectional Shape of Through Hole) Figure 12 is a cross-sectional view showing the cross-sectional shape of the second through hole 142 (see Figure 10), which is the first modified example. Specifically, it is a cross-sectional view (cross-sectional view along line 12-12 in Figure 10) showing the state when the first radially elongated hole portion 143, which is an elongated hole, is cut perpendicular to its longitudinal direction.

[0085] As shown in Figure 12, the second through-hole 142 is configured such that its size widens in the direction of gravity (towards the front of the device). In other words, the pair of inner wall surfaces 143a of the first radially elongated hole portion 143, which is an elongated hole, are inclined such that the width of the first radially elongated hole portion 143 widens in the direction of gravity (towards the front of the device). By configuring the cross-sectional shape of the second through-hole 142 in this way, it is difficult for a water film to form in the second through-hole 142, and the formation of a water film can be suppressed. This is because a water film that forms in such a second through-hole 142 becomes thinner as it moves in the direction of gravity, and as a result, it becomes more easily broken. It is preferable that the boundary portion (corner) between the pair of inner wall surfaces 143a and the front surface (the surface facing the direction of gravity) of the front cover 14 be formed in a fillet shape.

[0086] In Figure 12, the cross-sectional shape of the first radially elongated hole portion 143 of the second through-hole 142 is shown and explained as an example. However, for example, all of the second through-holes 42 in the front cover 14 may have this cross-sectional shape. Alternatively, the first through-holes 32 in the protector 13 may be changed to this cross-sectional shape.

[0087] <Effects> Next, the effects of this embodiment will be described.

[0088] In this embodiment, as shown in Figure 1, the acoustic device 10 comprises a diaphragm 27 that generates sound by vibrating, and at least one protective member 13, 14. The protective members 13, 14 are positioned on the front side of the diaphragm 27 to protect it.

[0089] Furthermore, in this embodiment, at least one protective member 13, 14 includes a special protective member 14. As shown in Figure 5, the special protective member 14 has a plurality of through holes 42 that penetrate in the front-rear direction of the device, and these plurality of through holes 42 include special holes 42. A special hole 42 is a hole in which a part of the edge is not visible when viewed from the centroid. For this reason, the balance of surface tension at the edge of the special hole 42 is easily disrupted, and a water film is less likely to form on the special hole 42. If a water film forms on the through hole 42, the sound pressure in the desired frequency band may decrease significantly, so this can be suppressed by having a plurality of through holes 42 that include special holes 42. As described above, according to this embodiment, acoustic performance can be improved.

[0090] Furthermore, in this embodiment, as shown in Figure 5, the special hole 42 has a radially elongated hole portion 43 extending along the radial direction and an outer circumferential elongated hole portion 44 extending along the circumferential direction. Therefore, the special hole 42 can be configured as a composite hole including a through hole (outer circumferential elongated hole portion 44) provided in the outer region.

[0091] Furthermore, in this embodiment, as shown in Figure 5, the special hole 42 has a first radially elongated hole portion 43 extending along the radial direction, a pair of second radially elongated hole portions 45 extending along the radial direction, an inner circumferentially elongated hole portion 46 provided in the central region and extending along the circumferential direction, and an outer circumferentially elongated hole portion 44 provided in the outer region and extending along the circumferential direction. The pair of second radially elongated hole portions 45 are located on both sides in the circumferential direction with respect to the first radially elongated hole portion 43. The inner circumferentially elongated hole portion 46 connects the first radially elongated hole portion 43 and the pair of second radially elongated hole portions 45. The first radially elongated hole portion 43 and the outer circumferentially elongated hole portion 44 are connected. Therefore, the shape of the special hole 42 can be made even more complex, and the formation of a water film on the special hole 42 can be further suppressed. In this embodiment, the special hole 42 has a pair of second radially elongated hole portions 45, but either one of the pair of second radially elongated hole portions 45 may be omitted.

[0092] Furthermore, in this embodiment, the multiple through holes 42 do not include any through holes other than the special holes 42, which have a shape in which a portion of the edge is not visible when viewed from the centroid. Therefore, the formation of a water film on the multiple through holes 42 can be suppressed. In other words, since all of the multiple through holes 42 are special holes 42 with a shape in which a portion of the edge is not visible when viewed from the centroid, the balance of surface tension is easily disrupted, and the formation of a water film can be suppressed.

