Acoustic device

Abstract

To inhibit deformation of a diaphragm.SOLUTION: An acoustic device 10 includes: a diaphragm 28 which vibrates to generate sound; a frame 20 supporting the diaphragm 28; and a stopper part 20A which is provided between the diaphragm 28 and the frame 20 and inhibits deformation of the diaphragm 28 by the diaphragm 28 partially contacting therewith when the diaphragm 28 is pressed toward the frame 20 side. The diaphragm 28 and the stopper part 20A make a line contact when the diaphragm 28 is pressed toward the frame 20 side.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an audio device. [Background technology]

[0002] The following Patent Document 1 discloses an acoustic device that generates sound by vibrating a vibrating body having a diaphragm and an edge portion joined to the outer periphery of the diaphragm. In the acoustic device described in this document, the internal space of the main body case and the external space are partitioned via the vibrating body. In addition, a vibrating body regulating portion is provided at a position facing the edge portion of the vibrating body. When the air pressure in the internal space of the main body case suddenly drops, the vibrating body is sucked toward the inside of the main body case, and at this time, the edge portion of the vibrating body hits the vibrating body regulating portion. This prevents the edge portion from being deformed in an inverted manner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-034864 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the configuration of the acoustic device described in Patent Document 1 above is useful from the viewpoint of suppressing inversion of the edge portion when the air pressure in the internal space of the main body case suddenly drops, but there is room for improvement in terms of suppressing deformation of the diaphragm (diaphragm portion).

[0005] SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an acoustic device capable of suppressing deformation of a diaphragm. [Means for solving the problem]

[0006] The first aspect of the acoustic device comprises a diaphragm that generates sound by vibrating, a frame that supports the diaphragm, and a stopper portion provided between the diaphragm and the frame, with which a part of the diaphragm abuts when the diaphragm is pressed toward the frame, suppressing deformation of the diaphragm, and when the diaphragm is pressed toward the frame, the diaphragm and the stopper portion abut at a line.

[0007] In the acoustic device of the first aspect, sound is generated by the vibration of the diaphragm. The diaphragm is supported by a frame. In the acoustic device of the first aspect, when the diaphragm is pressed toward the frame, the diaphragm and the stopper portion come into contact with each other along a line. This makes it possible to prevent the diaphragm from being deformed when the diaphragm is pressed toward the frame.

[0008] The second aspect of the acoustic device is the acoustic device of the first aspect, in which the outer periphery of the diaphragm and the frame are connected via an edge member, a portion of which deforms as the diaphragm vibrates, and a joint is formed in which a portion of the edge member and the outer periphery of the diaphragm are joined in a superimposed state, and when the diaphragm is pressed towards the frame, the joint and the stopper portion abut against each other.

[0009] In the acoustic device of the second aspect, the outer periphery of the diaphragm and the frame are connected via an edge member, a portion of which deforms as the diaphragm vibrates. Here, a portion of the edge member and the outer periphery of the diaphragm are joined together in a superimposed state to form a joint. In the acoustic device of the second aspect, when the diaphragm is pressed toward the frame, the joint and the stopper portion come into contact with each other. This makes it possible to suppress deformation of the diaphragm when the diaphragm is pressed toward the frame.

[0010] The acoustic device of the third aspect is the acoustic device of the second aspect, wherein the thickness of the portion of the edge member that is joined to the outer periphery of the diaphragm is greater than the thickness of the portion of the edge member that deforms in response to vibration of the diaphragm.

[0011] In the acoustic device of the third aspect, the outer periphery of the diaphragm can be more effectively reinforced by the edge member than in a configuration in which the thickness of the portion of the edge member joined to the outer periphery of the diaphragm and the thickness of the portion of the edge member that deforms with the vibration of the diaphragm are set to the same dimension, i.e., the joint that abuts against the stopper portion can be more effectively reinforced.

[0012] An acoustic device of a fourth aspect is an acoustic device of any one of the first to third aspects, in which a voice coil is fixed to the inner periphery of the diaphragm and the voice coil and the frame are connected via a damper, and the frame is provided with a damper regulating portion that regulates displacement of the damper toward the frame, and the distance that the voice coil moves to a position where the damper abuts against the damper regulating portion is set to be greater than or equal to the distance that the voice coil moves to a position where the diaphragm abuts against the stopper portion.

