Speaker

Abstract

To provide a speaker capable of enhancing a heat dissipation effect of a circuit part fixed to a support body.SOLUTION: In a speaker 1, a rear part of a vibration part 2 is covered by a cover member 13 and a duct 14 is arranged on the cover member 13. In the cover member 13, a recessed part 13c is formed along a circular arcuate trajectory with a center axis O as a center and an air passage 16 is formed inside the recessed part 13c. A circuit part 30 is arranged on an outer surface of the cover member 13 and a heat sink 33 arranged inside the air passage 16 is connected to the circuit part 30 so as to be thermally conductive. An air flow in the air passage 16 is accelerated by the vibration of the vibration part 2 so as to enhance a heat dissipation effect from the heat sink 33.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a speaker provided with a circuit section having heat-generating electronic elements, and to a speaker in which the heat dissipation effect of the circuit section is improved. [Background technology]

[0002] In the speaker described in Patent Document 1, a frame is fixed to the top of a magnetic circuit, and a vibration system consisting of a diaphragm and a coil is supported inside the frame by edges and dampers so that it can vibrate freely. A holding member with a large heat dissipation area is fixed to the top surface of the center pole of the magnetic circuit, and an amplifier is fixed on top of the holding member. This invention is that when the diaphragm vibrates with a large amplitude in the low frequency band and the air volume above the diaphragm increases, it is possible to increase the heat dissipation and cooling effect of the amplifier exposed to the outside air above the diaphragm.

[0003] The acoustic device described in Patent Document 2 has a frame member provided with a driver cone and a drive motor structure that vibrates the driver cone. An amplifier assembly is provided in a volume portion in front of the driver cone. The amplifier assembly has a heat sink and an amplifier cover that is in thermal contact with the heat sink and holds the amplifier. This invention also has the idea that when the driver cone vibrates at an audible frequency, air movement occurs in the volume portion due to pressure waves that become sound waves, making it easier to dissipate heat from the amplifier assembly. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 1-149191 [Patent Document 2] JP 2004-120747 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the inventions described in Patent Documents 1 and 2, when the diaphragm or driver cone vibrates, a near-laminar airflow is generated in front of it, and this near-laminar airflow simply moves back and forth within a wide area. Because the amplifier is simply exposed and placed in the space in front of the diaphragm or driver cone, even if the near-laminar airflow acts on the amplifier, it is unable to sufficiently agitate the air around the amplifier, which makes it easier for heat to stagnate around the amplifier, limiting the improvement of the heat dissipation effect.

[0006] SUMMARY OF THE PRESENT DISCLOSURE ... The present invention is intended to solve the above-mentioned problems in the conventional art, and has an object to provide a speaker that can improve the heat dissipation effect of the circuit section. [Means for solving the problem]

[0007] The present invention provides a speaker including a vibration section including a diaphragm and a voice coil, a magnetic circuit section that applies a magnetic field to the voice coil, and a support that supports the vibration section and the magnetic circuit section, The vibration portion is provided with a vibration plate having a tapered portion, the support includes a cover member that covers the vibration unit from one side in a vibration direction of the vibration unit, and a duct that connects a space between the vibration unit and the cover member to an external space outside the cover member, The cover member is provided with a cover tapered portion that faces the tapered portion and is inclined in the same direction as the tapered portion, and a recess that is recessed in a direction away from the vibration portion, in a part of an area covering the vibration portion, the recess being formed to be continuous with the cover tapered portion at a position farther away from the center of the vibration portion than the cover tapered portion and surrounding the center, A distance in the vibration direction between the vibration portion and the cover member in the recess is wider than the distance in the cover tapered portion, and an air flow path is formed inside the recess, Air Flow Path is connected to the inside of the duct, The air conditioner is characterized in that a circuit section provided on the outside of the cover member is connected to a heat sink at least a portion of which is exposed within the air flow path.

[0009] In the speaker of the present invention, for example, the air flow path is continuous and surrounds the center of the vibration section, and the duct is provided at a position offset from the center.

