Patent Description:
<CIT> describes a speaker having a bottom chamber and a frame. The bottom chamber holds a magnetic circuit, and the frame supports a diaphragm and a damper. The magnetic circuit is formed of a magnet disposed as an inner portion of the magnetic circuit and a yoke disposed as an outer portion thereof. Front and rear magnetic gaps are formed between the outer peripheral surface of the magnet and the inner peripheral surface of the yoke. A coil bobbin is fixed to the diaphragm, and two voice coils are wound around the coil bobbin. The voice coils are positioned inside the respective front and rear magnetic gaps.

The frame has a bottom portion that is fixed to the front end surface of the bottom chamber using mounting screws. The inner diameter of the bottom portion of the frame is set to be slightly smaller than the outer diameter of the yoke that is held by the bottom chamber. The inner periphery of the bottom portion presses the front end surface of the yoke from in front. The magnet of the magnetic circuit is fixed to the bottom chamber due to the magnetic attraction, whereas the yoke of the magnetic circuit is restricted from moving in the thrust direction in the bottom chamber due to the front end surface of the yoke being pressed by the inner periphery of the bottom portion of the frame.

According to the speaker described in <CIT>, it is difficult to align the front end surface of the yoke with the front end surface of the bottom chamber to which the bottom portion of the frame is fixed because of deviation within the dimensional tolerances of the bottom chamber and the frame. Accordingly, a step (a difference in level) is inevitably produced between the front end surface of the bottom chamber and the front end surface of the yoke.

If the front end surface of the bottom chamber is positioned rearward from the front end surface of the yoke, a gap occurs between the bottom portion of the frame and the front end surface of the bottom chamber because the inner periphery of the bottom portion of the frame is in contact with the front end surface of the yoke. As a result, the frame and the bottom chamber cannot be connected stably by the mounting screws. The tightening force of the mounting screws tends to deform the frame or may even break the frame. The deformation of the frame may deteriorate the vibration characteristics of the diaphragm that is supported by the frame. If the front end surface of the yoke is positioned rearward from the front end surface of the bottom chamber, the magnetic circuit cannot be stably restricted from moving in the thrust direction, and the magnetic circuit may be displaced due to external vibrations.

<CIT> discloses speaker device comprising a voice coil that is arranged in a magnetic gap formed in a magnetic circuit unit, a diaphragm that vibrates with a voice coil, and a damper that is provided between a diaphragm and a frame and supports the diaphragm relative to the frame so that the diaphragm can vibrate. A damper holder is fixed to the frame and supports the damper, and the magnetic circuit unit is arranged between the damper holder and the frame.

According to <CIT>, a speaker device includes a magnetic circuit with a magnetic gap; a voice coil disposed in the magnetic gap, and a diaphragm. The speaker device vibrates the voice coil and the diaphragm by energizing an electric current through the voice coil. The speaker device includes a fastening structure for fastening a yoke, a magnet, and a plate constituting the magnetic circuit.

The present invention is directed to a speaker defined according to claim <NUM>. Further aspects of the invention are defined according to the dependent claims.

Accordingly, it is an object of the present invention to provide a speaker having a structure that enables the frame to stably hold the magnetic circuit and that does not readily cause a large stress to act on the frame even if a step is produced between the mounting surface of the frame and the front end surface of the magnetic circuit.

According to an aspect of the present invention, a speaker includes a frame, a diaphragm that the frame supports so as to enable the diaphragm to vibrate, a coil that drives the diaphragm to vibrate, and a magnetic circuit that is positioned rearward relative to the diaphragm and applies a magnetic field to the coil. The frame has a magnetic circuit holder in which the magnetic circuit is held, and the magnetic circuit has a restriction surface that faces frontward. The magnetic circuit holder has pressing arms that protrude from a ring-like body towards a center of the ring-like body, that are elastically deformable and that are disposed so as to be in contact with the restriction surface. Contact portions between respective pressing arms and the restriction surface are disposed with spacing therebetween. Each pressing arm has a substantially triangular shape of which the width gradually becomes smaller towards a tip portion of the pressing arm protruding towards the center of the ring-like body.

In the speaker, the magnetic circuit holder may be configured such that the magnetic circuit is inserted rearward thereinto and is fixed therein.

