Sound generator and method of manufacturing the same

Abstract

Disclosed is a sound generator including a sound-generating body (7), a base (2), a protective wall (22) and a vertical wall (23). The sound-generating body has a diaphragm (72) and a driving part (73) that generates sound by vibrating the diaphragm when electricity is supplied. The base includes a base cylinder (21) that accommodates the sound-generating body and a partition wall (24) that is formed with a sound-releasing hole (25) that guides the sound to a sound-releasing area. The base cylinder is divided into a first space (4) and a second space (5) by the diaphragm and the partition wall. The protective wall is configured to cover the sound-releasing area with a gap between the partition wall and the vertical wall in the vibration direction of the diaphragm, and the vertical wall connects the protective wall and the base cylinder. A sound-releasing space (6) that is connected to the first space through the sound-releasing hole is formed between the protective wall, the vertical wall and the partition wall. By opening the protective wall and the vertical wall in at least one direction, an outlet hole (61) is formed that outputs the sound guided from the first space to the sound-releasing space through the sound-releasing hole.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on Japanese Patent Application No. 2019-045656 filed on March 13, 2019, and Japanese Patent Application No. 2020-003162 filed on January 10, 2020, and the disclosed contents of the basic applications are incorporated into this application by reference. Technical Field

[0003] The present disclosure relates to a sound generator and a method for manufacturing the same. Background Art

[0004] At present, in Patent Document 1, a sounder for a vehicle approach notification device is proposed. In this sounder, a box body is formed by covering both ends of a base body having a cylindrical base body tube portion with a cover body and a shell, a sounding body is arranged in the box body, and a sound emitting hole is provided in the center of the cover body, and the sound emitted from the sounding body is emitted from the sound emitting hole. In addition, in this sounder, a plurality of sound emitting holes are arranged in a circular shape at the front and side positions of the sounder, specifically at the central position of the cover body and the side position of the base body opposite to the sounding body, so that a structure is formed that can emit sound to the front and the entire periphery of the sounder, so that it can emit sound when installed in any position of the vehicle.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-121249 Summary of the invention

[0008] However, in the sound-emitting body shown in Patent Document 1, since a plurality of sound-emitting holes are arranged in a circular shape on the side of the base body and in the center of the cover body so as to be installed at any position in the vehicle, sound will inevitably be emitted from the sound-emitting holes in the direction in which sound is not required to be emitted. Therefore, there is a problem that the sound penetrates or propagates into the vehicle cabin, and noise in the vehicle cabin may be generated.

[0009] Furthermore, when the sound generator disclosed in Patent Document 1 is mounted on a vehicle, since the sound is emitted from the front of the sound generator, it is necessary to ensure a space for the sound passage on the cover side, so that the vehicle parts cannot be mounted close to the front of the sound generator. Therefore, there is a problem that the sound generator cannot be arranged in a narrow space of the vehicle.

[0010] The present disclosure has been made in view of the above-mentioned problems, and an object thereof is to provide a sounder and a method for manufacturing the sounder that can further reduce the noise in the vehicle cabin and can arrange vehicle components close to the front position.

[0011] In order to achieve the above-mentioned purpose, one aspect disclosed is a sound generator that generates sound by vibrating a diaphragm, the sound generator comprising: a sound-generating body having a diaphragm and a driving part that generates sound by vibrating the diaphragm through electricity; and a base body, which includes a base body cylinder portion that accommodates the sound-generating body, and a partition wall, the partition wall being arranged on one end side of the axial direction of the base body cylinder portion, and having a sound-generating hole formed in the sound-generating area in a region where the sound-generating body is arranged as a sound-generating area for guiding the sound generated by the sound-generating body, the interior of the base body cylinder portion being divided into a first space and a second space by the diaphragm and the partition wall; wherein, in the vibration direction of the diaphragm, there is a protective wall that is arranged to cover the sound-generating area with a gap from the partition wall, and a vertical wall that connects the protective wall and the base body cylinder portion, a sound-generating space that is connected to the first space through the sound-generating hole is formed between the protective wall, the vertical wall and the partition wall, and a sound-generating space that is connected to the first space through the sound-generating hole is formed, and by opening the protective wall and the vertical wall in at least one direction, a sound-generating hole is formed to output the sound guided from the first space through the sound-generating hole to the sound-generating space.

[0012] Thus, the sound emitted by the sound-emitting body is output from the emission hole through the sound emission space and is output in one direction. Therefore, it is possible to suppress the emission of sound in an unnecessary direction and to suppress the penetration or propagation of unnecessary sound into the vehicle cabin. Furthermore, if a protective wall is provided in front of the sound emitter, that is, in the vibration direction of the diaphragm, so as to cover the sound emission hole, it is possible to install a vehicle component at a position adjacent to the protective wall in the installation space of the sound emitter on the vehicle.

[0013] According to one aspect disclosed, a method for manufacturing a sound generator that generates sound by vibrating a diaphragm includes a design process and an airtightness detection process. In the design process, the design is as follows: the dimension between the side of the partition wall opposite to the protective wall and the protective wall is set to Ya, and the distance from the side of the partition wall to the boundary between the inner periphery and the outer periphery of the diaphragm is set to Yb, satisfying Ya>Yb. In the airtightness detection process, the pressure of the second space is made higher than the pressure of the first space by inserting a clamp from the sound release hole and arranging the clamp in the sound release hole, thereby causing the diaphragm to expand toward the first space.

[0014] By setting at least Ya>Yb in this way, the use of a jig can contribute to stabilization of airtightness inspection and shortening of inspection time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view of the sound generator according to the first embodiment.

[0016] Figure 2 yes Figure 1 A bottom view of the sounder is shown.

[0017] Figure 3 yes Figure 1A top view of the sound generator is shown.

[0018] Figure 4 yes Figure 1 Right side view of the sounder shown.

[0019] Figure 5 yes Figure 1 Rear view of the sounder shown.

[0020] Figure 6 yes Figure 1 VI-VI section view in.

[0021] Figure 7 yes Figure 1 Section view VII-VII in the figure.

[0022] Figure 8 yes Figure 2 Section view VIII-VIII in FIG.

[0023] Fig. 9 This is a rear view of the sound generator with the housing removed.

[0024] Fig.10 It is a cross-sectional view of the sounder showing the state during the airtightness test.

[0025] Fig.11 This is an enlarged view showing the state where the stopper contacts the diaphragm during the airtightness test.

[0026] Fig.12 This is a cross-sectional view of the sound generator according to the second embodiment cut at the position of the standing wall and viewed from the front direction.