[0010] Alternatively, in the speaker of the present invention, the duct is provided at a position offset from the center of the vibration section, and the air flow path passes through the center.

[0011] Alternatively, in the speaker of the present invention, the duct is provided in the center of the vibration part, and the air flow path extends from the outer periphery side of the vibration part to the center.

[0013] In the speaker of the present invention, the heat sink has a groove, It is preferable that the groove portion penetrates the air flow passage in a direction toward the duct.

[0014] The speaker of the present invention can be configured such that the circuit section has a circuit board fixed to the outer surface of the cover member and a circuit element mounted on the circuit board, and the heat sink is connected to the circuit section through an opening formed in the cover member. Effect of the Invention

[0015] The speaker of the present invention is provided with a cover member that covers the diaphragm from one side in the vibration direction of the vibration part. An air flow path that leads to a duct is formed in the closed space between the diaphragm and the cover member, and a heat sink is disposed in this air flow path. When the vibration part vibrates, an airflow is generated in the air flow path, so that heat can be effectively dissipated from the heat sink located in the air flow path. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing an external appearance of a speaker according to a first embodiment of the present invention, viewed from the rear; [Diagram 2] FIG. 2 is an exploded perspective view showing the speaker of the first embodiment from the rear; [Diagram 3] FIG. 3 is a cross-sectional view of the speaker according to the first embodiment taken along line III-III in FIG. [Figure 4] 1 is a cross-sectional view showing a speaker according to a second embodiment of the present invention; [Diagram 5] FIG. 11 is a rear perspective view showing the appearance of a speaker according to a third embodiment of the present invention; [Figure 6] 6 is a cross-sectional view of the speaker according to the third embodiment taken along line VI-VI in FIG. 5 ; [Figure 7] FIG. 13 is a rear perspective view showing the appearance of a speaker according to a fourth embodiment of the present invention; [Figure 8] 8 is a cross-sectional view of the speaker according to the fourth embodiment taken along line VIII-VIII in FIG. 7; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In the first to fourth embodiments of the present invention described below, the Y1-Y2 direction is the vibration direction of the vibration unit 2. In each embodiment, the Y1 direction is the front, which is the sound-generating direction, and the Y2 direction is the rear. The speaker in each embodiment is for vehicle mounting. As an example of installation of the speaker, the front (Y1 direction) which is the sound-generating direction is directed toward the inside of the vehicle, and the duct 14 provided at the rear is fixed to the vehicle body so as to communicate with the space outside the vehicle. In another installation example, the speaker is disposed in a space outside the vehicle cabin, such as an engine room or a trunk room, and the duct 14 is directed toward the inside of the vehicle cabin. In this case, the Y2 direction is the front, which faces the inside of the vehicle cabin, which is the sound-generating direction, and the Y1 direction is the rear, which faces the outside of the vehicle.

[0018] (First embodiment) In the speaker 1 of the first embodiment of the present invention shown in Figures 1 to 3, the lower side in the figure is the front (Y1 direction) and the sound generation direction, and the upper side in the figure is the rear (Y2 direction). In the second to fourth embodiments described in Figure 4 and subsequent figures, the lower side in the figure is the front (Y1 direction) and the sound generation direction, and the upper side in the figure is the rear (Y2 direction).

[0019] The speaker 1 shown in FIG. 1 to FIG. 3 has a support 10. As shown in FIG. 2, the support 10 has a front frame 11 located at the front, a rear frame 12 located at the rear, a cover member 13 stacked further rearward of the rear frame 12, and a duct 14 provided on the cover member 13. The duct 14 is formed integrally with the cover member 13. Alternatively, the duct 14 is formed separately from the cover member 13 and fixed to the cover member 13. A diaphragm 3 is provided inside the speaker 1. The diaphragm 3 has a circular planar shape projected from the front or rear, and has a tapered portion whose diameter gradually increases toward the front (Y1 direction) which is the sound generation direction. The main parts of the front frame 11, the rear frame 12, and the cover member 13 have a circular planar shape projected from the front or rear. The diaphragm 3, the front frame 11, the rear frame 12, and the cover member 13 may have an elliptical or oblong planar shape projected from the front or rear.