[0013] In the acoustic device of the fourth aspect, the distance that the voice coil moves to the position where the damper abuts against the damper restricting portion is set to be equal to or greater than the distance that the voice coil moves to the position where the diaphragm abuts against the stopper portion, thereby making it possible to prevent the movement of the damper from being impeded by the stopper portion.

[0014] The fifth aspect of the acoustic device is the acoustic device of the fourth aspect, wherein a yoke is provided around the voice coil, and the distance that the voice coil moves to the position where the diaphragm abuts the stopper portion is set to be less than the distance that the voice coil moves to the position where the voice coil abuts the yoke.

[0015] In the acoustic device of the fifth aspect, the distance that the voice coil moves to the position where the diaphragm abuts on the stopper is set to be less than the distance that the voice coil moves to the position where the voice coil abuts on the yoke, thereby making it possible to prevent the voice coil from abutting on the yoke before the diaphragm abuts on the stopper.

[0016] An audio device according to a sixth aspect is the audio device according to any one of the first to fifth aspects, wherein the stopper portion is formed integrally with the frame.

[0017] In the audio device of the sixth aspect, an increase in the number of parts of the audio device can be suppressed, compared to a configuration in which the stopper portion is formed separately from the frame.

[0018] An acoustic device according to a seventh aspect is the acoustic device according to any one of the first to sixth aspects, wherein the surface of the stopper portion facing the diaphragm is curved.

[0019] In the acoustic device of the seventh aspect, the contact pressure between the stopper portion and the joint portion can be reduced, compared to a configuration in which the surface of the stopper portion facing the diaphragm is not curved.

[0020] An acoustic device of an eighth aspect is an acoustic device of any one of the first to seventh aspects, in which when the diaphragm is pressed towards the frame, the outer periphery of the diaphragm abuts against the stopper portion.

[0021] In the acoustic device of the eighth aspect, when the diaphragm is pressed toward the frame, the outer periphery of the diaphragm comes into contact with the stopper portion, which makes it possible to prevent the outer periphery of the diaphragm from deforming in an inverted manner relative to the inner periphery.

[0022] An acoustic device of a ninth aspect is an acoustic device of any one of the first to eighth aspects, in which a plurality of the stopper portions are arranged in a radial direction of the diaphragm, and when the diaphragm is pressed toward the frame, the diaphragm abuts against the plurality of the stopper portions.

[0023] In the acoustic device of the ninth aspect, the multiple stopper portions are arranged in a radial direction of the diaphragm, and when the diaphragm is pressed toward the frame, the diaphragm abuts against the multiple stopper portions. In this configuration, it is possible to suppress an increase in contact pressure between the diaphragm and the stopper portions compared to a configuration in which a single stopper portion is provided. Effect of the Invention

[0024] The acoustic device according to the present invention has the excellent effect of being able to suppress deformation of the diaphragm. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a cross-sectional perspective view of the audio device taken along the front-rear direction. [Diagram 2] 2 is a side cross-sectional view of the acoustic device taken along the front-rear direction. FIG. [Diagram 3] 2 is an enlarged cross-sectional side view of the acoustic device taken along the front-rear direction. FIG. [Figure 4] 5 is a cross-sectional view corresponding to FIG. 3 and showing another example of the edge member. FIG. [Diagram 5] 5 is a cross-sectional view corresponding to FIG. 3 and showing another example of the stopper portion. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] An acoustic device 10 according to an embodiment of the present invention will be described with reference to Figs. 1 to 3. The acoustic device 10 of this embodiment is mounted on a vehicle, for example, and can be used as an external sound system (ESS) such as a horn or an acoustic vehicle alerting system (AVAS). The front and rear sides of the acoustic device 10 are indicated by arrows FR and RR, respectively. In the following description, when the front and rear directions are simply indicated, they refer to the front and rear directions of the acoustic device 10, unless otherwise specified.

[0027] 1 and 2, an acoustic device 10 includes a main baffle 12 formed in a box shape, and a front cover 14 attached to the front of the main baffle 12. The acoustic device 10 also includes an acoustic device body 16 that is supported by the main baffle 12 while being disposed within the main baffle 12. In addition, in Figs. 1 and 2, hatching of cross sections has been omitted in consideration of ease of viewing the drawings.