[0027] Fig.13 yes Fig.12 Section view XIII-XIII in FIG.

[0028] Fig.14 This is a cross-sectional view of the sound generator according to the third embodiment cut at the position of the standing wall and viewed from the front.

[0029] Fig.15 yes Fig.14 XV-XV section view in.

[0030] Fig.16 is a diagram showing the use of a fixture for Fig.14 The cross-sectional view of the sounder shown is when undergoing airtightness testing.

[0031] Fig.17 It is a front view of the sound generator according to the fourth embodiment.

[0032] Fig.18 yes Fig.17A bottom view of the sounder is shown.

[0033] Fig.19 yes Fig.17 Section view XIX-XIX in the figure.

[0034] Fig. 20 yes Fig.17 XX-XX section view in.

[0035] Fig.21 yes Fig.18 Section view XXI-XXI in FIG.

[0036] Fig. 22 This is an enlarged view showing the state where the stopper contacts the diaphragm during the airtightness test. DETAILED DESCRIPTION

[0037] The following will describe the embodiments of the present disclosure based on the drawings. In addition, in each of the following embodiments, the same or equivalent parts are described with the same reference numerals.

[0038] (First Embodiment)

[0039] The first embodiment will be described. The sounder of this embodiment is installed outside a vehicle compartment, for example, to generate an alarm sound. The sounder includes a box having two spaces formed therein, and generates sound through a sounding body disposed in the box.

[0040] Specifically, Figure 1 to Figure 6 As shown, the box 1 of the sound generator is composed of two parts, namely, a base 2 and a cover 3, each of which is made of resin.

[0041] The base body 2 includes a base body cylinder 21 having a substantially elliptical cylindrical shape, a protective wall 22 is formed so as to cover an opening on one end side of the axial direction of the base body cylinder 21, and an elliptical plate-shaped housing 3 is fitted so as to cover an opening on the other end side and is joined airtightly by bonding. The sounding body 7 described later is assembled in the opening on the other end side of the base body cylinder 21, but by bonding the elliptical housing 3 airtightly to the opening, waterproofness and airtightness of the side where the sounding body 7 is assembled are ensured.

[0042] like Figure 6 As shown, the protective wall 22 is connected to the base tube 21 through a vertical wall 23 erected along the outer edge of the base tube 21 except in one direction, and is configured to provide a gap of a predetermined size Ya between a surface 24a of a partition wall 24 constituting an end surface of one end side of the base tube 21. By covering the opening of one end side of the base tube 21 with the protective wall 22, more specifically, covering the sounding body 7 located inside the opening of one end side, the sounding body 7 cannot be detected from the front direction ( Figure 1The sound emitting body 7 can be directly seen by the sound source (in the normal direction), thereby suppressing the invasion of foreign objects such as water, snow and flying stones into the sound emitting body 7.

[0043] Then, if Figure 6 , Figure 7 As shown, the space inside the base cylinder 21 is divided into two parts by a partition wall 24 provided inside the base cylinder 21. Specifically, the partition wall 24 is provided with a sound emitting hole 25 for guiding the sound generated by the sound-emitting body 7 and a beam portion 26 around it, and the sound-emitting body 7 is arranged in a manner covering the sound emitting hole 25 and the beam portion 26, so that the space inside the base cylinder 21 is divided into two parts. In addition, the first space 4 is formed by the base cylinder 21, the partition wall 24, and the diaphragm 72 provided in the sound-emitting body 7, and the second space 5 is formed by the base cylinder 21, the partition wall 24, the housing 3, and the diaphragm 72.

[0044] In addition, the first space 4 is also connected to the sound-releasing space 6 described later, which is composed of the protection wall 22 and the vertical wall 23. The sound emitted to the first space 4 is transmitted through the sound-releasing space 6 from the sound source disposed in the sound source 23. Figure 1 The sound is output from the lower release hole 61. Hereinafter, the output direction of the sound from the release hole 61 is referred to as the sound emission direction.

[0045] like Figure 1 and Figure 8 As shown, the partition wall 24 is formed in a substantially elliptical shape, and a base tube portion 21 is provided at its outer edge in a manner protruding toward the side opposite to the protective wall 22. In addition, a vertical wall 23 is formed on the outer periphery of the base tube portion 21 and the partition wall 24 in a manner that divides the elliptical shape in half along the long diameter, and a vertical wall 23 is also extended from both ends of the long side direction of the elliptical shape toward the tangent direction, in other words, toward the release direction.

[0046] In the case of this embodiment, the protective wall 22 and the upright wall 23 are extended to protrude toward the discharge direction side compared to the base tube 21. Figure 2 , Figure 7 As shown in FIG. 1 , an opposing wall 27 is formed on the side opposite to the protective wall 22 across the base tube 21 in a manner opposite to the portion of the protective wall 22 that protrudes from the base tube 21. Furthermore, the protective wall 22, the vertical wall 23, and the opposing wall 27 are open in a direction intersecting the vibration direction. Figure 2 As shown, a sound release hole 61 is formed by the protective wall 22, the vertical wall 23 and the opposite wall 27, and a sound release space 6 is formed on the inner side of the box body 1 closer to the sound release hole 61 and surrounded by the protective wall 22, the vertical wall 23 and the partition wall 24. Figure 2As shown, the discharge hole 61 has a predetermined width W1 and is formed in a flat shape with the direction perpendicular to the short side direction as the long side direction, so that it is easy to apply to the vehicle. That is, the discharge hole 61 is formed in a rectangular shape with the side formed by the standing wall 23 as the short side direction and the side formed by the protective wall 22 as the long side direction by setting the standing wall 23 shorter than the protective wall 22. Therefore, by setting the vibration direction of the diaphragm 72 to the short side direction, the thickness of the product can be reduced, and even if it is a rectangular shape, the opening area required for generating sound pressure can be ensured.

[0047] In addition, if Figure 5 As shown, the protective wall 22, the vertical wall 23 and the relative wall 27 are set to a structure that only protrudes by a predetermined length P1 compared to the base tube 21, but they may not protrude. However, if they are set to a protruding structure, by adjusting their lengths, it is possible to obtain a resonance effect of the sound, or to obtain an effect of making the sound quality and sound pressure variable by adjusting the resonance frequency. In addition, since the protective wall 22, the vertical wall 23 and the relative wall 27 are set to a structure that protrudes compared to the base tube 21, the relative wall 27 is provided, but if they are not set to a protruding structure, the relative wall 27 may not be provided.