[0020] 3, multiple openings 11a are formed in the front frame 11, and sound pressure caused by vibration of the diaphragm 3 can flow forward (in the Y1 direction) through the openings 11a. Multiple openings 12a are also formed in the rear frame 12. The cover member 13 covers the entire space behind the vibrating part 2, including the diaphragm 3, except for the internal space of the duct 14, so as to close it off.

[0021] As shown in FIG. 3, the vibration section 2 has the diaphragm 3, edge member 4, bobbin 5, and cap member 6. In each of the figures showing the respective embodiments, a central axis O is shown extending in the front-rear direction (the vibration direction of the vibration section 2) through the center of the vibration section 2. The edge member 4 is made of an elastically deformable sheet material and is formed with a curved semicircular cross section. The planar shape of the edge member 4 seen from the front or rear is a ring shape, and the inner peripheral portion 4a is bonded to the outer peripheral edge 3a of the vibration section 3. The outer peripheral portion 4b of the edge member 4 is sandwiched between the outer peripheral portion of the front frame 11 and the outer peripheral portion of the rear frame 12, and the outer peripheral portion of the front frame 11, the outer peripheral portion of the rear frame 12, and the outer peripheral portion of the cover member 13 are fixed by screws or the like. The bobbin 5 is provided in the center of the speaker 1, and the inner peripheral edge 3b of the diaphragm is bonded and fixed to the outer peripheral surface of the bobbin 5. The opening of the bobbin 5 facing rearward (Y2 direction) is covered with the cap member 6.

[0022] A damper member 7 is provided inside the speaker 1. The damper member 7 is made of an elastically deformable sheet material and has a corrugated cross section. Two damper members 7 are provided parallel to each other in the front-rear direction, and each of the outer periphery 7a is adhered and fixed to the rear frame 12, and the inner periphery 7b is adhered and fixed to the outer periphery surface of the bobbin 5. In the vibration section 2, the diaphragm 3, bobbin 5, and cap member 6 are supported by the edge member 4, which is a part of the vibration section 2, and the damper member 7 so as to be able to vibrate freely in the front-rear direction.

[0023] As shown in FIG. 3, a voice coil 8 is wound around the outer periphery of the front end (Y1 direction) of the bobbin 5. The voice coil 8 is also a part of the vibration unit 2. The voice coil 8 and the magnetic circuit unit 20 constitute a magnetic drive unit. The magnetic circuit unit 20 has a front yoke 21, a center ball 22, and a rear yoke 24. The front yoke 21, the center pole 22, and the rear yoke 24 are made of a magnetic material. A ring-shaped magnet 23 is sandwiched between the front yoke 21 and the rear yoke 24. A magnetic gap is formed at the opposing portion between the outer periphery of the center pole 22 and the inner periphery of the rear yoke 24, and the voice coil 8 is located within the magnetic gap. Due to the magnetic field generated by the magnet 23, a magnetic flux passing through the magnetic gap crosses the voice coil 8.

[0024] As shown in Figs. 1 and 2, the cover member 13 has a ring-shaped region centered on the central axis O as a tapered cover tapered portion 13a. As shown in Fig. 3, the cover tapered portion 13a is inclined in the same direction as the tapered portion of the diaphragm 3, and the tapered portion of the diaphragm 3 and the cover tapered portion 13a face each other almost parallel to each other. The cover member 13 has a central region surrounded by the cover tapered portion 13a as a raised portion 13b that rises toward the rear. A recess 13c that is recessed toward the rear (Y2 direction), which is a direction away from the vibration portion 2, is formed on the inner surface of the cover member 13 facing forward (Y1 direction). The recess 13c is formed along a circular arc locus centered on the central axis O on the outer periphery of the cover tapered portion 13a.

