JP2015080121A - Electrodynamic speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrodynamic speaker which reduces its full height and is thin-shaped, includes a diaphragm formed from a first diaphragm at an inner diameter side and a second diaphragm at an outer diameter side, improves a low-pitched sound reproduction capability and is suitable to be mounted in a small-sized speaker cabinet.SOLUTION: An electrodynamic speaker 1 includes: a magnetic circuit 10 that specifies an annular magnetic void 14; a voice coil 4 including a cylindrical coil and a bobbin disposed in the magnetic void so as to be vibrated; a first diaphragm 2 of which the inner peripheral part is concatenated to the bobbin of the voice coil; a damper 5 and a second diaphragm 3 in which the inner peripheral part of the damper is concatenated to an outer peripheral part of the first diaphragm; a frame 6 concatenated to the damper outer peripheral part of the damper, the outer peripheral part of the second diaphragm and the magnetic circuit; and a dust cap 7 which covers the voice coil and the magnetic void of the magnetic circuit while concatenating its outer peripheral part to a main body part that is formed at an intermediate position between the inner peripheral part and the outer peripheral part of the first diaphragm.

Description

  A thin electrodynamic speaker with a low overall height, including a diaphragm composed of a first diaphragm on the inner diameter side and a second diaphragm on the outer diameter side. The present invention relates to an electrodynamic speaker suitable for mounting.

  In an audio device such as a display device or a gaming machine to which a speaker for reproducing sound is attached, it is desired to reduce the occupied space including the cabinet to which the speaker is attached. When the speaker to be attached is an electrodynamic speaker, the thickness dimension of the cabinet is governed by the overall height of the electrodynamic speaker. In particular, in an electrodynamic speaker that is thinned so as to reduce the overall height, which is the distance from the front end portion of the front frame to the magnetic circuit on the back side, the shape of the speaker diaphragm or the center support of the voice coil There may be a limit depending on the structure.

  Specifically, even if the damper that supports the voice coil at the center becomes closer to the magnetic circuit due to the reduction in thickness, it is necessary to take care not to generate abnormal noise by contacting the magnetic circuit. In the electrodynamic speaker, there is a problem that it becomes easy for the damper to collide with the magnetic circuit and generate abnormal noise at a frequency below the lowest resonance frequency f0 where the vibration system is greatly displaced. Therefore, conventionally, various electrodynamic speakers have been proposed in order to solve such problems.

  Conventionally, a frame, a damper whose outer peripheral edge is supported by the frame, a connecting member attached to the damper and movably supporting a voice coil bobbin, and a diaphragm fixed to the connecting member, A groove is formed in the vicinity of the upper end of the outer peripheral wall of the connecting member along the circumferential direction, and the inner peripheral edge of the diaphragm is fixed to the connecting member by an adhesive applied in the groove. There is a speaker characterized by The speaker is preferably characterized in that an inner peripheral edge portion of the diaphragm has a portion bent to the opposite side to the sound emission side, and the bent portion is inserted into the groove (patent) Reference 1).

  In addition, conventionally, a first diaphragm and a second diaphragm are disposed coaxially along the driving direction, and the outer peripheral portions of the first diaphragm and the second diaphragm are arranged on a frame. The first diaphragm and the second diaphragm are joined at a joint portion, and the inner periphery of the first or second diaphragm is a voice coil bobbin. There is a speaker characterized in that a dust cap is attached in the vicinity of the joint. Preferably, the joint portion is between an outer peripheral portion and an inner peripheral portion of the second diaphragm, and the inner peripheral portion of the second diaphragm is fixed to a voice coil bobbin. Preferably, the second diaphragm has a bent portion that protrudes toward the first diaphragm, and the joint is in the vicinity of the apex of the bent portion (Patent Document 2).