[0048] like Figure 1 , Figure 7 and Figure 8 As shown in FIG. 1 , the front ends of the protective wall 22, the vertical wall 23 and the opposite wall 27 terminate on the same plane. Hereinafter, the surface formed by the front ends of the protective wall 22, the vertical wall 23 and the opposite wall 27 is referred to as the discharge surface 62. In the case of the present embodiment, the discharge surface 62 is Figure 7 As shown, it is formed as a plane parallel to the vibration direction of the diaphragm 72, and as shown Figure 8 The plane shown is also parallel to the long side direction of the base tube 21. The sound output from the discharge hole 61 is discharged and transmitted to the outside with the normal direction of the discharge surface 62 as the center. Therefore, the sound discharge direction is determined based on the position of the discharge hole 61 or the normal direction of the discharge surface 62.

[0049] In addition, the area near the center of the partition wall 24 is used as a sound emitting area where a sound emitting body 7 that generates sound based on an electrical signal is arranged. Figure 1 , Figure 8 As shown in FIG. 1 , a plurality of sound-releasing holes 25 are formed by forming through holes in the partition wall 24. Figure 6 , Figure 7 As shown, the sound-emitting body 7 is arranged in the second space 5 in a manner of blocking the sound-emitting hole 25. More specifically, the sound-emitting hole 25 is blocked by the diaphragm 72 provided in the sound-emitting body 7. Therefore, the second space 5 is separated from the first space 4 by the diaphragm 72.

[0050] In addition, the airtightness between the first space 4 and the second space 5 is ensured by the diaphragm 72 and the like. Therefore, in order to suppress the change of the pressure applied to the diaphragm 72 due to the temperature change, the diaphragm 72 is provided. Figure 1 , Figure 8 As shown, a vent hole 241 for connecting the two spaces is formed at a position different from the sound emitting area on the partition wall 24. A vent film 242 is attached to the vent hole 241. The vent film 242 is made of a material that allows air to pass through and blocks water. The pressure change applied to the diaphragm 72 is adjusted by the vent film 242.

[0051] like Figure 1 , Figure 6 to Figure 8 As shown, the portion other than the sound emitting hole 25 in the sound emitting area is the beam portion 26. On one surface of the beam portion 26 on the diaphragm 72 side, a stopper 261 is formed. The stopper 261 is formed by partially protruding the beam portion 26. Figure 1 and Figure 8 As shown, in the case of this embodiment, the beam portion 26 is configured to include radial beams 262 extending radially from the center of the sound radiating area and circular beams 263 arranged concentrically. In the case of this embodiment, three circular beams 263 are provided.

[0052] In this embodiment, six radial beams 262 are provided at equal intervals. Three of them are formed at equal intervals of 120 degrees from the innermost circular beam among the circular beams 263 to the outer periphery of the sound emitting area, and the remaining three are formed from the second circular beam among the circular beams 263 to the outer periphery of the sound emitting area.

[0053] Since the beam 26 covers the area other than the sound emitting hole 25 in the sound emitting area, it is possible to prevent water spillage and flying stones from reaching the sound emitting body 7 during driving, and to prevent the sound emitting body 7 from being damaged by contact with water or stones. In the present embodiment, the one side 24a of the partition wall 24 including the beam 26, which faces the protective wall 22, is a flat surface, but may have projections and depressions. However, in the case of manufacturing the entire base 2 at one time by resin molding, since a sliding mold is arranged between the one side 24a and the protective wall 22, it is set to a shape that allows demolding of the sliding mold.

[0054] In addition, during the airtightness test, when the diaphragm 72 is displaced, the stopper 261 contacts the diaphragm 72 to limit the displacement of the diaphragm 72 in the vibration direction. Thus, damage caused by excessive deformation of the diaphragm 72 is suppressed. Figure 6 , Figure 7 As shown, the stopper 261 is configured to be opposite to the diaphragm 72 and is set to a shape corresponding to the diaphragm 72.

[0055] Specifically, the stopper 261 is formed by making the radial beam 262 and the second circular beam from the center of the three circular beams 263 protrude toward the diaphragm 72 side. The portion of the stopper 261 protruding from the circular beam 263 constitutes a cylindrical portion 261a protruding in a circular shape along the circular beam 263. In addition, the portion of the stopper 261 protruding from the radial beam 262 constitutes an inclined portion 261b inclined toward the radial outside with the cylindrical portion 261a as the center. If the distance from one surface 24a in the stopper 261 is set as the height, the cylindrical portion 261a is formed to have the same height throughout the entire circumference and is the highest. In addition, the inclined portion 261b is the same height as the cylindrical portion 261a in the portion connected to the cylindrical portion 261a, and the height gradually decreases as it moves away from the cylindrical portion 261a.

[0056] In addition, the inclined portion 261b is formed on all radial beams 262, but can also be formed only on a portion, for example, only on the portion from the second circular beam 263 to the outer periphery of the sound projection area. Conversely, it can also be formed only on the portion from the innermost circular beam 263 to the outer periphery of the sound projection area.

[0057] like Figure 1 to Figure 4 , Figure 6 to Figure 9 As shown, a substantially square cylindrical connector 29 for electrically connecting the sounding body 7 to an external wiring harness (not shown) is formed on the outside of the base cylinder 21. The connector 29 intersects with the vibration direction of the diaphragm 72 and is arranged on the outside of the vertical wall 23 in a direction parallel to the partition wall 24, so as to reduce the thickness of the product. Figure 6 As shown, in the portion of the base cylinder 21 where the connector 29 is formed, a through hole 291 is formed that penetrates the base cylinder 21 to connect the inside of the connector 29 to the second space 5 , and the terminal 9 is press-fitted through the through hole 291 .

[0058] The terminal 9 is fixed to the base tube 21 by an adhesive inside the base tube 21, and the through hole 291 formed for arranging the terminal 9 is blocked by the adhesive and the terminal 9. The terminal 9 is connected to the pin 78 described later in the second space 5.

[0059] like Figure 6 As shown, the terminal 9 has a flat rod-shaped terminal portion 91 with one direction as the long side direction, and a connecting portion 92 connected to the pin 78. The terminal portion 91 is a portion inserted into the through hole 291, and is configured so that one end is located on the second space 5 side and the other end is located inside the connector 29. The connecting portion 92 is connected to one end of the terminal portion 91 located on the second space 5 side, and is formed in a shape that is bent in a direction intersecting with the long side direction of the terminal portion 91, or in this embodiment, in a direction orthogonal to the long side direction.