[0025] 3, a space 15 is formed between the vibration part 2 and the cover member 13. In the vibration part 2, an edge member 4 is provided on the outer periphery of the vibration plate 3, and a cap member 6 that covers the opening of the bobbin 5 is provided in the center of the vibration plate 3. Therefore, the space 15 behind the vibration part 2 (Y2 direction) is isolated from the space in front of the vibration part 2 (Y1 direction). The internal space of the duct 14 communicates with the space 15, and the space 15 is isolated from the external space except for the internal space of the duct 14.

[0026] As shown in Fig. 3, in the region in the space 15 where the recess 13c is formed, the front-rear distance L1 (distance in the vibration direction of the vibration part 2) between the rear surface facing rearward (Y2 direction) of the vibration part 2 and the front surface facing forward (Y1 direction) of the cover member 13 is wider than the front-rear distance in another part of the space 15. In the embodiment shown in Fig. 3, the other part is the opposing part between the tapered part of the vibration plate 3 and the cover tapered part 13a. The front-rear distance L1 in the part where the recess 13c is formed is wider than the front-rear distance L2 in this opposing part (distance in the vibration direction of the vibration part 2).

[0027] In the space 15 between the vibration part 2 and the cover member 13, the region of the interval L1 formed along a circular arc locus centered on the central axis O is the air flow path 16. In this specification, only the internal space of the recess 13c of the cover member 13 can be defined as the air flow path 16. This is the air flow path in the narrow sense. Also, the internal space of the recess 13c, the internal space of the edge member 4 having a semicircular cross section, and the entire space sandwiched between the recess 13c and the edge member 4 from the front and rear (space of interval L1) can be defined as the air flow path 16. This is the air flow path in the broad sense. Alternatively, the region excluding the internal space of the edge member 4 from the region of interval L1 can be defined as the air flow path 16. Also, in a configuration in which the recess 13c is not provided in the cover member 13, the region excluding the internal space of the recess 13c from the region of interval L1, that is, the internal space of the edge member 4 and the space continuous with it to the rear, functions as the air flow path 16.

[0028] 1 and 3, air flow path 16 extends along a circular arc locus centered on central axis O in an area of ​​a constant radius from central axis O. Air flow path 16 communicates with the internal space of duct 14. By forming air flow path 16 along a circular arc locus with a constant radius centered on central axis O, the viscous resistance generated by space 15 can be made to act evenly on vibration part 2 when vibration part 2 vibrates back and forth.

[0029] 2, the cover member 13 has an opening 18 formed in a region where the recess 13c is formed and at a position close to the duct 14. In the region where the opening 18 is formed, a circuit section 30 is installed on the outer surface of the cover member 13 facing rearward. The circuit section 30 has a circuit board 31, and an electronic element (electronic component) 32 is mounted on the surface of the circuit board 31 facing rearward. The circuit section 30 constitutes an amplifier, and the electronic element 32 includes a heat-generating electronic element (heat-generating electronic component). The outer surface of the cover member 13 on which the circuit section 30 is installed is flat, allowing the circuit section 30 to be stably installed.

[0030] As shown in FIG. 3, in the internal space in front of the recess 13c, at least a part of the heat sink 33 is provided in the portion where the opening 18 is formed. The heat sink 33 is formed of a metal material with high thermal conductivity such as aluminum or an aluminum alloy. A heat conducting portion in contact with a heat generating electronic element is formed of a metal layer or the like on the surface facing the front (Y1 direction) of the circuit board 31, and the heat sink 33 is connected to this heat conducting portion, so that the heat sink 33 and the circuit portion 30 are connected to each other through the inside of the opening 18 so as to be capable of thermal conduction. As shown in FIG. 2 and FIG. 3, the heat sink 33 has a plurality of grooves 33a formed therein, which penetrate in a direction intersecting the front-rear direction (Y1-Y2 direction). Inside the recess 13c, the grooves 33a penetrate and extend in a direction along the air flow of the air flow passage 16, i.e., in a direction toward the duct 14.