In the speaker, the magnetic circuit holder may have a mounting surface that faces frontward, and a pressing portion may have a screw-fixation portion that is screw-fixed to the mounting surface. The pressing arms may be integrally formed with the pressing portion. The pressing arms and the screw-fixation portion may be disposed such that a radial line that extends from a center of the magnetic circuit and on which the screw-fixation portion of the pressing portion is positioned does not overlap radial lines that extend from the center of the magnetic circuit and on which respective pressing arms are positioned.

In the speaker, the pressing portion may be formed separately from the frame.

In the speaker, the pressing portion may be formed integrally with the frame.

In the speaker, a damper support member to which an outer peripheral portion of a damper that supports the diaphragm is fixed may be formed separately from the frame, and the pressing portion may be interposed between the mounting surface and the damper support member.

In the speaker, a damper support member to which an outer peripheral portion of a damper that supports the diaphragm is fixed may be formed separately from the frame, and the pressing portion may be formed integrally with the damper support member.

In the speaker, the frame may have a diaphragm support member that supports the diaphragm and a magnetic circuit holder member that holds the magnetic circuit, and the pressing portion may be formed integrally with the diaphragm support member.

In the speaker, the frame may have a diaphragm support member that supports the diaphragm and a magnetic circuit holder member that holds the magnetic circuit, and the pressing portion may be interposed between the mounting surface and the diaphragm support member.

The speaker according to the present invention is particularly configured such that the pressing arms press the restriction surface of the magnetic circuit while the magnetic circuit is held by the magnetic circuit holder positioned rearward relative to the frame. This enables the frame to stably hold the magnetic circuit. In addition, the contact portions between respective pressing arms and the restriction surface are disposed with spacing therebetween. This can prevent a large stress from acting on the frame when the pressing arms deform even if a step is produced between the restriction surface of the magnetic circuit and the mounting surface of the magnetic circuit holder.

According to an embodiment, a diaphragm of the speaker is shaped having a recessed side and a copped side, e.g. like a cone. Generally, according to an embodiment, the frontward direction is a direction extending from a recessed side (e.g. the recessed side of the cone) of the diaphragm and the rearward direction is opposite to the frontward direction.

In a speaker <NUM> according to a first embodiment (and other embodiments) of the present invention, the front-rear direction thereof is aligned with the Z1-Z2 direction as illustrated in <FIG>, whereby the Z1 direction is the frontward direction and the Z2 direction is the rearward direction. The speaker <NUM> may produce sound in the frontward, particularly the Z1 direction or may produce sound in the rearward, particularly Z2 direction. <FIG> illustrates a center axis O that extends in the front-rear direction (in the Z1-Z2 direction). A major part of the speaker <NUM> is structured substantially in rotation symmetry with respect to the center axis O. As illustrated in <FIG>, the X-axis and the Y-axis orthogonally intersect each other on a plane that orthogonally intersects the center axis O. Accordingly, the X-Y plane orthogonally intersects the center axis O.

As illustrated in <FIG> and <FIG>, a frame <NUM> and a damper support member <NUM> constitute the support structure of the speaker <NUM>. The frame <NUM> and the damper support member <NUM> are made of a magnetic metal or a non-magnetic metal or alternatively made of a synthetic resin. As illustrated in <FIG>, the frame <NUM> is integrally formed of a magnetic circuit holder <NUM>, a diaphragm support <NUM>, and connection ribs <NUM>. The magnetic circuit holder <NUM> is positioned in a rear side (a side in the Z2 direction) of the frame <NUM>, and the diaphragm support <NUM> is positioned in a front side (a side in the Z1 direction) thereof. The connection ribs <NUM> connect the magnetic circuit holder <NUM> and the diaphragm support <NUM> to each other. The speaker <NUM> of the embodiment is of an in-car use type, and as illustrated in <FIG>, the outside surface of the magnetic circuit holder <NUM> of the frame <NUM> is covered with an outer casing (exterior casing) <NUM>.