[0060] like Figure 6 , Figure 7 , Fig. 9 As shown, the sound-emitting body 7 includes a frame 71 , a diaphragm 72 , and a driving unit 73 that causes the diaphragm 72 to vibrate.

[0061] The frame 71 is roughly stepped cylindrical and made of resin. The frame 71 is open at both ends in the axial direction, and has a cylindrical portion 711 with a wider opening width constituting one opening, a cylindrical portion 712 with a narrower opening width constituting the other opening, and a disc-shaped stepped portion 713 connecting the cylindrical portions 711 and 712. The opening portion formed by the cylindrical portion 711 is blocked by the diaphragm 72. In addition, the frame 71 is fixed to the base 2 by being airtightly bonded to the partition wall 24 at the end on the side where the opening is blocked by the diaphragm 72.

[0062] In addition, if Figure 6 , Fig. 9 As shown, a through hole 714 is formed on the step portion 713 to connect the inside and outside of the frame 71, and a second space 5 is formed that communicates between the inside and outside of the frame 71 through the through hole 714. In addition, the second space 5 is separated from the first space 4 by the partition wall 24 and the diaphragm 72.

[0063] The diaphragm 72 constitutes a vibration plate, and generates sound by vibrating. Figure 6 As shown, the inner peripheral portion 721 of the diaphragm 72 is formed into a convex surface convex toward the first space 4. Moreover, the outer peripheral portion 722 of the diaphragm 72 is inclined toward the first space 4. Specifically, the outer peripheral portion 722 is formed into a hollow truncated cone shape extending from the outer edge of the inner peripheral portion 721 toward the first space 4.

[0064] The circular boundary between the inner circumference 721 and the outer circumference 722 has the same diameter as the cylindrical portion 261a of the stopper 261 and is disposed opposite to each other. In addition, the inclination of the outer circumference 722 is formed into the same shape as the inclined portion 261b and is disposed opposite to each other. Figure 6 As shown, at the circular boundary between the inner circumference 721 and the outer circumference 722, a circular end 723 is formed on the diaphragm 72. The circular end 723 is opposite to the cylindrical portion 261a and is displaced the most in the vibration direction of the diaphragm 72 when the diaphragm 72 is displaced. Fig.10 , Fig.11 As shown, the cylindrical portion 261a abuts against the circular end portion 723, and the inclined portion 261b abuts against the outer peripheral portion 722. The circular end portion 723 is fixed to one end of the bobbin 74 provided in the sounding body 7 by an adhesive on the driving portion 73 side, and the bobbin 74 is integrated with the diaphragm 72. Therefore, the cylindrical portion 261a can abut against the hard and strong portion of the diaphragm 72, which is also a portion with high strength.

[0065] As described later, in the sound-generating body 7, sound is generated by the vibration of the diaphragm 72. In order to generate sound with a sufficiently large sound pressure, it is necessary to increase the distance between the diaphragm 72 and the stopper 261 to a certain extent. Therefore, the distance between the surface of the diaphragm 72 in contact with the stopper 261 and the surface of the stopper 261 in contact with the diaphragm 72 is greater than the displacement of the diaphragm 72 caused by the sound-generating operation, so as to prevent the diaphragm 72 from contacting the stopper 261 due to the sound-generating action. In addition, when performing the airtightness test, the diaphragm 72 is displaced more than during the sound-generating action and abuts against the stopper 261.

[0066] For example, the distance between the surface of the diaphragm 72 that contacts the stopper 261 and the surface of the stopper 261 that contacts the diaphragm 72 is about 1 mm to 3 mm.

[0067] Furthermore, a spring portion 724 having a ring shape when viewed from the axial direction of the outer peripheral portion 722 and an S-shaped cross section along the radial direction is connected to the end portion of the outer peripheral portion 722 on the opposite side to the inner peripheral portion 721. The diaphragm 72 is bonded to the frame 71 at the end of the spring portion 724. In the present embodiment, the inner peripheral portion 721, the outer peripheral portion 722, the circular end portion 723, and the spring portion 724 are formed by a single film.

[0068] The driving part 73 is configured to close the cylindrical part 712 having the narrower opening width among the two openings of the frame 71. Figure 6 As shown, the driving portion 73 includes a bobbin 74 , a voice coil 75 , and a magnetic circuit portion 76 .

[0069] The bobbin 74 is formed in a cylindrical shape, connected to the inner side of the circular end 723 at the outer edge of the inner circumference 721 of the diaphragm 72, and is erected from the diaphragm 72 toward the inside of the second space 5. The voice coil 75 is wound around the outer side of the bobbin 75. The bobbin 74 corresponds to the core.

[0070] The magnetic circuit portion 76 is used to apply a magnetic field to the voice coil 75, and includes a disk-shaped magnet 761 having one side and the other side, a top plate 762 connected to one side of the magnet 761, and a yoke 763 connected to the other side of the magnet 761. The magnetic circuit portion 76 is formed by arranging the magnet 761 and the top plate 762 at the bottom of the yoke 763, and a gap is provided between the cylindrical portion of the yoke 763 and the magnet 761 and the top plate 762, so that the bobbin 74 and the voice coil 75 are arranged in the gap. The yoke 763 is embedded in the inner side of the cylindrical portion 712 and bonded to the entire area from the opening entrance side of the cylindrical portion to the outer circumference, so that the magnetic circuit portion 76 and the frame 71 are integrated.

[0071] With this structure, a magnetic field generated between the side surface of the top plate 762 and the side surface of the cylindrical portion of the yoke 763 is applied to the voice coil 75 wound on the bobbin 74. Therefore, when a current is passed through the voice coil 75 in a state where a magnetic field is applied, the bobbin 74 is displaced in the axial direction while being embedded in the cylindrical portion of the yoke 763. As a result, the diaphragm 72 vibrates and generates sound.

[0072] In addition, the sounding body 7 has a pin 78 electrically connected to the voice coil 75. Although not shown in the figure, the pin 78 is electrically connected to the voice coil 75 by welding or the like, and is led out radially outward from the voice coil 75. In this embodiment, the pin 78 is integrated with the frame 71 by integral molding or the like, and is arranged to extend outside the frame 71 and connect to the terminal 9. Fig. 9 As shown, by pressing the pin 78 into the connection groove formed in the terminal 9, the voice coil 75 can be electrically connected to the outside.