[0031] Next, the operation of the speaker 1 will be described. In the sound generation operation, a driving current is applied to the voice coil 8 based on an audio signal output from an audio amplifier. In the magnetic circuit section 20, a driving magnetic flux circulates based on the magnetic field of the magnet 23, and the driving magnetic flux crosses the voice coil 8 located in the magnetic gap. The electromagnetic force excited by the driving magnetic flux crossing the magnetic gap and the driving current of the voice coil 8 causes the vibration section 2 including the diaphragm 3, the edge member 4, the bobbin 5, and the cap member 6 to vibrate in the front-rear direction. The sound pressure generated in front of the diaphragm 3 (Y1 direction) mainly due to the vibration in the front-rear direction of the diaphragm 3 passes through the opening 11a of the front frame 11 and is given to the inside of the vehicle. An air pressure in the opposite phase to the sound pressure is generated behind the diaphragm 3 (Y2 direction), and this air pressure is discharged to the outside through the internal space of the duct 14 from the space 15 between the vibration section 2 and the cover member 13. This suppresses interference between the sound pressure emitted forward (Y1 direction) and the air pressure in the opposite phase thereto.

[0032] In the space 15 between the vibrating part 2 and the cover member 13, the air pressure changes based on the vibration of the vibrating part 2 in the front-rear direction, and this change in air pressure generates an air flow. In the space 15, the front-rear distance L2 is narrow at the opposing portion between the tapered part of the diaphragm 3 and the cover tapered part 13a, and the front-rear distance L1 is wide in the air flow path 16. Therefore, the air flow tends to concentrate in the air flow path 16 of the distance L1 due to the pressure change in the space of the distance L2 where the tapered part is provided.

[0033] When the vibration part 2 moves backward (Y2 direction), the air compressed in the space of the tapered part with the narrow gap L2 flows into the air flow path 16, a flow is generated in the air flow path 16, and the air flow is released from the duct 14 to the external space. When the vibration part 2 moves forward (Y1 direction), the volume of the space of the tapered part with the gap L2 expands and the air pressure decreases, so that the air in the external space flows from the air flow path 16 to the tapered part through the duct 14. As a result, in the space 15, an air flow is easily generated along the air flow path 16 inside the recess 13c along the circular arc locus, and the heat sink 33 located in the air flow path 16 is exposed to the air flow. The heat generated in the circuit part 30 is released into the external space behind the cover member 13, and is transferred to the air flow of the air flow path 16 through the heat sink 33, and is released to the external space through the internal space of the duct 14. In the air flow path 16, the grooves 33a of the heat sink 33 extend in a direction along the air flow in the air flow path 16, so that the heat dissipation effect from the heat sink 33 to the inside of the air flow path 16 can be improved.

[0034] 2, the cover member 13 has a recess 13c formed continuous with the cover tapered portion 13a, i.e., an air flow path 16 formed continuous with the space in the tapered portion. The air flow path 16 is formed along a circular arc trajectory centered on the central axis O and communicates with the inside of the duct 14 located at the outer periphery off the central axis O. In this structure, the air flow is likely to concentrate in the air flow path 16 of the circular arc trajectory due to pressure changes in the space of the tapered portion, and this air flow communicates with the outside space through the internal space of the duct 14 located in the outer periphery region. At least a portion of the heat sink 33 is located within this air flow path 16, and is also located in a position close to the duct 14, so that heat can be easily dissipated from the heat sink 33.

[0035] In the second to fourth embodiments, parts having the same functions as those in the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals even if their shapes are different, and detailed description thereof will be omitted.