[0093] Furthermore, in this embodiment, as shown in Figure 1, at least one protective member 13, 14 includes an additional protective member 13. As shown in Figure 3, the additional protective member 13 has a plurality of additional through holes 32 that penetrate in the front-rear direction of the device. The plurality of additional through holes 32 are provided in positions that do not overlap with the plurality of through holes when viewed from the front side. Therefore, it is possible to prevent foreign objects such as pebbles from entering by passing through both the through holes 42 and the additional through holes 32.

[0094] Furthermore, in this embodiment, as shown in Figure 3, the multiple additional through holes 32 include additional special holes 32 with a shape in which part of the edge is not visible when viewed from the centroid (see Figure 13). Therefore, the balance of surface tension at the edge of the additional special holes 32 is easily disrupted, and the formation of a water film on the additional special holes 32 can be suppressed.

[0095] Furthermore, in this embodiment, as shown in Figure 3, the additional special hole 32 has a radially elongated hole portion 33 extending along the radial direction and a circumferentially elongated hole portion 34 extending along the circumferential direction. The circumferentially elongated hole portion 34 is provided in the outer region. The radially elongated hole portion 33 is provided in a region that spans the central region and the outer region. Therefore, the additional special hole 32 can be configured as a composite hole including a through hole (circumferentially elongated hole portion 34) provided in the outer region.

[0096] Furthermore, in this embodiment, the multiple through holes 32 do not include any through holes other than the special holes 32, which have a shape in which a portion of the edge is not visible when viewed from the centroid. Therefore, the formation of a water film in the through holes 32 can be suppressed.

[0097] While preferred embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above.

[0098] In the above embodiment, the acoustic device body 11 includes diaphragm assemblies 27 and 28 in which a diaphragm 27 and an edge 28, which are formed separately from each other, are integrated; however, the disclosure is not limited thereto. The diaphragm 27 and the edge 28 may be formed as a single unit.

[0099] In the above embodiment, the diaphragm 27 has a shape that is convex toward the rear, but the diaphragm of this disclosure is not limited to this. The diaphragm may have a shape that is convex toward the front.

[0100] In the above embodiment, the angle of inclination of the rear surface of the protector 13 is different in the central region and the outer region, but the angle of inclination may be the same.

[0101] In the above embodiment, the outer circumferential elongated hole 44 is located radially outward from the circumferential elongated hole 34 of the protector 13, but it may also be located radially inward from the circumferential elongated hole 34.

[0102] In the above embodiment, the second radial elongated hole 45 is provided in the central region, but the disclosure is not limited thereto.

[0103] In the above embodiment, the inner circumferential elongated hole 46 connects the longitudinal intermediate portion of one of the pair of second radial elongated hole 45s to the longitudinal intermediate portion of the other second radial elongated hole 45, but the disclosure is not limited thereto. The position where the inner circumferential elongated hole 46 connects the pair of second radial elongated hole 45 may be at another position.

[0104] 10 Acoustic device 13 Protector (special protective member, additional protective member) 14 Front cover (special protective member, additional protective member) 27 Diaphragm 32 First through hole (special hole, additional special hole, through hole, additional through hole) 33 Radial elongated hole 34 Circumferential elongated hole 42 Second through hole (special hole, additional special hole, through hole, additional through hole) 43 First radial elongated hole (radial elongated hole) 44 Outer circumferential elongated hole (circumferential elongated hole) 45 Second radial elongated hole (radial elongated hole) 46 Inner circumferential elongated hole (circumferential elongated hole) 132 First through hole (special hole, additional special hole, through hole, additional through hole) 133 Radial elongated hole 134 Circumferential elongated hole 142 Second through hole (special hole, additional special hole, through hole, additional through hole) 143 First radial elongated hole (radial elongated hole) 144 Outer circumferential elongated hole (circumferential elongated hole) 145 Second radial elongated hole (radial elongated hole) 146 Inner circumferential elongated hole (circumferential elongated hole) 232 First through hole (special hole, additional special hole, through hole, additional through hole) 233 Radial elongated hole 234 Circumferential elongated hole 242 Second through hole (special hole, additional special hole, through hole, additional through hole) 243 First radial elongated hole portion (radial elongated hole portion) 244 Outer circumferential elongated hole portion (circumferential elongated hole portion) 245 Second radial elongated hole portion (radial elongated hole portion) 246 Inner circumferential elongated hole portion (circumferential elongated hole portion)

Claims

1. An acoustic device comprising: a diaphragm that generates sound by vibrating; and at least one protective member positioned on the front side of the diaphragm to protect the diaphragm, wherein the at least one protective member includes a special protective member, the special protective member has a plurality of through holes that penetrate in the front-to-back direction of the device, and the plurality of through holes include special holes in which a portion of the edge is not visible when viewed from the centroid.