[0073] The sound generator of this embodiment is configured as described above. The sound generator configured in this way is arranged outside the vehicle cabin, and more specifically, is arranged inside the front bumper of the vehicle in a manner such that the emission hole 61 side is located on the front side of the vehicle. When the voice coil 75 is energized based on the sound source signal from the outside of the sound generator, the diaphragm 72 moves along the Figure 2 , Figure 7 The sound is vibrated in the vibration direction shown, and sound is emitted from the sound emitting body 7. The sound is emitted to the outside from the emission hole 61 through the first space 4, the sound emission hole 25, and the sound emission space 6. Thus, even a vehicle with a quiet running sound such as an electric car can generate an alarm sound from the sounder to notify the surroundings of the approach of the vehicle.

[0074] In addition, as one of the manufacturing processes of the sound generator, an airtightness test process is performed. When the airtightness test process is performed, a pressure difference is generated between the first space 4 and the second space 5. Specifically, the second space 5 is pressurized by sending air from the discharge hole 61 through the vent hole 241, so that the pressure in the second space 5 is higher than the pressure in the first space 4. As a result, Fig.10 , Fig.11 As shown, due to the deformation of the spring portion 724 , the inner peripheral portion 721 and the outer peripheral portion 722 of the diaphragm 72 are displaced toward the first space 4 , and the diaphragm 72 expands and deforms toward the first space 4 .

[0075] At this time, the deformed diaphragm 72 contacts the stopper 261, thereby limiting the deformation of the diaphragm 72. That is, the stopper 261 disposed inside the housing 1 replaces the clamp for pressing the diaphragm 72, thereby suppressing the warping and deformation of the diaphragm 72. Therefore, the airtightness test can be performed without using a clamp for pressing the diaphragm 72. In addition, when the diaphragm 72 contacts the stopper 261, the circular end portion 723 abuts against the cylindrical portion 261a, and the outer peripheral portion 722 abuts against the inclined portion 261b, but the inner peripheral portion 721 with low strength is located on the inner side of the cylindrical portion 261a and does not contact the stopper 261. Therefore, the diaphragm 72 can be protected from damage.

[0076] In the sound generator of such a structure, since the protection wall 22 is provided to cover the sound emission hole 25, the sound is output from the emission hole 61 through the sound emission space 6 constituted by the protection wall 22, the vertical wall 23, and the partition wall 24. That is, the sound emitted by the sound emitting body 7 can be output from one direction. Therefore, it is possible to suppress the sound from being emitted in an unnecessary direction, and it is possible to suppress the unnecessary sound from penetrating or propagating into the vehicle cabin.

[0077] Furthermore, the protective wall 22 is provided to cover the sound emitting hole 25 at the front position of the sound generator, that is, in the vibration direction of the diaphragm 72. Therefore, it is not necessary to ensure a space that serves as a passage for sound at a position adjacent to the protective wall 22 in the installation space of the sound generator on the vehicle. That is, the vehicle component can be installed close to the protective wall 22, and the sound generator can be arranged even in a narrow space of the vehicle. Therefore, it is possible to realize a sound generator that can be arranged close to the vehicle component at the front position.

[0078] In addition, in the sound generator of the structure of the present embodiment, the box body 1 can be formed by molding. For example, the box body 1 can be formed by resin molding using a lower mold for forming the outer wall surface of the protective wall 22 and the vertical wall 23 of the box body 1, an upper mold for forming the inner wall surface of the base cylinder 21 or the partition wall 24, and a sliding mold for forming the sound-releasing space 6. Therefore, one end side of the base cylinder 21 needs to be covered with the shell 3, but the other end side is covered by the protective wall 22, so it is not necessary to cover this part with a cover body or the like. Therefore, the box body 1 can be formed by two components, the base 2 and the shell, which can reduce the number of components and thus reduce the product cost.

[0079] (Second Embodiment)

[0080] The second embodiment is described below. This embodiment is different from the first embodiment in that the shape of the sound emission hole 25 is changed, and the other structures are the same as the first embodiment, so only the parts different from the first embodiment will be described.

[0081] like Fig.12 and Fig.13As shown, in this embodiment, the sound emitting hole 25 is formed by a plurality of circular through holes formed in the partition wall 24. The circular through holes constituting the sound emitting hole 25 are formed radially from the center of the sound emitting area and rotationally symmetrically. In addition, the portion of the partition wall 24 where the sound emitting hole 25 is not formed is formed as a beam portion 26. In the portion of the partition wall 24 corresponding to the cylindrical portion 261a of the stopper 261, the sound emitting hole 25 is not formed, but the beam portion 26 is formed, and the cylindrical portion 261a is formed in this portion.

[0082] In addition, the stopper 261 may include the inclined portion 261 b described in the first embodiment, but in the case of the present embodiment, the stopper 261 does not include the inclined portion 261 b.

[0083] In this way, the sound-releasing hole 25 may also be formed by a circular through hole. As in the first embodiment, a resonance effect may be obtained and a resonance frequency may be adjusted based on the shape, size, and layout of the sound-releasing hole 25. Therefore, the shape, size, and layout of the sound-releasing hole 25 may be adjusted arbitrarily, or may be formed by a plurality of circular through holes as shown in this embodiment.

[0084] (Third Embodiment)

[0085] The third embodiment is described below. This embodiment is different from the first embodiment in that the shape of the sound emission hole 25 is changed, and the other structures are the same as those of the first embodiment, so only the parts different from the first embodiment will be described.

[0086] like Fig.14 and Fig.15 As shown, in this embodiment, the sound emitting hole 25 is formed by opening the portion of the partition wall 24 corresponding to the sound emitting area in a circular shape. In this way, the sound emitting hole 25 may be formed corresponding to the sound emitting area.

[0087] In addition, in the case of such a structure, the stopper 261 is not provided. Therefore, in the case of airtightness detection, Fig.16 As shown, a clamp 10 having a front end portion having the same shape as the stopper 261 is used. In this case, the dimension Ya between the protective wall 22 and the one side 24a of the partition wall 24, the distance Yb ​​from the one side 24a to the circular end 723 of the diaphragm 72, and the thickness Yc of the clamp 10 are set so that the relationship satisfying the following equation holds.

[0088] (Mathematical formula 1)

[0089] Ya≥Yc≥Yb

[0090] First, when performing airtightness detection, the jig 10 needs to be inserted from the discharge hole 61 and reach the sound emission hole 25. Therefore, the thickness Yc needs to be equal to or less than the dimension Ya. In addition, when performing airtightness detection, if a slightly gap or a contacting state is set between the diaphragm 72 and the jig 10, it can contribute to the stabilization of the airtightness detection result. Therefore, the thickness Yc of the jig 10 is set to be equal to or greater than the distance Yb. Therefore, by setting at least Ya≥Yb, it can contribute to the stabilization of the airtightness detection using the jig 10 and the shortening of the detection time.