[0036] Second embodiment In the speaker 101 of the second embodiment shown in FIG. 4, the support 10 is composed of a front frame 11 and a cover member 13, and a rear frame 12 is not provided. The outer peripheral portion 4b of the edge member 4 constituting the vibrating portion 2 is sandwiched and fixed between the outer peripheral portion of the front frame 11 and the outer peripheral portion of the cover member 13. The diaphragm 3 constituting the vibrating portion 2 has a tapered portion whose diameter gradually increases toward the rear (Y2 direction), and the inclination direction of the tapered portion of the diaphragm 3 is opposite to that of the first embodiment in the front and rear. The damper member 7 is located forward (Y1 direction) of the diaphragm 3. The cap member 6 covering the rear opening of the bobbin 5 is dome-shaped with the protruding side facing rearward.

[0037] The cover member 13 has a dome-shaped raised portion 13b at the center, which is raised to follow the rearward bulge of the cap member 6. The cover member 13 has a tapered cover tapered portion 13a formed on the outer periphery of the raised portion 13b and centered on the central axis O. The inclination direction of the cover tapered portion 13a is the same as the inclination direction of the tapered portion of the diaphragm 3. In addition, the cover member 13 has a recessed portion 13c formed on the inner surface facing the front, which is recessed toward the rear on the outer periphery side of the cover tapered portion 13a. As in the first embodiment, the recessed portion 13c is continuous around almost the entire circumference along a circular arc locus centered on the central axis O. The cover member 13 has a duct 14 formed at a position off the central axis O, and the inside of the recessed portion 13c is connected to the internal space of the duct 14.

[0038] As shown in Fig. 4, in speaker 101, recess 13c of cover member 13 is formed on the inner circumferential side closer to central axis O than the portion facing edge member 4, and in space 15, the region where recess 13c faces diaphragm 3 forms air flow path 16. The front-rear distance of air flow path 16 is L1. On the center side of recess 13c, the front-rear distance L2 between the tapered portion of diaphragm 3 and cover tapered portion 13a is narrow, and the front-rear distance between the portion where cap member 6 faces dome-shaped protrusion 13b is also approximately L2. Therefore, front-rear distance L1 of air flow path 16 is wider than any other region in space 15.

[0039] Further, a heat sink 33 is provided inside the air flow path 16 at a position close to the duct 14, and a circuit section 30 provided on the outer surface of the cover member 13 is connected to the heat sink 33 so as to be capable of thermal conduction.

[0040] In the speaker 101 of the second embodiment, in the space 15 where the vibrating part 2 and the cover member 13 face each other, the distance L1 in the front-rear direction of the air flow path 16 is wide, and the distance L2 in the front-rear direction of the space 15 is narrow in the entire area inside. Therefore, when the vibrating part 2 vibrates back and forth, the pressure changes greatly in the central part where the distance L2 is narrow, where the cover tapered part 13a and the raised part 13b are formed, and a fast air flow is formed from the air flow path 16 to the internal space of the duct 14. This can improve the heat dissipation effect from the heat sink 33.

[0041] Third embodiment The speaker 201 of the third embodiment shown in Fig. 5 and Fig. 6 has the same basic structure as the speaker 101 of the second embodiment shown in Fig. 4. The cover member 13 is provided with a cover tapered portion 13a whose diameter gradually increases toward the rear, and the cover tapered portion 13a and the tapered portion 13a of the diaphragm 3 face each other substantially parallel to each other. The cover member 13 has a recess 13c formed at a location closer to the central axis O than the edge member 4, i.e., at a location midway in the radial direction of the cover tapered portion 13a, and further has a central recess 13d formed at the center. As shown in Fig. 5, the recess 13c is formed along a circular arc locus centered on the central axis O, and the central recess 13d passes through the central axis O and extends linearly in the diameter direction. The duct 14 is provided at a position deviated from the central axis O. In addition, in the cover member 13, a raised portion 13b is formed at the boundary between the cover tapered portion 13a and the central recessed portion 13d, and the raised portion 13b is formed in a dome shape facing rearward so as to follow the shape of the cap member 6.