The magnetic circuit holder <NUM> of the frame <NUM> has a holder recess 11a that is recessed rearward (in the Z2 direction). A magnetic circuit <NUM> is inserted rearward into the holder recess 11a and is held in this state. As illustrated in <FIG>, the magnetic circuit <NUM> has an outer structure that is positioned outside a bobbin <NUM> and an inner structure that is positioned inside the bobbin <NUM>. The outer structure is formed by layering a ring-like magnet <NUM>, a ring-like outer front yoke 32a, and a ring-like outer rear yoke 33a. The outer front yoke 32a is joined to the front side of the magnet <NUM>, and the outer rear yoke 33a is joined to the rear side of the magnet <NUM>. The inner structure of the magnetic circuit <NUM> is formed by layering an inner front yoke 32b positioned in the front and an inner rear yoke 33b positioned in the rear. The yokes 32a, 32b, 33a, and 33b are made of a magnetic metal.

In the magnetic circuit <NUM>, a front magnetic gap G1 is formed between the inner peripheral surface of the outer front yoke 32a and the outer peripheral surface of the inner front yoke 32b. The inner peripheral surface and the outer peripheral surface oppose each other. Similarly, a rear magnetic gap G2 is formed between the inner peripheral surface of the outer rear yoke 33a and the outer peripheral surface of the inner rear yoke 33b.

As illustrated in <FIG>, the speaker <NUM> has a phase plug <NUM> disposed in a central region thereof. The phase plug <NUM> is made of a light metal or a synthetic resin, and the outer surface of the phase plug <NUM> is tapered such that the diameter of the phase plug <NUM> gradually decreases as it goes frontward (in the Z1 direction). The phase plug <NUM> has a flat rear end surface 4a that faces rearward (in the Z2 direction). A threaded hole 4b is bored frontward at the center of the rear end surface 4a. A front end surface 32c of the inner front yoke 32b of the magnetic circuit <NUM> is also a flat surface. The rear end surface 4a of the phase plug <NUM> lies on the front end surface 32c of the inner front yoke 32b.

A fixation hole is formed in a rear end portion <NUM> of the frame <NUM>. The inner rear yoke 33b and the inner front yoke 32b, which form the inner structure of the magnetic circuit <NUM>, are inserted rearward into the holder recess 11a of the magnetic circuit holder <NUM>. The shaft of a fixation screw <NUM>, which is inserted into the fixation hole of the rear end portion <NUM> from behind, is further inserted through the center holes of the inner rear yoke 33b and the inner front yoke 32b. Subsequently, a male thread portion formed at the end of the shaft of the fixation screw <NUM> is screwed into the threaded hole 4b formed in the phase plug <NUM>. The inner rear yoke 33b, the inner front yoke 32b, and the phase plug <NUM> are positioned appropriately and fixed firmly together due to the screw engagement between the phase plug <NUM> and the fixation screw <NUM> inserted along the center axis O.

The magnet <NUM>, the outer front yoke 32a, and the outer rear yoke 33a are positioned with center-to-center alignment in the outer structure of the magnetic circuit <NUM>. The magnet <NUM> magnetically attracts the outer front yoke 32a and the outer rear yoke 33a so as to fix them together. The magnet <NUM>, the outer front yoke 32a, and the outer rear yoke 33a are further adhered to each other using an adhesive. The outer structure is inserted rearward into the holder recess 11a of the magnetic circuit holder <NUM>. Subsequently, a rear end surface 33c of the outer rear yoke 33a, in other words, the rear end surface of the outer structure, is adhered, using an adhesive, to the front surface of the rear end portion <NUM> of the frame <NUM>. In the process of mounting the magnetic circuit <NUM>, the magnetic circuit <NUM> is fixed, using a tool, such that both centers of the inner structure and the outer structure of the magnetic circuit <NUM> are aligned with the center axis O.

As illustrated in <FIG>, the ring-like body <NUM> of the damper support member <NUM> has a damper fixation surface <NUM> formed at the inner peripheral surface thereof. The damper fixation surface <NUM> is recessed rearward (in the Z2 direction). The damper fixation surface <NUM> is a flat surface positioned parallel to the X-Y plane. The ring-like body <NUM> has fixation legs <NUM>, which are integrally formed with the ring-like body <NUM> so as to protrude rearward (in the Z2 direction) from the ring-like body <NUM>. Five fixation legs <NUM> are arranged circumferentially with equiangular spacing. Fixation holes 23a are formed at respective fixation legs <NUM>.