[0091] In this way, the sound emission hole 25 can also be formed by opening the part of the partition wall 24 corresponding to the sound emission area, so as to form a structure without the stopper 261. Even in this case, the airtightness detection can be performed by using the jig 10.

[0092] In addition, when performing airtightness detection, when a gap Yd is set between the diaphragm 72 and the jig 10, since the thickness Yc of the jig 10 can be reduced, the thickness of the product can be reduced, and it can be set as Ya<Yb, but preferably at least the gap Yd is equivalent to the gap Ye between the stopper 261 and the diaphragm 72.

[0093] (Fourth Embodiment)

[0094] The fourth embodiment will be described. Compared with the first embodiment and the second embodiment, the shape of the base 2 is changed. For other structures, it is the same as the first embodiment and the second embodiment. Therefore, only the parts different from the first embodiment and the second embodiment will be described. In addition, here, the case of changing the shape of the base 2 in the structure of the first embodiment is taken as an example for description, but it can also be applied to the structure of the second embodiment.

[0095] As Figures 17 to 21 shown, in this embodiment, between the protective wall 22 and one surface 24a of the partition wall 24, a support wall 231 which is part of the standing wall 23 is formed at a height equal to the distance between the protective wall 22 and the one surface 24a. The support wall 231 is linearly formed from the wall surface of the standing wall 23 opposite to the discharge hole 61 toward the discharge hole 61, and as Fig.17 and Fig.21 shown, it is formed to reach the end of the one surface 24a closest to the discharge hole 61 side. By providing this support wall 231, the protective wall 22 is connected to the one surface 24a of the partition wall 24 including the beam portion 26, so that the distance between the one surface 24a and the protective wall 22 can be stabilized at a specified distance, and the beam portion 26 can be supported relative to the partition wall 24 and the protective wall 22.

[0096] This can improve the strength of the protection wall 22 and the strength of the stopper 261 abutting against the diaphragm 72 , and stabilize the arrangement positions of the protection wall 22 and the stopper 261 . As a result, the displacement amount of the diaphragm 72 can be stabilized.

[0097] Furthermore, the support wall 231 is formed to straddle at least a portion of the emission hole 61. Therefore, when the inside of the emission hole 61 is viewed from an oblique direction through the emission hole 61, the wall surface of the beam portion 26 constituting the sound emission hole 25 on the inner side can be hidden by the support wall 231. Thus, it is possible to make it difficult to visually confirm the sound emission hole 25 from the emission hole 61.

[0098] Furthermore, since the support wall 231 is formed to partition the sound emitting space 6, the resonance frequency in the two partitioned rooms can be adjusted according to the partitioning method, thereby obtaining an acoustic effect.

[0099] In addition, in the present embodiment, the support wall 231 is formed to span the entire sound emission hole 25. However, if only one of the effects of improving the strength of the stopper 261, stabilizing the displacement of the diaphragm 72, shielding the inner side of the sound emission hole 25, and acoustic effects is to be obtained, the support wall 231 only needs to be formed to span at least a portion of the emission hole 61. However, it is preferred that the support wall 231 be formed to span the portion of the circular beam 263 that constitutes the stopper 261, and be set to a size that allows the stopper 261 to be supported by both ends of the support wall 231.

[0100] Furthermore, the support wall 231 is formed in a straight line toward the discharge hole 61, and has a shape that can be demolded when the base 2 is manufactured using a slide mold. Therefore, the base 2 can be easily molded. In addition, when the base 2 is manufactured by molding, the formation position of the beam portion 26 may vary due to manufacturing errors, but since the support wall 231 is provided, the occurrence of such manufacturing errors is also suppressed. Therefore, the molded dimensions of the beam portion 26 including the stopper 261 can also be stabilized.

[0101] In addition, in this embodiment, when viewed from the vibration direction of the diaphragm 72, the base tube 21 is not an ellipse, but an octagon with four angles of a rectangle inclined. Moreover, the vertical wall 23 is also formed in a shape along the outer shape of the base tube 21. That is, along the straight line passing through the center line of the octagon, in Fig.17 In the case where the base body tube 21 is divided by the XIX-XIX line, a vertical wall 23 is formed along one side obtained by the division. In addition, in the other side obtained by the division, a vertical wall 23 is extended from both ends of the long side direction of the base body tube 21 along the opposite short sides of the octagon, in other words, toward the release direction.

[0102] In this way, instead of forming the base tube 21 into an elliptical shape and forming the corner into an arc shape on the side opposite to the emission hole 61, the corner may be inclined to form a chamfered shape. In this way, if the corner of the base tube 21 is inclined, the shape of the sound emitting space 6 changes, and thus the acoustic effect can be changed compared to the case where the base tube 21 is formed into an elliptical shape.

[0103] In addition, the acoustic effect based on the shape of the sound emitting space 6 also changes according to the angle of the inclined portion of the corner of the base tube 21, that is, the angle formed by the inclined portion with respect to the long side of the base tube 21. Therefore, the angle of the inclined portion of the corner of the base tube 21 can be adjusted according to the desired acoustic effect.

[0104] According to one aspect of the present disclosure, the protective wall and the vertical wall protrude in a direction intersecting the axial direction compared to the base cylinder, and the protruding portion has an opposite wall 27 opposite to the protective wall, and the discharge hole is surrounded by the protective wall, the vertical wall and the opposite wall. In this structure, the discharge hole is preferably arranged in a rectangular shape with the side formed by the vertical wall as the short side direction and the side formed by the protective wall as the long side direction by setting the vertical wall to be shorter than the protective wall. In this way, the vibration direction of the diaphragm can be set to the short side direction, so that the thickness of the product can be reduced, and even if it is a rectangular shape, the opening area required to generate sound pressure can be ensured. In addition, the front end of the discharge hole in the protective wall, the vertical wall and the opposite wall can be terminated on the same plane, and the side formed by the front end constitutes the discharge surface 62. In addition, the normal direction of the discharge surface can be formed as a plane parallel to the vibration direction of the diaphragm.

[0105] In the sound emitting area, a plurality of through holes constituting emission holes are formed in the partition wall, and the beam portion 26 is formed by the area other than the emission holes.

[0106] In this way, the beam portion can be provided in the area other than the emission hole in the sound emission area, thereby preventing water spillage and flying stones from reaching the sound emitting body during driving, and preventing the sound emitting body from being damaged by contact with water or stones.

[0107] A stopper 261 is provided on the diaphragm side of the beam portion to limit displacement of the diaphragm in the vibration direction.