[0042] As shown in Fig. 5, the closed end 13e of the recess 13c along the arc trajectory is away from the duct 14, and the recess 13c does not communicate directly with the duct 14. On the side opposite to where the duct 14 is provided with respect to the central axis O, the middle part of the arc-shaped recess 13c communicates with the central recess 13d. And the central recess 13d communicates with the internal space of the duct 14.

[0043] As shown in Fig. 6, in the space 15 between the vibrating part 2 and the cover member 13, the front-back facing interval L1 between the recess 13c and the diaphragm 3 is wide, and the region where the recess 13c and the diaphragm 3 face each other forms an air flow path 16. Or only the internal space of the recess 13c can be defined as the air flow path 16. The front-back interval L2 of the region where the cover taper part 13a, which is another part in the space 15, faces is narrower than the L1, and the front-back distance of the region where the raised part 13b faces is also equal to the L2. The front-back interval L3 between the central recess 13d and the cap member 6, which is a part of the vibrating part 2, is also wide, and the region where the central recess 13d and the cap member 6 face each other forms a central air flow path 116. Or only the internal space of the central recess 13d can be defined as the central air flow path 116. In the space 15, the front-back intervals are wide in the order of L2 < L1 < L3.

[0044] A heat sink 33 is provided at a position approaching the duct 14 inside the central air flow path 116, and a circuit part 30 installed on the outer surface of the cover member 13 is connected to the heat sink 33 in a thermally conductive manner.

[0045] In the speaker 201 of the third embodiment, when the vibrating section 2 vibrates back and forth, in the space 15 between the vibrating section 2 and the cover member 13, the pressure change becomes large in the portion where the interval L2 where the cover tapered section 13a and the raised section 13b are formed is short, and the air flow concentrates inside the air flow path 16 and the central air flow path 116, which are spaced apart in the front-rear direction by a large amount. As shown in Fig. 6, on the outer circumferential side of the recess 13c, the air flow in the air flow path 16 extending mainly along a circumferential locus is accelerated by the air flow (i) generated by the pressure change between the tapered section of the diaphragm 3 and the cover tapered section 13a. On the inner circumferential side of the recess 13c, the air flow in the air flow path 16 extending along a circumferential locus and the central air flow path 116 is accelerated by the air flow (ii) generated by the pressure change between the tapered section of the diaphragm 3 and the cover tapered section 13a.

[0046] Furthermore, the airflow in the airflow passage 16 along the arcuate path accelerates the flow rate of the airflow in the central airflow passage 116, and the relatively fast airflow in the central airflow passage 116 enhances the heat dissipation effect from the heat sink 33.

[0047] (Fourth embodiment) A speaker 301 of the fourth embodiment shown in Figures 7 and 8 has the same basic structure as the speaker 201 of the third embodiment shown in Figures 5 and 6. The cover member 13 provided in the speaker 301 of the fourth embodiment has a recess 13c along a circular arc locus formed on the outer periphery of the cover tapered portion 13a. The duct 14 is provided in the center including the central axis O of the cover member 13. A linear recess 13f is formed between the recess 13c and the duct 14.

[0048] In the space 15 between the vibrating part 2 and the cover member 13, in the region where the concave part 13c on the outer peripheral part is formed, the front-rear direction interval L1 between the vibrating part 2 and the cover member 13 becomes wider, and the space inside the concave part 13c or the space where the concave part 13c and the vibrating part 2 face each other forms an air flow path 16 along an arc locus. In the region where the linear concave part 13f is formed, the front-rear direction interval L4 between the diaphragm 3 and the cover member 13 becomes wider, and the space inside the linear concave part 13f or the space of the opposing part between the linear concave part 13f and the diaphragm 3 forms a linear air flow path 216. The linear air flow path 216 extends from the outer peripheral side toward the central part. Regarding the relationship between the intervals L1, L4 and the front-rear direction interval L2 in the region where the cover taper part 13a is provided, they become wider in the order of L2 < L1 < L4.