As illustrated in <FIG>, a mounting surface <NUM> is formed in the magnetic circuit holder <NUM> of the frame <NUM> so as to surround the opening of the holder recess 11a. The mounting surface <NUM>, which extends parallel to the X-Y plane, is formed in a ring-like region in the magnetic circuit holder <NUM> with the center axis O being at the center. Threaded holes <NUM> are formed at the mounting surface <NUM>. Five threaded holes <NUM> are arranged equiangularly with the center axis O being at the center.

The speaker <NUM> illustrated in <FIG> has a pressing portion <NUM>. The pressing portion <NUM> is a pressing member formed separately from the frame <NUM> and from the damper support member <NUM>. The pressing portion (pressing member) <NUM> is formed of an elastically deformable board, such as a metal board or a synthetic resin board. As illustrated in <FIG>, the pressing portion <NUM> is fixed between the mounting surface <NUM>, which is the front end surface of the magnetic circuit holder <NUM>, and rear surfaces 23b of respective fixation legs <NUM> of the damper support member <NUM>.

As illustrated in <FIG>, the pressing portion <NUM> has a ring-like body <NUM>, pressing arms <NUM>, and fixation holes <NUM> formed in the ring-like body <NUM>. Five fixation holes <NUM> are formed equiangularly with the center axis O being at the center. Five pressing arms <NUM> are also formed equiangularly with the center axis O being at the center. The ring-like body <NUM> has such a diameter as to fit on the mounting surface <NUM> of the magnetic circuit holder <NUM>. Fixation holes <NUM> are formed at positions corresponding to respective threaded holes <NUM> formed at the mounting surface <NUM>.

Each pressing arm <NUM> is formed so as to protrude toward the center axis O from the ring-like body <NUM>. The pressing arm <NUM> has a substantially triangular shape of which the width gradually becomes smaller toward a tip portion 42a of the pressing arm <NUM>. Openings <NUM> are formed in the pressing portion <NUM>. Each opening <NUM> is recessed into the pressing arm <NUM> from the outer periphery of the pressing portion <NUM>. Provision of the opening <NUM> can reduces the effective width of each pressing arm <NUM>. Note that the tapered (substantially triangular) pressing arm <NUM> may have a hole at the center and the hole may serve as the opening <NUM>. The pressing arm <NUM>, which has the shape tapered toward the tip portion 42a and has the opening <NUM> formed therein, is adjusted so as to exhibit a relatively small elastic modulus for bending deformation in the thickness direction.

As illustrated in <FIG> and <FIG>, in the state of the pressing portion <NUM> being placed between the mounting surface <NUM> of the magnetic circuit holder <NUM> and the rear surfaces 23b of the fixation legs <NUM>, five fixation screws <NUM> are inserted rearward through respective fixation holes 23a formed in the fixation legs <NUM> and through respective fixation holes <NUM> formed in the pressing portion <NUM> and subsequently screwed into respective threaded holes <NUM> formed at the mounting surface <NUM>. The tightening force of the fixation screws <NUM> can fix the ring-like body <NUM> firmly to the mounting surface <NUM>. The fixation holes 23a, the fixation holes <NUM>, the fixation screws <NUM>, and the threaded holes <NUM> constitute screw-fixation portions that fix the pressing portion <NUM> to the magnetic circuit holder <NUM>.

As illustrated in <FIG> and <FIG>, the outer front yoke 32a of the magnetic circuit <NUM> has a ring-like restriction surface 32d formed so as to face frontward. The restriction surface 32d is the surface that restricts displacement of the outer structure of the magnetic circuit <NUM>. The restriction surface 32d is positioned parallel to the X-Y plane that orthogonally intersects the center axis O. The pressing arms <NUM>, which protrude toward the center axis O from the pressing portion <NUM> that is fixed to the mounting surface <NUM>, are in contact with the restriction surface 32d of the magnetic circuit <NUM>.

As illustrated in the section of <FIG>, the restriction surface 32d is positioned slightly frontward (in the Z1 direction) relative to the mounting surface <NUM>. Accordingly, a step is produced between the restriction surface 32d and the mounting surface <NUM>. When the pressing arms <NUM> are brought into contact with the restriction surface 32d, the pressing arms <NUM> are bent frontward (in the Z1 direction). The pressing arms <NUM> thereby provide elastic forces that elastically press the outer structure of the magnetic circuit <NUM> rearward (in the Z2 direction). On the other hand, the restriction surface 32d and the mounting surface <NUM> may be at the same position in the front-rear direction, or the restriction surface 32d may be positioned rearward relative to the mounting surface <NUM>. In such cases, the pressing arms <NUM> may be bent rearward in advance when in the free state so that the pressing arms <NUM> can elastically press the restriction surface 32d rearward.