  Conventionally, a cylindrical portion 9b is integrally formed on the back surface 9a of the flat plate diaphragm 9 in which the central hole 9c is formed, and ribs 9d extending radially toward the outer peripheral portion of the back surface are integrally formed outside the cylindrical portion 9b. The magnetic circuit 2 is provided at the inner bottom of the frame 1 and at the center of the inner bottom of the frame 9b. The upper outer periphery of the voice coil 8 in which the voice coil winding 8a is located in the magnetic gap of the magnetic circuit 2 is formed. The flat plate-shaped center cap 11 is fitted to the front surface of the flat plate diaphragm 9 so that the inner peripheral portion of the flat plate diaphragm 9 is bonded to the portion and fitted into the tip of the voice coil 8 protruding from the center hole 9c. It is attached and has an inner diameter larger than that of the magnetic circuit 2, and a damper 12 disposed outside the cylindrical portion 9 b of the flat plate diaphragm 9 through the cylindrical portion 9 b so as not to mechanically interfere with the magnetic circuit 2. The cylindrical portion 9b is formed with a vent hole 9e for radiating the heat generated by the voice coil 8 disposed on the inside of the cylindrical portion 9b, and a heat radiating window forming a heat radiation path A together with the vent hole 9e. There is a speaker characterized in that 7 is formed on the frame 1 (Patent Document 3).

Japanese Patent Laying-Open No. 2005-269334 (FIGS. 1-2) JP 2006-222989 A (FIGS. 2 to 4) JP 2011-4308 A (FIGS. 1 to 6)

  However, in the electrodynamic loudspeakers of Patent Documents 1 to 3, a connection member or the like which is a special vibration member is used in order to prevent the damper and the magnetic circuit from interfering with each other and to facilitate the manufacturing process. Measures such as constituting a diaphragm from a plurality of members are required. However, as a result, there is a problem that the vibration system of the electrodynamic speaker becomes heavy and the reproduction level in the middle and high range tends to decrease. In addition, if the diaphragm is composed of multiple members in a thin shape with a low overall height, the electrodynamic loudspeaker can be made thin, but split vibration tends to occur, and the sound pressure frequency characteristics are disturbed, resulting in reproduced sound quality. There is a problem that decreases.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a thin electrodynamic speaker having a low overall height, the first diaphragm on the inner diameter side and the outer diameter side. It is an object of the present invention to provide an electrodynamic speaker that is suitable for mounting in a small speaker cabinet, having a diaphragm composed of the second diaphragm and having excellent sound reproduction capability in a low sound range.

  The electrodynamic speaker according to the present invention includes a magnetic circuit that defines an annular magnetic gap, a voice coil having a cylindrical coil and a bobbin that are arranged to be able to vibrate in the magnetic gap, and an inner peripheral portion of the bobbin of the voice coil. The first diaphragm to be connected, the damper and the second diaphragm connected to the outer periphery of the first diaphragm, and the damper outer periphery, the damper outer periphery, the second diaphragm outer periphery and the magnetic circuit, respectively. And a dust cap whose outer peripheral portion is connected to a main body portion formed at an intermediate position between the inner peripheral portion and the outer peripheral portion of the first diaphragm and covers the magnetic gap of the voice coil and the magnetic circuit.

  In the electrodynamic speaker of the present invention, the damper includes a damper inner peripheral portion connected to the outer peripheral portion of the first diaphragm, a damper outer peripheral portion connected to the frame, and between the damper inner peripheral portion and the damper outer peripheral portion. The inner diameter of the movable support is larger than the outer diameter of the magnetic circuit, and at least a part of the magnetic circuit is placed in the internal space defined by the movable support. Deploy.

  In the electrodynamic speaker of the present invention, the cross-sectional radius B that defines the outer peripheral portion of the dust cap is set to be approximately twice the cross-sectional radius A that defines the inner peripheral portion of the first diaphragm. The cross-sectional radius C that defines the outer peripheral portion of the second diaphragm is set to about three times the cross-sectional radius A, and the cross-sectional radius D that defines the outer peripheral portion of the second diaphragm is set to about four times the cross-sectional radius A.

  In the electrodynamic speaker according to the present invention, the first diaphragm further includes a plurality of radial ribs formed in the main body, and a lead wire connected to the coil of the voice coil is disposed in a groove defined by the rib. Has been.

  In the electrodynamic speaker of the present invention, the second diaphragm can vibrate the cone-shaped second diaphragm main body connected to the outer periphery of the first diaphragm, the outer periphery of the second diaphragm main body, and the frame. And an edge connected to.

  The operation of the present invention will be described below.