2. The acoustic device according to claim 1, wherein the special hole comprises a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction.

3. The acoustic device according to claim 2, wherein the circumferential elongated hole is provided in the outer region, and the radial elongated hole is provided in a region spanning the central region and the outer region.

4. The acoustic device according to claim 2 or 3, wherein the circumferential elongated hole portion and the radial elongated hole portion form a portion that is T-shaped, Y-shaped, or arrow-shaped.

5. The acoustic device according to claim 2, wherein the radially elongated hole is provided in the central region or in a region spanning the central region and the outer region, and the circumferentially elongated hole is provided in the central region.

6. The acoustic device according to claim 2 or claim 5, wherein the circumferential elongated hole portion and the radial elongated hole portion form a portion with a cross-shaped hole.

7. The acoustic device according to claim 1, wherein the special hole comprises a first radially elongated hole portion extending along the radial direction, a pair of second radially elongated holes extending along the radial direction, and an inner circumferentially elongated hole portion provided in the central region and extending along the circumferential direction, wherein the pair of second radially elongated holes are located on both sides in the circumferential direction relative to the first radially elongated hole portion, and the inner circumferentially elongated hole portion connects the first radially elongated hole portion and the pair of second radially elongated holes.

8. The acoustic device according to claim 1, wherein the special hole comprises: a first radially elongated hole portion extending in the radial direction; a pair of second radially elongated holes extending in the radial direction; an inner circumferentially elongated hole portion provided in the central region and extending in the circumferential direction; and an outer circumferentially elongated hole portion provided in the outer region and extending in the circumferential direction, wherein the pair of second radially elongated holes are located on both sides in the circumferential direction with respect to the first radially elongated hole portion; the inner circumferentially elongated hole portion connects the first radially elongated hole portion and the pair of second radially elongated holes; and the first radially elongated hole portion and the outer circumferentially elongated hole portion are connected.

9. The acoustic device according to any one of claims 1 to 8, wherein a plurality of special holes are provided, and the plurality of special holes are arranged along the circumferential direction.

10. The acoustic device according to claim 1, wherein the plurality of through holes do not include through holes other than special holes in which a portion of the edge is not visible when viewed from the centroid.

11. The acoustic device according to any one of claims 1 to 10, wherein the at least one protective member includes an additional protective member, the additional protective member has a plurality of additional through holes penetrating in the front-rear direction of the device, and the plurality of additional through holes are provided in positions that do not overlap with the plurality of through holes when viewed from the front side.

12. The acoustic device according to any one of claims 1 to 10, wherein the at least one protective member includes an additional protective member, the additional protective member has a plurality of additional through holes penetrating in the front-rear direction of the device, and the plurality of additional through holes include additional special holes having a shape in which a portion of the edge is not visible when viewed from the centroid.

13. The acoustic device according to claim 12, wherein the additional special hole comprises a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction, the circumferentially elongated hole portion being provided in the outer region and the radially elongated hole portion being provided in a region spanning the central region and the outer region.

14. The acoustic device according to claim 1, wherein the special hole has a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction, the circumferentially elongated hole portion is provided in the outer region, and the radially elongated hole portion is provided in a region spanning the central region and the outer region, the at least one protective member includes an additional protective member, the additional protective member has a plurality of additional through holes penetrating in the front-rear direction of the device, the plurality of additional through holes include an additional special hole having a shape in which a part of the edge is not visible when viewed from the centroid position, the additional special hole has a radially elongated hole portion extending along the radial direction and a circumferentially elongated hole portion extending along the circumferential direction, the circumferentially elongated hole portion is provided in the outer region, and the radially elongated hole portion is provided in a region spanning the central region and the outer region.

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