As illustrated in <FIG>, the ring-like body <NUM> of the pressing portion <NUM> is positioned radially away from the restriction surface 32d in the region where the pressing arms <NUM> are not present. The contact portions between the pressing arms <NUM> and the restriction surface 32d are positioned so as to have a space therebetween in the circumferential direction with the center axis O being at the center. In other words, the pressing portion <NUM> does not elastically press the entire circumferential portion of the restriction surface 32d but elastically press only parts thereof using the pressing arms <NUM>. Multiple pressing arms <NUM> distribute the stress generated by the elastic pressure over the entire pressing portion <NUM>, which prevents an excessive stress from acting on the entire pressing portion <NUM>.

Each screw-fixation portion having the fixation hole <NUM> is positioned on a radial line R1 that extends from the center axis O, whereas each pressing arm <NUM> is positioned on a radial line R2 that extends from the center axis O. In other words, the screw-fixation portion and the pressing arm <NUM> are not positioned on the same radial line. As a result, the stress caused by elastic deformation of each pressing arm <NUM> does not readily act on the screw-fixation portion, which can reduce the likelihood that a large stress generated by elastic deformation of the pressing arms <NUM> acts on the frame <NUM>. The radial line R2 divides the angular distance between circumferentially adjacent fixation holes <NUM> into halves, and the widthwise center of each pressing arm <NUM> is positioned on the radial line R2. Moreover, the pressing arms <NUM> and the screw-fixation portions are positioned equidistantly in the circumferential direction. Accordingly, the stress caused by the elastic deformation of the pressing arms <NUM> does not act concentratedly on a particular screw-fixation portion, which reduces the likelihood that the stress caused by deformation of the pressing arms <NUM> acts on the frame <NUM>.

Moreover, in the speaker <NUM> of the first embodiment, the pressing portion <NUM> and the damper support member <NUM> to which the pressing portion <NUM> is fixed are formed separately from the frame <NUM>, which reduces the likelihood that the stress caused by the elastic deformation of the pressing arms <NUM> directly acts on the frame <NUM>.

As illustrated in <FIG>, the speaker <NUM> has a diaphragm <NUM> disposed in a central region thereof. The diaphragm <NUM> is shaped like a cone. An elastically deformable edge member <NUM> is joined to a circumferential portion of the diaphragm <NUM> that faces frontward. The circumferential edge of the edge member <NUM> is further joined to a front end portion of the frame <NUM>. A bobbin <NUM> is joined to a central portion of the diaphragm <NUM>. Voice coils <NUM> are formed at two positions on a rear side of the bobbin <NUM>. The voice coils <NUM> are formed by winding conducting wires around the cylindrically shaped bobbin <NUM>. One of the voice coils <NUM> is disposed inside the front magnetic gap G1 of the magnetic circuit <NUM>, and the other voice coil <NUM> is disposed in the rear magnetic gap G2. An inner peripheral portion of a damper <NUM> is joined to the outer peripheral surface of the bobbin <NUM>. The damper <NUM> has a corrugate-shaped section. The outer peripheral portion of the damper <NUM> is joined to the damper fixation surface <NUM> of the damper support member <NUM>.

In the speaker <NUM> illustrated in <FIG>, a driving current is applied to the two voice coils <NUM> in accordance with an audio signal output from an audio amplifier. A vibrating portion that includes the diaphragm <NUM> and the voice coils <NUM> vibrates in the front-rear direction due to the electromagnetic force generated by the driving current and the magnetic fluxes that traverse the voice coils <NUM> in the front magnetic gap G1 and the rear magnetic gap G2 of the magnetic circuit <NUM>. The vibrating portion thereby generates sound pressures in accordance with the frequency of the driving current and produces sound frontward (in the Z1 direction) or rearward (in the Z2 direction).