  The electrodynamic speaker according to the present invention includes a magnetic circuit that defines an annular magnetic gap, a voice coil having a cylindrical coil and a bobbin that are arranged to be able to vibrate in the magnetic gap, and an inner peripheral portion of the bobbin of the voice coil. The first diaphragm to be connected, the damper and the second diaphragm connected to the outer periphery of the first diaphragm, and the frame connected to the outer periphery of the damper and the outer periphery of the second diaphragm and the magnetic circuit, respectively. And a dust cap that covers the magnetic gap of the voice coil and the magnetic circuit. The dust cap is connected to a main body portion whose outer peripheral portion is formed at an intermediate position between the inner peripheral portion and the outer peripheral portion of the first diaphragm.

  Therefore, even if the diaphragm of the electrodynamic speaker is formed of the first diaphragm and the second diaphragm in a thin shape having a relatively low overall height, the dust cap appears on the convex portion of the main body of the first diaphragm. Since the mode of easy divided vibration is suppressed, it is possible to suppress the disturbance of the sound pressure frequency characteristics and improve the reproduction sound quality. In addition, since the weight of the vibration system of the electrodynamic speaker can be relatively reduced, there is an advantage that the reproduction level in the middle and high range is hardly lowered. The second diaphragm includes a cone-shaped second diaphragm main body connected to the outer periphery of the first diaphragm, and an edge connecting the outer periphery of the second diaphragm main body and the frame so as to vibrate. May be.

  Preferably, the damper includes a damper inner peripheral portion connected to the outer peripheral portion of the first diaphragm, a damper outer peripheral portion connected to the frame, and a movable support portion defined between the damper inner peripheral portion and the damper outer peripheral portion. The inner diameter dimension of the movable support portion is larger than the outer diameter dimension of the magnetic circuit, and at least a part of the magnetic circuit is disposed in the internal space defined by the movable support portion. Therefore, since the damper and the magnetic circuit do not interfere with each other, the damper does not collide with the magnetic circuit even at a frequency equal to or lower than the lowest resonance frequency f0 at which the vibration system is greatly displaced, and it is difficult to generate abnormal noise.

  In this electrodynamic speaker, preferably, the cross-sectional radius B that defines the outer peripheral portion of the dust cap is set to be approximately twice the cross-sectional radius A that defines the inner peripheral portion of the first diaphragm, so that the first vibration The cross-sectional radius C that defines the outer peripheral portion of the plate is set to about three times the cross-sectional radius A, and the cross-sectional radius D that defines the outer peripheral portion of the second diaphragm is set to about four times the cross-sectional radius A. That is, in the cross-sectional shape of the substantially circular speaker that is substantially axisymmetric, the cross-sectional radius B that defines the outer peripheral portion of the dust cap is set to the cross-sectional radius A with respect to the cross-sectional radius A that defines the inner peripheral portion of the first diaphragm. The cross-sectional radius C that defines the outer periphery of the first diaphragm is set to about three times the cross-sectional radius A, and the cross-sectional radius D that defines the outer periphery of the second diaphragm is Set to about 4 times. As a result, the dust cap is connected to the convex portion of the main body portion formed at an intermediate position between the inner peripheral portion and the outer peripheral portion of the main body of the first diaphragm. In addition to the suppression, the strength of the first diaphragm and the second diaphragm can be balanced, and the sound quality can be improved by suppressing the disturbance of the sound pressure frequency characteristics.

  The first diaphragm of the electrodynamic speaker may further include a plurality of ribs formed radially on the main body. A lead wire connected to the coil of the voice coil can be disposed in a groove defined by a rib formed on the main body of the first diaphragm. As a result, there is an advantage that the lead wire in the vibration mode in which the diaphragm of the electrodynamic speaker has a large amplitude can be prevented, and the occurrence of defects such as disconnection can be suppressed.

  A thin electrodynamic speaker with a low overall height, comprising a diaphragm composed of a first diaphragm on the inner diameter side and a second diaphragm on the outer diameter side, excellent in sound reproduction capability in the low range, and compact An electrodynamic speaker suitable for being attached to a speaker cabinet can be provided.

1 is a perspective view illustrating an electrodynamic speaker 1 according to a preferred embodiment of the present invention. Example 1 It is sectional drawing explaining the electrodynamic speaker 1 by preferable embodiment of this invention. Example 1 1 is a perspective view for explaining a configuration of an electrodynamic speaker 1 according to a preferred embodiment of the present invention (when a dust cap 7 is removed). Example 1 It is a graph explaining the sound pressure frequency characteristic of the electrodynamic speaker 1 by preferable embodiment of this invention, and the sound pressure frequency characteristic of the electrodynamic speaker of a comparative example. Example 1 / Comparative Example

  Hereinafter, although the electrodynamic speaker by preferable embodiment of this invention is demonstrated, this invention is not limited to these embodiment.