[0028] The main baffle 12 is formed in a cylindrical shape with a bottom that is open on the front side. Specifically, the main baffle 12 has a rear wall portion 12A formed in a disk shape with the thickness direction being in the front-rear direction. The main baffle 12 also has a cylindrical portion 12B extending forward from the radially outer end of the rear wall portion 12A and formed in a cylindrical shape with the axial direction being in the front-rear direction.

[0029] The front cover 14 is formed in a cylindrical shape with a bottom that is open on the rear side. Specifically, the front cover 14 includes a front wall portion 14A that is disposed on the front side of a diaphragm 28 described later. The front cover 14 also includes a cylindrical portion 14B that extends from the outer circumferential end of the front wall portion 14A toward the rear side and is formed in a cylindrical shape with the front-rear direction as the axial direction. The rear end of the cylindrical portion 14B and the front end of the cylindrical portion 12B of the main baffle 12 are joined. As a result, a space in which the acoustic device main body 16 is disposed is formed between the main baffle 12 and the front cover 14. The joint between the rear end of the cylindrical portion 14B and the front end of the cylindrical portion 12B of the main baffle 12 is sealed with a sealant (for example, an adhesive). As a result, the watertightness of the joint between the rear end of the cylindrical portion 14B and the front end of the cylindrical portion 12B of the main baffle 12 is ensured.

[0030] The center of the front wall 14A is a convex portion 14C that protrudes toward the diaphragm 28, which will be described later. The rear surface of the convex portion 14C is disposed along the front surface of the diaphragm 28. A plurality of through holes 14D, each having a long hole shape, are formed in the front wall 14A at a location corresponding to the convex portion 14C. A plurality of drain holes 14E are formed around the convex portion 14C in the front wall 14A.

[0031] A second front cover 18 is attached from the front side to the center of the front wall 14A of the front cover 14. The second front cover 18 covers, from the front side, a portion of the front wall 14A that covers a diaphragm 28 and an edge member 30, which will be described later. In other words, the diaphragm 28 and the edge member 30, which will be described later, are protected from the front side by the front wall 14A of the front cover 14 and the second front cover 18. The second front cover 18 is also formed with a plurality of second through holes 18A and a plurality of second drainage holes 18B.

[0032] As shown in Figures 2 and 3, the acoustic device main body 16 includes a frame 20, a magnetic circuit section 22 supported by the frame 20, a voice coil 24 arranged within the frame 20, a damper 26 provided between the voice coil 24 and the frame 20, a diaphragm 28 fixed to the voice coil 24, and an edge member 30 connecting the diaphragm 28 to the frame 20.

[0033] The frame 20 is formed in a generally stepped cylindrical shape with a larger opening at the front side than at the rear side. The opening at the front side of the frame 20 is closed by a diaphragm 28 and an edge member 30, which will be described later.

[0034] The magnetic circuit section 22 applies a magnetic field to the voice coil 24 described later. The magnetic circuit section 22 includes a yoke 32 formed in a bottomed cylindrical shape, a disk-shaped magnet 34 fixed to the bottom surface of the yoke 32, and a disk-shaped top plate 36 laminated on the magnet. The yoke 32 and the top plate 36 are formed using a soft magnetic material. The yoke 32 opens toward the front side and is provided so as to close the opening on the rear side of the frame 20. A gap is formed between the magnet 34 and the top plate 36 and the yoke 32, and a part of the voice coil 24 described later is arranged in this gap.

[0035] The voice coil 24 includes a cylindrical bobbin 38 and a coil 40 formed along the bobbin 38. The diaphragm 28, which will be described later, is fixed to the front end of the bobbin 38. The coil 40 is formed by winding a linear conductor made of a conductive material along the bobbin 38. A pair of end portions of the conductor forming the coil 40 are respectively connected to a pair of terminals, not shown.

[0036] The damper 26 is formed in a disk shape with an opening formed in the radial center and in a wave shape that is repeatedly curved in the front-rear direction along the radial direction. The voice coil 24 is inserted into the opening formed in the center of the damper 26. The inner peripheral portion of the damper 26 is joined to the bobbin 38 of the voice coil 24, and the outer peripheral portion of the damper 26 is joined to the frame 20. Thus, the bobbin 38 and the frame 20 are connected via the damper 26.