As illustrated in <FIG>, the inner structure of the magnetic circuit <NUM>, which includes the inner front yoke 32b and the inner rear yoke 33b, is firmly fixed inside the magnetic circuit holder <NUM> of the frame <NUM> by the fixation screw <NUM> screwed into the phase plug <NUM>. On the other hand, the outer structure in which the magnet <NUM>, the outer front yoke 32a, and the outer rear yoke 33a are layered is adhered together inside the magnetic circuit holder <NUM>. The outer structure may be displaced due to, for example, external vibrations. The speaker <NUM> of the embodiment, however, is configured such that the outer structure is elastically pressed rearward by the pressing arms <NUM> of the pressing portion <NUM> disposed at the magnetic circuit holder <NUM> as illustrated in <FIG>, which can reduce the likelihood of the outer structure moving unexpectedly.

As illustrated in <FIG>, the contact portions between respective pressing arms <NUM> and the restriction surface 32d of the outer structure are arranged in the circumferential direction with spacing therebetween, which enables substantially only the pressing arms <NUM> to be deformed elastically and thereby prevents a large stress from acting on the frame <NUM>. This reduces the likelihood of the frame <NUM> being bent or broken. Accordingly, this reduces the likelihood of the vibration characteristics of the diaphragm <NUM> deteriorating due to deformation of the frame <NUM>.

<FIG> illustrate a speaker <NUM> according to a second embodiment of the present invention. The speaker <NUM> includes the frame <NUM> and a damper support member <NUM>. The damper support member <NUM> is made by integrally forming the damper support member <NUM> and the pressing portion <NUM> that are used for the speaker <NUM> of the first embodiment. The entire damper support member <NUM> is made integrally by injection molding using a synthetic resin or by die-casting using a metal. Alternatively, the damper support member <NUM> and the pressing portion <NUM> may be formed separately in advance and joined together using an adhesive or the like to form the damper support member <NUM>.

As illustrated in <FIG> and <FIG>, the fixation legs <NUM> are integrated with the ring-like body <NUM> of the pressing portion <NUM> in the damper support member <NUM>, and fixation holes 123a are formed through respective fixation legs <NUM> and through the ring-like body <NUM>. As illustrated in <FIG>, the damper support member <NUM> is fixed to the mounting surface <NUM> of the magnetic circuit holder <NUM> using the fixation screws <NUM>, which are inserted into the fixation holes 123a and screwed into the threaded holes <NUM>. The fixation screws <NUM>, the fixation holes 123a, and the threaded holes <NUM> constitute the screw-fixation portions. At least the pressing arms <NUM> in the pressing portion <NUM> are formed so as to be elastically deformable. As illustrated in <FIG>, the pressing arms <NUM> elastically press the restriction surface 32d, which is the front end surface of the magnetic circuit <NUM>, so as to prevent the outer structure of the magnetic circuit <NUM> from moving easily.

<FIG> illustrates a speaker <NUM> according to a third embodiment of the present invention. The speaker <NUM> is configured such that a frame <NUM> can be divided into a magnetic circuit holder member <NUM> and a diaphragm support member <NUM>. The frame <NUM>, however, may be formed of three or more components. The magnetic circuit holder member <NUM> serves as the magnetic circuit holder. The magnetic circuit <NUM> is held inside a holder recess 111a formed in the magnetic circuit holder member <NUM>. In the magnetic circuit <NUM>, the inner structure is formed of the inner front yoke 32b and the inner rear yoke 33b. As is the case for the speaker <NUM> of the first embodiment illustrated in <FIG>, the inner structure and the phase plug <NUM> are fixed to the holder recess 111a by the fixation screw <NUM>. Note that the fixation screw <NUM> is omitted in <FIG>. The outer structure of the magnetic circuit <NUM> is formed of the magnet <NUM>, the outer front yoke 32a, and the outer rear yoke 33a. In the outer structure, the rear end surface 33c of the outer rear yoke 33a is adhered to the bottom of the holder recess 111a. The front magnetic gap G1 and the rear magnetic gap G2 are formed between the inner structure and the outer structure.