  1 to 3 are diagrams illustrating an electrodynamic speaker 1 according to a preferred embodiment of the present invention. FIG. 1 is a perspective view of the electrodynamic speaker 1, and FIG. 3 is a perspective view illustrating the configuration of the electrodynamic speaker 1 when the dust cap 7 is removed. FIG. 2 is a cross-sectional view of the electrodynamic speaker 1 taken along the line A-O-A ′. As will be described later, a part of the structure of the electrodynamic speaker 1, the internal structure, and the like are omitted. The direction in which the Z-axis extends is the height direction that defines the overall height or thickness.

  The electrodynamic speaker 1 of this embodiment is an electrodynamic speaker having a nominal aperture of about 10 cm. In the electrodynamic speaker 1, a circular speaker diaphragm that vibrates in the Z-axis direction includes a first diaphragm 2, a second diaphragm 3, and a dust cap 7. In the electrodynamic speaker 1, the magnetic circuit 10 is accommodated in the frame 6, and the total height H, which is the distance from the front end portion of the frame 6 on the front side to the magnetic circuit 10 on the back side, is about 33. .5mm and the electrodynamic speaker is relatively thin. Therefore, the electrodynamic speaker 1 is a speaker suitable for a device having a thin thickness that makes it relatively difficult to secure the thickness of a cabinet (not shown) to which the speaker is attached. An audio signal current is supplied to the side surface side of the frame 6.

  The first diaphragm 2, the second diaphragm 3, and the dust cap 7 constituting the speaker diaphragm are disposed coaxially along the Z-axis direction. The first diaphragm 2 on the inner circumferential side includes an inner circumferential portion 2 a connected to a bobbin 4 a of a voice coil 4 described later, a damper inner circumferential portion 5 a of a damper 5 described later, and an inner circumferential portion 3 a of the second diaphragm 3. The outer peripheral part 2b which connects, and the main-body part 2c formed in the intermediate position of the inner peripheral part 2a and the outer peripheral part 2b where a cross section is convex shape are included. The main body portion 2c of the first diaphragm 2 has six ribs 2d formed radially. Since the rib 2d constitutes a flat surface portion dropped from the main body portion 2c constituting the convex curved surface and a slope portion connecting the curved surface and the flat surface, the first diaphragm 2 is compared with the case where the rib 2d is not formed. Increased rigidity.

  On the other hand, the second diaphragm 3 on the outer peripheral side is constituted by a thin cone-shaped second diaphragm main body 3a having a low overall height and an edge 3b. The second diaphragm main body 3a is connected to the outer peripheral portion 2a of the first diaphragm 2 at the inner peripheral portion thereof, while the outer peripheral end of the edge 3b is supported by the edge 3b. It is fixed to the diaphragm fixing part 6a. The first diaphragm 2 of the electrodynamic loudspeaker 1 and the second diaphragm main body 3a of the second diaphragm 3 are made of a paper material formed by making paper fibers to reduce the weight of the speaker diaphragm. It is comprised including the base | substrate which carries out. On the other hand, the edge 3b only needs to be formed of a material that forms a free edge by a thin roll so as to freely support the second diaphragm 3 over the entire circumference. In the present embodiment, the edge 3b is foamed. Nitrile rubber (NBR). The edge 3b may be formed of an elastic body such as rubber formed by injecting flexible foam rubber into a mold and heating and foaming.

  The dust cap 7 includes a thin inverted dome-shaped dust cap body 7a having a low overall height and an outer peripheral portion 7b including a falling portion. The dust cap 7 covers a later-described voice coil 4 and a magnetic gap 14 of the magnetic circuit 10, and exhibits a function of preventing dust from entering the magnetic gap 14, and the first diaphragm 2, the second diaphragm 3, and the speaker. Configure the diaphragm. The outer peripheral part 7b of the dust cap 7 is connected to the main body part 2c of the first diaphragm 2 by an adhesive. As with the first diaphragm 2 and the second diaphragm 3, the dust cap 7 is configured to include a base body made of a paper material formed by making paper fibers.