[0037] The vibration plate 28 is formed in a circular shape when viewed from the front-rear direction, and is formed in a shape with a concave opening at the front side. The vibration plate 28 includes an outer peripheral portion 28A formed in a ring shape constituting the radial outer portion of the vibration plate 28, and an inner peripheral portion 28B constituting the radial center portion of the vibration plate 28 and formed integrally with the outer peripheral portion 28A. The outer peripheral portion 28A is formed in a funnel shape narrowing from the front side to the rear side. The inner peripheral portion 28B is formed in a shape that is convex toward the rear side and is recessed in a concave shape at the front side. Note that the arrow R indicates the radial outside of the vibration plate 28, and the arrow C indicates the circumferential direction of the vibration plate 28. The radial direction of the vibration plate 28 (the direction of the arrow R and the direction opposite to the arrow R) and the circumferential direction of the vibration plate 28 (the direction of the arrow C and the direction opposite to the arrow C) are perpendicular to the front-rear direction. Hereinafter, when the radially outer and inner directions are simply indicated, they refer to the radially outer and inner directions of the diaphragm 28, unless otherwise specified. Also, when the circumferential direction is simply indicated, they refer to the circumferential direction of the diaphragm 28, unless otherwise specified.

[0038] The edge member 30 is made of an elastic material such as rubber, and is formed in a ring shape when viewed from the front-rear direction. A radially outer end of the edge member 30 is joined to the front end of the frame 20. A radially inner end of the edge member 30 is joined to a radially outer end of the outer periphery 28A of the diaphragm 28 in a state where the radially outer end of the outer periphery 28A is overlapped with the radially outer end of the outer periphery 28A in the front-rear direction.

[0039] Next, the configuration of the main parts of this embodiment will be described.

[0040] 3, in the acoustic device body 16 of this embodiment, the radially inner end 30A of the edge member 30 and the radially outer end 28A1 of the outer periphery 28A of the diaphragm 28 are joined in a state of being overlapped with each other to form a joint 42. In the joint 42, the radially inner end 30A of the edge member 30 is disposed forward of the radially outer end 28A1 of the outer periphery 28A of the diaphragm 28. Here, in this embodiment, the thickness of the portion of the edge member 30 joined to the outer periphery 28A of the diaphragm 28 (the radially inner end 30A) is the same as the thickness of the portion 30B of the edge member 30 that deforms with the vibration of the diaphragm 28.

[0041] A stopper portion 20A protruding toward the front side is provided at the middle portion of the frame 20 in the radial direction. The stopper portion 20A is formed in a substantially cylindrical shape with the front-rear direction as the axial direction. A surface 20B (a surface at the front end side) at the tip end side in the protruding direction of the stopper portion 20A is gently curved so as to be convex toward the front side in a cross section cut along the radial direction. The surface 20B at the tip end side in the protruding direction of the stopper portion 20A faces a joint portion 42 between the edge member 30 and the outer peripheral portion 28A of the diaphragm 28 in the front-rear direction. The stopper portion 20A may be formed without interruption along the circumferential direction, or may be interrupted in a part of the circumferential direction. The stopper portion 20A may be formed so as to be scattered along the circumferential direction. As shown in FIG. 2, the stopper portion 20A of this embodiment has a plurality of openings 20C that penetrate the stopper portion 20A in the radial direction. Therefore, it is possible to arrange the wiring 44 connected to the voice coil 24 through the openings 20C. In FIG. 3, the opening 20C is omitted.

[0042] As shown in FIG. 3, a damper restricting portion 20D that is convex toward the front side is formed at the rear opening of the frame 20. The damper 26 comes into contact with the damper restricting portion 20D to restrict the displacement of the damper 26. Here, the state shown in FIG. 3 is a state in which no current is applied to the voice coil 24. The position of the voice coil 24 in this state is called the neutral position. In this embodiment, the distance by which the voice coil 24 moves to the position where the damper 26 comes into contact with the damper restricting portion 20D (the distance from the neutral position to the rear side) is set to be equal to or greater than the distance by which the voice coil 24 moves to the position where the joint portion 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 comes into contact with the stopper portion 20A (the distance from the neutral position to the rear side).

[0043] In addition, in this embodiment, the distance that the voice coil 24 moves to the position where the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 abuts the stopper portion 20A (movement distance from the neutral position toward the rear side) is set to a distance that is less than the distance that the voice coil 24 moves to the position where the voice coil 24 abuts the bottom 32A of the yoke 32 (movement distance from the neutral position toward the rear side).

[0044] (Actions and Effects of the Present Embodiment) Next, the operation and effects of this embodiment will be described.