As illustrated in <FIG>, the diaphragm support member <NUM> of the frame <NUM> has the pressing portion <NUM> formed integrally with the diaphragm support member <NUM> in a rear end portion thereof. The entire diaphragm support member <NUM> is made integrally by injection molding using a synthetic resin or by die-casting or press forming using a metal. The pressing portion <NUM> has the ring-like body <NUM>, the fixation holes <NUM> formed in the ring-like body <NUM>, and the pressing arms <NUM> protruding toward the center from the ring-like body <NUM>. As illustrate in <FIG>, the magnetic circuit holder member <NUM> has a mounting surface <NUM> that faces frontward (in the Z1 direction). Threaded holes <NUM> are formed at the mounting surface <NUM>. As illustrated in <FIG>, the ring-like body <NUM> is fixed to the mounting surface <NUM> of the magnetic circuit holder member <NUM> using the fixation screws <NUM>, which are inserted through the fixation holes <NUM> and screwed into the threaded holes <NUM>. The fixation holes <NUM>, the threaded holes <NUM>, and the fixation screws <NUM> constitute the screw-fixation portions. The screw-fixation portions fix the magnetic circuit holder member <NUM> and the diaphragm support member <NUM> to each other.

At least the pressing arms <NUM> in the diaphragm support member <NUM> are formed so as to be elastically deformable. As illustrated in <FIG>, the pressing arms <NUM> protrude toward the center axis O from the mounting surface <NUM>. The pressing arms <NUM> press the restriction surface 32d, which is the front end surface of the outer structure of the magnetic circuit <NUM>.

As illustrated in <FIG>, an edge member fixation surface <NUM> is formed at the outer peripheral portion of the front end of the diaphragm support member <NUM>. A damper fixation surface <NUM> is formed at the inner peripheral portion of the diaphragm support member <NUM> at a rear side thereof. The edge member <NUM> is joined to the circumferential portion of the diaphragm <NUM>, and the circumferential edge of the edge member <NUM> is joined to the edge member fixation surface <NUM>. The bobbin <NUM> is joined to the central portion of the diaphragm <NUM>, and the voice coils <NUM> are formed at two positions on a rear side of the bobbin <NUM>. The voice coils <NUM> are positioned inside the respective front magnetic gap G1 and rear magnetic gap G2. The damper <NUM> is joined to the outer peripheral surface of the bobbin <NUM>, and the outer peripheral portion of the damper <NUM> is joined to a damper fixation surface <NUM>.

According to the speaker <NUM> of the third embodiment, the pressing portion <NUM> is formed integrally with the diaphragm support member <NUM>. Accordingly, the pressing portion <NUM> can be positioned and fixed accurately due to the screw-fixation portions fixing the magnetic circuit holder member <NUM> and the diaphragm support member <NUM> together, which eliminates the necessity of positioning the pressing portion <NUM> separately with respect to the magnetic circuit holder member <NUM> and to the diaphragm support member <NUM>. The diaphragm support member <NUM> is structured such that each pressing arm <NUM> is positioned away from the diaphragm support member <NUM> with a space <NUM> provided therebetween, and accordingly the pressing arm <NUM> can elastically deform independently. In other words, the diaphragm support member <NUM> is structured such that when the pressing arms <NUM> that press the outer structure of the magnetic circuit <NUM> deform elastically, the stress is not easily transferred to the diaphragm support member <NUM>. This enables the outer structure of the magnetic circuit <NUM> to be held stably inside the holder recess 111a of the magnetic circuit holder member <NUM>. In addition, this can prevent an excess stress from acting on the diaphragm support member <NUM>.

Claim 1:
A speaker (<NUM>, <NUM>, <NUM>) comprising:
a frame (<NUM>, <NUM>);
a diaphragm (<NUM>) that the frame supports so as to enable the diaphragm to vibrate;
a coil (<NUM>) that drives the diaphragm to vibrate; and
a magnetic circuit (<NUM>) that is positioned rearward relative to the diaphragm and applies a magnetic field to the coil, wherein
the frame has a magnetic circuit holder (<NUM>, <NUM>) in which the magnetic circuit is held,
the magnetic circuit has a restriction surface (32d) that faces frontward;
a pressing portion (<NUM>) with a ring-like body (<NUM>) provided with pressing arms (<NUM>) that protrude from the ring-like body (<NUM>) towards the center axis of the ring-like body, the arms being elastically deformable and disposed so as to be in contact with the restriction surface, and
contact portions between respective pressing arms and the restriction surface are disposed with spacing therebetween in the circumferential direction;
wherein each pressing arm (<NUM>) has a substantially triangular shape of which the width gradually becomes smaller towards a tip portion (42a) of the pressing arm (<NUM>) protruding towards the center of the ring-like body (<NUM>).