  In the electrodynamic speaker 1, the bobbin 4 a constituting the voice coil 4 is connected to the inner peripheral portion 2 a of the first diaphragm 2. The voice coil 4 is formed of a bobbin 4a formed in a substantially cylindrical shape, and a substantially cylindrical coil 4b wound around one end thereof and supplied with a sound current. The other end side of the bobbin 4a around which the coil 4b is not wound is connected to the inner peripheral portion 2a of the first diaphragm 2 by an adhesive. The coil 4b is a substantially cylindrical coil formed by winding a round wire or a flat wire obliquely with respect to the Z-axis direction, which is the vibration direction, around the bobbin 4b. The bobbin 4a and the coil 4b of the voice coil 4 are disposed in a magnetic gap 14 of a magnetic circuit 10 described later so as to be vibrated by an edge 3b and a damper 5 described later.

  The damper 5 is a ring-shaped corrugation damper formed by impregnating a phenol resin with a woven fabric of flexible fibers as a base material. Specifically, the damper 5 includes a damper inner peripheral portion 5a including a rising portion connected to the outer peripheral portion 2c of the first diaphragm 2, and a damper outer peripheral portion including a falling portion connected to the damper fixing portion 6b of the frame 6. 5b and a movable support portion 5c defined between the damper inner peripheral portion 5a and the damper outer peripheral portion 5b. The movable support portion 5c has a corrugation that forms a flat damper, and the inner diameter radius rY of the movable support portion 5c is about 30.5 mm in this embodiment.

  The frame 6 is an iron plate frame that is press-molded into a basket shape corresponding to the diaphragm shape. The frame 6 includes a front-side moving plate fixing portion 6a, a damper fixing portion 6b formed at an intermediate portion, a magnetic circuit fixing portion 6c for fixing the magnetic circuit 10, and a connecting portion for connecting these fixing portions, A window defined between the plurality of connecting portions and a mounting portion for attaching the terminal 8 are provided. Therefore, the speaker vibration system including the first diaphragm 2, the second diaphragm 3, and the dust cap 7 is supported so as to be able to vibrate in the Z-axis direction with respect to the frame 6 and the magnetic circuit 10.

  The outer magnet type magnetic circuit 10 includes a center pole 11, a magnet 12, and a plate 13. The magnetic circuit 10 has a magnetic gap 14 that generates a DC magnetic field between the central convex portion of the center pole 11 and the inner peripheral end of the plate 13. Each member constituting the magnetic circuit 10 is fixed with an adhesive. The magnetic circuit 10 is also fixed to the magnetic circuit fixing portion 6c of the frame 6 with an adhesive. Since the entire magnetic circuit 10 is accommodated inside the frame 6, the electrodynamic speaker 1 can be made thin. The maximum radial dimension of the magnetic circuit 10 is defined by the outer radius rx of the magnet 12 and is about 30.0 mm in this embodiment.

  That is, the inner diameter radius dimension rY of the movable support portion 5 c of the damper 5 is configured to be larger than the outer diameter radius dimension rX of the magnetic circuit 10. Therefore, the electrodynamic speaker 1 is configured so that at least a part of the magnetic circuit 10 is disposed in the internal space defined by the movable support portion 5c of the damper 5, as shown in FIG. In the electrodynamic speaker 1, since the damper 5 and the magnetic circuit 10 do not interfere with each other, the damper 5 does not collide with the magnetic circuit 10 even at a frequency lower than the lowest resonance frequency f0 at which the vibration system is greatly displaced, and noise is generated. It becomes difficult to do.

  Lead wires 4c corresponding to both ends of the coil 4b of the voice coil 4 are partially exposed on the front side of the speaker diaphragm as shown in FIG. The lead wire 4c is pulled out to a connecting portion between the bobbin 4a and the inner peripheral portion 2a of the first diaphragm 2, and as shown in FIG. 3, ribs formed on the main body 2c of the first diaphragm 2 are formed. One end of the tinsel wire 9 that passes through the eyelet provided on the second diaphragm 3 after being fixed by an adhesive along the line 2d and beyond the connecting portion between the first diaphragm 2 and the second diaphragm 3 Each side is soldered and electrically connected. The other ends of the two tinsel wires 9 are led to the corresponding positive and negative input terminals of the terminal 8, respectively, so that when the second diaphragm 3 vibrates, it does not come into contact with other parts and generate noise. After being molded into a predetermined shape, it is soldered and electrically connected.