[0045] 1 to 3, in the acoustic device 10 of this embodiment, electricity is passed through the coil 40 of the voice coil 24 via wiring paths (not shown) and external connectors (not shown), etc. As a result, as the voice coil 24 moves in the front-rear direction, the diaphragm 28 vibrates to generate sound.

[0046] Furthermore, in the acoustic device 10 of this embodiment, when the diaphragm 28 is pressed toward the frame 20 due to water entering from the front side of the acoustic device 10, the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 comes into line contact with the stopper portion 20A. This places the outer periphery 28A of the diaphragm 28 in a supported state by the stopper portion 20A, and it is possible to prevent the outer periphery 28A of the diaphragm 28 from deforming in an inverted manner relative to the inner periphery 28B.

[0047] Furthermore, in the acoustic device 10 of this embodiment, the distance by which the voice coil 24 moves to the position where the damper 26 abuts against the damper restricting portion 20D (the distance from the neutral position to the rear) is set to be equal to or greater than the distance by which the voice coil 24 moves to the position where the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 abuts against the stopper portion 20A (the distance from the neutral position to the rear). This makes it possible to prevent the movement (displacement) of the damper 26 from being hindered by the stopper portion 20A.

[0048] Furthermore, in the acoustic device 10 of this embodiment, the distance over which the voice coil 24 moves to a position where the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 abuts against the stopper portion 20A (the distance moved rearward from the neutral position) is set to a distance less than the distance over which the voice coil 24 moves to a position where the voice coil 24 abuts against the bottom 32A of the yoke 32 (the distance moved rearward from the neutral position). This makes it possible to prevent the voice coil 24 from abutting against the bottom 32A of the yoke 32 before the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 abuts against the stopper portion 20A.

[0049] Furthermore, in the acoustic device 10 of this embodiment, the stopper portion 20A is formed integrally with the frame 20. This makes it possible to prevent an increase in the number of parts of the acoustic device 10, compared to a configuration in which the stopper portion 20A is formed separately from the frame 20.

[0050] Furthermore, in the acoustic device 10 of this embodiment, the surface 20B on the tip side in the protruding direction of the stopper portion 20A is gently curved. In this configuration, the contact pressure between the stopper portion 20A and the joint portion 42 between the edge member 30 and the outer circumferential portion 28A of the diaphragm 28 can be reduced compared to a configuration in which the surface 20B on the tip side in the protruding direction of the stopper portion 20A is not curved.

[0051] In the above-described example, the surface 20B on the tip side of the protruding direction of the stopper portion 20A is curved, but the present invention is not limited to this. Whether or not the surface 20B on the tip side of the protruding direction of the stopper portion 20A is curved may be appropriately determined in consideration of the expected contact pressure between the stopper portion 20A and the joint portion 42.

[0052] In the above-described example, the stopper portion 20A is integrally formed with the frame 20, but the present invention is not limited to this. Whether or not the stopper portion 20A is integrally formed with the frame 20 can be appropriately determined in consideration of the configuration of the frame 20, the manufacturing method, etc.

[0053] In the above example, the distance (movement distance from the neutral position toward the rear side) that the voice coil 24 moves to the position where the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 abuts against the stopper portion 20A is set to a distance less than the distance (movement distance from the neutral position toward the rear side) that the voice coil 24 moves to the position where the voice coil 24 abuts against the bottom 32A of the yoke 32, but the present invention is not limited to this. For example, in the case where there is no problem even if the voice coil 24 abuts against the bottom 32A of the yoke 32 before the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 abuts against the stopper portion 20A, each distance may be set outside the above range.

[0054] In the above example, the distance (movement distance from the neutral position to the rear side) over which the voice coil 24 moves to the position where the damper 26 abuts against the damper restricting portion 20D is set to be equal to or greater than the distance (movement distance from the neutral position to the rear side) over which the voice coil 24 moves to the position where the joint 42 between the edge member 30 and the outer periphery 28A of the diaphragm 28 abuts against the stopper portion 20A, but the present invention is not limited to this. For example, when it is not expected that the movement (displacement) of the damper 26 will be hindered by the stopper portion 20A, each distance may be set outside the above range.