[0108] Thus, damage caused by excessive deformation of the diaphragm due to airtightness detection can be suppressed. The diaphragm is configured to have an inner peripheral portion 721 that is convex toward the first space side, and an outer peripheral portion 722 in the shape of a hollow frustum of a cone that expands from the outer edge of the inner peripheral portion toward the first space, and the stopper is configured to have a cylindrical portion 261a, which has the same diameter as the circular boundary portion of the inner peripheral portion and the outer peripheral portion, and protrudes from the beam portion toward the diaphragm side. In this case, a circular end portion 723 can be formed at the boundary portion, which is opposite to the cylindrical portion and is displaced the most in the vibration direction of the diaphragm when the diaphragm is displaced. By forming such a circular end portion, the cylindrical portion of the stopper can be brought into contact with a portion with high strength even in the diaphragm.

[0109] The driving portion includes: a cylindrical core portion 74, which is arranged on one side of the diaphragm; a voice coil 75, which is wound on the core portion; and a magnetic circuit portion 76, which applies a magnetic field to the voice coil to displace the core portion and the voice coil, thereby causing the diaphragm to vibrate; on the driving portion side of the circular end, one end of the core portion is fixed by an adhesive.

[0110] In this way, by fixing one end of the core to the driver portion side of the circular end portion with an adhesive, the core and the diaphragm can be integrated.

[0111] Furthermore, the beam portion may be configured to include radial beams 262 extending radially from the center of the sound radiating area and circular beams 263 arranged concentrically, with the cylindrical portion of the stopper being provided on the circular beam.

[0112] The diaphragm is characterized in that it has an inner peripheral portion 721 that is convex toward the first space side, and an outer peripheral portion 722 in the shape of a hollow frustum of a cone that expands from the outer edge of the inner peripheral portion toward the first space. In the sound emission area, the partition wall is opened to form a sound emission hole, and the dimension between one side 24a of the partition wall opposite to the protective wall and the protective wall is set to Ya, and the distance from one side of the partition wall to the circular end of the boundary between the inner peripheral portion and the outer peripheral portion of the diaphragm is set to Yb, satisfying Ya≥Yb.

[0113] In this way, the sound emission hole can be formed by opening the portion of the partition wall corresponding to the sound emission area, thereby forming a structure without a stopper. Even in this case, as long as the relationship Ya≥Yb is satisfied, the airtightness test can be performed stably in a short time by using the jig 10.

[0114] The characteristic is that the dimension between one side 24a of the partition wall facing the protective wall and the protective wall is set as Ya, the distance from one side of the partition wall to the boundary between the inner and outer peripheries of the diaphragm is set as Yb, and Ya<Yb is satisfied.

[0115] When performing airtightness detection, when a gap Yd is provided between the diaphragm and the fixture, the thickness Yc of the fixture can be reduced. Therefore, it can be set that Ya < Yb, and the thickness of the product can be reduced.

[0116] The sounding body according to one aspect of the present disclosure includes a connector 29 that intersects the vibration direction of the diaphragm and is provided along a direction parallel to the partition wall outside the standing wall. According to such a structure, even if the connector is provided, the thickness of the product can be reduced.

[0117] The standing wall is between the surface 24a of the partition wall facing the protective wall and the protective wall, and its height is equal to the distance between the surface of the partition wall facing the protective wall and the protective wall. Moreover, from the wall surface of the standing wall facing the discharge hole, there is a support portion 231 formed linearly toward the discharge hole.

[0118] By forming the support portion in this way, in addition to improving the strength of the protective wall, the stabilization of the arrangement position of the protective wall is also achieved. For example, the support portion can be formed to straddle the sound hole, or a plurality of support portions can be arranged in parallel.

[0119] (Other embodiments)

[0120] In addition, the present invention is not limited to the above embodiments, and can be appropriately changed within the scope described in the claims.

[0121] For example, although in the above embodiments, an example of the shape and layout of the sound hole 25 has been given, the shape and layout of the sound hole 25 are arbitrary and can also be other shapes and layouts. In addition, the shape of the diaphragm 72 and the shape of the stopper 261 can also be other shapes. Even in this case, by restricting the displacement of the diaphragm 72 using the stopper 261, warping, deformation, and damage of the diaphragm 72 can be suppressed.

[0122] In addition, in the above embodiments, the case where the protective wall 22 and the standing wall 23 are formed as part of the base 2, that is, the case where they are formed of one component, is taken as an example. However, this is only an example. For example, the protective wall 22 and the standing wall 23 can also be separate components and be integrated by being assembled on the base 2.

[0123] Furthermore, since the sound emission direction can be limited by forming a structure in which the sound emission area where the sound emitter 7 is arranged is covered by the protective wall 22, the sound emission direction can be limited to two directions instead of one direction. For example, by providing openings of the protective wall 22 and the vertical wall 23 at two positions, the sound emission direction can be set to two directions. In this case, since the sound emission direction can be limited to two directions, the noise in the vehicle cabin can also be reduced, and since the sound emission area where the sound emitter 7 is arranged is covered by the protective wall 22, the automobile parts can be arranged close to the front position of the sound emitter.

[0124] In addition, although in the fourth embodiment described above, a structure is set to form only one support portion 231 across the sound emission hole 25, a plurality of support walls 231 may be formed in parallel. The number and formation position of the support walls 231 are arbitrary, and the length of each support wall 231 is also arbitrary. In this case, the plurality of support walls may be set to the same length or different lengths. As the number of support walls 231 increases, the stabilization effect of the displacement amount of the diaphragm 72 is enhanced, and the sound emission hole 25 can be made difficult to be visually confirmed.

[0125] In addition, the fourth embodiment described above takes the case where the support wall 231 is provided in contrast to the structure having the stopper 261 as in the first and second embodiments as an example, but it can also be applied to a structure not having the stopper 261 as in the third embodiment. However, in this case, the stabilization effect of the stopper 261 cannot be obtained.

Claims

1. A sound generator that generates sound by vibrating a diaphragm (72), the sound generator comprising: A sound-generating body (7) comprising the diaphragm and a driving unit (73) for generating sound by vibrating the diaphragm when electricity is supplied; as well as A base (2) includes a base tube (21) accommodating the sound-generating body and a partition wall (24), wherein the partition wall is arranged at one end side of the axial direction of the base tube, and the area where the sound-generating body is arranged is used as a sound-generating area, and a sound-generating hole (25) is formed in the sound-generating area to guide the sound generated by the sound-generating body, and the interior of the base tube is divided into a first space (4) and a second space (5) by the diaphragm and the partition wall. In the vibration direction of the diaphragm, there are a protective wall (22) arranged to be spaced apart from the partition wall and cover the sound emitting area, and a vertical wall (23) connecting the protective wall and the base tube part. A sound release space (6) is formed between the protective wall, the vertical wall and the partition wall and is connected to the first space through the sound release hole. The protective wall and the vertical wall are opened in at least one direction to form a release hole (61) for outputting the sound guided from the first space to the sound release space through the sound release hole.