  In the electrodynamic speaker 1, when an audio current is supplied to the coil 4 a of the voice coil 4, a driving force is applied to the coil 4 a disposed in the magnetic gap 14, and the voice coil 4 vibrates in the Z-axis direction and is connected. The first diaphragm 2, the second diaphragm 3, the dust cap 7 and the damper 5 that have been made also vibrate in the Z-axis direction and reproduce sound. It is preferable that the first diaphragm 2, the second diaphragm 3, and the dust cap 7 constituting the speaker diaphragm perform piston vibration without dividing vibration in a wide frequency band. In a thin electrodynamic speaker 1 having a low overall height including a speaker diaphragm composed of a first diaphragm 2 on the inner diameter side and a second diaphragm 3 on the outer diameter side, a frequency near or below the lowest resonance frequency f0. However, since divided vibration is likely to occur, it is preferable to suppress the generation of divided vibration in order to increase the sound reproduction capability in the low frequency range.

  Therefore, in the electrodynamic speaker 1 of the present embodiment, as shown in FIG. 2, the cross-sectional radius B (about 20 mm) that defines the outer peripheral portion 7 b of the dust cap 7 is the inner peripheral portion 2 a of the first diaphragm 2. Is set to about twice the cross-sectional radius A (about 10 mm). The cross-sectional radius C (about 30 mm) that defines the outer periphery of the first diaphragm is set to be about three times the cross-sectional radius A, and the cross-sectional radius D (about 40 mm) that defines the outer periphery of the second diaphragm is set. , About 4 times the cross-sectional radius A.

  That is, the electrodynamic loudspeaker 1 is configured so that the outer peripheral portion 7b of the dust cap 7 is based on the cross-sectional radius A that defines the inner peripheral portion 2a of the first diaphragm 2 in the cross-sectional shape of the substantially circular speaker that is substantially axisymmetric. Is set to about twice the section radius A, the section radius C defining the outer peripheral portion 2b of the first diaphragm 2 is set to about three times the section radius A, and the second diaphragm 3 The cross-sectional radius D that defines the outer periphery of the main body 3a is set to about four times the cross-sectional radius A.

  In addition, the description of about 2 times, about 3 times, and about 4 times in the above means that the dimensions 2A, 3A, which are an integral multiple, when the reference cross-sectional radius A is specified in the unit of millimeters (mm) by one decimal point. 4A may be included so long as it includes a range of values corresponding to the case where 4A is rounded down or rounded up to zero decimal place. For example, the cross-sectional radius B set to about twice the cross-sectional radius A (about 10 mm) is a range corresponding to a range of ± 10% of the doubled dimension 2A (= 20 mm) (about 19.8 mm to about 20. 2 mm).

  FIG. 4 is a graph for explaining the sound pressure frequency characteristics of the electrodynamic speaker 1 and the sound pressure frequency characteristics of the electrodynamic speaker of the comparative example. Specifically, FIG. 4A shows an on-axis 1 m sound pressure frequency characteristic [/ 1 W] (˜2 kHz) of the electrodynamic speaker 1, and FIG. 4B shows an electrodynamic speaker. 1 is an axial 1 m sound pressure frequency characteristic [/ 1 W] (˜2 kHz) of the electrodynamic speaker 100 of a comparative example in which the configuration of the dust cap is different from that of FIG. Unlike the dust cap 7 described above, the electrodynamic speaker 100 of the comparative example includes a dust cap that covers the front side end of the bobbin 4 a of the voice coil 4.

  As shown in the graph of FIG. 4A, in the electrodynamic speaker 1 of the present embodiment, the dust cap 7 is formed at an intermediate position between the inner peripheral portion 2 a and the outer peripheral portion 2 b of the main body of the first diaphragm 2. Since it is connected to the main body portion 2c, the mode of split vibration that tends to appear in the main body portion 2c is suppressed, the strength of the first diaphragm 2 and the second diaphragm 3 is balanced, and the sound pressure frequency characteristics. The playback sound quality can be improved by suppressing the disturbance.