[0055] In the above-described example, the thickness of the portion (radially inner end 30A) of the edge member 30 joined to the outer periphery 28A of the diaphragm 28 is the same as the thickness of the portion 30B of the edge member 30 that deforms with the vibration of the diaphragm 28, but the present invention is not limited to this. For example, as shown in FIG. 4, the thickness of the portion (radially inner end 30A) of the edge member 30 joined to the outer periphery 28A of the diaphragm 28 may be thicker than the thickness of the portion 30B of the edge member 30 that deforms with the vibration of the diaphragm 28. In this configuration, the radially outer end 28A1 of the outer periphery 28A of the diaphragm 28 can be effectively reinforced by the edge member 30 compared to the configuration shown in FIG. 3. That is, the joint 42 that abuts against the stopper portion 20A can be effectively reinforced.

[0056] In the above-described example, the stopper portion 20A is provided at one location in the radial direction, but the present invention is not limited to this. For example, as shown in FIG. 5, a configuration in which a plurality of stopper portions 20A are provided at multiple locations in the radial direction may be used. In the example shown in FIG. 5, a plurality of stopper portions 20A are provided in a state of being lined up in the radial direction at a position facing the outer periphery of the vibration plate 28. In this configuration, compared to a configuration in which a single stopper portion 20A is provided (a configuration in which the stopper portion 20A is provided at one location in the radial direction), it is possible to suppress an increase in the contact pressure between the vibration plate 28 and the stopper portion 20A. In the example shown in FIG. 5, the stopper portion forming member 46 is joined to the frame 20, and some of the stopper portions 20A among the plurality of stopper portions 20A are formed on the stopper portion forming member 46.

[0057] In addition, in the present embodiment, the configuration in which the diaphragm 28 and the edge member 30 are separate members has been described, but the present invention is not limited to this. For example, the diaphragm 28 and the edge member 30 may be integrally formed (a configuration in which the joint 42 is not formed).

[0058] Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it is of course possible to implement the present invention in various other modified forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0059] 10 Sound equipment 20 Frames 20A stopper part 20B Surface of the tip of the stopper in the protruding direction (surface of the stopper on the diaphragm side) 20D Damper Regulating Part 24 Voice coil 26 Damper 28 Diaphragm 28A Outer periphery of diaphragm 30 Edge material 32 York 42 Joint

Claims

1. A diaphragm that generates sound by vibrating; A frame supporting the diaphragm; a stopper portion provided between the diaphragm and the frame, the stopper portion being brought into contact with a part of the diaphragm when the diaphragm is pressed toward the frame to suppress deformation of the diaphragm; Equipped with When the diaphragm is pressed towards the frame, the diaphragm and the stopper portion come into line contact with each other.

2. an outer periphery of the diaphragm and the frame are connected via an edge member, a part of which is deformed in response to vibration of the diaphragm; A part of the edge member and an outer periphery of the diaphragm are joined together in a superposed state to form a joint, The acoustic device according to claim 1 , wherein the joint portion and the stopper portion come into contact with each other when the diaphragm is pressed toward the frame.

3. 3. The acoustic device according to claim 2, wherein a thickness of the edge member at a portion joined to an outer periphery of the diaphragm is greater than a thickness of a portion of the edge member that deforms in response to vibration of the diaphragm.

4. A voice coil is fixed to the inner periphery of the diaphragm, and the voice coil and the frame are connected via a damper. The frame is provided with a damper restricting portion that restricts displacement of the damper toward the frame, An acoustic device as described in any one of claims 1 to 3, wherein the distance that the voice coil moves to the position where the damper abuts the damper regulating portion is set to a distance greater than or equal to the distance that the voice coil moves to the position where the diaphragm abuts the stopper portion.

5. A yoke is provided around the voice coil, 5. The acoustic device according to claim 4, wherein the distance over which the voice coil moves until the diaphragm abuts against the stopper portion is set to a distance less than the distance over which the voice coil moves until the voice coil abuts against the yoke.

6. The acoustic device according to claim 1 , wherein the stopper portion is formed integrally with the frame.

7. The acoustic device according to claim 1 , wherein the surface of the stopper portion facing the diaphragm is curved.

8. The acoustic device according to claim 1 , wherein an outer periphery of the diaphragm comes into contact with the stopper portion when the diaphragm is pressed toward the frame.

9. A plurality of the stopper portions are arranged in a radial direction of the vibration plate, The acoustic device according to claim 1 , wherein the diaphragm comes into contact with the plurality of stopper portions when the diaphragm is pressed toward the frame.

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