[0049] In the speaker 301 of the fourth embodiment, when the vibrating part 2 vibrates back and forth, in the space 15 between the vibrating part 2 and the cover member 13, the change in pressure becomes large at the part where the interval L2 where the cover taper part 13a and the raised part 13b are formed is short, and the speed of the air flow inside the air flow path 16 and the linear air flow path 216 with a wide front-rear direction interval becomes fast. Also, the air flow in the air flow path 16 along the arc locus accelerates the air flow in the linear air flow path 216, and air enters and exits between the space 15 and the external space through the internal space of the duct 14.

[0050] Since the circuit part 30 is installed outside the linear concave part 13f and the heat sink 33 is provided in the linear air flow path 216, the heat dissipation effect from the heat sink 33 is enhanced by the air flow in the linear air flow path 216.

[0051] The speaker shown in the first to fourth embodiments of the present invention can also use the Y2 direction as the sound generation direction. For example, the speaker is arranged in an exterior space of the vehicle such as an engine room or a trunk room and fixed to the vehicle body. At this time, the Y2 direction of the speaker faces the interior of the vehicle, and the duct 14 communicates with the interior space of the vehicle. When the diaphragm 3 of the speaker vibrates in the Y1-Y2 direction, the sound pressure generated on the Y2 side of the diaphragm 3 is given to the inside of the vehicle from the space 15 between the vibration part 2 and the cover member 13 through the internal space of the duct 14. Even in this usage method, the heat dissipation effect of the circuit part 30 can be enhanced by the air flow in the air flow path. [Explanation of symbols]

[0052] 1,101,201,301 Speaker 2 Vibration section 3 Vibration plate 4 Edge material 5 Bobbin 6 Cap member 7 Damper material 8 Voice coil 10 Support 13 Cover member 13a Cover tapered part 13c Recess 13d Central recess 13f Straight recess 14 Duct 15 Space 16 Air Flow Path 18 Openings 20 Magnetic circuit section 30 Circuit section 31 Circuit Board 32 Electronic elements 33 Heat sink 33a Groove 116 Central air passage 216 Straight air passage O center axis

Claims

1. A speaker including a vibration section including a diaphragm and a voice coil, a magnetic circuit section that applies a magnetic field to the voice coil, and a support body that supports the vibration section and the magnetic circuit section, The vibration portion is provided with a vibration plate having a tapered portion, the support includes a cover member that covers the vibration unit from one side in a vibration direction of the vibration unit, and a duct that connects a space between the vibration unit and the cover member to an external space outside the cover member, The cover member is provided with a cover tapered portion that faces the tapered portion and is inclined in the same direction as the tapered portion, and a recess that is recessed in a direction away from the vibration portion, in a part of an area covering the vibration portion, the recess being formed to be continuous with the cover tapered portion at a position farther away from the center of the vibration portion than the cover tapered portion and surrounding the center, a distance in the vibration direction between the vibration portion and the cover member in the recess is wider than the distance in the cover tapered portion, an air flow path is formed inside the recess, and the air flow path is connected to an inside of the duct, A speaker, comprising: a circuit section provided on the outside of said cover member; and a heat sink, at least a portion of which is exposed within said air flow path, said circuit section being connected to said heat sink.

2. 2. The speaker according to claim 1, wherein the air flow path is continuous and surrounds the center of the vibrating portion, and the duct is provided at a position offset from the center.

3. 2. The speaker according to claim 1, wherein the duct is provided at a position offset from the center of the vibration section, and a part of the air flow path extends to a position passing through the center.

4. 2. The speaker according to claim 1, wherein the duct is provided at the center of the vibration part, and a part of the air flow path extends from an outer periphery side of the vibration part to the center.

5. the heat sink has a groove; 5. The speaker according to claim 1, wherein the groove penetrates the air flow path in a direction toward the duct.

6. 6. A speaker as described in any one of claims 1 to 5, wherein the circuit section has a circuit board fixed to the outer surface of the cover member and a circuit element mounted on the circuit board, and the heat sink is connected to the circuit section through an opening formed in the cover member.

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