  On the other hand, as shown in the graph of FIG. 4 (b), the electrodynamic speaker 100 of the comparative example suppresses divided vibration generated in the vicinity of about 400 Hz in the speaker diaphragm as compared with the electrodynamic speaker 1. The sound pressure frequency characteristic has large peaks and dips. This is because the structure of the dust cap is different, and as a result, the cross-sectional radius B that defines the outer peripheral portion of the dust cap is set to about twice the cross-sectional radius A that defines the inner peripheral portion 2a of the first diaphragm 2. This is because the strength of the first diaphragm 2 and the second diaphragm 3 cannot be balanced, and the first diaphragm 2 vibrates in a divided manner.

  Regarding the second-order and third-order harmonic distortion characteristics, the electrodynamic speaker 1 of this embodiment is superior to the electrodynamic speaker 100 of the comparative example. In the electrodynamic speaker 1 of the present embodiment, the lead wire 4c of the voice coil 4 is disposed along the rib 2d of the first diaphragm 2 with increased rigidity, and is thus fixed to the first diaphragm 2. It is possible to reduce the occurrence of defects such as disconnection at the portion.

  In the above-described embodiment, the thin-type electrodynamic speaker 1 includes the first diaphragm 2 and the second diaphragm 3 that vibrate in the Z-axis direction, and the first diaphragm 2 forms a convex curved surface. 2c, and the dust cap 7 is connected to the main body 2c. However, the main body 2c of the first diaphragm 2 is not limited to a convex curved surface as in the present embodiment. The main body 2c of the first diaphragm 2 may have a cone shape like the second diaphragm 3, or may have a planar shape constituting a planar diaphragm.

  The electrodynamic speaker of the present invention can be applied not only as a speaker built in video / audio equipment such as a display but also to a game machine having a cabinet with a built-in speaker for reproducing sound, a game machine such as a slot machine, etc. It is. In addition, the electrodynamic speaker provided with the speaker magnetic circuit of the present invention has a low overall height and can realize a speaker system that reproduces sound in a small and thin cabinet, so that it is particularly suitable for a vehicle speaker having a limited installation space. Suitable.

1 electrodynamic speaker 2 first diaphragm,
3 Second diaphragm 4 Voice coil 5 Damper 6 Frame 7 Dust cap 8 Terminal 9 Kinshi wire 10 Magnetic circuit 11 Pole plate 12 Magnet 13 Plate 14 Magnetic gap

Claims (5)

A magnetic circuit that defines an annular magnetic gap, a voice coil having a cylindrical coil and a bobbin that are arranged to vibrate in the magnetic gap, and a first diaphragm having an inner peripheral portion connected to the bobbin of the voice coil A damper connected to the outer periphery of the first diaphragm and an inner periphery of the damper and the second diaphragm; a damper outer periphery of the damper; an outer periphery of the second diaphragm; and a frame connected to the magnetic circuit. A dust cap whose outer peripheral portion is connected to the inner peripheral portion of the first diaphragm and a main body portion formed at an intermediate position of the outer peripheral portion and covers the magnetic gap of the voice coil and the magnetic circuit; Comprising
Electrodynamic type speaker. The damper is defined between the damper inner periphery connected to the outer periphery of the first diaphragm, the damper outer periphery connected to the frame, the damper inner periphery, and the damper outer periphery. A movable support portion having an inner diameter dimension larger than an outer diameter dimension of the magnetic circuit, and at least a part of the magnetic circuit in an internal space defined by the movable support portion. To place,
The electrodynamic speaker according to claim 1. A cross-sectional radius B that defines the outer peripheral portion of the dust cap is set to approximately twice a cross-sectional radius A that defines the inner peripheral portion of the first diaphragm, and the outer peripheral portion of the first diaphragm is defined. The cross-sectional radius C is set to about three times the cross-sectional radius A, and the cross-sectional radius D defining the outer peripheral portion of the second diaphragm is set to about four times the cross-sectional radius A.
The electrodynamic speaker according to claim 1 or 2. The first diaphragm further includes a plurality of ribs formed radially on the main body, and a lead wire connected to the coil of the voice coil is disposed in a groove defined by the rib.
The electrodynamic speaker according to any one of claims 1 to 3. The second diaphragm is connected to the outer periphery of the first diaphragm, a cone-shaped second diaphragm main body, an outer periphery of the second diaphragm main body and an edge that connects the frame to be vibrated; including,
The electrodynamic speaker according to claim 1.