2. The sound generator according to claim 1, wherein The protective wall and the vertical wall protrude in a direction intersecting the axial direction relative to the base body tube portion, and the protruding portion has an opposing wall (27) opposing the protective wall. The discharge hole is surrounded by the protection wall, the standing wall and the opposing wall.

3. The sound generator according to claim 2, wherein: The discharge hole is formed into a rectangular shape with one side formed by the standing wall being shorter than the protection wall and one side formed by the protection wall being longer.

4. The sound generator according to claim 3, wherein: The front ends of the protection wall, the vertical wall and the opposite wall constituting the discharge hole terminate on the same plane, and a surface formed by the front ends constitutes a discharge surface (62).

5. The sound generator according to claim 4, wherein: The normal direction of the emission surface is formed as a plane parallel to the vibration direction of the diaphragm.

6. The sound generator according to claim 1, wherein In the sound emitting area, a plurality of through holes constituting the sound emitting holes are formed in the partition wall, and a beam portion (26) is formed by an area other than the sound emitting holes.

7. The sound generator according to claim 6, wherein: A stopper (261) is provided on the diaphragm side of the beam portion to limit displacement of the diaphragm in the vibration direction.

8. The sound generator according to claim 7, wherein: The diaphragm has an inner peripheral portion (721) convex toward the first space and an outer peripheral portion (722) in the shape of a hollow truncated cone extending from the outer edge of the inner peripheral portion toward the first space; The stopper has a cylindrical portion (261a) having the same diameter as a circular boundary portion between the inner peripheral portion and the outer peripheral portion and protruding from the beam portion toward the diaphragm side.

9. The sound generator according to claim 8, wherein A circular end portion (723) is formed at the boundary portion, the circular end portion being opposite to the cylindrical portion and being displaced the most in the vibration direction of the diaphragm when the diaphragm is displaced.

10. The sound generator according to claim 9, wherein The driving unit comprises: A cylindrical core (74) disposed on one side of the diaphragm; a voice coil (75) wound around the core; and a magnetic circuit portion (76) which applies a magnetic field to the voice coil to displace the core and the voice coil, thereby causing the diaphragm to vibrate; One end of the core is fixed to the driving portion side of the circular end portion by an adhesive.

11. The sound generator according to any one of claims 8 to 10, wherein: The beam portion includes radial beams (262) extending radially from the center of the sound emitting area and circular beams (263) arranged in concentric circles. The cylindrical portion is disposed on the circular beam.

12. The sound generator according to any one of claims 1 to 6, wherein: The diaphragm has an inner peripheral portion (721) convex toward the first space and an outer peripheral portion (722) in the shape of a hollow truncated cone extending from the outer edge of the inner peripheral portion toward the first space. In the sound emitting area, the partition wall is opened to form the sound emitting hole. The dimension between the side (24a) of the partition wall opposite to the protection wall and the protection wall is defined as Ya, Let Yb be the distance from the one surface of the partition wall to the boundary between the inner peripheral portion and the outer peripheral portion of the diaphragm. Satisfies Ya≥Yb.

13. The sound generator according to any one of claims 8 to 10, wherein: The dimension between the side (24a) of the partition wall opposite to the protection wall and the protection wall is defined as Ya, Let Yb be the distance from the one surface of the partition wall to the boundary between the inner peripheral portion and the outer peripheral portion of the diaphragm. Meet Ya <Yb。 14. The sound generator according to any one of claims 1 to 10, comprising a connector (29) which is arranged on the outside of the vertical wall in a direction parallel to the partition wall and intersects with the vibration direction of the diaphragm.

15. The sound generator according to claim 1, wherein Between the side (24a) of the partition wall opposite to the protective wall and the protective wall, the height of the vertical wall is equal to the distance between the side of the partition wall opposite to the protective wall and the protective wall, and the vertical wall has a supporting portion (231) formed in a straight line from the wall surface of the vertical wall opposite to the discharge hole toward the discharge hole.

16. The sound generator according to claim 15, wherein The support portion is formed to straddle the sound emission hole.

17. A sound generator according to claim 15 or 16, wherein: A plurality of the support portions are arranged in parallel between a surface (24a) of the partition wall that faces the protection wall and the protection wall.

18. A method for manufacturing a sound generator, which is a method for manufacturing a sound generator that generates sound by vibrating a diaphragm (72), wherein the method comprises preparing a sound generator, the sound generator comprising: A sound-generating body (7) comprising the diaphragm and a driving unit (73), wherein the diaphragm comprises an inner peripheral portion (721) and an outer peripheral portion (722) in the shape of a hollow truncated cone extending outward from the outer edge of the inner peripheral portion, and the driving unit generates sound by vibrating the diaphragm through power supply; A base (2) comprising a base tube (21) accommodating the sound-generating body and a partition wall (24), wherein the partition wall is arranged at one end side of the axial direction of the base tube and uses the area where the sound-generating body is arranged as a sound-generating area, and a sound-generating hole (25) is formed through the opening of the sound-generating area to guide the sound generated by the sound-generating body; the interior of the base tube is divided into a first space (4) and a second space (5) by the diaphragm and the partition wall; A protective wall (22) configured to cover the sound reproduction area with a gap between the protective wall and the partition wall in the vibration direction of the diaphragm; and a vertical wall (23) connecting the protective wall and the base tube portion, A sound release space (6) is formed between the protective wall, the vertical wall and the partition wall and is connected to the first space through the sound release hole, and a release hole (61) is formed by opening the protective wall and the vertical wall in at least one direction, and the release hole outputs the sound guided from the first space to the sound release space through the sound release hole; The dimension between the side (24a) of the partition wall opposite to the protection wall and the protection wall is defined as Ya, Let Yb be the distance from the one surface of the partition wall to the boundary between the inner peripheral portion and the outer peripheral portion of the diaphragm. Satisfy Ya>Yb; As an airtightness detection step, a jig (10) is inserted from the sound release hole and arranged in the sound release hole, so that the pressure of the second space is made higher than the pressure of the first space, thereby expanding the diaphragm toward the first space.

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